Commentary: What Is the Optimal Endovascular Treatment for Infrapopliteal Bifurcation Disease?

Approximately 8.5 million American adults are affected by peripheral artery disease. ¹ Endovascular interventions, including angioplasty, are indicated when there is disabling claudication or critical limb ischemia (CLI) with ischemic rest pain or tissue loss. ² Increasingly, complex infrapopliteal disease is treated with advanced endovascular techniques. One difficult clinical situation involves treatment of bifurcation disease, such as at the origin of the peroneal and posterior tibial arteries. When both branches of these arteries are severely diseased, single balloon angioplasty can shift plaque into the untreated adjacent branch and cause dissection, vessel closure, or thrombus formation. While there is a wealth of data on strategies to treat bifurcation lesions in the coronary circulation, there is little published on advanced angioplasty techniques to treat below-knee (BK) bifurcation lesions. ³ One strategy when there is true bifurcation disease involving a distal main branch and a side branch is to place guidewires in both branches and simultaneously inflate balloons in a manner that traps plaque and prevents displacement to a contralateral unprotected branch. ⁴ In cases of continued dissection or vessel closure, provisional stent placement can be considered, using techniques adopted from the treatment of coronary bifurcation disease. ⁵

The report by Iezzi et al ⁶ in this issue of the JEVT describes the use of cutting balloon angioplasty (CBA) in the treatment of BK bifurcation disease. In this retrospective single-center study, the authors treated 47 infrapopliteal bifurcation lesions in 25 limbs using CBA. In all cases, both the main and side branches had guidewires positioned in them. Eleven of the limbs had true bifurcation lesions, whereas 14 limbs had bifurcation lesions primarily involving one side branch. T-shaped double CBA or double kissing CBA was used in true bifurcation lesions, whereas single CBA was employed in lesions with involvement of primarily one side branch. All lesions were successfully treated without flow-limiting dissection, and there was no need for stent implantation. During follow-up, the clinical status improved in all patients, with associated improvement in Rutherford class and ankle-brachial index. Primary patency (<50% diameter stenosis determined by either duplex or computed tomography) was 89% at 6 months and 78% at 12 months. Ten lesions developed recurrent stenosis, and 5 (11%) lesions underwent reintervention; 1 patient required a major amputation (96% limb salvage rate). Two patients underwent preplanned minor amputations.

This study is one of the first reports of CBA for the treatment of infrapopliteal bifurcation disease. The results confirm the concept that CBA can be employed successfully to minimize plaque shift and optimize angiographic results in bifurcation disease. However, it is not clear from this study how patients with CLI and infrapopliteal bifurcation disease were selected for CBA during the study period from November 2010 to March 2013. The selection of patients for CBA is a likely source of bias that has to be considered when comparing the effectiveness and safety of CBA with other treatment strategies in infrapopliteal bifurcation lesions. Additional limitations of the report include the small number of patients enrolled and the retrospective, observational, single-arm design. There is no control group, making it difficult to analyze the comparative effectiveness of CBA against other treatment strategies, including conventional balloon dilation or stenting.

The treatment of BK bifurcation disease is an evolving area of endovascular therapy in CLI. By extension from coronary artery techniques, some investigators have reported results of coronary drug-eluting stents (DES). Werner et al ⁵ treated 11 patients with CLI and BK bifurcation disease with Cypher or Xience V coronary DES as a bailout option after unsuccessful balloon angioplasty. Two-vessel primary patency was 55%, whereas 1-vessel primary patency was 82% following 6 months of surveillance. The relatively high restenosis/reocclusion rates after bailout stenting compared with the report by Iezzi et al ⁶ likely reflects 2 issues. First, the complexity of the underlying lesions may be higher in cases that require bailout stenting. Second, the divergent results may stem from the inherent different outcomes after using conventional angioplasty as opposed to CBA. In a larger series of 39 CLI patients in whom 41 BK bifurcation lesions were treated with direct or primary DES, the 2-vessel primary patency rate at 1 year was 78%. ⁷ These results were comparable to the patency rate achieved with CBA in the report by Iezzi et al. ⁶ These findings suggest that CBA may be preferable to primary DES in BK bifurcation lesions despite similar primary patency rates, as stent implantation impacts subsequent surgical bypass options, requires longer-term dual antiplatelet therapy, and predisposes to stent fracture.

Other approaches to treatment of infrapopliteal bifurcation disease may include novel devices, such as a dedicated bifurcation stent, scoring balloon angioplasty, or drug-coated balloon angioplasty. The Nile Croco dedicated bifurcated stent (Minvasys, Gennevilliers, France), a balloon-expandable bare metal stent with a short scaffold at the side port to provide coverage of the side-branch ostium and allow access to the side branch, has been used in CLI patients with infra-popliteal bifurcation disease, with a reported primary patency rate of 96% at 1 year. ⁸ While data on the use of scoring balloon angioplasty in infrapopliteal bifurcation lesions is lacking currently, a study of 31 CLI patients with complex tibioperoneal atherosclerotic disease and single-vessel runoff to the ankle reported that scoring balloon angioplasty was associated with a need for bailout stenting in 11 patients and a 61% primary patency rate. ⁹ Drug-coated balloons will likely be another attractive option in this complex group of CLI patients, but no data are currently available on this application. The lack of benefit in a recent trial of patients with CLI may also limit the use of drug-coated balloons in this population until additional data are available. ¹⁰

The report by Iezzi et al ⁶ is the first description of the use of CBA for BK bifurcation disease in CLI. The findings suggest good immediate technical results without the development of flow-limiting dissection or need for bailout stenting, as well as satisfactory 1-year primary patency rates. The generalizability of these findings may be limited by potential selection bias of patients for CBA in the study. Prior to widespread adoption of CBA as the primary strategy for treatment of BK bifurcation lesions in CLI, additional studies are required where this strategy can be prospectively compared with other angioplasty (including scoring balloon and drug-coated balloon) and primary stenting strategies.