Percutaneous Septal Ablation for Hypertrophic Obstructive Cardiomyopathy Shows Low Mortality

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In patients with hypertrophic obstructive cardiomyopathy, a percutaneous procedure in which alcohol is injected to occlude a septal branch produces low in-hospital mortality as well as sustained hemodynamic and systematic effects, concludes a study published online May 3, 2011, ahead of print in Circulation Cardiovascular Interventions.

From 1999 to 2010, researchers at 4 European centers led by Morten Kvistholm Jensen, MD, of Copenhagen University Hospital (Copenhagen, Denmark), performed 313 percutaneous transluminal septal myocardial ablation (PTSMA) procedures in 279 patients. Procedures were guided by transthoracic or transesophageal echocardiography and done using intracoronary echocardiography contrast. The alcohol was injected slowly during a period of 5 to 10 minutes, and then the balloon was kept inflated for 10 minutes. By the end of the study period, the standard alcohol dose injected was 0.1 mL per mm septum thickness per septal branch.

A high percentage of patients (69%) had 1 or more comorbidities including: obesity, chronic obstructive pulmonary disease (COPD), diabetes, history of arterial hypertension, cerebrovascular events, and valve disease. Each patient underwent between 1 and 8 follow-up assessments, at which time symptoms and functional class were documented.

Younger Age Predicts Survival

At 1 year, the median of left ventricular outflow tract gradient at rest was reduced from 58 mm Hg at baseline to 12 mm Hg (P < 0.001), with a small further decrease of 0.9 mm Hg per year during the follow-up period (P = 0.03). In addition, the proportion of patients with syncope decreased from 18% to 2% (P < 0.001), and the prevalence of New York Heart Association (NYHA) class III/IV was reduced from 94% to 21% (P < 0.001). Left ventricle ejection fraction was 59 ± 7% at baseline and 58 ± 9% at 1-year follow-up (P = 0.08) and remained stable during the follow-up period (P = 0.2).

In 21% of patients, dyspnea (NYHA class III/IV) persisted despite successful reduction of the left ventricular outflow tract obstruction. The condition was associated with diabetes (P = 0.03), COPD (P = 0.02), and valve disease unrelated to hypertrophic cardiomyopathy (P < 0.01). Within 2 years, 14% of patients required reintervention, either myectomy or PTSMA.

In-hospital mortality was 0.3%, and 30-day mortality was 0.6%. In-hospital ventricular fibrillation occurred in 2.8% of patients during the PTSMA procedure or during monitoring.

Patients aged less than 60 years had the best survival. However, patients both younger and older than 60 years had survival rates similar to those of age- and sex-matched controls (table 1).

Table 1. Survival Rates After PTSMA

^a Each group vs. its matched background population.

In multivariable analysis, baseline age was the sole predictor of survival (HR 1.07; 95% CI 1.03-1.1; P < 0.001), but female sex, chronic obstructive pulmonary artery disease and the sum of arrhythmic events during in-hospital monitoring showed no association with mortality.

Dr. Jensen and colleagues say the low in-hospital mortality rate suggests “that a careful PTSMA strategy, which may necessitate [repeat treatment] in selected cases, can be considered safe.”

Moreover, the study observed 1,142 patient years, and its size may help level out differences in local routines, operator skills, medication, permanent pacemaker or implantable cardioverter-defibrillator use, and follow-up. “Thus, the results of our multicenter study may be more generalizable than those from single-center studies,” they conclude.

 

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Source:
Jensen MK, Almaas VM, Jacobsson L, et al. Long-term outcome of percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: A Scandinavian multicenter study. Circ Cardiovasc Interv. 2011;Epub ahead of print.