Correlation of Pre-Hypertension with Carotid Artery Damage in Middle-Aged and Older Adults

Ultra sonographic indices of the carotid artery in healthy adult population of southwest, Nigeria: a cross-sectional study

Introduction

atherosclerosis develops insidiously, offering time and opportunities for early detection. Screening for subclinical atherosclerosis via structural wall changes and flow velocities among apparently healthy adults using carotid ultrasonography may help its early detection, offer timely intervention and reduce morbidity and mortality.

Methods

a cross-sectional study of 100 participants with a mean age of 56.1 ± 6.9 years, were enrolled from a community population. Both carotid arteries were examined for plaques, carotid intima-media thickness (CIMT), and flow velocities - peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistive index (RI) using 4-12MHz linear array transducer. Visceral obesity, serum lipids, and blood glucose were also evaluated and correlated with ultrasound findings.

Results

the mean CIMT was 0.07 ± 0.02cm and 15% of the participants had increased CIMT. Statistically significance but weak correlations were observed between CIMT and FBG (r = 0.199, p = 0.047), EDV (r =0.204, p= 0.041), PI (r = -0.287, p = 0.004) and RI (r = -0.268, p =0.007). Statistically significance with modest correlations were observed between EDV and PSV (r = 0.48, p = 0.000), PI (r = -0.635, p = 0.000) and RI (r = -0.637, p = 0.000). The PI and RI showed strong correlation with statistical significance (r= 0.972, p = 0.000).

Conclusion

statistical significance in the flow velocities, derived flow indices and increased CIMT may be an early indication of subclinical atherosclerosis. Therefore, ultrasonography may facilitate its early detection and possible prevention of complications.

Subject-Specific Pressure Normalization of Local Pulse Wave Velocity: Separating Intrinsic From Acute Load-Dependent Stiffening in Hypertensive Patients

Pulse wave velocity (PWV) is a powerful predictor of cardiovascular events. However, its intrinsic blood pressure (BP)-dependency complicates distinguishing between acute and chronic effects of increased BP on arterial stiffness. Based on the assumption that arteries exhibit a nearly exponential pressure-area (P-A) relationship, this study proposes a method to assess intersubject differences in local PWV independently from BP. The method was then used to analyze differences in local carotid PWV (cPWV) between hypertensive and healthy normotensive people before and after BP-normalization. Pressure (P) and diameter (D) waveforms were simultaneously acquired via tonometer at the left and ultrasound scanning at right common carotid artery (CCA), respectively, in 22 patients with Grade 1 or 2 hypertension and 22 age- and sex-matched controls. cPWV was determined using the D²P-loop method. Then, the exponential modeling of the P-area (A = πD²/4) relationships allowed defining a mathematical formulation to compute subject-specific changes in cPWV associated with BP changes, thus enabling the normalization of cPWV against intersubject differences in BP at the time of measurement. Carotid systolic BP (SBP) and diastolic BP (DBP) were, on average, 17.7 (p < 0.001) and 8.9 mmHg (p < 0.01) higher in hypertensives than controls, respectively. cPWV was 5.56 ± 0.86 m/s in controls and 6.24 ± 1.22 m/s in hypertensives. BP alone accounted for 68% of the cPWV difference between the two groups: 5.80 ± 0.84 vs. 6.03 ± 1.07 m/s after BP-normalization (p = 0.47). The mechanistic normalization of cPWV was in agreement with that estimated by analysis of covariance (ANCOVA). In conclusion, the proposed method, which could be easily implemented in the clinical setting, allows to assess the intersubject differences in PWV independently of BP. Our results suggested that mild hypertension in middle-aged subjects without target organ damage does not significantly alter the stiffness of the CCA wall independently of acute differences in BP. The results warrant further clinical investigations to establish the potential clinical utility of the method.