Predicting the Target Organ Damage in Primary Hypertension Patients by Evaluating Heart Rate and Circadian Rhythm of Blood Pressure

The incidence of essential hypertension is increasing in this century and mostlyaccompanying with the (TOD) target organ damage (heart, brain, kidney and bloodvessels, etc).So early detection and intervention of the TOD is important. There are a lotof methods to detect TOD evaluation, and the recommended tools for detection are thepulse wave velocity (PWV), left ventricular mass index (LVMI), urine albumincreatinine ratio (ACR) etc. PWV is widely recognized as an evaluation of vascularfunction, especially the carotid-to-femoral pulse wave velocity (cfPWV). LVMI notonly regarded as the early detection of the left ventricular hypertrophy, also for theprediction of morbidity and mortality in the cardiac diseases. Moreover, ACR can detectthe early renal damage in the hypertension. One more point to be noted is that circadianblood pressure abnormalities and increase in heart rate can find in both normotensiveand hypertensive patients. ABPM is one of the instrument for detecting the circadianrhythm and24h heart rate. Many studies showed that the existence of relationshipbetween circadian rhythm abnormalities and increase in the heart rate. Disappearing ofnight dippers and increasing in heart rate with the increase of the salt loading in the saltsensitive hypertensive patients. Thus, circadian rhythm abnormalities and raise in theheart rate can be hopefully recommended for the evaluation of salt sensitivehypertension.Objective: We are going to estimate the TOD by measuring the PWV, LVMI andACR in this study, discussing about the relationship of the TOD in hypertensive patientwith the results of circadian rhythm and heart rate, and analyze the cardiovascular riskfactors for the TOD. Methods: The174patients, admitted to the First Affiliated Hospital of DalianMedical University during October2010to March2012, were enrolled in this study.The174patients, who were18-75years old patients, diagnosed hypertension accordingto the2005Chinese Hypertension Guideline. ACR was attained by urinalysis,application of automatic arteriosclerosis detector for PWV, cardiac color Dopplerultrasound examination and calculation of LVMI, using MGY-ABP1type BP recordingmachine for ABPM. The174patients were divided into3groups according to the24-hour heart rate and blood pressure circadian rhythm. We used the SPSS13.0software package and Microsoft Office Excel2007for statistical processing andanalyzing the data, using one way ANOVA to compare between these three groups.Results:1. The comparison of basic data between the three groups did not showthe statistical significance (P>0.05);[age, body mass index (BMI), smoking, Diabetesmellitus, Triglyceride (TG), Low-density Lipoprotein cholesterol (LDL-C), Totalcholesterol (TC), High-density Lipoprotein (HDL), Uric acid (UA), Creatinine (Cre)],but the clinical significance present on analyzing the sex difference(P=0.022).2. After correction of the gender of the patients, PWV does not have statisticalsignificant in these three groups (P>0.05). ACR differences among the three groups isstatistically significant (P=0.004), in which high risk group higher than the low riskgroup, intermediate risk group higher than low risk group, the differences arestatistically significant(P=0.001,0.016). LVMI differences among the three groups isstatistically significant (P=0.000), in which high risk group higher than intermediaterisk group than low risk group, intermediate risk group higher than low risk group, thedifferences are statistically significant(P=0.026,0.000,0.004).3. When comparing the three groups of male patients, ACR and LVMI are higherin high risk group than in low risk group, and there is the statistical different (P=0.005,0.005). The PWV does not have statistical significant in these three groups (P>0.05). Infemale patients, LVMI is lesser in low risk group than high risk, has statisticalsignificant (P=0.001), but ACR and PWV have no difference (P>0.05).4. PWV, LVMI, ACR and other indicators were analyzed by the simplecorrelation analysis. The results showed that PWV was positively correlated with theage and diabetes mellitus. ACR and UA were correlated significantly with24h HR,DBP, mean arterial blood pressure, day time DBP, nocturnal HR, SBP, and MAP.LVMI was also apparently related with the24h HR, SBP, DBP, MAP, day time BP,SBP, DBP, MAP, nocturnal HR, SBP, DBP, MAP.5. Multiple linear regression analysis showed that PWV is independently correlated with the age, smoking and DM, in which smoking has the strongestcorrelation. Moreover, HR, UA, DBP and ACR are also independently correlated withPWV, whereas uric acid showed the highest correlation. Finally, HR, nocturnal SBP hasthe independent correlation with LVMI, in which HR is the most correlation.Conclusion:1.After correction of the gender of the patients, circadian rhythmabnormalities and increase in heart rate in essential hypertensive patients will notsignificant effect on atherosclerosis, and will progress faster in renal damage and leftventricular hypertrophy.2. Circadian rhythm abnormalities and increase in heart rate in essentialhypertensive male patients will progress faster in renal damage and left ventricularhypertrophy. Female patients with essential hypertension will promote the risk of leftventricular hypertrophy in circadian rhythm abnormalities and rising in heart rate.3. Increasing in age, DM are acting as a contributing factor for the development ofatherosclerosis, increasing in HR and DBP are going to stimulate the declining in renalfunction, increasing in heart rate and elevated nocturnal SBP will promote the leftventricular hypertrophy therefore.