High‐risk coronary anatomy versus high‐risk physiology as outcome predictors in acute coronary syndromes

Current practice guidelines recommend an early invasive strategy for intermediate to high-risk non-ST elevation acute coronary syndrome (NSTE-ACS) patients. Given the increasing incidence of NSTE-ACS over the past decade and the substantial associated morbidities, the use of risk prediction scores has become essential in the identification of patients most likely to benefit from an invasive approach. The Global Registry of Acute Coronary Events (GRACE), Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin (PURSUIT) and Thrombolysis In Myocardial Infarction (TIMI) scores are well-validated models that integrate multiple clinical variables to predict outcomes in this population [1]. In contrast, the Synergy Between PCI With Taxus and Cardiac Surgery (SYNTAX) score is an anatomical-based model similar to the ACC/AHA Classification System for angiographic prediction of outcome and is designed to help in deciding the optimal strategy of revascularization in complex coronary artery disease (CAD) [2]. The Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial, subgroup of NSTE-ACS patients treated with urgent percutaneous revascularization, showed that the SYNTAX score was an independent predictor of 1-year mortality, cardiac death, acute MI, and target vessel revascularization on multivariate analysis. Furthermore, the Clinical SYNTAX score [3], achieved by combining the SYNTAX Score with a modified age, creatinine, and ejection fraction (ACEF) score has been shown to perform better than purely clinical scores in predicting cardiac death, major adverse cardiac and cerebrovascular events (MACCE), stent thrombosis, MI, and target vessel revascularization in the ACUITY trial [4]. Although the utility of these various models in risk assessment is well proven, they are not designed to predict the severity of CAD, a variable that intuitively can be meaningfully associated with outcomes. In this issue of Catheterization and Cardiovascular Interventions, Beigel et al. [5] point out that current risk scores for NSTE-ACS may fail to identify some patients with severe CAD. The study aims at identifying predictors of high-risk coronary anatomy (HRCA)—defined as left main disease >50% diameter stenosis, proximal left anterior descending (LAD) lesion >70%; or 2–3 vessel disease involving the LAD—and evaluating their impact on prognosis. This retrospective study based on the nationwide registry Acute Coronary Syndrome Israeli Survey included 923 patients with NSTE-ACS who underwent coronary arteriography. Multivariable analysis revealed that the presence of peripheral vascular disease, GRACE score> 140, and chronic renal disease were the strongest predictors of HRCA. Among 370 patients found to have HRCA, 85 patients (23%) did not meet criteria for an early invasive strategy solely using GRACE score> 140, ST-segment depressions on electrocardiography, positive cardiac biomarkers, or Killip Class 2 on admission. The prognostic implications of these findings are important as patients with HRCA had more in-hospital complications such as cardiogenic shock and pulmonary edema and higher frequency of moderate to severe mitral regurgitation, need for surgical revascularization, MACCE at 30 days, and mortality at 30 days and at 1 year. Based on multivariate analysis, HRCA was the strongest predictor of MACCE at 30 days. This study raises the issue that relying solely on individual risk stratification scores may fail to identify some patients with severe CAD who would benefit from an early invasive strategy. It makes sense that the “extent of disease” can be distinct from “acuity of disease” with each having important clinical implications. A few thoughtprovoking questions arise from this study. Should we routinely assess HRCA scores in NSTE-ACS patients? Is it essential to identify patients early with low-risk clinical scores but high-risk HRCA scores to improve outcomes, or