Survival After Septal Ablation for HOCM Similar to General Population

 

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Highly symptomatic patients who undergo alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) have long-term survival rates comparable to those of the general population, according to a study published online January 24, 2014, ahead of print in the European Heart Journal.

Josef Veselka, MD, of University Hospital Motol (Prague, Czech Republic), and colleagues evaluated outcomes for 178 consecutive, highly symptomatic patients who underwent alcohol septal ablation for HOCM between April 1998 and April 2013. Mortality outcomes were compared with expected survival of an age- and sex-matched general population.

In-hospital mortality was 0.6%, the result of 1 death due to pulmonary embolism. Ablation-related mortality was 1.1%. Sustained ventricular arrhythmias occurred during index hospitalization in 6 patients (3%), and all required immediate electrical cardioversion. A total of 25 patients (14%) developed periprocedural complete heart block. No patients required urgent surgical operation. Repeat alcohol septal ablation was performed in 6 patients (3%), and 2 patients (1.1%) underwent surgery after ablation for myectomy or valvular heart disease.

Symptom Improvement Observed

At baseline, approximately 87% of patients had dyspnea with NYHA functional class 3 or 4, 81% had a combination of dyspnea and angina, and 15% experienced repeated syncopes. At a median follow-up of 4.8 years, 89% of patients had a reduction of dyspnea ≥ 1 NYHA functional class. Other measures of symptomatic status also were reduced (table 1).

Table 1. Symptomatic Outcomes

 

At follow up, residual LV pressure gradient ≤ 30 mm Hg was present in 85% and mean decrease of LV pressure gradient was 70%.

There were 19 deaths (11%) during 925 patient-years, resulting in an overall annual mortality rate of 2.1%. The main causes of death were stroke (42%), sudden death (21%), and cancer (21%). Survival free of all-cause mortality was:

• 97% at 1 year
• 92% at 5 years
• 82% at 10 years

This observed mortality was comparable to that of the expected survival for the general population matched for age and sex (P = 0.08). In multivariate analysis, the only independent predictor of all-cause mortality was age at time of procedure (HR 1.09; 95% CI 1.04-1.14; P < 0.01). Additionally, multivariate analysis to identify the predictors of all-cause mortality combined with appropriate ICD discharge identified higher age (HR 1.08; 95% CI 1.04-1.13; P < 0.01) and preablation septum thickness (HR 1.20; 95% CI 1.06-1.36; P < 0.01).

Reassuring in the Long Term 

In a telephone interview with TCTMD, Sorin J. Brener, MD, of Weill Cornell Medical College (New York, NY), explained that the concern regarding long-term safety of (ASA) has been that the scar created by the procedure must be substantial enough to relieve obstruction, yet not increase risk of sudden cardiac death.

He said the results of the study are in line with those from a few other published cohorts, but considering that some patients in the Czech study were followed for as long as 15.1 years, the long-term safety of the therapy can be considered “very reassuring.”

“These are patients who are on maximally tolerated medication regimens, and they are still severely symptomatic so . . . it’s good to see results from well put together studies like this,” Dr. Brener continued. “In addition to very good symptom relief, they have good survival.”

The study authors add that the causes of death seen in their population “suggest that discussion about the long-term risks of post-ASA ventricular arrhythmias and the general risk of sudden death . . . may overshadow the importance of other therapeutic aspects of [HOCM] management.” They note that their study provides additional evidence that the most common cause of hypertrophic cardiomyopathy-related death in patients age 60 or older appears to be stroke.

“Therefore, the focus during follow-up of [HOCM] patients should be drawn to detection and treatment of atrial fibrillation in order to reduce the high number of strokes,” they write.

Finally, Dr. Veselka and colleagues say their study, with 1 of the longest follow-up periods reported to date, demonstrates that “symptomatic improvement after ASA seems to be remarkable and durable.”

Study Details

A temporary pacemaker was placed in the right ventricle in all patients without previous permanent pacemaker implantation. Alcohol ablation was guided by myocardial contrast echocardiography; an injection of desiccated alcohol 96% was usually followed by a decrease in pressure gradient. Patients were observed in the coronary care unit for 2 or more days. The pacemaker lead was then removed if no episode of high-degree atrioventricular block occurred.

 

 

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Source:Veselka J, Krejčí J, Tomašov P, et al. Long-term survival after alcohol septal ablation for hypertrophic obstructive cardiomyopathy: A comparison with general population. Eur Heart J. 2014;Epub ahead of print.

 

 

 

 

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