Stent graft types for endovascular repair of abdominal aortic aneurysms

TEVAR and EVAR, the unknown knowns of the cardiovascular hemodynamics; and the immediate and long-term consequences of fabric material on major adverse clinical outcome

This review discusses the impact of endovascular aneurysm repair on cardiovascular (CV) hemodynamics and the role of stent-graft material, i.e., polytetrafluoroethylene (PTFE) vs. polyester in post-procedural outcomes. Endovascular aneurysm repair has been widely employed in the last decades for thoracic and abdominal aneurysm repair. However, aortic endografts are stiff and alter the native flow hemodynamics. This failure to simulate the native aorta could lead to added strain on the heart, manifesting as increased left ventricular strain, higher pulse pressure, and congestive heart failure later. This could result in adverse CV outcomes. Also, evidence is mounting to support the implication of stent-graft materials, i.e., PTFE vs. polyester, in adverse post-procedural outcomes. However, there is an absence of level one evidence. Therefore, the only way forward is to plan and perform a randomised controlled trial to demonstrate the alterations in the CV hemodynamics in the short and long run and compare the available stent-graft materials regarding procedural and clinical outcomes. We believe the best solution, for now, would be to reduce the stented length of the aorta. At the same time, in the longer term, encourage continuous improvement in stent-graft materials and design.

Editor's Choice - Renal complications after EVAR with suprarenal versus infrarenal fixation among all users and routine users

BACKGROUND

Previous studies comparing endografts with suprarenal and infrarenal fixation for endovascular abdominal aortic aneurysm repair (EVAR) have found conflicting results and did not account for differences in patient selection. This study aims to evaluate the differences in outcomes among surgeons who routinely use either suprarenal or infrarenal fixation, as well as all surgeons in the Vascular Study Group of New England (VSGNE).

METHODS

All patients undergoing EVAR in the VSGNE from 2003 to 2014 were identified. All ruptured aneurysms, repairs with concomitant procedures, and infrequently used stent grafts (<50) were excluded. Suprarenal endografts included Talent, Zenith, and Endurant; infrarenal endografts included AneuRx and Excluder. Grafts were compared among surgeons who used only one type of endograft (suprarenal or infrarenal) for >80% of cases, as well as all surgeons. Multivariate regression and Cox hazard models were utilised to account for patient demographics, comorbidities, operative differences, and procedure year.

RESULTS

This study identified 2574 patients (suprarenal, 1264; infrarenal, 1310) with 888 endografts placed by routine users (suprarenal, 409; infrarenal, 479). There were no differences in baseline comorbidities, including the estimated glomerular filtration rate, between suprarenal and infrarenal fixation, or between patients with endografts placed by routine and non-routine users. Patients treated with suprarenal endografts received more contrast than all users (102 mL vs. 100 mL, p = .01) and routine users (110 mL vs. 88 mL, p < .01), but other vascular and operative details were similar. Among all users, patients treated with suprarenal grafts had higher rates of creatinine increase >.5 mg/dL (3.7% vs. 2.0%, p = .01), length of stay >2 days (27% vs. 19%, p < .01), and discharge to a skilled nursing facility (9.2% vs. 6.7%, p = .02). There were no differences in 30 day or 1 year mortality. Following adjustment, suprarenal stent grafts remained associated with an increased risk of renal deterioration (OR 2.0; 95% CI 1.2-3.4) and prolonged length of stay (OR 1.8; 95% CI 1.4-2.2). Among routine users, suprarenal fixation was also associated with higher rates of renal dysfunction (3.7% vs. 1.3%, p = .02; OR 2.9; 95% CI 1.1-7.8).

CONCLUSION

Despite potential differences in patient selection, endografts with suprarenal fixation among all users and routine users were associated with higher rates of renal deterioration and longer length of hospital stay. Longer-term data are needed to determine the duration and severity of renal function decline and to identify potential benefits of decreased migration or endoleak.

Stent graft types for endovascular repair of thoracic aortic aneurysms

BACKGROUND

The UK prevalence of thoracic aneurysm is estimated at 10.4 per 100,000 person-years. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of thoracic aortic aneurysms involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market. This is an update of the review first published in 2013.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of thoracic aortic aneurysms.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2015) and the Cochrane Register of Studies CENTRAL (2015, Issue 1). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of thoracic aortic aneurysms were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria. It was not possible to assess the quality of the evidence in the absence of studies eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. High quality RCTs evaluating stent graft types in thoracic endovascular aneurysm repair are required.