LONG-TERM RESULTS OF LEFT-VENTRICULAR MYOTOMY AND MYECTOMY FOR OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY

A retrospective analysis of patients with hypertrophic obstructive car diomyopathy treated by left ventricular myotomy and myectomy from 1972 to 1994 is reported, There were 158 patients (81 male and 77 female) with a mean age of 50.2 (+/-17.2) years (range 12 to 80 years), One hu ndred nine patients (69%) were 60 years of age or younger, and 49 pati ents (31%) were older than 60 years, The overall mean follow-up period was 6.1 (+/-4.8) years (range 0.1 to 19.3 years) and was 94% complete , with a cumulative total of 956 patient-years, Preoperative exertiona l dyspnea was present in 84%, chest pain in 70%, presyncope in 54%, sy ncope in 31% and cardiac arrest in 5% of patients, Preoperative cardia c catheterization,vas done in 150 patients, with mitral regurgitation detected in 104 patients (67%). The average maximal provocable left ve ntricular outflow tract gradient was 118 (+/-46) mm Hg (range 25 to 25 0 mm Hg). The average preoperative echocardiographic gradient at rest was 64 mm Bg, 20 mm Hg in the early postoperative period and 10 mm Hg in the late postoperative period, The mean septal thickness was 2.2 (/-0.6) cm, 1.9 (+/-0.7) cm in the early postoperative period (p < 0.05 vs preoperative) and 1.7 (+/-0.5) cm in the late postoperative period (p < 0.05 vs preoperative). The overall 30-day operative mortality ra te was 3.2% (5/158), and 0% for 109 patients 60 years of age or younge r, Causes of death included myocardial infarction and left ventricular free wall rupture, myocardial failure from septal perforation, sepsis , cerebrovascular accident caused by thromboembolism, and delayed card iac tamponade in one patient each, Concomitant coronary artery bypass grafting was performed in 22 patients (19.3% of patients greater than or equal to 40 years of age and mitral valve replacement in 5 patients (3.2%). One hundred nine patients (69%) are alive, 10 patients (6.3%) were lost to follow-up, and 39 patients died (24.7%, including operat ive deaths),Actuarial survivals at 1, 5, 10, and 15 years were 92.4% /-2.2%, 85.4% +/-3.1%, 71.5% +/-4.6%, and 46% +/-9%, respectively, The overall linearized death rate for discharged patients was 1.9%/pt-yr and for cardiac related deaths it was 1.7%/pt-yr. Thirty-nine (36%) of the 109 survivors received P-adrenergic blockers, and 30 (28%) receiv ed calcium channel blockers, Ninety-four patients had improvement in N ew York Heart Association functional class, 10 had improvement in symp toms hut not in functional class, and 5 had no improvement in function al class or symptoms. Neither preoperative hemodynamic values nor rout ine echocardiographic measurements significantly correlated with quali ty of postoperative results, Left ventricular myotomy and myectomy is a safe and reproducibly effective operative treatment for medically re fractory hypertrophic obstructive cardiomyopathy, especially for patie nts 60 gears of age or younger, Improvement in functional class and sy mptoms can be expected in nearly all patients, The results of myotomy and myectomy serve as a standard for comparison with other interventio ns for medically refractory cardiomyopathy.