Prevalence and management of coronary artery anomalies in tetralogy of Fallot at Cheikh Zaid Hospital’s Pediatric Cardiac Surgery Department in Morocco: retrospective study

Introduction Tetralogy of Fallot (TOF) is one of the most common cyanogenic congenital heart defects. It represents 10% of congenital heart diseases in children. Coronary artery anomalies (CAA) have been reported in 2% to 14% of cases in patients with TOF, according to angiographic, surgical and autopsy series. Many of these anomalies are difficult to detect during surgery. The objective of this article is to study the prevalence of the coronary artery anomalies in patients with TOF as well as their surgical management in our hospital between 2007 and 2015. Methods A retrospective study was conducted on 90 patients with TOF aged 1 month to 10 years who were operated on in the Department of Paediatric Cardiac Surgery of Cheikh Zaid Hospital between 2007 and 2015. None of the patients had preoperative coronary angiography and all the anomalies were diagnosed during surgery. Patient clinical data were collected from patient records and from the hospital information system. The qualitative variables are expressed as mean and standard deviation and the quantitative variables are expressed as a percentage. Statistical analyses were performed using SPSS 13.0 software. Results Of the 90 patients with TOF followed in the study period, 9 (10%) patients had coronary artery anomalies. We found in 3 (33%) patients an anomalous origin of the left anterior descending coronary artery (LAD) from the right coronary artery (RCA), an anomalous origin of the RCA from the left coronary trunk (LCT) in 1 (11%) patient and a large infundibular branch blocking the pulmonary infundibulum in 5 (56%) patients. All the patients underwent a complete surgical treatment (closure of the ventricular septal defect (VSD) by patch plus stenosis resection plus infundibular enlargement by patch). Eight (89%) patients progressed well in postoperative care and 1 (11%) died immediately after surgery in intensive care. Conclusion The coronary anomalies detected in patients with TOF are rare but represent a challenge for the surgical team because of the difficulty of diagnosing them pre-operatively. The management of these anomalies is mainly surgical and the technique used by our team is proved to be safe and effective.


Introduction
Tetralogy of Fallot is one of the most common cyanogenic congenital heart diseases. It represents 10% of congenital heart disease in children [1]. Coronary artery anomalies (CAA) have been reported in 2% to 14% of patients with TOF according to angiographic, surgical, and autopsy series [2]. Many of these anomalies are difficult to detect during surgery because coronary arteries may be obstructed by adhesions after previous palliative surgery or intramyocardial route and/or epicardial fat [3]. In the total correction of the TOF, the main objective is the ventricular septal defect (VSD) closure and the raising of the obstacle to the ejection of the right ventricle. However, an anomaly of the coronary artery that crosses the right ventricular ejection pathway represents a surgical challenge. Our objective in this work is to evaluate the prevalence of coronary artery anomalies in TOF in children under 10 years old and to present our experience in the surgical management of these anomalies.

Methods
The study was conducted at the Cheikh Zaid Hospital in Rabat, a hospital containing a paediatric cardiac surgery department that is considered as a reference centre for the management of congenital heart disease. It has a state-of-the-art operating room, a cardiac

Results
Of the 90 patients with TOF followed in the study period, 9 (10%) patients had coronary artery anomalies. Among these anomalies, we found in 3 (33%) patients an anomalous origin of the left anterior descending coronary artery (LAD) from the right coronary artery (RCA), an anomalous origin of the RCA from the left coronary trunk (LCT) in 1 (11%) patient, and a large infundibular branch blocking the pulmonary infundibulum in 5 (56%) patients. All patients underwent a complete surgical treatment (closure of the VSD by patch plus stenosis resection plus infundibular enlargement by patch).
Eight (89%) patients progressed well in postoperative care and 1 (11%) died immediately after surgery in intensive care. Patient characteristics are presented in the Table 1, Table 2, Table 3. reported that coronary artery anomalies (CAA) have been reported from 2% to 14% of patients with TOF according to angiographic series [4][5][6][7][8], surgical series [9][10][11][12], and autopsies [13,14]. The low incidence of coronary artery anomalies in TOF reported by surgical teams can be explained by the fact that many of these anomalies are difficult to detect intraoperatively [4,9,10,15,16]. In our series, the diagnosis of a coronary artery anomaly was made by the surgical team peroperatively because of the difficulty in detecting them by transthoracic echocardiography, which remains the only means of imaging used by our cardiologists. Surgically, all patients underwent total TOF repair by sternotomy and with a heart-lung bypass machine.

Discussion
Myocardial protection was provided by crystalloid cardioplegia administered at the root of the aorta and repeated every 15 minutes.
The total repair of a TOF consists of closure of the VSD by patch, a resection of the pulmonary stenosis by infundibular route, avoiding the coronary artery that crosses the pulmonary pathway.
Subsequently, the ejection pathway of the right ventricle is widened by arranging the anomalous coronary artery by patch. Any anomaly of the coronary artery crossing the right ventricle ejection pathway affects the type and timing of complete surgical repair in patients with TOF [17,18]. Any coronary anomaly that could interfere with right ventriculotomy or resection of the obstruction of the exit pathway should be identified preoperatively because sternotomy may not be the preferred approach for palliative care, and/or because the coronary arteries may be obstructed by adhesions after previous palliative surgery, or by an intramyocardial route [6].  [20,21].
However, the use of RV-PA conduit in patients with TOF and with coronary artery anomalies makes a second intervention unavoidable, since the ducts have no growth potential and therefore a relative stenosis of the right ventricle ejection pathway will occur [22]. In our series, we adopted the same surgical strategy in 8 cases, consisting of a resection of the pulmonary stenosis by infundibular route after right ventriculotomy while avoiding the coronary barring the right ventricular ejection pathway. In one case, we adopted the Rastelli technique with a RV-PA conduit. The choice of these strategies is  The prevalence of these anomalies is 10% which is consistent with the world literature;  Complete correction is the most appropriate technique to avoid palliative surgery. and AEH: participated in design of the study, reading and correcting paper. All authors read and approved the final manuscript.

Acknowledgments
The authors wish to thank all the individuals and institutions that made this study possible especially the hospital's cardiac surgery team.