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How I Do It: Single Ventricle Palliation with Norwood/Sano, Bidirectional Glenn, and Extracardiac Fontan
O'Donnell A, Tweddell J. How I Do It: Single Ventricle Palliation with Norwood/Sano, Bidirectional Glenn, and Extracardiac Fontan. April 2023. doi:10.25373/ctsnet.22709626
The following videos are a posthumous tribute to Dr. James Tweddell to demonstrate and share his innumerable contributions to the field of congenital heart surgery. This video is part of a larger effort to accurately illustrate how Dr. Tweddell fine-tuned his single-ventricle palliative procedures, amongst others.
Stage I Palliation (SIP): Norwood with Sano (Right-Ventricle-to-Pulmonary-Artery Conduit)
First, a median sternotomy was performed. Antibiotic-soaked sponges were placed between the sternal plates and sternal retractor. A subtotal thymectomy was then performed. The right lobe was excised and the left lobe preserved, which is only done if feasible. The pericardium was divided and suspended. The innominate vein was then encircled and controlled with umbilical tape. The vein was retracted for dissection of brachiocephalic vessels, and the ascending aorta was separated from the pulmonary artery. The aortic arch, brachiocephalic vessels, and pulmonary arteries were then circumferentially dissected. All vessels were encircled loosely with fine silk tie. The right common carotid and right subclavian arteries were test-snared while monitoring the near infrared spectrometer (NIRS) and arterial line. The right common carotid (RCCA) and right subclavian arteries (RSCA) snares were then affixed to drape.
Next, the innominate artery was isolated for shunt anastomosis by lowering snares on the RCCA and RSCA and placing a Cooley carotid artery clamp on the base of the innominate artery. 100 U/kg of heparin was administered. The shunt acts as the arterial limb of the cardiopulmonary bypass (CPB) circuit. A longitudinal arteriotomy was then made along the isolated vessel. Retraction sutures were placed along the edges of the incision. A 3.5 mm graft of expanded polytetrafluoroethylene (ePTFE - Gore-Tex) was then selected. The graft was beveled with blue markings along the anterior surface. A small cut was made along the inferior edge of the bevel creating a “cobra head,” or widely patent, type of connection. Anastomosis was then completed with continuous 8-0 Prolene sutures. Following the anastomosis, the snares and clamp were all released individually to ensure vessel patency. Residual peri-shunt bleeding was addressed prior to CPB.
A full dose of heparin was then administered (400 U/Kg). Purse-string sutures were placed in the right atrial appendage for the venous cannula and the right atrial free wall for a ventricular vent. The shunt was cannulated with an 8 Fr arterial cannula and secured with silk ties. The right atrial appendage was cannulated with a 14 Fr right-angle cannula. A CO2 line was brought onto the field and secured to the diaphragm with a silk suture. The CO2 line was left in place and on until the patient was separated from CPB. The ductal snare was then lowered. Full flow CPB was then reached. The distal aortic arch was mobilized via blunt dissection. Next, patient cooling began. The patient was cooled for more than 30 minutes or until a bladder temp of less than 20 C was reached. The left common carotid (LCCA) and left subclavian arteries (LSCA) were further dissected and loosely encircled with fine silk snares. Snares were lowered on the branch pulmonary arteries (PAs) and the vent was placed through the right atrial free wall purse string.
A cryopreserved patch of thick pulmonary homograft was thawed prior to bypass. This patch was used to fashion two patches. The first was a 3 cm by 3 cm half-circle patch for the anterior patch aortoplasty. The second was a small circular patch which would be used to patch the branch PA confluence.
The main pulmonary artery was transected proximal to the bifurcation of the branch PAs. Traction sutures were placed in the anterior pulmonary artery root and anterior surface of the branch PA confluence. The branch PA confluence was closed, utilizing the small circular pulmonary homograft patch. The patch was then secured to the confluence with a continuous 7-0 Prolene sutures. Following the anastomosis, the ductal snare was released briefly to pressure test the patch and identify any sites that required suture repair. These sites were repaired as needed with simple interrupted 7-0 Prolene sutures. The ductal snare was then relowered.
Cardioplegia was administered. (Note: In patients with aortic atresia, antegrade cardioplegia can then be administered via the arterial cannula, while in patients with aortic stenosis, the cardioplegia can be delivered to the aortic root via direct cannulation.) The arterial limb was clamped distal to the stopcock, deaired, and connected to the cardioplegia line. The ascending aorta was then isolated by lowering snares on the LSCA, LCCA, RCCA, RSCA, and ductus. The descending thoracic aorta was occluded with forceps. Cold antegrade cardioplegia was then delivered to the coronary arteries.
Following cooling for more than 30 minutes or a bladder temp of less than 20 C, a short period of deep hypothermic circulatory arrest (DHCA) was achieved. The CPB pump was turned off and the venous cannula was removed. The right atrial appendage cannulation site was used to identify pulmonary veins and the atrial septum. Once identified, the atrial septum was excised. If the cannulation site is not feasible for excision, a separate small incision can be made along the right atrial free wall.
The right atrial venous cannula was then replaced, and the ductus was ligated and divided. The ductal ligature was left on branch PA side and was used for retraction. The descending thoracic aorta (DAo) was mobilized extensively with electrocautery and blunt dissection. The first three sets of intercostal arteries were divided with bipolar electrocautery. A Castañeda clamp was placed on the descending thoracic aorta distal to divided intercostals. The clamp was secured in place with a Kelly clamp off the left side of the sternal retractor.
Antegrade cerebral perfusion was then initiated. A curved Yasargil clip was placed at the origin of the innominate artery. Snares were released on the RCCA and RSCA.
The pulmonary artery confluence was then moved to the right side of aorta. This was achieved by pulling the ductal ligature under the aorta.
Neoaorta Construction—Part I
A coarctectomy was performed by the excision of all residual ductal tissue. The isthmus was then divided immediately distal to the origin of the LSCA. The DAo was divided 2–3 mm from the first set of divided intercostal arteries. A complete coarctectomy was performed to minimize the chance of obstruction or recoarctation.
The underside of the aortic arch was incised beginning at the opening where the isthmus was divided. The incision was carried out to the ascending aorta. This area was where the incision transitions from the underside of the arch to the medial surface of the ascending aorta and extended proximally to the “kissing point,” or 2-3 mm cephalad to the pulmonary root. Retraction sutures were placed along the aortic arch at the origin of the LSCA and the transition zone between the ascending aorta and aortic arch.
A cutback was then made in the posterior left lateral surface of the DAo. The cutbacks and interdigitation of the aorta help reduce the chance of obstruction by creating tissue redundancy. The posterior edge of the distal aortic arch was then interdigitated into the cutback of the DAo. The posterior edges of the open aortic arch and ascending aorta were sewn along the medial edge of the DAo. The lateral edge of the open aortic arch was then sewn along the lateral edge of the DAo. This was completed with a continuous 7-0 Prolene sutures.
Retraction sutures were placed cephalad to the right/posterior commissure and 2–3 mm toward the posterior sinus. A cutback was made on the pulmonary root just leftward of the right/posterior commissure. The anastomosis was completed between the pulmonary root cutback and ascending aorta with a continuous 8-0 Prolene sutures. DKS patency was confirmed with a 2 mm coronary probe. This ensures that DKS anastomosis has not stretched or obstructed native aortic root.
Neo-Aorta Construction—Part II
The final cutback was then made on the distal neoaorta on the anterior surface of the native DAo. The neo-aorta construction is completed by patching the anterior neo-aorta. This is completed with a continuous 7-0 Prolene sutures.
The top corner of the patch, where the curved edge meets the flat edge with the curved edge facing to the right of the patient, was sewn into the area of tissue triangulation, where the DAo and native aortic arch meet. Alternatively, if the native ascending aorta is longer, then the corner of the patch can be sewn into the cutback in the DAo.
The flat edge of the patch was sewn along the left lateral edge of the neoaorta to the pulmonary root—to the cephalad edge of the DKS.
Next, the curved edge of the patch was sewn along the native aortic arch and down the ascending aorta to the pulmonary root—to the cephalad edge of the DKS opposite the flat edge of the patch.
Finally, the inferior edge of the patch was sewn along the edge of the pulmonary root after being trimmed. Prior to completion of the anastomosis, the neoaorta was deaired with a directional syringe.
Sano (Right-Ventricle-to-Pulmonary-Artery Conduit) Placement
The Sano shunt was placed via the “dunk” technique. Prior to neoaorta construction, a right angle clamp was placed through the pulmonary root, marking the site on the right ventricle free wall. The wall was marked with electrocautery.
A stab incision was made at the marked site and dilated with hemostat. No muscle resection was necessary. A 5 mm graft of ring-reinforced ePTFE (Gore-Tex) was selected. The graft was cut to 5 cm in length and trimmed precisely later in the operation. The conduit was marked cephalad to the third ring to ensure a flush connection with the endocardium upon insertion. The proximal conduit was then “dunked” into the incision on the free wall of the right ventricle. Two purse-string sutures of 6-0 Prolene were placed around the perimeter and tied. Surgical adhesive was also placed around the connection perimeter.
Next, an ellipse of the branch PA confluence patch was excised for the distal anastomosis. The graft was controlled with a titanium clip placed across the middle of the conduit. The DAo clamp and Yasargil clamp, which were placed on the innominate artery, were removed. Full-flow cardiopulmonary bypass was then resumed. The patient was rewarmed entirely during the distal anastomosis. The graft was trimmed to the appropriate length to make the connection to the confluence on the right side of the neoaorta. The distal anastomosis was completed with a continuous 7-0 Prolene sutures. Prior to completion of the anastomosis, the branch PA snares were loosened to deair the connection.
All silk ties were then removed from the previously snared vessels. The titanium clip was removed from the Sano conduit. A malleable vent was placed under the sternal retractor and in between the pericardium and neo-aorta. Any obvious surgical bleeding was identified and repaired on the neoaorta. The right ventricle vent and CO2 line were removed. Modified ultrafiltration was carried out. A postoperative epicardial, or transesophageal echocardiogram, was completed to evaluate systemic ventricular function, atrial communication, presence of residual neoaortic arch obstruction, and Sano shunt connection.
The patient was successfully weaned and separated from CPB.
Stage II Palliation (SIIP): Superior Cavopulmonary Anastomosis (Bidirectional Glenn)
A redo median sternotomy was performed, and the bilateral pleural spaces were opened widely. Antibiotic soaked sponges were placed between the sternal plates and sternal retractor. The residual thymus was excised and the Sano conduit was dissected circumferentially. The superior vena cava was mobilized circumferentially to the level of the innominate vein. The azygous vein was then identified. The vein was then ligated in continuity and divided.
The patient was placed on standard aortobicaval CPB. The SVC was cannulated with a 10 Fr right angle cannula at the SVC-Innominate Vein junction. Then, patient cooling to 32 C began. A vent was placed in the right atrial free wall. CO2 was infused onto the field throughout.
The Sano conduit was ligated in continuity with titanium clips and divided. Temporary pacemaker wire leads were then sewn onto the surface of the systemic ventricle. Ventricular fibrillation was induced for proximal Sano conduit excision. The proximal conduit was excised and the ventriculotomy site was closed with two pledget supported horizontal mattress sutures of 4-0 Prolene. The intracardiac vent was shut off prior to tying of the sutures to help deair the ventricle. The sutures were then tied and the ventriculotomy was oversewn with a dual layer continuous 5-0 Prolene sutures.
The heart was then defibrillated following closure of the ventriculotomy. An umbilical tape was placed around the superior vena cava, and purse-string ligature was placed around the SVC cephalad to the SVC-RA junction. The snare was lowered on the purse string while monitoring the EKG for any changes. A marking suture was placed on the anterior surface of the SVC cephalad to the ligature. The SVC was then divided cephalad to the SVC-RA junction ligature. The ligature was then tied and used as retraction.
Next, the branch PAs were mobilized circumferentially to the first order of branches. The neoaorta can be encircled with umbilical tape to aid in this dissection. Once dissection was complete, the branch PAs were occluded to isolate the site of the superior cavopulmonary anastomosis. The left pulmonary artery (LPA) was controlled with a Satinsky clamp. The right pulmonary artery (RPA) was controlled with a Cooley carotid clamp. The distal Sano conduit was excised. The conduit site defect was incised along the RPA.
The posterior wall of the SVC was anastomosed directly to the posterior wall of the branch PA defect. This was completed with a continuous 7-0 Prolene sutures. This was then tied at the medial edge of the incision then again on the lateral edge of the incision. The anterior surface of the SVC was incised vertically to enlarge the anastomosis. The superior cavopulmonary anastomosis was completed with an anterior patch arterioplasty. A patch of thick pulmonary homograft was used and secured with a continuous 7-0 Prolene sutures.
The branch PA clamps were removed and the anastomosis was deaired. The anastomosis was then completed.
Stage III Palliation (SIIIP): Total Cavopulmonary Anastomosis (Fontan Completion)
A redo median sternotomy was performed, and the bilateral pleural spaces are opened widely. Antibiotic soaked sponges were placed between the sternal plates and sternal retractor. The IVC was then circumferentially mobilized and the atrium was fully mobilized off from the pericardium. The Glenn circuit was dissected and the branch PAs were circumferentially dissected. The stented LPA was gently dissected away from the posterior neoaorta without distorting the stent. A simple interrupted marking suture was placed on underside of Glenn circuit.
Prior to CPB, a Hegar dilator was used to determine the size of the Fontan conduit that would be used. A conduit of ePTFE (Gore-Tex) was selected. A 2.5 cm diameter circle was etched into the medial side of the conduit near the distal end. This was completed with an 11 blade. A 4.0 mm fenestration was created in the center of the circle. The outer layer of the conduit was peeled away within the 2.5 cm circle. The outer layer was peeled away to reduce the risk of layer fragment embolization when fenestration was created.
The patient was then cannulated and placed on aortobicaval CPB. The neoaortic root vent was then placed. Next, the neoaortic cross clamp was placed and antegrade cardioplegia was delivered. A vent was placed in the right atrial free wall and the IVC was further mobilized. The ventricle was freed from the diaphragm. The IVC was detached with a generous cuff of right atrium. The ePTFE conduit was then brought onto the field and positioned with the fenestration facing medial. The conduit was then anastomosed in an end-to-end fashion with the IVC with a continuous 5-0 Prolene sutures.
The edge of the atriotomy, the former IVC insertion site, was then anastomosed to the border zone between the layers of graft, with the fenestration positioned in the center with a continuous 5-0 Prolene sutures.
The snare was then lowered on the SVC and the branch PAs were mobilized further. The RPA was mobilized to the first branches. The LPA was then mobilized beyond the stent away from the neoaorta. The LPA was controlled with a Satinsky clamp beyond the stent. The RPA was controlled with a Cooley carotid clamp. The underside of the bidirectional Glenn circuit was incised and extended onto the RPA. The incision was extended onto the LPA beyond the extent of the LPA stent. The endothelialized stent was not amenable to removal. The exposed wires were then bent away from the lumen of the vessel. The cephalad end of conduit was beveled to augment the LPA. A ronguer was used to guide the depth of bevel. The conduit was then anastomosed to the underside of the bidirectional Glenn. The length of the conduit bevel aids in LPA augmentation. This was completed with a continuous 5-0 Prolene suture.
Finally, the RPA and LPA clamps were removed from the branch PAs. The patient was rewarmed and the heart was deaired. The aortic cross-clamp was then removed.
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