Internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms

Background

An aorto-iliac aneurysm is a dilatation (aneurysm) of the aorta, the main large blood vessel in the body, which carries blood out from the heart to all organs and iliac arteries (distal branches of the aorta). The aneurysm can grow and burst (rupture), which leads to severe bleeding and is frequently fatal; an estimated 15,000 deaths occur each year from ruptured aortic abdominal aneurysms in the USA alone. To avoid this complication, the aorto-iliac aneurysm should be repaired when the maximum diameter of the aorta reaches 5 cm to 5.5 cm, or when the maximum diameter of the common iliac arteries reaches 3 cm to 4 cm.

Endovascular repair of aorto-iliac aneurysms is one approach that is used to manage this condition: a tube (stent-graft) is placed inside the aorto-iliac aneurysm, so that blood flows through the stent-graft and no longer into the aneurysm, excluding it from the circulation. To achieve a successful deployment of the stent-graft, a good seal zone (fixation zone) is needed in the aorta (proximal) and in the common iliac arteries (distal). However, in 40% of patients, the distal seal zone in the common iliac arteries is inadequate. In these cases, most commonly the stent-graft is extended to the external iliac artery and the internal iliac artery is blocked (occluded). However, this obstruction (occlusion) is not without harms: the internal iliac artery supplies blood to the pelvic organs (rectum, bladder, and reproductive organs) and the pelvic muscles, and occlusion is associated with complications in the pelvic area such as buttock claudication (cramping pain in the buttock during exercise), sexual dysfunction, and spinal cord injury.

New endovascular devices and techniques such as iliac branch devices have emerged to maintain blood flow into the internal iliac artery. These special stent-grafts position the distal seal zone within the external iliac artery, and a side branch of the graft allows for revascularisation of the internal iliac artery, while excluding the aneurysm from the circulation, promoting an adequate distal seal zone, and maintaining pelvic circulation. This may also preserve the quality of life of treated individuals and may reduce serious complications including spinal cord ischaemia, ischaemic colitis, and gluteal necrosis.

This review aimed to assess the effects of internal iliac artery revascularisation compared with internal iliac artery occlusion during endovascular repair of aorto-iliac aneurysms.

Study characteristics and key results

We searched for evidence that directly compared internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms. Our searches up to 28 August 2019 did not identify any randomised controlled trials (clinical studies in which people are randomly (by chance alone) put into one of several intervention groups) that met our criteria. Studies are needed to help vascular and endovascular surgeons choose the best option for endovascular repair of aorto‐iliac aneurysms and isolated iliac aneurysms with an inadequate distal fixation zone.

Conclusion

We found no RCTs that compared internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms. High-quality studies that evaluate the best strategy for managing the endovascular repair of aorto-iliac aneurysms with inadequate distal seal zones in the common iliac artery are needed.

Authors' conclusions: 

We found no RCTs that compared internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation. High-quality studies that evaluate the best strategy for managing endovascular repair of aorto-iliac aneurysms with inadequate distal seal zones in the common iliac artery are needed.

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Background: 

Endovascular aortic aneurysm repair (EVAR) is used to treat aorto-iliac and isolated iliac aneurysms in selected patients, and prospective studies have shown advantages compared with open surgical repair, mainly in the first years of follow-up. Although this technique produces good results, anatomic issues (such as common iliac artery ectasia or an aneurysm that involves the iliac bifurcation) can make EVAR more complex and challenging and can lead to an inadequate distal seal zone for the stent-graft. Inadequate distal fixation in the common iliac arteries can lead to a type Ib endoleak. To avoid this complication, one of the most commonly used techniques is unilateral or bilateral internal iliac artery occlusion and extension of the iliac limb stent-graft to the external iliac arteries with or without embolisation of the internal iliac artery. However, this occlusion is not without harm and is associated with ischaemic complications in the pelvic territory such as buttock claudication, sexual dysfunction, ischaemic colitis, gluteal necrosis, and spinal cord injury.

New endovascular devices and alternative techniques such as iliac branch devices and the sandwich technique have been described to maintain pelvic perfusion and decrease complications, achieving revascularisation of the internal iliac arteries in patients not suitable for an adequate seal zone in the common iliac arteries. These approaches may also preserve the quality of life of treated individuals and may decrease other serious complications including spinal cord ischaemia, ischaemic colitis, and gluteal necrosis, thereby decreasing the morbidity and mortality of EVAR.

Objectives: 

To assess the effects of internal iliac artery revascularisation versus internal iliac artery occlusion during endovascular repair of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation.

Search strategy: 

The Cochrane Vascular Information Specialists searched the Cochrane Vascular Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 28 August 2019. The review authors searched Latin American Caribbean Health Sciences Literature (LILACS) and the Indice Bibliográfico Español de Ciencias de la Salud (IBECS) on 28 August 2019 and contacted specialists in the field and manufacturers to identify relevant studies.

Selection criteria: 

We planned to include all randomised controlled trials (RCTs) that compared internal iliac artery revascularisation with internal iliac artery occlusion for patients undergoing endovascular treatment of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation.

Data collection and analysis: 

Two review authors independently assessed identified studies for potential inclusion in the review. We used standard methodological procedures in accordance with the Cochrane Handbook for Systematic Review of Interventions.

Main results: 

We identified no RCTs that met the inclusion criteria.

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