title: Platelet activation increases in patients undergoing vascular surgery.
abstract: BACKGROUND
  Platelets are a major contributor to atherothrombosis and may contribute to the heightened risk of perioperative cardiovascular events. We sought to examine changes in platelet activity in subjects undergoing vascular surgery.
  
  
  METHODS
  Platelet activity in 18 patients (median age 74, 45% female) undergoing non-emergent open vascular surgery was assessed by light transmission aggregometry in response to saline, epinephrine and adenosine-5 diphosphate (ADP), and by flow cytometric analysis of monocyte-platelet aggregation (MPA). Platelet activity was assessed preoperatively (T1), 1-hour into the operation (T2), 1-hour (T3), 24-hours (T4) and 48-hours post-operatively (T5). Data were compared using the Wilcoxon Signed Ranks Test. Continuous variables are summarized as medians and (interquartile, IQR) ranges.
  
  
  RESULTS
  Spontaneous platelet aggregation increased transiently during the surgical period (T1-5.8% [2.4, 10.8], T2-13.5% [9.3, 26.5], T3-7.5% [3.3, 17], T4-10.0% [7.3, 16.3], T5-7.25% [4.5, 29.9], P=0.002). Similar trends in perioperative platelet activity were noted for platelet aggregation in response to epinephrine (P=0.035) and ADP (P=0.036). Using flow cytometry, we found an increase in MPA during the perioperative period (P=0.047), which was most significant between T1 and T3 (P=0.005).
  
  
  CONCLUSIONS
  Platelet activity increases significantly during and following open vascular surgery. This data may help explain the pathophysiology of increased thrombotic risk during the perioperative period of vascular surgery.
authors.affiliation: Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY.
authors.forename: Gabriel S
authors.initials: GS
authors.lastname: Schneider
authors.affiliation: Department of Surgery, Division of Vascular Surgery, New York University School of Medicine, New York, NY.
authors.forename: Caron B
authors.initials: CB
authors.lastname: Rockman
authors.affiliation: Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY; Department of Surgery, Division of Vascular Surgery, New York University School of Medicine, New York, NY; Department of Medicine, Division of Hematology, New York University School of Medicine, New York, NY. Electronic address: jeffrey.berger@nyumc.org.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Berger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000166:cytology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period; D015539:Platelet Activation; D010974:Platelet Aggregation; D010979:Platelet Function Tests; D013927:Thrombosis / Q000097:blood / Q000209:etiology*; D014656:Vascular Surgical Procedures / Q000009:adverse effects*