THROMBOLYSIS IN MYOCARDIAL-INFARCTION FRAME COUNT IN SAPHENOUS-VEIN GRAFTS

Background Although the Thromboysis in Myocardiol Infarction flow grad e system is a widely used index of coronary blood flow, it has importa nt limitations. We recently described a new continuous measure of bloo d flow in native coronary arteries, the Thrombolysis in Myocardial Inf arction frame count (TFC), and sought to extend this method to coronar y artery bypass grafts. Methods We retrospectively analyzed cinefilms of patients' status after coronary artery bypass grafting, excluding p atients with recent myocardial infarction and grafts with stenoses in the graft or native vessel. We counted the cineframes required for dye to travel from the ostium of the graft to the graft anastomotic site (TFCg) and to a standardized distal coronary landmark (TFC). Results F or all vein grafts combined, TFCg was 19.2 +/- 5.7 frames (mean +/- SD , n = 93) and the TFC was 33.9 +/- 8.0 frames (n = 67). The upper limi ts for ''normal'' flow, calculated from the 95% confidence intervals, were 31 frames for TFCg and 50 frames for TFC. Conclusions The Thrombo lysis in Myocardial Infarction frame counting method has now been exte nded to normal saphenous vein grafts, and normal reference values are provided.