Technical option on tetralogy of Fallot with abnormal coronary artery

1. Chefe do Serviço de Cirurgia Cardíaca do Instituto Estadual de Cardiologia Aloysio de Castro do Rio de Janeiro. 2. Professor Doutor da Faculdade de Medicina da UFRJ. Professor da Escola de Medicina da Fundação Souza Marques do Rio de Janeiro. 3. Chefe do Serviço de Cardio Pediatria do Instituto Estadual de Cardiologia Aloysio de Castro do Rio de Janeiro. 4. Chefe do Pós Operatório de Cardio Pediatria do Instituto Estadual de Cardiologia Aloysio de Castro do Rio e Janeiro. 5. Professor Titular Emérito da Faculdade de Medicina da UFRJ. Cirurgião Cardiovascular do Instituto Estadual de Cardiologia Aloysio de Castro.


INTRODUCTION
A coronary artery with an abnormal pathway crossing the right ventricle outflow tract represents a challenge for the surgeons.This rare anomaly inspired the use of different techniques, which have been reported either in the reconstruction of the outlet chamber of the right ventricle (RV) (by graft or external conducts [1][2]) or in the correction by transatrial and transpulmonary surgical approach [3].In the two cases presented herein, we reproduced a technique that was successfully performed by van Son in 1995 [1] and by Dandolu et al in 1998 [4].
In this technique, we built two right ventricle outflow tracts.The first was composed of an external biological conduct (between the right ventricle and the pulmonary artery trunk on the coronary artery); the second maintained the original outflow tract of the pulmonary artery.Thus, these two outflow tracts compose a blood flow without any obstruction from the right ventricle to the pulmonary artery trunk.In this report, we describe the used surgical technique and the obtained outcomes.It is important to emphasize that this technical possibility may be one of the alternatives in the correction of Tetralogy of Fallot with abnormal coronary artery.

METHODS
Between 2001 and 2007, in the Aloysio de Castro State Institute of Cardiology in Rio de Janeiro, 568 children underwent heart surgery for treatment of congenital heart disease.In this group of patients, 55 presented Tetralogy of Fallot, from which 53 have been corrected using the transventricular approach after closing the interventricular septum defect with the transatrial approach.In two children who presented abnormal coronary artery crossing the RVOT, we used the technical option, which will be described in the report of these two cases.
This study was approved by the Research Ethics Committee of the Aloysio de Castro State Institute of Cardiology under the number 2008/16 of 03/05/2008.CASE REPORT 1 11-year-old boy was referred to the Cardiopediatric Department with diagnosis of Tetralogy of Fallot.The patient presented cyanosis from the first days of life and fatigue after moderate and slight efforts.During the clinical examination, he was extremely cyanotic; dyspnea at rest, with reduced height and weight for his age, as well as digital clubbing.During auscultation an ejective murmur in left sternal margin was audible, ++++/ 6. Chest radiography showed an increase of the right cavities.The hematocrit at the time of admission at hospital was 75% with the need for a transfusion.Preoperative echocardiography: wide interventricular septal defect.Presence of abnormal coronary artery.The cardiac catheterization showed subvalve stenosis and pulmonary ring with fair diameter.There was a single coronary artery trunk with anterior interventricular coronary artery crossing the right ventricle outflow tract.The patient underwent surgery on 02/27/02.

Surgical technique
After transsternal median thoracotomy and longitudinal pericardiotomy, an increase of the right cavities was found.The coronary arteries and veins were dilated and there was large epicardial collateral circulation.Important coronary branch crossed the right ventricle outflow tract.The ring and trunk of the pulmonary artery had appropriate dimensions.Isolation of ascending aorta.Purse suturing in the ascending aorta, superior vena cava, right atrium (near the inferior cava) and right superior pulmonary vein for drainage of the left ventricle.Systemic heparinization with 400 U/kg of pharmacological agent and initiation of cardiopulmonary bypass.Venous drainage of two cavas and left cavities through the right superior pulmonary vein with placement of the catheter tip in the left ventricle.Arterial return performed through the ascending aorta.
Once a temperature of 32º Celsius reached, the aorta was occluded with special forceps.Hypothermic blood cardioplegic solution was infused in the ascending aorta over 3 minutes and repeated at every 20 minutes of anoxic arrest.During cardiac arrest, a longitudinal opening of the right atrium was performed.There was small foramen ovale, which was closed with a x-stitche, 4-0 monofilament.Through the tricuspid valve a large defect in the interventricular septum was noted, (with two centimeters in the largest axis).The defect was closed with a heterologous bovine pericardium graft with one part attached with interrupted U sutures anchored in Teflon tablets, and other part attached with continuous suture 4-0 monofilament.Right atrium closing with double suture 4-0 monofilament.Incision of two centimeters in the right ventricular infundibulum, perpendicular and caudal to the coronary branch with the abnormal pathway.
There was severe hypertrophy of the parietal and septal extensions of the septomarginal trabeculae, covered by fibrous tissue, which created the "infundibuli" with at maximum 0,6cm diameter that was partially ressected.The pulmonary valve was slightly thickened, but without stenosis.The valvar ring presented compatible dimensions allowing the access of Hegar's dilator of 14mm.The anterior wall of the pulmonary artery trunk was longitudinally sectioned as a flap and reversaly sutured on the abnormal coronary in the upper extremity of the RV incision.
In order to fill the anterior wall of this new conduct, a patch of bovine pericardium was sutured in a tile shape on the edges of the pulmonary artery trunk and the remainder of the ventricle incision (Figure 1).The occlusion forceps of the aorta was removed after the patient was warmed, and after the careful removal of the air inside the left cavities.The heart spontaneously started to beat again, initially separated, and then reached sinus rhythm.CPB suspension at 37º Celsius.Volemic replacement based on right atrium pressure.Hemostasis review.Temporary pacemaker wire was installed in the RV wall.Drainage of the mediastinum and closing of the chest by planes.

Moderate pulmonary stenosis and;
Right ventricle with two outflow tracts.

CASE REPORT 2
An 18-month-old girl was admitted for cardiopediatric follow-up and correction of Tetralogy of Fallot.Her mother reported that, since the first month of life, the patient presented cyanotic mucous, and at six months began to present cyanotic crisis.The patient was then treated with beta blocker.The mother also reported neurological follow-up of the patient and an implant of a ventriculoperitoneal valve for the treatment of hydrocephaly.During clinical examination, the patient presented moderate cyanosis, without dyspnea, palpable and symmetrical pulses, without edema.ECG: RV hypertrophy.Cardiac auscultation with regular rhythm in two clicks, systolic murmur ++++/6 in left sternal margin.Ecocardiography: wide interventricular communication, anterior deviation of the infundibular-valvular pulmonary stenosis.The images suggested single coronary ostium.
The cardiac catheterization confirmed the diagnosis of Tetralogy of Fallot with a single coronary trunk.A branch of the right coronary artery gave origin of an important coronary artery branch, crossing the RV anterior wall.Hypertrophic right ventricle with good function, wide interventricular septal defect with dextroposition of the aorta above 50%.Undergone surgical correction on 29/10/03.

Surgical technique
Aside from the need for pulmonary commissurotomy to treat valve stenosis, and the 1,5cm incision in the RV wall, the technical procedure was similar to that which was previously reported in case 1.
The patient developed uneventfully in the immediate postoperative, with slight right heart failure that improved with clinical treatment.Echocardiography was performed in the immediate postoperative period: two patent RV outflow tracts without significant pressure gradient, mild pulmonary regurgitation and good ventricular function.Absence of residual shunt.Hospital discharge without cardiovascular symptoms.

Evolution
After surgery, the child's cardiovascular development was uneventful until four years and two months of age, at which point she died due to neurological disease with hydrocephaly, which she already presented before correction of Tetralogy of Fallot.

DISCUSSION
The most common anatomical variation occurs when the anterior descending artery is directly originated from

Evolution
The patient developed uneventfully and was discharged from hospital asymptomatic.In November 2007, at 16 years old, the patient was well and without complaints.Transthoracic echocardiography was performed: LV: Normal function with EF of 80% RV: Normal function, with slight dilation and pulmonary ring of 1,87cm.
Moderate tricuspid and pulmonary insufficiency; the right coronary artery [5].Less often, the coronary artery is single, or the right coronary artery originates from the circumflex coronary artery [5].In another variation, the septal coronary arteries originate from the left and right coronary arteries [6].The alternative procedure reported in these two cases is similar to a technique that has been previously described [1,4].In this technique, the authors adjusted the procedure described by Barbero-Marcial et al.
for correction of truncus arteriosus types I and II [7], and they used it analogously for the surgical treatment of Tetralogy of Fallot with abnormal coronary artery [1].
Because the posterior pulmonary artery wall of the patient is used in making composed biological conduct (either made of bovine pericardium with cryopreserved pulmonary graft [4]), it is natural that the biological conduct presents a real potential for growth over the years.[1].This technique, in addition to the transannular patch, undoubtedly causes pulmonary failure [4].However, the pulmonary failure (which resulted from a valveless graft) may be avoided using a monocuspid valve on the anterior wall of the bovine pericardium graft [7]).And, to avoid early calcification, Croti and Barbero Marcial employ porcine monocuspid for surgical correction of pulmonary atresia with interventricular communication [8].On the other hand, residual stenosis may occur and must be subsequently treated [4].

CONCLUSION
The technique reported in this study proved to be safe and effective.We recommend it as another option to be employed in the correction of Tetralogy of Fallot with abnormal coronary artery that crosses the RVOT.

Fig. 1 -
Fig. 1 -Extracardiac conduct -Biological graft filled between the right ventricle and the pulmonary artery trunk upon the abnormal coronary.