MODIFIED KONNO-RASTAN PROCEDURE FOR SUBAORTIC STENOSIS - INDICATIONS,OPERATIVE TECHNIQUES, AND RESULTS

Background. Diffuse or unresectable subaortic stenosis (SAS) necessita tes an aggressive surgical approach for the elimination of left ventri cular outflow tract obstruction. In this article we report our experie nce with the modified Konno-Rastan procedure, with inherent preservati on of the native aortic valve and annulus, in the treatment of diffuse or unresectable SAS. Methods. Sixteen children (age range, 21 months to 18 years) underwent the modified Konno-Rastan procedure through eit her a transventricular (n = 12) or a transatrial approach (n = 4) to t he conal septum. Indications for operation were recurrent SAS (n = 3), hypertrophic obstructive cardiomyopathy (n = 3), tunnel stenosis (n = 2), SAS related to a canal (n = 3), and SAS after ventricular septal defect closure(n = 5). Eleven patients had undergone previous procedur es and 5 underwent the modified Konno-Rastan procedure as their primar y operation. Results. The mean preoperative left ventricular outflow t ract gradient of 50 +/- 17 mm Hg was reduced to 3 +/- 7 mm Hg (p < 0.0 01) after surgical repair. Postoperative complications included sterna l infection (n = 1), heart block (n = 2), mediastinal bleeding (n = 1) , and renal and cerebral ischemia (n = 1). There was 1 late postoperat ive death caused by pneumonia 2 years after operation (6.2% mortality rate). The mean follow-up period was 62 +/- 39 months and all patients had complete relief of preoperative symptoms and were in New York Hea rt Association class I. One patient underwent a successful redo modifi ed Konno-Rastan procedure 7 years after the first operation for residu al left ventricular outflow tract obstruction immediately below the ao rtic valve. One patient is awaiting reoperation for aortic incompetenc e unrelated to conal enlargement 1.5 years after the first procedure. Conclusions. The modified Konno-Rastan procedure represents an excelle nt therapy for diffuse or unresectable SAS in patients with a normal a ortic valve. In addition, it produces excellent results in a limited n umber of patients with hypertrophic obstructive cardiomyopathy, in who m the Morrow procedure traditionally has been performed. Although it u sually is performed through a transventricular approach, the modified Konno-Rastan procedure also can be performed through a transatrial app roach; this is particularly useful in patients who have had previous v entricular septal defect closure associated with SAS occurring proxima l to the prosthetic patch. (C) 1998 by The Society of Thoracic Surgeon s.