The value of the TIMI frame count method in the diagnosis of coronary no-reflow: a comparison with myocardial perfusion SPECT in patients with acute myocardial infarction

The state of no-reflow (i.e. inadequate myocardial tissue perfusion despite normal arterial flow proven in angiography after pharmacological or mechanical interventions) is considered to be a marker of a poor prognosis. Although the Thrombolysis in Myocardial Infarction (TIMI) flow grade is a valuable and widely used qualitative measure in angiography trials, it is limited by its subjective and categorical nature. Recently, the TIMI frame count method (TFC) was proposed for detecting no-reflow. In our study we aimed to compare TFC values with myocardial perfusion single photon emission computed tomography (SPECT) findings to investigate the additional role of the former method in the evaluation of no-reflow. Twenty patients (16 men and four women; mean age 58+/-9 years) with first acute myocardial infarction were included in the study after thrombolytic therapy. Coronary angiography (CAG) was performed 5-7 days later. The TIMI flow grade and TFC values were determined in angiography examinations. A TIMI flow of less than grade 3 and a TFC value >27 were considered to be pathologically decreased for coronary artery blood flow. Tc tetrofosmin myocardial rest SPECT was carried out 24 h after coronary angiography. SPECT images were scored on a four-point scale in 20 myocardial segments and the total defect score was calculated from the sum of defect scores in 20 segments. Wall motion was assessed using the wall motion score index in echocardiography (ECWSI). The occurrence rates of angiographic no-reflow, pathological TFC and perfusion defects in SPECT were calculated as 40% (8/20), 47% (8/17; non-measurable in three patients with TIMI grade 0), and 55% (11/20), respectively. Perfusion defects were present and the TIMI frame count value was increased in all patients with angiographic no-reflow (TIMI grade <3). The occurrence rate of perfusion defects and increased TFC was equal (42%) in all 12 patients having TIMI grade 3 flow. Increased TFC was demonstrated in four of five patients having perfusion defects and TIMI grade 3 flow (80% compatibility with SPECT). TIMI frame count and ECWSI values were significantly higher in patients having perfusion defects than in patients with normal perfusion ( <0.05). It is concluded that the TIMI frame count is a valuable method in the detection of patients with TIMI grade 3 flow, with no-reflow, and increases the specificity of coronary angiography in the evaluation of the response to thrombolytic therapy. A pathologically increased TFC value with TIMI grade 3 flow during CAG seems to be a good indication for the use of myocardial perfusion SPECT in the definitive diagnosis and/or follow-up of such patients.