Clinical Risk Model of 30-Day Mortality After TAVR Developed With Functional Status Measures
March 20, 2018—Investigators from the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry developed a clinical risk model for 30-day mortality after transcatheter aortic valve replacement (TAVR) that includes clinical data as well as health status and frailty. The model will facilitate tracking outcomes over time as TAVR expands to lower-risk patients and to less-experienced sites and will allow an objective comparison of short-term mortality rates across centers, concluded the investigators. The study of the development and validation of the model was published by Suzanne V. Arnold, MD, et al in Journal of the American College of Cardiology (JACC): Cardiovascular Interventions (2018;11:581–589).
According to the investigators, the background of this study is that risk assessment for TAVR is important both for patient selection and provider comparisons. Previous efforts for risk adjustment have focused on in-hospital mortality, which is easily obtainable but can be biased because of early discharge of ill patients.
As summarized in JACC: Cardiovascular Interventions, the investigators used data from patients who underwent TAVR as part of the STS/ACC TVT Registry from June 2013 to May 2016. They developed and internally validated a hierarchical logistic regression model to estimate the risk for 30-day mortality after TAVR based only on preprocedural factors and access site used.
The model includes factors from the original TVT Registry in-hospital mortality model but added the Kansas City Cardiomyopathy Questionnaire (health status) and gait speed (5-m walk test).
The investigators reported that among 21,661 TAVR patients at 188 sites, 1,025 patients (4.7%) died within 30 days. Independent predictors of 30-day mortality included older age, low body weight, poor renal function, peripheral artery disease, home oxygen use, previous myocardial infarction, left main coronary artery disease, tricuspid regurgitation, nonfemoral access, poor baseline health status, and inability to walk. The predicted 30-day mortality risk ranged from 1.1% (lowest decile of risk) to 13.8% (highest decile of risk).
The model was able to stratify risk on the basis of patient factors with good discrimination (C = 0.71 [derivation]; C = 0.70 [split-sample validation]) and excellent calibration, both overall and in key patient subgroups, report the investigators in JACC: Cardiovascular Interventions.