Should intentional endovascular stent-graft coverage of the left subclavian artery be preceded by prophylactic revascularisation?

Thoracic endovascular aortic repair (TEVAR) has emerged as a promising therapeutic alternative to conventional open aortic replacement but it requires suitable proximal and distal landing zones for stent-graft anchoring. Many aortic pathologies affect in the immediate proximity of the left subclavian artery (LSA) limiting the proximal landing zone site without proximal vessel coverage. In patients in whom the distance between the LSA and aortic lesion is too short, extension of the landing zone can be obtained by covering the LSA's origin with the endovascular stent graft (ESG). This manoeuvre has the potential for immediate and delayed neurological and vascular symptoms. Some authors, therefore, propose prophylactic revascularisation of the LSA by transposition or bypass, while others suggest prophylactic revascularisation only under certain conditions, and still others see no requirement for prophylactic revascularisation in anticipation of LSA ostium coverage. In this review about LSA revascularisation in TEVAR patients with coverage of the LSA, we searched the electronic databases MEDLINE and EMBASE historically until the end date of May 2010 with the search terms left subclavian artery, covering, endovascular, revascularisation and thoracic aorta. We have gathered the most complete scientific evidence available used to support the various concepts to deal with this issue. After a review of the current available literature, 23 relevant articles were found, where we have identified and analysed three basic treatment concepts for LSA revascularisation in TEVAR patients (prophylactic, conditional prophylactic and no prophylactic LSA revascularisation). The available evidence supports prophylactic revascularisation of the LSA before ESG LSA coverage when preoperative imaging reveals abnormal supra-aortic vascular anatomy or pathology. We further conclude that elective patients undergoing planned coverage of the LSA during TEVAR should receive prophylactic LSA transposition or LSA-to-left-common-carotid-artery (LCCA) bypass surgery to prevent severe neurological complications, such as paraplegia or brain stem infarction.

Arterial access through the right subclavian artery in surgery of the aortic arch improves neurologic outcome and mid-term quality of life

BACKGROUND: We have shown that selective antegrade cerebral perfusion improves mid-term quality of life in patients undergoing surgical repair for acute type A aortic dissection and aortic aneurysms. The aim of the study was to assess the impact of continuous cerebral perfusion through the right subclavian artery on immediate outcome and quality of life. METHODS: Perioperative data of 567 consecutive patients who underwent surgery of the aortic arch using deep hypothermic circulatory arrest have been analyzed. Patients were divided into three groups, according to the management of cerebral protection. Three hundred eighty-seven patients (68.3%) had deep hypothermic circulatory arrest with pharmacologic protection with pentothal only, 91 (16.0%) had selective antegrade cerebral perfusion and pentothal, and 89 (15.7%) had continuous cerebral perfusion through the right subclavian artery and pentothal. All in-hospital data were assessed, and quality of life was analyzed prospectively 2.4 +/- 1.2 years after surgery with the Short Form-36 Health Survey Questionnaire. RESULTS: Major perioperative cerebrovascular injuries were observed in 1.1% of the patients with continuous cerebral perfusion through the right subclavian artery, compared with 9.8% with selective antegrade cerebral perfusion (p < 0.001) and 6.5% in the group with no antegrade cerebral perfusion (p = 0.007). Average quality of life after an arrest time between 30 and 50 minutes with continuous cerebral perfusion through the right subclavian artery was significantly better than selective antegrade cerebral perfusion (90.2 +/- 12.1 versus 74.4 +/- 40.7; p = 0.015). CONCLUSIONS: Continuous cerebral perfusion through the right subclavian artery improves considerably perioperative brain protection during deep hypothermic circulatory arrest. Irreversible perioperative neurologic complications can be significantly reduced and duration of deep hypothermic circulatory arrest can be extended up to 50 minutes without impairment in quality of life.

Investigation of hemodynamics in an in vitro system simulating left ventricular support through the right subclavian artery using 4-dimensional flow magnetic resonance imaging.

OBJECTIVES Left ventricular assist devices are an important treatment option for patients with heart failure alter the hemodynamics in the heart and great vessels. Because in vivo magnetic resonance studies of patients with ventricular assist devices are not possible, in vitro models represent an important tool to investigate flow alterations caused by these systems. By using an in vitro magnetic resonance-compatible model that mimics physiologic conditions as close as possible, this work investigated the flow characteristics using 4-dimensional flow-sensitive magnetic resonance imaging of a left ventricular assist device with outflow via the right subclavian artery as commonly used in cardiothoracic surgery in the recent past. METHODS An in vitro model was developed consisting of an aorta with its supra-aortic branches connected to a left ventricular assist device simulating the pulsatile flow of the native failing heart. A second left ventricular assist device supplied the aorta with continuous flow via the right subclavian artery. Four-dimensional flow-sensitive magnetic resonance imaging was performed for different flow rates of the left ventricular assist device simulating the native heart and the left ventricular assist device providing the continuous flow. Flow characteristics were qualitatively and quantitatively evaluated in the entire vessel system. RESULTS Flow characteristics inside the aorta and its upper branching vessels revealed that the right subclavian artery and the right carotid artery were solely supported by the continuous-flow left ventricular assist device for all flow rates. The flow rates in the brain-supplying arteries are only marginally affected by different operating conditions. The qualitative analysis revealed only minor effects on the flow characteristics, such as weakly pronounced vortex flow caused by the retrograde flow via the brachiocephalic artery. CONCLUSIONS The results indicate that, despite the massive alterations in natural hemodynamics due to the retrograde flow via the right subclavian and brachiocephalic arteries, there are no drastic consequences on the flow in the brain-feeding arteries and the flow characteristics in the ascending and descending aortas. It may be beneficial to adjust the operating condition of the left ventricular assist device to the residual function of the failing heart.

Asymptomatic high flow subclavian steal in a patient with hemodialysis access.

Subclavian steal phenomenon due to proximal subclavian artery stenosis or occlusion is not un-common but often remains asymptomatic. We describe the case of a 66-year-old man with end-stage renal disease hemodialysed through a brachio-brachial loop graft of the left forearm. Echo-Doppler precerebral examination showed a high reversed flow of 570 ml/min in the ipsilateral vertebral artery. After successful endovascular recanalization of the subclavian artery, access blood flow increased and vertebral flow decreased to 30 ml/min. Complete neurological examination was normal both before and after endovascular treatment. This case demonstrates how high a subclavian steal can be without causing symptoms and how well precerbral and cerebral circulation can adapt to hemodynamic changes.

Ramos do arco aórtico de bubalinos

Os ramos do arco aórtico (Arcus aortae) em bubalinos foram investigados neste trabalho. Assim, foram dissecadas as artérias oriundas desse arco previamente injetadas com solução corada de látex Neoprene 650â (Du Pont do Brasil S.A.) em 20 fetos dessa espécie, machos e fêmeas com idades entre 4 e 8 meses de gestação. em 80% dos casos, observou-se que o tronco braquiocefálico (Truncus brachiocephalicus) emite a artéria subclávia (Arteria subclavia) esquerda, artérias carótidas comuns (Arteria carotis communis) esquerda e direita, sem caracterizar tronco bicarotídeo (Truncus bicaroticus), e a artéria subclávia direita. As artérias subclávias direita e esquerda originam em comum o tronco costocervical (Truncus costocervicalis), a artéria cervical superficial (Arteria cervicalis superficialis), artérias axilares (Arteria axillaris) e artéria torácica interna (Arteria thoracica interna). em 20% dos casos, o tronco braquiocefálico origina a artéria subclávia esquerda em comum ao tronco costocervical esquerdo; em seguida, emite a artéria carótida comum esquerda e termina trifurcando-se em artéria carótida comum direita, artéria subclávia direita e tronco costocervical direito, sendo que as artérias subclávias direita e esquerda têm origem comum com as artérias cervical superficial, axilar e torácica interna, com a presença do tronco bicarotídeo, característico dos bovinos.

Total Endovascular Debranching of the Aortic Arch

Background: Significant morbidity and mortality are related to conventional aortic replacement surgery. Endovascular debranching techniques, fenestrated or branched endografts are time consuming and costly.Objective: We alternatively propose to use endovascular approach with parallel grafts for debranching of aortic arch.Methods: Under general anesthesia, 12 F sheaths were inserted in the femoral, axillary and common carotid arteries for vascular accesses. ViaBahn grafts 10 - 15 cm in length were placed into the aortic arch from right common carotid, left common carotid and left axillary arteries, until the tip of each graft reached into the ascending aorta. Through one femoral artery, the aortic stent-graft was positioned and delivered. Soon after, the parallel grafts were sequentially delivered. Self-spanding Wallstents(R) were used for parallel grafts reinforcement. Ballooning was routinely used for parallel grafts and rarely for aortic graft.Results: This technique was used in 2 cases. The first one was a lady with 72 years old, with an aortic retrograde dissection from left subclavian artery and involving remaining arch branches. Through right common carotid artery a stent-graft was placed in the ascending aorta and through the left common carotid artery a ViaBahn was inserted parallel to the former. A thoracic endograft then covered all the aortic arch dissection extending into the ascending aorta close to the sinu-tubular junction. The second case was a 82 year old male patient with a 7 cm aortic arch aneurysm. Through both common carotid arteries ViaBahn grafts were introduced and positioned into the ascending aorta. Soon after, the deployment of the thoracic stent graft covered all parallel grafts of the aortic arch, excluding the aneurysm. Both cases did not have neurologic or cardiac complications and were discharged 10 days after the procedure.Conclusions: This technique may be a good minimal invasive off-the-shelf technical option for aortic arch "debranching". More data and further improvements are required before this promising technique can be widely advocated. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Gross anatomical study of the aortic ARC branches of the paca (Agouti paca, Linnaeus, 1766)

Foi descrita a distribuição do arco aórtico de oito animais da espécie Agouti paca, sendo duas fêmeas adultas e seis filhotes jovens (3 machos e 3 fêmeas) que foram obtidos no Setor de Animais Silvestres da Faculdade de Ciências Agrárias e Veterinárias -- Campus de Jaboticabal. Após morte natural, seus vasos arteriais foram injetados com Neoprene latex 650 (Du Pont do Brasil S.A.) coloridos e colocados em uma solução de formalina a 10%. Depois de dissecados, notou-se que o arco aórtico desses animais emite a artéria subclávia e o tronco braquiocefálico. Este último dá origem à artéria carótida comum esquerda e a um tronco, do qual surgem a artéria carótida comum direita e a artéria subclávia direita. Estas emitem, em cada antímero, a artéria vertebral, a artéria tronco costocervical, a artéria cervical superficial, a artéria axilar e a artéria torácica interna. em apenas um animal a artéria carótida comum esquerda apresenta-se na forma de um sifão, logo após sua origem na artéria subclávia direita. Nos demais animais, a artéria carótida comum esquerda apresenta um trajeto retilíneo.

Arterite actínica de artéria subclávia: relato de caso e revisão de literatura

Diversas são as complicações possíveis da radioterapia na adjuvância do tratamento de neoplasias. Lesões actínicas de artéria subclávia em pacientes submetidos a este tipo de tratamento para neoplasia de mama são complicações conhecidas, porém com poucos relatos de casos publicados. No presente relato, descrevemos um caso de oclusão de artéria subclávia direita em paciente submetida à radioterapia para tratamento de neoplasia de mama, tratada com a revascularização convencional, com interposição de enxerto de politetrafluoretileno (PTFE). Na revisão da literatura realizada, foram encontrados doze casos descritos que evidenciaram diferentes opções terapêuticas. Concluímos que a arterite actínica de artéria subclávia é uma doença incomum, entretanto sua hipótese deve ser aventada em todos os pacientes com isquemia de membro superior já submetidos a tratamento de radioterapia.

Acesso pela artéria subclávia para implante por cateter da bioprótese valvar aórtica CoreValve®: dados do registro brasileiro

INTRODUÇÃO: A via de acesso transfemoral é preferencial para o implante por cateter de bioprótese valvar aórtica. Entretanto, algumas situações, como a presença de doença vascular periférica, impossibilitam a utilização desse acesso. Nesses casos, o acesso por dissecção da artéria subclávia é uma alternativa para a realização do procedimento. Nosso objetivo foi avaliar a experiência brasileira com a utilização da artéria subclávia como via de acesso para o implante por cateter da bioprótese CoreValve®. MÉTODOS: Foram requisitos para o procedimento área valvar aórtica < 1 cm², ânulo valvar aórtico ≥ 20 mm e ≤ 27 mm (CoreValve® de 26 mm e 29 mm), aorta ascendente ≤ 43 mm e artéria subclávia com diâmetro ≥ 6 mm, isenta de lesões obstrutivas significativas, tortuosidade acentuada e calcificação excessiva. O acesso pela artéria subclávia foi obtido por dissecção cirúrgica e, sob visão direta, punção da artéria subclávia. Obtido o acesso arterial, empregou-se a técnica padrão. RESULTADOS: Entre janeiro de 2008 e abril de 2012, 8 pacientes com doença vascular periférica foram submetidos a implante de prótese CoreValve® pela artéria subclávia em 4 instituições. O procedimento foi realizado com sucesso em todos os casos, com redução do gradiente transvalvar aórtico médio de 46,4 ± 17,5 mmHg para 9,3 ± 3,6 mmHg (P = 0,0018) e melhora dos sintomas. Aos 30 dias e no seguimento de 275 ± 231 dias, 87,5% e 62,5% dos pacientes, respectivamente, apresentavam-se livres de complicações maiores (óbito, infarto do miocárdio, acidente vascular cerebral e cirurgia cardíaca de urgência). CONCLUSÕES: Na experiência brasileira, o acesso pela artéria subclávia mostrou-se seguro e eficaz como via alternativa para o implante por cateter da bioprótese CoreValve®.

Preliminary results of an ICP-controlled subarachnoid hemorrhage rabbit model for the study of delayed cerebral vasospasm

INTRODUCTION: Intracisternal blood injection is the most common applied experimental subarachnoid bleeding technique in rabbits. The model comprises examiner-dependent variables and does not closely represent the human pathophysiological sequelae of ruptured cerebral aneurysm. The degree of achieved delayed cerebral vasospasm (DCVS) in this model is often mild. The aim of this study was to characterize and evaluate the feasibility of a clinically more relevant experimental SAH in vivo model. SAH was performed by arterial blood shunting from the subclavian artery into the great cerebral cistern. A total of five experiments were performed. Intracranial pressure (ICP), arterial blood pressure, heart rate, arterial blood gas analysis, and neurological status were monitored throughout the experiments. SAH induced vasoconstriction of the basilar artery was 52.1±3.4% on day 3 compared to baseline (P<0.05). Post-mortem gross examination of the brain showed massive blood clot accumulation around the brainstem and ventral surface of the brain. The novel technique offers an examiner independent SAH induction and triggers high degrees of delayed cerebral vasospasm. The severity of vasospasm attained offers a unique opportunity to evaluate future therapeutic treatment options.