Arterioplasty for Right Ventricular Outflow Tract Obstruction After Arterial Switch Is a Durable Procedure.

BACKGROUND

Right ventricular outflow tract obstruction (RVOT) is the most common late complication requiring intervention after arterial switch operation (ASO). The durability of surgical management of this complication has not been well established.

METHODS

We retrospectively reviewed the charts of 38 consecutive patients who underwent RVOT reconstruction after ASO at our institution between 2004 and 2013. During the same time period, 223 consecutive patients underwent ASO for transposition of the great arteries at our institution. Thirty-five (16%) of the 223 patients developed RVOT obstruction, and 3 additional patients who had ASO done elsewhere presented to us with RVOT obstruction. Patient characteristics, site of stenosis, type of intervention, and outcomes were analyzed. Data are presented as median with interquartile ranges.

RESULTS

The time interval between ASO and echocardiographic diagnosis of significant RVOT obstruction was 12.5 (3 to 23.7) months. After echocardiographic diagnosis, 33 (87%) children underwent cardiac catheterization. Obstruction involved the supravalvar main pulmonary artery (PA) in 21 (64%), branch PA in 14 (42%), pulmonary valve in 4 (12%), and sub-valvar area in 1 (3%). Ten of 33 patients who underwent catheterization had attempted percutaneous intervention, with 4 (40%) demonstrating significant response. Surgical intervention was performed at a median of 4 months in responders compared with 2.3 months in non-responders. Surgical repair included main PA plasty (36), extended to 1 or both branch PAs (26), or crossed the RVOT annulus (7). Surgical morbidity was 13% and there was no hospital or late mortality. At last follow-up, 41.2 months (21.4 to 81) after RVOT reconstruction, all patients had New York Heart Association grade 0 or 1 symptoms, and RV pressure was a median 36% of systemic pressure. Five (13%) patients underwent catheterization 26 months after surgery, with 2 requiring dilation at site of arterioplasty and 3 requiring distal branch PA intervention. One patient required reoperation for main PA stenosis. Freedom from re-intervention after surgery is 89%, 86%, and 86% at 2, 3, and 5 years, respectively.

CONCLUSIONS

Surgical management of RVOT obstruction after ASO is an effective and durable intervention in the intermediate term. Our results serve as a benchmark for expected outcomes in this disease process.