Research Of Spontaneous Baroreflex Sensitivity And Target-organ Damage In Hypertensive Patients

Purpose and significance: Hypertension is a common chronic disease,and the incidence rate is increasing year by year.Epidemiological survey in 2010 showed that the prevalence of hypertension in adults in China is as high as 33.5%.High blood pressure is the most important risk factor for cardiovascular and cerebrovascular diseases.Long-term high blood pressure or excessive blood pressure fluctuations can cause acute and chronic complications such as stroke,heart failure,myocardial infarction,and hypertensive nephropathy.It imposes a heavy burden on the family economy and national health insurance.Autonomic dysfunction and increased sympathetic activity are of great significance in the development of hypertension.Baroreflex sensitivity(BRS)is an important indicator for quantitative assessment of autonomic function.It is generally accepted that BRS can be used as a long-term predictor of cardiovascular risk.As computer technology advances,baroreceptor-heart rate reflexes are evaluated by analyzing spontaneous fluctuations in arterial pressure and heart rate.These methods are "spontaneous BRS," which has the advantages of simple operation,non-invasiveness,and low cost.Autonomic nervous function changes in patients with essential hypertension,and the autonomic nervous system plays an important role in the long-term regulation of hypertension.Increased intake of salt is closely related to hypertension,and abnormal activation of the sympathetic nervous system is one of the important mechanisms.At present,there are relatively few clinical studies on BRS and the early stage of disease,but animal studies have found that damage to baroreceptors can cause target organ damage such as heart,blood vessels,and kidneys.Therefore,it is of great significance to apply BRS to the disease management and life intervention process of hypertension.The purpose of this study was to investigate the changes in spontaneous baroreflex sensitivity in patients with essential hypertension and the relationship between spontaneous BRS and early target organ damage.Provides more clues for the early management of cardiovascular disease and provides more basis for the formulation of treatment decisions.Subjects:We enrolled 123 patients with essential hypertension who were admitted to the Department of Hypertension and Endocrinology at Daping Hospital in Chongqing from March 2017 to October 2017.There were 59 patients with hypertension(EH)and 64 patients with hypertension and type 2 diabetes(EH+DM).And 40 healthy volunteers were recruited as control group.Methods : The diagnosis of hypertension is based on the "Chinese Guideline of Prevention of Hypertension 2010".Diagnosis of type 2 diabetes is according to the 2013 version of "Guideline for the prevention and treatment of type 2 diabetes in China".Recruiting healthy volunteers by posting posters.No history of hypertension or diabetes was required,and the age ranged from 35 to 75 years,regardless of gender.Blood pressure and blood glucose were measured to exclude hypertension and diabetes.Totally 40 healthy volunteers were enrolled in the study.Exclusion criteria : secondary hypertension;previous history of severe cardiovascular and cerebrovascular disease;persistent atrial fibrillation or frequent ectopic beats;confirmed hyperthyroidism,hypothyroidism,hypercortisolemia,anxiety and depression;previous renal disease History or renal insufficiency;history of severe liver disease;type 1 diabetes;gestational diabetes;special type of diabetes;diabetes acute complications;repeated dizziness,orthostatic hypotension;pregnant or lactating women.Collect general information such as gender,age,height,body weight,smoking history,hypertension course and antihypertensive drug use history;collect fasting plasma glucose,HbA1 c,blood lipids,renal function,liver function,24-hour urine Biochemical,24-hour urinary microalbumin,echocardiography,carotidultrasound,and 24-hour dynamic electrocardiography;Spontaneous baroreflex sensitivity test: Subjects are required to live and work regularly.No tea or coffee is taken on the day of the examination.No smoking is performed 30 minutes before the examination;5 minutes of lying position information and 3 minutes of standing position information were collected by continuous finger pulse pressure measurement(Finometer,Finapres Medical systems,Netherlands).BRS,systolic pressure,diastolic pressure,and heart rate were calculated and derived using built-in software(Beatscope).SPSS 24 software was used for statistical analysis.Clinical and laboratory data were compared using independent sample t-tests and ANOVA.Receiver operating characteristic curve(ROC)was used to evaluate the reliability of the diagnostic method.The risk factors were analyzed using binary logistic regression analysis.P<0.05 was considered statistically significant.Results:1.Spontaneous BRS can reflect cardiovascular autonomic function.And the lying and standing BRS were significantly positively correlated with SDNN in the entire 24-hour recording(r = 0.518 and 0.492,P <0.01).2.Compared with the control group,lying and standing BRS were significantly lower in EH groups(P<0.01).And it depressed more when combined with diabetes.Lying BRS was negatively correlated with salt intake in patients with EH(r =-0.284,P = 0.036).This correlation also exists in patients with EH+DM(r =-0.314,P = 0.012).3.Patients with hypertension were divided into high salt intake group(?12g/d)and low salt intake group(<12g/d).In EH the lying BRS of the low-salt group was significantly lower than that in the high-salt group(8.41±0.58 vs 6.51±0.47 ms/mmHg,P=0.025).In all hypertensive patients(including those with diabetes),the BRS in the low-salt group was also significantly higher than in the high-salt group(7.39±0.43 vs.6.08±0.36 ms/mmHg,P=0.031).4.Hypertensives with albuminuria had significantly lower standing BRS than those with normal urinary albumin(3.53±1.66 vs 4.27±1.68 ms/mmHg).5.Both lying and standing BRS in hypertensives with carotid atherosclerosis were lower than patients with normal carotid artery(lying: 6.27±3.26 vs 8.19 ±3.34;standing: 3.53±1.89 vs 4.60±1.52ms/mmHg).6.According to LVMI,hypertensives were divided into high,medium and low groups.Compared to low group,both of lying and standing BRS in high group were lower(lying: 6.16±2.72 vs 8.08±3.39;standing: 3.51±1.52 vs 4.56±1.64 ms/mmHg).7.In addition,it showed that BRS reduction is an independent factor for albuminuria and carotid atherosclerosis in hypertensive patients.Conclusion:1.Spontaneous BRS can reflect the state of cardiovascular autonomic nerve function,and has a good correlation with the heart rate variability index(SDNN).2.Patients with essential hypertension had significantly lower lying and standing BRS than those healthy ones.When combined with diabetes the degree of reduction was even more pronounced.3.Cardiac sympathetic nerve activity in hypertensives with high salt intake was higher than those with low salt intake,and there was a significant positive correlation between cardiac sympathetic nerve activity and salt intake.The BRS in the high-salt group was significantly lower than that in the low-salt group.4.Hypertensives with early target organ damage,such as albuminuria,carotid atherosclerosis,increased LVMI,had lower BRS;Lying BRS is an independent correlative factor for microalbuminuria and carotid atherosclerosis.