Intrapleural left axillary artery bypass grafting compromising subsequent left internal thoracic artery harvesting: a case report

Abstract

The frozen elephant trunk technique is increasingly used in total arch replacement (TAR) for acute Type A aortic dissection, with left axillary artery bypass commonly employed for left subclavian artery revascularization. We report a case in which an intrapleural left axillary artery Dacron bypass graft led to dense perigraft adhesions that severely compromised subsequent left internal thoracic artery (LITA) harvesting during redo coronary artery bypass grafting. A 45-year-old man underwent valve-sparing aortic root reimplantation, TAR, and left axillary artery bypass. Intraoperative findings revealed dissection extending to the left main trunk ostium, necessitating an arch prosthesis-to-left anterior descending saphenous vein graft, which subsequently failed. Dense intrapleural adhesions surrounding the graft severely impaired LITA harvesting. Complete arterial revascularization was achieved using bilateral internal thoracic arteries and radial artery bridge conduits. This case highlights that intrapleural routing of a left axillary artery bypass graft may compromise future LITA harvesting.

Introduction

The frozen elephant trunk (FET) technique has become a standard approach for total arch replacement (TAR) in patients with acute Type A aortic dissection. As the use of FET has become widespread, there has been a growing trend toward proximalization of the distal anastomosis to Zone 0, 1, or 2, with extra-anatomic bypass grafting to the left axillary artery (Lt. AxA) increasingly employed for left subclavian artery revascularization [1, 2]. However, the implications of this strategy for future coronary revascularization have received little attention.

When a Lt. AxA bypass graft is routed through the left pleural cavity, it runs in close proximity to the left internal thoracic artery (LITA)—the gold-standard conduit for coronary artery bypass grafting (CABG)—and may cause dense adhesions that compromise subsequent LITA harvesting. To our knowledge, the impact of a Lt. AxA bypass graft on subsequent LITA harvesting has not previously been reported.

We present a case in which dense adhesions surrounding an intrapleural Lt. AxA Dacron graft severely impaired subsequent LITA harvesting during CABG. Despite this challenge, complete arterial revascularization was successfully achieved using bilateral internal thoracic arteries and radial artery bridge conduits.

Case report

A 45-year-old man with no prior cardiac history presented with sudden chest and back pain. Computed tomography (CT) revealed acute Type A aortic dissection extending from the aortic root to both common iliac arteries, with a Valsalva sinus diameter of 58 mm (Fig. 1). Involvement of the coronary arteries could not be clearly assessed on preoperative imaging. Severe aortic regurgitation was confirmed by transesophageal echocardiography.

Emergency valve-sparing aortic root reimplantation (David procedure) combined with TAR using the FET technique was performed under cardiopulmonary bypass with deep hypothermic circulatory arrest and selective cerebral perfusion. Because the dissection involved the origin of the left subclavian artery, TAR was completed with a Zone 1 distal anastomosis, and an 8-mm Dacron graft was constructed from the arch prosthesis to the Lt. AxA and routed through the left pleural cavity. Intraoperatively, the dissection was found to extend to the left main trunk (LMT) ostium. The LMT was therefore ligated, and an additional saphenous vein graft (SVG) bypass to the left anterior descending artery (LAD) was performed, with the proximal anastomosis constructed on the arch prosthesis. The postoperative course was uneventful, and the patient was discharged on postoperative day (POD) 16.

On POD 57, the patient presented with chest tightness. Coronary angiography revealed severe stenosis at the proximal SVG anastomosis (Fig. 2), and emergent percutaneous coronary intervention with a drug-eluting stent was performed.

Given the patient’s young age, early SVG failure, and concerns regarding in-stent restenosis, the heart team planned elective redo CABG using exclusively arterial conduits. Preoperative three-dimensional CT angiography (3DCTA) demonstrated the intrapleural Lt. AxA Dacron graft coursing in extremely close proximity to the LITA (Fig. 3), raising concern regarding subsequent LITA harvesting.

Redo sternotomy was performed on POD 88. Dense mediastinal adhesions resulted in inadvertent injury to the SVG near its proximal anastomosis during dissection. Repair required short SVG interposition, and the total aortic cross-clamp time was 155 minutes. Given the prolonged ischemic time and resulting coagulopathy, the procedure was staged, and the operation was terminated after completion of mediastinal dissection.

Two days later, harvesting of both internal thoracic arteries was attempted. The right internal thoracic artery (RITA) was harvested without difficulty. In contrast, the LITA was densely encased within fibrotic tissue surrounding the intrapleural Dacron graft, consistent with the preoperative 3DCTA findings. Dense adhesions severely hindered LITA harvesting, and dissection of the LITA occurred, leaving only a short proximal segment suitable for grafting. Radial artery grafts were therefore used as bridge conduits, and RITA–radial artery–LAD and LITA–radial artery–ramus intermedius (RI) composite grafts were constructed. The patient recovered uneventfully and was discharged home 16 days after the second-stage procedure. Postoperative 3DCTA confirmed patency of all grafts (Fig. 4).

Discussion

LMT ostial involvement occurs in ~10% of patients with acute Type A aortic dissection and may necessitate concomitant CABG [3]. In the context of an emergency procedure of this complexity, harvesting of the LITA is often impractical because of time constraints and the demands of the primary repair. When LMT involvement is identified only intraoperatively, LITA harvesting is even less feasible. However, the long-term durability of saphenous vein grafts remains a concern, particularly in young patients. In the present case, early stenosis of the proximal SVG anastomosis necessitated repeat coronary revascularization.

The principal challenge in this case arose from the intrapleural routing of the Lt. AxA Dacron graft, which placed it in extremely close proximity to the LITA. The intrapleural Dacron graft likely contributed to the dense adhesions surrounding the LITA, as prosthetic implants are known to induce a foreign-body reaction and perigraft fibrosis [4]. Preoperative 3DCTA demonstrated this anatomical relationship and facilitated planning of an alternative conduit strategy.

Redo CABG was performed ~3 months after the index operation, when mediastinal adhesions are typically well established [5]. In this case, however, the LMT had been ligated at the index operation, rendering the left coronary territory completely dependent on the SVG. Because in-stent restenosis or SVG occlusion could have caused critical left coronary ischemia, delaying redo CABG was not considered acceptable despite the unfavorable timing.

The close proximity of the intrapleural Lt. AxA graft to the LITA has important implications for future coronary revascularization. Had the graft been routed extrapleurally, close proximity to the LITA might have been avoided, potentially reducing adhesion formation around the LITA and facilitating future LITA harvesting. As proximalization of the distal anastomosis and extra-anatomic Lt. AxA bypasses become increasingly common in the FET era, the potential impact of graft routing on future coronary revascularization deserves consideration, particularly in young patients who may require future CABG.

Despite the severely limited usable LITA length, complete arterial revascularization was achieved using radial artery bridge conduits in combination with bilateral internal thoracic arteries [6]. The staged strategy allowed correction of coagulopathy before definitive coronary revascularization. This case highlights that intrapleural Lt. AxA bypass grafting may compromise subsequent LITA harvesting. Preoperative recognition of this anatomical relationship is essential for planning alternative arterial revascularization strategies.

Author contributions

H.W. performed the surgical procedure and was responsible for the conception and design of this report. All authors were involved in the clinical care of the patient and contributed to the drafting or critical revision of the manuscript. All authors have read and approved the final version of the manuscript.

Conflicts of interest

None declared.

Funding

None declared.

Data availability

Not applicable.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Written informed consent was obtained from the patient for the publication of this case report and the accompanying images.

References