Progress of patients with hypertrophic cardiomyopathy treated with alcohol septal ablation

Courtesy of Dr. José Álvarez.

Alcohol septal ablation (ASA) for the treatment of obstructive hypertrophic cardiomyopathy (OHC) is a procedure introduced in 1995 as an alternative to surgical myectomy.

The American College of Cardiology (ACC)/American Heart Association (AHA) guidelines indicate that ASA should be reserved for older patients with comorbidities, thus establishing surgical myectomy as the treatment of choice for young patients, particularly due to uncertainty as regards the long-term evolution of the septal scar caused by ASA.

This study assessed 1197 patients who underwent ASA for OHC, in seven European sites. Patients were divided into groups according to their age: young (≤50 years), middle-age (51 to 64 years), and older (≥65 years).

Thirty-day mortality and pacemaker implantation rates were lower in young patients when compared with older patients (0.3% vs. 2%; p = 0.03 and 8% vs. 16%; p < 0.001).

During a mean follow-up period of 5.4 ± 4.2 years, 165 patients (14%) died.

Annual mortality rates of all three age groups (young, middle-age, and older) were 1%, 2%, and 5%, respectively (p < 0.01). Annual adverse arrhythmic event rates were about 1% for the three groups. Independent predictors of mortality in young patients were age, female sex, and residual left ventricular outflow tract gradient. Young patients treated with ≥2.5 mL alcohol had a higher global mortality rate (0.6% vs. 1.4% per year; p = 0.03).

During the long-term follow-up, 95% of young patients were in New York Heart Association functional class I or II.

The number of reinterventions (ASA or surgical myectomy) was similar for all three groups (11% vs. 10% vs. 7%).

Authors concluded that alcohol septal ablation in younger patients with OHC was safe and effective for symptom relief, and state that the indication for this procedure should be broadened to younger patients.

Editorial Comment

To this date, the referenced study is, as far as we know, the largest series published on OHC patients treated with ASA. This is an observational retrospective study carried out in seven European tertiary sites. Outcomes observed in young population are similar to those observed in older population, except for a lower rate of pacemaker implantation in the former. We should take into account that, proportionally, OHC-related mortality rates are higher among young patients, when compared to older populations, while non-cardiac mortality presents an opposite trend. However, the latter indicator lacks statistical power enough to draw conclusions. The finding that doses higher than 2.5 mL were associated to higher mortality rates should be highlighted.

Courtesy of Dr. José Álvarez.

Original title: Outcomes of Alcohol Septal Ablation in Younger Patients with Obstructive Hypertrophic Cardiomyopathy.

Reference: Max Liebregts, MD, Lothar Faber, MD, Morten K. Jensen, MD, Pieter A. Vriesendorp, MD, PHD, et al. J Am Coll Cardiol Intv 2017; 10:1134–43.

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