Background: Cardiac troponins provide excellent risk stratification in unstable angina (UA), but no reliable markers are available in troponin-negative patients. Beta2-integrin mediated T cell recruitment plays a pivotal role in coronary atherosclerotic plaque rupture. The present study investigates beta2-integrin activation on T cell subsets as a risk marker in UA.
Methods: Functional activation (affinity/avidity) of beta2-integrins on T cells was measured using a flow cytometry-based whole blood assay in 87 patients with UA.
Results: Beta2-integrin activation was significantly higher in patients with severe coronary artery disease (sC) and myocardial infarction (MI) compared to patients with no/minimal coronary atherosclerosis (no/mC), irrespective of troponin status. Adjusted for cardiovascular risk factors, medication, left ventricular function, MI at enrollment and high sensitivity C-reactive protein (hsCRP), beta2-integrin activation was independently associated with incidence of revascularization, hospitalization and all major cardiovascular events during 9 months of follow-up after index investigation. The highest prognostic value of beta2-integrin activation was seen in troponin-and hsCRP-negative patients.
Conclusion: Quantitative assessment of T cell beta2-integrin activation allows to identify high risk patients with UA and sC without established MI; furthermore, it is associated with incidence of future cardiovascular events independent of conventional risk factors (troponin, hsCRP).