Differential Impact of Stent versus PTCA on Restenosis in Large (≥3mm) and Small <3mm) Vessels in the STent REStenosis Study

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 (≥3mm by ImageComm quantitative angiographic edge detection methods) and small (<3mm) vessels.S≥3mm(kanni)N=102PTCA≥3(kanni)mmN=90S<3mm(kanni)N=102PTCA <3mm(kanni)N=111Final % stenosis20±1034±11†17±1336±17†Acute gain (mm)1.86±0.441.39±0.52†1.58±0.441.10±0.40†Late loss (mm)0.71±0.580.38±0.600.78±0.550.49±0.53**Net gain (mm)1.11±0.620.98±0.650.85±0.590.63±0.53*RES (>50% stenosis)25.628.935.652.4**p<0.05**p<0.001†p<0.0001 compared PTCA with SFor 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 ≥3mm vessels which partially neutralizes the acute gain benefit of S. Thus, although RES was generally lower in ≥3mm vessels, there was little difference among S and PTCA pts. In <3mm 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 ≥3mm vessels (15 vs 13%, NS) but in <3mm vessels was lower in S pts (22 vs 32%, P=0.1).In conclusionData from STRESS indicate that S had a greater impact on lowering RES and increasing clinical benefit in smaller <3mm) vs larger (≥3mm) vessels. Future designs efforts should be directed towards developing a smaller S which can be safely implanted in smaller coronary vessels