Effects Of Diabetes Mellitus On Arterial Stiffness And Structure And Function Of Heart

Objective and Background: Along with the development of society, the improvement of people's life and the change of life style, morbidity and mortality of diabetes mellitus are on the rise in which arterial stiffness plays an important role. As a signal of vasculopathy, arterial stiffness correlates with its development and prognosis. In contrast with hypertension, the change of aret arterial stiffness in diabetic patients attracts less attention, especially when they coexist. As a mark to test arterial stiffness, the use of pulse wave velocity (PWV) is widespread. Some study acknowledges that the elevation of PWV is an independent risk factor of cardiovascular death. In the present study, we intend to know the factors that influence baPWV and adopt it as an index to measure arterial stiffness so as to evaluate the effect of diabetes mellitus on arterial stiffness and heart structure and its function by measuring baPWV noninvasively.Methods: 188 persons were selected, either from outpatients or from subjects that want to have heath examinenation of cardiovascular department and endocrine department from December 2007 to December 2008. Their average age is 64±11(38～87)years, including 108 male and 80 female. They were separated into four groups, including 46 with hypertension, 33 with type 2 diabete mellitus, 79 with type 2 diabetes mellitus and hypertension, 30 healthy subjects. Hypertension and diabetes mellitus were in line with their correspnding diagnostic criterion. Patients such as secondary hypertension, type 1 diabetes, coronary heart disease, serious hepatopathy and nephrosis, infectious diseases, immunologic diseases, malignant tumor, Peripheral Angiopathies (ABI<0.9), stroke, valvular heart diseases, cardiomyopathy, arterial fibrillation and other arrhythmia,ejection fraction<50% and refusing to be measured were excluded. (1)For every participant,his/her data (such as history of past illness, history of smoking, history of taking medicine, et al)must be provided. After measuring the height and weight, brachial-ankle Pulse Wave Velocity(baPWV), Ankle-Brachial Index (ABI), systolic blood pressure(SBP), diastolic pressure(DBP), pulse pressure(PP), mean blood pressure(MAP)was measured by Automatic Arteriosclerosis Measurement System(BP-203RPEII); (2)Check the venous blood in the morning after fasting (>12 hours) to get the results of biochemical markers, such as triglyceride(TG), total cholesterol(TC), low density lipoprotein(LDL), high density lipoprotein(HDL), fast blood glocuse(FBG), uric acid(UA), creatinine(CR), and For the diabetic patients, HbA1C must be measured by an automatic biochemistry analyzer; (3)The cardiac parameters such as aortic dimension (AO), left atrial diameter(LA), left ventricle diastolic dimension (LVEDD), left ventricle systolic dimension(LVESD), interventricular septal thickness(IVS), left ventricle posterior wall thickness(LVPW), left ventricular mass index(LVMI), relative wall thickness(RWT), ejection fraction(EF), the peak velocity of early rapid filling(E), the peak velocity of late filling(A) were assessed by Doppler echo cardiograph (GE VIVID 7D). Once the data had be collected, they were analyzed by means of statistics software SPSS11. 5.Results: 1. There was no significant difference among the four groups, concerning age, sex, smoking, body mass index, TG, TC, LDL, HDL (P>0.05); Hypertensive group and hypertensive diabetic group had significantly higher SBP, DBP, PP, MAP compared to diabetic group and healthy control group(P<0.05), but there was no significant difference between them(P>0.05); Diabetic and hypertensive diabetic groups had apparently higher FBG than hypertensive group and diabetic group(P<0.05) but there was no significant difference in fast blood glucose (FBG)and glycosylated hemoglobin(HbA1C) between them.There was no difference in UA among the three sick groups(P>0.05) but they had higher UA than healthy control group(P<0.05).2. For all the subjects, there was an apparent correlation of bilateral baPWV(r=0.957, P=0.00), so we analyzed the data by the mean baPWV. The highest baPWV(2841.5cm/s) was observed in patients with hypertension and diabetes mellitus and the lowest baPWV(901.0cm/s)was observed in healthy control group. The sick groups had higher baPWV than healthy control group(P<0.05). The hypertensive and diabetic group had significantly higher baPW than other sick groups(P<0.05). There was no significant difference in ABI among the four groups (P>0.05).3. The three sick groups had higher LA and A but lower E and E/A than healthy control group(P<0.05)and diabetic and hypertensive group had significantly higher LA and A but lower E and E/A than hypertensive group and diabetic group(P<0.05)but There was no difference between the latter two groups(P<0.05); Hypertensive group had higher LVMI than other groups(P<0.05)but there was no difference among the sick groups(P>0.05).4. For all the subjects, a multivariate stepwise regression demonstrated that SBP, age, and UA were independent factors that affected baPWV(P<0.05).5. For all the diabetic patients ,there was a positive relation between baPWV and history of hypertension, the course of diabetes mellitus, age, HbA1C, UA, SBP, DBP, PP, MAP and A(P<0.01) but baPWV had a negative association with E/A (r=-0.266, P<0.01); baPWV had no relation with LA, LVEDD, LVESD, IVS, LVPW, LVMI, RWT and E(P>0.05); There were no relationship between baPWV and the history of smoking, sex, BMI, TC, TG, HDL, LDL and CR(P>0.05); Regarding the correlative variates as independent variables and baPWV as dependent variable, a multivariate stepwise regression demonstrated that SBP, age, HbA1C and UA were independent factors that affected baPWV(P<0.05).Conclusion: 1. Hypertensive patients and diabetic patients have faster baPWV than the health control group and Diabetic and hypertensive patients has faster baPWV than the former two sick groups. This conclusion indicate that diabetic patients and hypertensive patients had different impairment of large blood vessels and it is especially worst in diabetic and hypertensive patients.2. Age, SBP, UA and HbA1C are independent factors that affect baPWV for the patients with diabetes mellitus .For the diabetic patients we may regard UA and HbA1C as the predictors of arterial stiffness.3. BaPWV has negative correlation with E/A; The elevated baPWV prompts the increase of arterial stiffness and the decrease of diastolic function of heart in patients with hypertension, diabetes mellitus or diabetes mellitus and hypertension. BaPWV can assess the diastolic function of heart to a certain extent.4. The arterial stiffness of diabetic patients is raised and Diabetes mellitus mainly has obvious effect on the diastolic fountion of heart; When diabetes mellitus and hypertension are concurrent, they aggravate the progress of arterial stiffness and the damage of the structure and function of heart.