Uncoated balloon angioplasty versus drug-eluting balloon angioplasty for peripheral arterial disease of the lower limbs

Background

Peripheral arterial disease (PAD) of the lower limbs is a widespread condition that affects many people. In its advanced form, PAD can lead to pain, infections, and amputation. People with PAD are usually first treated with medicines and lifestyle modifications including strategies to stop smoking and a walking program to optimize their general health. People who require an operation might have a traditional open surgery or a less invasive procedure known as angioplasty, which uses a balloon to open the blockages in the arteries. A new type of angioplasty, known as drug-eluting balloon (DEB) angioplasty, has emerged as a promising alternative to traditional balloon angioplasty for the treatment of patients with PAD. By using DEBs to balloon and coat the inside of the blood vessels (tubes that carry blood around the body) with medicines to treat cancer (chemotherapy) such as paclitaxel, the hope is to halt the progression of PAD and prevent or postpone its devastating complications. The goal of this review was to determine how DEB angioplasty compares with traditional balloon angioplasty for the treatment of PAD of the lower limbs.

Study characteristics and key results

Our review included 11 clinical trials that randomized 1838 participants (current until December 2015). The trials included thigh and leg arteries above and below the knee. The trials were carried out in Europe and the USA, and all used DEBs that contained paclitaxel. Four companies manufactured the DEB devices: Bard, Bavaria Medizin, Biotronik, and Medtronic. Most participants were followed for 12 or more months (called follow-up). At six and 12 months of follow-up, DEBs were associated with improved primary vessel patency, which is an indicator of whether a vessel is still patent without any further interventions (blood flowing well), late lumen loss, which is the difference in millimeters between the angioplastied segment and how narrow it is on follow-up, target lesion revascularization, which is an indicator of whether a person received more than one treatment to the same artery during the period covered by the study, and binary restenosis, which occurs when a treated artery becomes narrowed again after being previously treated.

Unfortunately, early anatomic (structural) advantages of DEBs were not accompanied by improvements in quality of life, functional walking ability, or in the occurrence of amputation or death. When we specifically examined arteries below the knee and people who had very advanced PAD, we found no clinical or angiographic advantage for DEBs at 12 months of follow-up compared with uncoated balloon angioplasty. In summary, DEBs have several anatomic advantages over uncoated balloons for the treatment of lower limb PAD for up to 12 months after undergoing the procedure. However, more data are needed to assess the long-term results of this treatment option adequately.

Quality of the evidence

All the trials had differences in the way in which they inserted the balloons, and in the type and duration of additional antiplatelet (anticlotting) therapy, leading to downgrading of the quality of the evidence. The quality of the evidence presented was moderate for target lesion revascularization and change in Rutherford category (a way of classifying PAD), and high for amputation, primary vessel patency, binary restenosis, death, and change in ankle-brachial index (which is used to predict the severity of PAD).

Authors' conclusions: 

Based on a meta-analysis of 11 trials with 1838 participants, there is evidence of an advantage for DEBs compared with uncoated balloon angioplasty in several anatomic endpoints such as primary vessel patency (high-quality evidence), binary restenosis rate (moderate-quality evidence), and target lesion revascularization (low-quality evidence) for up to 12 months. Conversely, there is no evidence of an advantage for DEBs in clinical endpoints such as amputation, death, or change in ABI, or change in Rutherford category during 12 months' follow-up. Well-designed randomized trials with long-term follow-up are needed to compare DEBs with uncoated balloon angioplasties adequately for both anatomic and clinical study endpoints before the widespread use of this expensive technology can be justified.

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Background: 

Atherosclerotic peripheral arterial disease (PAD) can lead to disabling ischemia and limb loss. Treatment modalities have included risk factor optimization through life-style modifications and medications, or operative approaches using both open and minimally invasive techniques, such as balloon angioplasty. Drug-eluting balloon (DEB) angioplasty has emerged as a promising alternative to uncoated balloon angioplasty for the treatment of this difficult disease process. By ballooning and coating the inside of atherosclerotic vessels with cytotoxic agents, such as paclitaxel, cellular mechanisms responsible for atherosclerosis and neointimal hyperplasia are inhibited and its devastating complications are prevented or postponed. DEBs are considerably more expensive than uncoated balloons, and their efficacy in improving patient outcomes is unclear.

Objectives: 

To assess the efficacy of drug-eluting balloons (DEBs) compared with uncoated, nonstenting balloon angioplasty in people with symptomatic lower-limb peripheral arterial disease (PAD).

Search strategy: 

The Cochrane Vascular Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched December 2015) and Cochrane Register of Studies (CRS) (2015, Issue 11). The TSC searched trial databases for details of ongoing and unpublished studies.

Selection criteria: 

We included all randomized controlled trials that compared DEBs with uncoated, nonstenting balloon angioplasty for intermittent claudication (IC) or critical limb ischemia (CLI).

Data collection and analysis: 

Two review authors (AK, TA) independently selected the appropriate trials and performed data extraction, assessment of trial quality, and data analysis. The senior review author (DKR) adjudicated any disagreements.

Main results: 

Eleven trials that randomized 1838 participants met the study inclusion criteria. Seven of the trials included femoropopliteal arterial lesions, three included tibial arterial lesions, and one included both. The trials were carried out in Europe and in the USA and all used the taxane drug paclitaxel in the DEB arm. Nine of the 11 trials were industry-sponsored. Four companies manufactured the DEB devices (Bard, Bavaria Medizin, Biotronik, and Medtronic). The trials examined both anatomic and clinical endpoints. There was heterogeneity in the frequency of stent deployment and the type and duration of antiplatelet therapy between trials. Using GRADE assessment criteria, the quality of the evidence presented was moderate for the outcomes of target lesion revascularization and change in Rutherford category, and high for amputation, primary vessel patency, binary restenosis, death, and change in ankle-brachial index (ABI). Most participants were followed up for 12 months, but one trial reported outcomes at five years.

There were better outcomes for DEBs for up to two years in primary vessel patency (odds ratio (OR) 1.47, 95% confidence interval (CI) 0.22 to 9.57 at six months; OR 1.92, 95% CI 1.45 to 2.56 at 12 months; OR 3.51, 95% CI 2.26 to 5.46 at two years) and at six months and two years for late lumen loss (mean difference (MD) -0.64 mm, 95% CI -1.00 to -0.28 at six months; MD -0.80 mm, 95% CI -1.44 to -0.16 at two years). DEB were also superior to uncoated balloon angioplasty for up to five years in target lesion revascularization (OR 0.28, 95% CI 0.17 to 0.47 at six months; OR 0.40, 95% CI 0.31 to 0.51 at 12 months; OR 0.28, 95% CI 0.18 to 0.44 at two years; OR 0.21, 95% CI 0.09 to 0.51 at five years) and binary restenosis rate (OR 0.44, 95% CI 0.29 to 0.67 at six months; OR 0.38, 95% CI 0.15 to 0.98 at 12 months; OR 0.26, 95% CI 0.10 to 0.66 at two years; OR 0.12, 95% CI 0.05 to 0.30 at five years). There was no significant difference between DEB and uncoated angioplasty in amputation, death, change in ABI, change in Rutherford category and quality of life (QoL) scores, or functional walking ability, although none of the trials were powered to detect a significant difference in these clinical endpoints. We carried out two subgroup analyses to examine outcomes in femoropopliteal and tibial interventions as well as in people with CLI (4 or greater Rutherford class), and showed no advantage for DEBs in tibial vessels at six and 12 months compared with uncoated balloon angioplasty. There was also no advantage for DEBs in CLI compared with uncoated balloon angioplasty at 12 months.

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