The Heartmate Risk Score predicts morbidity and mortality in unselected left ventricular assist device recipients and risk stratifies INTERMACS class 1 patients

Abstract

Objectives: This study evaluated the Heartmate Risk Score (HMRS) and its potential benefits in clinical practice.

Background: The HMRS has been shown to correlate with mortality in the cohort of patients enrolled in the Heartmate II trials, but its validity in unselected, "real world" populations remains unclear.

Methods: This study identified a cohort of 269 consecutive patients who received a Heartmate II left ventricular assist device at our institution, the Barnes-Jewish Hospital in St. Louis, Missouri, between June 2005 and June 2013. Ninety-day and 2-year mortality rates, as well as frequency of several morbid events, were compared by retrospectively assigned HMRS category groups. The analysis was repeated within the subgroup of INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) class 1 patients.

Results: Receiver operating curve analysis showed that the HMRS correlated with 90-day mortality with an area under the curve of 0.70. Stratification in low, mid, and high HMRS groups identified patients with increasing hazard of 90-day mortality, increasing long-term mortality, increasing rate of gastrointestinal bleeding events, and increasing median number of days spent in the hospital in the first year post implant. Within INTERMACS class 1 patients, those in the highest HMRS group were found to have a relative risk of 90-day mortality 5.7 times higher than those in the lowest HMRS group (39.1% vs. 6.9%, p = 0.029).

Conclusions: HMRS is a valid clinical tool to stratify risk of morbidity and mortality after implant of Heartmate II devices in unselected patients and can be used to predict short-term mortality risk in INTERMACS class 1 patients.

Keywords: heart failure; left ventricular assist device; survival; transplantation.