Cerebral Blood Flow Changes With Diuretic Therapy in Elderly Subjects with Systolic Hypertension

Abstract

It has been feared that lowering the blood pressure (BP) of elderly patients with systolic hypertension (SH) may compromise cerebral perfusion. To test this hypothesis, BP, cerebral blood flow (CBF), plasma renin activity (PRA), blood counts, urinary and serum electrolytes and other blood chemistries were measured in fifteen elderly patients (ages 61-76 years) with SH (systolic BP greater than 170 and diastolic BP less than 100 mmHg). Gray matter flow (Fg) was calculated from clearance curves of inhaled 133-Xenon. All subjects were studied while untreated, as well as during long-term treatment (average 15 weeks) with hydrochlorothiazide. BP fell during treatment from 186/90 to 160/86 while average Fg and cerebrovascular resistance (CVR) were not significantly changed. There was some suggestion, however, that in patients who became normotensive the CVR decreased (p less than 0.05) while in those who did not Fg fell (p less than 0.05). Cerebrovascular response to 5% CO2 inhalation was impaired during both the treated and untreated states. Individual changes in Fg and CVR did not correlate with changes in BP or with changes in PRA, electrolytes or other chemistries. In general, cautious, gradual reduction of BP with a thiazide diuretic in SH of the elderly seems not to impair cerebral perfusion, but individual differences exist and further studies are needed to characterize them.

Intolerance to initial orthostasis relates to systolic BP changes in elders

“…Furthermore, SBP has been positively correlated with white matter CBF in the posterior and anterior brain regions of Alzheimer's patients [25]. On the other hand, pharmacological studies with older hypertensive subjects have shown that SBP reductions do not necessarily mirror concomitant reductions in CBF [22,27]. Perhaps the two groups in our study had differences in cerebral autoregulation, but we cannot test this hypothesis.…”

Cerebral White Matter and Retinal Arterial Health in Hypertension and Type 2 Diabetes Mellitus

“…Another limitation is that we do not have information regarding smoking in our participants, and details regarding hypertension and diabetes medications or antiplatelet use were only available for 35/62 of the participants. Antihypertensive medications, such as diuretics, have effects on cerebral autoregulation [33], but only two of our subjects reported diuretic use, so we do not think that this significantly contributed to our findings. Future studies should utilize autoregulation or cerebral blood flow assessments to ascertain their possible effects on WM abnormalities.…”

Effect of Long-Term Antihypertensive Treatment on the Cerebral Blood Flow in Patients with Brain Infarction

“…In long-standing hyper tension, the lower limit shifts to a higher level than that in the normotensives, resulting in a narrowing of the autoregulatory range. A réadaptation of cerebral autoregula tion is also expected in some cases after long-term and effective antihypertensive treatment [13], and the CBF in such cases did not significantly change or even increased despite a reduction in the systemic blood pressure by anti hypertensive treatment [12,14,15]. Thus, a careful and gradual lowering of blood pressure is necessary, and it is of primary importance to maintain a sufficient CBF.…”

“…change in mean arterial blood pressure, infarct size and duration of antihypertensive treatment. The change in CBF was counted when it was 15% or more, since the reproducibility of the CBF determination with the IJ3Xe inhalation technique carries an error of up to 10 -15% [ 12], Differences were considered signifi cant when a probability value was under 0.05.…”