Cerebral Hemodynamics In Patients Research Articles

Dynamic Autoregulation is Impaired in Circulatory Shock.

Circulatory shock is a life-threatening disorder that is associated with high mortality, with a state of systemic and tissue hypoperfusion that can lead to organ failure, including the brain, where altered mental state is often observed. We hypothesized that cerebral autoregulation (CA) is impaired in patients with circulatory shock. Adult patients with circulatory shock and healthy controls were included. Cerebral blood flow velocity (CBFV, transcranial Doppler ultrasound) and arterial blood pressure (BP, Finometer or intra-arterial line) were continuously recorded during 5 min in both groups. Autoregulation Index (ARI) was estimated from the CBFV response to a step change in BP, derived by transfer function analysis; ARI ≤ 4 was considered impaired CA. The relationship between organ dysfunction, assessed with the Sequential Organ Failure Assessment (SOFA) score and the ARI, was assessed with linear regression. Twenty-five shock patients and 28 age-matched healthy volunteers were studied. The mean ± SD SOFA score was 10.8 ± 4.3. Shock patients compared with control subjects had lower ARI values (4.0 ± 2.1 vs. 5.9 ± 1.5, P = 0.001). Impaired CA was more common in shock patients (44.4% vs. 7.1%, P = 0.003). There was a significant inverse relationship between the ARI and the SOFA score (R = -0.63, P = 0.0008). These results suggest that circulatory shock is often associated with impaired CA and that the severity of CA alterations is correlated with the degree of multiple organ failure, reinforcing the need to monitor cerebral hemodynamics in patients with circulatory shock.

Cerebral hemodynamics in patients with extracranial internal carotid artery disease

Cerebral hemodynamics in patients with extracranial internal carotid artery disease

Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial

ObjectiveIt is hypothesised that cervical manipulation may increase the risk of cerebrovascular accidents. We aimed to determine whether cervical spine manipulation is associated with changes in vertebral artery and cerebrovascular...

Comparison between intracranial collaterals and cerebral hemodynamics in patients with extracranial carotid stenosis versus combined extra- and intracranial stenosis using transcranial duplex

BackgroundIn acute ischemic stroke, collateral circulation plays an important role in maintaining blood flow to the tissue that is at risk of progressing into ischemia, and in increasing the successful recanalization rate without hemorrhagic transformation.ObjectivesTo compare between collaterals in patients with extracranial carotid stenosis alone and in patients having both extracranial and intracranial carotid stenosis and therefore the difference in prognosis between them.Materials and methodsA total of 30 patients of acute ischemic stroke were enrolled. The extracranial part of the carotid artery was assessed with color-coded duplex. Transcranial color-coded duplex was done to assess cerebral hemodynamics and collaterals to differentiate between extracranial significant carotid stenosis alone versus combined extra- and intracranial significant carotid stenosis.ResultsOut of 15 patients with significant extracranial stenosis, 3 of them obtained reversed flow in the ophthalmic artery and 3 patients of them showed change of flow in the anterior cerebral artery(ACA), whereas the other 15 patients of combined stenosis did not show any reversed blood flow in the same arteries which considered nonsignificant. The residual deficit of patients with extracranial stenosis alone was better when compared to that of the other group.ConclusionOur study concluded that transcranial duplex provides useful information about cerebral reserve and status of collaterals which show nonsignificant difference between two studied groups regarding intracranial collaterals. Furthermore, patients with combined extra- and intracranial stenosis were found to have more deficit and worse prognosis than patients with internal carotid stenosis only.

Cerebral hemodynamics in patients with ankylosing spondylitis.

The aim of this study was to assess the cerebral blood flow velocity as a marker by using transcranial Doppler (TCD) ultrasonography in patients with ankylosing spondylitis (AS). A total of 30 AS patients aged 20 to 50 were enrolled in the AS group (male/female: 4/26, mean age: 34.7 ± 5.9) consecutively. The control group (non-AS group; male/female: 4/26, mean age: 32.3 ± 4.7) consisted of 30 age- and sex-matched, randomly selected patients without AS who had other diagnoses such as fibromyalgia and did not have risk factors for atherosclerosis. Bilateral middle cerebral artery (MCA) peak-systolic, end-diastolic, and mean blood flow velocities, Gosling's pulsatility index values, and Pourcelot's resistance index values were recorded with TCD by a neurosonologist blinded to the AS and control groups. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels and cerebral blood flow velocities of bilateral MCA were significantly higher in the AS group than in the control group. This study highlights that the increased cerebral blood flow is indirectly associated with atherosclerosis regarding persistent inflammation in patients with AS.

Cerebral Hemodynamics in Patients with Rheumatoid Arthritis

A total of 22 patients aged 20 to 40-years-old with RA were enrolled in the RA group consecutively. Control group (non-RA group) consisted of 22 age and sex-matched, randomly selected patients without RA who had other diagnosis such as fibromyalgia and did not have risk factors for atherosclerosis (AS).

Changes in Cerebral Hemodynamics in Patients With Cirrhosis After Liver Transplantation.

Improvement in cognitive function after orthotopic liver transplantation (LT) has been demonstrated in the acute setting immediately after LT and in acute liver failure. However, the longterm changes in cerebral hemodynamics after LT remain unexplored. Therefore, we aimed to evaluate the longterm changes in cerebral hemodynamics of patients with cirrhosis after LT. In this prospective cohort study, we performed transcranial Doppler ultrasonography (TCD) measuring the pulsatility index (PI), resistance index (RI), and breath-holding index (BHI) to evaluate cerebrovascular structural integrity and reactivity, respectively, in both middle cerebral arteries before and after LT. Neuropsychometric tests and West-Haven criteria were used for hepatic encephalopathy (HE) characterization. Interleukin 6 and tumor necrosis factor α plasma levels were measured. Descriptive statistics and Wilcoxon's test were used. There were 27 patients who were included. Median follow-up after LT was 6 months, mean age before LT was 46.3 ± 10.3 years, the main etiology was hepatitis C virus (59%), and most of the patients were Child-Pugh B (15/27). Model for End-Stage Liver Disease (MELD) score was 16 ± 7.5, MELD-Na was 19.3 ± 7.1, Psychometric Hepatic Encephalopathy Score was -3.48 ± 3.66, and critical flicker fusion (CFF) was 40.28 ± 5.70 Hz. Before LT, 17/27 patients had HE and 11/27 ascites. A decrease of 20.8% and 13.5% in PI and RI was observed after LT (P < 0.001, both), together with an increase in BHI (32.4%, P = 0.122). These changes in cerebral hemodynamics paralleled those in systemic inflammation. Clinical improvement in cognition was observed in all patients with overt HE after LT. In conclusion, these results show a significant improvement in cerebral hemodynamics after LT, obtained through TCD, indicating less arterial cerebral vasoconstriction together with a decrease in systemic inflammation. Changes in cerebral vasoconstriction can be the basis for the improvement in cognitive function after LT in the long term.

Long-term changes in cerebrovascular reactivity following EC-IC bypass for intracranial steno-occlusive disease

The purpose of this retrospective observational study is to investigate the long-term changes in cerebrovascular reactivity (CVR) as a measure of cerebral hemodynamics in patients with intracranial steno-occlusive disease (IC-SOD) after they have undergone an Extracranial–intracranial (EC-IC) bypass. Twenty-six patients suffering from IC-SOD were selected from our CVR database. Nineteen patients underwent unilateral and 7 underwent bilateral revascularization. CVR measurements were done using BOLD-MRI and precisely controlled CO2 and expressed as ΔBOLD (%)/Δ PETCO2 (mmHg). Trends in CVR over time were compared in both vascularized and non-vascularized hemispheres. Repeated measures analysis of variance with Greenhouse-Geisser correction was used to determine CVR changes within the grey matter MCA for longitudinal assessments. Overall, re-vascularized hemisphere showed a significant increase in CVR at the first follow-up, followed by a slight decrease at the second follow-up that significantly increased compared to the pre-bypass. However, the changes in the postoperative CVR were quite variable across the patients. Similar variability was seen in subsequent follow-ups, with a slight overall decline in the long term CVR as compared with first post-operative CVR. Our study demonstrates that EC-IC bypass has a beneficial long-term effect on cerebral hemodynamics and this effect varies between patients probably due to the variability in the underlying vascular pattern receiving the bypass. Hence, in the postoperative follow-up of patients routine functional imaging to monitor cerebral hemodynamics may be useful as the risk of stroke and cognitive decline remain present with impaired CVR.

Evaluation of the Effects of Acupuncture on Cerebral Hemodynamics in Patients Suffering from Cerebrovascular Pathology with Duplex Ultrasound Doppler Imaging

Evaluation of the Effects of Acupuncture on Cerebral Hemodynamics in Patients Suffering from Cerebrovascular Pathology with Duplex Ultrasound Doppler Imaging

The clinical application of transcranial doppler ultrasonography in severe traumatic brain injury post decompressive craniectomy

Objective To explore the clinical application of transcranial doppler ultrasonography (TCD) in severe traumatic brain injury (sTBI)post decompressive craniectomy. Methods A retrospective study was conducted on 58 patients with sTBI who were admitted to Neurosurgical Intensive Care Unit of Tangdu Hospital, the Fourth Military Medical University From January 2015 to October 2016. All patients underwent hematoma evacuation, decompressive craniectomy and placement of intracerebral pressure (ICP) probe. The parameters of cerebral blood flow including mean velocity (Vmean), end of diastolic (Vedv) and pulsatility index (PI) in sTBI patients were measured by TCD post operation to assess the cerebral blood supply. Results The trend of Vmean and Vedv manifested U-shaped mode during the next 7 days, reaching the lowest levels [(72.5±22.6) cm/s and (43.6±19.8) cm/s, respectively] on day 3. There was significant difference in the value of Vmean between day 3 and day 1, 2, 5, 6, 7 (all P<0.05). There was significant difference in the value of Vedv between day 3 and day 1, 2, 6, 7 (all P<0.05). The trend of pulsatility index (PI) and intracranial pressure (ICP) showed parabolic shape during the next 7 days, reaching the highest level [(1.5±0.7) and (17.2±4.5)mmHg, respectively] on day 4. Significant difference was observed in ICP between day 4 and day 1, 2, 3, 6, 7 (P<0.05). The incidence of cerebral hyperemia showed the trend of declining during the next 7 days. There was significant difference in cerebral hyperemia between day 1 and day 5, 6, 7 (all P<0.05). The incidence of cerebral ischemia was up to 36.2% (12/58) on day 4, and it was significantly higher than that on day 1 (P<0.05). The incidence of cerebral vasospasm showed the rising trend and reached the highest level (15.5%) on day 6, which had significant difference compared with the incidences on day 1, 2 and 3 (all P<0.05). Conclusion TCD, as a noninvasive, portable, easy-to-use monitoring tool, could help effectively evaluate postoperative changes of cerebral hemodynamics in patients with sTBI. Key words: Craniocerebral trauma; Ultrasonography, doppler, transcranial; Decompressive craniectomy

Cerebral hemodynamics with intra-aortic balloon pump: business as usual?

Objective: Intra-aortic balloon pump (IABP) is commonly used as mechanical support after cardiac surgery or cardiac shock. Although its benefits for cardiac function have been well documented, its effects on cerebral circulation are still controversial. We hypothesized that transfer function analysis (TFA) and continuous estimates of dynamic cerebral autoregulation (CA) provide consistent results in the assessment of cerebral autoregulation in patients with IABP.Approach: Continuous recordings of blood pressure (BP, intra-arterial line), end-tidal CO2, heart rate and cerebral blood flow velocity (CBFV, transcranial Doppler) were obtained (i) 5 min with IABP ratio 1:3, (ii) 5 min, starting 1 min with the IABP-ON, and continuing for another 4 min without pump assistance (IABP-OFF). Autoregulation index (ARI) was estimated from the CBFV response to a step change in BP derived by TFA and as a function of time using an autoregressive moving-average model during removal of the device (ARIt). Critical closing pressure and resistance area-product were also obtained.Main results: ARI with IABP-ON (4.3 ± 1.2) were not different from corresponding values at IABP-OFF (4.7 ± 1.4, p = 0.42). Removal of the balloon had no effect on ARIt, CBFV, BP, cerebral critical closing pressure or resistance area-product.Significance: IABP does not disturb cerebral hemodynamics. TFA and continuous estimates of dynamic CA can be used to assess cerebral hemodynamics in patients with IABP. These findings have important implications for the design of studies of critically ill patients requiring the use of different invasive support devices.

Reduced Cerebral Blood Flow in Mild Cognitive Impairment Assessed Using Phase-Contrast MRI.

There is increasing evidence of a vascular contribution to Alzheimer's disease (AD). In some cases, prior work suggests that chronic brain hypoperfusion could play a prime pathogenic role contributing to the accumulation of amyloid-β,while other studies favor the hypothesis that vascular dysfunction and amyloid pathology are independent, although synergistic, mechanisms contributing to cognitive impairment. Vascular dysfunction can be evaluated by assessing cerebral blood flow impairment. Phase contrast velocity mapping by MRI offers a non-invasive means of quantifying the total inflow of blood to the brain. This quantitative parameter could be a sensitive indicator of vascular disease at early stages of AD. In this work, phase contrast MRI was used to evaluate cerebral hemodynamics in patients with subjective memory complaints, amnestic mild cognitive impairment, and mild to moderate AD, and compare them with control subjects. Results showed that blood flow and velocity were decreased in the patients with cognitive dysfunction and the decrease correlated with the degree of cognitive impairment as assessed by means of neuropsychological tests. Total cerebral blood flow measurements were clearly reduced in AD patients, but more importantly appeared to be sensitive enough to distinguish between healthy subjects and those with mild cognitive impairment. A quantitative measurement of total brain blood flow could potentially predict vascular dysfunction and compromised brain perfusion in early stages of AD.

Abstract TP115: Cerebral Hemodynamic Changes in Military Personnel With Long-term Effects of Concussions

Service members (SMs) suffer from repeated exposure to concussions or mild TBI, which can disrupt cerebral blood flow. This effect is seen in the acute phase of TBI, but the development of vascular wall abnormalities, which can lead to luminal narrowing and abnormally elevated cerebral blood flow velocities (CBFV), has not been studied in the post concussive phase. The purpose of this study was to evaluate the transcranial Doppler (TCD) determined incidence of abnormal cerebral hemodynamics in patients with long-term effects of mTBI. Material and Methods: TCD recordings of mean CBFV in cm/sec and Pulsatility Indices (PI) were recorded from 431 SMs (9 females; ages 24-54, mean age 39.2 ± 6.4 years) who were admitted to the National Intrepid Center of Excellence 4-week Interdisciplinary Outpatient Program. TCD data were analyzed to determine whether SMs exhibited abnormal CBFV s in the middle cerebral artery, internal carotid artery (ICA), and basilar artery. All subjects consented to protocol #362504 prior to any data collection or analysis. Two standard deviation from the mean CBFV in any direction labeled as an abnormal and PI was assumed normal with values between 0.7 and 0.9 Patients with one or more vessels with abnormal CBFV’s and PI’s were labeled as abnormal. Results: Average time since last TBI was 5.1 ± 3.4 years. We observed abnormal CBFV values in 33% of SMs. 149 (35%) and 48 (11%) demonstrated abnormally high CBFV and PIs in one or more vessels, respectively. Abnormal CBFV was observed most frequently in the ICA (48%). Majority of studied patients had patchy pattern of abnormal data presented in one or few vessels. The presence of abnormal cerebral hemodynamics was inversely related to the time since the last mTBI exposure: the likelihood of abnormal CBFV values deceased with increasing time since last head injury was sustained but was still present. Conclusions: Our data reveal that a large proportion of SMs have elevated CBFVs following mTBI exposure in many years after last mTBI. We believe that head injuries due to combat and training blast and blunt force trauma exposure cause early atherosclerotic or fibrotic changes in the large vessel walls of the Circle of Willis, which results in vascular lumen narrowing and increased CBFV’s.

The influence of Cytoflavin therapy on the cerebral hemodynamics in patients with various stages of hypertensive disease

To study an influence of cytoflavin therapy on the cerebral hemodynamics in patients with various stages of hypertensive disease (HD). One hundred and forty patients with HD, I-III stages, were randomized into 2 groups: patients of group 1 received complex treatment (antihypertensive therapy and cytoflavin), patients of group 2 were treated with antihypertensive therapy. The control group consisted of 30 healthy people. The changes in cerebral hemodynamics using the algorithm of the complex ultrasound study of cerebral vascular system were assessed. Disturbances of hemodynamics at all structural/functional levels of cerebral vascular system were found in all HD stages. There were a decrease in the blood flow through the common carotid, inner carotid, spinal and middle cerebral arteries, reactivity of veins of Rosenthal, blood flow through veins of Rosenthal and inner jugular veins and an increase of blood flow through spinal veins. The hemodynamic study showed that in group 1 there was the increase of blood flow through common carotid, inner carotid, middle cerebral arteries in stage I and through spinal arteries in stage I-II of HD; improvement of the reactivity of veins of Rosenthal, restoration of blood flow parameters through the veins of Rosenthal and inner jugular veins to control values, the decrease in blood flow velocity through the spinal veins in all HD stages. HD is accompanied by the damage of all structural/functional levels of cerebral vascular system. The use of cytoflavin in the complex therapy of HD exerts a positive influence on the cerebral hemodynamics reducing the severity of arterial insufficiency in the initial stages of disease, improving microcirculation and venous hemodynamics in all HD stages.

An effect of cerebral hemodynamics in patients with cerebrovascular disorders on the in-hospital transportation

In-hospital transportation of 76 patients with cerebrovascular disorders, including those in the first postoperative day, was performed. Two cerebral hemodynamic measurements were carried out five minutes before and immediately after transportation using transcranial Doppler sonography. Significant changes in cerebral blood flow in the operated patients were shown. No significant effect on the rate of cerebral blood flow was identified in patients with ischemic lesions.

Changes in cerebral perfusion in patients undergoing revascularization of carotid artery stenosis

Ischemic stroke is caused by atherosclerotic lesions in extra- and intracranial arteries in about 25% of cases. Revascularization surgery has been long and widely used for secondary prevention of ischemic stroke in patients with atherosclerotic lesions of the carotid arteries. However, currently the changes in cerebral perfusion in patients with atherosclerotic lesions of brachiocephalic arteries, who underwent surgical revascularization, are still not fully understood. This article highlights the issues of changes of cerebral hemodynamics in patients undergoing surgery on the carotid arteries.

Cerebral Hemodynamics in Patients with Hemolytic Uremic Syndrome Assessed by Susceptibility Weighted Imaging and Four-Dimensional Non-Contrast MR Angiography.

Background and PurposeConventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause.Materials and MethodsBaseline 1.5T MRI scans of 36 patients (female, 26; male, 10; mean age, 38.2±19.3 years) were evaluated. Venous contrast was rated on standard SWI minimum intensity projections. A prototype four-dimensional (time resolved) magnetic resonance angiography (4D MRA) assessed cerebral hemodynamics by global time-to-peak (TTP), as a surrogate marker for CBF. Clinical parameters studied were hemoglobin, hematocrit, creatinine, urea levels, blood pressure, heart rate, and end-tidal CO2.ResultsSWI venous contrast was abnormally low in 33 of 36 patients. TTP ranged from 3.7 to 10.2 frames (mean, 7.9 ± 1.4). Hemoglobin at the time of MRI (n = 35) was decreased in all patients (range, 5.0 to 12.6 g/dL; mean, 8.2 ± 1.4); hematocrit (n = 33) was abnormally low in all but a single patient (range, 14.3 to 37.2%; mean, 23.7 ± 4.2). Creatinine was abnormally high in 30 of 36 patients (83%) (range, 0.8 to 9.7; mean, 3.7 ± 2.2). SWI venous contrast correlated significantly with hemoglobin (r = 0.52, P = 0.0015), hematocrit (r = 0.65, P < 0.001), and TTP (r = 0.35, P = 0.036). No correlation of SWI with blood pressure, heart rate, end-tidal CO2, creatinine, and urea level was observed. Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS. SWI contrast of patients with pathological conventional MRI findings was significantly lower compared to patients with normal MRI (mean SWI score, 1.41 and 2.05, respectively; P = 0.04). In patients with abnormal conventional MRI, mean TTP (7.45), mean hemoglobin (7.65), and mean hematocrit (22.0) were lower compared to patients with normal conventional MRI scans (mean TTP = 8.28, mean hemoglobin = 8.63, mean hematocrit = 25.23).ConclusionIn contrast to conventional MRI, almost all patients showed pathological changes in cerebral hemodynamics assessed by SWI and 4D MRA. Loss of venous contrast on SWI is most likely the result of an increase in CBF and may be related to the acute onset of anemia. Future studies will be needed to assess a possible therapeutic effect of blood transfusions in patients with HUS and neurological symptoms.

Assessment of the severity of cognitive disorders based on cerebral hemodynamics in patients with stable angina

Cerebrovascular disease is a leading cause of death and disability in the world's population. The structure of these diseases occupies about 90% of chronic cerebral ischemia (CCI). Concomitant cardiac dysfunction disorder increases cerebral blood flow, leading to disruption of compensatory possibilities cerebrovascular system and the development of acute cerebrovascular events. It examined 21 patients aged (average age – 62.2 ± 7.9 years) with CCI and stable angina (SA) FC II and III. By age and sex of the two groups were equivalent. For patients with combined cerebral and cardiac pathology is a characteristic change in systemic hemodynamics mainly hypokinetic type. The data neuropsychological tests indicate more pronounced cognitive deficits in patients with CCI against the background SA FC III, shown a decrease in memory, attention, perception and orientation than in patients on background SA II FC.

Change in Cerebrovascular Resistance as Diagnostic Index of Cerebral Hemodynamics in Patients with Severe Combined Traumatic Brain Injury

Change in Cerebrovascular Resistance as Diagnostic Index of Cerebral Hemodynamics in Patients with Severe Combined Traumatic Brain Injury

Evaluation of Hemodynamic Cerebral Disordersin Patients Subjected to the Third Molar Extraction.Evaluation of the Effectiveness of OsteopathicRehabilitation after Tooth Extraction

Extraction of the third molars from the upper jaw can cause somatic dysfunctions and changes in cerebral hemodynamics in patients. Rehabilitation measures aimed to correct somatic dysfunctions and restore cerebral hemodynamics are necessary for these patients.