Dethrombosis of lower extremity thrombus by local delivery of thrombolysis using ClearWay transcatheter balloon irrigation: a feasibility study.

Background: Thrombus is highly prevalent in patients with recent symptoms (<6 months) of claudication or limb ischemia with occluded culprit lower extremity arterial vessels. Treatment of these thrombotic occlusions is challenging. In this feasibility study, the Vascular ClearWay Irrigating PTFE Balloon Catheter (Atrium, Husdson, NH, USA) has been tested for its safety and ability to dissolve thrombus in patients with recent arterial occlusions.

Methods: Twenty consecutive patients with lower extremity occlusion were prospectively enrolled to test the feasibility of the ClearWay balloon irrigation system. Cohorts of five patients were tested with increasing doses of tPA (five control patients with saline, five patients with 0.25 mg/cm, five patients with 0.4 mg/cm and five patients with 0.6 mg/cm of lesion length). Volumetric intravascular ultrasound core laboratory assessment of the thrombus was performed at baseline and after ClearWay thrombolysis (but prior to definitive treatment of the vessel with other debulking or stenting) to evaluate the effectiveness of ClearWay to remove thrombus.

Results: Twenty consecutive patients were enrolled in this study (11 men; mean age, 68.54 ± 8.15 years), and 14 had volumetric intravascular ultrasound available both before and after Clearway. Based on patients' symptom onset, 1 patient was acute (< 24 h), 4 subacute (> 24 h, < 30 days) and 15 chronic (between 1 and 6 months). There were no safety events as predefined by the protocol including no major bleeding, death, distal embolization distal to the filter, acute renal failure or vascular complications. Acute procedural success was seen in 100% of cases. There were no statistical difference in plaque-thrombus volume between baseline (pretreatment) and control ClearWay treatment (saline infusion; P = .911, n = 4). Also, there was no statistical difference in plaque-thrombus volume between pretreatment baseline and ClearWay tPA treatment (P = .628, n = 14). Following Angiojet rheolytic thrombectomy (n = 8 patients) post-ClearWay lytic treatment, there was a statistical reduction of plaque-thrombus volume versus ClearWay lytic treatment alone (P = .030) or pretreatment baseline (P = .029). There were no deaths or amputations. Macrodebris > 2 mm were present in 50% of patients captured by embolic filter protection. In-hospital reocclusion of the treated vessel occurred in one patient (5%) and 30-day reocclusion occurred in two patients (10%) on follow-up.

Conclusion: Using the ClearWay to deliver lytic therapy appears safe in this small feasibility study. Although lytic treatment with the ClearWay balloon alone did not demonstrate reduction in plaque-thrombus volume in this small population, the use of Angiojet rheolytic thrombectomy following ClearWay did reduce plaque volume. Further data are needed to address definitive effects of ClearWay balloon alone and utility to facilitate Angiojet thromboreduction.