title: Hypercoagulability affecting early vein graft patency does not exist after off-pump coronary artery bypass.
abstract: OBJECTIVE
  Hypercoagulability may compromise the patency of bypass grafts. The authors hypothesized that perioperative in vitro platelet responses to varying agonists (eg, thrombin, platelet activating factor, collagen, adenosine diphosphate) correlate with early graft thrombosis after off-pump coronary artery bypass grafting (OPCAB).
  
  
  METHODS
  Prospective study of 78 OPCAB patients with 151 venous bypass grafts treated with perioperative aspirin and intraoperative heparin (250 U/kg).
  
  
  METHODS
  Tertiary, academic medical center.
  
  
  METHODS
  None.
  
  
  RESULTS
  Hypercoagulability, defined by TEG (maximum amplitude [MA]>70 mm), whole-blood aggregometry (>15 ohms after 5 mcl/mL collagen) or hemoSTATUS (Ch5CR>0.5), was serially assessed around OPCAB. An immediate decline in platelet function after surgery and on postoperative day 1 returned to normal by postoperative day 3 in most patients. Graft blood flow was analyzed intraoperatively, and vein biopsies were analyzed for endothelial disruption. Graft patency was assessed by multichannel computed tomography coronary angiography on postoperative day 5. No differences in any of the platelet function assays were noted for the 8 patients with graft thrombosis (n=8 grafts) versus the 68 patients with all patent grafts (n=129 grafts). Ten patients developed a rise in platelet function postoperatively >1 SD above baseline; only 1 developed graft thrombosis (p=not significant v patients with normal platelet function).
  
  
  CONCLUSIONS
  OPCAB is not associated with a significant activation in postoperative platelet function. This study suggests that if hypercoagulability exists after OPCAB, it is not involved in the pathogenesis of arterial thrombotic events such as early bypass graft failure.
authors.affiliation: Department of Surgery, Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. rposton@smail.umaryland.edu
authors.forename: Robert
authors.initials: R
authors.lastname: Poston
authors.forename: Junyan
authors.initials: J
authors.lastname: Gu
authors.forename: James
authors.initials: J
authors.lastname: Brown
authors.forename: James
authors.initials: J
authors.lastname: Gammie
authors.forename: Charles
authors.initials: C
authors.lastname: White
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Manchio
authors.forename: Richard N
authors.initials: RN
authors.lastname: Pierson
authors.forename: Bartley P
authors.initials: BP
authors.lastname: Griffith
authors.forename: Paul
authors.initials: P
authors.lastname: Gurbel
authors.forename: Udaya
authors.initials: U
authors.lastname: Tandry
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Gilbert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000592:standards; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects; D005260:Female; D006083:Graft Occlusion, Vascular / Q000503:physiopathology / Q000517:prevention & control*; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012501:Saphenous Vein / Q000637:transplantation*; D019851:Thrombophilia / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology*; D019737:Transplants / Q000009:adverse effects; D014654:Vascular Patency / Q000502:physiology
chemical_list: D006493:Heparin; D001241:Aspirin