To investigate whether cardiopulmonary bypass (CPB)-induced platelet dysfunction is associated with dysregulated autophagic flux in patients undergoing cardiac surgery.

Prospective, single-center observational study.

A tertiary university hospital cardiac operating room.

Forty adult patients undergoing cardiac surgery with CPB.

No therapeutic intervention was applied. Blood samples were collected at 3 perioperative time points for platelet function and autophagy assessment.

Platelet count (PLT) significantly decreased after CPB, whereas mean platelet volume (MPV) was lower at T3 than at T1. Flow cytometry showed a marked increase in CD62P expression, and thromboelastography revealed a significant reduction in maximum amplitude, indicating impaired platelet function. Western blotting and immunofluorescence demonstrated blocked autophagic flux, characterized by abnormal accumulation of both LC3-II and p62 in platelets.

Cardiac surgery with CPB is associated with platelet activation and functional decline, which are correlated with blocked autophagic flux.