Abstract 19140: Prediction of Inotrope Initiation in Patients With Advanced Heart Failure

Abstract

Introduction: It is now widely accepted that the need for inotropic therapy initiation in advanced heart failure (INTERMACS Class 3) in otherwise suitable patients constitutes the closing point of the ideal time window to initiate long term mechanical circulatory support. In this study, we sought to predict this time point. Hypothesis: Maximal exercise testing in conjunction with echocardiographic parameters can be used to objectively stratify a pts risk for inotrope dependence. Methods: We conducted a prospective study of pts in various stages of HF. Cardiopulmonary exercise testing and echocardiograms were performed at baseline, and the pts were followed for 48 months. The primary endpoint was inotrope initiation; secondary endpoints included LVAD implantation, heart transplantation, and death. Results: One hundred and thirty-five pts were enrolled. The mean pt age was 53 ± 13 years, 74% were male, and 34% had ischemic cardiomyopathy. The cohort was 15%, 40%, 45%, and NYHA Class I, II, and III respectively. Pts were followed for a median duration of 31 months (IQR: 16-46). Since enrollment, 19 pts (14.1%) have been initiated on inotrope therapy. Univariate predictors of inotrope dependence that were entered into the multivariable Cox model are: left ventricular ejection fraction, peak oxygen consumption, and heart rate reserve >45%. The derived score predicts inotrope initiation within one year with a sensitivity of 78.6% and specificity of 73.7% (ROC curve AUC=0.82). Probability of inotrope initiation was well stratified by scoring quartiles. Conclusion: A simple score comprised of left ventricular ejection fraction, peak oxygen consumption, and heart rate reserve >45% can help predict HF deterioration. Validation of a successful model which predicts time to inotrope use would be beneficial for appropriate timing of mechanical circulatory support.