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Mortality rates decrease for adult hypertrophic cardiomyopathy
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Study findings of long-term outcomes in adults with hypertrophic cardiomyopathy found that disease-related mortality rates have dropped to approximately 0.5% per year due to advances in management of and treatments for the condition.
Adult-onset hypertrophic cardiomyopathy has traditionally been associated with annual mortality rates of up to 6% due to complications, including sudden death and death from HF, according to the study background.
The researchers investigated whether recent advances in management strategy, including implantable cardioverter defibrillators and heart transplantation, have improved survival and clinical outlook in adults with hypertrophic cardiomyopathy.
Barry J. Maron
Barry J. Maron, MD, and colleagues assessed long-term outcomes in 1,000 consecutive adults presenting with hypertrophic cardiomyopathy aged 30 to 59 years (mean age, 45 years) during 7.2 years of follow-up.
Positive trends
Of the 1,000 patients, 92% survived to age 53 ± 9.2 years (range, 32-80), with 91% experiencing no or mild symptoms at last follow-up, Maron, from the Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, and colleagues wrote.
Hypertrophic cardiomyopathy-related death occurred in 4% of patients, for an annual rate of 0.53% per year (mean age at death, 50 years), they wrote. Causes of death included progressive HF (n = 17), arrhythmic sudden death (n = 17), embolic stroke (n = 2) and after hypertrophic cardiomyopathy-related surgery (n = 4). None of those who died had obstructive CAD, angina, MI or ACS.
They also reported that during the study period, 5.6% of patients survived life-threating events, often because of ICD interventions for ventricular tachyarrhythmias (n = 33) or transplantation after advanced HF (n = 18; 0.79%/year).
Of those who died suddenly, six had declined ICD therapy and 11 did not receive ICD therapy because they were judged to be low risk without markers or because they were diagnosed in the 1990s, before ICD became a routine therapy for hypertrophic cardiomyopathy, according to the researchers. Of those who died of HF, 12 declined transplantation, were ineligible or were wait-listed and five died of transplantation-related complications.
The rates of freedom from death related to hypertrophic cardiomyopathy were 98% at 5 years and 94% at 10 years, which are not significantly different from expected all-cause mortality in the general population (P = .25), Maron and colleagues found.
Independent predictors of hypertrophic cardiomyopathy-related mortality or life-threatening events were younger age at diagnosis (P < .001), female sex (P = .023) and increased left atrial dimension (P < .001), they found.
Evolution for the better
In a related editorial, Paolo Spirito, MD, wrote that “in barely one generation of investigators, this disease has evolved from a grim and largely untreatable condition to a treatable disorder associated with a normal or nearly normal life expectancy in most patients.”
Spirito, from the Ente Ospedaliero Ospedali Galliera, Genoa, Italy, attributed the advances to a better understanding of the condition across differing levels of symptoms; and major advances in CV therapy, including ICDs, surgical septal myectomy for relief of HF symptoms in patients with left ventricle outflow obstruction, transplantation, and other supportive mechanical therapies.
The next step, he wrote, is to better discern which patients with hypertrophic cardiomyopathy need an ICD, noting that in the present study, the ratio of total ICDs to ICDs that intervened appropriately was 9:1. “This 9:1 ratio is probably higher that we would like and can be explained by the persisting uncertainties in risk stratification,” he wrote. – by Erik Swain
Disclosure: Maron reports consulting for GeneDx and receiving research support from Medtronic. Spirito reports no relevant financial disclosures.
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