Analysis of digital subtraction coronary angiography for estimation of flow reserve in critical stenosis

To examine the accuracy of digital subtraction angiographic assessment of coronary flow reserve in critical coronary stenosis, time-density curve was obtained from digital subtraction coronary angiograms for myocardial region of interest. Time to peak contrast (TPC) and time constant of the washout exponential curve (T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty (PTCA). All patients had normal left ventricular ejection fraction(59±7%) and Tl^<201> myocardial image at rest. The values of TPC and T were significantly shortened from 5. 4±1.3 to 4.5±1.0 sec (p<0.02) and from 10.9±3.8 to 5.3±1.3 sec (p<0.001) after PTCA, respectively. However, in 9 of all patients TPC after PTCA showed approximately the same valued as those before PTCA. IN 5 experimental dogs with critical circumflex stenosis, coronary flow (CF