Stress hyperglycemia (SH) is a manifestation of altered glucose metabolism in acutely ill patients which worsens outcomes and may represent a risk factor for diabetes. Continuity of care can assess this risk, which depends on quality of hospital clinical documentation. We aimed to determine the incidence of SH and documentation tendencies in hospital discharge summaries and continuity notes. We retrospectively examined diagnoses during a 12-months period. A 3-months representative sample of discharge summaries and continuity clinic notes underwent manual abstraction. Over 12-months, 495 admissions had ≥ 2 blood glucose measurements ≥ 10 mmol/L (180 mg/dL), which provided a SH incidence of 3.3%. Considering other glucose states suggestive of SH, records showing ≥ 4 blood glucose measurements ≥ 7.8 mmol/L (140 mg/dL) totaled 521 admissions. The entire 3-months subset of 124 records lacked the diagnosis SH documentation in discharge summaries. Only two (1.6%) records documented SH in the narrative of hospital summaries. Documentation or assessment of SH was absent in all ambulatory continuity notes. Lack of documentation of SH contributes to lack of follow-up after discharge, representing a disruptor of optimal care. Activities focused on improving quality of hospital documentation need to be integral to the education and competency of providers within accountable health systems. Patients with hyperglycemia in the hospital can be classified into three different categories: known diabetes, undiagnosed diabetes, or true stress hyperglycemia. Stress hyperglycemia is defined as a transient elevation in blood glucose (BG) levels during acute illness or following invasive procedures experienced by patients without diabetes2. It is estimated that 11–12% of hospitalized patients develop stress hyperglycemia, with a linear increase in incidence with advanced age4. This incidence is considerably higher at about 23.9% in critically ill patients admitted to an ICU5, and reported in approximately 80% of cardiac surgical patients6.Stress hyperglycemia is commonly seen in hospitalized patients. There are glycemic and metabolic changes derived from the stress response that accompanies medical procedures and acute illnesses, leading to myriad risks of potential complications7. This acute rise in BG can exacerbate oxidative stress, alter lipid and carbohydrate metabolism, and disrupt the interplay between immune, endocrine, and neural systems8. Disruption of these integral pathways is associated with an increased risk of infectious complications13, mortality in intensive and non-intensive care patients19, and extended hospital stays20. These risks seem to be higher in patients without a previous diagnosis of diabetes27.Pathophysiologic changes involving glucose metabolism occur as a result of stress of illness. An increase in sympathetic stimulation secondary to acute illness, surgery, or trauma causes the release of catecholamines, cortisol, growth hormone, and other counterregulatory hormones that contribute to increased insulin resistance and subsequent elevations of BG concentrations31. This risk seems to increase in a linear fashion that correlates with admission BG level and may lead to a diagnosis of diabetes within 3 years from hospital discharge in 15% of subjects30. Since those patients who develop hyperglycemia in the hospital will need continuity care, it is important to determine whether the glucose abnormality represents underlying diabetes or stress hyperglycemia35.Stress hyperglycemia appears to signal a disturbance in glucose metabolism that may predict a risk of progression to prediabetes and type 2 diabetes35. Historically, clinical practice has been flawed by laxity concerning diabetes management in the inpatient setting36. Hyperglycemia is frequently viewed as a secondary concern, a non-consequential manifestation of acute illness, or a state that will subside upon the resolution of illness. These views potentially allow type 2 diabetes to remain undiagnosed and the conduct of a proper risk assessment, either in the hospital or subsequent to inpatient care to be delayed37.Patients benefit from the diagnostic characterization of their glucose abnormality, optimal management, accurate documentation, and cohesive continuity of care to help reduce morbidity risks associated with stress hyperglycemiaCommunication from the inpatient to the outpatient setting is typically accomplished through discharge summaries that provide relevant information regarding the hospital course. Detailed documentation of pertinent clinical events during hospitalization is often the preamble to comprehensive continuity of care necessary to help reduce risks of disease progression or deterioration, and poor outcomes. However, effective documentation of stress hyperglycemia during hospitalization is not a common practice which can lead to inadequate ambulatory follow-up care.35.The consistency of acknowledgement and documentation of stress hyperglycemia, or how glycemic control is followed after hospital discharge is poorly understood. It is possible that the lack of consensus regarding how to define stress hyperglycemia, based on glucose cutoffs that contribute to hospital outcomes and long term-risk, prevents a more proactive approach to assess, manage and follow these patients. Current clinical guidelines recognize hyperglycemia as BG levels ≥ 7.8 mmol/L (140 mg/dL) and assessment for predisposing causes of hyperglycemia and further testing for possible underlying diabetes should occur. Furthermore, treatment of hospitalized patients should occur if BG levels are persistently above 10 mmol/L (180 mg/dL) regardless of a diagnosis of diabetes to prevent complications associated with hyperglycemiaWe propose that expanding our understanding of scenarios of stress hyperglycemia is essential to enable strategies that can promote awareness about dysglycemia, to recognize of diabetes risk, to adequately claim the complexity of care rendered during hospitalization, and to plan for continuity of care. The purpose of this study is to examine the incidence of stress hyperglycemia and the practice of documentation in the hospital and upon transition of care. We provide recommendations on interventions aiming to (1) improve discharge planning and the quality of discharge summaries and (2) promote continuity of outpatient evaluation to assess risk of, or possible diagnosis of type 2 diabetes in patients with a history of stress hyperglycemia.39. The tools we employed are described below.40. For the purpose of this study, we defined stress hyperglycemia among hospitalized patients as two point-of-care BG levels ≥ 10 mmol/L (180 mg/dL) at least 3 h apart within a 36-h-period during an inpatient encounter without documentation or biochemical evidence of diabetes. Our definition of stress hyperglycemia was more strict than the recommended threshold for monitoring and treatment in guidelines of 7.8 mmol/L (140 mg/dL)33. We used this threshold to avoid equivocal attribution of stress hyperglycemia as its recognition was followed by real-time notifications to clinicians through an alert-based clinical decision support program40.An algorithmic workflow codified to match common data elements corresponding to glycemic data and patient characteristics was used to recognize stress hyperglycemia events among hospitalized patients in real time. The algorithm was instituted as part of a hospital-wide program evaluating clinical decision support in the EHR with the purpose of addressing gaps in glycemic care by providing practice recommendationsA case detection tool and registry identified patients meeting biochemical criteria for stress hyperglycemia and who were lacking documentation of it upon hospital discharge in the diagnosis or problem list based on ICD-10 code , SnoMed, or IMO codes. This design applied criteria to the SAP Business Objects software, which was programmed to query common data elements in the EHR and automatically populate the case registry. In this registry, the BG inclusion criteria based on point-of-care testing was expanded to a- ≥ 7.8 mmol/L (140 mg/dL) once in alignment with criteria for recognition of stress hyperglycemia and screening for diabetes; b- ≥ 7.8 mmol/L (140 mg/dL) at least 4 times, c ≥ 10 mmol/L (180 mg/dL) at least twice, or d ≥ 13.9 mmol/L (250 mg/dL) at least once any time during hospital stay representing the variety of glycemic scenarios that are often encountered in the hospital. This intended to provide a more ample assessment of the frequency of such scenarios. Exclusions included a diagnosis of diabetes, prediabetes, or hyperglycemia already documented in the hospital problem list; biochemical evidence of dysglycemia confirmed by HbA1c ≥ 5.7%, or the use of diabetes medications. These exclusions ensured reliable attribution of stress hyperglycemia to acute illness and not to preexisting abnormal glucose metabolism. Both the algorithmic workflows to recognize real-time events, and the case detection tool and registry represent forms of clinical decision support.We also undertook a direct chart abstraction process which assessed documentation of stress hyperglycemia after hospital discharge. This manual appraisal of documentation of stress hyperglycemia in discharge summaries and follow-up ambulatory notes was conducted in records of patients following within our healthcare system. It was done using a representative sample of admissions corresponding to a 3-months period of the entire 12-months cohort. Records of patients who did not have follow-up care in our health care system after discharge could not be evaluated for continuity.We examined incidence and documentation of stress hyperglycemia in the electronic health records (EHR) among hospitalized adults ≥ 18-years-old through the continuum of care in an academic medical center during a 12-months period. Documentation of stress hyperglycemia during hospitalization course, in discharge summary, and at subsequent ambulatory visits were reviewed from March 2018 to February 2019. Our methods capitalized on EHR’s clinical decision support tools (CDS) to recognize scenarios of stress hyperglycemia. CDS uses person-specific computable health information and intelligent filters and processes data, and applies knowledge in the right clinical context to facilitate decisions to enhance health care and improve health outcomesAll descriptive analyses were performed using SAS version 9.4 . The data were analyzed in three ways. First, an estimate of the incidence of stress hyperglycemia considering the number of patients with at least one event of stress hyperglycemia compared to the adult population without a clinical or biochemical diagnosis of diabetes admitted to an academic health center during a 12-months period. Second, rate of documentation of stress hyperglycemia in the EHR medical problem or diagnosis list upon hospital discharge according to the number of cases reported in the case registry. Third, rate of documentation of stress hyperglycemia in hospital notes and post-discharge ambulatory documents in a representative sample from the case registry.This study was approved by The Penn State College of Medicine Institutional Review Board (IRB) as STUDY00003330. All methods were performed in accordance with the guidelines and regulations set forth by the institution. A waiver of consent was also approved by the Penn State Health, Milton S. Hershey Medical Center Institutional Review Board for this study since all data was deidentified, thus representing no more than minimal risk to the participants.We present the incidence of stress hyperglycemia in the study cohort and show demographics and admissions characteristics of patients during the 12-months of the study period in Table Records showing 4 or more BG values ≥ 7.8 mmol/L (140 mg/dL), denoting milder glucose abnormality but in alignment with a clinical indication for diabetes screening, were used to assess the rate of documentation. Documentation of stress hyperglycemia was absent in the problem list of 521 hospital discharges corresponding to 503 patients meeting point-of-care BG criteria for stress hyperglycemia. There was a greater frequency of stress hyperglycemia among subjects between the 3rd and 7th decades, and a more substantial proportion of admissions corresponded to surgical services. A larger frequency of stress hyperglycemia corresponded to lower degree of hyperglycemia, as shown in Table A 3-months representative sample of the entire cohort lacking recognition of stress hyperglycemia was identified using discrete data elements in the EHR upon hospital discharge. This was examined for any evidence of stress hyperglycemia annotated in the discharge summary and/or continuity care notes after discharge. This yielded 124 admissions corresponding to 119 patients. Patients’ demographics and admission characteristics are presented in Table The incidence of stress hyperglycemia in our study represents levels of hyperglycemia at which consistent glucose monitoring and treatment is recommended. We showcase two important stages of clinical practice that present opportunities to acknowledge and to document stress hyperglycemia, which we believe can enhance acute management and continuity of care. Failure to properly document stress hyperglycemia has implications on preventive care, value-based care, and organizational accountability. All of these attributes are important domains of quality in health care.40. Studies have reported a greater incidence in adult patients admitted to various hospital settings3, due to more inclusive criteria of hyperglycemia compared to our inclusion criteria. Umpierrez et al.utilized a fasting BG value greater than 7.0 mmol/L (126 mg/dL) or two random BG values greater than 11.0 mmol/L (200 mg/dL) as their threshold which yielded an incidence of 12%1. Russo and colleagues utilized any plasma BG value greater than 7.8 mmol/L (140 mg/dL) during a hospital stay as their threshold revealing an incidence of 12.13%3. The exact glucose threshold at which stress hyperglycemia becomes a clinical concern or biochemically defines the condition is unclear. However, clinical practice guidelines suggest a threshold of 7.8 mmol/L (140 mg/dL) to consider the evaluation for underlying diabetes and to continue glucose monitoring33. These guidelines recommend maintaining BG levels between 7.8 mmol/L (140 mg/dL) and 10 mmol/L (180 mg/dL). Glucose levels over 10 mmol/L (180 mg/dL) are associated with an increased risk for mortality, prolonged ventilatory support, renal replacement therapy, hyperbilirubinemia, septicemia, prolonged use of antibiotics, and increased ICU length-of-stay42.The 3.1% incidence of stress hyperglycemia in our study cohort denotes unequivocally elevated glucose values at which providers should consider treatment. Our detection criteria sustained a hospital-wide clinical decision support program employing real-time notifications and provision of practice recommendations43. Considering our conservative incidence of stress hyperglycemia of 3.1% and incidence reported high as 12%, stress hyperglycemia can be encountered ranging from 1.1 to 4.3 million admissions annually. Importantly, many of these patients may have undiagnosed diabetes or are potentially destined to progress to diabetes over the subsequent months to years. This is a staggering number considering studies reporting that patients with stress hyperglycemia have an increased risk of progressing to type 2 diabetes compared to normoglycemic counterparts (3.48 OR)5 and (1.91 h)31. Therefore, the recognition of stress hyperglycemia in the hospital presents an opportunity to provide not only acute management but also an immediate assessment of risk and subsequent monitoring in the outpatient setting. Treating stress hyperglycemia with insulin would commonly require a more compelling glycemic abnormality than the glucose level recommended for screening and documentation. Screening, documenting and treating stress hyperglycemia are distinct and important interrelated elements for adequate practice and continuity of care.Hyperglycemia attributable to the stress of illness warrants proactive recognition by healthcare teams to address the biochemical disarray and enhance awareness of the possible risk for diabetes among populations. In 2018, the United States experienced over 36 million hospital admissions between community and academic centers35.Benefits of thorough documentation include the assessment of glycemic abnormalities in the hospital plan of care, which can facilitate more comprehensive acute management and diabetes screening, proper attribution of a diagnosis for which services were rendered during hospitalization, and provision of valuable information to providers responsible for the continuity of care. In our study, we examined the frequency of cases discharged without a diagnosis of stress hyperglycemia, despite meeting biochemical criteria, revealing 521 missed opportunities. Acknowledgment of the condition can offer patients benefits that may otherwise be overlooked and can facilitate adherence to practice guidelines for monitoring and diagnostic evaluation in patients with stress hyperglycemia44. Similar deficiencies in discharge summaries have been described in heart failure45, dialysis46, and stroke47 cases.Additionally, our analysis revealed that all 124 cases that underwent manual abstraction did not have stress hyperglycemia as a secondary diagnosis in the problem list of their hospital discharge summary, which is the primary means of communication in the transition of care to the continuity care team. Two (1.6%) subjects had hyperglycemia mentioned as part of the narrative section of the hospital course in the discharge summary. This is consistent with documentation rates previously reported in the literature of 5% to 24%48. A cross-sectional survey among physicians indicated that documentation of discharge diagnosis, complications during hospital stay, active medical problems at discharge, and arranged medical follow-up increase the quality of the discharge summary49. Providers understand the purpose and importance of an inclusive discharge summary; however, there is reduced awareness and knowledge regarding the relevance of stress hyperglycemia as demonstrated by the low incidence of the diagnosis. This postulates the need for institutions to develop strategies to reduce shortfalls and implement processes that promote best practices.Nationally, discharge summaries are lacking in terms of timeliness, transmission, and content50. Several institutions have developed quality improvement projects to improve the standards and timeliness of discharge summaries, resulting in statistically significant improvements of multiple domains53. Academic and community medical institutions should consider adopting continuing medical education programs into their curriculum to promote more accurate and timely discharge summaries. It is expected that this practice if reinforced early, will continue as clinicians advance through training into practice and can enhance the accountability of timely diagnosis, proper documentation, and adequate continuity of care.Effective action at different levels is needed to convey to providers the relevance of stress hyperglycemia Table . EstabliIn light of our results reporting on the need for documentation in discharge summaries, we believe it is important to also highlight the presence of documented hyperglycemia and the treatment rendered within daily progress notes over the duration of the hospitalization in our patient cohort. Although our goal was not to analyze daily progress notes for recognition of stress hyperglycemia by the treatment teams, it is important to mention that hyperglycemia was in fact frequently documented in day-to-day inpatient notes; however, the diagnosis of stress hyperglycemia is not being incorporated into discharge summaries which is important for continuity of care.. reported a similar phenomenon, showing only 5% of patients who experienced true stress hyperglycemia received follow-up care for dysglycemia upon discharge34. More broadly speaking, large international studies found that discharge summaries are frequently missing valuable information, contributing to the sub-par quality of continuity care in up to one-fourth of patients54. Inadequate communication in transitions of care hinders continuity of care, leads to an increased rate of hospital readmission, more adverse events, and worse outcomes56. This supports the need for proactive measures to improve documentation quality, highlighting hospitals as essential constituents to the accountability in the continuum of care of patients with hyperglycemia.In our cohort of 60 (48.4%) patients receiving continuity of care within our health system, there was no indication that stress hyperglycemia was addressed or acknowledged during subsequent visits. Tamez-Pérez et al31. In the general population, the median time to diagnosis of type 2 diabetes is 2.4 years, and more than 7% continue to be undiagnosed for at least 7.5 years57. Population health efforts are needed to reduce the number of patients unaware of their condition or those at risk of progressing to diabetes, given the opportunity for early intervention. The American Diabetes Association (ADA) encourages appropriate continuity of care for anyone who develops dysglycemia during their hospital stay35. Therefore, inpatient healthcare teams are in a unique position to identify numerous patients at risk for diabetes, whose only manifestation may be stress hyperglycemia. Prompt recognition and documentation may facilitate risk assessment, early diagnosis, and adequate planning for continuity of care. Our case identification tool and registry enabled recognition of persons at risk for diabetes by recognizing stress hyperglycemia. The utilization of this type of resource facilitates the assessment of populations at risk and can be used to promote the quality of care processes. This aligns with the recommendation of endorsing learning health systems as one of the pillars for centers of excellence for diabetes care58.We propose that the need for close follow-up of stress hyperglycemia arises from the reported progression to type 2 diabetes60 has sought to create a set of standards that offer a framework for efficient and effective transitions of care. We propose that adopting these frameworks will enhance continuity of care and influence long term outcome related to diabetes prevention.Improving the transition of care process from inpatient to outpatient settings has become a priority for stakeholders, including the Centers for Medicare and Medicaid Services (CMS), the National Quality Forum (NQF), the Transitions of Care Consensus Conference (TOCCC), and the ADA, as explained in Table The results of our study reveal an opportunity for identification of patients at risk for diabetes considering their evidence of stress hyperglycemia during acute hospitalization. Lack of recognition of stress hyperglycemia otherwise obstructs proactively caring for the acute abnormality and effectively monitoring and addressing long-term hyperglycemia. Both scenarios have influence in the immediate and the subsequent outcomes of patients. We propose that activities focused on improving the quality of in-hospital documentation of stress hyperglycemia need to be an integral aspect of the education and the competency domains of providers promoted by accountable health care organizations.


Falco tinnunculus) admitted into rehabilitation centres in the Czech Republic. From 2010 to 2019, a total of 12,923 kestrels were admitted to 34 rehabilitation centres with an increasing trend  being found during the monitored period. Subadult kestrels (34.70%) and kestrels injured by power lines (26.57%) were most often admitted. Most kestrels in the rehabilitation centres died or had to be euthanized (81.66%), only 15.90% of the birds could be released back into the wild. The median length of stay in rehabilitation centres for kestrels that were subsequently released was 35 days. Considering survival rates, the most critical threat to kestrels was poisoning (100% of the cases resulted in death) but mortality of the kestrels admitted for most other reasons also exceeded 80%. Given the low success rate of the care of kestrels in rehabilitation centres and the relatively small proportion returned to the wild, it is essential to eliminate the causes leading to their admission, that is, to protect their natural habitats and to prevent unnecessary capture.Rehabilitation centres help injured animals to recover and return back to the wild. This study aimed to analyse trends in intake and outcomes for the common kestrels ( Falconiformes) are a diverse group of birds, however, many of them are endangered species. Eighteen percent of raptors are threatened with extinction and 52% of raptors have declining global populations1. Threats to raptors come primarily from humans and include habitat loss, climate change, poisoning, collisions, electrocutions, deliberate trapping or shooting5. In result, raptors are often admitted to rehabilitation centres6. However, only a few studies focused on the intake and outcomes for raptors at rehabilitations centres so far. Furthermore, they usually have included data for multiple species while total number of birds and rehabilitation centres included in the analyses was very limited. Komnenou et al.6 analysed outcomes for 402 raptors from 19 species admitted to the Veterinary Medical Teaching Hospital in Greece during a 3-year period (1997–2000). Harris and Sleeman7 analysed medical records from 111 bald eagles and peregrine falcons admitted to the Wildlife Center of Virginia from 1993 to 2003. The release rate reported for raptors in those studies was not high, it ranged from 39%7 to 57%6. Given the limited data analysed, the question remains how effective rehabilitation of raptors is. Our study aimed to assess trends in reasons for admission and treatment outcomes for a single species, namely common kestrel. Data from all rehabilitation centres in the Czech Republic during a 10-year period were collected for analysis. The common kestrel was chosen because this species is widespread in the Czech Republic and in consequence it is the raptor species most frequently admitted into rehabilitation centres. The data on species admitted in low numbers would not allow such a thorough analysis. However, we believe that analysis of reasons of admission and outcomes for common kestrels reflect also the threats faced by other raptors and not only in the Czech Republic. We assessed the most common causes of admission of these animals to rehabilitation centres, time spent in rehabilitation centres and the outcomes of rehabilitation. Furthermore, we analysed mortality rates in birds admitted into rehabilitation centres for different reasons. Knowledge of these factors is important for the protection of animals especially in their natural habitat to mitigate impacts of anthropogenic and other factors, which negatively affect common kestrels in the wild.Raptors  is a small raptor from the Falconidae family, widespread throughout Europe, large parts of Asia and Africa, and just as abundant in the Czech Republic8. It is also known as the European kestrel, Eurasian kestrel or Old World kestrel. According to the International Union for Conservation of Nature, the common kestrel is included into the LC (least concern) category, i.e. it is not directly threatened by extinction. However, the International Union for Conservation of Nature, in agreement with some studies, draws attention to the declining trend in the number of these birds9. The common kestrel, like many other animal species, is adversely affected by anthropogenic activity. This activity results in deaths and injuries that reduce the common kestrel's quality of life and thus its populations often decline10. Intensive agriculture also contributes to the decline of common kestrels11. In the past, it has been mainly due to the use of certain toxic substances, such as organochlorides and biphenyls13. In the case of poisoning in raptors, it is also important to mention lead poisoning, caused not only by the use of lead ammunition but by secondary poisoning as well14. As anthropogenic activity changes, its effects on kestrel populations may vary over time. For example, in the second half of the twentieth century Newton et al.15 described a gradual reduction in mortality of sparrow hawks and kestrels due to organochloride poisoning and gunshots and, conversely, an increase of mortality after colliding with traffic. Similarly, the risks to raptors may vary depending on the habitat they inhabit16. Raptors living in the forest are endangered by logging and other species are affected by agriculture1. In addition to poisoning, raptors are also frequent victims of collisions with power lines17.The common kestrel  is provided by rehabilitation centres. Their main goal is to cure these animals and release them back to their natural habitat. This effort involves a range of tasks from the first examination after admission to the rehabilitation centre and determination of the prognosis with regard to the animal's condition and welfare during treatment and up to rehabilitation, which increases the chances of its survival after returning to the wild.P < 0.01).During the period from 2010 to 2019, a total of 12,923 common kestrels were admitted to 34 rehabilitation centres in the Czech Republic, with yearly intake numbers ranging from 911 to 1596 kestrels , followed by admission due to power line injuries (26.57%), other injuries 18.13%), exhaustion, starvation (4.96%) and admission after collision with road traffic (4.57%)  fewer birds were returned to the wild (15.90%). One hundred and fifteen kestrels were still being treated at the end of the monitored period thus they were not included in the outcome analysis.Out of the 12,808 kestrels having their stay in the rehabilitation centre terminated in the monitored period, the majority of birds (81.66%) died or had to be euthanized in rehabilitation centres  in a rehabilitation centre in Spain in the period from 1995 to 2007. These nestlings may be brought unnecessarily, as kestrels can nest in the immediate vicinity of humans29 and thus arouse their attention or pity. However, these may also be weakened young during periods without plentiful prey, thus reducing the success of nesting and the number of raised nestlings30. Kestrels protect their nests31, but the presence of humans or noise is stressful and may result in the abandonment of the nests32. The negative consequences of noise and other factors related to birds nesting near human dwellings were described by e.g. Baudains and Lloys33, French et al.34 and Halfwerk et al.35.The reasons for admitting common kestrels to rehabilitation centres in the Czech Republic were very diverse. Most frequently admitted were nestlings (34.70%) and birds injured by power lines (26.57%). Similarly, Molina et al.2 because some of the carcasses can be taken away by scavengers36. However, a high mortality rate was confirmed by various studies38. The mortality rate can be so high that it affects a population in the area39. Over a ten-year period, Rodríguez et al.5 observed a raptor rehabilitation centre in Tenerife, where common kestrels predominated among the admitted raptors, and found that various injuries, including collisions with power lines, were the most common reason for admission (42.2%). The birds that were not killed immediately may be left burned and unable to fly. Power lines, including unsafe power poles, can cause serious injuries to which raptors are particularly susceptible because of specific morphological features (such as their large size and wingspan) and behavior (frequent perching or nesting on power poles)42. More research is needed on the effects of application of mitigation measures and solutions must be developed on a case-by-case basis44. Some pylons can cause higher mortality in birds than others, depending on, for example, their height and position45 or technical design46. Individual measures must also be considered from the point of view of specific species or groups of birds. Differences in perching behavior and possibility of electrocution cause differences in effectiveness of modifications. Insulation of crossarm braces seem to be effective even for the small raptors including kestrels47.Worldwide, collisions and electrocution by power lines are responsible for the death of many birds, especially raptors. The number of carcasses near power lines may not accurately reflect the number of birds killed by power lines48; in Greece, between 1997–2000, 56.90% of raptors admitted to a clinic were released6; in Spain, between 2003–2013, 57.57% of raptors were released49; and in Tenerife, between 1998–2007, 44.4% of raptors admitted to a rehabilitation centre were released5. In all studies, the total number of raptors was assessed without distinction between various species. Thus, it is not clear how many or if any common kestrels were included and what release rates for individual raptor species were. Furthermore, while the release rates were low for common kestrels in the general wildlife rehabilitation centres operating in the Czech Republic, specialized raptor centres might be more successful when providing treatment to raptors showing the advantage of specialization in rehabilitation centres.Out of the 12,808 common kestrels with known outcomes during the monitored period, 9,920 (77.45%) birds died and 539 (4.21%) birds had to be euthanized due to incurable conditions or diseases. A successful recovery leading to release of the birds back to the wild was uncommon; it was the outcome for only 2,037 (15.90%) birds. Interestingly, a considerably higher percentage of released raptors was reported in some other studies. In Jordan, between 2017–2018, 55.80% of raptors admitted to a rehabilitation centre were released50. Evaluation of blood parameters may be helpful for adjustment of treatment51. Prognosis may also be influenced by other factors during the kestrel's life that animal rehabilitation workers are unable to identify. Some studies have addressed the causes of death in raptors, but none focused on species-specific causes. Sara and Craig52, in a rehabilitation centre in Alabama between 1999–2000, reported higher mortality in adult raptors than in young birds. They explain higher mortality in adult birds by older raptors being less tolerant of human handling. Human handling is highly stressful for raptors. As a consequence of stress they may refuse to feed, which further reduces their chances of recovery, especially in the case of long-term captivity53. Correspondingly, higher mortality in mature raptors  admitted to rehabilitation centres including those that were healthy at the time of admission (unnecessary capture) in comparison with nestlings  was found in our study. Furthermore, Sara and Craig52 reported higher mortality in raptor species that are naturally active during the day. They suggest that raptors with diurnal activity are more frequent victims of shooting or road traffic. This may also apply to common kestrels that are diurnal hunters.Treatment options for raptors are constantly improving, yet knowledge of the individual requirements of a given species is still very important, along with performing autopsies and identifying the factors that lead to deaths54 found the same length of stay in cases of euthanasia for all animals admitted to a rehabilitation centre in Catalonia. Euthanasia administered shortly after admission is the result of a rapid assessment of the animal's health and its chances of recovery and return to the wild. This rapid decision-making is very important in minimizing the individual's suffering during treatment, especially when treatment success and the animal's return to the wild are uncertain or unlikely55. The results of our study, in which only a very small percentage of birds were euthanized compared to the total number of kestrels that died in treatment, suggest that rehabilitation centres in the Czech Republic made greater efforts to rehabilitation kestrels even in the case of an uncertain prognosis. Corresponding to this is the longer time spent in the rehabilitation centre before death found in our study (median 9 days) than found by Molina et al.54 in Catalonia (2 days). It remains to be seen whether this approach is appropriate from the point of view of bird welfare. Efforts to rehabilitation animals with a poor prognosis increase their suffering, so it is necessary to consider the benefits of treatment with regard to their welfare, especially for wild animals56. The finding of unassisted death being more prevalent than euthanasia was reported also by other studies exploring various species of animals admitted to rehabilitation centres, e.g. reptiles, amphibians, mammals or birds54 or hedgehogs27. Kelly and Bland28 reported the number of individuals that died or were euthanized after unsuccessful treatment (more than 40%) as comparable to those euthanized upon admission to the rehabilitation centre (approximately 35%) in Eurasian sparrow hawks (Accipiter nisus) admitted to a rehabilitation centre in England from 2000 to 2004.The length of stay in the rehabilitation centre differed according to the outcome. Statistically, the kestrels that died or had to be euthanized spent a significantly shorter time in rehabilitation centres than those that were treated successfully and subsequently released. The decision to euthanize was usually made on the day of admission to the rehabilitation centre (median 0.5 days). However, even among the birds that were considered curable and provided with treatment, many of them died within a few days (median 9 days). Molina et al.57 found a high sensitivity to poisoning in the Falconidae family, noting that falcons are more susceptible to ammonium chloride poisoning than, for example, lead poisoning58. In our study, very high mortality rates were also found in kestrels admitted due to infectious diseases (96.83%), road traffic injuries (89.34%) and power line injuries (84.45%). Molony et al.55 also pointed out that mechanical injuries to animals are the most severe and common reasons for euthanasia. Survival can also be affected by finders attempting to take care of the birds on their own59. According to the Czech legislation, the care for injured wild animals can be provided only by the competent persons, i.e. persons holding a certificate of competence. Unfortunately, not all people are aware that by law they are obliged to notify the authorized rehabilitation centre in case of finding an injured wild animal and that it is illegal to take such an animal home. However, the results show that not only birds that were admitted to rehabilitation centres due to injury or disease had been dying there. A high mortality rate (77.13%) was found also in birds that were captured and brought to the rehabilitation centre unnecessarily.Our study revealed that common kestrels admitted to rehabilitation centres had a very high mortality rate overall, almost regardless of the reason for admission. However, some differences in the chance of survival depending on the cause of admission were found. Kestrels admitted due to poisoning seem to have a zero chance of survival, none was rescued during the monitored period. Lead poisoning in raptors is often the consequence of the use of lead ammunition by hunters. Lead bullets are prohibited to be used in waterfowl, but not in other game, and secondary poisoning can occur in kestrels via their prey. For eagles and other raptors, lead is most toxic when consumed, as opposed to lead bullets or shot simply lodging in muscle tissue. Also widespread use of rodenticides is responsible for secondary poisoning to non-target species including raptors. Naldo and Samour6. As shown by results of our and many other studies, one of the biggest threats to avian species are electric power lines. To reduce risks, it is possible to alter the poles and lines so that they are less dangerous to raptors60. The protection of raptors would be improved by greater safety of electrical infrastructure61. It is also important to educate the public in order to reduce the number of birds caught unnecessarily or to prevent unprofessional treatment of birds provided by the enthusiastic but incompetent finders. To ensure the successful return of birds from rehabilitation centres to the wild, it is essential to release healthy individuals at suitable locations that increase their survival chances. The time spent in captivity does not seem to impair prey-capture abilities of predation in the common kestrel62 yet in many respects, it is useful to monitor survival rates of raptors released after rehabilitation63.The results of the study show that the success rate of the care for common kestrels in rehabilitation centres in the Czech Republic during the monitored period was not particularly high. In order to strengthen the protection of kestrels, it is, therefore, essential to primarily focus on their protection in the wild and eliminate factors contributing to the various causes of death and injury. Such measures include the minimization of human interventions in nature, the protection of habitats and the elimination of other risk factors, in particular those related to anthropogenic activity, as they have a major impact on the mortality and morbidity of raptorsNational rehabilitation centre data provide valuable information on the causes of injuries in common kestrels and thus the threats posed by human-altered habitats. Rehabilitation centres generally play an important role in caring for injured, diseased or displaced animals in an effort to release them back to the wild, but the results of our study show that in kestrels, this care is not as successful as in other species. Only a very small portion of the admitted birds could return to the wild. It is therefore essential to focus on prevention, i.e. on factors leading to admission of kestrels to rehabilitation centres. Many kestrels were admitted to rehabilitation centres due to the consequences of anthropogenic activity, especially power line injuries. The technical solutions to this problem already exist, but it is necessary to apply them more widely and effectively. The admission of young kestrels could be often prevented by elimination of human interventions during nesting. Public education is crucial also to avoid unnecessary capture of birds and risks posed to birds by domestic animals, use of chemicals and nettings.64. The records kept by rehabilitation centres contain data on all common kestrels admitted to the rehabilitation centres in the Czech Republic including the reason and date of admission and the outcome for each individual bird. All rehabilitation centres included in the study were general wildlife rehabilitation centres as there are no specialized raptor centres in the Czech Republic. Operation of the rehabilitation centres within the National Network of Rehabilitation Centres of the Czech Republic including the record keeping duty is regulated by the law as they are all state-funded.The data on common kestrels admitted to rehabilitation centres in the Czech Republic were obtained from the records of the Ministry of the Environment as the central state administrative authority in environmental affairs. The subject of the analysis was the records collected from all rehabilitation centres falling under the National Network of Rehabilitation Centres of the Czech Republic from January 1, 2010 to December 31, 2019. The rehabilitation centres are obligated to provide each injured wild animal found with a complex care routine including first aid, veterinary treatment, therapy and rehabilitation. A handicapped animal is defined by Czech legislation as a wild animal that is temporarily or permanently unable to survive in the wild due to injury, illness or other factorsFor the purposes of statistical evaluation, the kestrels were divided into groups by the year of admission to rehabilitation centres, the reasons for admission to rehabilitation centres and the outcomes. For common kestrels with known admission and discharge dates, the length of stay was also calculated and evaluated.The categories of the reasons for the admission and outcomes groups correspond to the guidelines for the evidence of admitted animals in rehabilitation centres in the Czech Republic Table . All youWe calculated the length of stay of the kestrels in rehabilitation centres as the difference between the date of admission and the date when the stay of a kestrel in the rehabilitation centre was terminated. The kestrels for which the dates were not recorded and those that were still treated in the rehabilitation centre at the end of the monitored period were excluded from this analysis as it was not possible to determine their length of stay. For kestrels which were admitted on the same day as their record was terminated, the length of stay was set to 0.5 days. It is an estimate of the time needed to determine the diagnosis and prognosis . The median length of stay was calculated separately for each outcome group.P < 0.05 was determined to be statistically significant.The data were evaluated using the statistical program UNISTAT 6.5 for Excel . In assessing the change in the number of recorded common kestrels, we used the Spearman coefficient to determine the coefficient of order correlation. A chi-square test with Yates correction within the methodology of 2 × 2 contingency tables was used for statistical evaluation of frequency differences within individual groups with numbers of individuals > 5. We used the Kruskal–Wallis ANOVA (and multiple comparisons for t-distributions) to statistically compare the length of stay among the individual categories of birds according to their outcome. In the tests used, the value of


Echinochloa colona, are becoming problematic in the eastern grain region of Australia, but cover crops can be useful to suppress weeds during the summer fallow period. The present study evaluated the growth and seed production of E. colona grown alone or with four and eight cover crop plants per pot . Four legume  and two grass (forage sorghum and Japanese millet) cover crops were used. Interference by cover crops reduced the height, the number of leaves and tillers, inflorescence number, seed production, and biomass of this weed than when it was grown alone. Cover crops differed in their ability to suppress the growth and seed production of E. colona. The effect of cover crop density on the studied attributes was non-significant in most cases. Pigeonpea as a cover crop was the least effective in suppressing the growth and seed production of E. colona. In general, leguminous cover crops exhibited less suppression of E. colona than grasses. Forage sorghum was most efficient in reducing the growth of this weed. Forage sorghum and Japanese millet reduced E. colona leaf and tiller numbers per plant by 90 and 87%, respectively. These cover crops reduced E. colona leaf number to only 17 per plant as against 160 per plant recorded without cover crops. Inflorescence number per E. colona plant growing alone was as high as 48. However, it was reduced by 20–92% when this weed was grown with cover crop plants. E. colona’s seed production was significantly suppressed by all the cover crops, except pigeonpea. Biomass of E. colona was suppressed largely by forage sorghum and Japanese millet compared to other cover crops. Among the cover crops, pigeonpea produced the lowest biomass of 11 g pot-1, and the highest biomass (114 g pot-1) was produced by forage sorghum. The study demonstrated the usefulness of cover crops, especially forage sorghum and Japanese millet, to suppress the growth and seed output of E. colona.Summer weed species, including  Echinochloa colona (L.) Link is a problematic annual C4 grass weed of 35 cropping systems in more than 60 countries globally, especially in tropical and subtropical regions of Asia, Africa, and Australia , forage sorghum , Japanese millet , lablab , pigeonpea  and soybean . The cover crop densities of four and eight plants per pot  were maintained by sowing seeds of the respective cover crop as per treatment equidistant from each other. The cover crop seeds were sown at a depth of 3 cm and a distance of 11 cm from E. colona seeds. The selected cover crop densities represent different levels of shading caused by cover crops after canopy closure. The weed and cover crop plants emerged within 6–8 DAS. The pots were irrigated daily using an automated irrigation system so that moisture was not limiting. The experimental pots were placed at a distance of 50 cm from each other and moved to a new position weekly to avoid any position effect.Seeds of E. colona growth and seed production was quantified by measuring plant height, and the number of leaves, tillers, inflorescence, and seeds at 56 DAS. E. colona plant height was measured from the base of the plant to the tip of the uppermost leaf. The study was terminated at 56 DAS when the lower leaves of E. colona started turning yellowish. At harvest, the number of inflorescences and seeds plant-1 for E. colona was counted. The aboveground biomass of E. colona was measured after drying the harvested plant samples in an oven at 70°C for 48 h. Height and aboveground biomass of cover crops were measured at harvest. No insect attack or disease incidence was observed during the study period, and hence no curative measures were undertaken.The effect of cover crop interference on th edition; VSN International, Hemel Hempstead, UK). Data were pooled across the runs  for further statistical analyses as no significant interaction between treatments and experimental runs were observed. Differences amongst treatment means were evaluated by Fisher’s protected Least Significant Differences  test.The study was conducted using a completely randomized design with four replications and there were three experimental runs from September 2019 to April 2020. A new experimental run was initiated within a month of termination of the previous run. Before analyses, the homogeneity and normality of data were checked, and analysis of variance (ANOVA) was performed using GenStat   . The heiE. colona was noticed when this weed was grown in interference with cover crops  than the rest of the cover crops used in the present study (-1), and Japanese millet plants recorded the next higher biomass (53.1 g pot-1).Cowpea, lablab, pigeonpea, and soybean plants had similar plant height . The talnt study . Forage E. colona reduced the height, leaves, and tillering capacity of this weed. The reduction in weed growth attributes due to the cover crop interference is related to diverse mechanisms involving resource deprivation, modification in microclimate elements such as temperature and light regimes, moisture contents, and allelopathy   . Cover c& Chase] . Cover c& Chase] . The faclishment .E. colona. In a recent study, an increase in mungbean [Vigna radiata (L.) R. Wilczek] density from 164 plants m-2 to 246 plants m-2 increased the suppression magnitude of Sonchus oleraceus L. shoot biomass from 69% to 86% [Ludwigia octovalvis (Jacq.) Raven, while no such suppressive effect was observed on Amaranthus spinosus L [-2) of cover crops will be sufficient to provide effective suppression of weeds.Increased crop density can contribute towards crop competitiveness against weeds. However, in the present study, the increased density of cover crops did not affect the height and biomass of % to 86% . Howeverinosus L . In our E. colona growth and seed production and support the recommendation of a fast-growing, weed suppressive, and competitive cover crop to suppress weeds [E. colona seed production was significantly reduced and plants of this weed growing in interference with forage sorghum and Japanese millet produced only 300–400 seeds plant-1, this amount of seed output is enough to cause heavy infestations in years to come [E. colona, sole reliance on cover crops to suppress weeds is not viable in the backdrop of long-term weed management.Seed production is a vital attribute governing the weed seedbank and overall weed population dynamics under field conditions. Our results suggest that interference by cover crops like forage sorghum and Japanese millet can help in reducing ss weeds , 19. A lss weeds . Moreovess weeds . Althoug to come . NeverthE. colona and other problematic weeds. Cover crops grown as mixtures also need to be explored.The use of forage sorghum and Japanese millets as vigorous ground cover crops during the fallow period will suppress weeds and provide much-needed improvement in soil quality. However, to harness the full benefits of agroecosystem services rendered by cover crops, fine-tuning is needed, and these should be used in conjunction with other weed control measures to have a broader impact on weeds with a low amount of seeds reaching the seedbank. These cover crops need to be further validated under field conditions to suppress


Assistive robots support persons with disabilities to improve their quality of life and independence. These robots make the life of a physically weak person more comfortable and useful to society. They sense, process sensory information, and execute actions that are helpful to the disabled person. Similarly, these robots carry out rehabilitation by understanding and augmenting the rehabilitation process through a robotic system. These robots are expected to assist different sensorimotor functions, therapeutic training, and assessment of the sensorimotor performance of the patients.Assistive and rehabilitation robotic technologies have developed rapidly expanding the horizon of the field of robotics. These technologies are vital in the society in which around one billion among the growing global population experience some form of physical disability impacting everyday life. Assistive and rehabilitation robotic research, especially exoskeleton robotic research integrates advanced mechatronics and intelligent sensing to restore weak sensorimotor functions. Controlling these robots according to the requirement is one of the challenging tasks. Electromyography (EMG) signals have extensively been used to control assistive robots such as exoskeleton robots so that the wearer is free of actuating any additional device to control the robot. Additionally, many studies have been carried out recently to investigate the possibility of using Electroencephalography (EEG) signals to control robotic devices.This Research Topic is aimed at creating a multidisciplinary forum of discussion on the recent advances in controlling assistive and rehabilitation robots presenting the diversity of the current approaches. It was expected to include Research Topics related to developments of controllers for upper limb/lower limb robotic exoskeletons, biomechanical investigations of robotic exoskeletons and other assistive robots, novel sensors for exoskeleton robots to generate human-like motions, EMG/EEG signals-based exoskeleton robot control, mathematical and physical algorithms for control of exoskeleton robots, assessment and benchmarking of exoskeleton robots' functionality, and clinical studies of assistive robot control. The Research Topic received overwhelming attention from the relevant researchers. Eleven articles have been selected to be published on this Research Topic after carrying out a rigorous peer-review process. Out of 11 articles, seven articles are based on the use of EMG signals for the control of assistive and rehabilitation robots. They areToward Hand Pattern Recognition in Assistive and Rehabilitation Robotics Using EMG and Kinematics of Zhou et al.Multi-Joint Angles Estimation of Forearm Motion Using a Regression Model of Qin et al.A Multi-Information Fusion Method for Gait Phase Classification in Lower Limb Rehabilitation Exoskeleton of Zhang et al.Face-Computer Interface (FCI): Intent Recognition Based on Facial Electromyography (fEMG) and Online Human-Computer Interface with Audiovisual Feedback of Zhu et al.Improved Motion Classification with an Integrated Multimodal Exoskeleton Interface of Langlois et al.Robust Torque Predictions from Electromyography Across Multiple Levels of Active Exoskeleton Assistance Despite Non-linear Reorganization of Locomotor Output of George et al.Control of Newly-Designed Wearable Robotic Hand Exoskeleton Based on Surface Electromyographic Signals of Li et al.Another three articles are based on the use of EEG signals.Engagement Enhancement Based on Human-in-the-Loop Optimization for Neural Rehabilitation of Wang et al.Multi-Feature Input Deep Forest for EEG-Based Emotion Recognition of Fang et al.The Differences Between Motor Attempt and Motor Imagery in Brain-Computer Interface Accuracy and Event-Related Desynchronization of Patients with Hemiplegia of Chen et al.Evaluating Convolutional Neural Networks as a Method of EEG–EMG Fusion” of Tryon and Trejos presented the use of EMG and EEG signals with a hybrid approach to control the assistive and rehabilitation robots.The article titled “Out of seven articles discussed on the EMG signals-based control of assistive and rehabilitation robots, in three articles EMG signals have been used for the control of upper-limb rehabilitation robots. Another two of the articles explained the uses of EMG signals for lower-limb exoskeleton robots and the rest of the articles described the classification of EMG signals to use for rehabilitation purposes.The physiological and neurological differences among individuals can cause divergent responses to the same task, and the responses can further change considerably during training; both of these factors make engagement enhancement a challenge. This challenge can be overcome by training task optimization based on subjects' responses. In one article an engagement enhancement method based on human-in-the-loop optimization is proposed and the performance of the proposed method is demonstrated by the validation and comparison experiments. The results show that both subjects' surface EMG (sEMG) -based motor engagement and electroencephalography based neural engagement can be improved significantly and maintained at a high level.Another article proposes a feature fusion and decision fusion method that combines EMG features and kinematic features for hand pattern recognition toward application in upper limb assistive and rehabilitation robotics. Ten normal subjects and five post-stroke patients participating in the experiments were tested with eight hand patterns of daily activities while EMG and kinematics were recorded simultaneously.A prosthetic hand with high accuracy and robustness are necessary to improve the life quality of forearm amputees. The application of sEMG signals to control a prosthetic hand is challenging. The authors of one of the articles have proposed a time-domain Convolutional Neural Network (CNN) model for the regression prediction of joint angles in three degrees of freedom (DoFs) and 5-fold cross-validation was used to evaluate the correlation coefficient. The 3DOFs includes two wrist joint motion and one finger joint motion. In this study, CNN models were developed using combined EEG–EMG inputs to determine if they have potential as a method of EEG–EMG fusion that automatically extracts relevant information from both signals simultaneously. EEG and EMG signals were recorded during elbow flexion-extension and used to develop CNN models based on time-frequency and time-domain image inputs.It is very important to have a natural, stable, and comfortable human-computer interface for controlling rehabilitation assistance robots to solve problems of patients who have lost limb control ability, such as upper limb amputation and high paraplegia. One article presents a complete limbs-free face-computer interface framework based on facial electromyography including offline analysis and online control of mechanical equipment.One of the studies covered in this Research Topic explored the accuracy of the Brain-Computer-Interface (BCI) and event-related desynchronization between the two tasks. The articles identified the promise and the challenges faced by the field of assistive and rehabilitation robotic technologies and identified the critical need for additional prospective, in the design and control of relevant robots. Another article demonstrated a new wearable robotic hand exoskeleton with multi joints, higher degrees of freedom, and a larger range of motion. The exoskeleton hand comprises six linear actuators and can realize both independent movements of each digit and coordinative movement involving multiple fingers for grasp and pinch. The kinematic parameters of the hand exoskeleton were analyzed by using a motion capture system.EMG/EEG Signals-Based Control of Assistive and Rehabilitation Robots. All articles underlined both the promise and the challenges faced by the field of assistive and rehabilitation robots. The articles further recognized the need for additional perspective, in the control of these robotic devices. In summary, all the articles presented in the Research Topic have set a new trend in EMG/EEG Signals-Based Control of Assistive and Rehabilitation Robots.This Research Topic provides a snapshot of the current status of research on the All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


A ecocardiografia é essencial para o diagnóstico e a quantificação da insuficiência aórtica (IA). A integral velocidade-tempo (IVT) do fluxo da IA pode estar relacionada à gravidade da IA. Este estudo tem por objetivo avaliar se a IVT é um marcador ecocardiográfico de gravidade da IA. Foram incluídos todos os pacientes com IA nativa moderada ou grave e ritmo sinusal que visitaram o nosso laboratório de imagem entre janeiro e outubro de 2016. Todos os indivíduos foram submetidos a um ecocardiograma completo com medição da IVT da IA. A associação entre a IVT e a gravidade da IA foi analisada por regressão logística e modelos de regressão multivariada. Valores p<0,05 foram considerados estatisticamente significativos.odds ratio 0,160, p=0,032) e da frequência cardíaca e pressão arterial diastólica (PAD) . Entre os 62 pacientes incluídos , a IVT foi maior em indivíduos com IA moderada em comparação àqueles com IA grave . Pacientes com IA grave apresentaram valores maiores de diâmetro diastólico final do ventrículo esquerdo (DDFVE) , volume diastólico final do ventrículo esquerdo (VDFVE) , orifício regurgitante efetivo  e volume regurgitante , assim como menor fração de ejeção do ventrículo esquerdo (FEVE) . A IVT mostrou ser um marcador de gravidade da IA, independentemente do DDFVE, VDFVE e FEVE  A ecocardiografia é uma ferramenta fundamental para o diagnóstico e a quantificação da IA2 e sua interpretação correta requer uma abordagem que integra medidas e parâmetros qualitativos, semiquantitativos e quantitativos.4 No entanto, estes parâmetros não estão isentos de limitações.3Insuficiência aórtica (IA) é uma das incompetências valvulares mais comuns no mundo desenvolvido.5 Em pacientes com IA, a IVT é multiplicada pelo orifício regurgitante efetivo (ORE) da aorta para calcular o volume regurgitante (VR) (VR=ORExIVT).7 Este parâmetro tem demonstrado sua eficácia na determinação da gravidade da IA, mesmo com o valor do ORE sendo calculado com base no método de área da superfície de isovelocidade proximal , que é conhecido por ter limitações inerentes em pacientes com IA.9 Além disso, tendo em conta a referida equação, pacientes com IA grave geralmente apresentam valores maiores de VR2 e ORE,10 mas não há evidência do comportamento da IVT em relação à gravidade da IA.A integral velocidade-tempo (IVT) é definida como a área medida abaixo da curva de velocidade Doppler em um determinado ponto. No caso da IA, este valor corresponde ao gradiente de pressão diastólica entre a aorta e o ventrículo esquerdo (VE).11 bem como pressão arterial diastólica (PAD) reduzida.13 Estas mudanças de pressão podem diminuir a IVT fisiopatologicamente por meio da redução do gradiente de pressão entre a aorta e o VE. Este estudo tem por objetivo determinar se a IVT é um marcador ecocardiográfico de gravidade da IA.Ademais, pacientes com IA grave costumam ter pressão diastólica final do VE elevada,Este estudo observacional transversal retrospectivo foi realizado durante dez meses (de janeiro a outubro de 2016). Todos os pacientes com IA que visitaram o nosso laboratório de imagem cardíaca durante este período foram considerados elegíveis. Os pacientes tinham que apresentar IA moderada a grave em uma valva nativa , além de assinar um termo de consentimento livre e esclarecido para serem incluídos no estudo. Foram excluídos os pacientes com fibrilação atrial ou evidência de qualquer tipo de arritmia, jatos múltiplos ou excêntricos de IA. O estudo foi conduzido em conformidade com a declaração de Helsinki e foi aprovado pelo comitê de ética da nossa comissão de pesquisa local.European Society of Hypertension/European Society of Cardiology – ESH/ESC).14 A pressão arterial final foi a média da segunda e terceira aferições. A frequência cardíaca (FC) foi determinada no momento da medição da IVT da IA. Todos os pacientes também tiveram um exame de sangue realizado imediatamente após a coleta para determinar o nível de creatinina plasmática e calcular a taxa de filtração glomerular, com base na equação CKD-EPI ( Chronic Kidney Disease – Epidemiology Collaboration ).15 O analisador hematológico usado foi o PE Chemistry .Todos os participantes do estudo tiveram as seguintes informações demográficas e clínicas coletadas: idade, sexo, histórico de hipertensão arterial, dislipidemia, diabetes mellitus e tabagismo. Qualquer tipo de medicamento anti-hipertensivo, hipolipemiante ou antiarrítmico que os participantes estivessem tomando no momento da inclusão no estudo também foram registrados. Durante o ecocardiograma, a altura e o peso de cada paciente foram coletados e três aferições da pressão arterial foram realizadas após 5 minutos de repouso, usando um monitor de pressão arterial M6 Comfort HEM-7221-E8  – validado por protocolos da Dabl®Educational Trust e da Sociedade Britânica de Hipertensão –, de acordo com as recomendações da Sociedade Europeia de Hipertensão/Sociedade Europeia de Cardiologia , diâmetro sistólico final do ventrículo esquerdo (DSFVE) e a fração de ejeção do ventrículo esquerdo (FEVE), em conformidade com as recomendações da Sociedade Americana de Ecocardiografia.câmaras    ou o pa19 Análises de confiabilidade utilizando a estatística kappa (κ) definiram a concordância entre os dois ecocardiografistas quanto à gravidade da IA (moderada ou grave). Diferenças iniciais entre pacientes com IA moderada ou grave foram avaliadas pelo teste t de Student não pareado ou pelo teste U de Mann-Whitney para as variáveis contínuas e pelo teste χ2 para as variáveis categóricas. A análise de regressão logística avaliou a associação entre cada variável de referência e a IA grave. Modelos de regressão logística multivariada determinaram as variáveis independentemente associadas com IA grave. As variáveis incluídas foram aquelas com p<0,05 na análise univariada, excluindo o VR, o ORE e a VC por não estarem disponíveis para todos os pacientes, o que poderia causar sobreajuste. O desempenho do modelo em prever a IA grave foi avaliado por medidas de calibração (estatística de Hosmer-Lemeshow) e discriminação (índice C), ambas internamente validadas utilizando a técnica de reamostragem bootstrap . A associação entre a IVT da IA e sua gravidade foi explorada por meio de análise multivariada, independentemente da FC e da PAD. A relação entre o iIVT e a gravidade da IA foi avaliada em uma nova análise de regressão logística. Intervalos de confiança (IC95%) foram fornecidos quando necessário. Todos os valores de probabilidade foram bilaterais e valores p<0,05 foram considerados estatisticamente significativos. A análise estatística foi realizada utilizando o programa SPSS, v.18.0 .A distribuição normal foi testada em todas as variáveis pelo teste de Kolmogorov-Smirnov. Variáveis contínuas com distribuição normal foram expressas como média±desvio padrão (DP) e as com distribuição assimétrica como mediana [intervalo interquartil (IIQ)]. As variáveis categóricas foram expressas como porcentagem. As correlações foram estudadas por meio do método de Spearman ou de Pearson, conforme apropriado. A variabilidade inter-observador para a quantificação da gravidade da IA foi determinada pelo coeficiente de correlação intraclasse e plotagens de Bland-Altman.A amostra original foi composta de 65 pacientes com IA nativa moderada ou grave em ritmo sinusal. Não foi possível obter um alinhamento adequado do Doppler para o jato regurgitante em três pacientes, que apresentaram jatos muito excêntricos, sendo portanto excluídos. Dos 62 participantes restantes, 40  tinham IA moderada e 22 , IA grave. IA aguda foi diagnosticada em 4 pacientes . A concordância entre a quantificação definida pelos dois ecocardiografistas foi κ=0,83. Todos os pacientes incluídos eram caucasianos. As características de referência da amostra estão presentes na p)=-0,408, p=0,001]. Pacientes com IA grave apresentaram menor FEVE e maior DDFVE, DSFVE, ORE, VR e VC. No entanto, a medida correta destes parâmetros só foi possível em 62,9% da amostra para o ORE, 67,7% para o VR e 72,6% para a VC. Salienta-se que não foi identificada associação estatisticamente significativa entre a gravidade da IA e o TMP, embora uma tendência para isso tenha sido detectada.Como mostra a p=0,905, p<0,001) e o VDFVE , respectivamente. Também foram excluídos da análise multivariada o ORE, o VR e a VC, já que eles não puderam ser obtidos para todos os pacientes devido à janela ultrassonográfica inadequada ou dificuldade na medição. Este modelo mostrou maior discriminação  e uma calibração precisa .Na análise bivariada   , a IVT Por outro lado, como a FC e a PAD poderiam influenciar fisiopatologicamente a medição da IVT , a associação entre a IVT e a gravidade da IA foi avaliada com ajuste para FC e PAD. A IVT também foi inversamente relacionada à gravidade da IA, independentemente desses fatores . Por último, o iIVT da IA também mostrou associação inversa com a gravidade da IA    e agiu 20Este estudo sugere que a IVT da IA pode ser usada como um marcador de gravidade em pacientes com IA significativa, considerando que a estimativa da gravidade por meio da ecocardiografia é um processo difícil que envolve a integração de vários exames e parâmetros diferentes.7 e uma relação indireta pode ser identificada entre o ORE e a IVT (ORE=VR/IVT).10 A IA mais grave apresenta ORE e VR maiores, mas o comportamento da IVT é desconhecido. Neste estudo, a IVT do fluxo regurgitante da aorta foi inversamente associada com a gravidade da IA. Há pouca evidência científica disponível corroborando essa relação. Zarauza et al.,21 publicaram um estudo que avaliou o valor da IVT da IA, entre outros parâmetros, em uma amostra de 43 pacientes com IA moderada a grave.21 Os autores revelaram achados semelhantes aos encontrados na presente investigação . Contudo, no estudo de Zarauza et al.,21 as diferenças entre a IVT da IA grave e moderada não alcançaram significância estatística. A diferença no tamanho da amostra de pacientes com IA moderada (15 versus 40) poderia explicar a falta de um resultado significativo. Até onde sabemos, nenhum estudo avaliou o valor da IVT como um indicador de gravidade da IA.Efetivamente, o ORE pelo método PISA funciona como um parâmetro de estratificação da gravidade da IA24 Acredita-se que este aspecto reflete uma metodologia adequada e rigorosa para a medição desses parâmetros. Este estudo identificou que a relação entre a IVT e a gravidade da IA não depende de variáveis ecocardiográficas, como diâmetros, volumes ou fração de ejeção do ventrículo esquerdo. Este resultado poderia potencialmente respaldar o uso da IVT como indicador na maioria dos cenários ecocardiográfico envolvendo a IA e o ritmo sinusal.Um aspecto notável do presente estudo é a associação direta entre a gravidade da IA e os diâmetros e volumes diastólico final e sistólico final, além da relação inversa com a FEVE. Estes resultados corroboram as evidências científicas disponíveis, que defendem o papel preditivo do diâmetro do ventrículo esquerdo e da função ventricular como marcadores de IA avançada e prognósticos negativos.26 os cálculos necessários para estimar a VC, o VR e, como já mencionado anteriormente, o ORE obtido pelo método PISA apresentam diversas limitações.17 De fato, este estudo não pôde avaliar se o valor da IVT estava associado com a IA grave, independentemente do ORE, VR ou VC, pois a porcentagem de pacientes para os quais estes dados puderam ser obtidos não foi suficiente para realizar uma análise multivariada válida. Em contraste, a IVT não pôde ser estimada em apenas 3 dos 65 pacientes deste estudo devido a um alinhamento inadequado do jato da IA. Assim, a IVT mostrou ser um parâmetro reprodutível, que pode ser facilmente obtido e examinado na maioria dos pacientes, sendo capaz de fornecer informações valiosas para a estratificação da gravidade da IA.Apesar de serem métodos ecocardiográficos recomendados para determinar a gravidade da IA significativa,3 e a amostra do presente trabalho é composta sobretudo de pacientes com IA crônica. A baixa taxa de IA aguda neste estudo  impediu uma avaliação estatística viável de coorte da IA aguda. Esta situação poderia explicar a ausência de diferenças entre os valores do TMP dos grupos com IA moderada e grave.Destaca-se também que, apesar do TMP ter sido obtido para todos os pacientes que tiveram a IVT calculada, não foram encontradas diferenças significativas entre indivíduos com IA moderada e grave, o que impossibilitou a inclusão deste parâmetro na análise multivariada. Portanto, não foi possível avaliar o valor adicional da IVT com relação ao TMP. Diretrizes clínicas atuais sugerem que o aproveitamento do TMP é baixo em casos de IA crônica21 a IVT foi normalizada utilizando o comprimento diastólico.21 Todavia, existem poucos níveis de consistência na indexação da IVT em termos de FC. Acredita-se que estes achados reforçam a hipótese fisiopatológica de que uma IVT menor esteja associada a uma IA mais grave, independentemente da FC.Os resultados deste estudo também sugerem que a associação entre a IVT baixa e a IA grave não parece ser significativamente afetada por variáveis hemodinâmicas, tais como a FC e a PAD. Se outros estudos fundamentarem este comportamento de relacionamento, o uso da IVT poderá alcançar uma grande variedade de pacientes. No entanto, considera-se que a relação entre a IVT e a gravidade da IA não seria significativamente alterada por estas variáveis hemodinâmicas devido à falta de valores extremos. Ressalta-se que uma tendência de PAD mais baixa foi identificada em pacientes com IA grave e que pacientes com fibrilação atrial foram excluídos. Assim, considerando que a FC é um determinante temporal para a IVT da IA, a IVT indexada por FC também foi calculada para normalizar o valor da IVT e aprofundar o estudo da sua relação com a gravidade da IA. Além disso, a FC foi correlacionada inversa e significativamente com a IVT da IA. A relação entre esta nova variável e a gravidade da IA foi não apenas mantida, mas se mostrou mais forte e independente do DDFVE e da FEVE . Em outros estudos, como o de Zarauza et al.,28 Além disso, a falta de um método padrão-ouro impossibilitou uma avaliação mais precisa do valor da IVT. Ainda, os intervalos de valores da IVT obtidos fizeram com que o cálculo de um ponto de corte válido se tornasse impreciso. Assim, o baixo número de pacientes incluídos impediu uma validação transversal da IVT mensurada, tornando difícil chegar a conclusões sólidas. Por fim, não foi realizado acompanhamento clínico da amostra, o que impossibilita saber se o valor da IVT tem implicações clínicas ou prognósticas.Este estudo apresenta diversas limitações. Primeiro, este é um estudo unicêntrico que não analisou pacientes com IA e fibrilação atrial ou prótese valvar; portanto, o valor da IVT aórtica nestas subpopulações é desconhecido. Segundo, a IVT foi obtida por Doppler e, consequentemente, está sujeita às limitações desta técnica. Ademais, as análises incluíram apenas pacientes com IA moderada ou grave, em uma tentativa de evitar uma possível subestimação da medição da IVT de jatos regurgitantes leves de baixa densidade; assim, a eficácia da IVT em determinar a gravidade da IA leve permanece incerta. ORE, VR e VC não puderam ser obtidos para todos os pacientes, em parte pela natureza retrospectiva do presente trabalho, impedindo a avaliação do valor da IVT em relação a estes parâmetros na previsão de IA grave em uma análise multivariada. Nenhuma outra técnica exploratória, como ecocardiograma transesofágico, ultrassonografia 3D ou ressonância magnética cardíaca, foi realizada para investigar mais profundamente a gravidade da IA ou o mecanismo de regurgitação.A IVT da IA é um parâmetro ultrassonográfico facilmente obtido e reprodutível que parece estar associado com a gravidade da IA. Mais estudos são necessários para avaliar se este parâmetro é capaz de fornecer informações diagnósticas e prognósticas adicionais para pacientes com IA e se ele é útil em outras situações clínicas, como em casos de fibrilação atrial e em indivíduos com prótese valvar. 1 Typical management of the condition involves a combination of clinical signs and symptoms and data collection through complementary testing. Echocardiography is a key tool for the diagnosis and quantification of AR,2 and its proper interpretation requires an approach integrating qualitative, semiquantitative, and quantitative measures and parameters.4 However, these parameters are not exempt from limitations.3Aortic regurgitation (AR) is one of the most common valvular disorders in the developed world.5 In patients with AR, the VTI is multiplied by the aortic effective regurgitant orifice (ERO) to calculate the regurgitant volume (RV) (RV=EROxVTI).7 This parameter has demonstrated its effectiveness in determining AR severity, even though the ERO value is calculated using the proximal isovelocity surface area (PISA) method, which is known to have inherent limitations in patients with AR.9 Additionally, taking into account the aforementioned equation, patients with severe AR typically have larger RV2 and ERO values,10 but there is no evidence of the behavior of VTI in relation to AR severity.Velocity-time integral (VTI) is defined as the area measured below the Doppler velocity curve at any given point. In the case of AR, its value corresponds to the diastolic pressure gradient between the aorta and the left ventricle (LV).11 as well as reduced diastolic blood pressure (DBP).13 These pressure changes can pathophysiologically decrease VTI by reducing the pressure gradient between the aorta and LV. This study aimed to determine whether VTI is an echocardiographic marker of AR severity.Furthermore, patients with severe AR usually present increased end-diastolic pressure in the LVThis retrospective cross-sectional observational study was performed over ten months (from January to October 2016). All patients with AR who visited our cardiac imaging laboratory during this period were eligible to participate. Patients had to exhibit moderate to severe AR in a native (non-prosthetic) valve as well as sign an informed consent form to be included in the study. We excluded patients with atrial fibrillation or evidence of any type of arrhythmia, multiple or eccentric jets of AR. The study complied with the declaration of Helsinki and was approved by the ethics committee of our local research panel.14 The final arterial blood pressure was the average of the second and third values. Heart rate (HR) was determined at the moment of the measurement of the VTI of AR. All patients also had a blood test performed immediately after collection to determine the plasma creatinine level and calculate the glomerular filtration rate using the CKD-EPI (Chronic Kidney Disease – Epidemiology Collaboration) formula.15 The blood test analyzer used was a PE Chemistry .We gathered the following demographic and clinical information from all study participants: age, gender, history of arterial hypertension, dyslipidemia, diabetes mellitus, and smoking habits. Any type of antihypertensive, hypolipidemic, or antiarrhythmic drugs that the subjects were taking at the time of their inclusion in the study was also recorded. During the echocardiogram, the height and weight of each patient were collected, and three arterial blood pressure measurements were taken after 5 minutes of rest, using an M6 Comfort HEM-7221-E8  blood pressure monitor – validated through Dabl®Educational Trust and British Hypertension Society protocols –, following the European Society of Hypertension/European Society of Cardiology (ESH/ESC) recommendations.16 Both thickness and diameter were determined in M-mode with proper alignment whenever possible; otherwise, measurements were made in 2D. The measurement of the VTI of AR flow was taken using continuous Doppler readings from the view with the best alignment with the regurgitant jet, mainly the apical 5-chamber view , left ventricular end-systolic diameter (LVESD), and left ventricular ejection fraction (LVEF), in accordance with recommendations from the American Society of Echocardiography.er view    or the 19 Reliability analyses using kappa statistics (κ) defined the consistency between the two echocardiographers regarding AR severity (moderate or severe). Baseline differences between moderate or severe AR patients were assessed by unpaired Student’s t -test or Mann–Whitney U test for continuous variables and the χ2test for categorical variables. Logistic regression analysis evaluated the association between each baseline variable and severe AR. Multivariate logistic regression models determined the variables independently associated with severe AR. The variables included were those with p<0.05 in the univariate analysis, excluding RV, ERO, and VC, as they were not available for all patients and could cause overfitting. Model performance for predicting severe AR was evaluated by calibration (Hosmer-Lemeshow statistic) and discrimination (C-index) measures, both internally validated using the bootstrap resampling technique. The association between the VTI of AR and its severity was explored through multivariate analysis regardless of HR and DBP. We evaluated the relationship between VTIi and AR severity with a new logistic regression analysis. Confidence intervals (95%CI) were provided when appropriate. All probability values were 2-sided, and p-value<0.05 was statistically significant. Statistical analysis was performed using the SPSS software, v.18.0 .We tested all variables for normal distribution using the Kolmogorov-Smirnov test. Continuous variables with normal distribution were expressed as mean±standard deviation (SD), and those with skewed distribution as median [interquartile range (IQR)]. Categorical variables were expressed as percentages. Correlations were studied through Spearman’s or Pearson’s method, as appropriate. Inter-rater variability for AR severity quantification was determined by the intraclass correlation coefficient and Bland-Altman plots.The original sample consisted of 65 patients with moderate or severe native AR in sinus rhythm. Proper Doppler alignment of the regurgitant jet could not be obtained for three patients, who showed very eccentric jets, and were thus excluded. Out of the remaining 62 participants, 40 (64.5%) presented moderate AR, and 22 (35.5%) had severe AR. Acute AR was diagnosed in 4 patients (6.5% of the sample). The consistency among the quantification determined by the two echocardiographers was κ=0.83. All patients included were Caucasian. p)=-0.408, p=0.001]. Patients with severe AR presented lower LVEF, higher LVEDD and LVESD, as well as a larger ERO, RV, and VC. However, the proper measurement of these parameters was only possible in 62.9% of the sample for ERO, 67.7% for RV, and 72.6% for VC. We underline that we identified no statistically significant association between AR severity and PHT, even though we detected a trend for it.As shown in p=0.905, p<0.001) and LVEDV , respectively. We also excluded ERO, RV, and VC from the multivariate analysis as they could not be obtained for all patients due to poor ultrasound window or difficulty in measuring. This model showed greater discrimination  and an accurate calibration .In the bivariate analysis   , VTI waOn the other hand, since HR and DBP could pathophysiologically influence the VTI measurement , the association between VTI and AR severity was assessed adjusting for HR and DBP. VTI was also inversely related to AR severity, irrespective of these factors . Finally, the VTIi of AR also showed an inverse association with AR severity    and act20This study suggests that the VTI of AR can be used as a marker of severity in patients with significant AR, considering that estimating severity through echocardiography is a difficult process involving the integration of several different tests and parameters.7 and an indirect relationship can be found between ERO and VTI (ERO=RV/VTI).10 More severe AR presents a larger ERO and RV, but the behavior of VTI is unknown. In this study, the VTI of the aortic regurgitant flow was inversely associated with AR severity. The scientific evidence available corroborating this relationship is scarce. Zarauza et al.21 published a study that assessed the value of VTI of AR, amongst other parameters, in a sample of 43 patients with moderate to severe AR.21 Their findings were similar to ours . However, in the study by Zarauza et al.,21 the differences between VTI in severe and moderate AR did not reach statistical relevance. The difference in sample size for patients with moderate AR (15 vs. 40) could explain the lack of a significant result. To the best of our knowledge, no other study has assessed the value of VTI as an indicator of AR severity.Effectively, ERO by the PISA method works as a parameter for the stratification of AR severity,24 In our opinion, this aspect reflects an appropriate and rigorous methodology for measuring these parameters. This study found that the relationship between VTI and AR severity did not depend on echocardiographic variables, such as left ventricular diameters, volumes, or ejection fraction. This result could potentially support the use of VTI as an indicator in most echocardiographic scenarios involving AR and sinus rhythm.A remarkable aspect of the present study is the direct association between AR severity and end-diastolic and end-systolic diameters and volumes, in addition to the inverse relationship to LVEF. These findings are consistent with available scientific evidence, which supports the predictive role of left ventricular diameter and ventricular function as markers of advanced AR and negative prognoses.26 the calculations necessary to estimate VC, RV, and, as we previously mentioned, ERO obtained by PISA present several limitations.3,8,9,17 In fact, this study could not evaluate whether the VTI value was associated with severe AR, regardless of ERO, RV, or VC, as the percentage of patients from whom this data could be obtained was not enough to perform a valid multivariate analysis. In contrast, VTI could not be estimated in only 3 of the 65 patients of this study due to improper alignment of the AR jet. Thus, VTI has proven to be a reproducible parameter that can be easily obtained and examined in most patients and could provide valuable information for the stratification of AR severity.Despite being echocardiographic methods recommended for determining the severity of significant AR,3 and the sample of the present work consists mainly of chronic AR patients. The low rate of acute AR in the present study (6.5%) precluded a feasible statistical evaluation of the acute AR cohort. This issue could explain the lack of differences in the PHT values between the moderate and severe AR groups.We also emphasize that although PHT was obtained for all patients who had their VTI calculated, we found no significant differences between individuals with moderate and severe AR, which prevented the inclusion of this parameter in the multivariate analysis. Therefore, we could not assess the additional value of VTI with respect to PHT. Current clinical guidelines suggest that the usefulness of PHT is low in cases of chronic AR,21 VTI was normalized using the diastolic length.21 However, there are few levels of consistency throughout the indexing of VTI in terms of HR. We believe that these findings support the pathophysiological hypothesis that a smaller VTI is associated with a more severe AR, regardless of the HR.Our results also suggest that the association between lower VTI and severe AR does not seem to be significantly affected by hemodynamic variables, such as HR and DBP. If other studies supported this relationship behavior, the use of VTI could reach a wide variety of patients. However, we consider that the relationship between VTI and AR severity could not be significantly changed by these hemodynamic variables due to a lack of extreme values. We highlight that we found a tendency for lower DBP in patients with severe AR and that we excluded patients with atrial fibrillation. Thus, since HR is a temporal determinant for the VTI of AR, we also calculated the VTI indexed by HR to normalize the VTI value and further study its relationship to AR severity. Additionally, HR correlated significantly and inversely with AR VTI. The relationship between this new variable and AR severity was not only maintained but proved to be stronger and independent of LVEDD and LVEF . In other studies, such as the one by Zarauza et al.,28 Moreover, the lack of a gold standard method precluded a more accurate assessment of the VTI value. Otherwise, the ranges of the VTI values obtained made inaccurate the calculation of a valid cut-off point. Thus, the small number of patients included prevented a cross-sectional validation of the VTI measured, making it difficult to reach solid conclusions. Lastly, we performed no clinical follow-up of the sample, making it impossible to know whether the VTI value has any prognostic or clinical implications.Our study presents several limitations. First, this is a single-center study that did not analyze patients with AR and atrial fibrillation or prosthetic valves, and thus the value of the aortic VTI in those subpopulations is unknown. Second, the VTI was obtained by Doppler imaging, and, therefore, it is subject to the limitations of this technique. Additionally, our analyses only included patients with moderate or severe AR in an attempt to avoid a potential underestimation in the VTI measurement of low-density mild regurgitant jets; thus, the usefulness of VTI in determining the severity of mild AR remains unclear. ERO, RV, and VC could not be obtained for all patients, partially due to the retrospective nature of the present paper, preventing the assessment of the VTI value with respect to these parameters in predicting severe AR in a multivariate analysis. No other exploration techniques, such as transesophageal echocardiogram, 3D ultrasound, or cardiac magnetic resonance, were performed to study the AR severity or the mechanism of regurgitation in depth.The VTI of AR is an easily obtainable and reproducible ultrasound parameter that seems to be associated with AR severity. Further studies are necessary to evaluate whether this parameter is capable of providing additional diagnostic and prognostic information for patients with AR, and whether it is useful in other clinical scenarios, such as atrial fibrillation and in individuals with prosthetic valves.


Developing new varieties in fruit and tea breeding programs is very costly and labor-intensive. Thus, establishing a variety discrimination system is important for protecting breeders’ rights and producers’ profits. Simple sequence repeat (SSR) databases that can be utilized for both next-generation sequencing (SSR-GBS) and polymerase chain reaction–capillary electrophoresis (PCR-CE) would be very useful in variety discrimination. In the present study, SSRs with tri-, tetra- and pentanucleotide repeats were examined in apple, pear and tea. Out of 37 SSRs that showed clear results in PCR-CE, 27 were suitable for SSR-GBS. Among the remaining markers, there was allele dropout for some markers that caused differences between the results of PCR-CE and SSR-GBS. For the selected 27 markers, the alleles detected by SSR-GBS were comparable to those detected by PCR-CE. Furthermore, we developed a computational pipeline for automated genotyping using SSR-GBS by setting a value “α” for each marker, a criterion whether a genotype is homozygous or heterozygous based on allele frequency. The set of 27 markers contains 10, 8 and 9 SSRs for apple, pear and tea, respectively, that are useful for both PCR-CE and SSR-GBS and suitable for automation. The databases help researchers discriminate varieties in various ways depending on sample size, markers and methods. Fruit and tea breeding requires tremendous cost and time to release varieties because of their long juvenile stage and large plant size . Once elSimple sequence repeats (SSRs) are neutral markers that are used mainly in population genetics as well as in conservation ecology and phylogenetic analysis ,7,8,9. TRecently, some methods that apply NGS techniques for genotyping SSRs, called SSR-GBS  or SSR-sMalus domestica Borkh.), pear (Pyrus pyrifolia Nakai.) and tea (Camellia sinensis (L.) O. Kuntze).To overcome these disadvantages of SSRs, databases that can be utilized for both PCR-CE and SSR-GBS would be very helpful for use in variety discrimination. Depending on the objective, researcher preference and sample size, researchers can select a suitable way to identify genotypes by using these databases. The objective of the present study was to select SSR markers that are suitable for both PCR-CE and SSR-GBS and to validate their repeatability in SSR-GBS. In order to develop automatic allele calling and to create a pipeline that is easy to implement, we mainly used tri-, tetra- and pentanucleotide repeats that do not produce stutter bands. To assess stability and repeatability, we replicated the SSR-GBS analysis in three different species: apple (C. sinensis var. sinensis ‘Shuchazao’ (CSS-SCZ) ACACTCTTTCCCTACACGACG) and P7 (CAAGCAGAAGACGGCATACGAGAT[Index]GTGACTGGAGTTCAGACGTGT) in which Illumina flow-cell binding sites and two different indexes of 8 bp were contained. The primers used for this experiment are listed in 2, pH 8.5; Promega), 1 µL P5 and P7 primers (1 μM) 3 µL H2O and 1 µL of the first PCR products. PCR reactions included the following steps: an initial denaturation of 95 °C for 5 min followed by 15 cycles of 94 °C for 30 s, 60 °C for 1 min and 72 °C for 30 s. This was followed by a final extension of 10 min. All of the second PCR products were mixed equally in a single tube and purified using AMPure XP beads  following the Agencourt AMPure XP PCR Purification protocol. The library was sequenced using PE 300-bp sequencing on an Illumina MiSeq platform .SSR-GBS was performed based on the methods described in previous reports with slight changes in sequence data analysis ,34. WhenThe reads from Illumina MiSeq were demultiplexed to each variety based on the index sequences using the Illumina system, and the paired fastq files of each variety were obtained. We used flash2  to mergeTo construct a database useful for both SSR-GBS and PCR-CE, we thoroughly compared the genotypes obtained by SSR-GBS with those obtained by PCR-CE and vice versa. First, the markers that showed fewer than 50 average reads in SSR-GBS were discarded. The correspondence of each allele of each marker obtained by SSR-GBS to the alleles obtained by PCR-CE was confirmed manually to identify cases of allele dropping in SSR-GBS. If allele dropping was found with a marker, that marker was not included in the database for SSR-GBS.In previous studies of SSR-GBS, allele calling was performed based on whether the frequency of the first allele exceeded 0.9 or on manual evaluation . However