Repair of Partial Atrioventricular Septal Defect via Vertical Right Axillary Thoracotomy (VRAT) in Eleven-Year-Old
The patient is an eleven-year-old, 38.8 kg boy who was diagnosed with partial atrioventricular septal defect and has been followed clinically with minimal symptoms. Past medical and surgical history included ADHD and need for surgery for club feet. A chest X-ray showed cardiomegaly with increased pulmonary vascularity. A preoperative ECG showed sinus bradycardia with left axis deviation and a nonspecific intraventricular conduction delay.
Of note: this article will refer to the left and right atrioventricular valves as the mitral and the tricuspid valves, respectively, and will refer to the zone of apposition of the left atrioventricular valve as the cleft in the anterior mitral valve leaflet. This is for simplicity, as we know there are differences between these anatomic structures.
An echocardiogram showed a large ostium primum atrial septal defect with a large left-to-right shunt. The defect measured about 2 cm in diameter. There was a cleft in the anterior leaflet of the mitral valve with a mild to moderate degree of mitral valve regurgitation. The septal leaflet of the tricuspid valve appeared to be tethered with mild tricuspid valve regurgitation. There was no ventricular level shunt and no additional atrial level shunting. There was a moderate degree of right atrial and right ventricular chambers enlargement with normal systolic function. The decision was made to proceed with surgical repair via a vertical right axillary thoracotomy.
In this case, the patient was positioned in the modified left lateral decubitus position with the right side up. In addition to routine monitoring lines, an erector spinae block catheter was placed for postoperative pain management. A 6 cm vertical skin incision was made in the right midaxillary line extending from the second to the fifth ribs. Generous skin and subcutaneous flaps were then created with electrocautery. The anterior border of the latissimus dorsi muscle was slightly mobilized, and the fibers of the serratus anterior muscle were separated to expose the underlying intercostal spaces. The right chest was entered through the right fourth intercostal space, and the right lung was retracted to expose the pericardium.
Next, the pericardium was longitudinally opened 2 cm anterior to the right phrenic nerve, and stay sutures were placed. Heparin was then administered systemically. The ascending aorta was cannulated with an 18 French arterial cannula. The inferior and superior venae cavae were cannulated with a 22 French and 20 French right-angled metal-tipped venous cannula, respectively. Once the activated clotting time (ACT) was satisfactory, cardiopulmonary bypass was initiated without difficulty at normothermia, and both cavae were encircled with snares. An ascending aorta cardioplegia needle was then placed. The ascending aorta was cross-clamped and cardioplegic arrest was achieved in the standard fashion. Both cavae were then snared.
After this, an oblique right atriotomy was made from the base of the right atrial appendage to the direction of the inferior vena cava cannula. The intracardiac anatomy was as described. The cleft in the mitral was identified and closed with multiple interrupted 5-0 Prolene sutures that were placed in a simple fashion. The valve was then tested and appeared competent. An appropriately sized bovine pericardial patch was then used to close the ostium primum atrial septal defect. It was sewn in using running 5-0 Prolene sutures. In the area of the coronary sinus, the suture line was deviated to the left atrial side of the interatrial septum to avoid the conduction tissue, thus leaving the coronary sinus draining on the right atrial side. The suture line was then transitioned back to the margin of the defect once the coronary sinus was passed. The Valsalva maneuver was then performed to rule out any residual shunts and de-air the left side of the heart.
Next, a limited suture annuloplasty was performed for the dilated tricuspid annulus to improve the valve leaflets coaptation, and was tied over a Hegar dilator. The heart was de-aired and the aortic cross-clamp removed. The patient regained his normal sinus rhythm.
The right atriotomy was then closed using running two-layer 5-0 Prolene sutures, and the caval snares were removed, followed by weaning off cardiopulmonary bypass in the standard fashion. A postbypass transesophageal echocardiogram showed normal biventricular function with no residual shunts and trivial-to-mild mitral and tricuspid valve regurgitation.
Finally, all cannulae were removed and cannulation sites were secured. Protamine was given and hemostasis was achieved. The pericardium was then closed with interrupted Prolene sutures, leaving multiple windows in between for drainage. One 24 French channeled drain was placed and its tip directed toward the cardiac apex. The incision was then closed in the standard fashion. The aortic cross-clamp time was seventy-five minutes, and the cardiopulmonary bypass time was ninety-nine minutes.
The patient was extubated in the operating room and received no transfusion. The remaining post-operative course was uneventful. He was discharged on the second post operative day and continued to do well during his follow-up. Follow-up transthoracic echocardiogram showed no residual atrial level shunt. It showed trivial to mild mitral and tricuspid valves regurgitation with normal biventricular function.
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