308 Corrected TIMI frame count correlates with stenosis severity and predicts functional improvement after percutaneous coronary intervention

Abstract

Introduction: The corrected TIMI frame count (cTFC) has been shown to be an index of coronary flow. Tissue Doppler imaging (TDI) can detect early ventricular dysfunction not detected by conventional methods. We hypothesize that: 1. TDI can detect abnormal regional function in non infarcted but chronically hypoperfused myocardium, 2. Improved cTFC post percutaneous coronary intervention (PCI) is associated with early functional improvement. Methods: Twenty nine patients (M/F: 19/10, age 67±9 years) with stable angina, and without prior myocardial infarction underwent cardiac catheterization, during which wall motion analysis (centerline method), quantitative coronary angiography (QCA) and CTFC (using a frame counter on a cine viewer) were measured. All patients had a standard 2-D and Doppler echocardiography and Pulsed wave TDI of systolic (Sm) and diastolic velocities (early: Em, late: Am) from the perfusion territories of the left anterior descendens (LAD), the circumflex (CX) and the right coronary artery (RCA), using the apical views, before and 24 hours after PCI. Results: All patients underwent elective PCI (19 LAD, 4 CX and 6 RCA stenoses, range 61 94%). There was TIMI grade 3 flow before and after PCI. Regional wall motion (centerline method and wall motion score with echocardiography) was normal in all patients before and after PCI. Significant improvement in the following parameters was observed post PCI (mean ± SD): QCA, 72±12% to 8±6%; cTFC, 35±19 to 22±8; Sm, 5.4±1.1 to 8±1.4; p < 0.005 for all. An improvement was also seen in diastolic function E/A ratio from 0.87±0.23 to 0.97±0.2. A significant correlation was found between cTFC and stenosis severity pre PCI (r=0.58, p=0.0028), and the improvement in cTFC and the regional Sm values post PCI (r = 0.79, p<0.0001). Multiple regression analysis showed that only improvement in the cTFC was important in predicting regional functional recovery within 24-hours post PCI (p=0.0005). In conclusion, TDI could detect regional abnormal function in non infarcted but hypoperfused myocardium, which was undetected by conventional methods. The cTFC correlates with stenosis severity, and that improvement in cTFC (coronary flow) predicts early functional recovery after PCI.