Techniques and complications of transaortic subvalvular myectomy in patients with hypertrophic obstructive cardiomyopathy (HOCM).

The natural history of hypertrophic obstructive cardiomyopathy (HOCM) is usually characterized by development of mitral insufficiency, congestive heart failure (CHF) and sudden death. In patients (pts) belonging to at least clinical class III (NYHA) after failed medical therapy (beta-blocking agents and calcium-antagonists) surgery should be considered (by means of transaortic subvalvular myectomy). The history and development of different surgical techniques and procedures has been described in detail since 1958, when Cleland performed the first transaortic subvalvular myotomy. Our surgical series (1963-May 31, 1986) consists of 212 pts (mean age 40 years, range 6-73 years) with typical and atypical HOCM. The total hospital mortality rate was 6.6% (n = 14), which was reduced to 3.8% (n = 6), if only transaortic subvalvular myectomy (TSM) was performed (n = 160). In the group of 52 pts with additional surgical procedures the mortality rate was 15.4% (n = 8). The main problems occurred in pts with additional mitral valve replacement (MVR) (n = 15, three deaths). The rate of HOCM-related complications (secondary VSD, total AV-block, cerebral embolism, intraoperative re-myectomy) and those related to surgery (bleeding, pulmonary embolism, wound dehiscence, septicemia) was low. Therefore TSM for HOCM is a low-risk surgical procedure with a good long-term prognosis. However, in pts with a need for additional surgical procedures, the risk is considerably increased. Subjective impression of the pts and hemodynamic data indicate a clear clinical improvement postoperatively. Concerning long-term survival and reduction of the sudden death rate, our data do not allow a final judgement at the moment.