"Results of a headtohead comparison study led by Johns Hopkins researchers show that noninvasive CT scans of the hearts vessels are far better at spotting clogged arteries that can trigger a heart attack http_healthheart_attack_P than the commonly prescribed exercise stress that most patients with chest pain undergo. A report on the findings comparing CT angiograms http_procedurescardiovascularcomputed_tomography_angiography_cta_ and stress tests http_diseaseselectrocardiogram_ekg_stress_test_holter_monitor_P published online Oct.  in the journal Circulation Cardiovascular Imaging httpcircimaging.ahajournals.orgcontente.fullsidacecbbcadae show the scans correctly identified blockages in nine out of  people while stress tests picked up blockages in six out of . What renders the results of the new study particularly powerful researchers say is that each patient underwent all three tests for providing a direct headtohead comparison of their ability to accurately spot blockages. No tests is  percent accurate  percent of the time but our findings indicate CT angiograms get pretty close to that coveted threshold says lead investigator Armin Zadeh M.D. Ph.D. http associate professor of medicine at the Johns Hopkins University School of Medicine. We hope our findings will settle any residual uncertainty about the effectiveness of these two common noninvasive heart tests. The researchers note that the gold standard for detecting blocked arteries remains invasive cardiac angiography a test using dye and Xrays http_P that requires a catheter to be threaded into the hearts vessels. But cardiologists have long relied on socalled stress testing as a simpler cheaper gatekeeper procedure to identify people more likely to benefit from the riskier more invasive and more costly catheterizations. CT angiograms have recently emerged as yet another noninvasive alternative. A handful of studies Zadeh says have suggested CT angiographies may be superior but uncertainty has persisted due the small number of people involved in these analyses and stress tests have remained the more popular choice among clinicians. Results of the new study the research team says should help settle lingering doubts among physicians and the nearly  million Americans who seek medical attention each year for symptoms that signal a clogged artery including chest pain shortness of breath and extreme fatigue. In CT angiography clinicians use dye injected into the circulation to visualize blockages inside the arteries. When the dye reaches impenetrable or narrowed passages clogged by fatty buildups or clots the scan shows a blockage. The socalled nuclear exercise stress tests also use dye and CT scans but instead of directly visualizing the interior of the arteries they measure blood flow to the heart muscle immediately after a patient walks on a treadmill. Reduced blood flow to the heart muscle is a signal that a narrowed or blocked artery is not supplying the muscle with enough blood. Although exercise stress testing is generally safe for most people it can rarely trigger an abnormal heart rhythm or even an actual heart attack in people with seriously clogged arteries. Researchers emphasize that both nuclear stress tests and CT angiograms expose patients to radiation. While many newer CT scans deliver substantially lower doses of radiation than the scans used in nuclear stress tests the dose and protocols can vary widely from hospital to hospital researchers say. CT angiograms and nuclear stress tests carry similar price tags between  and . Researchers say the total tab stemming from either test including downstream costs related to additional testing due to unclear or unrelated findings remains unclear and should be an important consideration in crafting any new testing recommendations. For the current study  patients ages  to  seen at  hospitals in eight countries underwent noninvasive CT angiograms followed by traditional catheterbased coronary angiographies. Within two months each patient also underwent an exercise stress test. All patients had symptoms suggestive of heart disease http_diseasescoronary_heart_disease_P but not all had a previous diagnosis of the condition. Overall noninvasive CT angiograms accurately detected or ruled out artery blockages in  percent of patients compared with  percent for stress testing. When researchers analyzed test performance in a subgroup of  patients with very highrisk disease as identified on traditional angiography the diagnostic accuracy of CT angiograms went up to  percent compared with  percent for stress testing. In other words researchers report stress tests missed two out of every  patients with severe disease marked by multiple blockages. Current guidelines from the American Heart Association and the American College Cardiology call for a stress tests in all patients who show signs of coronary artery disease to confirm the diagnosis and define the severity of the blockage. CT angiograms are generally reserved only for patients with borderline stress test results. But given its much higher accuracy the researchers say CT angiography may be a better firstline test in people with symptoms suggestive of a blocked artery. Other investigators from Johns Hopkins included Rodrigo Cerci Richard George Andrea Vavere Joo Lima Jeffrey Brinker https and Julie Miller. Other institutions involved in the research included Brigham and Womens Hospital Charit Hospital in Germany St. Lukes Hospital in Japan Beth Israel Deaconess Medical Center and the University of Sao Paulo in Brazil. The work was funded by the National Heart Lung and Blood Institute under grant number HL and by Toshiba Medical Systems manufacturer of the scanner used in the trials. Relevant disclosures Lima has received grant support from Toshiba Medical Systems."