Clinical Comparison of Coronary Flow Reserve and Fractional Flow Reserve after PTCA in Patients with Coronary Artery Disease

Park, Keum Soo; Kwan, June; Seo, Jeong Kee; Hong, Eui Soo; Cho, Seong Wook; Lee, Woo Hyung

Abstract

OBJECTIVES
Severity of coronary artery stenosis has been defined in terms of geometric dimensions, pressure gradient-flow relations, resistance to flow and coronary flow reserve(CFR) after maximum arteriolar vasodilation. Myocardial fractional flow reserve(FFR) is a new index of the functional severity of coronary stenosis that is calculated from pressure measurements during coronary angiography. We compared the relationship between FFR and CFR after PTCA and the residual stenosis with FFR and CFR in the patients with acute myocardial infarction (AMI) and angina.
METHODS
The study population consisted of 25 patients with AMI and 18 patients with angina. All AMI patients had successful restoration of infarc-related artery by thrombolysis or direct PTCA. Doppler index was measured using 0.014 inch Doppler wire 15 minutes after successful restoration of infarc- related artery. Hyperemic index was measured after intracoronary injection of adenosine(16-18ug). Baseline and hyperemic distal coronary artery pressure was measured using 0.014 inch pressure wire with advancing the wire distal to the lesion and simultaneous proximal aortic pressure was measured using guiding catheter.
RESULTS
1) Post-interventional FFR and CFR were 0.91+/-0.09 and 1.87+/-0.45 in AMI and 0.93+/-0.06 and 2.73+/-0.67 in angina. There was no significant correlation between FFR and CFR in AMI and angina(p=NS). CFR showed the weak correlation with hyperemic distal pressure(hPd) in AMI(p=0.04) and FFR with hDSVR in angina(p=0.04). FFR and CFR were not correlated with mean blood pressure and heart rate(p=NS). 2) FFR and hyperemic pressure gradient had the close correlation with residual stenosis after successful PTCA in AMI and angina(p<0.001). Baseline pressure gradient also showed weak correlation with FFR(p<0.05). 3) CFR was 1.87+/-0.45 in AMI and 2.73+/-0.67 in angina with significant difference between two groups (p<0.001) and FFR was 0.91+/-0.09 in AMI and 0.93+/-0.06 in angina without difference(p=NS). hPa and hPd showed the significant difference between the two groups(p<0.05).
CONCLUSION
FFR seems to be a new index of the functional severity of coronary stenosis that is calculated from pressure measurements during coronary angiography.