Surgical technique
All operations were performed under general anesthesia and through median sternotomy. Patients were monitorized with transesophageal echocardiography, bilateral cerebral saturation with near infrared spectroscopy and three arterial lines (both radial arteries and one femoral artery). We did not use cerebrospinal fluid (CSF) drainage.
After systemic heparinization, a pigtail catheter was placed in the descending aorta under transesophageal echocardiography control and through a 6F sheath in the femoral artery.
Arterial cannulation was performed directly or with an 8mm dacron graft interposition to the target artery. According to the anatomy and pathology, axillary, innominate or carotid arteries were used in order to obtain antegrade flow in the thoracic aorta and to facilitate the brain protection during circulatory arrest. In high-risk reoperated patients, cardiopulmonary bypass (CPB) was started before performing the sternotomy.
The operation was carried out under moderate hypothermia (20ºC-28ºC). Blood cardioplegia or crystalloid Bretschneider´s solution (Custodiol, Dr. Franz Köhler Chemie GmBH, Alsbach-Hänlein, Germany ) was delivered antegradely, retrogradely or combined. Once the heart was arrested, the aortic root or ascending aorta were repaired if needed. When the target temperature was achieved, circulatory arrest was instituted and antegrade selective cerebral perfusion was initiated. Aortic arch was resected, and distal aorta tailored to place the prosthesis.
The E-vita was placed antegradely. The prosthesis was inserted with a though-and-through wire technique with a 0.035” extra stiff guidewire, that was introduced retrogradely through the pigtail catheter. Although the landing zone depended upon the extension of the disease, we changed the distal anastomosis site to zone 2 or more proximally over time. Graft size was chosen according to the etiology: 10-20% oversizing in aneurysms and no oversizing in acute and chronic dissection.
Brain protection was achieved with unilateral or bilateral selective antegrade perfusion (SACP), and flow was adjusted to 10-15 mL/Kg/min and 50-60mmHg pressure. In order to improve the protection of the brain and spinal cord, we modified our technique to 1) perfuse the left subclavian artery (LSA) during lower body circulatory arrest and 2) early re- perfuse the thoracoabdominal aorta after the distal anastomosis was completed (Figure 2). LSA was dissected and ligated proximally during cooling. Its distal aspect was connected to the arterial line with an 8 mm dacron graft, which posteriorly, was anastomosed to the ascending aorta graft during rewarming. If supra-aortic arteries had to be re-implanted through a trifurcated graft, a femoral artery was also cannulated, and distal anastomosis were performed sequentially from the innominate artery to the LSA during cooling. The hybrid prosthesis was anastomosed to the distal remanent of the aorta with a double layer 3/0 polypropylene running suture and an external polytetrafluoroethylene felt.
Once the distal anastomosis was finished, a balloon catheter (Reliant, Medtronic, Mn, United States ) was inserted antegradely to occlude the stent graft. Then, the blood flow in the thoracoabdominal aorta was resumed through the femoral artery and rewarming was started. If femoral cannulation had not been performed because of peripheral vascular disease or extensive dissection affecting the femoral arteries, a Foley catheter was used to occlude the stent graft and to perfuse the distal aorta. Then, supra-aortic arteries were implanted to the vascular graft, using three different techniques depending on the anatomy and pathology: en-block , en-block (IA, LCA) and LSA bypass or through a self-made trifurcated graft. We systematically avoid clamping the arch graft, but rather maintain the balloon catheter into the stent graft until the arch graft is anastomosed to the ascending aorta with a 4/0 polypropylene running suture. In this way, it is easier to size the length of the arch prosthesis.