Abstract
A very rare case of a newborn with hypoplastic left heart syndrome and situs inversus totalis is herein reported. Successful surgical treatment of this cardiac malformation was accomplished at our institution and consisted of: modified Norwood stage I procedure, with direct anastomosis of the transected main pulmonary artery to the aortic arch, without any prosthetic material interposition and right ventricle to pulmonary artery polytetrafluoroethylene shunt.
1 Introduction
Situs inversus totalis is an extremely rare condition in which the disposition of all thoracic and abdominal organs is mirror image of normal. Its prevalence in the population is estimated about 1 in 10,000 [1]. Situs inversus is seldom associated with other malformations, thus possibly guaranteeing a normal life span. Nevertheless an increased incidence, up to 3% [1], of congenital cardiac malformations, has been clearly recognized in these patients. Hence situs inversus totalis has been reported so far in association with tetralogy of Fallot, ventricular septal defect [2], coronary artery anomalies [3], etc. To the best of our knowledge it has never been described before in association with hypoplastic left heart syndrome.
Hypoplastic left heart syndrome is a less rare malformation, which normally occurs in a {S,D,S} segmental arrangement (S, situs viscero-atrialis solitus; D, D-loop of the ventricles; S, solitus, normally related great arteries).
2 Case report
A 2.7kg full-term male product of an uncomplicated pregnancy presented at birth with cyanosis. The chest X-ray demonstrated the presence of situs inversus totalis of the thoracic and abdominal organs (Fig. 1).
An echocardiogram showed {I,L,I} (I, situs viscero-atrialis inversus; L, L-loop of the ventricles; I, normally related inverted great arteries) hypoplastic left heart syndrome with aortic and mitral atresia, and a persistent right superior vena cava draining into the coronary sinus.
Hemodynamic conditions were promptly stabilized and intravenous prostaglandin E1 infusion was started.
In the 8th day after birth he underwent modified Norwood stage I procedure. The operation was carried out on conventional cardiopulmonary by-pass with single atrial cannulation, through the left positioned right atrial appendage, and double arterial cannulation of main pulmonary artery and left innominate artery. Body temperature was lowered to 25°C and cardioplegic cardiac arrest was avoided, allowing coronary perfusion during the cross clamping phase.
Ductus arteriosus was doubly ligated and transected, pulmonary artery confluence was reconstructed with a bovine pericardial patch. After a generous dissection and mobilization of the aortic arch and epiaortic vessels, a direct anastomosis between the transected main pulmonary artery and the aortic arch was performed with a 7/0 PDS running suture. The aortic arch was previously prepared exciding all the ductal tissue and prolonging the incision through the coarctation site. The anastomosis was performed during selective antegrade cerebral and coronary perfusion with a 10–20ml/kg/min blood flow. Perfusion pressure, kept between 20 and 30mmHg, was monitored through a left brachial arterial catheter and continuous mixed venous blood saturation, maintained constantly around 60%, was also taken into consideration for adjusting blood flow.
After reperfusion of the reconstructed aortic arch, a 6mm polytetrafluoroethylene shunt was positioned between the anterior wall of the right ventricle and the confluence of the two pulmonary arteries.
The baby was easily weaned from the cardio-pulmonary by-pass with moderate doses of inotropic support, the sternum was closed and he was took to the post-operative intensive care unit where he spent 3 days without any major complication. The 2nd post-operative day he was weaned from the ventilator and the day after transferred to the ward were he spent a 10 day unremarkable recovery period.
The baby is now 5 months old doing well and waiting for a catheterization before bilateral bidirectional cavo-pulmonary anastomosis (Norwood stage II procedure).
3 Discussion
Hypoplastic left heart syndrome is a major cardiac malformation, which normally occurs in a {S,D,S} segmental arrangement. To the best of our knowledge this is the first case reported in literature of a patient with a {I,L,I} hypoplastic left heart syndrome (Fig. 2). Rarely, hypoplastic left heart syndrome may also occur in association with other cardiac malformations. It has been mainly reported in association with coronary anomalies, such as coronary ventricular fistulas, abnormal origin of the left coronary artery from the pulmonary trunk [4] or branches [5]; or in association with right aortic arch and left subclavian artery isolation [6], absence of aortic valve leaflets [7], etc. Some associated malformations reported, such as total anomalous systemic venous drainage to the coronary sinus [8] or cor triatriatum sinister [9], could be implicated in the pathogenesis of the underdevelopment of the left heart structures. Thus, the association itself could be more than just a coincidence, as Kadletz and colleagues stated [8] and than expected to be much more frequent than it is generally assumed. Other associated malformations, such as interrupted aortic arch [10], could be a consequence of the underdevelopment of the left heart structures or even they could be considered as part of the complex itself. We believe that the concomitance of HLHS and situs inversus totalis should be just a coincidental association and for this reason exceptionally rare.
Modified Norwood stage I operation was accomplished on the baby herein reported in an usual, even thought ‘mirror image’, fashion. The transected main pulmonary artery was connected to the right sided aortic arch concavity without prosthetic material employ and a 6mm polytetrafluoroethylene tube was interposed between the right ventricle and the confluence of the pulmonary arteries, letting the tube lie to the left of the aorta. Nor technical difficulties were encountered during the operation in regard to the situs inversus totalis, neither the outcome seemed to be influenced in any way by this peculiar situation.
In conclusion, this bizarre and unique association seems not to bear incremental technical difficulty during modified Norwood stage I procedure.
Chest X-ray: shows the complete ‘mirror image’ disposition of all thoracic and abdominal organs, consistent with situs inversus totalis.
Intraoperative view; surgical orientation. The photograph documents the anatomy of hypoplastic left heart syndrome in a complete reverse fashion, consistent with {I,L,I} segmental arrangement. Ao, aorta; PA, pulmonary artery; RA, right atrium; RAA, right atrial appendage; LAA, left atrial appendage.
