1-5COMPARISON OF CEREBRAL BLOOD FLOW IN POSTERIOR CIRCULATION BETWEEN HYPERTENSIVE AND NORMOTENSIVE INDIVIDUALS

Abstract

Background and Purpose: Hypertension is known to be associated with cerebrovascular remodelling, raised cerebrovascular resistance and reduced resting cerebral blood flow (CBF) relative to the healthy normotensive individual. This study aimed to compare the CBF in posterior circulation between hypertensive and normotensive individuals. Methods: We collected data of transcranial doppler (TCD) examination from Neurosonology Division in Adam Malik General Hospital from January 2014 until December 2019. We included data of the right vertebral artery (RVA), left vertebral artery (LVA) and basilar artery (BA). The parameters included were mean flow velocity (MFV) and peak systolic velocity (PSV) to measure CBF and pulsatility index to assess the vascular resistance. We excluded patients with a history of stroke and patients with signs of stenosis from TCD examination. Results: There were 330 subjects included in this study, consisted of 160 hypertensive patients and 170 normotensive subjects. The mean age was 62.4 ± 8.1 years old. Compared to normotensive subjects, hypertensive patients had significantly lower MFV in RVA [29.71 ± 7.97 vs32.74 ± 9.07, p = 0.001] and in LVA [29.71 ± 9.68 vs 32.61 ± 9.06, p = 0.005]; lower PSV in RVA [50.57 ± 13.9 vs 54.11 ± 14.5, p = 0.024] and in LVA [48.3 ± 15.30 vs 52.6 ± 15.01, p = 0.011. There was no significant difference of MFV and PSV in BA between hypertensive and normotensive subjects [33.2 ± 1.06 vs 34.6 ± 1.06, p = 0.23 and 56.11 ± 17.5 vs 56.3 ± 17.5, p = 0.91, respectively]. The pulsatility index was higher in hypertensive patients compared to normotensive subjects in RVA [1.08 ± 0.24 vs 1.01 ± 30, p = 0.014] and in LVA [1.06 ± 0.28 vs 0.99 ± 0.33, p = 0.052] and in BA [1.14 ± 0.24 vs 1.03 ± 0.27, p = 0.001] although these were still within normal range. Conclusion: Hypertensive patients exhibited lower blood flow in posterior cerebral circulation compared to healthy normotensive subjects.