Cerebral Artery Blood Velocity Research Articles

The Need to Consider Pro-Active Treatment for Cerebral Artery Conditional Blood Velocity Determined By Transcranial Doppler Ultrasonography (TCD) in Sickle Cell Disease (SCD)

Introduction Cerebral artery peak systolic blood velocity (PSV) or timed average mean of the maximum blood velocity (TAMMV) determined by TCD in children of age 2-16 years with SCD is normal (NV) if TAMMV <170 cm/sec or PSV <200 cm/sec; abnormal (AV) if TAMMV > 200cm/s or PSV > 250 cm/sec; and conditional (CV) if TAMMV is 170-199cm/sec or PSV 200-249 cm/sec. Internal carotid (ICA) or middle cerebral (MCA) artery AV is associated with a stroke risk of 10% /year, CV a risk of 3-4% /year [Adams et al. Long-Term stroke risk in children with SCD screened with TCD. Ann Neurol 1997; 42: 699-704]. Blood transfusion or hydroxycarbamide is used to treat AV, but active treatment is currently not considered the standard of care for conditional velocity, although it could progress to abnormal values. ObjectiveTo evaluate the need for pro-active treatment of cerebral artery conditional blood velocity in children of age 2-16 years with SCD. Methods Following IRB approval and informed consent/assent, 308 children with SCD (126 girls and 182 boys, age 2-16 years) had TCD to determine PSV (n=193) or TAMMV (n=115) in the MCA, ICA and anterior cerebral arteries (ACA). This design was to make the research findings relevant to hospitals with TCD equipment that measure either PSV or TAMMV. Exclusion criteria were blood transfusion in the previous 4 months, therapy with hydroxycarbamide, omega-3 fatty acids or other agents that affect the severity of SCD, pregnancy, breast feeding, chronic disorders unrelated to SCD (such as diabetes mellitus) and stroke. Children with AV were started on a blood transfusion program. Those with conditional PSV were randomized in a 2:1 ratio to receive either standard care of SCD and active treatment with omega-3 fatty acids and potassium thiocyanate, or standard care only. After 3 months, measurement of PSV in the ICA, MCA and ACA was repeated. Study data were analysed with the Statistical Package for Social Sciences version 23 (IBM, USA). ResultsIn the TAMMV cohort of 115 children, 96 (84%) had NV, 7 (6%) AV, and 12 (10%) CV. Figure 1 shows the cumulative frequency of TAMMV in the MCA where most AV and CV occurred. In the PSV cohort of 193 children, 150 (77.7%) had NV, 7 (3.6%) AV, and 36 (18.7%) CV. There were no significant differences in gender or age distribution between the PSV and TAMMV cohorts. Altogether, cerebral artery blood velocity was normal in 246/308 children (80%), abnormal in 14 (4.5%) and conditional in 48 (15.5%). The PSV in 21 patients randomized to active treatment of conditional blood velocity or standard SCD care are shown in Table 1. After 3 months, PSV reduced to normal (<200cm/sec) in a significantly higher proportion (11/14 or 79%) of children on active treatment compared with 3/7 (43%) on standard care only, p = 0.04. Change in the right MCA median PSV showed a significant difference of 54cm/sec between children on active treatment who had a reduction from 201.5 cm/sec to 169.5 cm/s, and the standard care group with a rise from 184cm/s to 206 cm/sec (p = 0.018). One of 7 patients on standard care (14%) but none of 14 on active treatment (0%) had progression of PSV from conditional to abnormal. Reduction in conditional velocity following active treatment has been reported from other studies [Lagunju et al, Pediatr Blood Cancer 2015;62:1587-91; Estepp et al. Br J Haematol 2021;194:463-8]. Although not statistically significant, pre/post-treatment median steady state Hb level in actively treated patients showed an upward trend [6.8/7.3g/dl]; and the median platelet count a downward trend: 278/235 x10 9/l. The standard care group had opposite, but also not significant, trends: 7.45/7.0 g/dl, 224/261 x10 9/l. Discussion and Conclusion The 15.5% prevalence of conditional velocity translates to 15,500 /100,000 children born annually with SCD in our country, or 46,500 worldwide, of whom 1,860 (4%) may have stroke. If 14% of CV progress to AV, that is 6,510/year globally. If all are not treated, a reality in resource-limited places, any number up to 651 (10%) may develop stroke. The annual incidence, cumulative prevalence and progression rates of CV, and the significant difference in the proportion that revert to NV on active treatment compared to standard care only, suggest that there is need to consider CV for active treatment. This will prevent the cumulation of more than 1,860 children who develop stroke every year with its health, psychosocial and economic burden to the patients, their families and society.

Attenuated pulsatile transition to the cerebral vasculature during high-intensity interval exercise in young healthy men.

What is the central question of this study? High-intensity interval exercise (HIIE) is recommended for its favourable haemodynamic stimulation, but excessive haemodynamic fluctuations may stress the brain: is the cerebral vasculature protected against exaggerated systemic blood flow fluctuation during HIIE? What is the main finding and its importance? Time- and frequency-domain indices of aortic-cerebral pulsatile transition were lowered during HIIE. The findings suggest that the arterial system to the cerebral vasculature may attenuate pulsatile transition during HIIE as a defence mechanism against pulsatile fluctuation for the cerebral vasculature. High-intensity interval exercise (HIIE) is recommended because it provides favourable haemodynamic stimulation, but excessive haemodynamic fluctuations may be an adverse impact on the brain. We tested whether the cerebral vasculature is protected against systemic blood flow fluctuation during HIIE. Fourteen healthy men (age 24 ± 2 years) underwent four 4-min exercises at 80-90% of maximal workload (Wmax ) interspaced by 3-min active rest at 50-60% Wmax . Transcranial Doppler measured middle cerebral artery blood velocity (CBV). Systemic haemodynamics (Modelflow) and aortic pressure (AoP, general transfer function) were estimated from an invasively recorded brachial arterial pressure waveform. Using transfer function analysis, gain and phase between AoP and CBV (0.39-10.0Hz) were calculated. Stroke volume, aortic pulse pressure and pulsatile CBV increased during exercise (time effect: P<0.0001 for all), but a time-domain index of aortic-cerebral pulsatile transition (pulsatile CBV/pulsatile AoP) decreased throughout the exercise bouts (time effect: P<0.0001). Furthermore, transfer function gain reduced, and phase increased throughout the exercise bouts (time effect: P<0.0001 for both), suggesting the attenuation and delay of pulsatile transition. The cerebral vascular conductance index (mean CBV/mean arterial pressure; time effect: P=0.296), an inverse index of cerebral vascular tone, did not change even though systemic vascular conductance increased during exercise (time effect: P<0.0001). The arterial system to the cerebral vasculature may attenuate pulsatile transition during HIIE as a defence mechanism against pulsatile fluctuation for the cerebral vasculature.

Ultrasound flow phantom for transcranial Doppler: An assessment of angular mismatch effect on blood velocity measurement in comparison to optical particle image velocimetry

Detecting abnormal blood flow is possible through transcranial Doppler (TCD) ultrasound by measuring blood velocity in cerebral arteries. Velocity measurements are at the highest precision when the direction of blood flow coincides with the ultrasound beam. However, because TCD is typically performed blindly (i.e., without a B-mode), a 0° interrogation angle is usually assumed. This leads to a common issue of angular mismatch. This study quantitatively shows the angular mismatch effects on the measured velocities using a TCD ultrasound flow phantom compared with the velocities measured by optical particle image velocimetry (PIV) as control. Resulting errors with and without ultrasound machine angular correction were also considered. An ultrasound phantom developed by combining polyvinyl alcohol hydrogel (PVA-H), quartz glass as a scatterer, and a gypsum plate as a skull bone was utilized to approximate the middle cerebral artery TCD measurement from the temporal window. The PVA-H and quartz glass compositions were controlled to achieve transparency and enable PIV velocity measurement. Then, TCD velocity measurement was conducted on several interrogation and mismatch angles. Comparison results revealed that without an ultrasound machine angle correction, all measurements yielded underestimation with 73.9% at the highest in the 80° interrogation window at the 130 mL/min flow. On the other hand, with the correction, the errors in almost all angles were comparatively lower; however, at 80° at the 124 mL/min flow, a maximum overestimation rate of 113.7% was found, showing a larger error magnitude. Therefore, we find that angular mismatch, especially in larger angles, leads to inaccurate velocity measurements in TCD. Our results suggest that despite angle correction, velocity errors may still occur when the interrogation angle changes.

Cerebral artery conditional blood velocity in sickle cell disease: a multicentre study and evidence for active treatment

ObjectiveTo obtain multicentre data on the prevalence of normal, high or conditional (intermediate) blood velocity in the cerebral arteries among children with sickle cell disease (SCD) in Nigeria.DesignA prospective observational...

Association of laboratory markers and cerebral blood flow among sickle cell anemia children.

BackgroundStroke is one of the highest complications of sickle-cell anemia (SCA). The Transcranial Doppler (TCD) has been adopted worldwide as a gold standard method for detecting alterations in the blood velocity in cerebral arteries. In this study, we investigated the association between laboratory parameters and increased cerebral blood flow velocity in Brazilian SCA pediatric patients.MethodsThe study included 159 pediatric patients with SCA, submitted to TCD velocity screening, and the time-averaged maximum mean velocity (TAMMV) was determined in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and distal intracranial internal carotid artery (ICA). We compared cerebral blood flow in patients stratified by the following: TCD1—defined as normal, with TAMMV inferior to 170 cm/s; TCD2—conditional, with TAMMV above 170 cm/s, but less than 199 cm/s; TCD3—altered, with TAMMV greater than or equal to 200 cm/s.ResultsTAMMV was negatively correlated with age and weight (p < 0.05). Moreover, TAMMV was associated or correlated with reductions in HbF, RBC, hemoglobin, hematocrit, HDL, and haptoglobin and, increases in MCV, MCH, RDW, reticulocytes, WBC, lymphocytes, monocytes, eosinophils, total and indirect bilirubin, LDH, AST, ALT, glucose, ferritin, and AAT (p < 0.05).ConclusionThe current study highlights the importance of the investigation of hemolytic and inflammatory biomarkers for monitoring the clinical outcome of SCA pediatric patients, to avoid acute or chronic stroke. Moreover, glucose and HDL-C appear useful for predicting higher TAMMV.

Effect of Hyperinsulinemia on Cerebral Autoregulation and Myogenic Control of Cerebral Blood Flow in Healthy Young Adults

ObjectiveHyperinsulinemia has marked vasodilatory effects within the skeletal muscle vasculature in healthy young adults; however, the magnitude of insulin‐stimulated cerebrovascular vasodilation is less clear. Differences between circulations may be due to a greater importance of the cerebral circulation to maintain a constant level of blood flow (i.e., cerebral autoregulation) during hyperinsulinemia. We hypothesized cerebral autoregulation would increase during hyperinsulinemia. Autoregulatory mechanisms, such as myogenic control, play important roles in mediating cerebral vasomotor responses. Thus, we further sought to examine the contribution of the myogenic mechanism to the control of cerebral blood flow during hyperinsulinemia.MethodsMiddle cerebral artery blood velocity (MCAv) and femoral artery blood velocity (FAV) were measured with Doppler ultrasound and femoral artery blood flow (FBF) was calculated in 17 healthy adults (11M/6F, 28±2 yrs, 24±1 kg/m2) at baseline and following a hyperinsulinemic (40 mU/m2body surface area/min), euglycemic infusion. Finger plethysmography was used to assess mean blood pressure (MBP). Normalized transfer function gain between changes in MBP and MCAv were estimated in the 0.02‐0.07 Hz (very low frequency, VLF) and 0.07–0.20 Hz (low frequency, LF) ranges using the Welch method. Interactions between MBP and MCAv or FAV were determined using cross‐correlation analyses.ResultsIntravenous insulin infusion increased plasma insulin concentrations (6±1 to 50±3 μIU/mL, p&lt;0.01) with blood glucose maintained at baseline levels (p=0.33). There was a significant increase in FBF (121±15 to 151±19 mL/min, p=0.03) during hyperinsulinemia, with no change in MCAv (61±4 to 59±4 cm/s, p=0.28) or MBP (86±2 to 89±2 mmHg, p=0.10). There was no effect of hyperinsulinemia on normalized transfer function gain in the VLF (p=0.25) or LF ranges (p=0.46). Hyperinsulinemia had no effect on the association between MBP and MCAv (p=0.15) or FAV (p=0.82).ConclusionsHyperinsulinemia in healthy young adults elicits peripheral vasodilation, but no change in MCAv. Contrary to our hypothesis, the sensitivity of the cerebrovascular circulation to changes in MBP (i.e., cerebral autoregulation) is not altered during systemic hyperinsulinemia in healthy adults. Furthermore, the contribution of the myogenic mechanism to the control of blood flow in the peripheral and cerebral circulations is unaffected by hyperinsulinemia. Whether these results translate to disease states (e.g., diabetes) and the implications for cerebrovascular health warrant further exploration.

Measuring resting cerebral haemodynamics using MRI arterial spin labelling and transcranial Doppler ultrasound: Comparison in younger and older adults.

IntroductionResting cerebral blood flow (CBF) and perfusion measures have been used to determine brain health. Studies showing variation in resting CBF with age and fitness level using different imaging approaches have produced mixed findings. We assess the degree to which resting CBF measures through transcranial Doppler (TCD) and arterial spin labeling (ASL) MRI provide complementary information in older and younger, fit and unfit cohorts.MethodsThirty‐five healthy volunteers (20 younger: 24 ± 7y; 15 older: 66 ± 7y) completed two experimental sessions (TCD/MRI). Aging and fitness effects within and between imaging modalities were assessed.ResultsMiddle cerebral artery blood velocity (MCAv, TCD) was lower and transit time (MRI) slower in older compared with younger participants (p < .05). The younger group had higher gray matter cerebral perfusion (MRI) than the older group, albeit not significantly (p = .13). Surprisingly, fitness effects in the younger group (decrease/increase in MCAv/transit time with fitness, respectively) opposed the older group (increase/decrease in MCAv/transit time). Whole cohort transit times correlated with MCAv (r=−0.63; p < .05), whereas tissue perfusion did not correlate with TCD measures.ConclusionTCD and MRI modalities provide complementary resting CBF measures, with similar effects across the whole cohort and between subgroups (age/fitness) if metrics are comparable (e.g., velocity [TCD] versus transit time [MRI]).

The effect of steady-state CO2 on regional brain blood flow responses to increases in blood pressure via the cold pressor test.

The pressure-passive cerebrovasculature is affected by alterations in cerebral perfusion pressure (CPP) and arterial blood gases (e.g., pressure of arterial [Pa]CO2), where acute changes in either stimulus can influence cerebral blood flow (CBF). The effect of superimposed increases in CPP at different levels of steady-state PaCO2 on regional CBF regulation is unclear. In 17 healthy participants, we simultaneously recorded continuous heart rate (electrocardiogram), blood pressure (finometer), pressure of end-tidal CO2 (PETCO2; gas analyzer), and middle (MCA) and posterior (PCA) cerebral artery blood velocity (CBV; transcranial Doppler ultrasound). Three separate CPTs were administered by passive immersion of both feet into 0-1 °C of ice water for 3-min under three randomized and coached steady-state PETCO2 conditions: normocapnia (room air), hypocapnia (-10 Torr; hyperventilation) and hypercapnia (+9 Torr; 5% inspired CO2;). CBV responses were calculated as the absolute difference (∆) between baseline and mean MCAv and PCAv during the 3-min CPT. Both the ∆MCAv and ∆PCAv responses to the CPT were larger under hypercapnic conditions. The absolute ∆MCAv response was larger than the ∆PCAv during the CPT across all three CO2 trials. Cerebrovascular CO2 reactivity (CVR) was larger in the MCA than PCA in both CPT and baseline conditions, but there were no differences in CVR between CPT and baseline conditions. Our data indicate that (a) increases in CO2 increases the CBV responses to a CPT, (b) the anterior cerebrovasculature is more responsive to a CPT-induced increases in MAP, and (c) although unchanged during a CPT, CVR is larger in the anterior cerebral circulation.

The Impact of Caffeine on Dynamic Cerebral Autoregulation in Habitual Consumers

Caffeine is an adenosine receptor antagonist that is consumed daily by 90% of the United States population and can lead to adenosine receptor upregulation. In caffeine‐naïve individuals, drinking caffeine increases dynamic cerebral autoregulation as assessed by the rate of regulation (RoR) but the influence of caffeine in habitual users is unclear. We aimed to investigate whether dynamic cerebral autoregulation in middle and posterior cerebral arteries was altered by caffeine consumption in habituated consumers. Nine healthy subjects (age: 27 ± 6 yrs, Ht: 179 ± 14 cm, Wt: 76.1 ± 13.6 kg) completed three trials where they drank (6.25ml/kg body mass) either caffeinated coffee (CAF; 4mg caffeine/kg body mass), decaffeinated coffee (DECAF), or water (WATER). Before subjects drank anything (pre drink) we measured mean arterial pressure (MAP; mmHg), middle (MCAv; cm/s) and posterior (PCAv; cm/s) cerebral artery blood velocities at baseline and then during two successive thigh occlusion/release protocols to examine dynamic cerebral autoregulation (Rate of Regulation: RoR, 1/s). Subjects were then given one of the three drinks in a double‐blind, counterbalanced design. Thirty minutes later baseline measurements and the assessment of RoR were repeated (post drink). MAP decreased 14 ± 4 mmHg across all trials following thigh cuff deflation in the assessment of RoR pre drink. Pre drink RoR in the MCA was CAF: 0.19 ± 0.13, DECAF: 0.21 ± 0.14 and WATER: 0.21 ± 0.09 1/s. Pre drink RoR in the PCA was CAF: 0.24 ± 0.18, DECAF: 0.16 ± 0.15 and WATER: 0.23 ± 0.12 1/s. MAP increased from pre to post drink (CAF: 84 ± 7 to 98 ± 6 mmHg; DECAF: 88 ± 10 to 95 ± 6 mmHg and WATER: 89 ± 9 to 97 ± 5 mmHg; p = 0.002), but was not different between trials (p &gt; 0.05). MAP decreased 14 ± 3 mmHg across all trials following thigh cuff deflation in the assessment of RoR post drink. Post drink, MCA RoR demonstrated an interaction effect between trial and time (p = 0.047) and a main effect of time (p = 0.042). Post drink MCA RoR increased in the CAF trial relative to pre drink (0.40 ± 0.17 1/s; p = 0.008) but was unchanged in DECAF (0.23 ± 0.12 1/s) and WATER trials (0.23 ± 0.11 1/s) (both p &gt; 0.05 vs. pre drink). Post drink, PCA RoR was not different relative to pre drink (CAF: 0.35 ± 0.13, DECAF: 0.20 ± 0.11 and WATER: 0.21 ± 0.10 1/s) and did not demonstrate a main effect of time (p = 0.335), trial (p = 0.081) nor an interaction effect (p = 0.414). These findings suggest that caffeine consumption increases dynamic cerebral autoregulation in habituated consumers and supports the increased RoR found in the MCA following caffeine administration in caffeine naïve individuals.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Peripheral chemoreflex inhibition with low-dose dopamine: new insight into mechanisms of extreme apnea.

The purpose of this study was to determine the impact of peripheral chemoreflex inhibition with low-dose dopamine on maximal apnea time, and the related hemodynamic and cerebrovascular responses in elite apnea divers. In a randomized order, participants performed a maximal apnea while receiving either intravenous 2 μg·kg(-1)·min(-1) dopamine or volume-matched saline (placebo). The chemoreflex and hemodynamic response to dopamine was also assessed during hypoxia [arterial O2 tension, (PaO2 ) ∼35 mmHg] and mild hypercapnia [arterial CO2 tension (PaCO2 ) ∼46 mmHg] that mimicked the latter parts of apnea. Outcome measures included apnea duration, arterial blood gases (radial), heart rate (HR, ECG), mean arterial pressure (MAP, intra-arterial), middle (MCAv) and posterior (PCAv) cerebral artery blood velocity (transcranial ultrasound), internal carotid (ICA) and vertebral (VA) artery blood flow (ultrasound), and the chemoreflex responses. Although dopamine depressed the ventilatory response by 27 ± 41% (vs. placebo; P = 0.01), the maximal apnea duration was increased by only 5 ± 8% (P = 0.02). The PaCO2 and PaO2 at apnea breakpoint were similar (P > 0.05). When compared with placebo, dopamine increased HR and decreased MAP during both apnea and chemoreflex test (P all <0.05). At rest, dopamine compared with placebo dilated the ICA (3.0 ± 4.1%, P = 0.05) and VA (6.6 ± 5.0%, P < 0.01). During apnea and chemoreflex test, conductance of the cerebral vessels (ICA, VA, MCAv, PCAv) was increased with dopamine; however, flow (ICA and VA) was similar. At least in elite apnea divers, the small increase in apnea time and similar PaO2 at breakpoint (∼31 mmHg) suggest the apnea breakpoint is more related to PaO2 , rather than peripheral chemoreflex drive to breathe.

Prediction of neonatal acidosis by ductus venosus Doppler pattern in high risk pregnancies

Abstract Study objective Evaluate whether ductus venosus (DV) Doppler velocimetry might be a good diagnostic tool of neonatal acidosis than umbilical artery (UA) and middle cerebral artery (MCA) blood velocities. Design Prospective observational study. Setting High risk pregnancy unit of Ain Shams University Maternity Hospital. Patients Thirty high-risk pregnant patients in their third trimester. Method Recording of DV, UA and MCA blood velocity in complicated pregnancies referred to umbilical artery (UA) velocimetry as one aspect of fetal surveillance. Measurements and main results DV S/D ratio was not reliable to predict hypoxia (AUC 66%), PI was weak (73%), but RI was reliable to predict hypoxia (AUC 88%). On comparing the diagnostic ability of DV RI and MCA S/D, DV RI showed a diagnostic ability than MCA S/D, AUC 88% and 82% respectively. Conclusion Abnormal DV blood velocity is more frequently recorded in high-risk pregnancies than UA, MCA blood velocities. Ductus venosus resistance index (DV RI) appears to be a better predictor of perinatal outcome than MCA S/D.

Cerebrovascular consequences of obstructive sleep apnea.

Obstructive sleep apnea (OSA) is defined by interrupted breathing during sleep due to airway obstruction with an ongoing respiratory effort. In adults, OSA most commonly is caused by decreased muscle tone (required for patency) in the soft tissues of the upper airway.[1][1] Symptoms of OSA include

Association between intracranial, arterial pulse pressure amplitudes and cerebral autoregulation in head injury patients

Objective: To explore whether intracranial pulse pressure amplitudes relate to arterial pulse pressure amplitudes and whether correlations between time-related changes in intracranial and arterial pulse pressure amplitudes associate with indices of cerebral autoregulation.Methods: A total of 257 continuous and simultaneous intracranial pressure (ICP), arterial blood pressure (ABP) and middle cerebral artery (MCA) blood velocity recordings were obtained 1–14 days after ictus in 76 traumatic head injury patients and analysed retrospectively. Clinical outcome was assessed using the Glasgow outcome scale (GOS). Pulse pressure amplitudes of corresponding single ICP and ABP waves were correlated in consecutive 200 wave pairs. Mean ICP, mean ABP and mean ICP wave amplitudes, and mean and systolic MCA blood flow velocities, were computed in consecutive 6 second time windows. The indices of cerebral autoregulation PRx (moving correlation between mean ICP and mean ABP), and Mx and Sx (moving correlation between mean and systolic MCA blood velocity and cerebral perfusion pressure) were calculated over 4 minute periods and averaged over each recording.Results: Intracranial pulse pressure amplitudes were not related to arterial pulse pressure amplitudes (mean of Pearson's correlations coefficients: 0.04). Outcome was related to mean ICP, PRx and Sx (p ≤ 0.04, multiple regression analysis). Correlations between intracranial and arterial pulse pressure amplitudes were weakly related to PRx (Pearson's correlation coefficient: 0.16; p=0.01), but were not related to the indices of cerebral autoregulation Mx (Pearson's correlation coefficient: 0.07) and Sx (Pearson's correlation coefficient: 0.04).Conclusions: In this cohort of pressure recordings, we found no evidence of a correlation between intracranial and arterial blood pressure amplitudes. The correlation appeared not to be related to the state of cerebral autoregulation, although a weak correlation was found with pressure reactivity index PRx.

Improved orthostatic tolerance by leg crossing and muscle tensing: indisputable evidence for the arteriovenous pump existence

The following is the abstract of the article discussed in the subsequent letter: Tensing of lower body muscles without or with leg crossing (LBMT, LCMT), whole body tensing (WBT), squatting, and sitting with the head bent between the knees (“crash position,” HBK) are believed to abort vasovagal

Clinical observation on the treatment of pseudobulbar paralysis by combined scalp and body acupuncture

Objective: To investigate the efficacy of scalp acupuncture in combination with body acupuncture for treating pseudobulbar paralysis.Methods: Eighty patients were randomly divided into treatment and control group, 40 cases each. The control group was treated by the routine method of Western medicine and the treatment group by combined scalp and body acupuncture on the basis of the former. The curative effect was evaluated after treatment in both groups. The influence of the treatment on mean blood velocity(MBV) in anterior, middle and posterior cerebral arteries was observed by transcranial Doppler(TCD) in both groups.Results: The total efficacy rate was 97.5% in the treatment group and 12.5% in the control group. The recovery rate was 75% in the treatment group and 0% in the control group. There was a significant difference between the two groups(P<0.01). TCD showed that blood velocity in cerebral arteries was significantly increased and the unbalanced stasis of the right and left cerebral blood flow changed in the treatment group. A comparison of MBV between pretreatment and posttreatment showedP <0.01.Conclusion: Scalp acupuncture in combination with body acupuncture has a good effect on pseudobulbar paralysis.

The effect of I.V. L-NG Methylarginine Hydrochloride (L-NMMA: 546C88) on Basal and Acetazolamide (Diamox®) induced Changes of Blood Velocity in Cerebral Arteries and Regional Cerebral Blood flow in Man

The aim of this study was to estimate the effect of Nitric Oxide synthase (NOS)-inhibition (L-NMMA) on the diameter of the middle cerebral artery (MCA) and on regional cerebral blood flow (rCBF). Furthermore, to assess the effect of L-NMMA on acetazolamide induced increases in MCA blood velocity (Vmean) and rCBF. In an open crossover design 12 healthy subjects attended the laboratory twice. The first day 6 mg/kg L-LNMMA i.v. over 15 min preceded 1 g acetazolamide i.v. over 5 min. Eight days later only acetazolamide was given. V(mean) in MCA was determined with transcranial Doppler (TCD) and rCBF with Xe-133 inhalation SPECT at baseline, after L-NMMA and 25 and 55 min after acetazolamide infusion. After L-NMMA the decrease in rCBF(MCA) was 6.8% (+/- 7.4) (P < 0.019, n = 12), whereas V(mean) was not affected (P = 0.83, n = 8). The change in MCA diameter was estimated to - 1.3% (P = 0.44, n = 8). L-NMMA did not affect acetazolamide increases in Vmean (P = 0.67, n = 8) nor rCBF (P = 0.29, n = 12). The percentage increase of V(mean) was 1.5 times that of rCBF (n = 8). Our data suggest that the basal tone of human cerebral arterioles but not of conduit arteries is NO-dependent. The action of acetazolamide in man is not NO-dependent.

Cerebral autoregulation in orthostatic intolerance.

Many of the primary symptoms of orthostatic intolerance (fatigue, diminished concentration) as well as some of the premonitory symptoms of neurally mediated syncope (NMS) are thought to be due to cerebral hypoperfusion. Transcranial Doppler measurements of middle cerebral artery blood velocity (CBV) is at present the only technique for assessing rapid changes in cerebral blood flow, and hence for evaluating dynamic cerebral autoregulation. However, controversies exist regarding data interpretation. At syncope, during the collapse of blood pressure (BP), diastolic CBV diminishes, whereas systolic CBV is maintained. Some consider this increase in CBV pulsatility to be indicative of a paradoxical increase in cerebrovascular resistance (CVR) prior to syncope. Others note that mean CBV decreases much less than does mean BP, implying that cerebral autoregulatory mechanisms are intact and functioning at syncope. Similarly, there is no evidence of impaired dynamic cerebral autoregulation, as measured by standard linear transfer-function analysis, in patients with NMS. Some patients with exaggerated postural tachycardia (POTS) have been found to have an excessive decrease in CBV during head-up tilt. Controversy exists as to whether this decrease results from an excessive sympathetic outflow to the cerebral vasculature or from hyperventilation. However, many other equally symptomatic patients with a similar hemodynamic profile of exaggerated tachycardia during head-up tilt have normal CBV changes during this maneuver and have normal dynamic cerebral autoregulation as determined by transfer-function analysis. Whether these discrepancies reflect different pathologies in patients with POTS is currently unknown.

Simultaneous bilateral assessment of middle cerebral artery (MCA) blood velocity (BV) during auditory tasks

Simultaneous bilateral assessment of middle cerebral artery (MCA) blood velocity (BV) during auditory tasks

Haemodynamic aspects of clinical cerebral angiography concurrent two vessel monitoring using transcranial Doppler ultrasound

To overcome the technical limitations which have precluded noninvasive Doppler ultrasound in investigation of rapid cerebral haemodynamic responses in two cerebrovascular beds at the same time, we have modified a commercial 2 MHz pulsed Doppler instrument with online spectrum analysis. Two probes are activated intermittently, recording eight averaged Doppler-shifted spectra from each probe sequentially. Concurrent recordings of blood velocity in both middle cerebral arteries were performed during 25 selective iohexol carotid angiography runs in 13 patients with near normal cerebral vasculature. The technique permitted the differentiation between the specific responses confined to the recipient vascular bed, and the general responses occurring in remote brain areas as well. The specific response to iohexol was biphasic; a significant decrease in blood velocity occurred less than 4 s after the bolus entry, probably due to the high viscocity of iohexol. Between 4 and 12 s. blood velocity was significantly increased, reflecting the cerebrovascular response to hypertonic solutions. The blood velocity on the opposite side increased from less than 4 s through 45 s after iohexol. This concurs with studies using electromagnetic flowmetry, and suggests that these general responses are elicited by anxiety, discomfort and pain. Thus, no general responses were seen during angiography under general anaesthesia. Eight patients investigated during catheter flushing with normal saline showed a biphasic specific response reciprocal to that due to iohexol. A significant blood velocity peak occurred less than 4 s after the bolus entry, followed by a decrease between 4 and 60 s. The saline injections produced no pain and evoked no significant general response.

Side-to-side differences and day-to-day variations of transcranial Doppler parameters in normal subjects.

We investigated 35 normal adults to assess variations in cerebral artery blood velocities, hemispheric blood velocity ratios, and pulsatility indices, both with regard to changes between the sides and between days. We found no significant variations between sides or days. Changes from one day to the next exceeding 20% in blood velocity in the middle cerebral artery (VMCA), the anterior cerebral artery (VACA), the distal extracranial internal carotid artery (VICA), and in the hemispheric VMCA/VICA, VACA/VICA, or VACA/VMCA ratios, may be considered significant at the 95% level.