Coronary artery bypass graft surgery up-regulates genes involved in platelet aggregation


Per Tornvall, Department of Medicine, Cardiology Unit, Karolinska University Hospital Solna, Karolinska Institutet, Stockholm 171 76, Sweden.
Tel.: +46 8 517 729 51; fax: +46 8 517 729 51.


Summary.  Background:  During and shortly after coronary artery bypass graft (CABG) surgery, there is an increase in thromboembolic events. CABG, a strong inflammatory stimulus, is associated with a hypercoaguable state. Platelets might contribute to this hypercoaguable state because they have a pivotal role in thrombosis. In the days following surgery there is augmented platelet regeneration in response to the inflammatory stimulus.

Objectives:  The aim of this study was to investigate any changes in platelet mRNA profiles to test the hypothesis that post-CABG surgery platelets are associated with a prothrombotic state.

Methods:  Blood was sampled and platelets purified from 11 patients before and 3–6 days after CABG. Gene expression profiling was performed using low density array (LDA) plates for seven of the patients.

Results:  Forty-five genes were examined and those significantly up-regulated were glycoprotein (GP)IIb, GPIIIa and cyclooxygenase-1 (COX-1). These findings were confirmed in four more patients, including flow cytometry analysis of the GPIIb/IIIa receptor.

Conclusions:  CABG surgery up-regulates mRNA and protein levels of proteins that are key players in platelet aggregation. Marked elevation of GPIIb/IIIa mRNA levels results in significantly increased GPIIb/IIIa expression in platelets post-CABG surgery, which may be a reason for increased thrombus formation and myocardial infarction after CABG.