Noninvasive coronary angiography: agreement of multi-slice spiral computed tomography and selective catheter angiography

Background: Technology advances in multislice detector computed tomography (MSCT) cardiac scanning, specifically in the application of intravenous injected contrast coronary angiography with EKG gating have led to the availability of this procedure in every day outpatient cardiac medicine. Objective: The aim of this study is to test the head to head direct coronary angiography with MSCT coronary angiography in clinical situations where cardiac cath is traditionally utilized for management decisions. Methods: We limited our analysis to vessels felt to be 1.5 mm or greater in diameter, recognizing diagnostic accuracy and medical importance of smaller vessels is low. All 50 patients (52% men, 48% women age range 34-78) were studied because of the clinical suspicion of obstructive coronary atherosclerosis. Blinded experts in direct and in MSCT independently read the studies and resolved disparities by a subsequent discussion. Standard protocols for direct and for MSCT angiography were used including use of IV and oral beta blockade to keep the heart rate at or below 60 beats per minute. Results: 392 vessels were evaluated. MSCT provided images of sufficient technical quality to permit diagnosis in 98% (49/50) of cases. MSCT was 96% accurate in identifying patients as having either no disease, single vessel disease, or multiple vessel disease. For all vessels, MSCT identification of stenotic lesions of > 50% were as follows: sensitivity 87%, specificity 97%, positive predictive value 80%, and negative predictive value 98%. Pearson correlation results between direct catheter and MSCT for absolute stenotic percentages were left main (0.92 p < 0.0001), left anterior descending (0.94 p < 0.0001), circumflex (0.94 p < 0.0001), first obtuse marginal (0.85 p < 0.0001), and right coronary artery (0.89 p < 0.0001). Conclusion: The accuracy of MSCT angiography compared favorably with that of direct cardiac cath in this cohort of patients. The high specificity of these findings suggest that one particular use of this technique will be to eliminate many unnecessary cardiac catheterization procedures by excluding obstructive, and therefore potentially PCI requiring, coronary artery disease. The medical cost savings of such an application may be very significant and bears further study.