Authors: Sergey Altarev, Yulia Podaneva and Olga Barbarash
Objective: Determine efficacy and safety of prolonged antiplatelet therapy before coronary artery bypass grafting (CABG) in patients with different body mass index (BMI).
Methods: We analyzed the data of the CABG Registry which had been carried out in the Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russian Federation, in 2009. The Registry contains the data of all the patients undergone CABG in the Institute in 2009 and includes demographic information, physical examination and laboratory test results, CABG records, data on preoperative and postoperative treatment and postoperative events. In order to conduct this study we divided the study population into two groups according to BMI: group 1 with BMI <25.0 kg/m2 and group 2 with BMI ≥25.0 kg/m2. The efficacy of different preoperative antithrombotic strategies was defined as the difference in postoperative ischemic event rates between the groups. Ischemic events included myocardial infarctions and ischemic strokes. The safety of different preoperative antithrombotic strategies was defined as the difference in postoperative bleeding event rates between the groups. Bleeding events included both minor and major bleeding. Binary data were presented as counts and frequencies. Contingency tables of the 2х2х2 type were analyzed with a log-linear analysis. All the statistical calculations were performed using SPSS for Windows, version 13.0 (SPSS Inc.). A p value <0.05 was considered statistically significant. Results: 757 patients were included in the Registry, of those 160 (21%) were in group 1. In 543 (66%) cases antiplatelet therapy was stopped more than 5 days before CABG (‘early’ withdrawal). All demographic, anamnestic and clinical data of the above-mentioned group was comparable to the data of the patients who had antiplatelet therapy stopped 5 or more days before surgery (group of early antiplatelet withdrawal). In order to evaluate efficacy and safety of prolonged antiplatelet therapy we made tables of the 2х2х2 type. It was shown that the rate of early postoperative bleeding events was similar in the groups and subgroups of patients and had limits from 6% to 9% (G2=4, df=4, р=0.38). The rate of postoperative ischemic cerebral and cardiovascular events was the highest in patients with BMI <25.0 kg/m2 and early antiplatelet withdrawal (14%), and, in another subgroups, it was no more than 3% (G2=32, df=4, р<0.001). Conclusion: Prolonged antiplatelet therapy before CABG is safe independent of BMI and prevents more ischemic cerebral and cardiovascular events in patients with low or normal BMI than in patients with high BMI. Keywords: CABG, antiplatelet therapy, BMI, coronary artery bypass, body mass index