Surgery for biventricular obstruction in hypertrophic cardiomyopathy in children and young adults: technique and outcomes†

OBJECTIVES: Biventricular obstruction in hypertrophic cardiomyopathy (HCM) is uncommon, and some clinicians believe that, when symptoms are refractory to medical treatment, this severe form of HCM is best treated by transplantation. We describe our conventional surgical approach and outcomes to treat biventricular obstruction in HCM. METHODS: From 1993 to 2013, we treated 11 symptomatic patients with biventricular outflow obstruction. Relief of left ventricular (LV) obstruction was obtained by performing a transaortic extended septal myectomy and/or a left apical ventriculotomy. Right ventricular outflow tract (RVOT) obstruction was relieved with patch enlargement in all patients and selective resection of muscle bundles. RESULTS: The mean age at surgery was 13 years (2 months-28 years); of the total, 7 (63%) were males. All were symptomatic with shortness of breath, reduced exercise tolerance or failure to thrive. All patients had preserved biventricular systolic function and systolic anterior motion (SAM) of the mitral valve (9 patients had ≥ moderate mitral regurgitation). Preoperative RVOT and LV outflow tract gradients were 60 ± 18 and 78 ± 24 mmHg, respectively. There were no early deaths. Mitral regurgitation secondary to SAM resolved following LV myectomy. The median follow-up time was 4.6 years (maximum 16.3 years). Eight patients (72%) were in NYHA class I. There have been no late ventricular arrhythmias, sudden deaths, reoperations or heart transplantations at follow-up. CONCLUSIONS: Biventricular obstruction is rare in HCM. Surgical relief of left- and right-sided obstruction can be achieved with good early outcomes. Symptoms are improved at intermediate-term follow-up and sudden death is rare.