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Cardiac drugs show cardioprotective benefit in boys with muscular dystrophy
The addition of eplerenone to background therapy with ACE inhibitors or angiotensin receptor blockers was associated with a decline in the progression to left ventricular systolic function in boys with Duchenne muscular dystrophy and preserved ejection fraction.
“With increasing recognition of the effect of cardiomyopathy on morbidity and mortality in Duchenne muscular dystrophy, improved strategies are needed to change the natural history of declining left ventricular systolic function and to attenuate its sequelae,” researchers wrote
The randomized, double blind, placebo-controlled trial included 42 boys aged 7 years and older with Duchenne muscular dystrophy, myocardial damage by late gadolinium enhancement cardiac MI and preserved EF. The patients were randomly assigned 25 mg oral eplerenone (n=20) or placebo (n=22), on top of background therapy with ACE inhibitors or angiotensin receptor blockers.
Dosing was once daily every other day for 1 month and then increased to once daily if the patient maintained normal potassium concentrations.
Follow-up visits were conducted at 6 and 12 months, during which cardiac MRI was performed. Serum potassium levels were obtained at baseline and at 1, 3, 6, 9 and 12 months.
The primary outcome was change in LV circumferential strain at 12 months.
Twenty patients in each group had follow-up visits at 6 and 12 months. Patients assigned eplerenone had significantly less decline in LV circumferential strain at 12 months vs. patients assigned placebo (median change, 1% vs. 2.2%; P = .02). Decreases in EF were significantly greater in the placebo group (–3.7% vs. –1.8%; P = .032). The researchers noted that the decline in cardiac function and structure was not significantly attenuated in the eplerenone group until patients had received at least 6 months of therapy.
Neither group exhibited abnormal cystatin C, troponin-I, creatinine kinase or potassium concentrations during the study period.
One patient assigned placebo died due to a fat embolism during the study and another patient assigned placebo withdrew due to pre-existing digestive issues. Other observed adverse events were mild, including headaches coinciding with seasonal allergies in one patient assigned eplerenone, flushing in one patient assigned placebo and an anxiety attack in another patient assigned placebo.
“Our findings suggest that early treatment with eplerenone attenuates decline in cardiac function, which is a leading cause of death in Duchenne muscular dystrophy,” the researchers wrote. “Although the fundamental goal of this study was to test the use of early intervention with available drugs in a disorder in which patients are likely to have progressive cardiomyopathy, the need for long-term clinical follow-up is apparent when recognizing that hard events, such as cardiac failure and death, are unlikely to occur for many more years.”
Disclosure: The study was funded by BallouSkies, Parent Project for Muscular Dystrophy, the US National Center for Advancing Translational Sciences and the NIH. See the full study for a list of relevant financial disclosures.