An Investigation is Always Trending
We report here-in a 30 days-old male child diagnosed with D-transposition of the great arteries of the ventricular septal defect, Yacoub’s type A coronary arterial pattern undergoing anatomical correction at the arterial level with Dacron patch closure of the ventricular septal defect under moderately hypothermic cardiopulmonary bypass and St. Thomas (II) based cold blood cardioplegia. Postoperative recovery was uneventful at 2 months follow-up, the child is asymptomatic, on nil medications and in Ross clinical score of 2.
Surgical planning and the position
Following median sternotomy, the thymus was sub totally excised taking care not to expose the brachiocephalic vein. The pericardium was incised about 5-6 mm in front of and parallel to the phrenic nerve, thus exposing the two great arteries, the right atrium and the superior vena cava. The pericardium was opened using scissors and not cautery to avoid inadvertent cautery-induced ventricular fibrillation. A rectangular segment of pericardium was harvested and fixed in 10% glutaraldehyde for 10 minutes for later use of right ventricular outflow tract reconstruction.
The position and size of the great arteries, as well as the site of origin and distribution of the coronary arteries was determined. All four chambers were inspected and pressures recorded. Note the anteroposterior disposition of the aorta and the main pulmonary artery with the left main coronary artery arising from the left posterior aortic sinus and the right coronary artery arising from the right posterior aortic sinus. The left main coronary artery giving origin to the left anterior interventricular coronary artery and circumflex coronary artery.
The operation was performed with moderately hypothermic cardiopulmonary bypass at 32° C. Angled venous cannulas were inserted into the superior and inferior caval veins and with distal aortic cannulation. Measures were taken to avoid excessive manipulation.
Dissection and division of the ductus arteriosus
The persistent ductus arteriosus was dissected on the superior surface of the pulmonary artery by McGoon’s technique, transfixed at both aortic and pulmonary arterial ends using 6-0 polypropylene suture (Johnson and Johnson Ltd., Ethicon, LLC, San Lorenzo, USA) and was divided.
Mobilization of the aorta and the pulmonary arteries
The two great arteries were separated from each other by dividing the pericardial reflection and between them, starting from the level of the top of the commissures and pulmonary artery till the level of pulmonary arterial branching on either side. Low voltage cautery (10- 15 mv) was used during dissection. The aorta, right pulmonary artery and left pulmonary artery were looped using elastomer vessel loops.
Placement of marking sutures at the proposed neoaortic location of coronary transfer
Two marking sutures were placed over the pulmonary artery at the proposed neoaortic location. Note the site of neoaortic coronary button, little above the sinuses to avoid waisting/kinking of the coronaries.
Cross clamping of the ascending aorta and administration of cardioplegia
The aorta was cross-clamped. Antegrade St. Thomas based (1:4) cold blood cardioplegia and topical cooling was used for myocardial preservation.
Venting of the left ventricle
Right atriotomy was done after snugging the inferior caval vein and left heart was vented through the atrial septal defect using a No.13 DLP suction vent (Medtronic Inc., Medtronic Parkway N.E., Minneapolis, MN, USA).
Dacron patch closure of the ventricular septal defect
The ventricular septal defect is closed using an appropriately sized Dacron polyester patch (Bard® Savage® filamentous knitted polyester fabric, Bard Peripheral Vascular Inc., Tempe, AZ, USA) and pledgeted 5-0 polypropylene sutures (Johnson and Johnson Ltd., Ethicon, LLC, San Lorenzo, USA). The tricuspid valve is being checked for competence injecting cold saline through the tricuspid valve into the right ventricle.
Administration of second dose of cardioplegia
Second dose of antegrade root cardioplegia was administered after closing the ventricular septal defect.
Dissection of the aorta and pulmonary trunk
The aorta was divided in between stay sutures at the level of pulmonary arterial bifurcation. Two stay sutures of 6-0 polypropylene were placed on the top of each coronary buttons for retraction and mobilization. The transected distal aortic end was retracted superiorly for optimal visualization and uncluttering of surgical field. The pulmonary trunk was next divided about 1-2 mm below the level of pulmonary arterial bifurcation. The vessel loops on right and left pulmonary arteries were placed on traction for the LeCompte manoeuvre.
Inspection of the pulmonary valve
The pulmonary valve and sub pulmonary region were inspected through the transected end of the pulmonary artery.
Identification of the coronary artery
The position of the coronary ostia and their relation to the sinuses of valsalva of the aortic and pulmonary valves were determined. Note the origin of both coronary arteries from the left and right posterior sinuses respectively. Additionally, the course and mode of branching of the proximal 5-6mm of each artery was inspected.
Mobilization of coronary buttons
The left and right coronary ostia were mobilized with a surrounding rim of aortic wall including almost the full thickness wall of the sinus of valsalva without causing injury to the valve leaflets. The process was started at the edge of the transected aortic wall for the left coronary ostium followed by the right coronary ostium. Low voltage cautery (5-6 mv) was used for hemostasis at the harvested site.
Creation of medial-based pulmonary arterial flaps for coronary artery translocation
A site on the pulmonary artery for the left and right coronary anastomoses were chosen. This neoaortic location was higher than the top of the sinus of valsalva, to avoid tension/kinking/waisting of the coronary arteries and to avoid distortion of the aortic valve. Two medially based pulmonary arterial flaps as described by Roger Mee were created accordingly. The sites chosen allowed for rotation of the mobilized coronary buttons through an angle not more than 30°. No portion of the pulmonary arterial wall was excised.
The coronary anastomoses were performed using 6-0 polypropylene suture, taking care not to injure the coronary ostia and distortion of the mobilized disc
The LeCompte manoeuvre
The pulmonary arterial bifurcation, right and left pulmonary arteries were mobilized beyond the site of the divided ductus into the pulmonary hilum on the left side and behind the superior vena cava to the branching of the right pulmonary artery on the right side. The distal transected end of the aorta was then threaded behind the mobilized pulmonary arterial bifurcation by LeCompte manoeuvre and the second aortic controlling clamp was transferred onto the aorta at its new site behind the pulmonary artery bifurcation.
Reconstruction of the aorta
The small distal end of the aorta was matched to the larger proximal end for anastomosis using 6-0 polypropylene suture.
Repair of the defects in the aortic sinus
Two defects, which was produced in the facing sinuses of the pulmonary trunk, were repaired using a single patch of the autologous pericardium and 6-0 polypropylene suture. The size of the patch is approximately one and a half times the size of the defect, thus enlarging the diameter of the proximal aorta to match the size of the distal pulmonary artery. At this stage, we used topical thrombin (Tisseel, Baxter AG, Vienna, Austria) as an additional topical hemostatic agent.
Release of the aortic cross-clamp and restoration of myocardial perfusion
The aortic cross-clamp was released, thus restoring myocardial perfusion. Note the distended left and right coronary arteries perfusing the myocardium without any kinking or torsion.
Reconstruction of the pulmonary artery
The last stage of the LeCompte manoeuvre consists of direct anastomosis between the reconstructed proximal aorta and the distal pulmonary artery using a 6-0 polypropylene suture. Precautions were taken to anastomose the two ends without compressing the proximal parts of the coronary arteries, without causing narrowing of the right and left pulmonary ostia and without stretching the branches of both pulmonary arteries.
Closure of the right atriotomy
The atrial septal defect was directly closed using 5-0 polypropylene suture. The right atrium was closed in two layers using 5-0 polypropylene suture. The child was weaned-off cardiopulmonary bypass with stable hemodynamic on dobutamine and nitro-glycerine infusion.
We conclude that anatomical correction of transposition of the great arteries at the arterial level restores anatomical left ventricle to aortic continuity, thereby avoiding atrial arrhythmias, baffle obstruction and right ventricular failure, which occur following correction at the atrial level. Meticulous attention should be exercised at every step of the operation including coronary artery transfer to obtain a satisfactory outcome.