Continuing cardiac resynchronization therapy (CRT) appeared to offer no benefit to patients who received a continuous flow left ventricular assist device (CF-LVAD), according to a multicenter study published in the Journal of the American Heart Association.
Rakesh Gopinathannair, MD, with the University of Louisville, and colleagues studied 488 patients with either an implantable cardioverter defibrillator (ICD) or a CRT device (CRT-D) who received CF-LVADs. After multivariable adjustment, they found no difference in survival or rates of ventricular arrhythmia between groups. However, more CRT-D patients (26 percent) required pulse generators compared to the ICD group (15.5 percent).
“Based on our results, it appears reasonable to turn off the (left ventricular) lead in CRT‐D patients following CF‐LVAD implant to save battery life and limit frequent pulse generator replacements,” the researchers wrote. “This is especially important given the higher risk of infection and periprocedural bleeding associated with procedures in the CF‐LVAD population.”
Mean follow-up for both groups was 620 days. Twenty-nine percent of patients died in the CRT-D group compared to 25 percent of patients in the ICD group, and a similar number of patients in each group underwent heart transplantation.
“There was a strong but nonsignificant trend towards higher mortality in the CRT group at one‐year follow‐up,” Gopinathannair et al. noted. “Subgroup analysis showed that CRT was not associated with improved survival whether the CF‐LVAD was implanted as bridge‐to‐transplant or as destination therapy.”
In fact, the only variable that was independently associated with increased mortality was the use of amiodarone. Patients on that particular anti-arrhythmic drug demonstrated a 77 percent increased risk of death during follow-up.
Gopinathannair and colleagues suggested multiple factors may have contributed to the lack of benefit from continued CRT after LVAD placement.
“In HF patients with wide QRS duration, the beneficial effects of CRT on LV systolic function and HF symptoms are primarily mediated by correction of electrical dyssynchrony leading to improved mechanical synchrony,” they wrote. “The significant LV unloading following LVAD implantation represents a completely different hemodynamic state and likely supersedes any benefits that CRT can offer. Change in LV myocardial fiber orientation from CF‐LVAD inflow cannula placement as well as alterations in the orientation of cardiac chambers may have diminished any CRT effect.”
In a related editorial, three researchers said this multicenter observational study is a “welcome step forward” in this area where only single-center results have been reported. But they believe a prospective study is warranted as LVAD therapy continues to progress.
“A focus on preventing post‐LVAD complications weighed against the uncertain expectation of benefit for traditional heart failure therapies post‐LVAD is needed,” wrote Justin M. Vader, MD, and Daniel H. Cooper, MD, both with Washington University, St. Louis, and Praveen Rao, MD, with Baylor University Medical Center.
The editorialists also said “perhaps (Gopinathannair et al.) have buried the lede,” considering their primary analysis compared device types but amiodarone was the only variable significantly associated with worse survival.
“While the authors note no significant difference in measured baseline characteristics between amiodarone‐exposed and nonexposed patients, it remains possible that amiodarone was in fact used in patients at higher risk of mortality, patients with greater burden of arrhythmia, and/or greater renal dysfunction prohibitive of other antiarrhythmic drug choices,” they wrote. “It is, however, data that certainly compel the question of when to consider mitigation of amiodarone use for the purpose of avoiding the known long‐term toxicities of the drug.”