Low Blood Flow Research Articles

Dynamics of cerebral blood volume during and after middle cerebral artery occlusion in rats – Comparison between ultrafast ultrasound and dynamic susceptibility contrast-enhanced MRI measurements

Tomographic perfusion imaging techniques are integral to translational stroke research paradigms that advance our understanding of the disease. Functional ultrasound (fUS) is an emerging technique that informs on cerebral blood volume (CBV) through ultrasensitive Doppler and flow velocity (CBFv) through ultrafast localization microscopy. It is not known how experimental results compare with a classical CBV-probing technique such as dynamic susceptibility contrast-enhanced perfusion MRI (DSC-MRI). To that end, we assessed hemodynamics based on uUS (n = 6) or DSC-MRI (n = 7) before, during and up to three hours after 90-minute filament-induced middle cerebral artery occlusion (MCAO) in rats. Recanalization was followed by a brief hyperperfusion response, after which CBV and CBFv temporarily normalized but progressively declined after one hour in the lesion territory. DSC-MRI data corroborated the incomplete restoration of CBV after recanalization, which may have been caused by the free-breathing anesthetic regimen. During occlusion, MCAO-induced hypoperfusion was more discrepant between either technique, likely attributable to artefactual signal mechanisms related to slow flow, and processing algorithms employed for either technique. In vivo uUS- and DSC-MRI-derived measures of CBV enable serial whole-brain assessment of post-stroke hemodynamics, but readouts from both techniques need to be interpreted cautiously in situations of very low blood flow.

Low-load blood flow restriction strength training in patients with COPD: a randomised single-blind pilot study

ObjectiveThe objective of this study is to compare the effectiveness of lower limb low-load blood flow restriction training (LL-BFRT) with high-load strength training (HL-ST) as part of an outpatient pulmonary...

MEDICINAL BIOMAGNETISM FOR PAIN RELIEF IN VASCULAR ALTERATIONS - APPLICATION OF STATIC MAGNETIC FIELDS THROUGH THE PROTOCOL FOR BLOOD FLOW IN LOWER LIMBS

Introduction: Chronic Venous Insufficiency (CVI) is a set of clinical manifestations resulting from the chronic dysfunction of the peripheral venous system that affects the lower limbs. There is a growing search for complementary therapies, such as Medicinal Biomagnetism (MB), which acts in a non-invasive, painless, low-cost and with rare contraindications, aiming to improve quality of life. MB uses Static Magnetic Fields (SMF) to restore bioenergetic balance and promote health, including CVI. Objective: The aim of this study is to evaluate the effect of SMF application, through the MB Lower Limb Blood Flow Protocol (LLBFP), on pain resulting from vascular alterations of the lower limbs. Methodology: This is a cross-sectional clinical experimental study in three female participants with vascular alterations in the lower limbs who underwent the LLBFP Protocol. Pain, edema and quality of life complaints were assessed using the Venous Insufficiency Epidemiological and Economic Study (VEINES), Visual Analogue Scale (VAS), and perimeter measurements questionnaires, before and after the application of the LLBFP. Results: After treatment with the LLBFP Protocol, there was a trend towards the analgesic effect and reduction of edema, as well as improvement in the aspects related to the symptoms of heavy, restless, tired legs, and tingling, burning and itching, promoting improvement in quality of life. Conclusion: This study demonstrated that the application of the MB LLBFP Protocol has the potential to reduce the subjective perception of pain and edema in lower limbs with vascular alterations. The magnets used in the LLBFP may promote an anti-inflammatory response, contributing to the improvement of quality of life.

The Prevalence and Impact of Vertebral Artery Hypoplasia on Cerebral Hemodynamics

AbstractBackgroundVertebral artery hypoplasia (VAH) is an anatomical variation that may be associated with lower cerebral blood flow. We demonstrated the prevalence of VAH to be approximately 26% in a pilot study of healthy adults (n = 39). The purpose of this study was to expand on these findings by determining the prevalence of VAH and its impact on cerebral hemodynamics in a larger sample size of middle‐aged and older adults.MethodA total of 550 participants (66 ± 9 years; 346 females) underwent 4D flow MRI scans to evaluate the internal carotid arteries (ICA), vertebral arteries, and basilar artery. VAH+ (positive for VAH) was determined from the 4D flow MRI scans using both diameter (<2.5 mm) and flow (<47 mL/min).ResultWe identified 152 participants as VAH+ (prevalence of 28%). The prevalence of VAH+ was similar between females (n = 95; 27%) and males (n = 57; 28%). VAH predominantly occurred in the right vertebral artery (n = 102; 67%). As expected within VAH+ participants, the hypoplastic vertebral artery diameter was smaller (2.0±0.2 mm vs. 2.8±0.5 mm; p<0.001), blood flow was lower (29±10 ml/min vs. 100±44 ml/min; p<0.001), and pulsatility index was higher (1.8±0.6 a.u. vs. 1.3±0.3 a.u.; p<0.001) compared to the contralateral artery. There were no differences in ICA diameter (p = 0.875), blood flow (p = 0.553) or pulsatility index (p = 0.984) between VAH+ and no VAH. When evaluating the basilar artery, the diameter was smaller (2.7±0.4 mm vs. 2.8±0.4 mm; p = 0.037) with lower blood flow (105±35 ml/min vs. 116±37 ml/min; p<0.001) in VAH+ compared with no VAH. Males with VAH+ had higher basilar artery pulsatility index compared with males with no VAH (1.4±0.4 a.u. vs. 1.2±0.3 a.u.; p = 0.004), but this was not apparent in females (p = 0.544). When comparing global cerebral blood flow, there was a trend for lower flow in VAH+ compared with no VAH (p = 0.096).ConclusionWe demonstrated VAH prevalence to be around 28%, with similar prevalence in both males and females. VAH was associated with impaired regional flow and with elevated basilar artery cerebral pulsatility in males.

Correlation between Carotid Blood Flow Velocity and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease in Patients with Recent Small Subcortical Infarcts.

The common and internal carotid arteries are the upstream vessels of the small cerebral vessels. The relationship between hemodynamic changes in the significant cervical vessels and cerebral small vessel disease (CSVD) remains uncertain. This research sought to analyze the correlation between carotid blood flow velocity and the total magnetic resonance imaging (MRI) burden of CSVD in patients with recent small subcortical infarcts (RSSIs). Data were gathered from individuals diagnosed with RSSIs admitted to Changzhou Second People's Hospital between January 2022 and June 2023. Brain MRI was performed on every patient to determine the overall MRI burden of CSVD, along with carotid duplex ultrasound to evaluate carotid blood flow velocity and pulsatility index (PI) of the common carotid (CCA) and internal carotid (ICA) arteries. The association between carotid blood flow velocity and the total MRI load of CSVD was examined using univariate and multivariate analyses. For our investigation, 272 individuals with RSSIs were screened. 82 individuals had a moderate to severe load of CSVD, while 190 participants showed a mild burden. Patients with moderate to severe burden of CSVD had lower end-diastolic velocity (EDV) and higher PI in CCA and ICA than those with mild load (P < 0.001). After adjusting for variables like age, hypertension, systolic blood pressure, and blood homocysteine levels, multivariate logistic regression analysis showed that EDV in CCA (OR, 0.894; P = 0.011), PI in CCA (OR, 5.869; P = 0.017), EDV in ICA (OR, 0.909; P = 0.008), and PI in ICA (OR, 5.324; P = 0.041) were independently related to moderate to severe CSVD burden. Spearman correlation analysis showed that EDV in CCA and ICA was negatively related to the total MRI load of CSVD in patients with RSSIs (P < 0.001). PI in CCA and ICA was positively associated with the whole MRI load of CSVD (P < 0.001). Low carotid blood flow velocity and high carotid pulsatility index are independently associated with moderate to severe burden of CSVD.

Visit‐to‐visit blood pressure variability and medial temporal perfusion in APOE e4 homozygotes

AbstractBackgroundBlood pressure variability (BPV), independent of traditionally studied/targeted average blood pressure levels, is an emerging risk factor for cognitive impairment and Alzheimer’s dementia, possibly through links with cerebrovascular disease. Recent studies suggest vulnerability of the medial temporal lobes to tau accumulation and atrophy among individuals with elevated BPV, especially older APOE e4 carriers. Increased BPV has also been linked with lower cerebral blood flow (CBF) and perfusion decline in medial temporal regions, but it remains unclear how BPV and APOE e4 may interact to influence CBF. The aim of the current study was to determine whether the relationship between BPV and medial temporal lobe CBF varies by APOE e4 dose in older adults without dementia.Method105 older adults without dementia from the Alzheimer’s Disease Neuroimaging Initiative underwent 3‐4 blood pressure measurements between study baseline and 12‐months follow‐up and arterial spin labeling (ASL)‐MRI at 12‐months follow‐up or later (range: 0 – 84 months). Visit‐to‐visit BPV was calculated as variability independent of mean. CBF was determined for medial temporal regions (residualized by precentral [reference region] CBF), including hippocampus, parahippocampal gyrus, and entorhinal cortex. Venipuncture determined APOE e4 allele count (0 alleles: n = 71; 1 allele: n = 28; 2 alleles: n = 6). Multiple linear regression examined the interaction of BPV x APOE e4 dose on medial temporal CBF, controlling for age, sex, race/ethnicity, antihypertensive use, mean blood pressure, and cerebral metabolism (FDG‐PET).ResultElevated BPV was associated with lower CBF in entorhinal cortex (ß = ‐.96 [‐1.62, ‐.31]; p = .005) and parahippocampal gyrus (ß = ‐.63 [‐1.26, ‐.0002]; p = .049) in individuals with 2 APOE e4 alleles, whereas BPV was not significantly associated with CBF in these regions in individuals with 0 or 1 APOE e4 alleles (p’s &gt; = .08). There was no significant interaction of BPV x APOE e4 dose on hippocampal CBF.ConclusionHigher BPV is associated with lower medial temporal CBF in APOE e4/e4 carriers, suggesting BPV may be an understudied vascular risk factor for those at greatest genetic risk for Alzheimer’s disease, with potential therapeutic implications.

A comparative study of multi and single post labeling delay pseudocontinuous arterial spin labeling in patients with carotid artery stenosis

PurposeArterial Spin Labeling (ASL) allows for the non-invasive visualization of brain perfusion to detect abnormalities. In unilateral carotid artery stenosis, one hemisphere is less supplied with blood which results in a lower cerebral blood flow (CBF) compared to the healthy side. ASL can be performed time-resolved using multiple post labeling delay (PLD) times after labeling or static with a single delay, the latter allowing for a faster and more robust acquisition while bearing the risk of a falsely set delay resulting in unusable images. The purpose of this study is to compare the performance of multi-PLD and single-PLD ASL in patients with unilateral carotid artery stenosis both as means of diagnosis and therapeutic follow-up examination. MethodsASL perfusion data of 17 patients with known unilateral carotid artery stenosis was used to compare the diagnostic performance of the multi-PLD and single-PLD approach. Comparisons were made based on the CBF values and the added benefit of arrival time maps showing slower blood flow in multi-PLD ASL which might be overlooked in the individual delay images both before and after therapy. ResultsBoth the multi-PLD and the single-PLD data could identify the side of the stenosis with hemispheric differences in each approach (p < 0.001) and depict the normalization of CBF after therapy (p > 0.05). There were no differences between the individual methods (p > 0.05). ConclusionIn this work, we could show that multi-PLD ASL in patients with unilateral carotid artery stenosis is beneficial as it provides both CBF and arrival time maps, however when only a single-PLD acquisition is available, this appears sufficient in a clinical setting to investigate the presence of a unilateral stenosis.

Total and posterior cerebral blood flow is associated with white matter hyperintensity volume and Alzheimer’s‐like patterns of brain atrophy in older adults

AbstractBackgroundSmall vessel cerebrovascular disease, often visualized as white matter hyperintensities (WMH) on T2‐weighted MRI scans, contributes to risk, progression, and, possibly, pathogenesis of Alzheimer’s disease (AD). When considered in the context of previous neuroimaging biomarker work in AD, WMH appear to colocalize with other markers of disease risk and progression, including metabolic changes, atrophy, and tau pathology, in areas perfused by the posterior circulation. In the current study, we used a novel MR‐based method, termed phase contrast, to quantitate total cerebral blood flow in anterior and posterior circulations and test its relationship with WMH volume and an AD‐like pattern of brain atrophy in older, community‐dwelling adults.MethodTwo hundred forty‐five older adult participants (77±5.6 mean±SD age, 66% women, 42% Latinx, 30% Black, and 28% White individuals) in the Washington Heights Inwood Columbia Aging Project (WHICAP) received T1‐weighted, T2‐weighted (FLAIR), and phase contrast MR imaging. 2D phase contrast imaging can be used to quantify absolute blood flow rates with cross‐sectional velocity‐encoding of major vasculature leading into the brain. Blood flow rates in the anterior circulation (carotid arteries) and posterior circulation (vertebral arteries) were derived with Medis QFlow 4.0. WMH volume and cortical thickness in AD‐signature regions were derived with in‐house software and FreeSurfer v6.0, respectively. Separate general linear models tested the association of total, anterior, and posterior blood flow rates with WMH volumes and AD‐signature cortical thickness.ResultLower total cerebral blood flow was associated with increased total WMH volume (β = ‐0.14, p&lt;0.05, 95%CI [‐1.37E‐2, ‐7.32E‐4]), an effect that was stronger for posterior flow (β_posterior = ‐0.17, 95%CI [‐3.7E‐2, 2.5E3], β_anterior = ‐0.11, 95%CI [‐1.9E‐2, 5.4E3]). Lower posterior blood flow specifically was associated with lower AD‐signature cortical thickness, but only in older participants (age interaction term: β = ‐3.14, p&lt;0.01, 95%CI [‐2.0E‐4, ‐3.5E‐5]).ConclusionLower total cerebral blood flow, particularly in the posterior circulation, is associated with increased WMH volume and decreased cortical thickness, two neuroimaging markers that are implicated in risk and progression of AD. Future work that examines whether or how diminished total cerebral blood flow accounts for the colocalization of AD biomarkers across modalities will provide insight into the vascular contributions to AD.

Effects of Neonicotinoid Pesticide Metabolic Compounds on Medaka (Oryzias latipes) Embryo Development.

Neonicotinoids, including imidacloprid, are pesticides that resemble nicotine and undergo slight chemical alterations through metabolic changes in the environment. However, the effects of these metabolites on organisms remain unknown. In this study, we assessed the developmental processes of medaka embryos exposed to neonicotinoid metabolites. The target compounds were imidacloprid metabolites: 2-chloro-5-pyridine carbaldehyde (CPC) and 6-chloronicotinic acid (6-CNA). Medaka embryos within 6 h of fertilization were exposed to the compounds, and their developmental processes were observed under a stereomicroscope. Medaka embryos exposed to 5 mg/L CPC showed no abnormalities compared to the controls. Contrastingly, medaka embryos exposed to 10, 15, and 20 mg/L CPC showed abnormalities such as thrombus formation, asymmetry, disorganized development of the eyeballs, and low blood flow. This trend was more pronounced at higher CPC concentrations. On the other hand, embryos exposed to 80 and 160 mg/L 6-CNA showed no abnormalities until day 7 of exposure. However, on day 8 of exposure, sudden embryo death was observed. Both compounds may have bound to acetylcholine receptors as agonists; however, their effects were different. CPC caused abnormal development and 6-CNA caused inhibition of hatching gland development and/or synthesis of the hatching enzyme.

Blood flow restriction training improves the efficacy of routine intervention in patients with chronic ankle instability

As a new means of rehabilitation, blood flow restriction training (BFRT) is widely used in the field of musculoskeletal rehabilitation. To observe whether BFRT can improve the efficacy of routine rehabilitation intervention in patients with chronic ankle instability (CAI). Twenty-three patients with CAI were randomly divided into a routine rehabilitation group (RR Group) and a routine rehabilitation ​+ ​blood flow restriction training group (RR ​+ ​BFRT Group) according to the Cumberland Ankle Instability Tool (CAIT) score. The RR Group was treated with routine rehabilitation means for intervention, and the RR ​+ ​BFRT Group was treated with a tourniquet to restrict lower limb blood flow for rehabilitation training based on routine training. Before and after the intervention, the CAIT score on the affected side, standing time on one leg with eyes closed, comprehensive scores of the Y-balance test, and surface electromyography data of tibialis anterior (TA) and peroneus longus (PL) were collected to evaluate the recovery of the subjects. Patients were followed up 1 year after the intervention. After 4 weeks of intervention, the RR ​+ ​BFRT Group CAIT score was significantly higher than the RR Group (19.33 VS 16.73, p ​< ​0.05), the time of standing on one leg with eyes closed and the comprehensive score of Y-balance were improved, but there was no statistical difference between groups (p ​> ​0.05). RR ​+ ​BFRT Group increased the muscle activation of the TA with maximum exertion of the ankle dorsal extensor (p ​< ​0.05) and had no significant change in the muscle activation of the PL with maximum exertion of the ankle valgus (p ​> ​0.05). There was no significant difference in the incidence of resprains within 1 year between the groups (36.36% VS 16.67%, p ​> ​0.05). The incidence of ankle pain in the RR ​+ ​BFRT Group was lower than that in the RR Group (63.64% VS 9.09%, p ​< ​0.01). Therefore, four-weeks BFRT improves the effect of the routine intervention, and BFRT-related interventions are recommended for CAI patients with severe ankle muscle mass impairment or severe pain.

Relationship between myocardial strain, coronary microvascular dysfunction, and myocardial extracellular volume in patients with type 2 diabetes: a cross-sectional CMR study

Abstract Background Patients with diabetes often develop heart failure with preserved ejection and often demonstrate early indications of myocardial dysfunction by decreased strain, notably the global longitudinal (GLS). The underlying myocardial phenotypical changes in patients with diabetes are coronary microvascular dysfunction and myocardial interstitial fibrosis. The relation of these to strain-indicators of early systolic dysfunction is not established. Purpose We hypothesized that coronary microvascular function and interstitial fibrosis contribute to the subclinical myocardial dysfunction seen in patients with diabetes. Method With gadolinium contrast and adenosine-stress magnetic resonance imaging, we determined myocardial blood flow (MBF) and perfusion ratio (MPR) and extracellular volume (ECV; an imaging biomarker of diffuse fibrosis) in 211 patients with type 2 diabetes without macrovascular coronary artery disease and 25 control subjects. Left ventricular (LV) function was determined from its ejection fraction and 3D feature tracking of GLS, circumferential (GCS), and radial strains (GRS). Results Without a significant age- or sex-differences to control subjects, patients (median age 57 years [IQR 50, 67], 70% males) had a median diabetes duration of 12 [IQR 6, 18] years. LV ejection fraction was normal and similar to controls. Compared to control subjects (GLS -13.9±2.0%), GLS, GCS and GRS were reduced in the total diabetes cohort, and GLS was reduced also in the subgroup of patients without any diabetes complications (total -11.6±3.0%; without-complications -12.3±2.6%). GLS, but not GCS or GRS or LVEF, was associated with albuminuria (b (95%CI) 1.09 (0.22-1.96)) and autonomic neuropathy (b (95%CI) 1.43 (0.54-2.31)). Independently of ECV, a 10% increase in MBF at adenosine-stress and MPR was associated with improved GLS in uni- and multivariable regression analyses. A 10% increase in ECV was associated with a decrease in GLS in univariable and multivariable regression analysis, but this was abolished when adjusted for MPR. GLS showed a moderate ability to discriminate a significantly lowered myocardial blood flow at stress defined as &amp;lt;1.49 mL/min/g (AUC 0.72, GLS threshold -11.5%; sensitivity 75% and specificity 53%) and myocardial perfusion ratio defined as as &amp;lt;2.1 (AUC 0.73, GLS threshold -10.8% resulted in a sensitivity of 71% and a specificity of 70%). GLS had a poor ability to predict increased extracellular volume defined as &amp;gt; 31% (AUC 0.60, GLS threshold -13.5 resulted in a sensitivity of 72% and a specificity of 34%). Conclusion Of the two important phenotypical changes seen with type 2 diabetes, microvascular dysfunction and fibrosis, coronary microvacular dysfunction demonstrates the more important relation to early systolic compromise as determined from the left ventricle global longitudinal strain.Associations of Systolic parametersROC curve

Predictive Effects of Platelet Indices in Cirrhotic Patients with or without Portal Vein Thrombosis

Objective: Portal vein thrombosis (PVT) is a common finding in liver cirrhosis. Besides low portal blood flow, thrombophilia, bacterial translocation and endotoxemia, platelets which are considered as important source of prothrombotic agents may play a role in thrombotic events in cirrhosis. Large platelets have been reported to have numerous granules that result in greater thrombotic and proinflammatory activity. We aimed to define the role of platelet indices in PVT among cirrhotic patients. Method: Cirrhotic patients admitted to Gastroenterology Clinic and having a dynamic radiological examination were assessed retrospectively. Demographic and laboratory findings were recorded including platelet distribution width (PDW) and mean platelet volume (MPV). Severity of cirrhosis was assessed with MELD (Model for End Stage Liver Disease) and Child-Pugh-Turcotte (CPT) scores Results: Study included 255 patients. Mean age was 60.6±10.2 years. 41.6% of patients were female. 50 (19.6%) patients had PVT. Patients with PVT did not differed from those without PVT in age, gender and presence of diabetes mellitus. Median platelet count was lower in patients with PVT (100 (22-370) vs 79,5 (22-573), p: 0,033). Mean MPV and PDW levels were similar between PVT and non-PVT groups (p &gt;0.05). Although median MELD scores did not differ between groups, median CPT scores were significantly higher in PVT compared to non-PVT group (p:0,027). Conclusion: Cirrhotic patients with PVT had more prominent thrombocytopenia, but similar MPV and PDW levels compared to those without PVT.

Abstract 222: Real Time Feedback of Chest Compressions by Hands-Free Carotid Doppler in a Porcine Model

Background: Real-time hemodynamic feedback devices provide information on cardiopulmonary resuscitation (CPR) quality. This can improve hand positioning and technique, thereby maximizing blood flow and potentially improve survival. Hypothesis: We hypothesize that a newly developed hands-free Doppler for carotid blood flow velocity (RescueDoppler, RD), can identify optimal vs. suboptimal chest compression sites during CPR. Aim: To assess the potential of the RD device to continuously monitor the effect of each compression by ultrasound metrics and waveforms in a porcine model. Methods: Ventricular fibrillation was induced in 5 pigs using an ICD. Manual CPR (blinded for hemodynamic data) was performed for 10 seconds at 3 different compression sites in random order (Fig.), and repeated 6 times. We analyzed ultrasound waveforms with Time Average Velocity (TAV) in a linear mixed model with site as fixed effect, and animal and site within animal as random effects. We further compared TAV to invasive systolic blood pressure (SBP) from the contralateral carotid artery. Results: Data from 5 pigs (mean weight 31.2 kg) and 29 of 30 sequences were included. Overall, blood flow velocity was highest at compression site 2 (TAV 33 cm/s, P&lt;0.01), but there was significant variability (P&lt;0.01) in animals (SD= 3.7) and at sites within animal (SD= 7). A compression site yielding the highest TAV (range 19 to 48 cm/s) or lowest TAV (6-25 cm/s) was successfully identified in all animals with corresponding SBPs 50-81 mmHg, and 46-64 mmHg, respectively. The correlation between TAV and SBP was 0.62-0.90 within animals. Conclusions In this animal study, a newly developed hands-free Doppler enabled assessment of blood flow velocity during CPR and detected significant variation according to chest compression site. RD identified the sites with both high and low blood flow velocities and is thus a promising device for effectively identifying the optimal and suboptimal chest compression sites during CPR.

Transit-time flowmetry measurement features of coronary bypass grafts after multiple percutaneous coronary interventions

The functionality of coronary bypass grafts after surgical myocardial revascularization in patients with coronary heart disease directly depends on the state of the target coronary arteries. In the presence of widespread and diff use atherosclerotic lesions or microcirculatory dysfunctions, a high frequency of coronary bypass dysfunctions is noted in the near future. In some cases, shunt dysfunction can lead to severe hemodynamic instability, accompanied by acute circulatory disorders.Aim: To assess the function of coronary bypass grafts during myocardial revascularization using the method of ultrasonic flowmetry in patients with and without a history of multiple percutaneous coronary interventions (PCI).Material and methods. The retrospective study included 47 patients who underwent coronary artery bypass surgery. A total of 145 coronary bypass grafts were performed. All patients were divided into 2 groups. Group 1 (PCI group) included patients after multiple previous PCI (n = 25; 74 coronary bypass grafts), group 2 (without PCI) included patients without previous PCI (n = 22; 71 coronary bypass grafts). All patients underwent intraoperative ultrasonic flowmetry of coronary bypass grafts using the VeriQ system (Medistim, Norway).Results. When analyzing the status of coronary bypass grafts in patients after multiple PCI, a significantly low mean volumetric blood flow rate was noted (29.5 ± 8.3 ml/min and 48.2 ± 11.6 ml/min, respectively, p = 0.0001) and lower diastolic filling (55.2 ± 8.2% and 71.9 ± 7.1%, p = 0.0001). Also in the group of patients after multiple PCI, there were 2 (2.7%) cases of revision of the distal anastomosis due to a high pulsatile index and low volumetric blood flow velocity. However, no such events were noted in the group without PCI.Conclusions. Previous percutaneous coronary interventions are compromising factors for the state of the coronary bed, which reduces the functional status of coronary bypass grafts and may increase the perioperative risk of surgical myocardial revascularization.

Clinical study of 16 patients with thalamic infarction

AbstractBackgroundThe pathophysiology of sensory impairment in thalamic infarction is unclear.AimThe association between extents of lesions in the ventroposterior nucleus (VP) and distributions of sensory impairments after thalamic infarction was studied.MethodsNeurological symptoms and locations of lesions in 16 patients with thalamic infarction were analyzed. Locations of lesions were grouped into the four regions (region 1–4) in the front to back direction.ResultsThe lateral part of the region3 within the intermediate to caudal levels where the VP exists was frequently involved. Subjective superficial sensory impairments were noted in eight patients. The other six patients showed objective sensory impairment alone. The most frequent type was the face/arm in 6 patients. In these six patients, sensory impairments were distributed to the distal part of the arm and the mouth surrounding in five patients each. Sensory impairments were distributed to the half of the body in four patients, the face/trunk/arm in one patient, the face/arm/leg in two patients, and the arm in one patient.ConclusionsThe principal inferolateral branch supplies the VP and has no anastomosis. In ischemic conditions, blood flow can be decreased in the inside part of the VP, which corresponds to the field of the hand and the mouth surrounding. The detection threshold of superficial sensations for hand and mouth is low. These phenomena were associated with frequent involvement limited to the face/arm. Distributions of sensory impairments were considered to depend on the detection threshold and the lower blood flow in the inside part.

Acute upper and lower limb hemodynamic responses during single sessions of low- versus high-intensity inspiratory muscle strength training.

Inspiratory muscle strength training (IMST) has shown potential to improve both respiratory and cardiovascular function in health and disease. Less is known about acute hemodynamic responses to a single IMST session, therefore we assessed upper and lower limb blood flow via Doppler ultrasound in the brachial and popliteal arteries, respectively. Mean, anterograde, and retrograde blood flow (BF) and shear rate (SR) were assessed relative to baseline during low-intensity (15% maximal inspiratory pressure - PImax) and high-intensity (75% PImax) IMST. During low-intensity IMST, popliteal BF and SR were reduced by ∼10%, and brachial BF and SR were reduced by ∼40%. During high-intensity IMST, popliteal BF and SR were reduced by ∼20%, and brachial BF and SR were reduced by ∼35%. BF and SR responses were not statistically different between low-intensity and high-intensity training for either blood vessel (P > 0.05). In addition, anterograde BF and SR were significantly decreased in the brachial artery for both low-intensity and high-intensity training (P < 0.05), but not the popliteal artery (P > 0.05). Finally, during IMST retrograde BF and SR were significantly increased in both the upper and lower limbs during low-intensity and high-intensity training (P < 0.05). These data provide novel insight into the acute BF and SR responses to a single bout of IMST and may enhance our understanding of the mechanism(s) by which IMST imparts its beneficial chronic effects on cardiovascular function.NEW & NOTEWORTHY Herein, we demonstrate for the first time that upper and lower limb blood flow and shear rate patterns are altered during a single bout of IMST, at low- and high-intensity training. Specifically, anterograde blood flow and shear rate are significantly reduced in the brachial artery, whereas retrograde blood flow is significantly elevated in both the brachial and popliteal arteries. These findings provide insight into the vascular impact of IMST, which may inform future mechanistic studies.

Safety and Metabolic Tolerance of Citrate Anticoagulation in Critically Ill Polytrauma Patients with Acute Kidney Injury Requiring an Early Continuous Kidney Replacement Therapy.

For severe polytrauma patients with an early AKI requiring renal replacement therapy, anticoagulation remains a great challenge. Due to a high bleeding risk, hemodynamic instability, and increased lactate levels, continuous modality (CKRT) and citrate anticoagulation seem to be the most appropriate. However, their safety with regard to the potential risk of impaired citrate metabolism is not documented. A retrospective study of 60 severe polytrauma patients admitted to the emergency department between January 2000 and December 2021 was conducted; the patients requiring CKRT during the first 72 h were treated with citrate (n. 46, group Citrate) or with heparin (n. 14, group Heparin). Out of 60 patients, 31 survived (51.7%). According to logistic regression analysis, age and SOFA score were significant predictors of mortality. The incidence of rhabdomyolysis was more common in the survivors (77.4 vs. 51.7%), and Kaplan-Meyer analysis showed a better trend towards survival at 90 days for the group Citrate than the group Heparin (p 0.0956). In the group Citrate, hemorrhagic episodes were significantly less common (0.045 vs. 0.273 episodes/day, p < 0.001); the effective duration (h/day) of CKRT was longer; and the effective net ultrafiltration rate (mL/kg/h) and blood flow rate were lower. For severe polytrauma patients, early, soft CKRT with citrate anticoagulation at a low blood flow rate and circuit citratemia showed a better safety and hemodynamic stability, suggesting that citrate should be the first choice anticoagulant in this subset of patients.

Carbohydrate ingestion attenuates the reduction in complex cognitive function and cerebral blood flow during prolonged passive heat stress in humans

PurposeTo determine whether carbohydrate ingestion would reduce cognitive dysfunction in humans following long duration passive heat stress (PHS) versus consuming electrolytes alone. MethodsFifteen young (27 ± 4 y) healthy adults were exposed to 120 min of PHS through the use of a liquid perfused suit (50 °C) on two randomized visits. Subjects consumed fluids supplemented with electrolytes (E) or electrolytes + carbohydrates (E + C). Pre- and post-heat stress, body mass (BM) and plasma osmolality (pOsm) were measured. Heart rate (HR), blood pressure (BP), Physiological Strain Index (PSI), core temperature (Tc), plasma glucose, respiration rate (RR), end-tidal CO2 (PetCO2) and internal carotid artery (ICA) blood flow were recorded at baseline and every 15 min of heat stress. Cognitive function was assessed via the Automated Neuropsychological Assessment Metric at baseline and at 30- and 120 min during heat stress. ResultsThere were no significant differences between fluid conditions for BM, pOsm, PSI, Tc, RR or PetCO2. Plasma glucose was ∼75% greater in the E + C condition compared to the E condition after 90 min of PHS (P < 0.05). Cognitive function (120 min) was impaired following PHS only in E condition (P < 0.05) and performance on complex cognitive tasks were better by ∼22–340% in the E + C vs. E (P < 0.05). Compared to the E condition, HR and BP were lower and ICA blood flow, vascular conductance, and glucose delivery was ∼90% greater in the E + C after 90 min of PHS (P < 0.05). ConclusionsThese data are the first to demonstrate that carbohydrate ingestion may have a protective effect on cognitive function during long duration PHS. Furthermore, this protection was associated with preserved ICA blood flow and glucose delivery to the brain.

Lung ultrasound score for monitoring the withdrawal of extracorporeal membrane oxygenation on neonatal acute respiratory distress syndrome

BackgroundExtracorporeal membrane oxygenation (ECMO) is considered an efficient and life-saving treatment for neonatal severe acute respiratory distress syndrome (ARDS). Bedside lung ultrasound (LUS) is an attractive and feasible method for evaluating neonatal ARDS. ObjectiveTo evaluate the value of LUS score at veno-arterial (V-A) ECMO withdrawal in neonatal patients with severe acute ARDS. MethodsA retrospective preliminary study was conducted in our cardiac intensive care unit from June 2021 to June 2022. Eight severe ARDS neonates who received V-A ECMO were enroled in this study. LUS was measured daily during ECMO and when weaning off ECMO. The relationships between the LUS score and ECMO parameters (blood flow and the sweep gas of FiO2) were assessed. Results(1) There was a significant improvement in LUS score by ECMO treatment. And, various diagnostic signs of lung ultrasound were detected during ECMO, including pulmonary edema (7 neonates) and lung consolidation (4 neonates), followed by pleural effusion (1 neonate) and bilateral white lung (1 neonate). (2) A total of 12 trials for weaning off ECMO were carried out, of which four failed, but all eight neonates finally succeeded in passing the weaning trial. LUS score of 21 or less was defined as a cut-off value for predicting ECMO weaning success. During ECMO treatment, LUS score was positively correlated with ECMO blood flow (r = 0.866, P < 0.05). ConclusionsLUS can be used to evaluate the various lung diagnostic signs in ARDS neonatal patients during ECMO treatment, and the LUS score under ECMO treatment decreases over time. The reduction in LUS score is associated with lower ECMO blood flow. LUS score is regarded as a predictor of ECMO weaning success.

The Brainstem Cavernoma Case Series: A Formula for Surgery and Surgical Technique.

Background and Objectives: Cavernous malformations (CM) are vascular malformations with low blood flow. The removal of brainstem CMs (BS) is associated with high surgical morbidity, and there is no general consensus on when to treat deep-seated BS CMs. The aim of this study is to compare the surgical outcomes of a series of deep-seated BS CMs with the surgical outcomes of a series of superficially located BS CMs operated on at the Department of Neurosurgery, College of Tuebingen, Germany. Materials and Methods: A retrospective evaluation was performed using patient charts, surgical video recordings, and outpatient examinations. Factors were identified in which surgical intervention was performed in cases of BS CMs. Preoperative radiological examinations included MRI and diffusion tensor imaging (DTI). For deep-seated BS CMs, a voxel-based 3D neuronavigation system and electrophysiological mapping of the brainstem surface were used. Results: A total of 34 consecutive patients with primary superficial (n = 20/58.8%) and deep-seated (n = 14/41.2%) brainstem cavernomas (BS CM) were enrolled in this comparative study. Complete removal was achieved in 31 patients (91.2%). Deep-seated BS CMs: The mean diameter was 14.7 mm (range: 8.3 to 27.7 mm). All but one of these lesions were completely removed. The median follow-up time was 5.8 years. Two patients (5.9%) developed new neurologic deficits after surgery. Superficial BS CMs: The median diameter was 14.9 mm (range: 7.2 to 27.3 mm). All but two of the superficial BS CMs could be completely removed. New permanent neurologic deficits were observed in two patients (5.9%) after surgery. The median follow-up time in this group was 3.6 years. Conclusions: The treatment of BS CMs remains complex. However, the results of this study demonstrate that with less invasive posterior fossa approaches, brainstem mapping, and neuronavigation combined with the use of a blunt "spinal cord" dissection technique, deep-seated BS CMs can be completely removed in selected cases, with good functional outcomes comparable to those of superficial BS CM.