Effectiveness of angioplasty compared with stenting in atherosclerotic disease of the iliac arteries

Background

Atherosclerosis in the iliac artery (main pelvic artery towards the leg) may result in narrowing or obstruction (occlusion), leading to reduced blood flow to the leg. This is called iliac artery occlusive disease. Iliac artery occlusive disease may lead to symptoms of pain in the legs when walking (intermittent claudication), pain at rest, or ulcers of the foot or leg. A range of surgical and endovascular (from inside the artery, e.g. angioplasty) treatment options are available. Open surgical procedures have excellent patency rates (percentage of the vessels that remain open) but at the cost of substantial illness and death. Endovascular treatment has good safety and short-term effectiveness with decreased illness, complications and costs compared with open surgical procedures. Percutaneous transluminal angioplasty (PTA; dilation of the artery with a balloon) and stenting (insertion of a small mesh tube) are widely used endovascular treatment options for iliac artery occlusive disease. A narrowing or obstruction of the iliac artery can be treated successfully by PTA alone. If PTA alone is not successful, an additional stent can be placed. Alternatively, a stent could be placed on its own to treat an iliac narrowing or obstruction (this is called primary stenting (PS)). However, there is limited evidence to prove which endovascular treatment strategy is better for lesions that restrict the iliac arteries. This review investigates whether it is better to place a stent in the first instance, or only under particular circumstances.

Study characteristics and key results

We found no new studies for this update. Previously, we had identified two studies with a combined total of 397 participants relevant to this topic. Combining the data was not possible due to the differences between the two included studies. The evidence in this Cochrane Review is current to 24 September 2019.

For the following outcomes of interest, no clear differences emerged between the two types of treatment: technical success of the procedure, improvement in the severity of the arterial occlusive disease, or patency of the treated vessel. However, in one study, which only included iliac artery occlusions, fewer complications were observed in the group of participants treated with PS. Neither study reported on delayed complications. One study reported on reintervention, and resolution of symptoms and signs, with no evidence of a difference detected between the PS group and the PTA group. Neither study reported on improvement in walking distance. More research on this subject is necessary.

Reliability of the evidence

Both studies had some risk of bias relating to selective reporting and non-blinding of participants and personnel. Both studies occurred in the 1990s and techniques have since evolved. We considered the overall certainty of the evidence to be low due to this risk of bias, the small number of included studies and the differences in the types of patients that were included.

Authors' conclusions: 

There is insufficient evidence to make general conclusions about the effects of percutaneous transluminal angioplasty versus primary stenting for stenotic and occlusive lesions of the iliac artery. Data from one study indicate that primary stenting in iliac artery occlusions may result in lower distal embolisation rates (low certainty evidence). The evidence in this review, based on two studies, was assessed as low certainty, with downgrading decisions based on limitations in risk of bias, imprecision and indirectness. More studies are required to strengthen our confidence in the results.

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Background: 

Atherosclerosis of the iliac artery may result in a stenosis or occlusion, which is defined as iliac artery occlusive disease. A range of surgical and endovascular treatment options are available. Open surgical procedures have excellent patency rates but at the cost of substantial morbidity and mortality. Endovascular treatment has good safety and short-term efficacy with decreased morbidity, complications and costs compared with open surgical procedures. Both percutaneous transluminal angioplasty (PTA) and stenting are commonly used endovascular treatment options for iliac artery occlusive disease. A stenotic or occlusive lesion of the iliac artery can be treated successfully by PTA alone. If PTA alone is technically unsuccessful, additional stent placement is indicated. Alternatively, a stent could be placed primarily to treat an iliac artery stenosis or occlusion (primary stenting, PS). However, there is limited evidence to prove which endovascular treatment strategy is superior for stenotic and occlusive lesions of the iliac arteries. This is an update of the review first published in 2015.

Objectives: 

To assess the effects of percutaneous transluminal angioplasty versus primary stenting for stenotic and occlusive lesions of the iliac artery.

Search strategy: 

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 24 September 2019. We also undertook reference checking and citation searching to identify additional studies.

Selection criteria: 

We included all randomised controlled trials (RCTs) comparing percutaneous transluminal angioplasty and primary stenting for iliac artery occlusive disease. We excluded quasi-randomised trials, case reports, case-control or cohort studies. We did not exclude studies based on the language of publication.

Data collection and analysis: 

Two authors independently selected suitable trials, extracted data, assessed trial quality and performed data analyses. When there was disagreement, consensus would be reached first by discussion between the two authors and, if needed, through consultation with a third author. We used GRADE criteria to assess the certainty of the evidence and presented the main results in a 'Summary of findings' table. The main outcomes of interest were technical success, complications, symptomatic improvement of peripheral arterial disease (PAD), patency, reinterventions, resolutions of symptoms and signs, and improvement in walking distance as reported by the patient.

Main results: 

We identified no new studies for this update. Previously, we identified two RCTs, with a combined total of 397 participants, as meeting the selection criteria. One study included mostly stenotic lesions (95%), whereas the second study included only iliac artery occlusions. Heterogeneity between these two studies meant it was not possible to pool the data. Both studies were of moderate methodological quality with some risk of bias relating to selective reporting and non-blinding of participants and personnel. Both studies occurred in the 1990s and techniques have since evolved. We assessed the overall certainty of the evidence to be low. We downgraded by two levels: one for risk of bias concerns and one for imprecision and indirectness.

There was no evidence of a difference following percutaneous transluminal angioplasty (PTA) with selective stenting compared to primary stenting (PS) in technical success rates in either the study involving stenotic lesions (odds ratio (OR) 1.51, 95% confidence interval (CI) 0.77 to 2.99; 279 participants; low certainty evidence); or the study involving iliac artery occlusions (OR 2.95, 95% CI 0.12 to 73.90; 112 participants; low certainty evidence). In one trial, PTA of iliac artery occlusions resulted in a higher rate of major complications, especially distal embolisation (OR 4.50 95% CI 1.18 to 17.14; 1 study, 112 participants; low certainty evidence). Immediate complications were similar in the second study (OR 1.81, 95% CI 0.64 to 5.13; 1 study, 279 participants; low certainty evidence). Neither study reported on delayed complications. No evidence of a difference was seen in symptomatic improvement (OR 1.03, 95% CI 0.47 to 2.27; 1 study, 157 participants; low certainty evidence). The second study did not provide data but reported no differences. For the outcome of patency, no evidence of a difference was seen in the study involving iliac occlusion at two years (OR 1.60, 95% CI 0.34 to 7.44; 1 study, 57 participants; low certainty evidence); or the study involving stenotic lesions at two years (71.3% in the PS group versus 69.9% in the PTA group). Only one study reported on reintervention (six to eight years, OR 1.22, 95% CI 0.67 to 2.23; 1 study, 279 participants; low certainty evidence); and resolution of symptoms and signs (12 months, OR 1.14, 95% CI 0.65 to 2.00; 1 study, 219 participants; low certainty evidence), with no evidence of a difference detected in either outcome. Neither study reported on improvement in walking distance as reported by the patient.

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