Operative treatment in hypertrophic subaortic stenosis. Techniques, and the results of pre and postoperative assessments in 83 patients.

Abstract

The results of operative treatment in 83 patients with idiopathic hypertrophic subaortic stenosis (IHSS) are described. Most patients with the disease are asymptomatic, or derive satisfactory symptomatic improvement from nonoperative therapy: administration of propranolol, exerice limitation, control of arrhythmia, etc. Operation is required, however, in 10-15% of patients, those who remain severely symptomatic after nonoperative treatment or who become refractory to it. Operation relieves symptoms in IHSS by relieving obstruction to left ventricular outflow, and for a patient to be considered an operative candidate severe obstruction must be documented at left heart catheterization either under resting conditions or after provocative interventions. All 83 patients were severely incapacitated--58 in Class III and 24 in Class IV. Seventy had obstruction at rest (average gradient 96 mm Hg), and 13 had only provocable obstruction. At operation the hypertrophic interventricular septum was exposed via an aortotomy, and a vertical bar of muscle was resected between parallel myotomy incisions. There were six operative deaths (7%); no patient has died since 1970. Seven patients have died late after operation, five of them from causes unrelated to their heart disease or the operation. All surviving patients describe symptomatic improvement. Fifty-two patients with obstruction at rest preoperatively (average gradient 95 mm Hg) have been studied postoperatively: no resting gradient was evident in 47, while in the remaining five the gradient was less than 25 mm Hg. Recurrence of obstruction has never been observed at late catheterization (21 pts) or late echocardiographic examination (37 pts). Obstruction could not be provoked postoperatively in ten of the 11 patients who had large gradients only with the Valsalva maneuver or isoproterenol administration preoperatively. Obstructed and provocable obstructed patients had similar symptomatic improvement after operation. A variety of rhythm and conduction abnormalities were observed both pre and postoperatively, and these are described in detail. The results of operation in these 83 patients with IHSS demonstrate that gratifying symptomatic and hemodynamic improvement uniformly follows left ventriculomyotomy and myectomy. Relief of obstruction and amelioration of symptoms have proved to be long-lasting during postoperative observation periods extending to 14 years. Continued application of the operative procedure in properly selected patients appears to be indicated.

Role of Transcoronary Ablation of Septal Hypertrophy in Patients With Hypertrophic Cardiomyopathy, New York Heart Association Functional Class III or IV, and Outflow Obstruction Only Under Provocable Conditions

“…[1][2][3][4] The therapy most widely applied is surgical myectomy by removing a small amount of muscle from the basal interventricular septum. [5][6][7][8][9] Surgery substantially reduces the subaortic outflow gradient in Ͼ90% of patients and results in persistent symptomatic improvement in Ϸ70% to 90%. [1][2]4,[7][8][9][10] In recent years, transcoronary ablation of septal hypertrophy (TASH) by selective transcatheter septal branch injection of ethanol has been shown to substantially reduce outflow obstruction in 80% to 90% and symptoms in 84% to 90% of patients.…”

Cardiomiopatia hipertrófica tratada por técnica intervencionista de redução septal

“…Diversas intervenções cirúrgicas são classicamente empregadas em pacientes refratários ao tratamento clínico, quando o gradiente se torna >50mmHg em repouso [6][7][8] , assim, a miotomia e miectomia septais, com ou sem concomitante substituição valvar mitral 9,10 . Este último método cirúrgico, usualmente mandatório para insuficiência mitral grave, também pode ser utilizado com a intenção de abolir a participação da válvula na criação do gradiente obstrutivo intraventricular 11 .…”

Surgical treatment for hypertrophic cardiomyopathy: a historical perspective

“…By 1975, Morrow et al had operated on a total of 83 patients, using the parallel incisions approach with small refinements to his technique ( Figure 3) (20). Instead of using a malleable finger-knife to make the initial superficial myotomies, the two parallel incisions were now made with a No.…”

“…The result was a "rectangular channel about 1×1.5 cm" and 4 or 5 cm in length originating from just below the aortic annulus towards the midventricle. Morrow put less emphasis on the length of resection, but rather focused on the depth of the incision, which was a function of the preoperative septal thickness (20,21).…”

“…Indeed, Cooley and associates advocated mitral valve replacement to relieve outflow tract obstruction in patients with HCM (28,29), and while excision of the anterior leaflet corrects obstruction, it leaves the patient with the late hazards of a mitral valve prosthesis. Morrow, however, was a firm believer that intervention on a structurally normal mitral valve was rarely necessary in HCM, even those with hemodynamically important mitral valve regurgitation (20,21).…”