Left Subclavian Artery Revascularization During Frozen Elephant Trunk Procedure for Acute Type A Aortic Dissection Using the Left Internal Mammary Artery

The authors present a case of left subclavian artery revascularization during a frozen elephant trunk procedure for acute type A aortic dissection using the left internal mammary artery.

Background

The management of the left subclavian artery (LSA) during a frozen elephant trunk (FET) procedure with debranching of the supraaortic vessels is controversial and sometimes challenging, especially during an emergency life-saving procedure such as a type A acute aortic dissection. Although there are many potential complications following subclavian artery occlusion (including stroke, spinal cord ischemia, or upper limb ischemia), if LSA coverage is necessary during FET, it is still debated whether it should be revascularized or not.

The “gold standard” for LSA revascularization includes direct revascularization (end-to-end anastomosis), carotid-subclavian artery bypass, and aorto-subclavian/axillary bypass. Complications include vocal cord paralysis, phrenic nerve palsy, vagus nerve injury, brachial plexus injury, bleeding, thoracic duct injury, lymphocele, sympathetic nerve injury resulting in Horner’s syndrome, unfavorable anatomy, calcifications, anomalous origin, and left subclavian artery dissection. It can be technically demanding, especially for inexperienced surgeons and during emergency surgery.

The authors describe a novel technique to revascularize the LSA during FET with aortic arch debranching: LIMA harvesting (as a conventional CABG), LIMA distal anastomosis to the ascending aorta/vascular prosthesis with consequent blood “backflow” LIMA to LSA, and closure of the LSA (direct/plug).

Postoperative images of the aorta 3D computed tomography (CT) scan reconstruction image of the thoracic aorta showed the patency of the innominate trunk, the LCA, the LSA, the LIMA graft, and the left vertebral artery. Vascular echo color Doppler showed good flow but slightly lower flow velocity in the left SA versus the right SA. Transcranial Doppler (TCD) showed evidence of antegrade flow in the left vertebral artery.

In conclusion, this case shows that LSA revascularization using the LIMA anastomosed to the ascending aorta to achieve blood ‘backflow’ during FET with arch debranching is technically feasible and seems easy and reproducible, especially in an emergency setting, and it can be an alternative when other techniques are not possible. Follow-up angio-CT scan, vascular echo Doppler, and TCD showed good patency of the bypass with excellent flow in the LSA and antegrade flow in the left vertebral artery. Surgeons should weigh the benefit of LSA prophylactic revascularization during a life-saving operation, taking into consideration the potential surgical risks, such as increasing CPB time and bleeding risk. Further follow-up data are needed to assess the long-term safety and efficacy of this novel technique.

References

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