TREND AND PREDICTORS OF ARTERIAL COMPLIANCE IN A GROUP OF NON-HYPERTENSIVE AND UNTREATED HYPERTENSIVE SUBJECTS IN YAOUNDE.

Joshua Walinjom (joshwali@yahoo.com)
Internal Medicine, University of Yaounde 1
June, 2013
 

Abstract

Objective: Arterial compliance decreases with age and this decrease is accelerated by hypertension. Carotid-femoral pulse wave velocity (cfPWV) is the current “gold-standard” measure of arterial compliance and stands out as an important independent predictor of cardiovascular events. The European Society of Cardiology declared that, a cfPWV threshold value of >12 m/sec should be used to stratify cardiovascular risks in hypertensive patients. Measuring arterial compliance in the different stages of hypertension can therefore be used to stratify cardiovascular risk with respect to the severity of hypertension. The main objectives of this study were to determine the trend and predictors of arterial compliance in non-hypertensive and untreated hypertensive stage 1, 2 and 3 subjects.
Methods: A cross-sectional analytic study was designed. Our sample size involved a total of 88 participants 25 of whom were non-hypertensive while 22, 21 and 20 were untreated hypertensive stage 1, 2 and 3 patients respectively. The PulsePen® device was used to determine; carotid-femoral or aortic PWV and central augmentation index % (AIx). Left ventricular hypertrophy (LVH) was investigated using a 12 leads Cardiax® ECG machine. Other measurements obtained were blood pressure (BP), body mass index (BMI), fasting glycaemia, lipid profile and serum creatinine. Data were analyzed using the R-software and Microsoft Excel. Statistical analyses were performed by Mann-Whitney test, Pearson’s chi square test, Student’s t – test, Kruskal-Wallis test and Jonckheere’s trend test. Multivariate logistic regression analysis was used to identify the potential predictors of pulse wave velocity.
Results: Of the 88 participants studied, 51.1% were females and 48.9% were males. The mean age of the study population was 35.48 years and ranged from 20 to 60 years. The mean of hemodynamic parameters (cfPWV, carotid-radial.PWV, Central Systolic Blood Pressure (SBP), Central Diastolic Blood Pressure (DBP), Central Pulse Pressure (PP), Peripheral SBP, Peripheral DBP, Mean Arterial Pressure (MAP), Herat Rate (HR), and Central AIx ) showed a statistically significant increase in trend (p-value < 0.05) as we moved across the groups from non-hypertensive to severely hypertensive patients. The number of subjects who had a cfPWV>12m/s increased across the groups with the greatest number found amongst severely hypertensive patients. cfPWV was significantly correlated to Age, Central SBP, Central DBP, Central PP, Peripheral SBP, Peripheral DBP, MAP, HR, BMI and central AIx. (p-value< 0.05). cfPWV was significantly dependent on LVH (p-value <0.05). We found out that, hypertension stage, Age, BMI and HR were potential predictors of cfPWV.
Conclusion: Arterial compliance, an important independent predictor of cardiovascular events, is determined by cfPWV. In our study, hemodynamic parameters showed a statistically significant increase in trend across the groups from non-hypertensive to severely hypertensive patients. cfPWV showed a statistically significant correlation to Age, Central SBP, Central DBP, Central PP, Peripheral SBP, Peripheral DBP, MAP, HR, BMI, central AIx and LVH. Also, the values of cfPWV increased in trend as we moved across the groups, with most subjects having a PWV >12m/s being severely hypertensive patients. This clearly shows that arterial compliance decreases with increase severity of hypertension, indicating a higher risk of developing cardiovascular events in severely hypertensive subjects.
Keywords: Arterial Compliance, pulse wave velocity, Hypertension stage


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