Study to assess the applicability of EuroSCORE II and STS score in Indian cardiac patients undergoing valve surgeries

Valvular heart disease (VHD) encompasses various structural cardiac abnormalities that disrupt normal blood flow during the cardiac cycle. In low and middle socioeconomic countries like India, rheumatic heart disease (RHD) remains a significant cause of VHD-related mortality and disability, despite a decline in global numbers. Degenerative valve disease, on the other hand, has become the most prevalent form of VHD in developed countries due to the aging population. With over one million cardiac valve surgeries performed worldwide annually, the need for objective risk scoring systems for patients undergoing these surgeries has become crucial.

Accurate risk stratification of patients undergoing cardiac valve surgeries is essential for multiple purposes, including comparing institutional practices, improving treatment decision-making, cost-benefit analysis, patient counselling, and quality improvement. The 2 models currently used worldwide for cardiac surgical patients are – Society for Thoracic Surgery (STS) and the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II). The STS risk score, which undergoes periodic updates, has proven highly effective for predicting mortality risk in cardiac surgical patients in the west and offers models for coronary artery bypass graft (CABG), isolated valve surgery, and valve surgery plus CABG. The EuroSCORE II is the recommended risk assessment model for cardiac surgeries globally. It predicts the probability of in-hospital mortality and was accepted for clinical use in 2011.

While institutions in India rely on either EuroSCORE II or the STS score for risk stratification, there is a lack of large-scale studies validating the applicability of these scoring systems in the Indian population, which typically presents with long standing disease, poor nutritional status and multiple associated comorbidities. Some studies have shown conflicting results regarding the accuracy of EuroSCORE II in predicting mortality in Indian patients, suggesting both under-prediction and over-prediction however limited data exists for the validation of the STS as well as EuroSCORE II in the Indian population.

In light of the challenges faced by tertiary cardiac centres in India, which cater to a growing number of patients with valvular heart diseases, the present study proposes a prospective observational analysis of valve surgery patients at a specific centre. The study will be conducted over a period of 1 year including a sample size of 200 patients undergoing cardiac valvular surgeries. Preoperative STS score will be calculated using https://riskcalc.sts.org/stswebriskcalc/calculate and EuroSCOREII will be calculated using calculator available on https://www.euroscore.org/index.php?Id=17. Other observations will be patient BMI, duration since first presenting symptom in the patient, aortic cross clamp time and total CPB time, VIS score for inotropic support after surgery, number of days for postoperative mechanical ventilation, need for reexploration, days to discharge from ICU and whether the patient had death or discharge from hospital.