Clinical Investigations Does Exercise-Induced Severe Ischemia Result in Elevation of Plasma Troponin T Level in Patients with Coronary Artery Disease?

It has been reported that a loss of cell-membrane integrity during severe ischemia results in elevation of plasma troponin T (TnT) in unstable angina. W e investigated whether TnT is released into circulation during severe ischemia (e.g. on treadınili exercise testing) in patients with chronic coronary artery disease (CAD). The study comprised 54 patients who had angiographically documented CAD (22 patients had prior myocardial infarction) and 18 normal subjects. All cases underwent exercise TI- 201 SPECT myocardial perfusion imaging. Blood samples were obtained before, immediately after and 6 hours after exercise for TnT measurements. SPECT images were divided into 20 segments. Patients with 2:5 redistribution defects were considered to have severe ischemia. 16 patients had severe ischemia on SPECT images. The mean TnT were 0.009±0.10, 0.012±0.009, 0.010±0.010 ng/ml in patients with severe ischemia and 0.014±0.009, 0.010±0.009, 0.010±0.009, 0.010±0.010 ng/ml in normal subjects before, immediately after and 6 hours after exercise, respectively. There was no signifıcant difference between the 2 groups and also in pre-, post-exercise TnTs in each group. All TnTs were normal ( <0.1 ng/ml). Additionally, when the patients were grouped according to other SPECT variables (patients with reversible defects vs. patients with fıxed defects; patients with increased lung TI-201 uptake vs. patients without those; patients with transient ischemic dilatation vs. without those) and angiographic findings (patients with multivessel disease vs. normal subjects), there was no significant differe nce in pre-and postexercise TnTs. In conclusion, severe ischemia does not result in elevation of plasma TnT !eve! in patients with CAD.