Who and how to treat with non-surgical myocardial reduction therapy in hypertrophic cardiomyopathy: long-term outcomes.

Abstract

Iatrogenic infarction of the hypertrophic intraventricular septum in hypertrophic obstructive cardiomyopathy has become an accepted treatment for patients refractory to medical treatment and/or pacemaker therapy. During the 8 years of its existence, non-surgical myocardial reduction (NSMR), which is based on the injection of absolute alcohol into the first or second septal perforator originating from the left anterior descending coronary artery, has been used more frequently than surgical myectomy. The advantages of this catheter procedure are local anesthesia, short hospital stay, and less morbidity as compared with open heart surgery. Patients with an interventricular septal thickness of at least 18 mm, left ventricular outflow tract gradient at rest of at least 30 mmHg, and an intraventricular gradient during provocation (such as isoproterenol, dobutamine, amylnitrate, and postextrasystolic potentiation) are potential candidates for this procedure. Important mitral valve abnormalities must be excluded prior to septal ablation with alcohol. In some patients, the coronary anatomy is unsuitable for this procedure. Mid-to-long-term results have shown very significant intraventricular gradient reduction, symptom improvement, reduction in left ventricular filling pressure and pulmonary artery pressure, and increase in exercise capacity. Complications, such as the need for long-term pacing, have fallen with the reduction of the total amount of injected alcohol and the use of contrast echocardiography. NSMR appears to be effective, and can be used as an alternative to classical surgical myectomy in symptomatic patients resistant to conservative treatment.