The Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial

Abstract

Background and Purpose— Acute blood pressure (BP) reduction aimed at attenuation of intracerebral hemorrhage (ICH) expansion might also compromise cerebral blood flow (CBF). We tested the hypothesis that CBF in acute ICH patients is unaffected by BP reduction. Methods— Patients with spontaneous ICH <24 hours after onset and systolic BP > 150 mm Hg were randomly assigned to an intravenous antihypertensive treatment protocol targeting a systolic BP of <150 mm Hg (n=39) or <180 mm Hg (n=36). Patients underwent computed tomography perfusion imaging 2 hours postrandomization. The primary end point was perihematoma relative (relative CBF). Results— Treatment groups were balanced with respect to baseline systolic BP: 182±20 mm Hg (<150 mm Hg target group) versus 184±25 mm Hg (<180 mm Hg target group; P =0.60), and for hematoma volume: 25.6±30.8 versus 26.9±25.2 mL ( P =0.66). Mean systolic BP 2 hours after randomization was significantly lower in the <150 mm Hg target group (140±19 vs 162±12 mm Hg; P <0.001). Perihematoma CBF (38.7±11.9 mL/100 g per minute) was lower than in contralateral homologous regions (44.1±11.1 mL/100 g per minute; P <0.001) in all patients. The primary end point of perihematoma relative CBF in the <150 mm Hg target group (0.86±0.12) was not significantly lower than that in the <180 mm Hg group (0.89±0.09; P =0.19; absolute difference, 0.03; 95% confidence interval −0.018 to 0.078). There was no relationship between the magnitude of BP change and perihematoma relative CBF in the <150 mm Hg ( R =0.00005; 95% confidence interval, −0.001 to 0.001) or <180 mm Hg target groups ( R =0.000; 95% confidence interval, −0.001 to 0.001). Conclusions— Rapid BP lowering after a moderate volume of ICH does not reduce perihematoma CBF. These physiological data indicate that acute BP reduction does not precipitate cerebral ischemia in ICH patients. Clinical Trial Registration Information— URL: http://clinicaltrials.gov . Unique Identifier: NCT00963976.

Extravascular Blood Augments Myogenic Constriction of Cerebral Arterioles: Implications for Hemorrhage‐Induced Vasospasm

“…We found similar myogenic responsive patterns in both in vivo and in vitro conditions that were clinically reminiscent of, first, adjusting high systemic blood pressure in patients after hemorrhagic stroke 14, 30. Interestingly, a recent clinical trial indicated that an acute reduction of systemic blood pressure did not significantly improve CBF to surrounding brain areas after hemorrhagic shock 31. The outcomes correspond to our findings showing that the enhanced myogenic constriction in response to exposure of arterioles to hemolyzed blood was present in a relatively lower pressure range (corresponding to 40–120 mm Hg systemic blood pressure), implying that lowering systemic blood pressure may not be sufficient to overcome enhanced myogenic constriction after hemorrhage.…”

Cerebral Perfusion Pressure is Maintained in Acute Intracerebral Hemorrhage: A CT Perfusion Study

“…15,17,31 In the present study, we found no relationship between BP treatment target or actual BP and perihematoma CPP. The maintenance of CPP despite marked reductions in BP in many of our patients suggests some preservation of autoregulation in patients with acute ICH.…”

“…16 In the Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial (ICH ADAPT), we demonstrated that acute BP reduction is not associated with a significant fall in CBF. 17 It has been demonstrated, however, that CPP is more sensitive than CBF or CBV to changes in blood pressure. 18 The relationship between CPP and BP reduction in patients with intracerebral hemorrhage is unknown.…”

“…17 Two patients were excluded from this analysis due to inadequate quality of raw CTP data required to complete CPP and CVR calculations. This study, therefore, included 73 patients (54 men), with a median age of 70 years (interquartile range, 60 -80 years).…”

Blood Pressure Reduction Does Not Reduce Perihematoma Oxygenation: A CT Perfusion Study

“…Direct measurement of the uptake rate of oxygen with 15 O-labeled water PET scan remains the gold standard for assessment of metabolic rate, and a more rigorous validation study of the flow heterogeneity technique in stroke patients remains outstanding. In addition, the maps generated in our study indicate that CBF and metabolism vary with tissue type.…”