Background: Myocardial ischaemia in patients with end-stage renal disease (ESRD) develops both due to the epicardial coronary artery stenosis and to the microvascular injury. We aimed to evaluate coronary blood flow in ESRD patients by means of the thrombolysis in myocardial infarction (TIMI) frame count method (TFC). In patients with ESRD, implementation of the TFC as a marker of the coronary flow abnormalities have not been previously investigated.
Methods: Thirty-nine ESRD patients on regular dialysis underwent elective coronary angiography. Coronary artery stenosis >75% was defined as significant. TFC for the three main coronary vessels was calculated. Higher TFC values reflected slower flow.
Results: In 19 patients (49%), significant epicardial coronary artery disease was found. Distribution of the TFC for the three main coronary arteries reflected prevalence for higher TFC values. Mean corrected TFC for the left anterior descending artery (LAD) was 34.7 +/- 16, for the circumflex artery (Cx) 41.5 +/- 25 and for the right coronary artery (RCA) 30.9 +/- 18 frames. For the three main coronary vessels, there were no statistically significant differences between the mean TFC values according to the presence or absence of the severe coronary artery stenoses on angiography (LAD: 30.2 +/- 12 vs 36.3 +/- 18; Cx: 41.5 +/- 20 vs 41.5 +/- 27; RCA: 34.9 +/- 16 vs 30.0 +/- 19, respectively).
Conclusions: Our results demonstrate for the first time the reduction in blood flow velocity, assessed with TFC method, in the coronary arteries of ESRD patients. This phenomenon was observed regardless of the presence of the significant epicardial coronary artery stenosis. Therefore, TFC cannot be applied as a marker of significant coronary artery stenosis in ESRD population.