Abstract 16005: OptiVol® Impedance Threshold Crossing Predicts Higher Mortality and Hospitalization Risk Among Medicare Recipients
Introduction: The long-term prognostic value of Optivol® measurements on clinical events and mortality in a real-world cohort of cardiac resynchronization therapy defibrillator (CRT-D) patients with Medicare coverage is unknown.
Hypothesis: We hypothesized that OptiVol® threshold crossings would be associated with increased adjusted risk of patient mortality and heart failure-related hospitalizations in Medicare patients.
Methods: A cohort combining the Medicare Implantable Cardioverter-Defibrillator Registry data (implanted in 2005 and 2006), Medicare claims data, and data from Medtronic’s CareLink® Network were analyzed via an extended Cox model to assess the associations of impedance threshold crossings (OptiVol®) with both patient mortality and heart failure-related hospitalization. OptiVol® crossings were treated as time-dependent covariates.
Results: N= 1,565 patients with OptiVol®-enabled CRT devices were included in this analysis. The median follow-up was 6.3 years. An OptiVol® crossing at any point in the follow-up period was associated with a 91% increased rate of patient death (HR 1.91, 95% CI: 1.30-2.82) after adjustment for ischemic heart disease, gender, smoking status, age at implant, systolic blood pressure, diabetes status, previous SCA event, and the prescription of digoxin, ACE inhibitors, and angiotensin receptor blockers. Furthermore, after adjusting for these same covariates, an OptiVol® crossing at any point was associated with an 74% increased rate of a heart failure related hospitalization (HR 1.74, 95%CI: 1.31-2.32).
Conclusion: In a Medicare cohort of CRT patients, OptiVol® crossings were associated with increased rates of mortality and hospitalization, which has important implications for clinical care. This is the first study integrating device-measured data with Medicare outcomes data to validate the long-term significance of thoracic impedance measurements in this population.
Author Disclosures: J.R. Brown: Employment; Significant; Medtronic PLC. K.C. Bilchick: None. A. Alonso: None. E.N. Warman: Employment; Significant; Medtronic PLC.
- © 2016 by American Heart Association, Inc.