title: Platelet reactivity and thrombogenicity in postmenopausal women.
abstract: OBJECTIVE
  Age-adjusted incidence of cardiovascular disease, including myocardial infarction, is significantly lower in premenopausal women than in men, which is thought to be caused by the cardioprotective effects of estrogen. However, there is a consistent increase in the incidence of coronary artery disease in postmenopausal women in comparison with premenopausal women. The protective benefit of hormone therapy has not been observed in postmenopausal women. It is unknown whether measures of platelet reactivity and clot strength contribute to the disproportionate incidence of cardiovascular disease between premenopausal and postmenopausal women.
  
  
  METHODS
  Fifty healthy volunteers, including 25 premenopausal women and 25 postmenopausal women, aged between 40 and 65 years were enrolled. Total estradiol and follicle-stimulating hormone levels were measured for confirmation of menopausal state and comparison testing. Platelet reactivity was assessed using light transmission aggregometry and P-selectin, and glycoprotein IIb/IIIa receptor expression was assessed using flow cytometry. Thrombelastography was used to measure clot strength, clotting time, and fibrinogen activity. Serum cholesterol, C-reactive protein, complete blood count, and comprehensive metabolic panel were also measured.
  
  
  RESULTS
  Platelet reactivity did not differ among menopausal states or hormone levels. Clotting time was increased in postmenopausal women (6.6 ± 2.0 vs. 7.8 ± 1.2 min, P = 0.013) and significantly correlated with estradiol levels (r = 0.68, P < 0.001). A significantly higher low-density lipoprotein cholesterol level was observed in postmenopausal women (P = 0.05). Mean C-reactive protein levels were numerically higher in the postmenopausal group.
  
  
  CONCLUSIONS
  The thrombotic risk profile between premenopausal and postmenopausal women is similar. However, improved management of cholesterol may be of clinical benefit. Large-scale studies are required to validate these findings.
authors.affiliation: Sinai Center for Thrombosis Research, Baltimore, MD, USA.
authors.forename: Anand
authors.initials: A
authors.lastname: Singla
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Bliden
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Jeong
authors.forename: Katrina
authors.initials: K
authors.lastname: Abadilla
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Antonino
authors.forename: William C
authors.initials: WC
authors.lastname: Muse
authors.forename: Denny P
authors.initials: DP
authors.lastname: Mathew
authors.forename: Oscar
authors.initials: O
authors.lastname: Bailon
authors.forename: Udaya S
authors.initials: US
authors.lastname: Tantry
authors.forename: Paul A
authors.initials: PA
authors.lastname: Gurbel
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000502:physiology*; D002097:C-Reactive Protein / Q000032:analysis; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D039661:Integrin beta3 / Q000097:blood; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood; D010974:Platelet Aggregation; D040201:Platelet Membrane Glycoprotein IIb / Q000097:blood; D017698:Postmenopause / Q000502:physiology*; D012307:Risk Factors; D013927:Thrombosis / Q000453:epidemiology*
chemical_list: D008078:Cholesterol, LDL; D039661:Integrin beta3; D019007:P-Selectin; D040201:Platelet Membrane Glycoprotein IIb; D004958:Estradiol; D005640:Follicle Stimulating Hormone; D002097:C-Reactive Protein; D002784:Cholesterol