title: Aspirin responsiveness safely lowers perioperative cardiovascular risk.
abstract: BACKGROUND
  Vascular surgeries are related to high cardiac morbidity and mortality, and the maintenance of aspirin in the perioperative period has a protective effect. The purpose of this study was to evaluate the association between preoperative platelet aggregability and perioperative cardiovascular (CV) events.
  
  
  METHODS
  A preoperative platelet aggregation test was performed on an impedance aggregometer in response to collagen and to arachidonic acid (AA) for 191 vascular surgery patients under chronic use of aspirin. We analyzed the following CV events: acute myocardial infarction, unstable angina, isolated troponin elevation, acute ischemic stroke, reoperation, and cardiac death. Hemorrhagic events were also evaluated and classified according to the Thrombolysis In Myocardial Infarction criteria.
  
  
  RESULTS
  The incidence of CV events was 22% (n = 42). Higher platelet response to AA was associated with CV events, so that patients in the fourth quartile (higher than 11Ω) had almost twice the incidence of CV events when compared with the three lower quartiles: 35% vs 19%; P = .025. The independent predictors of CV events were hemodynamic instability during anesthesia (odds ratio [OR], 4.12; 95% confidence interval [CI], 1.87-9.06; P < .001), dyslipidemia (OR, 3.9; 95% CI, 1.32-11.51; P = .014), preoperative anemia (OR, 2.64; 95% CI, 1.19-5.85; P = .017), and AA platelet aggregability in the upper quartile (OR, 2.48; 95% CI, 1.07-5.76; P = .034). Platelet aggregability was not associated with hemorrhagic events, even when we compared the lowest quartile of AA platelet aggregability (0-1.00 Ω) with the three upper quartiles (>1.00 Ω; OR, 0.77; 95% CI, 0.43-1.37; P = .377).
  
  
  CONCLUSIONS
  The degree of aspirin effect on platelet aggregability maybe important in the management of perioperative CV morbidity, without increment in the bleeding toll.
authors.affiliation: Interdisciplinary Medicine in Cardiology Unit, University of São Paulo Medical School, São Paulo, Brazil. Electronic address: daniela.calderaro@gmail.com.
authors.forename: Daniela
authors.initials: D
authors.lastname: Calderaro
authors.forename: Adriana Feio
authors.initials: AF
authors.lastname: Pastana
authors.forename: Tania Rubia
authors.initials: TR
authors.lastname: Flores da Rocha
authors.forename: Pai Ching
authors.initials: PC
authors.lastname: Yu
authors.forename: Danielle Menosi
authors.initials: DM
authors.lastname: Gualandro
authors.forename: Nelson
authors.initials: N
authors.lastname: DeLuccia
authors.forename: Elbio Antônio
authors.initials: EA
authors.lastname: D' Amico
authors.forename: Bruno
authors.initials: B
authors.lastname: Caramelli
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage*; D001938:Brazil / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D019990:Perioperative Care / Q000379:methods*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011183:Postoperative Complications; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014656:Vascular Surgical Procedures
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin