Switch back: Using the pulmonary autograft to replace the aortic valve after arterial switch operation

Aortic valve insufficiency has been described to occur after the arterial switch operation. Valve insufficiency is mild in most cases. In some patients valve repair or root reconstruction may solve the problem, but in others the valve will have to be replaced. Inasmuch as the number of patients surviving the arterial switch operation is growing, valve insufficiency may be seen more often. In infants the ideal way to replace the aortic valve is by using a pulmonary autograft. Our experience with aortic valve replacement using a pulmonary autograft (former aortic valve) in one infant with a history of arterial switch operation is described. A little girl, 3 years 4 months old, was referred to us from another institution. At the age of 2 days an arterial switch operation was performed for simple transposition of the great arteries. The coronary anatomy was normal (1LCx-2R, Leiden classification).1Gittenberger-de Groot AC Sauer U Oppenheimer-Dekker A Quaegebeur JM. Coronary arterial anatomy in transposition of the great arteries: a morphological study.Pediatr Cardiol. 1983; 4: 15-24Google Scholar The aorta was anterior to the pulmonary artery. Both semilunar valves were tricuspid and normal. The coronary arteries were excised together with U-shaped aortic wall buttons and implanted in the pulmonary artery base by means of the trapdoor technique. The neopulmonary root was reconstructed with a pantaloon-shaped patch of autologous pericardium. A Lecompte maneuver was part of the procedure. The postoperative course was complicated by ischemia, frequent ventricular extrasystoles, and periods of ventricular fibrillation. Left hemidiaphragmatic paresis necessitated later diaphragmatic plication. After an extended period of intensive care, she gradually recovered and finally was discharged from the hospital. Progressive dilatation of the aortic root with valvular insufficiency was observed during follow-up. Insufficiency was considered to be significant (2/4) when she was 1 year old. The left ventricle was dilated. Her condition deteriorated gradually, leading to fatigue on slight exertion. On physical examination at the age of 3 years 4 months, the girl weighed 12.5 kg. She had a murmur of aortic insufficiency at auscultation and a blood pressure of 105/45 mm Hg. The electrocardiogram demonstrated regular sinus rhythm with left ventricular hypertrophy and left precordial ST-segment inversions. The left ventricle had deteriorated according to the echocardiogram, with an end-diastolic dimension of 52 mm. The shortening fraction was calculated to be 25%. Aortic valve regurgitation was severe (4/4). The pulmonary valve was normal. Cardiac catheterization confirmed these findings. Pulmonary artery pressure was 25/10 mm Hg. Both coronary arteries were visualized angiographically and showed no evidence of stenoses. Angiography showed an aneurysm on the anterior aspect of the aortic root (Fig. 1. A and B). Fig. 1Angiograms showing the aneurysmal aortic root after the arterial switch procedure. A, Lateral angiogram: The aortic root has an aneurysmal anterior aspect and the left ventricle is dilated. B, Anteroposterior angiogram: Aneurysmal aortic root. AR, Aortic arch; AN, aneurysm; LV, left ventricle.View Large Image Figure ViewerDownload (PPT)Left ventricular contractions were diminished with diffuse hypokinesia. At operation, the anatomy was as expected after an arterial switch procedure, with the pulmonary artery in front of the aorta. The proximal part of the ascending aorta was aneurysmal. Cannulation was done high in the ascending aorta and in the right auricle with a right-angled cannula. Cardiopulmonary bypass with moderate hypothermia was started. A left vent was inserted and the aorta was crossclamped. St. Thomas' Hospital cardioplegic solution was infused every 30 minutes combined with external myocardial cooling. The pulmonary artery was transected just proximal to the bifurcation, which facilitated exposure of the aortic root. The pulmonary valve was tricuspid without signs of degeneration. The pericardium used to reconstruct the neopulmonary trunk had fused with the rest of the pulmonary artery. The aorta was transected just distal to the aneurysmal root. The aortic valve was tricuspid, with fibrosis and retraction of all three leaflets. The coronary buttons had grown after the switch procedure without evidence of coronary stenosis. The aortic valve and root were resected, leaving generous coronary buttons. Next the pulmonary trunk was dissected from the right ventricle. The external diameter was 18 mm and the aortic annular diameter was 1 mm larger. The autograft was used to reconstruct the resected aortic root. In an effort to prevent distention, we inserted the autograft slightly deeper into the left ventricle than the original aortic valve. The coronary buttons were inserted as U's after equal U-shaped parts had been excised from the pulmonary autograft to avoid widening of the intercommissural distances. All suture lines were sewn with running 5 or 6-0 Prolene sutures (Ethicon GbmH, Nordtstedt, Germany). After 100 minutes of myocardial arrest, the pulmonary trunk was reconstructed with a 21 mm cryopreserved pulmonary homograft (Heart Valve Bank, Berlin, Germany) on the beating heart. Cardiopulmonary bypass was discontinued after rewarming. After modified ultrafiltration, the cannulas were removed and protamine was given. Epicardial echocardiography showed a well-functioning new aortic valve with no or minimal insufficiency. Hemodynamics were good with dopamine 5 μg/kg per minute. She was extubated the next day and discharged from the intensive care unit on the second postoperative day. She was discharged from the hospital 9 days after the operation. Echocardiography showed a still dilated left ventricle and a well-functioning pulmonary autograft with a minimal central jet of insufficiency that was not considered to be of any hemodynamic importance. Aortic valve insufficiency is seen more frequently in patients after pulmonary artery banding previous to the arterial switch operation. Dilatation of the pulmonary trunk is the mechanism of insufficiency of the neoaortic valve after an arterial switch procedure. Even without previous pulmonary artery banding, aortic insufficiency seems to occur on occasion after the arterial switch procedure. The neoaortic valve diameter has been reported to be higher than in the normal population, which may explain the mild valvular regurgitation that is observed in some patients after the arterial switch procedure.2Klautz RIM Ottenkamp J Quaegebeur JM Buis-Liem TN Rohmer J. Anatomic correction for transposition of the great arteries: first follow-up (38 patients).Pediatr Cardiol. 1989; 10: 1-9Crossref PubMed Scopus (7) Google Scholar The exact pathogenesis of the increase in aortic anulus diameter in patients who have undergone the arterial switch is not fully understood. Surgical technical aspects may play a role. An increased intercommissural distance should theoretically lead to a loss of central coaptation of the valve cusps. Yamaguchi and associates3Yamaguchi M Hosokawa Y Imai Y Kurosawa H Yasui H Yagihari T et al.Early and midterm results of the arterial switch operation for transposition of the great arteries in Japan.J Thorac Cardiovasc Surg. 1990; 100: 261-269PubMed Google Scholar indicated that the use of coronary buttons may reduce the prevalence of insufficiency as compared with the use of trapdoor incisions and U-shaped coronary transfers.3Yamaguchi M Hosokawa Y Imai Y Kurosawa H Yasui H Yagihari T et al.Early and midterm results of the arterial switch operation for transposition of the great arteries in Japan.J Thorac Cardiovasc Surg. 1990; 100: 261-269PubMed Google Scholar In the patient we described, the aortic root aneurysm was the main cause of aortic insufficiency, although the thickening and retraction of the leaflets remain unexplained. A too wide pericardial patch may have been used at the time of the arterial switch operation to adapt the wider neoaortic root to the smaller distal ascending aorta (Fig. 1. A and B). Aortic valve replacement by mechanical valve prostheses after the arterial switch procedure for transposition has been performed (personal communication J. M. Quaegebeur, 1996) and reported earlier.4Ungerleider RM Gaynor JW Israel P Kanter RJ Armstrong BE. Report of neoaortic valve replacement in a ten-year-old girl after an arterial switch procedure for transposition.J Thorac Cardiovasc Surg. 1992; 104: 213-215PubMed Google Scholar Aortic valve repair after the arterial switch procedure has also been described.5Serraf A Roux D Lacour-Gayet F Touchot A Bruniaux J Sousa-Uva M et al.Reoperation after arterial switch operation for transposition of the great arteries.J Thorac Cardiovasc Surg. 1995; 110: 892-899Abstract Full Text PDF PubMed Scopus (72) Google Scholar In this infant we chose to replace the aortic valve with a pulmonary autograft for several reasons. Besides the known advantages of using a pulmonary autograft rather than other valve prostheses in children, some specific reasons were present in this special situation. Resection of the aneurysmal aortic root was necessary and the relatively difficult access to the aortic root made the choice of a homograft less preferable in view of the inevitable reoperation. The operation turned out to be straightforward. The anterior placement of the pulmonary trunk made its harvesting easy. Coronary artery problems were not encountered. Transposition may, however, be combined with coronary artery patterns that make harvesting of the pulmonary trunk more difficult, especially a right coronary artery crossing the right ventricular outflow tract. No important mismatch between the diameters of the pulmonary trunk and aortic anulus existed, which further encouraged us to choose the pulmonary autograft for aortic root replacement. In conclusion, the Ross procedure is technically feasible after an arterial switch operation and may be a particularly attractive alternative for this special population. This may be even more true because it is the original aortic valve that is used to replace the insufficient neoaortic valve.