Novel CV risk index improves stratification of patients scheduled for noncardiac surgery
A study has recently derived and validated a new index for preoperative cardiovascular evaluation, which can significantly contribute to the efficient triage and management of patients scheduled for noncardiac surgery. The new Cardiovascular Risk Index (CVRI) demonstrates a robust discriminatory power that can effectively stratify patients into low-, intermediate- and high-risk groups.
This study included a derivation cohort consisting of 3,284 prospectively enrolled adult patients undergoing noncardiac surgery at the American University of Beirut Medical Center and a validation cohort consisting of 1,167,414 patients registered in the American College of Surgeons National Surgical Quality Improvement Program database.
The primary outcome of death, myocardial infarction or stroke at 30 days after surgery occurred in 38 patients (1.2 percent) in the derivation cohort.
Six data elements to be included in the prediction model were identified in this cohort via multivariate logistic regression analysis: age ≥75 years, history of heart disease, symptoms of angina or dyspnoea, hemoglobin <12 mg/dl, vascular surgery, and emergency surgery. Each patient was assigned a CRVI of 0, 1, 2, 3 and >3 based on the number of data elements present.
Primary outcome incidence rose steadily across the CVRI groups in both the derivation (0 percent, 0.5 percent, 2.0 percent, 5.6 percent and 15.7 percent, respectively; p<0.0001) and validation (0.3 percent, 1.6 percent, 5.6 percent, 11.0 percent and 17.5 percent, respectively; p<0.0001) cohorts.
A receiver-operating characteristic curve, with respective areas under the curve of 0.90 and 0.82 in the derivation and validation cohorts, confirmed the discriminatory power of the new CVRI.
“Currently used indices for preoperative cardiovascular evaluation are either powerful, but complex, or simple, but with weak discriminatory power,” the authors said.