Discrete subaortic stenosis: Assessing adequacy of myectomy by transesophageal echocardiography

Background: Membranectomy and myectomy are standard therapy for discrete su baortic stenosis (DS) and are associated with low rates of endocarditis, re currence, and aortic insufficiency. Extensive myectomy increases risk of co mplications such as conduction tissue damage and iatrogenic ventricular sep tal defect (VSD). Materials and Methods: Forty-five adult patients with DS underwent operations in Gulhane Military Medical Academy. Exertional dyspne a was the principal symptom in 29 (64.4%) patients. Transesophageal echocar diography (TEE) was performed routinely in all patients to assess the lengt h and depth of needed myectomy during the perioperative period. Aortic insu fficiency (Al) was also noted preoperatively in 31 (68.9%) and a history of aortic valve endocarditis was present in 4 (8.9%) patients. Results: Myect omy was performed according to TEE measurements. An average of 10 mm in wid th, 10 mm in depth, and 2.3 mm in length of septal tissue was resected. The mean left ventricle-aorta peak systolic gradient decreased from 70.2 +/- 9 .7 to 17.2 +/- 2.7 mmHg (p < 0.001). Aortic valve repair was performed in 8 (7.8%) patients and aortic valve replacement in 11 (24.4%) patients at the initial operation. latrogenic VSD did not occur in any of the patients. Av erage postoperative left ventricular outflow tract diameter was 21 +/- 1.5 mm. Temporary complete heart block occurred in three patients. There was an early residual gradient (36 +/- 8 mmHg) resulting from temporary hypercont raction that decreased (18 +/- 5 mmHg) in the first postoperative day. Conc lusions: Myectomy under perioperative TEE measurement is safe and effective in the treatment of DS. TEE-guided myectomy reduces complications such as complete heart block and iatrogenic VSD.