Prognostic Value of Shock Index Creatinine in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Replacement

Abstract

Introduction: Shock index (SI) and its derivatives have been reported to have prognostic value in various cardiovascular diseases. This study aims to ascertain the utility of shock index creatinine (SIC) in predicting mid-term mortality among patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). Methods: We conducted a retrospective analysis of 555 patients with severe AS who underwent TAVR from April 2016 to March 2023. SIC was calculated as (SI × 100) - estimated creatinine clearance (CCr). The primary endpoint was all-cause mortality during the follow-up period, and secondary endpoints included in-hospital complications as defined by the Valve Academic Research Consortium-3 (VARC-3) criteria. Patients were stratified into two groups based on the optimal cut-off value determined by the receiver operating characteristic (ROC) curve. Cox regression analysis was employed to identify independent predictors of all-cause mortality. Additionally, restricted cubic spline (RCS) was deployed to illustrate the relationship between SIC and mortality risk. The predictive performance of risk scores was evaluated using the area under the ROC curve (AUC). Results: Over a mean follow-up period of 21.5 months, there were 51 cases of all-cause mortality. Patients with a high SIC, identified by a cut-off of 16.5, exhibited a significantly higher cumulative all-cause mortality compared to those with a low SIC (18.3% vs. 5.2%, p < 0.001; adjusted HR=2.188; 95% CI 1.103-4.341, p = 0.025). Patients with a high SIC were older (p = 0.002) and exhibited a higher prevalence of frailty (p<0.001). Furthermore, they exhibited a heightened probability of moderate or severe mitral regurgitation (p < 0.001), tricuspid regurgitation (p < 0.001), and pulmonary hypertension (p < 0.001) compared to those with a low SIC. In terms of perioperative complications, acute kidney injury (10.1% vs. 3.9%, p = 0.008) and bleeding (13.6% vs. 6.7%, p = 0.014) were more prevalent in patients with a high SIC. The RCS demonstrated a positive correlation between SIC and all-cause mortality rate. Furthermore, incorporating high SIC into the STS score improved its predictive value for 1-year all-cause mortality (AUC: 0.731 vs. 0.649, p=0.01). Conclusion: Patients with a high SIC are more likely to experience frailty and cardiac damage and exhibit an increased in-hospital and mid-term mortality rate. SIC may provide additional information for risk stratification of patients undergoing TAVR.