Use of carotid–subclavian arterial bypass and thoracic endovascular aortic repair to minimize cerebral ischemia in total aortic arch reconstruction

Analysis of Flow Through Extra-Anatomic Bypasses Between Supra-Aortic Branches Using Particle Image Velocimetry (PIV)

Supra-aortic extra-anatomic debranch (SAD) are prosthetic surgical grafts used to revascularize head and neck arteries that would be blocked during a surgical or hybrid procedure used in treating ascending and arch of the aorta pathologies. However, bypassing the supra-aortic arteries but not occluding their orifice might introduce potential for competitive flow that reduces bypass patency. Competitive flow within the bypasses across the supra-aortic arteries has not previously been identified. This research identified haemodynamics due to prophylactic inclusion of bypasses from the brachiocephalic artery (BCA) to the left common carotid artery (LCCA), and from the LCCA to left subclavian artery (LSA). Four model configurations investigated the risk of competitive flow and the necessity of intentionally blocking the proximal LSA and/or LCCA. Particle image velocimetry (PIV) was used to assess haemodynamics in each model configuration. We found potential for competitive flow in the BCA-LCCA bypass when the LSA was blocked, in the LSA-LCCA bypass, when the LCCA alone or LCCA and LSA were blocked. Flow stagnated at the start of systole within the RCCA-LCCA bypass, along with notable recirculation zones and reciprocating flow occurring throughout systolic flow. Flow also stagnated in the LCCA-LSA bypass when the LCCA was blocked. There was a large recirculation in the LCCA-LSA bypass when both the LCCA and LSA were blocked. The presence of competitive flow in all other configurations indicated that it is necessary to block or ligate the native LCCA and LSA once the debranch is made and the thoracic endovascular aortic repair (TEVAR) completed.

Computational fluid dynamics of a novel perfusion strategy during hybrid thoracic aortic repair

BACKGROUND AND AIM

To mitigate the risk of perioperative neurological complications during frozen elephant trunk procedures, we aimed to computationally evaluate the effects of direct cerebral perfusion strategy through a left carotid-subclavian bypass on hemodynamics in a patient-specific thoracic aorta model.

METHODS

Between July 2016 and March 2019, 11 consecutive patients underwent frozen elephant trunk operation using the left carotid-subclavian bypass with a side graft anastomosis and right-axillary cannulation for systemic and brain perfusion. A multiscale model realized coupling three-dimensional computational fluid dynamics was developed and validated with in vivo data. Model comparison with direct antegrade cannulation of all epiaortic vessels was performed. Wall shear stress, wall shear stress spatial gradient, and localized normalized helicity were selected as hemodynamic indicators. Four cerebral perfusion flows were tested (6 to 15 mL/kg/min).

RESULTS

Direct cerebral perfusion of the left subclavian bypass resulted in higher flow rates with augmented speeds in all epiaortic vessels in comparison with traditional perfusion model. At the level of the left vertebral artery (LVA), a speed of 22.5 vs 21 mL/min and mean velocity of 3.07 vs 2.93 cm/s were registered, respectively. With a cerebral perfusion flow of 15 mL/kg, lower LVA wall shear stress (1.596 vs 2.030 N/m² ), and wall shear stress gradient (1445 vs 5882 N/m³ ) were observed. A less disturbed flow considering the localized normalized helicity was documented. No patients experienced neurological/spinal cord damages.

CONCLUSIONS

Direct perfusion of a left carotid bypass proved to be cerebroprotective, resulting in a more physiological and stable anterior and posterior cerebral perfusion.

Total Endovascular Aortic Arch Repair with Branched Graft

In selected cases, the utilization of branched endografts for the treatment of aortic arch aneurysms could be a safe and advantageous alternative to high-risk procedures such as open total aortic arch replacement or hybrid arch repair. We present the case of a 70-year-old man with saccular aneurysm of a bovine aortic arch which was endovascularly treated using a double-branched custom-made aortic endoprosthesis based on the Relay NBS (Non-Bare Stent) Plus platform intended for zone 0 deployment. The postoperative clinical course was uneventful. The postoperative computed tomography scan showed a good result of the implant. The patient was discharged 6 days after the procedure.

One-stage aortic replacement for type A aortic dissection: using a Vasoring and a conventional elephant trunk graft

OBJECTIVES

We used a vascular ring connector (Vasoring) and a conventional elephant trunk graft for complete repair in open surgery for type A aortic dissection. This report described the immediate and mid-term results of this new technique.

METHODS

We used a rigid titanic ring as a stent in the vascular graft for rapid sutureless anastomosis in the reconstruction of type A aortic dissection.

RESULTS

A total of 65 consecutive patients with Stanford type A aortic dissection underwent open surgery performed by a single surgeon from November 2007 to February 2017. All patients underwent aortic reconstruction with vascular grafts and Vasorings (21 patients in the ascending aorta and 44 patients in the total aortic arch). For total aortic arch replacement, we implanted the conventional vascular graft in the proximal descending thoracic aorta as an elephant trunk graft. Concomitant procedures included the Bentall procedure (9 patients), the David operation (6 patients), coronary artery bypass grafting (9 patients), heart transplantation (1 patient), mitral valve replacement (2 patients) and endovascular aortic repair (1 patient). The mean duration of postoperative endotracheal intubation was 17.0 ± 11.8 h. The average blood loss was 520 ± 743 ml, and 25% of patients required no blood transfusion. The in-hospital mortality rate was 6%.

CONCLUSIONS

The combined use of the vascular ring connector and the conventional elephant trunk graft may reduce bleeding and pump time, stop the blood flow in the false lumen and allow the 1-stage total arch replacement to be performed safely. The conventional elephant trunk graft is free from stent graft-induced new entry.

Single Institution Experience with Hybrid Endovascular and Surgical Repairs Involving the Distal Aortic Arch

BACKGROUND

A hybrid approach of aortic arch and descending aorta pathology, involving surgical debranching of the great vessels after endovascular stenting, has been increasingly used as an alternative to entirely open surgical repair. This study reviews and reports our single-center experience with hybrid aortic arch repair over the span of a decade.

METHODS

A total of 43 patients who underwent hybrid arch repair from 2005 to 2015 were identified. Key endpoints included the presenting pathology, perioperative details, and postoperative outcomes.

RESULTS

The mean age was 64.9 years at the commencement of surgery (61.4% men [n = 27] and 38.6% women [n = 16]). Presenting pathologies included aneurysms (77%), dissections (16%), pseudoaneurysms (5%), and transections (2%). While most procedures were multistaged, single-stage interventions were completed for 16.3% (n = 7) of patients. Emergent surgeries were performed in 23.3% of cases; the remaining 76.7% of cases were elective. The proximal extents of endovascular repair were zone 0 (n = 4), zone 1 (n = 12), zone 2 (n = 20), and zone 3 (n = 1). The remaining 6 patients had had aberrant or anomalous distal origins of a great vessel that required debranching. Technical success rates of surgical revascularizations and subsequent endovascular stenting were both 100%. The 30-day perioperative event rates for mortality, stroke, and cardiac events were 7.0% (n = 3), 4.7% (n = 2), and 9.3% (n = 4), respectively. At the end of 2-year follow-up, total mortality and stroke rates were 11.6% (n = 5) and 7.0% (n = 3), respectively. The 2-year primary patency of the revascularizations was 97.8%, and the associated primary-assisted patency was 100%. Secondary interventions were necessary for 32% (n = 12) of the patients, 67% of which (n = 8) were warranted because of endoleaks. The remaining secondary interventions were required to resolve device migration (n = 1), stent graft stenosis (n = 1), and disease progression (n = 2).

CONCLUSIONS

Hybrid approaches are viable alternatives to entirely open surgical treatments of acute and chronic aortic arch pathology and may be particularly attractive for high-risk patients. Surgical revascularizations appear durable, but endovascular reintervention is not uncommon and highlights the need for careful surveillance after repair.

Hybrid repair of aortic arch aneurysms: a comprehensive review

Open total arch replacement (TAR) has become safer with refinements in cerebral protection techniques. The frequent extension of aortic arch aneurysms into the descending thoracic aorta customarily requires a two-staged conventional elephant trunk procedure, carrying relatively high mortality and morbidity risks and high rates of rupture in the interval between the two open surgeries. The technical demands and invasive nature of TAR has therefore precluded many high-risk patients from being surgical candidates for aneurysm repair. As a result, hybrid techniques and approaches to the aortic arch have become common since the adoption of thoracic endovascular aortic repair (TEVAR) and advancement in the commercial grafts that are available. The results of hybrid aortic arch repairs have been encouraging, though with higher rates of re-interventions than TAR and variable reported rates of stroke and spinal cord ischemia. The aim of this publication is to review the current literature on hybrid repair of aortic arch aneurysms.

Treatment of subclavian artery stenosis: A case series

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Case presentation of a patient treated with subclavian artery stenting.

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Case presentation of a patient treated with transposition of the left subclavian artery onto the left common carotid artery.

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Case presentation of a patient treated with carotid- subclavian artery bypass with a PTFE graft.

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Case presentation of a patient treated with carotid to axillary bypass.

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Discussion and literature review of methods and indications of treatment of subclavian artery occlusive disease.

Introduction

In this case series, different modalities of treatment for patients with ischaemic symptoms of subclavian stenosis are described, including the different operative strategies that can be adopted in more challenging cases. This is the first case series describing these four management options.

Presentation

Case 1: A seventy-one year-old female presented with acute on chronic ischaemia of her left arm following a fall and developed dry gangrene of her left thumb. This was initially managed with a heparin infusion followed by stenting of the subclavian artery which relieved her symptoms. Case 2: A fifty-nine year-old male presented with chronic ischemia of the left arm secondary to an occlusion of the left subclavian artery. This was managed by transposition of the left subclavian artery onto the left common carotid artery. Case 3: A sixty-four year-old female presented with left subclavian steal syndrome secondary to subclavian artery stenosis. She underwent carotid subclavian artery bypass. Case 4: A fifty-six year-old female presented with acute left upper limb ischaemia secondary to acutely thrombosed subclavian artery on a CT-angiography. She underwent a carotid to axillary bypass.

Discussion and conclusion

This case series demonstrates the treatment options available to vascular surgeons when managing symptomatic subclavian artery disease. Symptomatic subclavian artery occlusive disease should be treated with endovascular stenting and angioplasty as first line management. If it is not successful then open surgery should be considered. Bypassing the carotid to the subclavian or to the axillary artery are both good treatment modalities.

Extra-Anatomic Bypass Operation for an Infected Aortic Arch Aneurysm with Broad Mediastinal Abscess: A Case Report

We encountered an informative case of infected aortic arch aneurysm. The proximal descending aorta, left common carotid artery, and left subclavian artery were severely involved in an abscess; thus, typical in situ reconstruction of the arch was considered impossible. Therefore, to secure more distal branches appropriate for anastomosis, a modified extra-anatomic arch repair was performed through additional incisions. The patient developed renal and respiratory failure and died of septicemia five and a half months after the operation. However, postoperative computed tomograms demonstrated that the abscess had disappeared.

Arch debranching versus elephant trunk procedures for hybrid repair of thoracic aortic pathologies

BACKGROUND

We compared outcomes of arch debranching (AD) and elephant trunk (ET) techniques when used with thoracic endovascular aortic repair.

METHODS

A review was performed of consecutive patients with proximal thoracic aortic pathologies repaired with a hybrid approach.

RESULTS

Between 2005 and 2009, 58 patients underwent first-stage ET (n = 21) or AD (n = 37). Cardiopulmonary bypass was utilized in 100% of ET procedures and 68% of AD procedures (p < 0.01). Circulatory arrest was used in 86% of ET and 27% of AD cases (p < 0.01). The second stage was completed in 76% of ET and 76% of AD patients. Rates of spinal cord ischemia (ET 0 of 21, AD 0 of 37, p = 1.0), stroke (ET 2 of 21, AD 4 of 37, p = 1.0), and 30-day mortality (ET 4 of 21, AD 6 of 37, p = 1.0) were similar. Each group had one major aortic complication between the two stages. Type Ia endovascular leak at 1 and 12 months occurred in 13% ET patients and 4% AD patients at 1 month (p = 0.54) and in 0% ET patients and 4% AD patients at 12 months (p = 1.0). Kaplan-Meier estimates of survival at 1 and 12 months were 90.5% ± 6.4% and 73.1% ± 10% in the ET group, and 86.5% ± 5.6 and 71.6% ± 8.5 in the AD group, respectively (p = 0.68). The risk of a secondary procedure at 1 and 12 months was 76.2% ± 9.3% and 58.7% ± 12% in the ET group, and 71.0% ± 7.8% and 52.8% ± 10% in the AD group, respectively (p = 0.86).

CONCLUSIONS

Arch debranching achieves equivalent results to standard elephant trunk repair but with a decreased need for cardiopulmonary bypass and circulatory arrest.

Scalloped thoracic stent-graft for treatment of aortic arch aneurysms with unfavourable landing zones

Endovascular treatments are limited in cases of thoracic aortic aneurysms extending up or proximal to the origin of the left subclavian artery (LSCA). In such cases, the LSCA is usually either occluded or revascularised. We report our first experience of four patients who underwent thoracic aneursym treatment with new custom-made grafts with a scallop in situ for the LSCA. The graft is tailor made per case, and a re-enforced scallop is positioned proximally allowing for the stent to be deployed beyond the origin of the LSCA; the origin of the LSCA remains patent, thus negating the need for revascularisation of the head and neck vessels on the left. The stent contains markers for identifying the scallop and are located along the midline to ensure correct alignment. All of the patients who underwent this procedure had technical success with flow through the LSCA both immediately after stent deployment and on follow-up imaging. This new stent has further expanded endovascular treatment options for patients with thoracic aneurysms extending up to and beyond the LSCA, which can play a part in improving outcome and decreasing mortality rates because surgery for revascularization will not be needed.