Application of the “Branch-First Technique” in Sun’s Procedure
The branch-first technique has emerged as a significant advancement in aortic arch surgery, particularly for patients with complex arch lesions. This technique ensures total cerebral perfusion during the operation, thereby reducing the risk of neurological complications. The procedure involves the use of a double “Y” or modified three-branch graft to reconstruct the aortic arch vessels. This article provides a comprehensive overview of the application of the branch-first technique in Sun’s procedure, detailing the surgical steps, technical innovations, and clinical outcomes.
Introduction to Sun’s Procedure and the Branch-First Technique
Sun’s procedure has revolutionized the surgical management of aortic dissections, penetrating ulcers, and aneurysms involving the aortic arch. The procedure involves total arch replacement using a tetrafurcate graft with stented elephant trunk implantation. This approach has significantly improved the feasibility and safety of aortic arch surgery. The branch-first technique, a variant of Sun’s procedure, was developed to further enhance cerebral perfusion and simplify the surgical process.
The branch-first technique originated from an improvement of Spielvogel’s approach to aortic arch surgery. Spielvogel was the first to reconstruct the aortic arch vessels using a three-branch graft under axillary artery cannulation. The surgery was performed under systemic cooling, with the reconstruction of the aortic arch vessels completed under circulatory arrest and selective cerebral perfusion. The order of vascular reconstruction was the left common carotid artery first, then the left subclavian artery, and finally the innominate artery.
In 2011, Matalanis et al. reported a series of cases that improved upon Spielvogel’s method. They simultaneously cannulated the femoral artery and the axillary artery, allowing the innominate artery to be cut-off and reconstructed first without affecting lower body perfusion. This modification changed the reconstruction order to the innominate artery first, followed by the left common carotid artery, and finally the left subclavian artery. A modified three-branch graft was used for the reconstruction, ensuring continuous bilateral cerebral perfusion.
Case Presentation
A 62-year-old man presented with a localized penetrating ulcer at the junction of the ascending aorta and the aortic arch. The patient was scheduled for replacement of the ascending aorta and the arch. Under general anesthesia, the right axillary artery and the right common femoral artery were mobilized. A median sternotomy was performed, and the three arch vessels were mobilized.
A “Y” shaped graft was constructed using a 16mm straight Dacron graft as the trunk and an 8mm straight Dacron graft as the side arm. The right axillary artery, right common femoral artery, and right atrium were cannulated to establish cardiopulmonary bypass (CPB). The CPB was initiated without lowering the temperature and with a beating heart. The average arterial blood pressure was maintained at approximately 80mmHg.
Surgical Steps
The innominate artery was clamped and transected 1cm distal to its origin. The stump of the innominate artery was closed by continuous suture. The distal end of the innominate artery was anastomosed with the distal end of the main trunk of the “Y” shaped graft. Next, the left common carotid artery was transected, and its stump was closed. A circular fenestration, matching the size of the left common carotid artery, was made in the side arm opposite the left common carotid artery. The distal end of the left common carotid artery was anastomosed to the side arm in an end-to-side fashion. The side arm was deaired, and its distal end was clamped. At this stage, both the innominate artery and the left common carotid artery were supplied by axillary artery perfusion.
The left subclavian artery was then transected, and its stump was closed. The distal end of the left subclavian artery was connected to the distal end of the side arm in an end-to-end fashion. At this point, all three arch vessels were bypassed with the “Y” shaped graft, ensuring total blood supply to the brain.
Hypothermic Circulatory Arrest and Aortic Replacement
The temperature was then cooled down. The ascending aorta was clamped and opened. Cardioplegia solution was perfused directly into the coronary orifices. A straight graft of 28mm was chosen to replace the ascending aorta. The proximal anastomosis site was at the sino-tubular junction, and continuous suture with 4-0 prolene was used. At 28°C, the flow was decreased to 10mL·kg⁻¹·min⁻¹. The cannula to the femoral artery was clamped. The arch was opened and transected between the innominate artery and the left common carotid artery. An open stent-graft (30×100mm) was deployed into the arch and descending aorta. Its proximal end, along with the native aortic wall, was anastomosed with the ascending aorta graft using a 3-0 prolene running suture. After the anastomosis was completed, systemic perfusion was resumed. Following deairing of the heart, the cross clamp was opened. A side bite clamp was applied to the ascending aorta graft, and a fenestration was made. The proximal end of the 16mm graft was then anastomosed to the ascending aorta graft in an end-to-side fashion.
Clinical Outcomes
The cross clamp time was 58 minutes, the CPB time was 107 minutes, and the circulatory arrest with total cerebral perfusion time was 13 minutes. The patient recovered well postoperatively, with no neurological complications. CT angiography performed six months after the surgery showed excellent results, with the graft trunk, graft side arm, and all three arch vessels functioning properly.
Discussion
The branch-first technique combined with Sun’s procedure offers several advantages. First, it ensures continuous cerebral perfusion throughout the surgery, significantly reducing the risk of neurological complications. Second, the use of a “Y” shaped graft simplifies the reconstruction process and saves space. Third, the technique allows for a higher core temperature (28°C) compared to traditional methods (23°C), reducing the risk of coagulopathy associated with deep hypothermia.
One of the challenges in Sun’s procedure is the mobilization of the left subclavian artery, particularly for less experienced surgeons. The branch-first technique addresses this issue by allowing the posterior wall of the aortic arch to be dissected from the surrounding tissue. This maneuver lifts and pulls the arch caudally, making the left subclavian artery easier to expose.
Conclusion
The branch-first technique is a feasible and effective approach in Sun’s procedure for aortic arch replacement. The use of a “Y” shaped graft ensures continuous cerebral perfusion, simplifies the surgical process, and reduces the risk of complications. This technique represents a significant advancement in the surgical management of complex aortic arch lesions, offering improved outcomes for patients.
doi.org/10.1097/CM9.0000000000000049
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