Lee, Sang Hoon

Background— The appropriate indication for coronary computed tomographic angiography (CTA) as a part of preoperative evaluation has not been defined yet. We investigated the value of coronary CTA in patients undergoing noncardiac surgery. Methods and Results— We included 844 patients (median age, 67 years; male sex, 62%) who underwent coronary CTA for screening of coronary artery disease before noncardiac surgery. Clinically determined revised cardiac risk index were compared with the extent and severity of coronary artery disease assessed by coronary CTA. Perioperative major cardiac event (PMCE), defined as cardiac death, myocardial infarction, or pulmonary edema within postoperative 30 days, developed in 25 patients (3.0%). Significant coronary CTA finding was defined as >3 any lesions with ≥1 (diameter stenosis ≥70%) stenosis based on the relationship between the severity of coronary artery disease and PMCE risk. The risk of PMCE was 14.0% in patients with significant CTA findings, whereas 2.2% of patients without significant CTA findings regardless of revised cardiac risk index score. The predictive performance of revised cardiac risk index could be improved significantly after addition of significant coronary CTA findings (c-statistics=0.631 versus 0.757; net reclassification improvement=0.923; integrated discrimination improvement=0.051). On the basis of revised cardiac risk index and coronary CTA, the risk of PMCE could be estimated with sensitivity, specificity, positive predictive value, and negative predictive value of 76%, 73%, 8%, and 99%, respectively. Conclusions— Addition of coronary CTA to clinical risk improved perioperative risk stratification. Absence of significant coronary CTA findings conferred low PMCE risk with high specificity and negative predictive value regardless of clinical risk. Coronary CTA may improve perioperative risk stratification in patients undergoing noncardiac surgery.

Background— Coronary collateral flow is an alternative source of myocardial perfusion in patients with totally occluded coronary arteries. Clinical evaluation of collateral flow has been limited by the need of invasive measurements. We investigated whether noninvasive coronary computed tomographic angiography can evaluate the angiographic extent of coronary collateral flow. Methods and Results— We enrolled 325 coronary computed tomographic angiography cases with angiographically confirmed chronic total occlusion (median age, 63 years; men 83%). Transluminal attenuation gradient (TAG), which reflects the kinetics of contrast media in coronary artery, of an entire artery as well as of a distal vessel was assessed to evaluate the flow in entire vessel and distal vessel. TAGs were validated against visually assessed angiographic collateral connection and Rentrop grading. TAG of an entire artery increased consistently according to the angiographic extent of collateral flow ( P <0.001). Well-developed collaterals, defined by highest collateral connection and Rentrop grades (n=103), could be predicted by TAG of an entire artery (cutoff, ≥−7.6 Hounsfield units/10 mm; c -statistics, 0.72; sensitivity, 65%; specificity, 73%; positive predictive value, 52%; negative predictive value, 82%). TAG of a distal vessel could discriminate the antegrade (n=143) and retrograde (n=182) flows in distal artery (cutoff, 0.0 Hounsfield unit/10 mm; c -statistics, 0.88; sensitivity, 78%; specificity, 85%; positive predictive value, 87%; negative predictive value, 75%). Conclusions— TAG, an intracoronary attenuation-based analysis of coronary computed tomographic angiography, moderately reflected the functional extent and direction of collateral flow.