Volume-outcome relationships for transcatheter aortic valve replacement-risk-adjusted and volume stratified analysis of TAVR outcomes

Abstract

ObjectivesThis purpose of the study was to evaluate TAVR outcomes at low, intermediate and high volume institutions. BackgroundFor the care of complex patients, volume-outcome effect is well described. The initial US TAVR experience was limited to a few centers of excellence. The impact of institutional volume on outcomes after TAVR has not been systematically studied. MethodsWithin the Banner Health system, TAVR is performed at 3 institutions-a low volume, an intermediate volume and a high volume institution. 181 consecutive patients undergoing TAVR within these 3 institutions were the study cohort. To adjust for bias and confounders between the 3 groups, risk-adjusted multivariate logistic regression and propensity score analysis was performed. The primary endpoint was a composite of mortality, dialysis-dependent renal failure, cerebrovascular accident, need for new permanent pacemaker and readmission within 30days. ResultsThe primary endpoint was reached in 38.8% of patients at the high volume institution and 76.2% of patients at the low volume institution (p<0.01). Having a TAVR procedure at a larger volume institution was an independent predictor of having improved outcomes (OR 0.33, 95% CI 0.16–0.68; p=0.003). These improved outcomes after the TAVR procedure noted at the large volume institution were seen in the most complex patients: age ≥80years, BMI >30, diabetes, hypertension, prior CAD, CKD and NYHA class III/IV heart failure. ConclusionsHigh-risk patients undergoing TAVR at a large volume institution have better 30-day outcomes compared to outcomes at intermediate and low volume centers.