Autoregulation of Cerebral Blood Flow is Preserved in Primary Intracerebral Hemorrhage

Abstract

Background and Purpose— Treatment of acute hypertension after intracerebral hemorrhage (ICH) is controversial. In the context of disrupted cerebral autoregulation, blood pressure (BP) reduction may cause decreased cerebral blood flow (CBF). We used serial computed tomography perfusion to test the hypothesis that CBF remains stable after BP reduction. Methods— Patients recruited within 72 hours of ICH were imaged with computed tomography perfusion before and after BP treatment. Change in perihematoma relative (r) CBF after BP treatment was the primary end point. Results— Twenty patients were imaged with computed tomography perfusion at a median (interquartile range) time from onset of 20.2 (25.7) hours and reimaged 2.1 (0.5) hours later, after BP reduction. Mean systolic BP in treated patients (n=16; 4 untreated as BP<target at baseline) decreased significantly between the first (168±21 mm Hg) and second (141±19 mm Hg; P <0.0001) computed tomography perfusion scans. The primary end point of rCBF was not affected by BP reduction (pretreatment=0.89±0.11; post-treatment=0.87±0.11 mL/100 g per minute; P =0.37). Linear regression showed no relationship between changes in systolic BP and perihematoma rCBF (β=0.001 [−0.002 to 0.003]; P =0.63). Conclusions— CBF remained stable after acute BP reduction, suggesting some preservation of cerebral autoregulation.

Impaired cerebral autoregulation: measurement and application to stroke

“…Perihaematoma tissue is moderately hypoperfused and therefore may be vulnerable to blood pressure reduction. However, in contrast, a CTP study in 20 patients within 72 hours of ICH indicated that CBF remained stable after acute blood pressure reduction, suggesting some preservation of CA which was assessed by linear regression analysis between systolic blood pressure and relative CBF measured by CTP 54. Using the TFA method, 26 patients with ICH were studied on days 1, 3 and 5 after ictus to evaluate the time course of dynamic CA in acute ICH and its relationship with clinical outcome 5.…”

Temporal Course of Dynamic Cerebral Autoregulation in Patients With Intracerebral Hemorrhage

“…Previous studies [3][4][5] applied the concept of static CA, which focuses on the baseline alteration of cerebral blood flow in ICH patients before and after the use of different strategies of blood pressure reduction to determine whether CA is preserved. With the advent of transcranial Doppler ultrasonography and techniques of noninvasive continuous blood pressure measurement, the high temporal resolution recordings of blood flow velocity and blood pressure allow for the assessment of dynamic cerebral autoregulation (dCA) from the responses of blood flow to instantaneous changes of blood pressure.…”

Reduced perfusion in normal‐appearing white matter in mild to moderate hypertension as revealed by 3D pseudocontinuous arterial spin labeling

“…Several methods can be used to detect changes in CBF in vivo; for instance, transcranial Doppler technique (TCD), 9 computed tomography (CT) perfusion imaging, 10 positron emission tomography (PET), 11 and magnetic resonance imaging (MRI) including dynamic susceptibility contrast (DSC), 12 and arterial spin labeling (ASL) perfusion imaging. More recently, 3D pseudocontinuous arterial spin labeling (pCASL) using fast spin-echo (FSE) spiral acquisition has been developed to allow higher signal-to-noise ratio (SNR) and better immunity to the arterial transit effect.…”

“…More recently, 3D pseudocontinuous arterial spin labeling (pCASL) using fast spin-echo (FSE) spiral acquisition has been developed to allow higher signal-to-noise ratio (SNR) and better immunity to the arterial transit effect. 13 The noninvasive nature of 3D pCASL makes it an appealing technique for follow-up examinations of cerebral perfusion in both clinical applications and research studies. However, the reported blood flow in WM was 1.6-4.6-fold lower compared to that in the gray matter (GM).…”