Patients With Chemotherapy-Induced Cardiomyopathy Show Improvements in LVEF After Cardiac Resynchronization Therapy

With increased recognition of the link between cancer care and heart disease, more studies are evaluating the interconnectedness of cancer survival, chemotherapy, and heart failure (HF) in patients with active cancer or in survivors of the disease. This is especially in light of the rising incidence of chemotherapy-induced cardiomyopathy (CHIC) due to there being more long-term cancer survivors.

Recently, a team from the University of Rochester Medical Center investigated the effects of cardiac resynchronization therapy (CRT) among cancer survivors, most of them women with breast cancer with CHIC from anthracycline chemotherapies. Women are more susceptible to heart disease post chemotherapy, and patients who have received anthracycline-based chemotherapy are prone to heart muscle damage, stated principal study investigator Valentina Kutyifa, MD, PhD. The study results were published in a recent issue of JAMA.

According to the study authors, CRT is associated with improvements in hemodynamic stress, cardiac perfusion, and metabolism, as well as molecular changes from reverse remodeling, which have all been shown to improve functional capacity, quality of life, and long-term survival, and reduce hospitalization from HF.

The trial’s main objective was improvement in left ventricular ejection fraction (LVEF) from a surgically implanted defibrillator or pacemaker via CRT after 6 months of follow-up. The enrolled patients had an LVEF below 35%, with a median of 29% (the American Heart Association considers less than 40% to be HF); New York Heart Association (NYHA) class II-IV HF symptoms; and a wide QRS complex with CHIC.

The study was conducted in the United States between November 21, 2014, and June 21, 2018, at 12 tertiary centers with cardio-oncology programs. All patients had left bundle branch block, the median age was 64 years, the median age at cancer diagnosis was 52 years, and the median time to HF diagnosis was 13.8 after the last cancer diagnosis. Twenty-six patients received CRT defibrillators and 4, CRT pacemakers; 26 were included in the final analysis.

The results show that post CRT, LVEF at 6 months improved from 28% to 39%, which equates to 39% overall; there was an improvement in NYHA status for 41% at 6 months (19% of patients with class II disease and 69% with class III disease); and 83% had no or mild HF symptoms, also at the 6-month mark.

Limitations included the small sample size, short follow-up, and lack of a control group, although the study authors stated to defer therapy in this group would have been unethical. Because most of the patients had exposure to anthracyclines, the authors believe their results illuminate how CRT can benefit these patients.

“The primary benefit of CRT in this cohort of patients could be due to the direct reversal of mechanical dyssynchrony and the associated improved remodeling of the heart,” they conclude.

Reference

Singh JP, Solomon SD, Fradley MG, et al. Association of cardiac resynchronization therapy with change in left ventricular ejection fraction in patients with chemotherapy-induced cardiomyopathy. JAMA. 2019;322(18):1799-1805. doi: 10.1001/jama.2019.16658.