Branched and fenestrated endovascular aortic arch repair in patients with native proximal aortic landing zone

OBJECTIVE

Fenestrated and branched thoracic endovascular repair (f/bTEVAR) have been successfully applied in patients with diverse aortic arch pathologies. The aim of this study is to present the early and mid-term outcomes of patients with native proximal aortic landing (NPAL) managed with f/bTEVAR.

METHODS

A single-center retrospective analysis of patients with NPAL, managed with f/bTEVAR, between September 1, 2011, and June 30, 2022, was conducted. All patients were treated with custom-made devices (Cook Medical) with landing within Ishimaru zones 0 to 2. Primary outcomes were technical success, mortality, stroke, and retrograde type A dissection at 30 days. Follow-up outcomes were considered secondary.

RESULTS

A total of 126 patients were included (69.8% males; mean age, 70.8 ± 4.2 years; 18.3% urgent). The main indications (60.4%) for repair were aortic arch (29.4%) and thoracoabdominal aortic aneurysms (31.0%). Seventy-two patients (57.1%) were managed with fTEVAR. Proximal landing in zone 0 and 1 was chosen in 97.6%. Technical success was 94.4%, and 30-day mortality was 11.9%. Strokes were diagnosed in 13.5% of patients and major strokes were identified in 7.9% cases. Retrograde type A dissection rate was 3.9%. The multivariate analysis confirmed landing in Ishimaru zone 0 as an independently related factor for stroke (P = .005), whereas stroke (P < .001), pericardial effusion (P < .001), and acute kidney injury (P < .001) were independently related to 30-day mortality. Mean follow-up was 17.5 ± 9.3 months. The estimated survival rate and the freedom from reintervention rate were 72.6% (standard error, 4.4%) and 46.4% (standard error, 6.0%) at 24-month follow-up, respectively.

CONCLUSIONS

Stroke rate after endovascular arch repair was alarming among patients with NPAL. Proximal landing to zone 0 was related to higher risk of stroke. Reinterventions were common within the 24-month follow-up.

Endovascular reconstruction of the aortic arch with new-generation dual-branch and triple-branch endograft: design, applicability, indications, outcomes, and future directions

INTRODUCTION

Repair of aortic arch pathologies such as degenerative aneurysms and dissections still represents a significant challenge for vascular and cardiac surgeons. We focused on the design, evolution, implementation, and prospects of endovascular dual branch technology for treatment of pathologies in the aortic arch.

AREAS COVERED

The literature search was conducted in a non-systematic fashion through the PubMed and Scopus databases; articles deemed relevant to the scope of the work and fully published in English language from January 12,000 until December 2023 were considered for inclusion. Two companies so far have developed and launched in market a dedicated arch dual branch platform: Terumo Aortic and Cook Medical.

EXPERT OPINION

A common limitation to the available technology is represented by the fact that urgent cases (i.e. large or rapidly growing aneurysms, symptomatic patients) cannot be treated because the customization process generally takes between 6 and 8 weeks, and there is an inherent risk for aorta-related adverse events to happen during the waiting time. While the future holds much promise, several technical hurdles still exist and further developments (in device design, operators' skills, patients' selection, and outcomes assessment) are needed to establish the safety and effectiveness of treatment particularly over the long-run.

The impact of increasing saline flush volume to reduce the amount of residual air in the delivery system of aortic prostheses-a randomized controlled trial

Background

Air embolism is a known risk during thoracic endovascular aortic repair (TEVAR) and is associated with an incomplete deairing of the delivery system despite the saline lavage recommended by the instructions for use (IFU). As the delivery systems are identical and residual air remains frequently in the abdominal aortic aneurysm sac, endovascular aortic repair (EVAR) can be used to examine the effectiveness of deairing maneuvers. We aimed to evaluate whether increasing the flush volume can result in a more complete deairing.

Methods

Patients undergoing EVAR were randomly assigned according to flushing volume (Group A, 1× IFU; Group B, 4× IFU). The Terumo Aortic Anaconda and Treo and Cook Zenith Alpha Abdominal stent grafts were randomly implanted in equal distribution (10-10-10). The quantity of air trapped in the aneurysm sac was measured using a pre-discharge computed tomography angiography (CTA). Thirty patients were enrolled and equally distributed between the two groups, with no differences observed in any demographic or anatomical factors.

Results

The presence of air was less frequent in Group A compared to that in Group B [7 (47%) vs. 13 (87%), p = .02], and the air volume was less in Group A compared to that in Group B (103.5 ± 210.4 vs. 175.5 ± 175.0 mm3, p = .04). Additionally, the volume of trapped air was higher with the Anaconda graft type (p = .025).

Discussion

These findings suggest that increased flushing volume is associated with a higher amount of trapped air; thus, following the IFU might be associated with a reduced risk of air embolization. Furthermore, significant differences were identified between devices in terms of the amount of trapped air.

Clinical trial registration

[NCT04909190], [ClinicalTrials.gov].

Iatrogenic Air Embolisms During Endovascular Interventions: Impact of Origin and Number of Air Bubbles on Cerebral Infarctions

PURPOSE

Cerebral infarctions caused by air embolisms (AE) are a feared risk in endovascular procedures; however, the relevance and pathophysiology of these AEs is still largely unclear. The objective of this study was to investigate the impact of the origin (aorta, carotid artery or right atrium) and number of air bubbles on cerebral infarctions in an experimental in vivo model.

METHODS

In 20 rats 1200 or 2000 highly calibrated micro air bubbles (MAB) with a size of 85 µm were injected at the aortic valve (group Ao), into the common carotid artery (group CA) or into the right atrium (group RA) using a microcatheter via a transfemoral access, resembling endovascular interventions in humans. Magnetic resonance imaging (MRI) using a 9.4T system was performed 1 h after MAB injection followed by finalization.

RESULTS

The number (5.5 vs. 5.5 median) and embolic patterns of infarctions did not significantly differ between groups Ao and CA. The number of infarctions were significantly higher comparing 2000 and 1200 injected MABs (6 vs. 4.5; p < 0.001). The infarctions were significantly larger for group CA (median infarction volume: 0.41 mm3 vs. 0.19 mm3; p < 0.001). In group RA and in the control group no infarctions were detected. Histopathological analyses showed early signs of ischemic stroke.

CONCLUSION

Iatrogenic AEs originating at the ascending aorta cause a similar number and pattern of cerebral infarctions compared to those with origin at the carotid artery. These findings underline the relevance and potential risk of AE occurring during endovascular interventions at the aortic valve and ascending aorta.

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Iatrogenic air embolism: influence of air bubble size on cerebral infarctions in an experimental in vivo and numerical simulation model

BACKGROUND

Cerebral infarctions resulting from iatrogenic air embolism (AE), mainly caused by small air bubbles, are a well-known and often overlooked event in endovascular interventions. Despite their significance, the underlying pathophysiology remains largely unclear.

METHODS

In 24 rats, AEs were induced using a microcatheter, positioned in the carotid artery via femoral access. Rats were divided into two study groups, based on the size of the bubbles (85 and 120 µm) and two sub-groups, differing in air volume (0.39 and 0.64 µl). Ultra-high-field magnetic resonance imaging (MRI) was performed 1.5 hours after intervention. MRI findings including the number, single volume and total volume of the infarctions were assessed. A software-based numerical simulation was performed to qualitatively assess the microvascular pathomechanisms.

RESULTS

In the study groups 22 of 24 rats (92%) revealed cerebral infarctions. The number of infarctions per rat was higher for the smaller bubbles, for the lower (medians: 5 vs 3; p=0.049) and higher air volume sub-groups (medians: 6 vs 4; p=0.012). Correspondingly, total infarction volume was higher for the smaller bubbles (1.67 vs 0.5 mm³; p=0.042). Simulations confirmed the results of the experiments and suggested that fusion of microbubbles to larger bubbles is the underlying pathomechanism of vascular occlusions.

CONCLUSION

In iatrogenic AE, the size of the bubbles can have a major impact on the number and total volume of cerebral infarctions. These findings can help to better understand the pathophysiology of this frequent, often underestimated adverse event in endovascular interventions.

Avoiding Stroke in Patients Undergoing Endovascular Aortic Arch Repair: JACC Review Topic of the Week

As the bottleneck of endovascular aortic arch repair, early postoperative stroke remains a devastating complication in high-risk patients and a critical concern for the development of optimal endovascular techniques and devices. The incidence of early postoperative stroke varies widely among currently available endovascular techniques and devices, with reported rates ranging from 0.0% to 42.9%, and is significantly influenced by the severity of the patient's preexisting aortic atherosclerotic burden, air released from the endovascular device, and a variety of factors leading to cerebral perfusion insufficiency. Currently, preidentification of high-risk patients and careful perioperative management appear to play a critical role in reducing stroke incidence. Specific intraoperative prevention methods are still lacking, but embolic protection devices and carbon dioxide or high-volume saline flushing of endovascular devices appear promising. Detailed preoperative stroke risk stratification and screening for optimal endovascular techniques and devices for aortic arch treatment are unmet clinical needs.

Endovascular Options for the Ascending Aorta and Aortic Arch - A Scoping Review

The gold standard for aneurysmal repair of the ascending aorta and the aortic arch has been open surgery with an established track record of good results in suitable patients. In recent years, with innovations in the endovascular field alternative endovascular solutions for pathologies of the aortic arch and ascending aorta became available. At first reserved only for highly selected patients unfit for open surgery, endovascular aortic arch repair is now being offered to patients with suitable anatomy in high volume referral centers after discussion in an interdisciplinary team. The present scoping review aims at providing an overview on indications, available devices, technical aspects and feasibility studies of endovascular arch repair both in elective and emergent situations, including also experiences and considerations from our center.

Investigation of Experimental Endovascular Air Embolisms Using a New Model for the Generation and Detection of Highly Calibrated Micro Air Bubbles

BACKGROUND

Air embolism (AE), especially when affecting the brain, is an underrated and potentially life-threatening complication in various endovascular interventions. This study aims to investigate experimental AEs using a new model to generate micro air bubbles (MAB), to assess the impact of a catheter on these MAB, and to demonstrate the applicability of this model in vivo.

MATERIALS AND METHODS

Micro air bubbles were created using a system based on microfluidic channels. The MAB were detected and analyzed automatically. Micro air bubbles, with a target size of 85 µm, were generated and injected through a microcatheter. The MAB diameters proximal and distal to the catheter were assessed and compared. In a subsequent in vivo application, 2000 MAB were injected into the aorta (at the aortic valve) and into the common carotid artery (CCA) of a rat, respectively, using a microcatheter, resembling AE occurring during cardiovascular interventions.

RESULTS

Micro air bubbles with a highly calibrated size could be successfully generated (median: 85.5 µm, SD 1.9 µm). After passage of the microcatheter, the MAB were similar in diameter (median: 86.6 µm) but at a lower number (60.1% of the injected MAB) and a substantially higher scattering of diameters (SD 29.6 µm). In vivo injection of MAB into the aorta resulted in cerebral microinfarctions in both hemispheres, whereas injection into the CCA caused exclusively ipsilateral microinfarctions.

CONCLUSION

Using this new AE model, MAB can be generated precisely and reproducibly, resulting in cerebral microinfarctions. This model is feasible for further studies on the pathophysiology and prevention of AE in cardiovascular procedures.

Modular Endo-Bentall Procedure Using a "Rendez-Vous Access"

PURPOSE

The concept of a single endovascular valve-carrying conduit device was designated endo-Bentall, but published experience is limited to a single case. This technical note describes an alternative modular endo-Bentall technique and a novel access technique to implant it.

TECHNIQUE

A 82-year-old woman with chest pain referred for a 10 cm symptomatic aneurysm of the distal arch and descending aorta. An ascending aortic aneurysm of 5.5 cm prevented endovascular aortic arch repair due to lack of a proximal landing zone. The technique is a modular approach combining a physician-modified endograft (PMEG) with 3 large fenestrations for coronary artery perfusion and a transcatheter aortic valve implantation (TAVI). A "rendez-vous access" with a transapical and transfemoral through-and-through wire offered rapid sequential deployment in a modular fashion of both components. The PMEG was deployed first, landing 5 mm deep in the left ventricular outflow tract (LVOT) and the transcatheter aortic valve was implanted few millimeters below. The endo-Bentall procedure was combined with endovascular aortic arch repair.

CONCLUSION

A modular endo-Bentall procedure combining a PMEG and TAVI is feasible and adaptable to emergent setting using the "rendez-vous access."

Actual incidence of cerebral infarction after thoracic endovascular aortic repair: a magnetic resonance imaging study

 

OBJECTIVES

The actual incidence of cerebral infarction (CI), including asymptomatic infarction, owing to thoracic endovascular aortic repair (TEVAR) has not been reported in detail. This study was performed to investigate the incidence of post-TEVAR CI by using diffusion-weighted magnetic resonance imaging (DW-MRI) and to determine the risk factors for both symptomatic and asymptomatic CI.

METHODS

We examined 64 patients undergoing TEVAR at our institute between April 2017 and November 2020. Aortic atheroma was graded from 1 to 5 by preoperative computed tomography. Cerebral DW-MRIs were conducted 2 days after the procedure to diagnose postoperative CI.

RESULTS

A total of 44 new foci were detected by post-interventional cerebral DW-MRI in 22 patients (34.4%). Only one patient developed a symptomatic stroke (1.6%), and TEVAR was successfully completed in all cases. Debranching of the aortic arch and left subclavian artery occlusion with a vascular plug was performed in 19 (29.7%) and 12 (18.8%) patients, respectively. The number of patients with proximal landing zones 0–2 was significantly higher in the CI group than in the non-CI group (68.2% vs 11.9%; P < 0.001). The following risk factors were identified for asymptomatic CI: aortic arch debranching (P < 0.001), left subclavian artery occlusion (P = 0.001) and grade 4/5 aortic arch atheroma (P = 0.048).

CONCLUSIONS

Over one-third of the patients examined by cerebral DW-MRI after TEVAR were diagnosed with CI. High-grade atheroma and TEVAR landing in zone 0–2 were found to be positively associated with asymptomatic CI.

Clinical trial registration

02-014.

Narrative review on endovascular techniques for left subclavian artery revascularization during thoracic endovascular aortic repair and risk factors for postoperative stroke

OBJECTIVES

The aim of this study was to present a narrative review on endovascular techniques (ET) for revascularization of the left subclavian artery (LSA) during zone 2 thoracic endovascular aortic repair (TEVAR) and on risk factors for postoperative stroke following TEVAR procedures.

METHODS

Non-systematic search of the literature from the PubMed, Ovid and Scopus databases to identify relevant English-language articles fully published in the period 1 January 2010-1 August 2020.

RESULTS

Current general agreement is that LSA revascularization should be always attempted in the elective setting. Under urgent circumstances, it can be delayed but might be considered during the same session on a case-by-case basis. Three ET are currently available: (i) chimney/snorkels (also known as parallel grafts), (ii) fenestrations or branches and (iii) proximal scallops. The main issue with ET is the potential for increased peri-operative stroke risk owing to increased manipulation within the aortic arch. Also, they are relatively novel and further assessment of their long-term durability is needed. Intra-operative embolism and loss of left vertebral artery perfusion are hypothesized as the main causes of stroke in patients undergoing TEVAR.

CONCLUSIONS

The overall risk of stroke seems higher without LSA revascularization during zone 2 TEVAR. As LSA revascularization might have a direct effect in preventing posterior stroke, it should be routinely performed in elective cases, while a case-by-case evaluation can be made under urgent circumstances. While ET can provide effective options for LSA revascularization during zone 2 TEVAR, they are novel and need further durability assessment. Stroke after TEVAR is a multifactorial pathological process and preventing TEVAR-related cerebral injury remains a significant unmet clinical need.

Silent Brain Infarction After Endovascular Arch Procedures: Preliminary Results from the STEP Registry

OBJECTIVE

Few data exist concerning the rate of silent cerebral ischaemic events following endovascular treatment of the aortic arch. The objective of this work was to quantify these lesions using the STEP registry (NCT04489277).

METHODS

This multicentre retrospective cohort study included consecutive patients treated with an aortic endoprosthesis deployed in Ishimaru zone 0-3 and brain diffusion weighted magnetic resonance imaging (DW-MRI) within seven days following the procedure. DW-MRI was performed to identify the location and number of new silent brain infarctions (SBI). All endografts were carbon dioxide flushed prior to implantation.

RESULTS

The study population included 91 patients (mean age, 69 years; men, 64%) from two academic centres treated between September 2018 and January 2020. The procedure was elective in 71 patients (78%). The treatment was performed for a dissection, degenerative aneurysm, or other aortic disease in 44 (49%), 34 (37%), and 13 (14%) patients, respectively. Endografts were deployed in zone 0, 1, 2 or 3 in 23 (25%), 10 (11%), 47 (52%), and 11 (12%) patients, respectively. Endografts were branched (25%), fenestrated (17%), or tubular (58%). At 30 days, there were no deaths or clinical strokes. On cerebral DW-MRI, a total of 245 SBI were identified in 45 patients (50%). Lesions were in the left hemisphere in 63% of the patients (153/245), predominantly in the middle territory (94/245). Deployment in zone 0-1 (p = .026), placement of a branched or fenestrated endograft (p = .038), a proximal endoprosthesis diameter ≥ 40 mm (p = .038), and an urgent procedure (p = .005) were significantly associated with the presence of SBI on univariable analysis, while urgent procedure was found to be an independent predictor on multivariable analysis (binary logistic regression) (p = .002).

CONCLUSION

SBI following endovascular repair of the aortic arch is frequent, although there were no clinical strokes. Innovative strategies to reduce the risk of embolisation need to be developed.

Aneurysms and dissections - What is new in the literature of 2019/2020 - a European Society of Vascular Medicine annual review

More than 6,000 publications were found in PubMed concerning aneurysms and dissections, including those Epub ahead of print in 2019, printed in 2020. Among those publications 327 were selected and considered of particular interest.

Brain Protection in the Endo-Management of Proximal Aortic Aneurysms

Neurological brain injury (NBI) remains the most feared complication following thoracic endovascular aortic repair (TEVAR), and can manifest as clinically overt stroke and/or more covert injury, detected only on explicit neuropsychological testing. Microembolic signals (MES) detected on transcranial Doppler (TCD) monitoring of the cerebral arteries during TEVAR and the high prevalence and incidence of new ischaemic infarcts on diffusion-weighted magnetic resonance imaging (DW-MRI) suggests procedure-related solid and gaseous cerebral microembolisation to be an important cause of NBI. Any intervention that can reduce the embolic burden during TEVAR may, therefore, help mitigate the risk of stroke and the covert impact of ischaemic infarcts to the function of the brain. This perspective article provides an understanding of the mechanism of stroke and reviews the available evidence regarding potential neuroprotective strategies that target high-risk procedural steps of TEVAR to reduce periprocedural cerebral embolisation.

Role of Endoluminal Techniques in the Management of Chronic Type B Aortic Dissection

In recent guidelines of international societies, the most frequent indication for treatment after chronic type B aortic dissection (cTBAD) is aneurysmal dilatation. Endovascular repair is recommended in patients with moderate to high surgical risk or with contraindications to open repair. During the last decade, many advances have been made in the field of endovascular techniques and devices. The aim of this article is to address the current status of endoluminal techniques for the management of cTBAD including standard thoracic endovascular repair, new devices, fenestrated and branched abdominal aortic devices and false lumen occlusion techniques.