Surgical treatment of idiopathic hypertrophic subaortic stenosis with other cardiac pathology

ABSTRACT

Twenty-nine patients underwent surgery for idiopathic hypertrophic subaortic stenosis (IHSS) solely or in combination with other cardiac pathology. Fifteen men and 14 women, 26 to 75 years of age (mean 56 years), had peak subvalvular gradients, with or without provocation, ranging up to 220 mm Hg (mean 93 mm Hg). The diagnosis of IHSS was confirmed preoperatively by echocardiography in the 23 patients on whom it was performed. Twentyseven patients underwent left ventricular septal myectomy (LVSM), one had a left ventricular myotomy, and another received mitral valve replacement (MVR) alone for palliation of IHSS. In addition, coronary artery bypass (CAB) was performed in 18 of these IHSS patients: 8 had single grafts, 5 had two, 4 had three, and one patient had five grafts. Other operations included MVR in 3 patients, aortic valve replacement, excision of a subaortic membrane, and tricuspid annuloplasty in one patient each. One operative death (3%) occurred 34 days postoperatively. There have been 2 late deaths: one at 22 months from bacterial endocarditis on a prosthetic mitral valve, and another suddenly at 29 months after septal myectomy. After a follow-up ranging from 2 to 93 months (mean 25 months), 22 of 26 patients are asymptomatic. Three asymptomatic patients have been recatheterized 12, 14, and 21 months, respectively, after operation. Marked amelioration of subaortic gradients was noted, and patent grafts were found. Left ventricular septal myectomy (LVSM) can be combined with other cardiac operations to provide effective palliation.