Variability of coronary flow reserve obtained immediately after coronary angioplasty

Coronary flow reserve (CFR) improves in most patients immediately following coronary angioplasty (PTCA). The degree of improvement, however, may be variable and its predictive value for a favorable long-term angiographic result is unknown. To evaluate these issues, we used digital subtraction angiography to measure CFR in 15 patients before and immediately after PTCA. Minimum coronary diameter improved and percent diameter stenosis was reduced immediately following PTCA (from 0.75 +/- 0.35 mm to 2.19 +/- 0.56 mm, and from 74 +/- 12% to 27 +/- 15%, respectively; p less than 0.001). While CFR improved in patients immediately following PTCA (from 1.49 +/- 0.75 to 2.68 +/- 1.73; p less than 0.05), a substantial variability in CFR measurements (range 0.80 to 8.33) was present. At repeat arteriography 2.9 +/- 0.6 months later, 4 patients demonstrated restenosis. Compared with the 11 patients without restenosis, those with restenosis had similar coronary dimensions and CFRs immediately following PTCA. We conclude that coronary flow reserve, determined by digital subtraction angiography, improves in most patients immediately after PTCA but the degree of improvement is variable. Its ability to predict long-term angiographic outcome remains uncertain.