Surgical treatment results of secondary tunnel-like subaortic stenosis after congenital heart disease operations: A 7-year, single-center experience in 25 patients

Objective To summarize the surgical results of secondary tunnel-like subaortic stenosis (STSS) after congenital heart disease (CHD) operations, the pathogenesis of STSS is analyzed and its operative effect and prognosis are evaluated. Methods We analyzed clinical data from 25 patients who underwent surgical repair for STSS in Fuwai Hospital from 1 January 2009 to 31 December 2015. There were 17 males and 8 females. The types of CHD included a double outlet right ventricle (DORV), a ventricular septal defect (VSD), and partial atrioventricular septal defects (PAVSDs). The median age of the patients at the time of their first CHD operation was 1 year (1 month to 42 years). The median age of the patients at the time of STSS repair was 5 years and 8 months (2 years and 10 months to 48 years). The surgical types included the modified Konno procedure, Konno procedure, fibromuscular resection (FMR), and removal and reconstruction of the intraventricular baffle (RRIB). Results All patients successfully received STSS repair. There were no surgical deaths in this study. The preoperative gradient across the left ventricular outflow tract was 81 (43-159) mm Hg, and the postoperative gradient was 8.2 (4-46.2) mm Hg. On the basis of the surgical techniques used for subaortic stenosis repair, we divided the patients into three subgroups: the Konno group (n = 11), the FMR group (n = 11), and the RRIB group (n = 3). Preoperatively, there was no significant difference in the gradient between the Konno group and the FMR group (Delta P, P = .287), but the Konno group was significantly better than the FMR group postoperatively (Delta P, P = .022). There were no significant statistical differences between the RRIB group and the other two groups in all these data. A third-degree atrioventricular block occurred in two patients after the operation, and both patients required a permanent pacemaker. All patients were followed up after discharge for a median duration of 5 years (3-9 years). During the follow-up period, none of the patients had any clinical symptoms or subaortic restenosis, and there was no late death. Conclusions Secondary subaortic stenosis (SSS) occurs after DORV surgery. The Konno operation or the RRIB can be selected for surgical correction, which is more satisfactory and safer for the treatment of stenosis. For patients with SSS after the operation of VSD or PAVSD, the FMR can be chosen for the operation. The operation is relatively simple, the operation time is short and the effect is satisfactory. Existing problems include that the incidence of a third-degree atrioventricular block is slightly higher after the operation.