Surgical Technique in Subvalvular and Midventricular Hypertrophic Obstructive Cardiomyopathy (HOCM)

Abstract

Cleland, in 1958 performed the first subvalvular myotomy for relief of hyper-trophie obstructive cardiomyopathy (HOCM); following him came a variety of surgical procedures. In our clinic we principally use the Morrow technique (subvalvular myectomy) which was modified for better initial pressure gradient reduction, improvement of diastolic relaxation, and decrease of concomitant mitral insufficiency. Since 1963 a total of 253 patients were operated upon for symptomatic HOCM (NYHA class III or IV) after failing medical therapy (β-blockers, calcium antagonists). Their mean age was 41–45 years (range, 6–74 years). The male/female radio was 1.7 : 1. In 230 patients a typical subvalvular significant obstruction was present, while 23 patients had an additional, atypical midventricular obstruction. The surgical steps for both variations of HOCM are described in detail. The hospital mortality for transaortic subvalvular myectomy was 3.2% (6 of 190 patients), while for patients needing additional cardiac procedures it was 12.7% (8 of 63 patients). Taking account of the natural history of HOCM involving continuing deterioration, all patients were followed postoperatively (100%). The yearly death rate (HOCM-related) was 1.2%. However, the majority of the surviving patients (more than 6 months) demonstrated considerable long-term clinical improvement regarding complaints, physical capacity, and hemodynamics. Thus, operative relief of symptomatic HOCM is of long-term benefit for the patients.