This study was a historical cohort in a single cardiovascular center to evaluate the incidence of major adverse cardiac and cerebrovascular events (MACCE) in patients with diabetes and multi-vessel coronary disease.
We recruited all the patients from a main cardiovascular data base of Ekbatan hospital, Hamadan, Iran. The proposal of this study was according to the ethical standards of 1964 Helsinki Declaration and approved by the ethics committee of Ekbatan Hospital. We included in this study every patient with diabetes and multi-vessel coronary disease, undergoing elective revascularization by CABG or PCI from July 2009 (when for the first time PCI was available in our center by interventional cardiologists) to March 2012. We excluded patients with poor prognosis, such as those with malignancy, cardiogenic shock, acute myocardial infarction during 24 hours before revascularization, concomitant valve surgery, and previous CABG or PCI; and those with anatomical problems, such as atrial septal defect, ventricular septal defect, and mitral valve sever regurgitation. Thus, we had 572 patients with diabetes (patients with at least 1 FBS>126 mg/ dlit or positive history of diabetes at the time of index admission. All patients signed informed consent to undergo CABG and PCI. Because the study was retrospective, we were unable to obtain informed consent from those patients in whom MACCE occurred, we also obtained informed consent waiver from the same ethics committee.
PCI and CABG
Decision-making about the revascularization strategy was done after consult with surgical services, with attention to the patient's preference. Patients with complex diseases, such as LAD involvement, multivessel disease, sever left ventricular dysfunction, and diabetes, were referred for CABG. Also, PCI with DES stents (drug eluting stent) in patients with diabetes was preferred over bare metal stents (BMS). PCI was often achieved with femoral approach of the Seldinger technique. All patients in the PCI group received 300 mg clopidogrel and 325 mg aspirin during 24 hours before the intervention. In-group cardiac enzymes and electrocardiograms were checked during the first 24 hours after the intervention routinely.
In the CABG group, off pump CABG was preferred to on pump CABG and left internal mammary artery (LIMA). All patients were monitored for at least 72 hours after surgery at the intensive care unit and antiplatelet agents, such as aspirin and clopidogrel, were not administered 48 hours before surgery. After surgery, heparin was prescribed routinely for all patients.
Patients in the 2 arms of revascularization therapy (CABG or PCI) were advised to take 2 antiplatelet agents (aspirin and clopidogrel) postoperatively. The least time for consumption of antiplatelet drugs in patients with a DES stent was 12 months, for those with the BMS stent 6 months, for the CABG group 2 to 3 months.
During the first year after the index procedure, all patients were visited by clinicians at intervals of 1 to 3 months and the new occurrence of myocardial in fraction was assessed using electrocardiogram and history; and for the subsequent years, this visiting interval was adjusted by clinicians taking into account the patient’s condition.
Clinical Outcomes and Follow-up
The outcome in this study was MACCE, including non-fetal myocardial infarction (MI), cardiac death, cerebrovascular accident (CVA), and target vessel revascularization (TVR). We assessed the occurrence of MACCE based on the information provided by telephone contact and hospital readmission and clinical records. If the follow-up was impossible, it was considered as loss to follow-up. Diagnose of cardiac death was based on the main cause of death registered on the death certification and other clinical events determined by the attendance. Cerebrovascular events were defined as strokes and transient ischemic attacks. Post procedural medical treatment was assessed via telephone interviews. By the end of the study time those who did not experience any outcome were considered as censored.
The values are presented in mean ± standard deviation, which were compared using an independent t test and frequency, which are tested using the χ^2 test for continuous and categorical variables, respectively. The cumulative clinical event rate during follow-Up at 1 and 3 years in CABG and PCI groups were compared using the log-rank test. After performing a propensity score matching for reducing any selection bias, a Cox proportional hazards regression model was applied to find the significant predictors of MACCE. After determining the best model according to the presence or absence of the predictors based on the Akaike Information Criterion using the stepwise method, the proportionality of hazards was checked using Schoenfeld residuals.