Evaluation of Risk Indices in Continuous-Flow Left Ventricular Assist Device Patients

Background. The Leitz-Miller (LM), Columbia (COL), Acute Physiology and Chronic Health Evaluation II (APACHE II), Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS), and Seattle Heart Failure Model (SHFM) risk scores have been used to risk stratify patients with pulsatile-flow left ventricular assist devices (LVAD). We assessed the predictive ability of these scores in a cohort of continuous-flow LVAD patients. Methods. Preoperative scores were calculated from prospective data of patients who received continuous-flow LVADs between June 2000 and May 2009. Cox proportional hazard analysis assessed the effect of pre-operative variables and scores on 30-day, 90-day, and 1-year mortality. Patients were stratified by score into low-and high-risk groups. Survival was modeled using the Kaplan-Meier method. Results. During the study period, 86 continuous-flow LVADs were implanted. The mean (+/- standard deviation) preoperative scores were: COL, 1.05 +/- 1.59; LM, 11.9 +/- 5.4; APACHE II, 15.6 +/- 4.3; INTERMACS, 2.64 +/- 1.01; and SHFM, 2.97 +/- 1.42. On univariate analysis, the SHFM score best differentiated low-and high-risk patients at all mortality end points; the INTERMACS and APACHE II scores were predictive for 90-day and 1-year mortality. On multivariable analysis, SHFM (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.02 to 2.21; p = 0.04) and APACHE II (HR, 1.10; 95% CI, 1.01 to 1.21; p = 0.04) predicted 1-year mortality. Conclusions. Among the LM, COL, APACHE II, INTERMACS, and SHFM scores, the best predictor of mortality in a single institutional cohort of continuous-flow LVAD patients was the SHFM score.