Early Lumen Loss After Treatment of In-Stent Restenosis An Intravascular Ultrasound Study

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 mm2, P<0.0001) and the lumen volume by 12% (58±41 to 52±37 mm3, P=0.0001). Ten lesions (27%) had a ≥2.0-mm2 decrease i...