Fenestrated Endovascular Aneurysm Repair versus Snorkel Endovascular Aneurysm Repair: Competing yet Complementary Strategies

Monocentric Evaluation of Physician-Modified Fenestrations or Parallel Endografts for Complex Aortic Diseases

PURPOSE

This study aimed to investigate the demographic and anatomic characteristics, as well as perioperative and follow-up results of fenestration and parallel techniques for the endovascular repair of complex aortic diseases.

MATERIALS AND METHODS

A retrospective study was conducted on 67 consecutive patients underwent endovascular treatment for complex aortic diseases including abdominal aortic aneurysm (AAA), thoracoabdominal aneurysm (TAAA), aortic dissection, or prior endovascular repair with either fenestrated and parallel endovascular aortic repair (f-EVAR or ch-EVAR) at a single institute from 2013 to 2021. Choices of intervention were made by the disease' emergency, patients' general condition, the anatomic characteristics, as well as following the recommendation from the devices' guidelines. Patients' clinical demographics, aortic disease characteristics, perioperative details, and disease courses were discussed. Short- and mid-term follow-up results were obtained and analyzed. Endpoints were aneurysm-related and unrelated mortality, branch instability, and renal function deterioration.

RESULTS

Totally, 34 and 27 patients received f-EVAR and ch-EVAR, while 6 patients received a combination of both. Fenestrated endovascular aortic repair was conducted mainly in AAA affecting visceral branches and TAAA, whereas ch-EVAR was normally utilized for infrarenal AAA. Regarding the average number of reconstructed arteries per patient, there was a significant difference among f-EVAR, ch-EVAR, and the combination group (mean = 2.3 ± 0.9, 1.4 ± 0.6, 3.5 ± 0.5, p<0.001). Primary technical success was achieved in 28 (82.4%), 22 (81.5%), and 3 (50.0%) patients for each group. Besides operational time (5.77 ± 2.58, 4.47 ± 1.44, p=0.033), no significant difference was observed for blood transfusion, intensive care unit (ICU) or hospital stay, blood creatinine level, 30-day complications, or follow-up complications between patients undergoing f-EVAR or ch-EVAR. Patients receiving combination of both techniques had a higher rate of blood transfusion (p=0.044), longer operational time (p=0.008) or hospital stay (p=0.017), as well as more stent occlusion (p=0.001), endoleak (p=0.004) at short-term and a higher rate of endoleak (p=0.023) at mid-term follow-up.

CONCLUSION

In conclusion, this study demonstrated that f-EVAR and ch-EVAR techniques had acceptable perioperative and follow-up results and should be considered viable alternatives when encountering complex aortic diseases.

CLINICAL IMPACT

This study sought to investigate the baseline and pathological characteristics, as well as perioperative and follow-up results of f-EVAR and ch-EVAR at a single Chinese institution. F-EVAR (mostly physician-modified f-EVAR) was applied in patients with a wide range of etiologies and disease types, while ch-EVAR was preferred for AAA in older patients with an average higher ASA grade. Our experience suggested acceptable safety and efficacy both for techniques, and no significant difference was observed between the two groups regarding any short or mid-term adverse events.

Endovascular interventions in main renal artery pathologies: an overview and update

Renal arteries are involved in a wide spectrum of pathologies including atherosclerosis, fibromuscular dysplasia, Takayasu arteritis, aneurysms, and aortic type B dissections extending into main renal arteries. They manifest as renovascular hypertension, renal ischemia, and cardiovascular dysfunction. The location of the renal arteries in relation to the abdominal aortic aneurysm is a critical determinant of interventional options and long-term prognosis. This article provides a comprehensive review of the role of interventional radiologists in transcatheter interventions in various pathologies involving the main renal arteries with analysis of epidemiology, pathophysiology, newer interventional techniques, and management options.

Fenestrated Endovascular Aortic Repair With Chimney Graft for Thoracoabdominal Aneurysm

Thoracoabdominal aneurysms pose technical challenges for endovascular repair due to involvement of visceral and renal vessels. We report a case series of four patients diagnosed with thoracoabdominal aneurysm who underwent complex endovascular repair with Fenestrated Device and chimney grafts (FEVARCh). FEVARCh is a technically feasible approach for repair of thoracoabdominal aneurysms that involve renal, superior mesenteric, and celiac arteries for patients not appropriate for open surgical repair. Further studies are needed to understand the implications of resultant Type 1a endoleaks and strategies to minimize the displacement of the main body graft with adjunct chimneys.

Multicenter Mid-Term Outcomes of the Chimney Technique in the Elective Treatment of Degenerative Pararenal Aortic Aneurysms

PURPOSE

Chimney endovascular abdominal aortic aneurysm repair (CHEVAR) has predominantly been described as an alternative technique for the management of urgent presentations of degenerative pararenal aortic aneurysms (dPAAs). However, the role of CHEVAR in the treatment of asymptomatic patients remains unknown. The aim of current multinational study was to evaluate the outcomes of elective CHEVAR of dPAAs.

MATERIAL AND METHODS

Retrospective analysis of 267 consecutive dPAA patients treated with elective CHEVAR at 13 European and US centers from 2008 to 2014. Primary endpoints were 30 days and out of hospital CHEVAR-related mortality. Secondary endpoints included persistent type Ia endoleak or endotension, angiographically confirmed occlusion and/or high-grade chimney graft (CG) or involved splanchnic vessel stenosis identified at index procedure and/or during follow-up, as well as CHEVAR-related re-intervention.

RESULTS

Mean follow-up time was 25.5±13.3 months. The 442 visceral vessels were involved and mean number of CGs per patient was 1.63±0.7. 436 targeted vessels were successfully cannulated. The aortic graft intentionally covered 6 renal arteries and immediate technical success was 98.6%. The 30 days mortality was 1.9% (n=5), while the in-hospital complication rate was 10.1% (n=27) including 3 strokes, 1 permanent dialysis, and 1 intestinal ischemia. No 30 day type Ia endoleaks were detected and 3.2% of CGs (n=14, including the intentionally covered) had evidence of occlusion and/or stenosis. The overall CHEVAR-related mortality was 2.2% (n=6). Freedom from primary and secondary type Ia endoleak/endotension rates at 3 years was 93.0% and 98.0%, respectively. Primary and secondary CG patency was 87.0% and 89.0%. Primary and secondary endovascular freedom from any endpoint at 3 years was 81.0% and 94.0% respectively.

CONCLUSION

Elective use of CHEVAR in the management of dPAAs seems to be durable. These results are comparable to published outcomes with other total endovascular strategies, which justifies an expanded role for CHEVAR in the treatment of asymptomatic patients presenting with dPAAs.

Funnel technique for wide infrarenal aneurysm neck with Lifetech Ankura™ Stent Graft System

Background

In this study, we present our mid-term results in patients undergoing treatment with the funnel technique and describe technical issues for this bailout technique in extra-wide infrarenal necks.

Methods

Between January 2018 and June 2020, a total of seven male, symptomatic patients (median: 74.5 years; range, 64 to 84 years) who had comorbidities and were in the American Society for Anesthesiologists Class IV and treated by the funnel technique in an endovascular fashion were included. Pre- and post-procedural data of the patients, early mortality and technical success rates were evaluated.

Results

There was no early mortality. Technical success rate was 100%. There was no type I or III endoleaks at the completion angiography. All patients were discharged without any problem on the second or third day of the procedure. The median follow-up was 13 (range, 6 to 28) months. The aneurysm sac shrinkage was achieved in all patients over six months of follow up. During the follow-up period, no proximal endoleak or infrarenal aortic neck diameter enlargement was found.

Conclusion

Based on our limited experience, the funnel technique may be considered more than a bailout procedure under special circumstances.

Current assessment and management of endoleaks after advanced EVAR: new devices, new endoleaks?

INTRODUCTION

In recent years there has been an increasing application of advanced EVAR techniques to tackle complex clinical and anatomical scenarios. In a bid to overcome the limitations of the traditional stent-grafts, newer EVAR endografts and techniques have been developed and introduced into clinical practice, permitting endovascular management of difficult infrarenal, juxta-renal and thoracoabdominal aneurysms for which previously there was no endovascular solution. As a consequence, we are now confronted with unique patterns of endoleak requiring customized clinical-radiological assessment and treatment. Despite the increasing body of evidence regarding new EVAR techniques and related endoleaks, current guidelines do not specifically address these issues.

OBJECTIVES

Our review aims to assess risk factors, development, and management strategies of these endoleaks, in the most recent infrarenal EVAR devices and in more complex fenestrated EVAR (FEVAR) and Chimney EVAR (Ch-EVAR).

EXPERT OPINION

Most new devices have demonstrated types of endoleaks that need specific imaging and treatment, as in EVAS, FEVAR, and ChEVAR. Knowledge of specific stent-graft characteristics and the nature of endoleaks associated with the various procedures facilitates the application of relevant useful imaging. In addition, it should aid development of a customized and practically relevant approach to patient management during intervention and follow-up.

Thrombogenic and Inflammatory Reactions to Biomaterials in Medical Devices

Blood-contacting medical devices of different biomaterials are often used to treat various cardiovascular diseases. Thrombus formation is a common cause of failure of cardiovascular devices. Currently, there are no clinically available biomaterials that can totally inhibit thrombosis under the more challenging environments (e.g., low flow in the venous system). Although some biomaterials reduce protein adsorption or cell adhesion, the issue of biomaterial associated with thrombosis and inflammation still exists. To better understand how to develop more thrombosis-resistant medical devices, it is essential to understand the biology and mechano-transduction of thrombus nucleation and progression. In this review, we will compare the mechanisms of thrombus development and progression in the arterial and venous systems. We will address various aspects of thrombosis, starting with biology of thrombosis, mathematical modeling to integrate the mechanism of thrombosis, and thrombus formation on medical devices. Prevention of these problems requires a multifaceted approach that involves more effective and safer thrombolytic agents but more importantly the development of novel thrombosis-resistant biomaterials mimicking the biological characteristics of the endothelium and extracellular matrix tissues that also ameliorate the development and the progression of chronic inflammation as part of the processes associated with the detrimental generation of late thrombosis and neo-atherosclerosis. Until such developments occur, engineers and clinicians must work together to develop devices that require minimal anticoagulants and thrombolytics to mitigate thrombosis and inflammation without causing serious bleeding side effects.