The Evaluation of Arterial Early Damage in High-normal Blood Pressure Population
|School||Dalian Medical University|
|Keywords||High-normal blood pressure Augmentation index arteriosclerosis|
Background and objective: Hypertension, as a major risk factor of cardiovascular and cerebrovascular diseases, has always been concerned. The blood pressure is shown as a continuous unimodal distribution. There is no sharp dividing line between hypertension and normotension. The diagnostic criterion of hypertension is stipulated based on the findings of a large number of epidemiology. There has been widespread concern over the range of people whose blood pressure are lower than the cut point of hypertension has been concerned by some researchers. The concept of pryhypertension which was proposed by The Guidelines of the Joint National Committee for the seventh time reported by The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure in 2003, while its definition was emphasized by the American college of Cardiology after the TROPHY study. But this concept was changed into high-normal blood pressure by The European Society of Hypertension and the European Society of Cardiology in order to avoid panic and over-medicine. With the proposal of high-normal blood pressure, doctors and patients are reminded to pay more attention not only to the blood pressure of 140mmHg and (or) 90mmHg but also to the range of systolic blood pressure of 130-139mmHg and diastolic blood pressure of 85-90mmHg. Previous studies have showed that in high normal blood pressure already exist the decrease of arterial elasticity, endothelial dysfunction, changes of vascular structure and function, which play a crucial role in the occurrence and development of hypertension, and even in the occurrence and development of cardiovascular diseases. What’s more, optimal, normal, and high-normal blood pressure might progress to hypertension over time respectively, but the three risk are quite different. In the Framingham Heart Study, the progression rates to hypertension over a 4-year period were 5%, 18%, and 37% for theyounger(aged 35 to 64 years) groups with optimal, normal, and high-normal blood pressure, and 16%, 26%, and 50% for the older (aged 64 to 94 years) groups respectively. Clinical trial data from patients with high-normal blood pressure showed that 40% over 2 years and 63% over 4 years developed hypertension. There are several potential reasons for progression to hypertension in individuals with high-normal blood pressure. First, individuals with high-normal blood pressure require a smaller increment of blood pressure on follow-up to progress to hypertension than the other groups. Second, risk factors for hypertension are twice more common in the high-normal blood pressure group. Therefore, to emphasize the primary prevention of hypertension, and then prevent and reduce the incidence of cardiovascular disease and even mortality, it is of great significance to detect arteriosclerosis and vascular disfunction at an early stage. However, these detections have been applied among hypertensives, and the data are almost about hypertensive patients. There are a few date about the evaluation of arteriosclerosis, endothelial disfunction and the of artery in high-nomal blood pressure population.As a newly-developed technology, AI has been applied in a large amount of large-scale clinical studies. AI can evaluate the elasticity of the whole arterial system. The reflection of pulse wave can be demonstrated followed the change of aorta and arteriole. The theory of pulse wave analysis was applied in AI. Because avoiding the affect of blood pressure, AI was paid more and more attention in the evaluation of arteriosclerosis. In addition, it owns convenient operation. Amount of researches showed AI is a useful index in evaluation of cardiovascular risk and prediction factor of cardiovascular incident. Two formulae have always been used. The formula of AI=(the second peak systolic blood pressure (SBP2)-diastolic blood pressure (DBP))/(the first peak systolic blood pressure (SBP1)-diastolic blood pressure (DBP))×100% was applied in this research. At present, there is no report about detection of arterial elasticity among high-normal blood pressure population. RadialAI was detect and the result was analysised to talk over the damage of the high-normal blood pressure population and provide evidence of early intervention. Methods: Health examinees were recruited in medical examination center in the First Affiliated Hospital of Dalian Medical University, which include 1414 cases of effective samples. In the meanwhile, individuals with serious arrhythmia, heart failure, diabetes, secondary hypertension, severe liver, kidney, pancreas disease, history of stroke, chronic wasting disease, cancer, and other serious disease were excluded. According to the criterion of ESH/ESC, the subjects were divided into normal blood pressure, high-normal blood pressure, hypertension. Radial AI from HEM 9000AI produced by Omron is applied to detect subjects in comfort situation. Meanwhiles, venous blood was phlebotomized to detect total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, creatinine, uricum acidum, urea nitrogen, fasting blood glucose. Statistical process and analysis were performed using Statistical Package for Social Science 11.5 for windows software and EXCEL 2003. One-way analysis of variance were used to statistical the different between the three groups. Covariance was used to analysis the difference among the three groups after other factors were adjusted. Numerical correlations were established by a Person correlation. Any association between rAI75 and other factors were tested by calculating bivariate Pearson’s correlation coefficients. Stepwise multiple linear regression models were applied to assess what the factors of rAI75 are.Results:1. rAI75 of female is higher than male’s in any decades.2. After adjusting other factors, rAI75 of the three groups is still different. However by comaprison between every two groups, the result is obtained that rAI75 in high-normal blood pressure group is significantly higher than that in normal blood pressure, the rAI75 of hypertension group is higher than both high-normal blood pressure and normal blood pressure group.3. rAI75 is related to age, height, gender, DBP, and heart beat rate.4. Age,gender,height,DBP,and heart beat rate are major influence factor of rAI75.Conclusion:1. rAI75 is gradually increased among normal blood pressure, high-normal blood pressure, and hypertension. People with high-normal blood pressure already have early damage of artery.2. AI can be used as a mean of screening the early damage of artery. It can be used to evaluate the risk factor among group with high-risk of cadiaovascular, and even among the group of high-normal blood pressure with comparatively low-risk.3. People with high-normal blood pressure will be subjects need early intervention to prevent cardiovascular events.