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Nonsurgical Septal Reduction in HCM

A catheter-based approach holds promise for treating drug-refractory outflow obstruction in hypertrophic cardiomyopathy, but a study of the approach lacks complete long-term follow-up for many subjects.

The editors of the New England Journal of Medicine have retracted publication of the article on which this review is based.

In patients with hypertrophic cardiomyopathy (HCM), dynamic obstruction of the left-ventricular outflow tract (LVOT) can cause substantial disability and does not always respond to drug therapy. One treatment option is a catheter-based technique that involves injecting 100% ethanol into the septal perforator branches of the left anterior descending artery to cause a controlled infarction of the interventricular septum. Short-term studies have suggested that this procedure may be effective, but long-term data are sparse.

In this multicenter study, investigators evaluated 64 consecutive patients (mean age, 48; 30% female) who underwent this procedure for hypertrophic cardiomyopathy (HCM) with drug-refractory symptoms. Over the course of the entire study, it appears that 4 patients were lost to follow-up and that another 18 had incomplete long-term follow-up data.

From preprocedure to 6 weeks postprocedure, mean resting LVOT gradient decreased from 64 to 16 mm Hg, mean exercise time increased from 6.1 to 9.5 minutes, and mean peak oxygen consumption increased from 18.4 to 29.3 mL/kg/min. NYHA class also improved significantly.

During a mean 3-year follow-up, no deaths occurred. In the 42 patients with complete 3-year follow-up data, improvements in resting LVOT gradient, exercise parameters, and NYHA class were similar to the 6-week results. No patient's LVOT gradient worsened over time. Complete heart block, the most common major complication, did not appear to affect long-term outcomes substantially.

Comment: This study documents the long-term benefits (in 42 patients) of a catheter-based approach to treating drug-refractory outflow obstruction in HCM. In an accompanying piece, Eugene Braunwald lauds the success but issues several cautions, including that the learning curve for performing this technique is steep, that the mortality risk associated with the "controlled" infarction is similar to that of surgery, and that many patients develop complete atrioventricular block. The study authors call nonsurgical septal reduction "an investigational therapeutic procedure."

— Harlan M. Krumholz, MD, SM

Published in Journal Watch Cardiology December 6, 2002

Citation(s):

Shamim W et al. Nonsurgical reduction of the interventricular septum in patients with hypertrophic cardiomyopathy. N Engl J Med 2002 Oct 24; 347:1326-33.

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Braunwald E. Hypertrophic cardiomyopathy -- The benefits of a multidisciplinary approach. N Engl J Med 2002 Oct 24; 347:1306-7.

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Curfman GD et al. Notice of retraction. N Engl J Med 2003 Mar 6; 348:945.

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Coats AJ et al. Retraction: Shamim et al. Nonsurgical reduction of the interventricular septum in patients with hypertrophic cardiomyopathy. N Engl J Med 2002;347:1326-33. N Engl J Med 2003 Mar 6; 348:951.

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