Differential Impact of Stent versus PTCA on Restenosis in Large (≥3 mm) and Small

Abstract

To determine the impact of reference vessel size on restenosis (RES) in the multicenter randomized STent REStenosis Study (STRESS), we compared stent (S) vs PTCA in large (≥3 mm by ImageComm quantitative angiographic edge detection methods) and small (<3 mm) vessels. S ≥ 3mm(kanni)N = 102 PTCA≥3(kanni) mmN = 90 S<3 mm(kanni)N = 102 PTCA <3 mm(kanni)N = 111 Final % stenosis 20 ± 10 34 ± 11 † 17 ± 13 36 ± 17 † Acute gain (mm) 1.86 ± 0.44 1.39 ± 0.52 † 1.58 ± 0.44 1.10 ± 0.40 † Late loss (mm) 0.71 ± 0.58 0.38 ± 0.60 0.78 ± 0.55 0.49 ± 0.53 ** Net gain (mm) 1.11 ± 0.62 0.98 ± 0.65 0.85 ± 0.59 0.63 ± 0.53 * RES (>50% stenosis) 25.6 28.9 35.6 52.4 * * p < 0.05 ** p < 0.001 † p < 0.0001 compared PTCA with S For large and small vessels, S (compared to PTCA) had greater acute gain due to lower final % stenosis but S also had greater late loss. Nevertheless, net gain was still greater in S pts resulting in lower RES (vs PTCA). Late angiographic responses to S and PTCA were different in large and small vessels; S had similar late loss irrespective of vessel size, whereas PTCA had less late loss in ≥3 mm vessels which partially neutralizes the acute gain benefit of S. Thus, although RES was generally lower in ≥3 mm vessels, there was little difference among S and PTCA pts. In <3 mm vessel, absolute RES was higher and there was a marked difference in RES between S and PTCA. Importantly, late clinical events showed a similar differential response; target lesion revascularization (CABG or repeat PTCA) was similar for S and PTCA in ≥3 mm vessels (15 vs 13%, NS) but in <3 mm vessels was lower in S pts (22 vs 32%, P = 0.1). Data from STRESS indicate that S had a greater impact on lowering RES and increasing clinical benefit in smaller <3 mm) vs larger (≥3 mm) vessels. Future designs efforts should be directed towards developing a smaller S which can be safely implanted in smaller coronary vessels.