Background: The effect of β-radiation on extra-stent vascular remodeling in patients with in-stent restenosis has not been studied. The correlation between the extent of extra-stent plaque proliferation and that of intimal hyperplasia (IH) in in-stent restenosis in patients who received β-radiation therapy as well as conventional therapy has also not been studied. Methods: We evaluated the extra-stent remodeling in diffuse in-stent restenosis between a β-radiation therapy patient group ( 188Re-MAG3, n=50) and a control group (n=9) by applying serial intravascular ultrasound (IVUS) analysis. Matching (post-intervention and follow-up) images were acquired at the follow-up lesion site and were available in 44 of 50 patients who received radiation therapy and in seven of nine control patients. Results: There was a significant increase of the external elastic membrane (EEM) area in both groups: 16.4±3.3 mm 2 post-intervention to 17.1±3.3 mm2 at follow-up, P=0.001 in the radiation therapy group, and 16.8±4.0 mm2 post-intervention to 17.4±4.1 mm2 at follow-up, P=0.008 in the control group. There were no statistically significant differences of the Δ EEM area between the two groups: 0.7±0.4 mm2 in the radiation therapy group vs. 0.6±0.4 mm2 in the control group, P=0.389. The Δ IH area correlated with the Δ EEM area in the control group (r=0.826, P=0.022), but not in the radiation therapy group (r=0.016, P=0.919). Conclusions: The findings of this IVUS study were that positive remodeling (increased EEM area) occurred equally in both control and irradiated patients with in-stent restenosis. The extent of remodeling was directly in proportion to IH in the control group, but no such relationship existed in the irradiated patient group.
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine