Abstract 14475: Echocardiographic Predictors of Long Term Survival in Patients Undergoing Cardiac Resynchronization Therapy: What is the Optimal Metric?
Background: The reverse ventricular remodeling (RVR) effects of cardiac resynchronization therapy (CRT) are used as descriptors of treatment effect and surrogates for outcomes. Multiple definitions of RVR employing various changes in left ventricular end-systolic (LVESV) or diastolic volumes (LVEDV) (with or without an index to body surface area) or left ventricular ejection fraction(LVEF) have been tied to differing patient outcomes making comparisons among CRT studies difficult. Here, we compared these different metrics to each other, and in combination, with respect to predicting long term outcomes following CRT.
Methods: We collected clinical and echocardiographic data on 436 patients with advanced heart failure undergoing CRT. LV volumes were traced in the apical 4 chamber view. LVEF was determined via a combination of volumetric analysis and visual assessment. The following definitions of RVR were created: any improvement in LVEF, improvement in LVEF ≥5% and ≥10% and reductions in LVESV and LVEDV (any), ≥5%, ≥10%, ≥15%, and ≥20%, and combinations of both LVESV reduction and LVEF. Using a nested multivariate model of a priori determined predictors of long term survival free of LVAD or heart transplant, each definition was added to the model individually to determine which provided the best model fit for prediction of long term outcomes.
Results: Over a mean follow up of 5.4±2.3 years, there were 198 endpoints (10 LVADs, 15 heart transplants, and 173 deaths). When added to a nested model controlling for gender, cardiomyopathy subtype, ICD (CRTD vs. CRTP), LBBB, paced QRS complex, QRS duration, beta blocker use, ACE inhibitor use, creatinine, hemoglobin, and pre-CRT LVEF, all definitions of RVR were significantly associated with improved survival. Changes in LVEF and LVESV were superior to changes in LVEDV. A combination metric of an LVEF improvement≥5% and LVESV reduction≥10% was the best overall metric for model fit.
Conclusions: Although reductions in LVESV, LVEDV, and improvement in LVEF are all associated with improved long term outcomes following CRT, changes in LVEF and LVESV were superior to changes in LVEDV. The combination of both improvement in LVEF ≥5% and reduction in LVESV ≥10% was the best predictor of long term outcomes.
Author Disclosures: J. Rickard: Consultant/Advisory Board; Modest; Medtronic. R. Grimm: None. Z. Popovich: None. P. Collier: None. B. Baranowski: None. W. Tang: Research Grant; Significant; National Institutes of Health. M. Niebauer: None. B. Wilkoff: Honoraria; Modest; Medtronic, Boston Scientific, St. Jude, Spectranetics, Convatec. N. Varma: Consultant/Advisory Board; Modest; Biotronik, Medtronic, Sorin Group, St. Jude Medical.
- © 2016 by American Heart Association, Inc.