High Dose-rate Brachytherapy For Lower Extremity In-stent Restenosis: A 18-year, Single-center Experience

Abstract

INTRODUCTION AND OBJECTIVES We present our 18-year experience of endovascular brachytherapy (EVBT), which was previously validated as a treatment for in-stent restenosis (ISR). METHODS We performed a single-center retrospective analysis of outcomes in 158 patients who underwent PTA and EVBT from 2003 to 2020. A dose of 20Gy was given at a depth of 0.5mm beyond the radius of the largest PTA balloon using iridium-192, with at least 2-cm-long margins of radiation coverage proximal and distal to the injured area. Stents were assessed for patency by duplex ultrasound imaging or angiography at 1, 3, 6, 9, 12, and 18 months and then yearly. The primary endpoint was freedom from 50% restenosis in the treated segment at 1 year, and 2 years. Patency data were estimated using the Kaplan-Meier method. Secondary endpoints were early and late thrombotic occlusion. RESULTS Of the 174 consecutive cases of EVBT, 29 (16.7%) were performed in common, external, or internal iliac, 145 (83.3%) in common femoral, superficial femoral, or popliteal arteries, or both. 142 patients (89.9%) had claudication, and 16 (10.1%) had critical limb ischemic symptoms. Preliminary analysis revealed the mean treated length to be 24.1 ± 12.3 cm over a mean duration of 16.5 ± 9.6 minutes. Median post-EVBT follow-up time was 2670 days (range, 1-4154 days). There were six (3.4%) and eighteen (10.3%) cases of early and late thrombotic occlusions, respectively. There were two deaths secondary acute coronary syndrome and stroke. Primary, assisted primary, and secondary patency in the entire cohort was 77.5%, 88.6%, and 90.6%, respectively, at 1 year and 64.8%, 79,2%, and 83.6%, respectively, at 2 years. CONCLUSIONS Our validated PTA with adjunctive EVBT protocol, followed by a consistent surveillance strategy, proves to offer a viable treatment option of ISR in centers that have the capacity to collaborate with Radiation Oncology. We present our 18-year experience of endovascular brachytherapy (EVBT), which was previously validated as a treatment for in-stent restenosis (ISR). We performed a single-center retrospective analysis of outcomes in 158 patients who underwent PTA and EVBT from 2003 to 2020. A dose of 20Gy was given at a depth of 0.5mm beyond the radius of the largest PTA balloon using iridium-192, with at least 2-cm-long margins of radiation coverage proximal and distal to the injured area. Stents were assessed for patency by duplex ultrasound imaging or angiography at 1, 3, 6, 9, 12, and 18 months and then yearly. The primary endpoint was freedom from 50% restenosis in the treated segment at 1 year, and 2 years. Patency data were estimated using the Kaplan-Meier method. Secondary endpoints were early and late thrombotic occlusion. Of the 174 consecutive cases of EVBT, 29 (16.7%) were performed in common, external, or internal iliac, 145 (83.3%) in common femoral, superficial femoral, or popliteal arteries, or both. 142 patients (89.9%) had claudication, and 16 (10.1%) had critical limb ischemic symptoms. Preliminary analysis revealed the mean treated length to be 24.1 ± 12.3 cm over a mean duration of 16.5 ± 9.6 minutes. Median post-EVBT follow-up time was 2670 days (range, 1-4154 days). There were six (3.4%) and eighteen (10.3%) cases of early and late thrombotic occlusions, respectively. There were two deaths secondary acute coronary syndrome and stroke. Primary, assisted primary, and secondary patency in the entire cohort was 77.5%, 88.6%, and 90.6%, respectively, at 1 year and 64.8%, 79,2%, and 83.6%, respectively, at 2 years. Our validated PTA with adjunctive EVBT protocol, followed by a consistent surveillance strategy, proves to offer a viable treatment option of ISR in centers that have the capacity to collaborate with Radiation Oncology.