Subaortic stenosis after repair of complete atrioventricular septal defect: anatomic and technical issues

Objective: We reviewed our institutional experience with subaortic stenosis developing after repair of complete atrioventricular septal defects (CAVSD) and analyzed whether subaortic stenosis (SAS) is anatomically inherent or technically-induced.

Methods: Between 1986 and 2012, 383 patients (median age 2.15 years, range 0-4.7 years) underwent biventricular correction of CAVSD. During a median follow-up of 16.06 years, 89 (23.8%) patient underwent first reoperations, 33 (8%) underwent second reoperations, while 20 (5%), 10 (2.6%), 6 (1,6%) and 5 (1.3%) have had third, fourth, fifth and sixth reoperations, respectively. The most common causes of reoperations are left atrioventricular valve regurgitation, residual VSD, SAS and late onset complete heart bock.

Results: Nineteen patients (median age 6.25 years, range 0 to 23 years) developed SAS. They had 26 reinterventions within 6 months-23 years after the initial surgery. Seventeen patients had severe subaortic stenosis (mean pressure gradient of 80± 20 mmHg) to warrant resection of the left ventricular outflow tract obstruction. A spectrum of surgical approaches have been employed and this will be described in detail as to which techniques employed have led to a higher incidence of SAS. Freedom from reoperation is 100%, and 17.6% at 30 days and 15 years, respectively. Cumulative survival is 100% at 30 days and 81.3% at 16 years.

Conclusions: The risk of developing subaortic obstruction after repair of the CAVSD is real and may occur commonly than previously reported. Anatomical and technical issues during the initial CAVSD correction should be meticulously dealt with to reduce the incidence of SAS.