Controversial results of the Revised Cardiac Risk Index in elective open repair of abdominal aortic aneurysms: Retrospective analysis on a continuous series of 899 cases

Background: Low reliability of Revised Cardiac Risk Index (RCRI) in predicting major cardiac events (MACE) among Vascular Surgery patients emerged in recent literature, suggesting procedure-specific risk evaluation - particularly in major surgery. Methods-results: Comorbidities, perioperative variables, RCRI and MACE were retrospectively analyzed in a consecutive series of 899 elective open abdominal aortic aneurysm (AAA) repairs performed at our Institution. Possible MACE predictors were studied through univariate/multivariable analysis (logistic regression, MVRE) and stepwise-backward elimination/odds ratio (MVR-SBE/OR). Patients were divided by clampsite in 2 subgroups: 1. infrarenal (690 cases); 2. pararenal (209 cases). RCRI resulted predictive for MACE in the whole dataset but its performance resulted lower for pararenal aneurysms (p = 0.11) than for infrarenal ones (p ≤ 0.00). Among RCRI covariates of the whole cohort, dilated cardiomyopathy (p ≤ 0.001), ischemic cardiopathy (p ≤ 0.01) and cerebrovascular disease (p ≤ 0.02) resulted predictive. Peripheral arteriopathy also related to MACE (p ≤ 0.03). At MVR-SBE/OR analysis, the following resulted to be MACE predictors: dilated cardiomyopathy (p ≤ 0.001), cerebrovascular disease (p ≤ 0.02), and surgical access (p = 0.04) in subgroup 1; previous myocardial infarction (p ≤ 0.01), congestive failure (p ≤ 0.03) and chronic pneumopathy (p = 0.04) in subgroup 2. Conclusions: Predictability of RCRI in elective AAA surgery is influenced by clampsite and resulted to be lower in aneurysms requiring suprarenal clamping. Variables included in the RCRI show to have different weights when patients are stratified by clampsite. Some variables not included in the RCRI model significantly affect the onset of MACE. RCRI should be revised to elaborate a specific score for AAAs including further MACE predictors, to improve risk assessment and to support proper surgical strategy.