Long-term predictive value of stroke volume index obtained from right heart catheterization: Insights from the veterans affairs clinical assessment, reporting, and tracking program

Background: Right heart catheterization-derived hemodynamic parameters have been associated with short-term prognosis. Hypothesis: Hemodynamic parameters will be associated with long-term prognosis. Methods: Retrospective cohort study from the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program included patients who underwent an index right heart catheterization between 2008 and 2016. Cox proportional hazard models were used to examine the association between stroke volume index and all-cause mortality. Results: For the final cohort of 37 209 patients, mean follow-up was 3.7 ± 2.5 years. All-cause mortality was 42.0% in the low (<35 cc/beat/m²) compared with 33.2% in the normal stroke volume index group (≥35 cc/beat/m²). In adjusted analysis, low stroke volume was significantly associated with higher mortality risk (HR (95% CI) 1.14 (1.10-1.18); P <.001) independent of clinical parameters. The area under the curve (AUC) for continuous measures of stroke volume index at predicting mortality in a Cox proportional hazard model was 0.56 at 3 years. When stroke volume index was combined with 14 clinical covariates, the AUC was 0.70 at 3 years. The addition of stroke volume index to these clinical covariates did not increase the discriminatory ability of the model at 1 year in a clinically meaningful way (integrated discrimination improvement index = 0.0021, 95% CI: 0.0010-0.0034). Conclusions: The long-term prognostic value of right heart catheterization-derived stroke volume index appears to be marginal. While there was a weak association of low stroke volume index and excess mortality, inclusion of this parameter to a set of clinical covariates did not improve prognostic discrimination.