Safety and Efficacy of Intracoronary Brachytherapy Protocol for Resistant In-Stent Restenosis

Abstract

The aim of our prospective study is to evaluate the safety and the long-term clinical efficacy of Intracoronary Brachytherapy (ICBT) for In-stent Restenosis utilizing a prespecified interventional and radiation protocol.Single center prospective analysis of patients undergoing ICBT with at least 2 prior layers of coronary stents compared to patients undergoing balloon angioplasty alone. Per our protocol, the first step is to perform an intravascular ultrasound (IVUS) study to evaluate the lesion for degree of calcification, etiology of ISR, length of the lesion and diameter of the vessel. Then, laser atherectomy is performed using 0.9, 1.4- or 1.7-mm catheters for 3 runs. Percutaneous transluminal coronary angioplasty (PTCA) of the culprit lesion with a 1:1 sized cutting balloon is performed. Then, ICBT is performed and IVUS is repeated to confirm appropriate MLA. Target Vessel Revascularization rates within one year of ICBT will be assessed. Periprocedural complications will be assessed for up to 72 hours. Side branch occlusion: > 50% stenosis of the side-branch of the target vessel during/immediately after completion of ICBT. Absence of TIMI III flow distally in the target vessel after ICBT will also be assessed.Results for our project are forthcoming however we have completed 32 brachytherapy treatments in our laboratory since 2016 and their results are presented herein. Significant side branch occlusion occurred in only 4 cases (13%). Distal slow flow or no flow occurred in 3 cases (9%). TIMI 3 flow was restored in all 3 cases. TVR occurred in only 3 cases (9%). Bleeding complications occurred in 3 cases, 2 patients had a hematoma and one had bleeding at the access site. Only one case required one unit of blood transfusion. Acute renal failure occurred in one case. There were no 30-day readmissions to our hospital for any of the patients who received ICBT. 30-day survival was observed in all 32 patients. The 8 patients who qualified for ICBT during the same time period of January 2016 to December 2020 but had PTCA alone or atherectomy and PTCA had TVR observed in 5/8 cases (63%); This was significantly higher than in those patients who underwent ICBT (P < .001). Side branch occlusion did not occur in any of the 8 cases. None of the cases had a distal slow flow or no flow phenomenon. None of the patients had acute renal failure. There were no 30-day readmissions and all of the patients survived to 30 days.In-stent restenosis of DES is an important clinical issue. Intracoronary brachytherapy is a safe and well tolerated treatment option that may serve as a form of therapy for high-risk patients with recurrent ISR of DES. At our high-volume institution we have created a systematic protocol for ICBT. We look forward to updating the clinical results from our prospective study.