Platelet aggregation and cardiovascular events after vascular surgery

• Grant number: 09/16064-2
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2010
• End date: April 30, 2012
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Daniela Calderaro
• Grantee: Daniela Calderaro
• Host Institution: Instituto do Coração Professor Euryclides de Jesus Zerbini (INCOR). Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Major vascular surgeries are related to high morbidity and mortality, mainly due to myocardial ischemia. Besides the classical concept of imbalance in myocardial oxygen supply and demand, atherothrombosis is also present in perioperative myocardial infarction, justifying the protective effect of perioperative salicylic acid maintenance in patients under chronic prescription. Considering the great variability of individual response to standard salicylic acid prescription, the primary end-point of our study is to evaluate the association between platelet aggregability and perioperative cardiovascular events in vascular surgical patients under chronic use of salicylic acid. We are also going to evaluate the incidence of hemorrhagic events. Our secondary end-point is to evaluate platelet aggregability behaviour after surgery in the same population. This is a prospective and observational study, with 200 patients scheduled for elective major vascular surgeries and 30 patients with peripheral atherosclerosis not scheduled for surgical intervention. All patients are under chronic salicylic acid prescription. Platelet aggregation will be assessed in the day before and 2 days after surgery, by 2 quantitative methods: IMPACT-R(DiaMed-Switzerland) and impedance aggregometry (Chrono-log/USA). For the other 30 patients, platelet aggregation will be assessed twice (7 days interval), by the same methods. This control group will show us spontaneous variability in platelet aggregation. Every patient will be closed monitorized for early event detection, and we defined the following cardiovascular events until the 7-th pos-operative day or hospital discharge (the first to happen): acute myocardial infarction, unstable angina, isolated troponin elevation, stroke, death as cause of the previous cited events and vascular reoperation. Hemoglobin levels, transfusion and hemoorhagic events will be assessed. We will evaluate the statistical association between pre-operative platelet aggregability and perioperative cardiovascular events and we are going to compare the behaviour of this parameter in the perioperative X spontaneous setting (control group). If our hypothesis that patients with higher platelet aggregability have more perioperative cardiovascular complications is confirmed, we are going to have another tool for perioperative pharmacoprotection adjustment. (AU)