Author + information
- Received February 14, 2011
- Revision received May 17, 2011
- Accepted May 24, 2011
- Published online September 6, 2011.
- Andrej Schmidt, MD⁎,⁎ (, )
- Michael Piorkowski, MD⁎,
- Martin Werner, MD⁎,
- Matthias Ulrich, MD⁎,
- Yvonne Bausback, MD⁎,
- Sven Bräunlich, MD⁎,
- Henrik Ick, MD⁎,
- Johannes Schuster, MD⁎,
- Spiridon Botsios, MD⁎,
- Hans-Joachim Kruse, MD†,
- Ramon L. Varcoe, MD‡ and
- Dierk Scheinert, MD⁎
- ↵⁎Reprints requests and correspondence:
Dr. Andrej Schmidt, Center of Vascular Medicine, Angiology and Vascular Surgery, Parkkrankenhaus Leipzig, Strümpellstrasse 41, 04289 Leipzig, Germany
Objectives The purpose of this study was to investigate the efficacy of drug-eluting balloons (DEBs) in the treatment of long infrapopliteal lesions with regard to the short-term restenosis rate and midterm clinical result.
Background Restenosis rates of long-segment tibial artery disease are very high. Recently, a restenosis rate of 69% at 3 months after standard balloon angioplasty was demonstrated.
Methods Infrapopliteal angioplasty was performed with a paclitaxel-eluting balloon (In.Pact Amphirion, Medtronic, Minneapolis, Minnesota). Clinical and angiographic follow-up was performed at 3 months to detect binary restenosis, and further clinical assessment was performed over a 12-month period thereafter.
Results In 104 patients, 109 limbs were treated for critical limb ischemia (82.6%) or severe claudication (17.4%). Mean lesion length of the arteries treated was 176 ± 88 mm. Angiography studied in 84 treated arteries at 3 months showed a restenosis in 27.4% (19.1% had restenosis of more than 50%, and 8.3% were totally occluded) and usually occurred focally. Only in 9.5% of all angiographically followed up arteries was the entire treated segment restenosed or reoccluded. During a follow-up period of 378 ± 65 days, 1 patient was lost and 17 died. Of the 91 limbs remaining in the analysis, clinical improvement was present in 83 (91.2%). Complete wound healing occurred in 74.2%, whereas major amputation occurred in 4 patients, resulting in limb salvage of 95.6% for patients with critical limb ischemia.
Conclusions The early restenosis rate of long-segment infrapopliteal disease is significantly lower after treatment with DEBs compared with historical data using uncoated balloons. Randomized trials are required to show whether this difference will lead to improvement in clinical outcomes.
Percutaneous transluminal angioplasty (PTA) is increasingly used to treat infrapopliteal arterial disease. However, the high restenosis rate is problematic, and repeat interventions may be required in a significant proportion of patients to achieve clinical goals (1,2). Drug-eluting stents have been demonstrated to be effective in lowering the restenosis rate below the knee (BTK) (3). Their design for coronary arteries makes them a practical option more suited to shorter tibial lesions. For long-segment BTK disease, drug-eluting balloons (DEBs) have been designed to reduce the restenosis rate. Initially emerging as a new treatment option for coronary arteries (4), they also have been studied in the femoropopliteal segment (5,6). In our registry, we aimed to investigate a recently approved DEB for its application in infrapopliteal arteries.
Patient selection and interventional technique
Consecutive patients with critical limb ischemia (CLI) or severe claudication and BTK lesions (stenosis: ≥70% or occlusions) with a lesion length of 80 mm or more were treated with a paclitaxel-eluting balloon (In.Pact Amphirion, Medtronic, Minneapolis, Minnesota). The balloon is coated with FreePac, a proprietary formulation of 3.0 μg paclitaxel/mm2 and urea, which serves as a hydrophilic spacer to facilitate separation and release of paclitaxel into the vessel wall. Pre-dilation with an uncoated balloon was performed to ensure an uncomplicated insertion of the DEB into the lesions. The DEB diameter was 0.5 mm larger than the uncoated balloon to guarantee contact of the DEB to the arterial wall. DEBs had a diameter of 2.0 to 4.0 mm and a length of 80 to 120 mm. If more than 1 balloon was used per lesion, overlap of the DEBs was 5 mm. Inflation time was at least 1 min. In case of flow-limiting dissection or residual stenosis of more than 30%, a prolonged dilation of up to 5 min was performed. Stents were used as bailout for unsatisfactory results. Success was defined as at least 1 infrapopliteal artery restoration in continuity to the foot with a residual stenosis of less than 30%. Inflow lesions were treated during the same session.
All patients were taking aspirin 100 mg daily. After sheath insertion, 5,000 IU heparin was administered. After angioplasty, intra-arterial nitroglycerin 200 to 300 μg was administered routinely to resolve vasospasm. Post-intervention dual antiplatelet therapy with aspirin 100 mg and clopidogrel 75 mg once daily was given at least for 4 weeks and 100 mg aspirin was given daily thereafter.
The primary endpoint was the angiographic binary restenosis. Angiographic follow-up was scheduled 3 months after the initial procedure according to our hospital standards. Selective angiographies in 2 different projections were evaluated by 2 investigators based on visual estimate. Binary restenosis was calculated using a 50% diameter reduction threshold. Clinical outcome was assessed at 3 and 12 months after angioplasty. Clinical improvement was defined as marked (≥50%) reduction of ulcer size or depth or increase of at least 1 Rutherford-Becker category. Amputations and the necessity for target lesion revascularization (TLR) or bypass surgery were recorded. This study was performed without industry financial support. Data analysis was performed retrospectively. The registry adhered to the requirements of the local ethics committee, and all patients gave their written informed consent before the procedure.
Continuous data are given as mean ± SD. Categorical variables are expressed as numbers and percentage.
Baseline characteristics of patients and lesions
Between January 2009 and February 2010, 104 consecutive patients meeting the inclusion criteria were studied. In these patients, 109 limbs were treated either for CLI (82.6%) or severe claudication (17.4%). Patient characteristics are given in Table 1.
Before treatment, 77.1% of the patients had complete or functional occlusion of all 3 infrapopliteal arteries. Mean infrapopliteal lesion length was 176 ± 88 mm. The number of arteries treated was left to the discretion of the interventionalist; however, in only 5 limbs was more than 1 artery treated.
The mean number of DEBs used per artery was 1.9 (range: 1 to 5). In 28 limbs, a proximal angioplasty (all infrainguinal) was performed additionally during the same intervention using uncoated balloons.
Interventional success was achieved in all limbs, and stenting was necessary in 5 cases. Inevitable toe amputation was performed in 3 patients in the peri-interventional period. Complications before discharge included 3 femoral pseudoaneurysms, only 1 requiring surgical repair. One patient with an infected diabetic foot who was Rutherford-Becker category 6 died as a result of a major amputation performed 21 days after PTA.
During this period, 8 additional patients died, 7 of cardiac disease and 1 of a bronchial cancer diagnosed before PTA. One patient was lost for follow-up. Clinical improvement in the remaining 94 patients was seen in 75.8% of the treated limbs, 22.2% were unchanged, and 2.0% were clinically worse. Three additional toe amputations were performed. Complete wound healing was noted in 41.9% of the Rutherford-Becker category 5 limbs. Twenty patients declined to undergo repeat angiography. There was no difference in lesion characteristics or 3-month clinical outcomes between the patients with or without repeat angiography.
Subgroup of angiographically examined patients at 3 months
Angiography at 3 months was performed in 74 patients with 79 treated limbs and 84 arteries treated with DEBs. Lesion characteristics are given in Table 2. Before PTA, target arteries were stenosed in 38.1% and were occluded in 61.9%. Angioplasty was performed for 55 de novo lesions, 19 restenoses, and 10 in-stent restenoses. Mean lesion length was 173 ± 87 mm and mean DEB diameter was 2.72 ± 0.41 mm. Bailout stenting was performed in 5 cases. Cypher stents (Cordis, Miami, Florida) were used in 3 cases, and self-expanding nitinol stents (Maris Deep, Medtronic) were used in 2 cases. Full lesion coverage was performed in 1 of the cases.
Angiography at 3 months (mean 98 ± 22 days) found 61 (72.6%) of 84 arteries free of significant restenosis. In 27.4%, a restenosis of more than 50% was found (19.1% had a restenosis and 8.3% were occluded). In most of these cases (61%), restenosis developed only focally (<20% of the length of the initial target lesion) (Fig. 1). Restenosis or reocclusion of the entire target lesion occurred only in 8 (9.5%) of the 84 treated arteries. Higher restenosis rates were seen after treatment of distal segments, especially when foot arteries were involved (Table 2). Two (2.4%) of the 84 treated arteries became ectatic within the treated segment (less than double of the reference vessel diameter), and 1 was associated with restenosis. Clinical improvement in limbs with restenosis was similar to that of those without.
Midterm clinical follow-up
After a mean follow-up of 378 ± 65 days, 86 patients with 91 treated limbs were evaluated clinically. Clinical improvement occurred in 91.2% of these limbs. No bypass surgery was performed during the entire study period. TLR was performed in 17.3%. Limb salvage was achieved in 95.6% of the CLI patients and complete wound healing occurred in 74.2% of the patients with Rutherford-Becker category 5 at baseline. Eight additional patients died, all for unrelated reasons, resulting in a mortality rate of 16.3% at 1 year. There were 4 unplanned amputations during this period, 1 single toe amputation, 1 forefoot amputation, and 2 major BTK amputations. The Rutherford-Becker categories of all patients before and after 1 year are shown in Figure 2.
The restenosis rate after PTA of infrapopliteal arteries is very high. In a series recently published treating infrapopliteal arteries with a mean lesion length of 183 mm with uncoated low-profile balloons, we demonstrated an angiographic restenosis rate of 69% at 3 months (2). Because of this finding, we selected long BTK lesions for treatment with the recently approved infrapopliteal DEB (In.Pact Amphirion). The mean lesion length of 173 mm in this series is comparable in length with that of our previous study (2). The 3-month restenosis rate of 27% after treatment with DEB represents a dramatic reduction for restenosis of 61% from the 69% seen in the series using uncoated balloons (2). In addition, we observed an altered pattern of recurrent disease that favored the DEB. Whereas restenosis usually involved the whole treated segment with uncoated balloons (2), restenosis after DEB was found to be focal, involving <20% of the length of the target lesion in more than 60% of the restenosed vessels. This pattern of shorter restenosis may have less impact on flow compared with the diffuse type and also simplifies TLR.
Although our series is too small to perform a meaningful subanalysis of factors that may influence patency after PTA with DEBs, the most distal lesions seem to perform worst. For DEB angioplasty distal to the malleolus, we found a restenosis rate of 38.5% at 3 months. This is consistent with other published series that recognize standard balloon angioplasty for pedal arteries to be a predictor of limb loss (1). The high restenosis rate we observed in this region may be a contributing factor.
Safety of DEBs in BTK arteries
We found nothing to indicate the use of DEBs BTK to be unsafe. An amputation rate of 4.4% is very acceptable for CLI patients. During the 3-month angiogram, 2 arteries became moderately ectatic within the treated segment, which resulted in no adverse clinical events. This has not been described previously for DEBs for other arteries. We do not believe that this observation raises concerns regarding the safety of DEBs in the infrapopliteal circulation.
Multiple factors contribute to wound healing and limb salvage, including local wound care and surveillance regimen, which may be equally as important as revascularization. It therefore may be difficult to prove the superiority of the DEBs over uncoated balloons for these clinical endpoints. In fact, similar favorable results for wound healing and limb salvage have been described after plain old balloon angioplasty of long infrapopliteal disease (2,7). TLRs frequently are needed after endovascular treatment of BTK arteries (1,2) and therefore may be considered a more useful clinical endpoint. Compared with the TLR rate of 50% in our series using uncoated balloons (2), the use of DEBs resulted in a TLR rate of 17.3%, a considerable reduction of 65.4%. It is with regard to TLR that the use of DEBs has most potential to improve clinical outcomes compared with standard balloons. Costs are likely to play an important role for the use of DEB; however, the potential reduction in number of reinterventions also must be considered in these calculations if we are to compare DEBs with uncoated balloons.
Quantitative angiography to determine degree of restenosis in long BTK lesions is technically very challenging. In practice, however, the visual assessment of angiography was believed to be significantly more precise than the alternatives of duplex ultrasound, magnetic resonance angiography, or computed tomography angiography. Only 1 DEB, the In.Pact Amphirion, was approved for peripheral artery application in Europe and therefore was the only one used during the study period. Other DEBs may lead to differing results in the future.
This first report of the use of DEBs BTK suggests that they are safe and effective in this arterial region. When compared with a series using uncoated balloons, the data presented here demonstrate a marked, more than 60% reduction in the restenosis rate at 3 months. In addition, if restenosis occurred, it was associated with a favorable, focal pattern. The 1-year clinical results are promising and seem to confer a durable benefit. Further evidence, in the form of randomized controlled trials, is required to confirm whether DEBs are superior to the standard treatment of plain old balloon angioplasty in patients with CLI from BTK disease.
Drs. Schmidt and Scheinert are consultants for Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- below the knee
- critical limb ischemia
- drug-eluting balloon
- percutaneous transluminal angioplasty
- target lesion revascularization
- Received February 14, 2011.
- Revision received May 17, 2011.
- Accepted May 24, 2011.
- American College of Cardiology Foundation