Development of cardiac risk assessment model for vascular surgery patients based on single-center experience

Abstract

Introduction: Existing methodologies and risk stratification indices from western countries for predicting perioperative cardiac complications in vascular surgery patient lack sufficient predictive value and therefore cannot be recommended for risk stratification. There are no Indian studies for preoperative cardiac risk scores for patients who undergo vascular and endovascular procedures. The aim of this study is: (a) to test the usefulness of Detsky's cardiac index in an independent series of patients who underwent peripheral arterial vascular procedures and (b) to develop cardiac risk assessment model. Materials and Methods: We studied 103 patients at single-center who underwent cardiac risk stratification before undergoing vascular interventions. It was a prospective cohort study for 2 years. The Detsky's cardiac risk index was calculated for each patient to predict perioperative cardiac risk in patients undergoing vascular interventions. Sensitivity, specificity, positive and negative predictive values were calculated. To determine the accuracy of stratification for Detsky's index, the area under the receiver-operating characteristic curves was also calculated. Results: Eighteen patients (17.4%) had cardiac complications. The Detsky's index was found to be a satisfactory predictor of postoperative cardiac events (P < 0.001). There were a total of 10 mortalities (9.7%) with the Detsky's model, having positive predictive value of 73.3% and specificity of 94.1%. Discussion: The overall sensitivity, specificity, positive predictive value, negative predictive value of the Detsky's risk index in the prediction of cardiac events was 31.4%, 94.1%, 73.3%, 72.7% respectively. In our study, the area under ROC for Detsky class was 0.76 versus 0.75 and superior to C statistic. One important inference from the study was that 77.6% patients were smoker in the study group which emphasize direct relation of peripheral vascular disease with smoking. Conclusion: The study concluded that patients with good surgical risk and profile undergoing minor vascular procedures can be operated without further testing. For other patients, the next step would be to incorporate the Detsky index. A Detsky score of 20 or more is comparable to a major clinical predictor in the ACC/AHA15 scheme.