scholarly journals Middle cerebral artery pressure changes following Pipeline flow diversion

2018 ◽  
Vol 24 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Denise Brunozzi ◽  
Sophia F Shakur ◽  
Fady T Charbel ◽  
Ali Alaraj
Keyword(s):  
Blood Pressure ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Cerebral Aneurysms ◽  
Systemic Blood Pressure ◽  
Mean Blood Pressure ◽  
Systemic Blood ◽  
Arterial Blood ◽  
Before And After ◽  
Pressure Changes

Objective Pipeline embolization devices (PED) are commonly used for endovascular treatment of cerebral aneurysms but changes in intracranial hemodynamics after PED deployment are poorly understood. Here, we assess middle cerebral artery (MCA) and systemic blood pressure before and after PED treatment. Methods Records of patients with cerebral aneurysms proximal to the internal carotid artery terminus treated with PED at our institution between 2015 and 2017 were retrospectively reviewed. Patients were included if ipsilateral MCA pressure measurements were available. Ipsilateral MCA pressure was transduced via the microcatheter before and after PED deployment. Systemic arterial blood pressure was also simultaneously recorded. MCA, systemic blood pressure, and ratios of MCA to systemic blood pressure values were compared before and after treatment among the study cohort using the two-sample paired Student t test. Results Fourteen patients were included. Mean age was 54 years. Among the entire cohort, the ratio of MCA to systemic systolic and mean blood pressure were significantly higher after treatment (respectively 0.76 vs. 0.69, p = 0.01, and 0.94 vs. 0.89, p = 0.03), and the ratio of MCA to systemic diastolic pressures showed an increasing trend (1.08 vs. 1.03, p = 0.09). The percentage of ratio increase was independent of aneurysm size ( r = –0.24, p = 0.42 for systolic ratio; r = –0.09, p = 0.74 for diastolic ratio; r = –0.09; p = 0.76 for mean ratio, respectively). Conclusions Following PED deployment, the ratio of ipsilateral MCA to systemic systolic and mean blood pressure increased. These pressure changes should be further evaluated in a larger sample size.

Complexity of middle cerebral artery blood flow velocity: effects of tilt and autonomic failure

1997 ◽  
Vol 273 (5) ◽  
pp. H2209-H2216 ◽  
Author(s):  
A. P. Blaber ◽  
R. L. Bondar ◽  
F. Stein ◽  
P. T. Dunphy ◽  
P. Moradshahi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Autonomic Failure ◽  
Systemic Blood Pressure ◽  
Arterial Blood ◽  
Different Response

We examined spectral fractal characteristics of middle cerebral artery (MCA) mean blood flow velocity (MFV) and mean arterial blood pressure adjusted to the level of the brain (MAPbrain) during graded tilt (5 min supine, −10°, 10°, 30°, 60°, −10°, supine) in eight autonomic failure patients and age- and sex-matched controls. From supine to 60°, patients had a larger drop in MAPbrain (62 ± 4.7 vs. 23 ± 4.5 mmHg, P < 0.001; means ± SE) and MFV (16.4 ± 3.8 vs. 7.0 ± 2.5 cm/s, P < 0.001) than in controls. From supine to 60°, there was a trend toward a decrease in the slope of the fractal component (β) of MFV (MFV-β) in both the patients and the controls, but only the patients had a significant decrease in MFV-β (supine: patient = 2.21 ± 0.18, control = 1.99 ± 0.60; 60°: patient = 1.46 ± 0.24, control = 1.62 ± 0.19). The β value of MAPbrain(MAPbrain-β; 2.19 ± 0.05) was not significantly different between patients and controls and did not change with tilt. High and low degrees of regulatory complexity are indicated by values of β close to 1.0 and 2.0, respectively. The increase in fractal complexity of cerebral MFV in the patients with tilt suggests an increase in the degree of autoregulation in the patients. This may be related to the drop in MAPbrain. The different response of MFV-β compared with that of MAPbrain-β also indicates that MFV-β is related to the regulation of cerebral vascular resistance and not systemic blood pressure.

PS 02-65 ASSOCIATION BETWEEN POSTPRANDIAL AND SLEEPING SYSTEMIC BLOOD PRESSURE CHANGES IN THE NON-DIABETIC ELDERLY

2016 ◽  
Vol 34 (Supplement 1) ◽  
pp. e121
Author(s):  
Fernando Garcia ◽  
Beatriz Fidale ◽  
Sebastião Ferreira-Filho
Keyword(s):  
Blood Pressure ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Pressure Changes

Effects of systemic arterial blood pressure on the contractile force of a human hand muscle

2000 ◽  
Vol 88 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
Julie R. Wright ◽  
D. I. McCloskey ◽  
Richard C. Fitzpatrick
Keyword(s):  
Blood Pressure ◽  
Muscular Activity ◽  
Systemic Blood Pressure ◽  
Muscle Performance ◽  
Knee Extensors ◽  
Human Hand ◽  
Physiological Changes ◽  
Force Output ◽  
Systemic Blood ◽  
Arterial Blood

The effect of physiological changes in systemic blood pressure on the force output of working abductor pollicis (AP) muscle was studied in six normal subjects. Supramaximal tetanic stimulation at the ulnar nerve produced repeated isometric contractions at 1-s intervals. Force output declined gradually with time. During the train of contractions, subjects voluntarily contracted the knee extensors for 1 min; this raised systemic blood pressure by 29%. Force output from AP rose in parallel with blood pressure so that 18% of the contraction force lost through fatigue was recovered for each 10% increase in blood pressure. When blood pressure in the hand was kept constant despite the increased systemic pressure, force output did not rise. The results show that muscle performance is strongly affected by physiological changes in central blood pressure and suggest that sensory input concerning the adequacy of muscle performance exerts a feedback control over the increase in systemic blood pressure during muscular activity.

Method for measuring brain tissue pressure

1975 ◽  
Vol 43 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Robert M. Clark ◽  
Norman F. Capra ◽  
James H. Halsey
Keyword(s):  
Blood Pressure ◽  
Brain Tissue ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Tissue Pressure ◽  
Content Type ◽  
Pressure Changes ◽  
Local Brain

✓ The authors report a method for measuring total local brain tissue pressure (BTP) using a miniature catheter transducer stereotaxically introduced into the white matter of the cat's cerebrum. Quantitative rapid phasic pressure changes were satisfactorily demonstrated. Due to some drift of baseline of the transducers and inability to perform in vivo calibration, reliable long-term quantitative pressure measurements sometimes could not be studied. The BTP from each cerebral hemisphere and the cisternal pressure (CP) were monitored during alterations of pCO2 and systemic blood pressure, and distilled H2O injection prior to and after right middle cerebral artery (MCA) ligation. The catheter transducers functioned well on chronic implantation for up to 6 weeks. Compared to the chronically implanted catheters, acutely implanted catheters responded identically except for drift. The response of intracranial pressure and CP to MCA occlusion, alterations in pCO2, and systemic blood pressure were similar. No BTP gradients appeared in response to MCA ligation, hypercapnia, hypertension, or progressive swelling of the resulting infarction.

The effect of nimodipine on intracranial pressure

1987 ◽  
Vol 67 (3) ◽  
pp. 387-393 ◽  
Author(s):  
Mark N. Hadley ◽  
Robert F. Spetzler ◽  
Mary S. Fifield ◽  
William D. Bichard ◽  
John A. Hodak
Keyword(s):  
Blood Pressure ◽  
Intracranial Pressure ◽  
Systemic Blood Pressure ◽  
Artery Occlusion ◽  
Content Type ◽  
Arterial Blood ◽  
Increased Risk ◽  
Before And After ◽  
The Right ◽  
Cerebral Artery Occlusion

✓ Nimodipine was administered by intravenous infusion to six male baboons before, during, and after 6 hours of middle cerebral artery occlusion. Intracranial pressure (ICP) and systemic blood pressure were monitored continuously. An epidural balloon was inflated at regular intervals at three levels of arterial CO2 tension (25, 35, and 50 mm Hg) before and after the administration of nimodipine, and volume-pressure curves were generated. In every case, curves generated after intravenous nimodipine infusion were lower and shifted more to the right than the same set of curves generated before nimodipine administration, regardless of the baseline ICP. The reduction in ICP following nimodipine infusion was not due to a reduction in mean arterial blood pressure and was statistically significant at all three levels of pCO2 (p < 0.01). These results suggest that, in the presence of elevated ICP due to cerebral infarction, there is no increased risk of exacerbating intracranial hypertension with the addition of nimodipine.

Ouabain prevents loss of autoregulation in rat pial arterioles caused by reoxygenation after a brief hypoxic episode

1989 ◽  
Vol 67 (5) ◽  
pp. 423-427 ◽  
Author(s):  
J. Kettler ◽  
B. Y. Ong ◽  
D. Bose
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Protective Effects ◽  
Cranial Window ◽  
Arterial Blood ◽  
Hypoxic Episode ◽  
Electrogenic Sodium Pump ◽  
Before And After ◽  
Pressure Changes ◽  
Arteriolar Diameter

Pial arteriolar diameter changes inversely with changes in systemic arterial blood pressure. Such changes are consistent with autoregulatory functions. These responses are reduced by a brief period of hypoxia followed by reoxygenation. By using an open cranial window preparation we assessed the changes in pial arteriolar diameters during blood pressure changes in rats induced by hemorrhage and reinfusion of blood, before and after a brief period of hypoxia. The slopes of the changes in pial arteriolar diameter as a function of mean arterial blood pressure were −0.47 ± 0.26 μm/mmHg (mean ± SD; 1 mmHg = 133.3 Pa) before hypoxia and −0.11 ± 0.23 μm/mmHg after hypoxia in the untreated rats. In ouabain-treated rats, corresponding slopes were −0.42 ± 0.24 and −0.46 ± 0.22 μm/mmHg. The observed protective effects of ouabain might be a blockade of the Na–K pump in the sarcolemma of the vascular smooth muscle.Key words: vascular smooth muscle, electrogenic sodium pump, metabolic inhibition.

Impaired cerebrovascular autoregulation and reduced CO2 reactivity after long duration spaceflight

2012 ◽  
Vol 302 (12) ◽  
pp. H2592-H2598 ◽  
Author(s):  
K. A. Zuj ◽  
Ph. Arbeille ◽  
J. K. Shoemaker ◽  
A. P. Blaber ◽  
D. K. Greaves ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Middle Cerebral Artery ◽  
Arterial Blood Pressure ◽  
Cerebral Artery ◽  
Resistance Index ◽  
Arma Model ◽  
Functional Changes ◽  
Cerebrovascular Autoregulation ◽  
Arterial Blood ◽  
Long Duration

Long duration habitation on the International Space Station (ISS) is associated with chronic elevations in arterial blood pressure in the brain compared with normal upright posture on Earth and elevated inspired CO2. Although results from short-duration spaceflights suggested possibly improved cerebrovascular autoregulation, animal models provided evidence of structural and functional changes in cerebral vessels that might negatively impact autoregulation with longer periods in microgravity. Seven astronauts (1 woman) spent 147 ± 49 days on ISS. Preflight testing (30–60 days before launch) was compared with postflight testing on landing day ( n = 4) or the morning 1 ( n = 2) or 2 days ( n = 1) after return to Earth. Arterial blood pressure at the level of the middle cerebral artery (BPMCA) and expired CO2 were monitored along with transcranial Doppler ultrasound assessment of middle cerebral artery (MCA) blood flow velocity (CBFV). Cerebrovascular resistance index was calculated as (CVRi = BPMCA/CBFV). Cerebrovascular autoregulation and CO2 reactivity were assessed in a supine position from an autoregressive moving average (ARMA) model of data obtained during a test where two breaths of 10% CO2 were given four times during a 5-min period. CBFV and Doppler pulsatility index were reduced during −20 mmHg lower body negative pressure, with no differences pre- to postflight. The postflight indicator of dynamic autoregulation from the ARMA model revealed reduced gain for the CVRi response to BPMCA ( P = 0.017). The postflight responses to CO2 were reduced for CBFV ( P = 0.056) and CVRi ( P = 0.047). These results indicate that long duration missions on the ISS impaired dynamic cerebrovascular autoregulation and reduced cerebrovascular CO2 reactivity.

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