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A new method for performing endovascular brachytherapy has shown promising results in treating in-stent stenosis of femoropopliteal lesions, according to findings published in the August 2012 issue of the Journal Endovascular Therapy.

The researchers, led by Martin Werner, MD, of the Center for Vascular Medicine at Park Hospital Leipzig (Leipzig, Germany), used beta radiation from liquid rhenium-188 (Re-188) delivered with an angioplasty balloon. They noted that previous attempts at using radiation to treat stenosis in peripheral arteries have been limited due to logistical problems, with late catch-up minimizing efficacy.

For the study, a total of 90 consecutive patients with symptomatic in-stent femoropopliteal stenosis/occlusion of self-expanding nitinol stents underwent angioplasty and endovascular brachytherapy between June 2009 and April 2011 at Park Hospital Leipzig. The Re-188 solution was delivered from an inflated angioplasty balloon to the entire stented segment, even if parts were not restenotic.

The researchers achieved primary technical success in all patients; there was 1 early stent thrombosis immediately after irradiation, which was treated successfully. The procedure showed good results in terms of the main outcome measure of primary patency (< 50% in-stent stenosis on duplex ultrasound) at 6 and 12 months following irradiation, as well as mean Rutherford class and clinical improvement, defined as the percentage of patients showing sustained improvement of at least 1 Rutherford category (table 1).

Table 1. Efficacy of Brachytherapy with Liquid Beta-Emitting Re-188

^a P < 0.001 vs. baseline.

The mean ankle-brachial index for patients without recurrence improved from 0.66 at baseline to 0.94 (P < 0.001) at 6 months and to 0.91 at 12 months (P < 0.001). In addition, Kaplan-Meier estimates of amputation-free survival were 98.9% at 6 months and 97.5% at 12 months.

A total of 89 patients were included in the clinical follow-up, which lasted a mean of 13.5 months. One patient died from an MI 1.3 months following brachytherapy. Two patients had late acute stent thrombosis after 2.2 and 4.1 months, respectively. Both patients were treated successfully with rotational thrombectomy and local thrombolysis. Two other patients had severe infrapopliteal atherosclerotic disease at 11 and 15 months post-procedure and required minor amputations.

A Niche Procedure?

According to the authors, current endovascular treatment of the femoral artery is “rather ineffective,” yielding restenosis rates between 50% and 70% at 6 to 12 months; in contrast, the Re-188 irradiation in the current study yielded a restenosis rate of only 20.1% after 1 year.

The new procedure has logistical advantages; previous attempts at brachytherapy in peripheral arteries have involved gamma radiation with iridium-192, which carries the need for extensive radiation safety measures in the cath lab, they note.

“The Leipzig group has to be applauded for studying the formerly promising therapeutic concept of endovascular brachytherapy, which has not been used for many years in clinical practice mainly due to logistical problems,” writes Erich Minar, MD, of the Medical University of Vienna (Vienna, Austria), in an accompanying editorial. He noted that there are only limited data regarding DES and balloons in non-coronary arteries, and that the positive results with brachytherapy suggest trials comparing radiation with DES are warranted.

Ron Waksman, MD, of Washington Hospital Center (Washington, DC), told TCTMD in a telephone interview that the study does provide good support for the efficacy of radiation in peripheral arteries.

Dr. Waksman noted that previous work on irradiation in coronary arteries suggests there can be some late catch-up. But in many of these patients, and especially those with critical limb ischemia, “their recurrence rate is very early, sometimes within 3 months,” he said. Because of such an early recurrence rate, the 12-month outcomes found in this study are probably a reasonable indicator of success. “I’m not saying it’s sufficient. Obviously you’d like to see longer [follow-up],” he said.

The study is also limited by its retrospective design, but it indicates that brachytherapy could play at least a small role in a difficult patient population. “If we are looking to have a whole array of options for treatment, this study shows that radiation could be one of them,” Dr. Waksman said. “But I don’t think that this would be used as more than a niche procedure.”

Study Details

Patients were mostly men (65.6%) with an average age of 68.3 years. The average treated segment length was 24.6 cm, and 54.4% of patients had a treated segment of more than 20 cm in length. Patients were exposed to radiation for an average of 17.1 minutes in total, with a dose of 13 Gy at a depth of 2 mm into the vessel walls.

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Sources:
1. Werner M, Scheinert D, Henn M, et al. Endovascular brachytherapy using liquid beta-emitting rhenium-188 for the treatment of long-segment femoropopliteal in-stent stenosis. J Endovasc Ther. 2012;19:467-475.

2. Minar E. Resuscitation of endovascular brachytherapy owing to improved logistics. J Endovasc Ther. 2012;19:476-479.

 

 

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