C. maxima × C. mochata). We used three different scions: the apical meristem (AM), one-node (1N), and two-node (2N) branches of diploid, triploid, and tetraploid watermelon plants. We then evaluated the effects of grafting on plant survival, some biochemical traits, oxidants, antioxidants, and hormone levels at different time points. We found significant differences between the polyploid watermelons when the 1N was used as a scion. Tetraploid watermelons had the highest survival rates and the highest levels of hormones, carbohydrates, and antioxidant activity compared to diploid watermelons, which may explain the high compatibility of tetraploid watermelons and the deterioration of the graft zone in diploid watermelons. Our results show that hormone production and enzyme activity with high carbohydrate content, particularly in the 2–3 days after transplantation, contribute to a high survival rate. Sugar application resulted in increased carbohydrate accumulation in the grafted combination. This study also presents an alternative and cost-effective approach to producing more tetraploid and triploid watermelon plants for breeding and seed production by using branches as sprouts.Seed production for polyploid watermelons is costly, complex, and labor-intensive. Tetraploid and triploid plants produce fewer seeds/fruit, and triploid embryos have a harder seed coat and are generally weaker than diploid seeds. In this study, we propagated tetraploid and triploid watermelons by grafting cuttings onto gourd rootstock ( The seedless watermelon [triploid (3n)] is produced by crossing between a tetraploid (4n) seed parent with a seeded watermelon [diploid (2n)]2. Tetraploid induction can be achieved using various methods, such as applying aqueous chemical solutions  to the growing tips of diploid seedlings, or by soaking diploid seeds before germination3. However, these chemicals are toxic, which reduces the success rate4. Herbal grafting is used commercially because it offers a wide range of essential benefits such as enhancing the resistance to biotic and abiotic stresses along with yield improvement7. In contrast, soil quality degrades over time due to successive land use, while stress and disease occur more frequently, thereby improving plant growth, and increasing yields8. Successful grafting is a complex biochemical and structural process that involves initial wound reaction, callus formation, cambium formation, and the development of a functional vasculature between scion and rootstock9. All of these steps can shape the future of a grafted plant10. However, there are no general rules about how these treatments affect incompatibility responses in tolerance reactions12. To date, the causes and underlying mechanisms of grafting incompatibility remain elusive, and there are no reports on genes associated with grafting incompatibility14. More research is needed to fully understand graft compatibility and incompatibility mechanisms16.Seedless watermelon varieties are preferred and accepted by consumers, and have a higher price and better quality than seeded watermelons (2n)17. Pina et al.18 found that reduced auxin and lignification, which are associated with high phenols in incompatible grafts, could indicate weak graft junctions, reactive oxygen species (ROS)22, or hormone imbalance24. IAA and cytokinin play vital roles in regulating rootstock/scion interactions25, and are necessary for vascular bundle regeneration at the graft union27, the differentiation of vascular tissues and wound healing31. There are three main classes of auxin-responsive genes: the GH3, Aux/IAA, and SAUR gene families35. Liu et al.36 found that ARF1, ARF8, GH3, and IAA4 expression levels were shown to be negatively correlated with growth vigor and IAA content. Also, the differential expression of KO1 and GA2OX1 in grafted trees had an impact on the metabolism of GA.Graft incompatibility in fruit trees occurs due to the accumulation of various factors37. The second and third days after grafting are crucial for the healing process38. In shoots of apple grafted on a dwarf rootstock, Li and colleaguesdiscovered that the expression of the gene PIN1, which is related to polar auxin transport, was markedly reduced39. The alteration in gene expression led to a decrease in the top-down polar transport of indole-3-acetic acid (IAA), which caused inadequate delivery of IAA to the apple roots.From Ren and colleages, it was discovered that CmRNF5 and CmNPH3L are variably expressed across compatible and incompatible graft unions throughout graft development of cucumber/pumpkin graft’s growth19. These two genes may be associated with transplant compatibility/incompatibility responses based on the difference in expression of the two genes seen in the scion and various compatibility records. The results showed that both genes are affected by stress. The accumulation of reactive oxygen species (ROS) leads to cell death, and oxidative damage is due to the imbalance between the production of antioxidants (AOX) and ROS41. Increasing the activity of defense enzymes such as peroxidase (POD) and catalase (CAT) can scavenge ROS in plants and improve the resistance of plants to stress43. Guaiacol peroxidase (POX) and CAT convert H2O2 to H2O44. So, the differences between AOX and ROS during the healing process could be used as a rapid mechanism to verify incompatibility45. Lignin is abundant in woody plants and primarily contributes strength to the cell wall such that reduced lignin would counteract strong graft union16. Most antioxidant enzyme genes were upregulated in leaves from trees grafted onto red tangerine, resulting in higher POD activity36. In addition, studies have found differences in gene expression studied rootstock/sprout combinations of sweet cherry46 and grape47.During the healing process of grafting, the grafted plants are exposed to various stresses, such as injuries or wounds, total darkness, and high humidity49. The development of graft union in the grafting compound primarily depends on the levels of carbohydrates present in the rootstock and scion during the grafting process. Higher levels of carbohydrates, along with auxins and cytokines, are crucial for the formation of effective callus. Interactions between rootstock and scion cultivars of watermelon for carbohydrate utilization can affect the starch degradation that occurs throughout the grafting process; the survival rate was positively correlated with increased starch content49.Furthermore, carbohydrates play an important role in the cellular activities of plants by providing energy50. Likewise, studies on grape, macadamia, lychee, avocado, and watermelon seedlings indicated that increasing starch content in the shoot has a positive correlation with successful grafting53.Previous research on perennial crops has shown that increasing carbohydrate content can increase the success rate of grafting. For instance, in grapes, there is a positive correlation between callus formation and carbohydrate content in grafted grapes, leading to higher survival rates of the transplanted materialThe current research aimed to study the effect of genome duplication on graft compatibility by comparing the factors and parameters that lead to graft compatibility or incompatibility. This study provides molecular and physiological level information for the compatibility mechanism in polyploid watermelons and thus explains the compatibility mechanism in polyploid watermelons using branches as scions for plant propagation. Three different branches were taken from mother plants and grafted onto squash rootstock to study compatibility and the effect of sucrose application on graft compatibility. Grafting branches will help breeders and seed producers save time and money by using an asexual method of increasing plant numbers.C. maxima × C. mochata) during two consecutive seasons (First season: August 2021 and Second season: March 2022). Statistical analysis showed significant differences between diploid, triploid and tetraploid scions when 1N was used as a scion. The combined analysis for two seasons gave 45.45, 55.45, and 78.03% in diploid, triploid and tetraploid watermelon, respectively. In the first season, grafting by AM gave the highest survival rate of 93.3, 96.67, and 96.67% in the first season and 96.67, 100, and 100% in the second season in diploid, triploid, and tetraploid watermelons, respectively. However, no significant differences were observed between polyploid scions. Also branches with two nodes (2N) showed no significant differences between polyploids in terms of survival rate of 86.67, 83.33, and 83.33% in the first season and 90, 93.33, and 96.67% in the second season in diploid, triploid, and tetraploid watermelons, respectively  exerted a significant impact on the IAA content in the graft combination at all stages 0, 3 and 15 from DAG , higher SOD activity was observed in tetraploid and triploid watermelons compared to diploid watermelons Fig. . The actnts Fig. .We obserThe lignin content was significantly different between diploid and tetraploid watermelon plants in both seasons Fig. . The ligWe observed significant differences in phenol content in diploid and tetraploid watermelons in both seasons at 3 DAG Fig. . The conSimilarly, we observed significant variations in starch content in ploidy-level grafted watermelons in the first season, but no significant differences were observed in the second season Fig. . The resThe heat map (A and B) in the first and second seasonal visualization of all hormones and biochemicals Fig.  showed a2O2, starch, POD, SOD, lignin, phenols, ZR, IAA, and CAT selected from Arabidopsis thaliana, Citrullus colocynthis, Cucumis melo, Cucumis sativus, Cucurbita maxima, Cucurbita moschata, Cucurbita pepo, Luffa aegyptiaca and Momordica charantia, as a query to identify homologous genes in watermelons. Homologous genes in watermelons are summarized in , phenols, lignin, and starch were checked and drawn phylogenetic trees at three stages 0, 3, 15 DAG , and WM-ZR-1 (Cla97C05G105550), had higher expressions controlling IAA and ZR signaling in tetraploid watermelon followed by triploid and diploid watermelon during the grafting process in both seasons. WM-POD-1 (Cla97C07G135790), WM-CAT-1 (Cla97C08G152180), and WM-SOD-1 (Cla97C04G071940) controlling POD, SOD, and CAT synthesis had a higher expression in tetraploid as compared to triploid and diploid watermelon. WM-H2O2-1 (Cla97C10G195960) controlling H2O2 production, had a lower expression level in tetraploid watermelons than in triploid and diploid watermelon plants during the grafting process. Genes regulating starch and lignin contents in watermelon, including WM-Starch-1 (Cla97C01G017330), WM-Lignin-1 (Cla97C07G137860), controlling starch and lignin production, had higher expressions in tetraploid watermelon as compared to triploid and diploid watermelon confirming their active roles in starch and lignin accumulation at all the time points of sampling. Among the genes controlling phenol contents, WM-Phenol-1 (Cla97C09G171570) ion had higher expression in triploid and diploid watermelon as compared to tetraploid watermelon during the grafting process.Expressions of genes regulating CAT, POD, SOD, HDAG Fig. . The PCRSignificant variations between polyploids were observed after sucrose application Fig. . The comThese results indicate that the drench applications of 2% sucrose on rootstocks seedlings before grafting could increase the survival rate when grafted by 1 N.An increase in starch accumulation was observed with increasing concentration of sucrose application. Starch accumulation in grafted watermelons with different ploidy level 3 and 15 DAG was highest in plants given 3% sucrose solution than in plants given 2% sucrose solution Fig. .Figure 9Compared to the control, the application of 3% sucrose led to the highest accumulation of starch. At 0, 3, and 15 days of grafting, the starch contents in the graft combinations were 131.00, 125.45, and 142.27 mg/g FW in diploids, 80.58, 85.19, and 76 mg/g FW in triploids and 168.83, 202.75, and 181.42 mg/g FW in tetraploids in the first season, respectively. While, at 0, 3 and 15 days of grafting in second season, starch contents in the graft combinations were 61.69, 105.86, and 116.9 mg/g FW in diploids, 79.23, 88.26, and 105.09 mg/g FW in triploids, and 196.35, 223.27 and 232.24 mg/g FW in tetraploids, respectively. On the other hand, the highest survival rates among all polyploids were observed with 2% sucrose application. Interestingly, the accumulation of starch in the graft combination at stage 3 DAG  was significantly higher in tetraploids than in triploids and diploids, i.e. 2.13 and 1.77-fold higher than in diploids in the first and second seasons, respectively, and 1.51-fold greater than triploid in the first and second seasons, respectively, results indicate that sucrose led to an increase in starch accumulation in grafted plants, thereby increasing survival rates in polyploid watermelons.56, mango58, and peach59, etc. to achieve good survival and avoid seed production problems. Here we grafted plants using branch cuttings as scion for successful vegetative propagation of watermelons with different ploidy levels. Triploid watermelon seeds are produced by cross-pollination between diploid and tetraploid seeds, but tetraploid seed production is arduous60. So, it is important to find a more economical way to increase the number and quality of triploid seeds61. In this study, we tested three various shoot parts of mother plants as scion,  to increase the number of mother plants to be clonally propagated by grafting technique We determined the content of hormones and antioxidants in the graft combination at 0, 3 and 15 DAG, the most critical time in the healing process is 2–3 DAG. During the healing stage, the stress is maximal 37, along with an increase in hormone and antioxidant levels leading to graft compatibility38. Our results showed a higher survival rate  content in incompatible combinations may then affect the differentiation of xylem and phloem, as well as lignification67. We compared the IAA and ZR contents in the graft union between diploid, triploid, and tetraploid watermelon plants  and 15 DAG, these results were agreement with Cookson et al.68, Schaller et al.69, and Melnyk et al.38.Plant hormones play important roles in plant growth, development, and response to biotic and abiotic cues and vascularization in the graft junction15. In this study els Fig. . It has 81. Phenols contribute to the elimination of ROS82. In our results, the content of phenols was higher at all stages than in diploid and triploid plants at all stages, thus leading to incompatibility21, and a significant decrease in phenol content was observed at later stages of grafting 15 DAG  to the rootstocks led to an increase in the accumulation of starch in the plant before grafting, and this led to an increase in the survival rate, these results were identical with Dabirian and Miles49. We applied sucrose to the rootstock seedlings and a higher survival rate was observed in the case a 2% sucrose application followed by a 3% sucrose application in polyploid watermelon. The accumulation of starch in the graft combination was positively increased with increasing concentration of sucrose in the solution, as the treatment had the highest rate of accumulation of starch at a concentration of 3%, followed by 2% compared to the control. These results were identical with Dabirian and Miles49, who conducted a similar experiment to increase the survival rate in watermelons grafted by the splice grafting method. The accumulation of starch in the graft combination at stage 3 DAG  was significantly higher in tetraploids than in triploids and diploids. It was 2.13 times higher than diploid and 1.58 times higher than triploid. These results could explain the increase in survival rate by increasing the concentration of sucrose in the solution and could explain the increase in survival rate in tetraploids. It was higher than triploid and diploid due to its ability to store the highest rate of starch over triploid and diploid. These results are consistent with Bartolini et al.50, who suggested that higher carbohydrate levels in grafted tissues could lead to successful grafting. According to recent results, the sucrose application was taken up by rootstock seedlings, leading to higher starch accumulations in the grafted plants, leading to an increase in survival rates in polyploid watermelons. Carbohydrates are just as important hormones in the process of compatibility and callus formation, so are carbohydrates53. And it has been proven by the experiment that increasing the percentage of carbohydrates led to an increase in the rate of grafting survival49.The carbohydrates provide energy in the plant and the cotyledons are a source of carbohydrates in the seedlingsOverall, compatibility is a phenomenon that occurs through a combination of factors, including higher IAA, starch contents, and POD, CAT and SOD activities. All of these factors are more or less interrelated; this makes it easier for the plant to survive.Cla97C05G092790 might play an important role in graft compatibility in tetraploid watermelon. The expressions of genes linked to POD, SOD, CAT, and starch increased at 3 DAG. These findings are similar to Ren et al.19 in cucumber and Liu et al.36 in citrus. The increased expression of Cla97C05G092790 leads to an increase in IAA signaling in tetraploid plants. Similarly, we observed higher expressions of genes linked to POD , SOD , CAT (Cla97C08G152180), and starch Cla97C01G017330 at 3 DAG that leads to a higher compatibility. While expression of a gene linked to H2O2 (Cla97C10G195960) at 3 DAG decreased significantly. This study assumes that the survival rate of tetraploids is high due to high accumulation of hormones, antioxidants and starch and lower H2O2.During the grafting process, physiological changes lead to graft compatibility. It is important to identify the key genes and mechanisms in grafted watermelon to understand graft compatibility. IAA, ZR, and antioxidants have higher activity during the grafting process. From the results we can assume that mimei), which is homozygous and genetically stable and passed the achievement appraisal of the Chinese Department of Agriculture in 1990 and won the second prize of science technology progress of the Department of Agriculture in 199184. Tetraploid, triploid, and diploid watermelons were grown for 60 days and used as mother plants. Branches were taken from these mother plants and grafted on squash interspecific (C. maxima × C. moschata) hybrid (Xijiaqiangsheng) widely used in China as a rootstock. Scions and rootstocks were obtained from the polyploid watermelon group—Zhengzhou Fruit research institute (CAAS) China. Our studies were complied with the relevant institutional, national, and international guidelines and legislation. The plant experiments were conducted according to local and national regulations and following Henan Joint International Research Laboratory of Fruits and Cucurbits Biological Science in South Asia and Zhengzhou Fruit research institute (CAAS)  regulations. All experiments were conducted in Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Henan Joint International Research Laboratory of Fruits and Cucurbits Biological Science in South Asia Zhengzhou, China. We have permission to collect the Watermelon (Citrullus lanatus L.) plant, and the source of plants from the polyploid watermelon group—Zhengzhou Fruit research institute (CAAS) China.Seedless watermelons are triploids (3n = 33) produced by crossing a tetraploid seed parent with a diploid (2n = 22) pollen parent. Tetraploid induction was done by applying colchicine to the growing apex of diploid seedlings. Polyploid seeds for one variety ] from the branch with one node (1N) were collected at three different stages 0, 3, and 15 days after grafting (DAG) for the determination of hormones, AOX, and RNA extraction. Each biological replicate sample from 30 plants was collected at three different stages, 0, 3, and 15 days after grafting (DAG). We collected 30 plants and considered them as one replicate. Samples were taken at 0 DAG as a control to study the grafting process development. Plants were cultivated in a growth chamber with 25–30 °C temperature and 60–85% humidity. The sensor in each experimental plot’s center was used to record temperature and humidity data .49. Sucrose solution was applied in the morning 2 and 4 days before grafting. Three replicates of 15 plants per treatment in the current experiment were maintained during two consecutive seasons. A randomized complete block design was used here with three replications and three biological replications.According to the protocol established by sucrose or water applications to rootstocks seedlings, they were applied as a soil drench43:Survival rates were determined after 15 days after grafting using the following formula25.Samples were taken as three biological replicates from the grafting combination (stems where scion and rootstock interlocked) at 0, 3, and 15 days after grafting (DAG). The contents of IAA and Zeatin Riboside (ZR) were measured by the Enzyme-Linked Immunosorbent Assay (ELISA) method . The determination of hormonal contents was performed as outlined by Mo et al.2O2 assay kit/YX-C-A400 for measuring Hydrogen peroxidase content at 415 nm wavelength  according to the manufacturer’s instructions. Three biological replications from grafting combination (stems where scion and rootstock interlocked) at 0, 3, and 15 DAG from three different plants for each replicate were collected for analysis. The activities of the antioxidant enzymes were expressed as a unit U g−1 FW sample.SOD assay kit/YX-C-A500 was used for the measurement of superoxide dismutase activity at 560 nm wavelength. CAT assay kit/BC0200 for measuring catalase assay at 240 nm wavelength, POD assay kit/YX-C-A502 for measuring peroxidase activity at 570 nm wavelength, and HBiochemicals were quantified by using the respective kits i.e., starch assay kit/YX-C-C400 for starch content estimation at 620 nm wavelength, lignin assay kit/YX-C-B636 for lignin content using 280 nm wavelength, and phenol assay kit/YX-C-A507 for total phenols content using 760 nm wavelength  according to the manufacturer’s instructions. Three biological replications from grafting combination (stems where scion and rootstock interlocked) at 0, 3, and 15 DAG from three different plants for each replicate were collected for analysis.Arabidopsis thaliana, Citrullus colocynthis, Cucumis melo, Cucumis sativus, Cucurbita maxima, Cucurbita moschata, Cucurbita pepo, Luffa aegyptiaca, and Momordica charantia were downloaded from http://www.ncbi.nlm.nih.gov/Genbank/, https://phytozome.jgi.doe.gov/pz/portal.html, http://cucurbitgenomics.org/organism/2, and http://www.uniprot.org/ were used as queries for protein blast analysis against the Watermelon Reference Genome Database (http://cucurbitgenomics.org/organism/21) v2. MEGA X software was used to draw phylogenetic trees, the ClustalW tool was used to align protein sequences, and the neighbor-joining method with 1000 bootstrap replicates was applied to construct phylogenetic trees89.The protein sequences of genes involved in IAA, ZR, antioxidants, lignin, phenols, and starch metabolism and transport in http://cucurbitgenomics.org/organism/1 and (2) ExPASy http://web.expasy.org/computepi/ databases. An online tool namely “Gene Structure Display Server (GSDS)”, a web-based bioinformatics tool was used for the display of genes structures90.Names of the 25 genes along with their accession numbers, genomic lengths, coding sequence lengths, protein sizes, and isoelectric points (pIs) and Mw (Da), were retrieved from two online tools, (1) According to the manufacturer’s instructions, total RNA was extracted from the grafting combination (stems where scion and rootstock interlocked) using RNA Kit . Samples from grafting combinations were taken at three stages . 1% agarose gel was used to check RNA degradation and contamination. RNA quality and integrity were checked via NanoDrop ND-1000 spectrophotometer  and an Agilent 2100 Bioanalyzer . Extracted RNA was used for the cDNA synthesis for RT-qPCR, with M-MLV Reverse Transcriptase .−ΔΔCt method91. Three independent biological replicates were used for gene expression analysis; Actin “cla016178” was used as a reference gene55.RT-qPCR of genes linked to IAA, ZR, antioxidants, lignin, phenols, starch metabolism, and the transport was performed in grafted watermelon plants from the grafting combination (stems where scion and rootstock interlocked) at 0, 3, and 15 DAG Fig. . Primer Data were statistically analyzed using XLSTAT PEARSON Edition (XLSTAT Version 2014.5.03) developed by Addinsoft. Excel for Microsoft 365 package version 16.0.14026.20246 used to draw all pictures. Analysis of variance (ANOVA) confirmed the significant variations among the split-plot design treatments with three replications. Duncan’s multiple range test (DMRT) compared the means sets at a 5% probability level.The current study concludes that vegetative propagation by branch grafting could be used to propagate triploid and tetraploid watermelons with high survival rates, making seed production easier and cheaper. An enigma of graft compatibility has been addressed here. Hormone, starch content and antioxidant activities were higher in tetraploids than in diploids due to genome duplication that produced high compatibility and high transplant survival rates. In addition, expression patterns of genes associated with biochemical and antioxidants also indicate their important role in the graft compatibility mechanisms. Using branch grafting can be an excellent alternative to encourage vegetative propagation in tetraploid watermelons. These results add important information to our existing knowledge of watermelon compatibility, ultimately aiding in vegetative propagation and breeding watermelon cultivars with desirable traits.Supplementary Information.


Coronary artery bypass grafting (CABG) is the gold standard procedure for multi vessels and left main coronary artery disease. The prognosis and survival outcomes of CABG surgery are highly dependent on the patency of the bypass graft. Early graft failure which can occur during or soon after CABG remains a significant issue, with reported incidences of 3–10%. Graft failure can lead to refractory angina, myocardial ischemia, arrhythmias, low cardiac output, and fatal cardiac failure, emphasizing the importance of ensuring graft patency during and after surgery to prevent such complications. Technical errors during anastomosis are among the leading causes of early graft failure. To address this issue, various modalities and techniques have been developed to evaluate graft patency during and after CABG surgery. These modalities aim to assess the quality and integrity of the graft, thus enabling surgeons to identify and address any issues before they lead to significant complications. In this review article, we aim to discuss the strengths and limitations of all available techniques and modalities, with the goal to identify the best modality for evaluating graft patency during and after CABG surgery. Despite the advancement in percutaneous coronary intervention (PCI) technology, CABG surgery is still the gold standard procedure for left main and complex multi vessels coronary artery disease . Due to Conventionally, the quality and flow of the graft were checked with naked eyes before anastomosis, as well as feeling the flow in the graft with digital palpation, checking the patient’s hemodynamic condition, new ECG changes for ischemia, and new heart wall motion abnormalities with echocardiography after anastomosis . UnfortuInvasive coronary angiography is the gold standard investigation for graft quality assessment during surgery ,27. All Intraoperative fluorescence imaging is an intraoperative invasive angiography-like modality but uses fluorescent indocyanine green (ICG) dye. This is less invasive compared with catheter-based angiography. The dye is injected through the central vein and images of grafts, anastomosis, and native coronary vessels are achieved. ICG dye has been in clinical use for many decades but its use in quality assessment in CABG surgery started at the beginning of the 21st century ,30,31. DEven though coronary angiography is the gold standard and most reliable method for intraoperative graft patency, when considering the cost, availability, additional surgery time, and risk, it may not be a very practical and feasible way of assessing graft patency. Assessing the patency of the graft through a transient time ultrasound is a noninvasive, simple, and reliable method of flow measurement of the graft while the patient is still in the OR . TTFM waHigh-frequency epicardial echocardiography (HEE) was developed for the assessment of morphological and functional information of the graft and anastomosis quality. Several clinical reports have established its efficacy intraoperatively ,45,46,47On the contrary, Hol et al. conducted a study where they compared the measurement of graft diameters and graft quality assessment using epicardial ultrasonography with those measured using intraoperative angiography. They found poor correlations between the two methods for graft diameter. However, epicardial ultrasonography detected 13% of the abnormal grafts while ICA found 23% of the abnormal grafts. The specificity, sensitivity, PPV, and NPV for HEE compared with ICA were 90%, 22%, 40%, and 79%, respectively. The authors concluded that although epicardial ultrasonography was useful in assessing graft quality intraoperatively, angiography was superior in identifying grafts that require revision. Therefore, epicardial ultrasonography has the potential of assessing graft morphology but its ability to predict graft that needs revision should be further evaluated in comparative studies .Transesophageal echocardiography (TEE) was one of the accepted modalities used for the assessment of grafts intraoperatively. Several studies by Hiroshima University Hospital performed an intraoperative assessment of grafts by using TEE ,49,50. IIn a retrospective study of 51 patients by Kuroda et al. who underwent LITA-LAD grafting evaluated by TEE intraoperatively and were examined with ICA postoperatively , the resIt is crucial to monitor the graft after CABG surgery because life expectancy and quality of life are typically dependent on the quality of the bypass graft. According to a study, the internal mammary artery occlusion rate in the first year after surgery is 5.7% in men and 3.4% in women . SaphenoAs discussed for intraoperative graft quality assessment, we have multiple modalities to assess graft quality postoperatively as well. Different tools for assessment are invasive angiography, computed tomography (CT), magnetic resonance angiography (MRA), and transthoracic echocardiography. The available studies comparing postoperative noninvasive graft assessment modalities with ICA are listed in Angiography is the investigation of the standard reference for the evaluation of postoperative graft quality and patency and is routinely used for follow-up graft assessment ,70,71,72As mentioned earlier, invasive angiography has its limitations, which have led patients to favor noninvasive procedures, and they can be easily persuaded to undergo such procedures. Healthcare workers are trying to achieve the best possible results of angiography with noninvasive techniques. CTA represents an effort in this direction, with various types of CTA available to conduct angiography to evaluate graft quality. As technology advances, more advanced machines are emerging in the market, and this journey continues to evolve. A study of symptomatic patients 10 ± 5 years after CABG surgery with 64-slice CT by Malagutti et al. showed that CTA was able to detect patency of graft with 100% sensitivity and 98.3% specificity taking ICA as a reference. They also concluded that overestimation of obstruction occurred in native coronary arteries especially when calcification was present . A meta-Magnetic resonance angiography (MRA) is another alternative for assessing the patency and quality of coronary bypass grafts. As invasive coronary angiography was associated with few minor complications, a noninvasive technique (MRA) that could assess the bypass graft was a major advancement in the field of medicine . As a noTransthoracic Doppler echocardiography (TDE) was first introduced by Gould in 1972 as a non-invasive tool for the assessment of venous grafts . TDE hasSince the 1990s, flow in the LIMA has been investigated using TDE ,87. SeveGiven the aforementioned studies, being a non-invasive, feasible, and versatile tool with a low risk of complications, TDE may be taken into consideration for the detection of IMA grafts. The ability of immediate, bedside, and late postoperative period assessment by TDE makes it a promising tool for assessments of IMA grafts, but highly skilled operators in performing and interpreting results are required.Taking ICA as a reference, the new intraoperative graft assessment modalities have their limitations. Even though they may help to identify failed grafts, the low sensitivity, specificity, PPV, and NPV, as shown in We always evaluate the performance of these newer noninvasive technologies in comparison with ICA, but the reliability of ICA, especially in the case of postoperative graft assessment, will only be proved with the development of a technology that is better than ICA. A study including 45 patients with 57 grafts by Hol et al. [Based on the intra- and postoperative noninvasive modalities result, as well as the result of ICA in this given study, it seems that there is still room for improvement in developing an easy-to-use, noninvasive graft assessment modalities that can provide both morphological and functional assessment of the graft, anastomosis, as well as the native coronaries, with no or minimum contrast and radiation. A high accuracy (specificity and sensitivity) would be the optimal goal of this technology so that a surgeon can easily rely on it.In the quest for assessing the quality of intra- and postoperative coronary artery bypass grafts, ICA remains the gold standard modality. Despite its undeniable strengths, the limitations of ICA sometimes render it unfeasible for use during or after surgery. Fortunately, research suggests that IFI/ICG angiography is another viable option for intraoperative graft assessment followed by TTFM, while CTA emerges as the most reliable option for postoperative graft evaluation after ICA. However, it is important to note that relying solely on these modalities may lead to overlooking failed grafts that require immediate revision or performing unnecessary revisions. Therefore, a surgeon’s clinical judgment remains a crucial factor in the decision-making process.