Selective left subclavian ligation in total aortic arch replacement

Left Subclavian Artery Sacrifice in Acute Aortic Dissection Repair using the Frozen Elephant Trunk

OBJECTIVE

Surgery of acute aortic dissection using the frozen elephant trunk (FET) can be complicated when the origin of the left subclavian artery (LSA) is dissected and sacrifice by ligation is a viable option. However, the LSA is supposed to play a role in neuroprotection as a major collateral. We, therefore, analyzed our results of LSA sacrifice in this cohort.

METHODS

We identified a total of 84 patients from our prospectively collected database who underwent FET repair of acute aortic dissection between October 2009 and April 2018. LSA was sacrificed in 19 patients (22.6%). Results were analyzed and compared with regard to neurological outcomes.

RESULTS

New postoperative stroke was seen in two patients (2.4%) and spinal cord injury in three patients (3.6%) overall, none in the LSA-sacrifice group. We observed a temporary neurological deficit in five patients (6.0%) overall, none in the LSA-sacrifice group. None of the patients developed acute ischemia of the left arm. Only two patients (12.5%) came back for carotid-subclavian artery bypass due to exertion-induced weakness of the left arm 3 to 4 months after the initial surgery. In-hospital mortality was 15.5% overall, with no difference between groups.

CONCLUSION

LSA sacrifice was not associated with elevated postoperative risk of either central or spinal neurological injury. Thus, it can facilitate FET repair of acute aortic dissection in selected cases when the left subclavian origin cannot be preserved. Carotid-subclavian artery bypass became necessary in only a small fraction of these patients and can be performed as a second-stage procedure.

Use of On-Site Digital Subtraction Angiography for Left Subclavian Artery Management During Hybrid Aortic Arch Repair in DeBakey I Dissection

PURPOSE

A hybrid aortic repair using the frozen elephant trunk (FET) technique with an open distal anastomosis in zone 2 and debranching of the left subclavian artery (LSA) has been demonstrated to be favorable and safe. Although a transposition of the LSA reduces the risk of cerebellar or medullar ischemia, this may be challenging in difficult LSA anatomies.

CASE REPORT

We present the case of a 61-year old patient with DeBakey I aortic dissection, treated with FET in moderate hypothermic circulatory arrest (26°C) and selective cerebral perfusion using a Thoraflex-Hybrid (Vascutek Terumo) prosthesis anchored in zone 2, with overstenting of the LSA orifice and no additional LSA debranching. Sufficient perfusion of the LSA was proved intraoperatively using LSA backflow analysis during selective cerebral perfusion in combination with on-site digital subtraction angiography (ARTIS Pheno syngo software). No neurologic dysfunction or ischemia occurred in the postoperative course. An angiographic computed tomography revealed physiologic LSA perfusion, with subsequent thrombotic occlusion of the false lumen in the proximal descending aorta after 7 days.

CONCLUSION

Using an angiography-guided management in patients with complex DeBakey I dissection and difficult anatomy may simplify a proximalization of the distal anastomosis in zone 2 for FET, even without an additional LSA debranching.

Comparison of the conventional frozen elephant trunk implantation technique with a modified implantation technique in zone 1

OBJECTIVES

The aim of the study was to compare the conventional frozen elephant trunk implantation technique with a modified implantation technique with an aortic anastomosis in zone 1 and extra-anatomic revascularization of the left subclavian artery during reperfusion.

METHODS

Between May 2014 and March 2018, 40 patients (26 male; mean age 60.2 ± 11.2 years) underwent complete aortic arch replacement with the Thoraflex Hybrid prosthesis™ (Vascutek, Inchinnan, Scotland) at our institution. Seventeen patients underwent conventional arch replacement (group 1) and 23 patients the modified procedure (group 2). Indication for arch replacement included all types of acute and chronic diseases.

RESULTS

Cardiopulmonary bypass time (213.1 ± 53.5 vs 243.8 ± 67.0 min, P = 0.13) and aortic cross-clamp time (114.4 ± 40.7 vs 117.3 ± 56.6 min, P = 0.86) did not differ significantly between group 1 and 2. There was a trend towards a shorter circulatory arrest time (50.72 ± 9.6 vs 44.7 ± 15.5 min; P = 0.20) in group 2. Perioperative mortality was 10% (5.9% vs 13%; P = 0.62). Stroke occurred in 10% (5.9% vs 13%; P = 0.62) of patients. Spinal cord injury occurred in 7.5% of patients (11.8% vs 4.3% P = 0.57). Due to the a proximal aortic anastomosis, there was a significantly shorter coverage of the descending aorta with the prosthesis ending at vertebral level Th7.5 (6.75-8) in group 1 versus Th6.0 (5.0-6.0) in group 2 (P-value = 0.004).

CONCLUSIONS

Implantation of the frozen elephant trunk prosthesis in zone 1 allows for a more proximal aortic anastomosis that could make the procedure more feasible especially in patients with difficult anatomies or in an acute setting.

Pectoral Muscle Atrophy After Axillary Artery Cannulation for Aortic Arch Surgery

To investigate postoperative pectoral atrophy in 141 patients undergoing aortic arch surgery involving bilateral axillary artery cannulations with side grafts. The depth from the skin to the axillary artery surrounding the thoracoacromial artery (zone 1), and the thicknesses of pectoralis major (zone 2) and pectoralis minor (zone 3) were measured by computed tomography before surgery, at 1 and 6 months after surgery, and at the most recent follow-up assessment (PostT2) (mean = 41 months, range 11-75 months). Based on the median value (47.4 mm) of zone 1, the preoperative pectoral thickness was categorized into 2 groups: pectoral thickness >47.4 mm (thick group) and ≤47.4 mm (thin group). Mean changes in the pectoral thickness from baseline were evaluated using the longitudinal mixed-effects model. Forty-three of 110 patients underwent total arch replacements and extra-anatomical bypasses for left subclavian artery anastomoses. In 3 patients, axillary artery grafts became infected. There was no obvious harm associated with muscle wasting. Mean changes from baseline in zones 1, 2, and 3 showed significant declines at PostT2 (-13.40 ± 9.73 mm [P < 0.0001], -7.00 ± 5.23 mm [P < 0.0001], and -7.23 ± 6.42 mm [P < 0.0001], respectively). In the thick group, the progression of pectoral atrophy in zones 1 and 3 was significantly more than that of the thin group (P < 0.0001 for both zones). Postoperative pectoral atrophy progressed rapidly. The preoperative pectoral size might be of no use in the prevention of pectoral atrophy. Further investigation to prevent the pectoral atrophy is needed.

Management of the difficult left subclavian artery during aortic arch repair

Management of the left subclavian artery (SCA) during aortic arch surgery is associated with several challenges, including preserving distal perfusion, achieving hemostasis and preventing posterior circulation stroke and spinal cord injury. The most common challenge remains its deep position in the chest, often exacerbated by posterior and apical displacement from an arch aneurysm. We discuss several management options consisting of pre-, intra- and post-operative strategies and their respective advantages, disadvantages and clinical outcomes. A clinical algorithm is proposed to help guide decision-making in managing the difficult left SCA during aortic arch repair.

Bow Hunter syndrome elicited by vertebral arterial occlusion after total arch replacement

An 83-year-old man with arch aneurysm underwent total arch replacement with frozen elephant trunk and extra-anatomical left subclavian artery bypass. One year later, he felt dizziness associated with head rotation. The hypoplastic left vertebral artery was occluded by a thrombus extending from the left subclavian artery ligation site, and the dynamic stenosis of right vertebral artery by head rotation induced dizziness. He was diagnosed with Bow Hunter syndrome. Vertebral artery hypoplasia represents a possible cause of this rare complication. To the best of our knowledge, this is the first report describing Bow Hunter syndrome after total arch replacement.

Elephant trunk technique for hybrid aortic arch repair

The original elephant trunk technique was developed by Borst in 1983 for the treatment of aortic arch aneurysms. This technique reduced operative risks, but was associated with cumulative mortality rates of 6.9 % for the first stage and 7.5 % for the second stage. Patients also waited a long time between two major surgical procedures. Only 50.4 % of patients underwent the second-stage surgery, and there was a significant interval mortality rate of 10.7 %. With the advent of stent-graft techniques, two different hybrid elephant trunk techniques were developed. One technique is first-stage elephant trunk graft placement followed by second-stage endovascular completion. The conventional elephant trunk graft provides a good landing zone for the stent-graft, and endovascular completion is a useful alternative to conventional second-stage surgery. This method has few major complications, and a postoperative paraplegia rate of 1.1 %. The other technique is the frozen elephant trunk technique. This technique eliminates the need for subsequent endovascular completion, and is particularly useful for the treatment of acute type A dissection because it can achieve a secure seal. However, it is associated with a higher rate of spinal cord ischemia than other methods such as the original elephant trunk technique. The left subclavian artery (LSA) is often lost when performing a hybrid elephant trunk procedure. Revascularization of the LSA should be performed to prevent arm ischemia and neurological complications such as paraplegia or stroke, although the level of evidence for this recommendation is low.