The Time And Safety Of An Oral Glucose Tolerance Test Performed On Patients With Acute Coronary Syndrome

Objective: Type 2 diabetes is a major risk factor for cardiovascular morbidity and mortality. In patients with diabetes mellitus, 55% have coronary artery disease. Diabetic patients with cardiovascular disease are 2 to 4 times higher than non-diabetic peers in the risk of mortality in adults. Most patients with diabetes are died of cardiovascular disease before the age of 50. About eighty percent of patients with diabetes are died of cardiovascular disease, of which 3/4 of the patients are died of coronary heart disease, the others are died of cerebrovascular or peripheral artery disease. The main finding of the Euro Heart Survey on diabetes and the heart was that 70% of patients with coronary artery disease had abnormal glucose metabolism. While 1/3 of the patients knew their diabetes mellitus, the other proportion of patients with non-known abnormal glucose metabolism was diagnosed by OGTT detection. Without the use of OGTT, there were 15% of diabetes and 45% of impaired glucose tolerance that would have remained undiagnosed. The China Heart Survey found that the prevalence of patients with DM and impaired glucose regulation were 52.9% and 24.0% in patients with CAD, respectively. The total prevalence of abnormal glucose metabolism was 76.9%. If an OGTT was not performed, 87.4% of patients with impaired glucose regulation (IGR) and 80.5% of DM that would not detected by fasting plasma glucose detecting alone. Both the Euro Heart Survey and the China Heart Survey found that the frequency of disturbed glucose metabolism was considerably high in patients with CAD. The prevalence of abnormal glucose metabolism would be obviously underestimated by measuring FPG only. Evidence based management in acute and stable coronary artery disease seems to be at least as effective in diabetic as in non-diabetic patients with MI. A lot of clinical researches demonstrate that high blood glucose has a close relationship with coronary artery attack. Impaired glucose regulation, especially impaired glucose tolerance makes the risk of cardiovascular disease high, which is the major risk factor for diabetes, which increases the rate of both diabetes and cardiovascular morbidity and mortality. Early diagnose and intervention of high blood glucose actively may not only delay the process of diabetes, or convert to the normal blood glucose, but also decrease the rate of cardiovascular morbidity and mortality. OGTT easily discloses the glucose metabolic status and should be an excellent way to assess impaired glucose tolerance for patients with cardiovascular disease. Acute coronary syndrome is a common clinical syndrome, including unstable angina, non-ST segment elevation myocardial infarction and ST segment elevation myocardial infarction. It has a high risk of mortality and disability, which has been the number one killer of human being. As ACS patients'high blood glucose may have stress factor and some coronary artery accidents may be deduced by performing the OGTT, some researchers suggest patients with ACS should routinely perform GTT three months after discharge. But many patients are not taking it seriously in practice, which makes a poor compliance. As a result, there are a large number of patients with abnormal glucose metabolism remain un- diagnosed, which does great harm to patient's health. There is no report about the time and safety of OGTT performing on patients with ACS in China. This research is used to assess the time and safety of performing OGTT, according to the blood glucose status, the variation of ECG, hs-CRP and so on.Methods: 62 inpatients with ACS in the cardiology department of the Second Hospital of Hebei Medical University were consecutively recruited from July 2009 to October 2010. Patients with previously knew diabetes mellitus and newly diagnosed DM, are not admitted to perform oral glucose tolerance test, the other would take OGTT at a stable body-condition before discharge and three months later.According to the diagnostic criteria of 1999 WHO:Diabetes mellitus (DM): FPG≥7.0mmol / L (126mg/dl) or OGTT2hPG≥11.1mmol / L (200mg/dl); Impaired glucose tolerance (IGT): FPG <6.1mmol/ L (103mg/dl), OGTT2hPG 7.8-11.0mmol / L (140-199mg/dl);Impaired glucose regulation (IGR): FPG 6.1-6.9mmol/ L (103-125mg/dl), OGTT2 hPG 7.8-11.0mmol / L (140-199mg/dl).Impaired fasting glucose (IFG): FPG 6.1-6.9mmol/ L (103-125mg/dl), OGTT2 hPG <7.7mmol / L (139mg/dl).Normal glucose (NGT): FPG<6.1mmol/L (103mg/dl), OGTT2hPG <7.7mmol / L.The patients were divided into five groups, which were diabetes mellitus (DM), impaired glucose tolerance (IGT), impaired glucose regulation (IGR), impaired fasting glucose (IFG) and normal glucose regulation (NGT) . Then, the incidences of normal and abnormal blood glucose were computed. The variation of ST segment electric tension, hs-CRP and uncomfortable symptoms during OGTT were recorded. Continuous variables were expressed as the mean value±standard deviation, categorical variables were presented as proportions(%). Continuous variables of ST segment electric tension and hs-CRP were compared using paired t-test. A p value <0.05 was considered statistically significant.The data analysis was performed using SPSS version 16.0 statistical software.Result: All the 62 patients with acute coronary syndrome were asked to perform OGTT. 32 males and 30 females composed the 62-subject-group with a mean age of 58.30±10.28 years which included 51 patients with unstable angina (UA), and 11 patients with non-ST segment elevation myocardial infarction (non-ST MI). All subjects were asked to perform OGTT in a stable body-condition before hospital discharge and three months later. The first -time of OGTT was performed on the 62 subjects, of whom 18(29.03%)had diabetes mellitus(DM), 22(35.48%)had impaired glucose tolerance (IGT), 3(4.84%)had impaired glucose regulation (IGR), 2(3.23%)had impaired fasting glucose (IFG) and 17(27.42%)had normal glucose regulation (NGT) . According to the second–time OGTT, there were 16(25.80%)DM, 21(33. 87%)IGT, 2(3.23%)IGR, 2(3.23%)IFG and 21(33.87%)NGT. There were not significant differences between the results of first and second time OGTT(P>0.05).The levels of Hs-CRP, ST segment electric tension were not found significant differences between the two groups with 3.52±1.43mg/L, 3.56±1.41mg/L(P>0.05)and﹣0.13±0.13mv,﹣0.15±0.15mv(P>0.05) respectively. Among the 62 subjects, there were two peers with heart-burn, one peer with nausea when performing the OGTT and one peer with angina the next morning.Conclusion:1 A majority of patients with non-ST acute coronary syndrome was also with abnormal glucose metabolism. And it was practical to perform OGTT on ACS patient without previously known diabetes in a stable-body condition before hospital discharge.2 It was safe for patients with acute coronary syndrome to perform an OGTT in order to early diagnose and intervene in IGR, who had a stable condition before hospital discharge.