Background: Intracoronary radiation with a rhenium-188 (¹⁸⁸Re)-filled balloon is safe and efficiently reduces restenosis, but the injury caused by ¹⁸⁸Re-filled balloon catheter is one of great concerns. The late outcome and the effect of radiation on dissection resolution have not been known.
Method: After successful catheter-based treatment of de novo or restenotic lesion, 256 patients were randomly assigned to radiation or control group. ¹⁸⁸Re-filled balloon system was designed to deliver 17.6 Gy at a depth of 1.0 mm into the vessel wall from the balloon-artery interface.
Results: Dissections were identified in 15 patients among the 138 patients of radiation group (10.9%). Stents were deployed in 10 patients to cover the flow-limiting dissection. In the dissected vessels (N=15), the binary restenosis rate (53.3% vs 16.0%, p=0.001) and target vessel revascularization (TVR) rate (53.3% vs 15.4%, p=0.001) were significantly higher than in those without dissection (N=123) at 9 month. Geographic miss (GM) was identified in 4 of the 10 stented patients and the binary restenosis rate in GM group was 100% (4/4), which was significantly higher than non-GM group (33.3%, 2/6, p=0.02). Long-term follow up of dissections without TVR (N=7) showed impairment of dissection healing including three cases of aneurysmal changes (mean follow up duration: 640.7 짹 387.3 day).
Conclusion: The finding that dissection after brachytherapy does not heal after long-term follow-up, confirms that intracoronary radiation impairs the healing process after vessel injury. Stent implantation for the flow-limiting dissection after brachytherapy leads to adverse clinical outcome mainly due to geographical miss.