Letters to the Editor Severe Subaortic Stenosis in interrupted Aortic Arch To the Editor: I read with great interest the excellent article of Menahem, Brown, and Mee on “Severe subaortic stenosis in interrupted aortic arch in infancy and childhood.”’ Indeed it is a major problem, responsible for the mortality of otherwise correctly repaired interrupted aortic arches (IAA) in the newborn.’ As emphasized by Jonas et a1.,2 the obstruction is complex, often involving the aortic annulus. It is therefore amazing that in some series of consecutive cases, this stenosis or hypoplasia was not encountered at the time of the first procedure3 We also, in a small series of cases (n = 12), had intraoperative mortality due to hypoplastic annulusof the aorta, with inability to come off the pump. In 1990, we performed on a patient a procedure similar to that described in Menahem’s article but probably simpler, and we think easier to perform. The patient had a type B IAA, with an aberrant right subclavian artery (Fig. 1A). The aortic annulus diameter was measured at 4-5 mm by echocardiography, with a diminutive but not stenotic bicuspid aortic valve. At surgery, after dissecting free ascending aorta, the pulmonary artery (PA) and its branches, the patent ductus arteriosus, and descending aorta, cardiopulmonary bypass (CPB) was established between the ascending aorta and right atrium, and hypothermic arrest was performed. The main pulmonary artery was transected at the bifurcation level. The descending aorta was also transected and a complete excision of the ductal tissue was performed (Fig. 18). Reconstruction of the left ventricular outflow tract was done by a direct anastomosis between the PA trunk and the descending aorta after partial closure of the PA to accommodate the anastomosis, the descending aorta being smaller than the proximal PA (Fig. lC), by closure of the ventricular septa1 defect with a patch directing

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the blood of the left ventricle through the aorta and pulmonary artery (Fig. 1D). The pulmonary bifurcation and the right and left branches were dissected free down to both hila, and the bifurcation was placed anteriorly to the newly reconstructed PA trunk-descending aorta anastomosis. A 13-mm hornograft was thein inserted between the right ventriculotorny and the PA bifurcation (Fig. 1D). C P B was easily discontinued, but PA hypertension persisted, and the patient was left open, with closure of the chest with a Silastic membrane. In the postoperative period, the patient remained in pulmonary hypertension despite ventilation and usual therapeutics. Due to improvement of the hemodynamics, he was closed 6 days after the initial procedure. Unfortunately he died of a sudderi unexpected ventricular tachycardia. At necxopsy, the repair seemed to be very adequate. A diffuse pulmonary infection was present, and a septic thrombus of the innominate vein was also found. The problem of aortic obstruction in IAA has been discussed in Menahem’s article’ and the mechanism is well described: posterior displacement of the infundibular septum, narrow annulus, bicuspid valve, subvalvular, fibrous tissue, and ascending aorta hypoplasia are the usual mechanisms. Surgical relief of this obstruction is not satisfactory in the newborn since there is little of the infundibular septum to resect, and since a diminutive aortic annulus has no direct treatment. As emphasized by the authors, it is often only temporary relief requiring reoperation, often as major as a Konno procedure or aortic root replacement. The procedure described by Menahem et al. is an excellent way of permanently relieving the aortic obstruction. \Me describe an alternative operation to the procedure of Menahem at al. Despite the unfavorable outcome in our patient whose death was not related to the procedure used, we think it is a simpler operation, with only one anastomosis between PA and descending aorta. In

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LETTERS TO THE EDITOR

B

A

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Figure 1.

Menahem’s procedure, there are two anastomoses at risk, and both are done on a very small aorta, increasing the danger of anastomotic stenosis. In addition, due to the frequent discrepancy between an enormous PA and a very small ascending aorta, the proximal anastomosis in Menahem’s procedure‘ is probably more difficult to perform than their drawing shows, whereas in our procedure, the PA trunk and the descending aorta are practically in direct continuity, and a wide anastomosis is possible. Dominique Metras, M.D. Bernard Kreitmann, K.B. la Timone Children’s Hospital Marseille, France

REFERENCES 1. Menahem S, Brawn WJ, Mee RBB: Severe sub-

aortic stenosis in interrupted aortic arch in infancy and childhood. J Cardiac Surg 6:373, 1991. 2.Jonas RA, Sell JE, Van Praagh R, et al: Left ventricular outflow tract obstruction associated with interrupted aortic arch and ventricular septal

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defect. In Crupi G, Parenzan L, Anderson RH (eds): Perspectives in Pediatric Cardiology. Volume 2. Pediatric Cardiac Surgery. Mount Kisco, NY, Futura Publishing Company, Inc., 1989, p. 61. 3. Vouhe PR, Mace L, Vernant F, et al: Primary definitive repair of interrupted aortic arch with ventricular septal defect. Eur J Cardiothorac Surg 4:365,1990.

Reply to the Editor: Thank you for the opportunity to reply to the letter by Drs. Metras and Kreitrnann. Their alternative approach in trying to deal with those infants with a small subaortic area and hypoplastic aortic root by the creation of a double outlet left ventricle is similar in concept to what we have described.‘ By performing a “Lecompte type” maneuver, the risk of right pulmonary artery compression by the anastomosis of the main pulmonary artery to the descending aorta is reduced. However, in the technique described, left main bronchus compression is a possibility.

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