Thrombolysis in Myocardial Infarction Frame Count for Coronary Blood Flow Evaluation during Interventional Diagnostic Procedures

Background and Objectives: An interventional diagnostic procedure (IDP), including intracoronary acetylcholine (ACh) provocation and coronary physiological testing, is recommended as an invasive diagnostic standard for patients suspected of ischemia with no obstructive coronary arteries (INOCA). Recent guidelines suggest Thrombolysis In Myocardial Infarction frame count (TFC) as an alternative to wire-based coronary physiological indices for diagnosing coronary microvascular dysfunction. We evaluated trajectories of TFC during IDP and the impact of ACh provocation on TFC. Materials and Methods: This was a single-center, retrospective study. Patients who underwent IDP to diagnose INOCA were included and divided into two groups according to the positive or negative ACh provocation test. Wire-based invasive physiological assessment was preceded by ACh provocation tests and intracoronary isosorbide dinitrate (ISDN). We evaluated TFC at three different time points during IDP; pre-ACh, post-ISDN, and post-hyperemia. Results: Of 104 patients, 58 (55.8%) had positive ACh provocation test. In the positive ACh group, resting mean transit time (Tmn) and baseline resistance index were significantly higher than in the negative ACh group. Post-ISDN TFC was significantly correlated with resting Tmn (r = 0.31, p = 0.002). Absolute TFC values were highest at pre-ACh, followed by post-ISDN and post-hyperemia in both groups. All between-time point differences in TFC were statistically significant in both groups, except for the change from pre-ACh to post-ISDN in the positive ACh group. Conclusions: In patients suspected of INOCA, TFC was modestly correlated with Tmn, a surrogate of coronary blood flow. The positive ACh provocation test influenced coronary blood flow assessment during IDP.

The relationship between triglyceride/high-density lipoprotein cholesterol ratio and coronary slow-flow phenomenon

In this study, we aimed to investigate the relationship between high triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio and coronary slow flow phenomenon (CSFP) in patients undergoing elective coronary angiography for suspected coronary artery disease. This prospective study included a total of 84 CSFP patients and 83 controls with normal coronary flow, as evidenced by coronary angiography. The Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was used to measure the coronary blood flow velocity. The lipid profiles were analyzed and TG/HDL-C ratio were calculated dividing absolute TG levels by absolute HDL-C levels in peripheral blood. The median TG/HDL-C ratio was higher in the CSFP group than the control group (3.4 [2.6 to 4.9] vs. 2.3 [1.8 to 3], respectively; p < 0.001). The multivariate logistic regression analysis revealed that TG/HDL-C ratio was an independent predictor of CSFP (odds ratio [OR] 1.78, 95% confidence interval [CI] 1.59-2.32; p = 0.001) and TG/HDL-C ratio was positively correlated with the TFC in the CSFP group (r = 0.311, p < 0.001). The area under the receiver operating characteristic curve of TG/HDL-C for the diagnosis of CSFP was 0.73 (95% CI 0.65-0.81; p < 0.001). If a cut-off value of 2.75 was used, higher levels of TG/HDL-C ratio could predict the presence of CSFP with 72% sensitivity and 71% specificity. Our study results suggest that TG/HDL-C ratio is associated with CSFP and may be a useful biomarker for predicting CSFP and its severity.