The Clinical Symptoms And Target Organ Damage Of The Elevation Of Blood Pressure In Normotensive Subjects With Baseline Hypotensive Status

BackgroundPrevious studies about hypotension at home and abroad showed that the proportion of hypotension is higher in women than men, mostly young women. One study about the prevalence of hypotension in Chinese people in 2001 revealed that the total prevalence of hypotension in women was 7.36%, which was significantly higher than men whose prevalence was 2.7%. Besides, the prevalence of hypotension is on the decline with increasing of age. Hypotension can be divided into physiological hypotension and pathological hypotension. Physiological hypotension means that the person who doesn’t suffer from ischemia and hypoxia in spite of hypotension, and it doesn’t pose a threat to life. The phenomenon was mainly seen in young women. Some scholars even thought that these young women with physiological hypotension had a better prognosis as the lower blood pressure load imposed on cardiovascular system. And the lower blood pressure load may lead to lower risk of cardiovascular events and higher survival rate.As we all known that the vascular elasticity decreased with increasing of age, which leads to the elevation of blood pressure. So the prevalence of hypertension was higher in aged. The Global Burden of Disease Study 2010 showed that raised blood pressure (systolic>115 mm Hg) is the biggest single risk for death and disability, leading to 9.4 million deaths each year. It is estimated that 45% of heart disease and 51% of stroke being caused by increased blood pressure. And the burden of blood pressure related disease had become one of the major public health problem in China as it seriously do harm to health and causes heavy economic burden. The 2013 ESH/ESC guidelines for the management of arterial hypertension defined and classified of office blood pressure levels was that optimal blood pressure (systolic blood pressure<120mmHg and diastolic blood pressure<80mmHg), normal blood pressure (systolic blood pressure 120-129mmHg and/or diastolic blood pressure 80-84mmHg), high normal blood pressure (systolic blood pressure 130-139mmHg and/or diastolic blood pressure 85-89mmHg), hypertension (systolic blood pressure >140mmHg and/or diastolic blood pressure>90mmHg). Now, most studies had confirmed that hypertension is the main risk factors of cardiovascular disease and can lead to serious cardiovascular events. In addition, recently some research found that blood pressure continues relate to the risk of cardiovascular disease. And high normal blood pressure had been confirmed a high risk factor of developing to hypertension and cardiovascular events. Furthermore, prehypertension (systolic blood pressure 120-139mmHg and/or diastolic blood pressure 80-89mmHg) also been considered as risk factor of developing to hypertension and cardiovascular events. So the reasonable and earlier management and preventive strategies are urgently needed to reduce the occurrence of related clinical cardiovascular disease.As mentioned above, whether the lower blood pressure load leads to lower risk of cardiovascular events and higher survival rate in physiological hypotension person is still unknown. And now we didn’t see the related study about long-term follow-up in physiological hypotension person. While during our clinical work, we observed some high normal blood pressure or normal blood pressure subjects experiment some symptoms analogous to hypertension, such as dizziness, headache, neck stiffness, chest tightness, palpitation. Besides, these symptoms improved along with lowering-blood pressure in a certain extent after a period of non-pharmaceutical therapy (aerobic exercise, low salt diet and good sleeping et al). According to the history of disease we know that these persons are low blood pressure during youth (18-35 years old). So here we want to investigate the clinical significance and target organ damage of the elevation of blood pressure in high normal blood pressure or normal blood pressure subjects with baseline hypotensive status.Objective1. To investigate the correlation of clinical symptom and blood pressure in high normal blood pressure or normal blood pressure subjects with baseline hypotensive state.2. To evaluate target organ damage in high normal blood pressure or normal blood pressure subjects with baseline hypotensive state compared with high normal blood pressure or normal blood pressure subjects with baseline normotensive state and high blood pressure subjects with baseline normotensive state.3. To assess whether the elevation of blood pressure can be used as an evaluation index in the management of blood pressure.Subjects1.65 high normal blood pressure or normal blood pressure subjects with baseline hypotensive state were enrolled, named Nonno-Hypo group. Besides, we divided the Nonno-Hypo group into two subgroups according to the level of 90/60 mmHg. Group A is that the systolic blood pressure less than or equal to 90 mmHg during youth. Group B is that the systolic blood pressure 91-98 mmHg during youth. Inclusion criteria:(1) The chief complaint was symptoms analogous to hypertension. (2) The blood pressure was high normal blood pressure or normal blood pressure. (3) These persons were physiological hypotension during youth (18-35 years old). (4) The blood pressure didn’t increase rapidly in a short period of time. (5) Except for other disease which can cause these symptoms.2.90 normal blood pressure subjects with baseline normotensive state were screened, named Normo-Normo group. Inclusion criteria:(1) No history of high blood pressure and high blood pressure medication. (2) The blood pressure was matched for Normo-Hypo group. (3) These persons were not physiological hypotension during youth (18-35 years old).3.79 high blood pressure subjects wifh baseline normotensive state were included, named Hyper-Normo group. Inclusion criteria:(1) Newly diagnosed hypertension or prior diagnosed hypertension. (2) These persons were not physiological hypotension during youth (18-35 years old).Methods1. To test the relationship between clinical symptoms and blood pressure in Normo-Hypo group.Repeated measure blood pressure when high normal blood pressure or normal blood pressure subjects with baseline hypotensive state suffered from clinical symptoms; Observing the clinical symptoms and blood pressure after a period (3-12 month)of non-drug therapy; Then observing the clinical symptoms and blood pressure again after stop non-drug therapy for a period; Last observing the clinical symptoms and blood pressure again after restart non-drug therapy.Lowing blood pressure measurement:Non-drug therapy. Like dietary restriction, exercise, adjust the mental pressure, good sleep, quit smoking, drinking little.2. To examine the blood pressure and target organ among three groups.2.1 Office blood pressure measurementOffice blood pressure was measured using mercury sphygmomanometer. After the participants had rested in the sitting position for 15 minutes,3 consecutive blood pressure readings were obtained according to the recommendations of the European Society of Hypertension. For analysis, the 3 readings were averaged.2.2 Arterial stiffness measurementArterial stiffness was measured using bosoABI-system100 (Germany) to examine brachial-ankle pulse wave velocity (baPWV) and ankle brachial index (ABI). Patients were examined in the supineposition after resting for at least 5min. Pressure waveforms of the brachial and tibial arteries were recorded by an oscillometric method using occlusion/sensing cuffs applied to both arms and both ankles. The higher baPWV of two arms was used.2.3 EchocardiographyM-mode,2-dimensional echocardiography was performed with Philips iE33, equipped with multiple frequency-phased array transducers (l-5MHz). Left ventricular end-diastolic dimension, interventricular septum thickness and left ventricular posterior wall thickness were measured. LV mass was calculated and indexed to body surface area (LVMI).2.4 Carotid ultrasoundCarotid ultrasound to access IMT and plaque was performed with a Philips IU22 device equipped with a 5-11 MHz high-resolution linear transducer.2.5 Biochemical indexVenous blood was collected after a minimum 12h of overnight fasting, were analyzed by automated enzymatic methods for fasting plasma glucose, total cholesterol, triacylglycerol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, serum creatinine, blood urea nitrogen and uric acid.3. Statistical analysisFor database management and statistical analysis, we used the SPSS20.0 and GraphPad prism 5.0. Data were expressed as means±SD. Difference between means were examined using t test or ANOVA for normally distributed variables. We determined differences in target organ damage among three groups from generalized linear models. Chi-squared was performed to describe categorical variables. Pearson correlation was used to assess univariate associations. Statistical significance was assumed if the null hypothesis could be rejected at P＜0.05.Results1. The relationship between clinical symptoms and blood pressure in Normo-Hypo group.1.1 clinical symptoms:The main symptom was dizziness,58 patients suffered from dizziness. And the next were headache and neck stiffness,37 patients suffered from headache and 23 patients suffered from neck stiffness.1.2 Blood pressure:In Normo-Hypo group, the mean blood pressure was 90.3±4.2/58.6±3.5mmHg in patients when they were young, and it was 127.1±5.1/73.6±8.1 mmHg when they had one or more symptoms. The mean elevation of BP was 36.8±6.0/15.0±8.5 mmHg. Additionally, the symptoms significantly improved with BP decreased at 8.4±3.0/5.0±3.2 mmHg by non-drug therapy. And there was significant difference between blood pressure before and after therapy (SBP:127.1±5.1 vs 118.8±3.8, P＜0.001; DBP:73.6±8.1 vs 68.7±6.3, P<0.001).2. The elevated blood pressure among three groupsThe elevated blood pressure in Normo-Hypo group and Hyper-Normo group were significant higher than Normo-Normo group (SBP:36.8±6.0 vs 22.3±5.2, P＜0.001,42.6±9.6 vs 22.3±5.2, P＜0.001; SBP:15.0±8.5 vs 10.7±5.9, P＜0.01, 28.4±11.3 vs 10.7±5.9, P＜0.001). Besides, the elevated blood pressure in Hyper-Normo group was higher than Normo-Hypo group. Furthermore, the subgroup in Normo-Hypo group showed that the elevated systolic blood pressure in group A was higher than group B.3. Target organ damage among three groups3.1 baPWV and ABI:BaPWV in Hyper-Normo group was significant higher than Normo-Hypo group and Normo-Normo group (14.97±2.0 vs 13.50±1.5, P<0.001; 14.97±2.0 vs 12.73±1.0, P<0.001). Besides, baPWV in Normo-Hypo group was higher than Normo-Normo group (P＜0.05). There is no difference about ABI among three groups.3.2 IMT:IMT in Normo-Hypo group and Hyper-Normo group were higher than Normo-Normo group (0.94±0.19 vs 0.84±0.14, P＜0.01; 0.97±0.20 vs 0.84±0.14, P＜0.001). In addition, there is no difference between Normo-Hypo group and Hyper-Normo group.3.3 LVMI:LVMI in Hyper-Normo group was higher than Normo-Normo group (98.7±26.5 vs 86.2±14.5, P＜0.001). There is no difference about LVMI in Normo-Hypo group compared with other two groups (91.4±15.6 vs 86.2±14.5, P>0.05; 91.4±15.6 vs 98.7±26.5, P＞0.05).3.4 The subgroup in Normo-Hypo group showed that the vascular damage in group A was more serious than group B.4. Correlations between the elevated blood pressure and target organ damage index4.1 baPWV:In the whole group of subjects, baPWV was related to the elevated systolic blood pressure(r=0.41, P＜0.01), the elevated diastolic blood pressure(r=0.37, P<0.01) and pulse pressure(r=0.51, P＜0.01). In Normo-Hypo group, baPWV was related to the elevated systolic blood pressure(r=0.51, P＜0.01), the elevated diastolic blood pressure(r=0.23, P=0.033) and pulse pressure(r=0.21, P=0.045).4.2 IMT:In the whole group of subjects, IMT was related to the elevated systolic blood pressure(r=0.33, P＜0.01), the elevated diastolic blood pressure(r=0.26, P＜0.01). The relation between IMT and pulse pressure didn’t reach the statistical significance (P=0.085). In Normo-Hypo group, IMT was related to the elevated systolic blood pressure(r=0.32, P＜0.01), the elevated diastolic blood pressure(r=0.31, P＜0.01). The relation between IMT and pulse pressure didn’t reach the statistical significance (P=0.37).4.3 LVMI:In the whole group of subjects, LVMI was related to the elevated systolic blood pressure(r=0.37, P＜0.01), the elevated diastolic blood pressure(r=0.27, P＜0.01). The relation between IMT and pulse pressure didn’t reach the statistical significance (P=0.24). In Normo-Hypo group, IMT was related to the elevated systolic blood pressure(r=0.44, P＜0.01). The relation between IMT and the elevated diastolic blood pressure and pulse pressure didn’t reach the statistical significance (TSBP, P=0.30:PP,P=0.44).Conclusion1. The patients in Normo-Hypo group had some symptoms analogous to hypertension when the blood pressure below 140/90mmHg. And we test that these symptoms were significantly related to blood pressure.2. The patients in Normo-Hypo group had target organ (cardiac and vascular) damage. There is seriously vascular damage and slightly impaired LV function in subjects with Normo-Hypo.3. The elevated blood pressure was related to baPWV, LVMI and IMT. And the elevated systolic blood pressure was more obviously related to target organ damage. This indicated that the elevated blood pressure may play an important role in the development of target organ damage.4. These clinical symptoms and elevated blood pressure may be used as an effective index to start the management of blood pressure in patients with Normo-Hypo.