Early Lumen Loss After Treatment of In-Stent Restenosis

Abstract

Background —Mechanisms of recurrence after treatment of in-stent restenosis are unknown. Methods and Results —We prospectively performed quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) in 37 lesions with Palmaz-Schatz stents enrolled in a study of intracoronary radiation for in-stent restenosis. Primary treatment was at the discretion of the operator: PTCA (n=8) or ablation+adjunct PTCA (n=29). Lesions were studied before intervention, immediately after primary intervention, and 42±8 minutes later. QCA measurements included minimal luminal diameter and diameter stenosis. Planar IVUS measurements included arterial, stent, lumen, and in-stent tissue areas. Stent, lumen, and in-stent tissue volumes were calculated by use of Simpson’s rule. Compared with immediately after intervention, the delayed (42±8 minutes) minimal lumen area decreased by 20% (5.8±1.9 to 4.5±1.3 mm 2 , P <0.0001) and the lumen volume by 12% (58±41 to 52±37 mm 3 , P =0.0001). Ten lesions (27%) had a ≥2.0-mm 2 decrease in minimum lumen area. Lumen loss (1) resulted from increased tissue with the stent, (2) correlated with lesion length and preintervention in-stent tissue, and (3) was not seen angiographically. Conclusions —There is significant tissue reintrusion shortly after catheter-based treatment of in-stent restenosis. This was greater in longer lesions and those with a larger in-stent tissue burden, was not reflected in the QCA measurements, and may contribute to recurrence.