Abstract
Background: Most studies that proved intracoronary radiation therapy (IRT) to be highly effective to reduce recurrent restenosis after treatment of in‐stent restenosis (ISR) have looked at time periods up to 12 months. Whether the beneficial effect from radiation is sustained during long‐term follow‐up remains a concern. This study sought to evaluate the effectiveness of IRT using a β‐emitter during a 3‐year follow‐up period. Methods: One hundred twenty‐eight consecutive symptomatic patients (mean age, 63 ± 11 years) with 134 in‐stent restenotic lesions were treated for ISR with IRT (noncentred β‐emitter, Novoste; radiation dosis 21.1 ± 3.1 Gy). Six‐month angiographic follow‐up was obtained in 104 patients (81%) with 105 lesions (78%). All patients underwent 36‐month clinical follow‐up. Results: Six‐month angiographic restenosis rate was 22% in stent (29% in lesion) with an in‐stent late loss of 0.49 ± 0.62 mm. Target lesion resvascularization (TLR) at 6‐month follow‐up was performed in 23 cases (18%). MACE (death, myocardial infarction, and target vessel revascularisation) was observed in 24 patients (19%). At 36‐month follow‐up, TLR increased to 36 cases (28%) and MACE was observed in 47 patients (37%). In a multivariate analysis, minimal lumen diameter before treatment of ISR using IRT was the only predictor of recurrent TLR at 36 months (OR = 0.131; 95% CI, 0.068–0.254; p = 0.002). In a subgroup of patients (N = 15) without restenosis at 6‐month angiography but with clinically driven recurrent late angiography (mean, 18 ± 7 months); in‐lesion late loss increased from 0.47 ± 0.54 mm at 6 months to 1.27 ± 0.76 mm at repeated angiography (p = 0.005). Conclusion: There is a considerable number of delayed recurrent restenosis post IRT for ISR. This is due to ongoing late loss more than 6‐month post IRT. The minimal lumen diameter before IRT predicts the need for recurrent TLR at 36 months. © 2006 Wiley‐Liss, Inc.