Intravascular ultrasound (IVUS) is one of the golden standards for the assessment of optimal angioplasty. Pressure-derived myocardial fractional flow reserve (FFRmyo) is a lesion-specific functional index of epicardial conduit and may be particularly useful for the assessment of optimal coronary angioplasty. The purpose of this study was to assess IVUS parameters and FFRmyo after successful angioplasty on coronary angiogram and compare them between balloon and stent group.

The study population consisted of 28 patients who underwent revascularization (14 cases of balloon angioplasty only, 14 cases of angioplasty with stent) from Jan. 1999 to Aug. 2000 at Inha University Hospital. After successful angioplasty on coronary angiogram, we measured minimal luminal diameter (MLD), minimal luminal area (MLA), lesion area stenosis (l-AST) and reference area stenosis (r-AST) with IVUS imaging. And we calculated FFRmyo from the ratio of mean coronary pressure distal to the stenosis (Pd) to the aortic mean pressure (Pa) during maximum coronary hyperemia (Pd/Pa).

There was significant difference of MLD (2.2±0.4 vs 2.6±0.3), MLA (4.4±1.1 vs 6.4±1.7), r-AST (43.7±9.2 vs 29.8±9.4) and FFRmyo (0.89±0.07 vs 0.93±0.03) between balloon and stent group. All IVUS parameters (MLD, MLA, r-AST) are well correlated with FFRmyo after angioplasty (r=0.52, p<0.05, r=0.48, p<0.05 and r=-0.72, p<0.05 respectively). By multiple regression analysis, r-AST showed the best correlation with FFRmyo among IVUS parameters.

Coronary angioplasty with stent showed more favorable MLD, MLA, r-AST and FFRmyo than balloon angioplasty. FFRmyo may be seemed to be alternative to IVUS for estimating the result of coronary angioplasty.