Influence of a pressure gradient distal to implanted bare-metal stent on in-stent restenosis after percutaneous coronary intervention.

BACKGROUND Fractional flow reserve predicts cardiac events after coronary stent implantation. The aim of the present study was to assess the 9-month angiographic in-stent restenosis rate in the setting of optimal stenting and a persisting gradient distal to the stent as assessed by a pressure wire pullback recording in the entire length of the artery. METHODS AND RESULTS In 98 patients with angina pectoris, 1 de novo coronary lesion was treated with a bare-metal stent. After stent implantation, pressure wire measurements (P(d)=mean hyperemic coronary pressure and P(a)=mean aortic pressure) were performed in the target vessel: (1) P(d)/P(a) as distal to the artery as possible (fractional flow reserve per definition); (2) P(d)/P(a) just distal to the stent; (3) P(d)/P(a) just proximal to the stent; and (4) P(d)/P(a) at the ostium. Residual abnormal P(d)/P(a) was defined as a pressure drop between P(d)/P(a) measured at points 1 and 2. Fractional flow reserve distal to the artery after stenting was significantly lower (0.88+/-0.21 versus 0.97+/-0.05; P<0.001), and angiographic in-stent binary restenosis rate was significantly higher (44.0% versus 8.1%; P<0.001) in vessels with a residual abnormal P(d)/P(a). Residual abnormal P(d)/P(a) (odds ratio, 4.39; 95% confidence interval, 1.10 to 18.16; P=0.034), reference vessel size (odds ratio, 0.17; 95% confidence interval, 0.04 to 0.69; P=0.013), and stent length (odds ratio, 1.11; 95% confidence interval, 1.03 to 1.21; P=0.009) were predictors of angiographic in-stent restenosis after 9 months. CONCLUSIONS A residual abnormal P(d)/P(a) distal to a bare-metal stent was an independent predictor of in-stent restenosis after implantation of a coronary bare-metal stent.