Gwon, Hyeon‐Cheol

Background: About 25% of patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS) have chronic total occlusion (CTO) at non-culprit artery. However, the prognostic impact of CTO in these patients is still unclear. Aims: We aimed to investigate the impact of CTO at non-culprit artery on 1-year mortality in patients with AMI-CS using the multicenter registry of cardiogenic shock. Methods: A total of 1,247 patients presented with cardiogenic shock (CS) were enrolled in the SMART-RESCUE registry between January 2014 and December 2018. After exclusion of non-ischemic cause shock, ischemic cardiomyopathy, failed or no revascularization, vasospasm, and patients undergoing coronary artery bypass surgery, 695 patients underwent percutaneous coronary intervention (PCI). Among these, we analyzed 536 patients with multivessel disease (MVD) according to the presence of CTO at non-culprit artery. The study endpoint was a 1-year all-cause mortality. We also examined the incidence of 1-year cardiac death, and in-hospital death or renal replacement therapy (RRT). Results: A 141 patients (26.3%) of study population had CTO lesion at non-culprit artery. The CTO group had more patients with diabetes mellitus, and lesser patients with ST-elevation myocardial infarction. Although initial left ventricular ejection fraction was lower in CTO group (28.5 vs. 34.1%, P=0.005), initial systolic blood pressure (73.8 vs. 73.2 mmHg, P=0.822) and the level of lactate (6.6 vs. 6.4 mmol/L, P=0.804) were similar in both groups. Venoarterial extracorporeal membrane oxygenation was applied in 206 patients (38.4%), and its use rate was comparable in 2 groups (40.4 vs. 37.7%, P=0.571). Pre- (32.9 vs. 22.9, P <0.001) and post-PCI SYNTAX score (16.7 vs. 5.3, P <0.001) was significantly higher in CTO group. In CTO group, 53 patients (37.6%) had CTO at left main or left anterior descending artery, and only 19 patients (13.5%) in CTO group received PCI for CTO. In multivariate analysis, all-cause mortality at 1-year was significantly higher in CTO group (51.8 vs. 40.5%, hazard ratio [HR] 1.44, 95% confidence interval [CI] 1.09-1.90, P=0.011). The incidences of 1-year cardiac death (45.4 vs. 32.4%, HR 1.55, 95% CI 1.15-2.10, P=0.004) and in-hospital death or RRT (46.8 vs. 36.5%, P=0.031) were also higher in CTO group. Conclusions: Non-culprit CTO lesion was associated with higher 1-year mortality in patients with AMI-CS and multivessel disease.

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.

Background— Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction is often challenging. Using cardiac MRI, we investigated the frequency and extent of myocardial infarction in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow. Methods and Results— We included 170 consecutive patients (median age, 62 years) with angiographically documented CTO. Regional late gadolinium enhancement and wall motion score index were assessed by cardiac MRI with the use of a 17-segment model. Angiographic collateral flow was assessed by the collateral connection grade and the Rentrop score. Evidence of previous myocardial infarction was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by late gadolinium enhancement. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, and a lower regional wall motion score index, late gadolinium enhancement volume (%), and degree of late gadolinium enhancement transmurality (all P <0.001), as well. Conclusions— The frequency of myocardial infarction in territories subtended by CTO is significantly higher than previously recognized. The degree of myocardial injury downstream epicardial CTO is inversely correlated with the degree of angiographic collaterals.