Abstract 11265: Different Outcomes According to Platelet Aggregation Level in Vascular Surgery
PURPOSE Maintenance of aspirin in the perioperative period of vascular surgery is recommended. Considering the great variability of response to aspirin and the need to identify higher risk patients, our purpose is to evaluate the association between pre-operative platelet aggregability and perioperative cardiovascular events.
METHODS This is a prospective study with vascular surgery patients under chronic aspirin use. Platelet aggregation was assessed by impedance aggregometry before surgery. Patients were monitorized until hospital discharge for detection of cardiovascular(CV) events: myocardial infarction,unstable angina,troponin elevation,stroke,cardiac death and vascular reoperation.
RESULTS We evaluated 191 patients submitted to abdominal aortic aneurysm repair,peripheral revascularization or carotid procedures and 42 patients had an event(22%). Patients in the higher quartile of platelet aggregation for 0.5mmol/L of arachidonic acid (aggrAA>11 Ω) had almost twice CVevents than patients in the others quartiles:35% X18.54%;P=0.025.In the logistic regression model adjusted for the CVrisk according to the American College of Physicians guidelines,aggrAA > 11 Ω (OR 2.48; CI 1.07 - 5.76, P=0.034), anemia (OR 2.64; CI 1.19 - 5.85, P=0.017), dislipidemia (OR 3.90; CI 1.32 - 11.51, P=0.014) and hemodynamic instability during anesthesia (OR 4.12; CI 1.87 - 9.06, P<0.001) were identified as independent predictors of CVevents.Importantly, platelet aggregation was not related to hemorrhagic events (HE), even when we tested the lowest quartile of aggrAA (58.41% X 51.32%; P = 0,336). The predictors of HE were open surgery (OR 1.66; CI 1.14 - 1.77, P=0.016), current smoking status(OR 5.05; CI 1.74 - 14.67, P=0.003), anemia(OR 0.43; CI 0.20-0.89, P= 0.024), creatinine elevation > 1.5X baseline(OR 3.28; CI 1.23 - 8.77, P= 0.018) and hemodynamic instability during anesthesia(OR 3.41;CI 1.53 - 7.59,P= 0.003).
CONCLUSION Patients with higher platelet aggregability stimulated by arachidonic acid have more CV complications and patients with lower platelet aggregability do not have more hemorrhagic complications after vascular surgery. We believe that platelet aggregation tests might be a tool for pharmacoprotection adjustment.
- © 2012 by American Heart Association, Inc.