Two-Patch Repair Technique for Scimitar Syndrome via Vertical Right Axillary Thoracotomy
Scimitar syndrome is a rare congenital heart defect that occurs in one to three out of every hundred thousand births. Congenital pulmonary venolobar syndrome and vena cava bronchovascular syndrome are two of its many nomenclature. The defect was first described in an autopsy of an infant by George Cooper in 1836; however, the first diagnosis in an alive patient via cardiac catheterization is credited to Dotter et al. in 1949. Catherine Neill, the British pediatric cardiologist at Johns Hopkins, working alongside with Helen Taussig, described a familial form of this syndrome in 1960.
The key feature is the presence of the scimitar vein that resembles the curved Turkish sword, which drains the right lung into the inferior vena cava or to its junction with the right atrium.
This video shows a six-year-old, 27.9 kg boy who was diagnosed with scimitar syndrome. In this case, all right sided pulmonary veins drained into the inferior vena cava (IVC) and right atrial junction. The patient has no other significant surgical or medical history.
A chest X-ray showed enlargement of the right heart chambers with dextroposition of the heart. The scimitar vein could be seen to the right of the right heart border. An echocardiogram showed abnormal drainage and connection of the right sided pulmonary veins to the IVC and right atrial junction, but normal connection of the left-sided veins to the left atrium. The atrial septum was intact, and there was enlargement of the right atrial and right ventricular chambers with mild flattening of the interventricular septum.
A preoperative computed tomography scan (CTA) showed features of Scimitar syndrome with hypoplasia of the right lung and anomalous right pulmonary veins draining into the suprahepatic IVC.
The patient also underwent cardiac catheterization to show the scimitar vein and its course, in addition to multiple systemic arterial collaterals that supplied the right lung and cross the diaphragm. Because of the enlargement of the right cardiac chambers and the presence of a large shunt, the decision was made to proceed with surgical repair.
Surgical repair was performed via a vertical right axillary thoracotomy (VRAT). The patient was positioned in the modified left lateral decubitus position with his right side up.In addition to routine monitoring lines, an erector spinae block catheter was placed for postoperative pain management.
First, a vertical skin incision was made in the right midaxillary line extending from the second to the fifth ribs. Generous skin and subcutaneous flaps were created with electrocautery. Next, the anterior border of the latissimus dorsi muscle was mobilized and the fibers of the serratus anterior muscle were separated to expose the underlying intercostal spaces. Surgeons then entered the right chest through the right fourth intercostal space. Multiple pleural adhesions were discovered and dissected to expose the right lung, which was subsequently retracted to expose the pericardium. The pericardium was longitudinally opened 2 cm anterior to the right phrenic nerve, and stay sutures were placed.
Next, the interatrial groove was dissected. This is an important step as it helps in deciding whether the scimitar vein can be connected to the left atrium directly or has to be routed from inside the right atrium. The team then continued mobilization of the right lung and dividing the pleural adhesions. It is important to understand the location of the systemic collaterals that cross the diaphragm to the right lung. These collaterals usually travel through the inferior pulmonary ligament. Therefore, they must be identified properly, ligated, and divided. The right phrenic nerve can be adherent to the scimitar vein in this area; careful dissection of the scimitar vein must be done to avoid injuring the nerve.
After this, Heparin was administered systemically. The ascending aorta was cannulated with a 15 Fr arterial cannula. An 18 Fr right-angled metal tipped venous cannula was then placed in the superior vena cava (SVC). Once activated clotting time was satisfactory, cardiopulmonary bypass (CPB) was initiated without difficulty. A 20 Fr straight single stage venous cannula was placed in the IVC through its anteromedial wall to stay away from the entry site of the scimitar vein.
In some of these cases, surgeons will cannulatethe femoral vein and place the cannula low in the IVC to provide enough working space to suture the baffle without compromising the IVC ostium or risking leaving a residual shunt. Another option is to remove the IVC cannula during that part of the procedure, but the authors findthis unnecessary in the majority of cases.
Next in this case, the SVC was snared. An ascending aorta cardioplegia needle was then placed. The ascending aorta was cross-clamped, and cardioplegic arrest was achieved using antegrade cardioplegia. There was no need to snare the IVC.
An oblique right atriotomy was then made from the base of the right atrial appendage to the IVC cannula and was extended all the way to the diaphragm so it crossed the IVC and right atrial junction. Then, multiple stay sutures were placed.
It was clear that this vein was too far away from the left atrium to be implanted directly, and the surgeons did not want to risk kinking it, so it was decided to route the vein through the right atrium.
An atrial septal defect (ASD) was created, and the edges of the defect were endothelialized with running 5-0 Prolene sutures. An appropriately sized bovine pericardial patch was then used to create an intraatrial baffle, thus diverting the right-sided pulmonary venous return into the left atrium through the surgically created ASD. It was sewn in using running 5-0 Prolene sutures. The baffle started inside the IVC orifice around the entry site of the scimitar vein and continued up to the superior edge of the ASD.
A second patch of bovine pericardium was then used to augment the IVC and right atrial junction and a portion of the right atriotomy. It was sewn in using running 5-0 Prolene sutures. Halfway through the atriotomy closure, the heart was deaired and the aortic cross-clamp was removed. The patient regained his normal sinus rhythm. The rest of the right atriotomy closure was completed and the SVC snare was removed. The patient was then ventilated and weaned off CPB without difficulty.
A transesophageal echocardiogram showed widely patent intraatrial baffle with an unobstructed right sided pulmonary venous pathway and no intracardiac shunts. All cannulae were removed and the cannulations sites were secured. The rest of the procedure was then completed in the standard fashion.The aortic cross-clamp time was 73 minutes, and the CPB time was 107 minutes.
The patient was extubated in the operating room, received no transfusions, and the remaining postoperative course was uneventful. He was discharged on the second postoperative day and continued to do well during his follow-up.
A postoperative CTA showed widely patent intraatrial baffle connecting the scimitar vein to the left atrium and unobstructed IVC flow.
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