Early and mid-term outcome of frozen elephant trunk using spinal cord protective perfusion strategy for acute type A aortic dissection

Abstract

Objective: This study aimed to evaluate the prevalence of spinal cord injury in total arch replacement with frozen elephant trunk for acute type A aortic dissection using our spinal cord protection technique.

Methods: Between January 2013 and December 2017, 33 patients underwent total arch replacement with frozen elephant trunk for acute type A aortic dissection (mean age 67.9 ± 13.3 years). Our spinal cord protection technique involved maintaining extracorporeal circulation through the left subclavian artery in all procedures, using aortic occlusion balloon during distal anastomosis, and inserting frozen elephant trunk above Th 8 with transesophageal echocardiographic guidance. Computed tomography was performed within 1-2 weeks, 12 months, and 36 months postoperatively. We compared the degree of thrombosis of the descending aorta between preoperation and early postoperative period by Fisher's exact test. Moreover, we evaluated postoperative mortality and mobility (including spinal cord injury) at follow-up.

Results: The operative mortality within 30 days was 6.1%. Neither paraplegia nor paraparesis was noted. We observed significant thrombosis of the false lumen at the distal arch and aortic valve level of the descending aorta in postoperative early term period (p < 0.01). At mid-term follow-up (mean 33.9 months), survival probability and 3-year freedom from reoperation rates were 93.9 ± 4.1% and 95.0 ± 4.9%, respectively.

Conclusions: The frozen elephant trunk technique with our spinal protection strategy provides good postoperative outcomes. Our strategy can maintain spinal cord perfusion without complete ischemia time even during lower body ischemia time. Implementation of our spinal protection strategy will help prevent spinal cord injury and dilated downstream aorta.

Keywords: Acute aortic dissection; Aortic balloon occlusion; Frozen elephant trunk; Spinal cord injury; Total arch replacement.

Fig. 1

Extracorporeal circulation during TAR-FET. a Two arterial perfusion cannulas are inserted into the left subclavian and unilateral femoral arteries and anastomosed to a 9-mm synthetic graft. A two-stage venous cannula is inserted through the right atrium, and a left ventricular vent tube is inserted through the right upper pulmonary vein. b When the urinary bladder temperature decreases to 28 °C, the left subclavian artery is ligated and the perfusion pressure of the left subclavian artery is maintained at to average of 60 mmHg under lower body circulatory arrest. After the aortic arch is incised, the balloon catheter is inserted into the brachiocephalic and left carotid arteries, and selective cerebral perfusion is established. The FET is deployed under transesophageal echocardiographic guidance. c After the FET is inserted, an occlusion balloon is inserted into it, and the lower body circulation is restarted from the femoral artery. The total perfusion flow rate is 2.4 L/min/m². d After distal anastomosis, antegrade perfusion is restarted and proximal anastomosis is performed. TAR-FET total arch replacement with frozen elephant trunk, LSA left subclavian artery

Fig. 2

Postoperative computed tomography imaging in total arch replacement with frozen elephant trunk using our strategy

Fig. 3

Aortic balloon technique for prevention of spinal cord injury. a After a frozen elephant trunk is inserted into the descending aorta, we insert an aortic occlusion balloon (yellow arrow). b The aortic occlusion balloon (blue arrow) is inflated, and lower body circulation is immediately restarted. With regard to the distal aortic stump, the proximal segment of the synthetic stent graft is wrapped from the inside to the outside and continuous suturing is performed with 4-0 polypropylene

Fig. 4

Kaplan–Meier estimate of survival probability and freedom from reoperation on the downstream aorta in TAR-FET. a Survival probability in the TAR-FET. b Freedom from reoperation on the dilated downstream aorta in the TAR-FET. TAR-FET total arch replacement with frozen elephant trunk

Fig. 5

Changes in the patency of the false lumen in the downstream aorta at the distal arch, aortic valve, and celiac artery levels. The number of patients with patent false lumens at the distal arch and the aortic valve level is significantly decreased in the TAR-FET group (p < 0.01) by Fisher’s exact test. At the celiac artery level, no significant change is observed. TAR-FET total arch replacement with frozen elephant trunk

Fig. 6

Changes in downstream aortic diameter at the aortic value and celiac artery levels from preoperation levels to 36 months postoperation. At the aortic valve level, the aortic diameter is not more dilated in the TAR-FET. At the celiac artery level, the aortic diameter gradually increases. TAR-FET total arch replacement with frozen elephant trunk