Sirolimus-eluting stent implantation and β-irradiation for the treatment of in-stent restenotic lesions: Comparison of underlying mechanisms of acute gain and late loss as assessed by volumetric intravascular ultrasound

The aim of the study was to compare the angioplasty mechanisms of drug (sirolimus)-eluting stent (DES) implantation and vascular brachytherapy (VBT) for the treatment of in-stent restenosis (ISR) as assessed by intravascular ultrasound (IVUS). We performed IVUS in 53 patients (28 DES, 25 VBT) before and after angioplasty of ISR and at 6-month follow-up. Cross-sectional areas of the external elastic membrane, the stent, and the lumen were measured. Plaque + media, peristent plaque, and intimal hyperplasia areas were calculated, respectively. Clinical and IVUS baseline characteristics did not differ between groups at baseline. After the index procedure, the lumen at the stent site was smaller in the DES group (DES 6.7 ± 2.0 mm 2 vs VBT 7.5 ± 2.2 mm 2, P = .042). Because of less intimal hyperplasia (DES 0.2 ± 0.5 mm 2 vs VBT 0.7 ± 0.7 mm 2, P = .043), the lumen dimensions revealed no difference between groups at follow-up (DES 6.5 ± 2.3 mm 2 vs VBT 6.8 ± 2.2 mm 2, P = .374). At the reference site, the index procedure led to a similar increase of plaque + media (DES 0.9 ± 0.9 mm 2 vs VBT 0.6 ± 1.2 mm 2, P = .150). At follow-up, the plaque + media was significantly smaller in the DES group (DES 8.0 ± 6.6 mm 2 vs VBT 9.9 ± 7.8 mm 2, P = .013). Drug-eluting stent for the treatment of ISR more effectively inhibits neointima formation when compared with VBT. Yet insufficient stent expansion might be a reason for device failure and should be avoided. At the reference site, lumen loss by an increased plaque burden, as has been well recognized following VBT, is not present with DES.