Supravalvar pulmonary stenosis following the arterial switch operation for complete transposition: aetiological and surgical considerations

Abstract

From January 1988 through to July 1994, 54 consecutive infants underwent an arterial switch operation for simple or more complex forms of complete transposition (concordant atrioventricular and discordant ventriculo-arterial connections). They ranged in age from 2 to 180 days. The Lecompte maneuver was performed in all. In the first 19 patients the harvested sinuses of Valsalva were filled with two separate patches of autologous preserved pericardium, while, in the last 35 patients, a wide pantaloon patch of tanned pericardium was employed. Five babies died within 30 days after the procedure (operative mortality of 9.2%, 70% CL 4-17%). Four survivors were found to have developed a significant supravalvar pulmonary stenosis from 1 month to 21 months postoperatively. Echocardiographic data showed a transpulmonary peak systolic gradient from 60 mmHg to 101 mmHg, with a right-to-left ventricular systolic pressure ratio from 0.65 to 0.9-Reoperation was performed from 8 months to 39 months after the arterial switch procedure. Supravalvar pulmonary stenosis was located at the level of the pulmonary trunk, extending distally in two cases, due to the growth of fibrous scarring tissue with partial calcification. The pulmonary valvar leaflets were involved in two cases. Relief of the obstruction was obtained by insertion of a wide shield-tailored polytetrafluoroethylene patch after making an inverted Y-shaped longitudinal incision in the pulmonary trunk between the anterior sinuses of Valsalva. No mortality occurred at reoperation. Early and midterm echocardiographic measurements showed the effectiveness of this technique, with only trivial or mild residual transpulmonary gradients.

Challenges facing the child, adolescent, and young adult after the arterial switch operation

“…Supravalvar pulmonary stenosis is widely recognized as the most frequent anatomic complication of arterial repair. 18,24,[26][27][28] Re-intervention because of such stenosis is needed in between one-twentieth and onethird of patients, with most institutions fortunately reporting a decreasing incidence of this complication with increasing experience with the operation. The peak incidence for reintervention occurs within the first year after the operation, 18 but there appears to be a continuing risk for reintervention throughout the duration of follow-up.…”

“…18,24,[29][30][31] Several risk factors have been defined for this complication, including non-neonatal repair, the presence of longstanding banding of the pulmonary trunk, certain coronary arterial patterns, associated defects, and the surgical technique used for pulmonary reconstruction. 18,[28][29][30] The presence of a hypoplastic aortic root, which becomes the pulmonary root after the switch, has also been reported as a risk factor for pulmonary stenosis, 30 since growth of the old aortic valve in its new pulmonary position may not be normal. 29 In addition to the haemodynamic burden of supravalvar pulmonary stenosis, there have been isolated case reports of haemolysis, 32 formation of false aneurysms, 33 and endocarditis 34,35 due to supravalvar obstruction following the arterial switch.…”