Predictive value of the corrected TIMI frame count in patients with suspected angina pectoris but no obstructive coronary artery disease at angiography

Abstract

To evaluate whether the corrected thrombolysis in myocardial infarction frame count (CTFC), an index of resting coronary blood flow, is associated with the risk of major adverse cardiovascular events (MACE) in patients with suspected stable angina pectoris (SAP) but no obstructive coronary artery disease (CAD) at angiography. In this case-control study, CTFC at baseline in 127 patients (50 % women) who subsequently experienced a myocardial infarction, non-hemorrhagic stroke or cardiovascular death during 2001-2011 was compared with CTFC in 254 event-free matched controls. All patients had suspected SAP but no obstructive (≥50 % stenosis) CAD at baseline angiography. Mean CTFC in controls was 23.4 (95 % confidence interval 20.9-25.9) frames and mean CTFC in cases did not differ significantly with a difference of -1.0 (-3.1 to 1.1) frames (P = 0.35) and no sex-specific interaction (P = 0.18). In a conditional logistic regression model, we found no dose-response relationship between CTFC and the risk of MACE, i.e., compared to the risk in the lowest CTFC quintile, the odds ratios for MACE were 1.3 (0.7-2.6), 0.7 (0.3-1.3), 0.7 (0.4-1.5) and 1.0 (0.5-2.1) in the second, third, fourth and fifth CTFC quintiles, respectively. Adjustment for cardiac risk factors including diabetes, active smoking, body mass index, and use of lipid-lowering and antihypertensive medication did not significantly change the results. In patients with SAP symptoms without obstructive CAD at angiography, CTFC is not associated with the risk of MACE.