Treatment of subacute and chronic thrombotic occlusions of lower extremity peripheral arteries with the excimer laser: a feasibility study

Abstract

Thrombus is highly prevalent in patients with recent symptoms (< 6 months) of claudication or limb ischemia due to an occluded culprit lower extremity vessels. Treatment of these thrombotic occlusions is challenging. In this feasibility study, the excimer laser (Spectranetics, Colorado Springs, CO) has been tested for its safety and ability to ablate thrombus in patients with recent arterial occlusions. Angiographic operator assessment and volumetric core lab quantitation of the thrombus were performed at baseline and after excimer laser but prior to definitive treatment of the vessel to evaluate thrombus resolution. Consecutive patients were prospectively enrolled at a single site. Procedural success was defined as achieving a residual stenosis of <30% after final treatment with no intraprocedural complications requiring additional treatment. 20 consecutive patients were enrolled in this study (8 males, mean age 69.5±11.1 years). Based on patients symptom onset, 12 patients were subacute (> 24 h, < 30 days), and 8 chronic (between 1 to 6 months). 15/20 (75%) had restenotic occlusions. Due to the long, occlusive nature of these lesions, only 8 patients had complete intravascular ultrasound images at each time point which allowed volumetric analysis by the core lab. There was no statistical difference in plaque/thrombus volume between baseline (pretreatment) and excimer laser (P=.68). There was however a significant reduction in residual angiographic stenosis post laser alone (100% vs. 66.75%±23.9%, P=.001). Procedural success was 100%. There were no deaths or amputations. Bail out stenting was performed in 10/20 (50%) patients. Embolic filters were used in 15/20 (75%) of patients. Macrodebris>2 mm were seen in 85.7% of filters. There was no in-hospital or 30-day reocclusion of the treated vessel but one patient had a vascular access complication (small AV fistula) conservatively managed. No other serious adverse events were noted. Using the excimer laser appears safe in this small feasibility study of subacute and chronic thrombotic occlusions. Angiographically, there was a significant reduction in percent stenosis with the laser alone. The limited IVUS data did not show a reduction in plaque/thrombus volume but the number of interpretable ultrasounds was small. Further data are needed to address the effectiveness of the laser in treating these thrombotic occlusions and its advantages over balloon angioplasty.