Management of the difficult left subclavian artery during aortic arch repair

A challenging case of emergency redo surgery for acute type A aortic dissecting aneurysm of ascending and aortic arch with frozen elephant trunk following aortic root replacement

Redo ascending and aortic arch surgeries following previous cardiac or aortic surgery are associated with high risk of morbidity and mortality due to multiple factors included sternal re-entry injury, extensive aortic arch surgery, emergency aortic surgery, prolonged cardiopulmonary bypass duration, poor heart function, and patients with older age. Therefore, appropriate surgical strategies are important. We report a case of a 72-year-old gentleman with previous surgery of aortic root replacement who presented with acute Type A aortic dissecting aneurysm of ascending and aortic arch complicated with left hemothorax, which was successfully treated by emergency redo aortic surgery with frozen elephant trunk (FET) technique.

Extra-anatomical left common carotid and subclavian artery bypass followed by aortic arch replacement with frozen elephant trunk

BACKGROUND

Total arch replacement (TAR) using a frozen elephant trunk (FET) allows for simultaneous treatment of the aortic arch and descending aortic pathology via median sternotomy. In addition, an extra-anatomical bypass performed between the left common carotid artery (CCA) and subclavian artery (SCA) prior to TAR allowed further proximalisation of the FET prosthesis, facilitated distal anastomosis of the TAR and spared the demanding left subclavian artery (LSA) anastomosis in the deep thorax. We investigated the efficacy of this debranching-first technique, followed by TAR using a frozen elephant trunk, as a two-stage operation for extensive thoracic aortic aneurysms in high-risk patients.

METHODS

Forty-nine consecutive patients with diffuse degenerative aneurysms from the aortic arch to the descending aorta or chronic aortic dissection who underwent left common carotid to subclavian artery bypass followed by TAR using a frozen elephant trunk and subsequent thoracic endovascular aortic repair between 2016 and 2021 were analysed. The baseline characteristics and clinical outcomes were assessed. The estimated overall survival, 5-year aortic event-free survival, and aortic reintervention rates were analysed.

RESULTS

The average European System for Cardiac Operative Risk Evaluation (EuroSCORE II) was 4.7 ± 2.5. The operative mortality rate was 4.1%, with no paraplegia events. The estimated 5-year overall survival, cumulative aortic-related mortality rates were 76.8% and 2%, respectively. The estimated 5-year overall cumulative aortic reintervention rate, including the intended intervention, was 31.3%. The estimated 5-year cumulative rate of non-intended reintervention was 4.5%.

CONCLUSIONS

The assessed technique enables a less technically demanding surgery with reasonable outcomes. The estimated 5-year aortic event-free survival and reintervention rates were acceptable, suggesting that multiple stages of alternative open and endovascular interventions, such as this technique, may reduce the morbidity and mortality rates of high-risk patients with diffuse thoracic aortic aneurysm. UMIN-CTR (University hospital Medical Information Network-Clinical Trial Registry) https://center6.umin.ac.jp/cgi-open-bin/ctr_e/index.cgi Clinical registration number: UMIN000051531.

Early Feasibility of Endovascular Repair of Distal Aortic Arch Aneurysms Using Patient-Specific Single Retrograde Left Subclavian Artery Branch Stent Graft

OBJECTIVE

To describe the feasibility and outcomes of endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with a pre-loaded single retrograde left subclavian artery (LSA) branch stent graft.

METHODS

We reviewed the clinical data and outcomes of consecutive patients enrolled in an ongoing prospective, non-randomized physician-sponsored investigational device exemption study to evaluate the outcomes of endovascular aortic arch repair using patient-specific arch branch stent grafts (William Cook Europe, Bjaeverskov, Denmark) between 2019 and 2022. All patients received a design with triple-wide scallop and a single retrograde LSA branch with a pre-loaded catheter.

RESULTS

There were five male patients with median age of 77 years old (72-80) treated using the single LSA branch stent graft. Technical success was achieved in all patients. Median operating time, fluoroscopy time, and total radiation dose area product were 103 (78-134) minutes, 26 (19-39) minutes, and 123 (71-270) mGy.cm2, respectively. There were no 30-day or in-hospital mortality, neurological or other major adverse events (MAEs). During median follow-up of 21 (20-27) months, all patients were alive with patent LSA branches, except for one who died of COVID-19 complications. There was no branch instability or secondary interventions.

CONCLUSION

This early feasibility study demonstrates successful endovascular repair of distal aortic arch aneurysms using a patient-specific stent graft with single retrograde LSA branch without technical failures, mortality or neurological events. Larger clinical experience and longer follow-up are needed to determined effectiveness of this approach in patients who need endovascular repair with proximal extension into Zone 2.

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.

Open arch surgery in the redo setting: contemporary outcomes

BACKGROUND

Aortic arch reconstruction after prior cardiac surgery is technically complex, especially after proximal aortic surgery. While multiple surgical adaptations in the redo setting have been described, traditional open reconstruction remains the most common approach with significant variability in outcomes in prior reports. This study describes institutional adaptations to surgical technique and perioperative care and assesses operative and long-term outcomes after redo-aortic arch repair in the modern era.

METHODS

Patients undergoing hemi- or total arch reconstruction after prior cardiac surgery (2005-2022) were identified from a prospectively maintained institutional database. Strategic adaptations in approach over the study interval included a shift towards Type II hybrid arch repair for patients with "mega-aorta," redo-cannulation of the axillary artery when necessary, and adoption of transfusion and early extubation protocols. Outcomes of interest included 30-day/in-hospital adverse events and actuarial long-term overall and aorta-specific survival.

RESULTS

The study cohort included 214 patients undergoing hemi-arch (N.=154, 72%) or total arch (N.=60, 28%) after prior cardiac surgery (50% prior proximal aortic surgery). Surgical indications included degenerative aneurysm (47%, N.=101), residual arch dissection after prior type A repair (29%, N.=61), acute or chronic type A dissection (18%, N.=39) or other (6%, N.=13). 30-day/in-hospital mortality was 6% (5% hemi-arch; 10% total arch) and stroke was 3% (3% hemi-arch; 2% total arch). At median follow-up of 56 months, overall 5- and 10-year survival was 76% and 58% (hemi-arch: 81%, 62%; total arch: 63%, 43%); aorta-specific survival was 91% and 90% (hemi-arch: 96%, 94%; total arch: 79%, 79%).

CONCLUSIONS

In this modern single-institution series, a systematic approach to redo-arch repair yields excellent operative outcomes and late aorta-specific survival. Reduced late overall survival reflects the comorbidity burden of this population. Open reconstruction continues to play an important role in reoperative arch repair in the modern era.

Revascularization of Left Subclavian to Common Carotid Artery Prepares for Covered Stent Implantation in Patients With Complex Aortic Coarctation

Seven adult patients underwent a two-stage treatment of complex coarctation (CoA), including surgical revascularization of the left subclavian artery (LSA) to left common carotid artery (LCCA), followed by transcatheter covered stent implantation. The majority of patients (5 of 7, 71%) received 1 covered stent (covered Cheatham Platinum stent: 8 zig/45 mm [n = 2], 10 zig/60 mm [n = 1], 10 zig/65 mm [n = 1]; BeGraft: 24/48 mm [n = 2]). In 1 patient (14%), the implantation of 2 covered stents (BeGraft 20/48 mm) was necessary. During a median follow-up of 2.4 years (interquartile range, 0.1 to 4.9 years), complications occurred in 3 of 7 patients (43%), including an asymptomatic but severe stenosis of the LSA bypass (n = 1), a recoarctation with a mild endoleak (n = 1), and a severe endoleak (n = 1). Surgical revascularization of the LSA to the LCCA can successfully prepare for covered stent implantation in complex CoA in adult patients. This two-stage approach was feasible and safe with complications occurring in 3 of 7 patients (43%). All complications were managed by catheter reintervention only.

Reconstruction of the left subclavian artery in arch repair: An end-to-side anastomosis technique

BACKGROUND

The left subclavian artery (LSCA) is deeply located and difficult to visualize in some cases of total arch replacement.

AIMS

We report an end-to-side anastomosis technique that enables safer and easier anatomical reconstruction of the LSCA.

MATERIALS AND METHODS

Under Hypothermic circulatory arrest, the origin of the LSCA was ligated and pulled caudally. With clamping the distal LSCA, a graft was anastomosed to the anterior wall of the LSCA and antegrade cerebral perfusion to the LSCA was ensured through the anastomosed graft. Thereafter, distal anastomosis was performed proximal to the LSCA.

RESULTS

The postoperative course was uneventful.

DISCUSSION

Our reconstruction technique provides excellent exposure of the LSCA by pulling the origin of the LSCA caudally. Hemostasis after reconstruction is feasible, as the anastomosis in the anterior wall of the LSCA is easily visualized.

CONCLUSION

The end-to-side anastomosis technique for LSCA reconstruction is a simple alternative in arch repair.

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.

The fate of the left subclavian artery in TEVAR for aortic arch pathology

BACKGROUND AND AIM OF STUDY

The origin of the vertebral artery (VA) from the left subclavian (LSA) is variable and must be considered when proximal ligation or embolization is performed post thoracic endovascular aortic repair (TEVAR) and extra-anatomical bypass (EAB). A retrospective study was conducted to understand the patency of the LSA and VAs after TEVAR and the relationship of the EAB to the LSA.

METHODS

Fifty-six patients underwent TEVAR where the LSA origin was occluded. A comparison was performed between the length of the proximal LSA from the arch of the aorta to the origin of the VA. Patient outcomes included posterior or anterior circulation cerebrovascular accident, spinal cord ischemia (SCI), and symptoms and signs of left arm ischemia (LAI). Thirty one underwent EAB with 8 undergoing occlusion of the LSA proximal to the origin of the left VA. A further 25 underwent TEVAR with no EAB performed. The mean (standard deviation) of origin of the VA from the origin at the arch was 37.0 (12.9) mm compared to 34.0 (13.7) mm in those where no bypass was performed (p 0.45). Four patients underwent intraluminal plug occlusion and four had external ligation of the proximal LSA in those undergoing EAB.

CONCLUSIONS

Careful evaluation of the LSA is needed when planning TEVAR as occlusion techniques may be dependent on a minimum length of the VA from the aortic arch. The mean length of the VA from the aorta has high heterogeneity which may dictate the optimum occlusion method for LSA.

Hybrid arch frozen elephant trunk repair: evidence from the Canadian Thoracic Aortic Collaborative

Background

The frozen elephant trunk (FET) technique has become an increasingly popular strategy for aortic reconstruction in the setting of extensive thoracic aortic aneurysms or dissections. The objective of this study is to report on the Canadian experience with the FET technique in both the elective and emergent settings.

Methods

A total of 167 consecutive patients (mean age 65±13 years, 30% female, 25% re-operation) underwent elective (70%) and non-elective (30%) aortic arch reconstruction with the FET technique between May 2008 and October 2019 in six centers of the Canadian Thoracic Aortic Collaborative (CTAC). In-hospital clinical endpoints and early imaging endpoints were prospectively collected and analyzed.

Results

All 167 patients underwent successful FET implantation. In-hospital mortality occurred in 14 patients (8%), stroke occurred in 22 patients (13%) and temporary and permanent spinal cord ischemia (SCI) occurred in 6 (3.6%) and 3 (1.8%) patients, respectively. Prolonged mechanical ventilation was required in 35 patients (21%), renal failure requiring dialysis in 14 patients (8%) and atrial fibrillation in 59 patients (36%). The median hospital and intensive care unit (ICU) lengths of stay were 3 [interquartile range (IQR): 1, 6] and 10 (IQR: 7, 17) days, respectively. The rate of type 1A endoleak was 3.6%, with the lowest rate in patients who underwent a total arch replacement with a hybrid FET graft (0%) and the highest among patients who had a hemiarch with antegrade thoracic endovascular aortic repair (TEVAR) deployment (25%). The rate of other types of endoleak and stent complications was comparatively low.

Conclusions

The early CTAC experience with the FET operation demonstrates technical feasibility and good early clinical outcomes in elective and emergent patients. Further analysis is required to explore variations in technique and their potential impact on early and late outcomes.

Prevention and management of spinal cord ischemia following aortic surgery: A survey of contemporary practice

OBJECTIVE

Spinal cord ischemia (SCI) is a devastating complication of thoracoabdominal aortic aneurysm repair. We aim to characterize current practices pertaining to SCI prevention and treatment across Canada.

METHODS

Two questionnaires were developed by the Canadian Thoracic Aortic Collaborative and the Canadian Cardiovascular Critical Care Society targeting aortic surgeons and intensivists. A list of experts in the management of patients at risk of SCI was developed, with representation from each of the Canadian centers that perform complex aortic surgery.

RESULTS

The response rate was 91% for both intensivists (21/23), and from cardiac and vascular surgeons (39/43). Most surgeons agreed that staging is important during endovascular repair of extent II thoracoabdominal aortic aneurysm (60%) but not for open repair (34%). All of the surgeons felt prophylactic lumbar drains were effective in reducing SCI, whereas only 66.7% of intensivists felt that lumbar drains were effective (P < .001). There was consensus among surgeons over when to employ lumbar drains. A majority of surgeons preferred to keep the hemoglobin over 100 g/L if the patient demonstrated loss of lower-extremity function, whereas most intensivists felt a target of 80 g/L was adequate (P < .001). Management of perioperative antihypertensives, use of intraoperative adjuncts, and management of venous thromboembolism prophylaxis in the presence of a lumbar drain, were highly variable.

CONCLUSIONS

We observed some consensus but considerable variability in the approach to SCI prevention and management across Canada. Future studies focused on the areas of variability may lead to more consistent and improved care for this high-risk population.