Abstract 9852: T Lymphocyte Depletion Following Primary Percutaneous Coronary Intervention Predicts Infarct Size and Ischemia Reperfusion Injury
Background: We have previously demonstrated acute changes in lymphocyte numbers in peripheral blood following reperfusion with primary percutaneous coronary intervention (PPCI) for STEMI. The goal of this study was to investigate a potential role for T cells in ischemia reperfusion (I/R) injury.
Methods: We analyzed blood from 22 STEMI patients undergoing PPCI. Blood was taken at the start of the procedure, and at 15, 30, 90 minutes, and 24 hours post reperfusion. In 5 patients with infarcts due to LAD occlusion, coronary sinus (CS) blood was also obtained 30-60min after reperfusion along with simultaneous aortic blood. 8-colour flow cytometric analysis was performed on the fresh blood to quantify lymphocyte populations. Cardiac MRI was performed at 1-7 days, and left ventricular ejection fraction, infarct size (measured by late gadolinium enhancement), microvascular obstruction (MVO), area at risk and salvage index quantified.
Results: T-lymphocytes dropped between 0 and 90 minutes by a mean of 42% (0min mean 1767/μl, 90min 931/μl), CD4 T-helper cells by 31%, and CD8 cytotoxic T-cells by 55%. The change in total T-cells correlated with infarct size (r=-0.78, p<0.001), as did that of CD4 (r=-0.66, p<0.01) and CD8 T cells (r=-0.76, p<0.001).
The T cell drop between 0 and 90 minutes also correlated strongly with MVO (r=-0.72, p<0.01), as did the CD4 (r=-0.66, p<0.01) and CD8 T cell drop (r=-0.77, p<0.001). Myocardial salvage index correlated strongly with the change in T cells (r=0.85, p<0.001), CD4 T cells (r=0.76, p<0.01) and CD8 T cells (r=0.76, p<0.01) between 30 and 90 minutes.
Prior to reperfusion 6.4% of CD8 T cells were activated (CD69+), with progressive loss of CD69+ cells after 90 minutes (4.3%) and 24 hours (2.6%, 0min vs 24hr p<0.01). However, CS sampling showed an increase in CD69 expression between aortic and CS blood, suggesting activation of T cells as they pass through the myocardial vascular bed.
Conclusion: Acute changes in T lymphocyte numbers following reperfusion after PPCI predict infarct size, MVO, and salvage index. The drop in these cells following reperfusion, and the dynamics of CD69 expression, suggest a potential role for CD69+ activated T cells in I/R injury. This requires further investigation and may represent a novel therapeutic target.
- © 2013 by American Heart Association, Inc.