Background: Intracoronary radiation therapy (IRT) is well established in clinical practice as an effective treatment for in-stent restenosis (ISR). We aimed to determine if the 6-month clinical outcome of patients (pts) treated post-approval for marketing [commercial radiation, (CR)] is equivalent to those pts enrolled in the Washington Radiation for In-Stent restenosis Trials [Gamma WRIST & Beta WRIST, Investigational Radiation, (IR)].
Methods: The 6-month clinical outcome of 110 consecutive pts with 125 lesions who received IRT [gamma, 192Ir, 15-18 Gy (n=6)], or [beta, 32P, 20 Gy (n=20) or 90Sr/Y, 18.4-23.0 Gy, (n=99)] in CR was compared with the 6-month clinical outcome of 117 pts with 117 lesions who received IRT [192Ir, 15 Gy (n=65) in ���Gamma WRIST���] and [90Y, 20.6 Gy (n=52) in ���Beta WRIST���] in IR. Pts in the CR were treated with wider radiation margins. The CR received antiplatelet therapy for at least 6 months and the IR for 1 month.
Results: The baseline characteristics of both groups were similar. Use of atheroablation devices was less in CR (15.2% vs 32.8% in IR, P=0.001). The overall major adverse cardiac events (MACE; Death, Q-wave MI and TVR, 18.2% vs 29.1% in IR, P=0.05) were significantly lower in the CR when compared with pts in the IR.
Conclusion: The ���real world��� clinical practice of IRT demonstrates lower events and better clinical outcomes. This is most likely a result of implementation of the lessons learned from the clinical trials such as optimizing the dosimetry by using a higher dose, treating wider margins to minimize edge effect, and administering prolonged antiplatelet therapy to abolish late thrombosis.