Decrease In Blood Flow Velocity Research Articles

Pre- and postganglionic vasomotor dysfunction causes distal limb coldness in multiple system atrophy

BackgroundThe detailed pathophysiology of limb coldness in multiple system atrophy (MSA) is unknown. MethodsWe evaluated cutaneous vasomotor neural function in 18 MSA patients with or without limb coldness, and in 20 healthy volunteers as controls. We measured resting skin sympathetic nerve activity (SSNA) and spontaneous changes of the sympathetic skin response (SSR) and skin blood flow (skin vasomotor reflex: SVR), as well as SVR and reflex changes of SSNA after electrical stimulation. The parameters investigated were the SSNA frequency at rest, amplitude of SSNA reflex bursts, absolute decrease and percent reduction of SVR, recovery time, and skin blood flow velocity. ResultsBoth the resting frequency of SSNA and the amplitude of SSNA reflex bursts were significantly lower in the MSA group than the control group (p<0.001 and p<0.05, respectively). There were no significant differences between the two groups with regard to the absolute decrease or percent reduction of SVR volume. The recovery time showed no significant difference between all MSA patients and control groups, but it was significantly prolonged in six MSA patients with limb coldness compared with that in the control group and that in MSA patients without limb coldness (p<0.01). The skin blood flow velocity was significantly slower in the MSA group than in the control group (p<0.001). ConclusionIn MSA patients, limb coldness might occur due to impairments of the peripheral circulation based on prolongation of vasoconstriction and a decrease of skin blood flow velocity secondary to combined pre- and postganglionic skin vasomotor dysfunction.

Intravascular application of electrocautery in a rabbit model of abdominal aortic endarterectomy.

Effective therapies for preventing perioperative complications such as thrombosis and inflammation after coronary endarterectomy (CE) are lacking. Electrocoagulation electrotomes have been routinely used in surgery for their cutting, clotting, and hemostatic properties. As strong flattening tools, their electrocautery function may prevent mechanical intimal-adventitial injury to arterial circulation and attenuate stenosis. The present study investigated the effects of intravascular application of electrocautery on ameliorating inflammation and thrombosis in a rabbit model of abdominal aortic endarterectomy. New Zealand rabbits were randomly divided into the sham, control (endarterectomy), and study (endarterectomy + electrocautery) groups with 10 in each group. Abdominal aortas were partially blocked and intima was removed. Electrocautery was performed with an electrocoagulation electrotome through the entire blocked vessel lumen. Vascular ultrasound parameters, molecular biological and histological characteristics of the abdominal aorta including vascular diameter, blood flow velocity, serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and apoptosis rate of vascular endothelial cells (ECs) were evaluated postoperatively by vascular Doppler ultrasound, ELISA, real-time RT-PCR, flow cytometry, and immunofluorescence at various time points. Compared with the endarterectomy + electrocautery group, the isolated endarterectomy group had significantly increased levels and gene expression of TNF-α and IL-6 (P<0.05), and rates of apoptosis of vascular ECs (P<0.05), with gradual vascular stenosis and decreased blood flow velocity. In conclusion, intravascular application of electrocautery has favorable short-term effects on the abdominal aorta and can reduce inflammation in a rabbit model of abdominal aorta endarterectomy. Long-term anti-inflammatory and anti-thrombotic effects on arterial remodeling and the clinical value of electrocautery in CE remain to be determined.

Measurement of Blood Flow Velocity in the Middle Cerebral Artery During Spontaneous Migraine Attacks: A Systematic Review.

To assess the evidence for blood flow velocity changes in the middle cerebral artery during and outside of spontaneous migraine attacks. A systematic literature search on PubMed was performed and reference lists of assessed articles to identify studies on spontaneous migraine attacks that used transcranial Doppler on the middle cerebral artery with comparisons to interictal measurements were reviewed. Studies on non-spontaneous attacks and intervention studies were excluded. A total of 17 original articles reporting blood flow velocity values in the middle cerebral artery using transcranial Doppler in migraine patients both with and without aura were identified. A total of 24 subgroups (ie, migraine patients without aura = 11, migraine patients with aura = 9, and mixed = 4) of migraine patients were investigated during and outside spontaneous migraine attacks in the 17 studies. No change was reported in 15 subgroups (63%), while decreased blood flow velocity was found in 8 subgroups (33%) and increased blood flow velocity was found in one study (4%). Exploratory analysis revealed that studies showing decreased blood flow velocity were carried out earlier after onset of attack (mean time, 4.1 h) compared with those showing no change (mean time, 6.0 h). Overall, spontaneous migraine attacks are not accompanied by blood flow velocity changes in the middle cerebral artery. However, explorative analyses on the time from attack onset to examination revealed side-specific attack-related decrease in blood flow velocity in the early, but not late phases. This is the first systematic review focusing on the flow changes in the middle cerebral artery of spontaneous migraine attacks. Future studies should focus on the early blood flow velocity changes in migraine attacks.

СЛУЧАЙ УСПЕШНОЙ РЕВАСКУЛЯРИЗАЦИИ ПОЧКИ МЕТОДОМ АОРТО-ПОЧЕЧНОГО ШУНТИРОВАНИЯ

The article describes the case of successful revascularization of the right kidney by the method of autovenous aortorenal shunting. According to the data of renal duplex scanning, the patient showed signs of a size reducing of the right kidney with a decrease in blood flow velocity and resistance indices in the renal artery. Results of spiral computed tomography demonstrated the subtotal stenosis of the right renal artery up to 95% and preservation of the excretory function of the kidney. During the angiography an occlusion of the proximal segment of the right renal artery was detected, and an attempt of recanalization for subsequent stenting was failed. As a consequence, an open revascularization – autovenous aortorenal shunting was performed using laparotomy access. In the short- and mid-term periods, normalization of arterial pressure and satisfactory patency of the autovenous shunt were noted. In the opinion of the authors, in case of obliteration of the proximal segment of the renal artery caused by arteritis, open revascularization is a procedure of choice that provides radical restoration of the main blood circulation of the organ.

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.

Endothelin a Receptor (ETRA) Blockade Inhibits Leukocyte Adhesion to the Vascular Endothelium in Sickle Cell Disease

▪Objective:Recurrent acute episodes of vaso-occlusion (VOC) are one of the hallmarks of sickle cell disease (SCD). Leukocytes are in an activated state in SCD and their recruitment to the vascular endothelium marks a critical event in the pathophysiology of the vaso-occlusive process. Endothelin-1 (ET-1), a potent vasoconstrictive and pro-inflammatory endogenous peptide, is elevated in steady state SCD, increases during acute VOC crisis, and remains elevated post crisis. This study asked whether the ET-1-ETRA signaling pathway is involved in promoting leukocyte adhesion in a hypoxia-reoxygenation challenged mouse model of SCD. Secondly, we wondered whether ET-1 is able to directly activate and increase the proadhesive phenotype of the peripheral leukocyte population.Methods: Animals:We used the UAB knockout-transgenic mouse model of SCD for our studies (Ryan, 1997). Experimental groups consisted of homozygous (SCD-/-), heterozygous (SCD+/-), and C57BL/6 control mice. Intravital Microscopy:Bosentan (BOS; dual ETRA/B antagonist) or Ambrisentan (AMB; specific ETRA antagonist) was administered by medicated chow for 8 weeks. Prior to imaging, animals were exposed to 5 hrs of 8% O2 followed by 2 hrs of reoxygenation in room air. Leukocytes were stained in vivo with a PE-conjugated anti-CD45 antibody. Mice were anesthetized and the calvarial bone marrow microvascular network was observed using an intravital microscope with water-immersion objectives. Images were analyzed off-line for leukocyte velocity, adhesion, and flow dynamics (Image Pro-Plus 5.0). Superoxide/Cytokine/Integrin measurements: Leukocytes were isolated from freshly harvested peripheral blood (SCD-/- and controls) and exposed to ET-1 or vehicle. ROS production was measured by luminescence (Lumistar Galaxy Luminometer). Intracellular cytokine and surface integrin expression was analyzed by flow cytometry. Neutrophil Adhesion Assay: Peripheral neutrophils were purified by a Ficoll gradient from SCD-/- mice and controls. Following ex vivo incubation with ET-1 or vehicle, the purified neutrophils were added to pre-activated (thrombin) rat PMVECs. After washing with PBS, the cells were fixed and stained with MPO to identify adherent neutrophils.Results: Intravital microscopy revealed that ETR blockade with BOS, but not AMB, enhanced WBC rolling and adhesion at steady state without altering flow velocity, suggesting an important role for ETRB signaling at baseline in SCD-/- animals. Following a hypoxia/reoxygenation protocol, both antagonists were equally effective in decreasing WBC rolling and adhesion in SCD-/- animals. Both ETR antagonists were able to correct H/R-induced decreases in blood flow velocity to near baseline values. Next we asked if ET-1 is capable of activating WBCs by first measuring levels of receptor mRNA in sorted peripheral neutrophils and monocytes. Next we measured intracellular cytokine, surface integrins and ROS production following ex vivo exposure to ET-1. Results indicated a very low amount of ETRA mRNA in neutrophils of SCD-/- mice and controls. ETRB mRNA was predominantly expressed in monocytes of SCD-/- mice. ET-1 ex vivo stimulation failed to increase cytokine, integrin and ROS levels beyond baseline in sickle neutrophils and monocytes. Functionally, more neutrophils from SCD-/- mice adhered to pre-activated endothelial cells than controls; however, ex vivo ET-1 stimulation failed to increase adhesion.Summary and Conclusions: Our results demonstrate that selective ETRA blockade is sufficient to abrogate H/R-induced leukocyte-endothelial interactions in a preclinical model of SCD. While the dual ETRA/B antagonist produced similar results after H/R, its proadhesive effect at steady state suggests an important role for the endothelin B receptor under baseline conditions. Although the long-term significance of these findings remains to be elucidated, at this early stage our results suggest a potential therapeutic advantage for a selective ETRA treatment strategy in SCD. The lack of response of the leukocyte population to direct ET-1 stimulation suggests that ET-1 targets primarily the vascular endothelium to promote leukocyte adhesion. In conclusion, this study established a potentially important role for clinically available ETRA antagonists in the treatment portfolio for patients with SCD. DisclosuresGutsaeva:Grifols: Research Funding.

СОСТОЯНИЕ ПОРТО-ПЕЧЁНОЧНОЙ ГЕМОДИНАМИКИ ПРИ ПЕЧЁНОЧНОЙ НЕДОСТАТОЧНОСТИ У БОЛЬНЫХ ДЕСТРУКТИВНЫМ ПАНКРЕАТИТОМ

Extraorgan complications of acute destructive pancreatitis are registered in 60–95% of patients. Liver failure is regis-tered in one of the four patients with pancreatic necrosis. We analyzed the results of surgical treatment of 122patients with acute destructive pancreatitis. We studied clinical indicators of liver failure in 103(84.4%) patients with acute pancreatitis. The development of portal hypertension with decrease in hepatic volume perfusion is an important ele-ment in the pathogenesis of acute pancreatitis and associated liver function abnormalities. In patients with severe and moderate liver failure, the reduction of blood flow in portal vein was registered. It was caused by reduce of portal vein diameter and decrease in linear blood flow velocity. Destructive pancreatitis is accompanied by liver failure with hyperbilirubinemia, increased activity of cytolytic enzymes, incoordination in protein and carbohydrate metabolism as its common manifestations. An important factor in the pathogenesis of liver failure is a reduction of porto-hepatic hemodynamics and as a consequence – hepatic hypoperfusion.

Analysis of the causes of age-related decline in the velocity of cerebral blood flow

Goal. Determining the causes of age-related decrease of blood flow velocity (BFV) in the middle cerebral artery (MCA) in healthy subjects and in patients during surgical lengthening of stunted limbs. Methods. BFV in MCA was determined by transcranial Doppler. The analysis of the indicator in functional muscle sample of 30 healthy people 18-60 years old and 30 patients 3-62 years of lagging in the growth of one of the lower limbs in the course of its operational extension. As an indicator of cerebral autoregulation used swing changes BFV indicators during the second holding muscle functional test. Results. The age-related reduction in flow rate in the middle cerebral artery was more pronounced in patients with disorders of the musculoskeletal system. At the same time, the average value of the magnitude of blood flow velocity index changes during the functional test in healthy individuals older than 10 years, as well as in patients before treatment and during the fixation is stable (17-25 %). Conclusion. Age-related decline in the BFV at MCA is a prerequisite for the preservation of cerebral autoregulation. Disorders of cerebral autoregulation in patients undergoing distraction of limbs greatly reduces their tolerance to physical exercise.

Ge-Gen Decoction attenuates oxytocin-induced uterine contraction and writhing response: potential application in primary dysmenorrhea therapy

The uterine tetanic contraction and uterine artery blood flow reduction are possible reasons for primary dysmenorrhea (PD). In the present study, we aimed to evaluate the uterine relaxant effect and the influence on uterine artery blood velocity of Ge-Gen Decoction (GGD), a well-known Chinese herbal formula. In female ICR mice, uterine contraction was induced by oxytocin exposure following estradiol benzoate pretreatment, and the uterine artery blood velocity was detected by Doppler ultrasound. Histopathological examination of the uterine tissue samples were performed by H&E staining. Ex vivo studies demonstrated that oxytocin, posterior pituitary, or acetylcholine induced contractions in isolated mouse uterus. GGD inhibited both spontaneous and stimulated contractions. In vivo study demonstrated that GGD significantly reduced oxytocin-induced writhing responses with a maximal inhibition of 87%. Further study demonstrated that GGD normalized oxytocin-induced abnormalities of prostaglandins F2 alpha (PGF2α) and Ca2+ in mice. In addition, injection of oxytocin induced a decrease in uterine artery blood flow velocity. Pretreatment with GGD reversed the oxytocin response on blood flow velocity. Histopathological examination showed pretreatment with GGD alleviated inflammation and edema in the uterus when compared with the model group. Both ex vivo and in vivo results indicated that GGD possessed a significant spasmolytic effect on uterine tetanic contraction as well as improvement on uterine artery blood velocity which may involve PGF2α and Ca2+ signaling, suggesting that GGD may have a clinic potential in PD therapy.

Studentų požiūrio į energinių gėrimų vartojimą ir poveikį organizmui analizė

Reikšmingas energinių gėrimų pardavimo padidėjimas įvyko 2005 – 2006 metais, kuomet pasirodė pirmieji alkoholio ir energinių gėrimų kokteiliai. Minėtuoju laikotarpiu šie gėrimai ėmė populiarėti ir Lietuvoje. Energinių gėrimų populiarumas tarp jaunimo didėja. Tyrimai rodo, kad energinių gėrimų vartojimas dažnai yra susijęs su fizine ir psichine sveikata. Į energinių gėrimų sudėtį įeina įvairiausių medžiagų - taurinas, guarana, karnitinas, ginsenozidų, dekstrozė, inozidolis, vitaminai B6 ir B12 - visos jos išsiskiria tonizuojančiu poveikiu. Tyrimuose pateikti duomenys rodo, jog energinių gėrimų vartojimas yra potencialiai žalingas dėl papildomo širdies darbo krūvio ir sumažėjusio smegenų kraujotakos greičio. Darbo tikslas buvo įvertinti studentų žinias apie energetinių gėrimų daromą poveikį ir išanalizuoti šių gėrimų vartojimo priežastis. Tyrimas buvo atliktas 2011- 2015 metais Lietuvos sveikatos mokslų universitete (LSMU) ir Kauno kolegijoje (KK). Apklausta LSMU 200 I – III kursų ir KK 100 I – III kursų studentų, kurių amžius 19 – 22 metai. Studentai buvo tiriami apklausos metodu, atliekant anketinę apklausą raštu. Klausimai – uždarojo ir atvirojo tipo, su pasirenkamais atsakymais. Energinius gėrimus vartojo daugiau nei pusė apklausoje dalyvavusių studentų. Manome, kad jie reprezentuoja studentų populiacijos tendencijas. Tarp 19 – 22 metų jaunimo energinių gėrimų vartojimas nėra susijęs su fizinio aktyvumo skatinimu. Tokius gėrimus vartojantys studentai juos renkasi siekdami didinti protinį aktyvumą. Jaunuoliai, vartojantys energinius gėrimus, nevienareiškmiškai vertina veiksnius, darančius įtaką energinio gėrimo vartojimo pasirinkimui. Jaunuoliai žino apie energinių gėrimų neigiamą poveikį.

Doppler imaging of orbital vessels in the assessment of the activity and severity of thyroid-associated orbitopathy.

Patients with symptoms of thyroid-associated orbitopathy are classified on the basis of the clinical activity score (CAS) proposed by Mourits in 1989. Despite its undoubted clinical usefulness, it has several limitations which can decide about the success or failure of the implemented treatment. Numerous reports mention the presence of hemodynamic changes in orbital and bulbar vessels in the course of an orbitopathy called Graves’ disease. The usage of Doppler sonography in the diagnosis of numerous ophthalmologic vascular diseases suggests that changes in thyroid-associated orbitopathy can correlate with the activity and severity of the disease. This paper presents the overview of the state-of-the-art concerning the usefulness of Doppler imaging in patient selection for the treatment of thyroid-associated orbitopathy. It has been shown that the velocity of blood flow in the superior ophthalmic vein, which is the most susceptible to changes in anatomical conditions in the enclosed orbital space, decreases in a statistically significant way. A decrease in blood flow velocity is closely associated with the active stage of the disease whereas reverse flow or its absence attest to severe orbitopathy and constitute a risk factor of ocular neuropathy. The activity of the inflammatory process in the eyeball is also confirmed by an increase in peak systolic velocity (PSV) in the ophthalmic artery and central retinal artery as well as end-diastolic velocity (EDV) in the ophthalmic artery. Resistance index values decrease in the ophthalmic artery and increase in the central retinal artery mainly in cases with considerable expansion of the extraocular muscles.

Glaucoma patients have a significant decrease in retrobulbar blood flow velocities during general anesthesia

PurposeGlaucoma patients are known to have an underlying vascular dysfunction and General anesthesia (GA) significantly decreases blood pressure, which might decrease ocular perfusion. This study was conducted to investigate the effects of GA on ophthalmic flow velocities and blood pressure.MethodsProspective, case‐control study. Glaucoma patients were scheduled for trabeculectomy or drainage device implantation; non‐glaucomatous patients undergoing vitrectomy for macular hole or epiretinal membrane peeling were recruited as control subjects. Color Doppler imaging of the ophthalmic artery (OA) was performed immediately before and 1 minute after GA induction. The following parameters were analyzed: OA blood velocities and resistivity index, as well as cardiovascular parameters (diastolic and systolic blood pressure and heart rate). Statistical analysis was performed using Student’s paired t test, Mann‐Whitney, Fisher's exact test and Spearman's correlation.Results53 patients were included (glaucoma group: 25; control group: 28). The magnitude in blood pressure decrease after GA induction was similar between the two groups (p value 0.61–0.70). However, the decrease in OA blood velocities was significantly larger in the glaucoma groups than in the control group (p &lt; 0.03 in all comparisons). Unlike the control subjects, in the glaucoma group there was a significant association between the magnitude of blood pressure decrease and the lowering of the OA mean blood velocity (r = 0.69, 95% IC: 0.36–0.87, p &lt; 0.001).ConclusionsThese results suggest that glaucoma patients are unable to keep a stable blood velocity in the OA when subjected to acute significant decreases in blood pressure (such as the ones seen after GA induction).

Brain blood flow and hyperventilation on cold water immersion: can treading water help control these symptoms of cold shock?

Cold-water immersion (CWI) elicits the cold shock response (CSR). The hyperventilatory component of the CSR causes a decrease in cerebral blood flow velocity (CBFv) potentially causing sensations of dizziness and increasing the risk of becoming unconscious and consequently drowning [1]. In these early minutes of CWI the current advice is to 'float first' and remain stationary [2] yet this strategy may not have any effect on ventilation and therefore brain CBFv. We tested the hypothesis that leg only exercise could offset the reduction in CBFv in a resting CWI (H1) and be absent in warm water immersion.

Anterior segment neovascularization in diabetic retinopathy: a masquerade.

PurposeAnterior segment neovascularization (ASNV) could be a masquerade for ocular ischemic syndrome (OIS) in diabetic patients which misleads diagnosis and treatment. The purpose of our study is to find the relationship between blood flow velocity in carotid siphon and the development of ASNV in diabetic.MethodsWe reviewed 34 eyes of 17 diabetic patients who had Transcranial Color Doppler (TCD) examination with unilateral ASNV. The circulatory parameters of both eyes of each patient were compared and analyzed. In addition, 9 patients with more than 50% stenosis of extracranial internal carotid artery (ICA) and low velocity flow through TCD had been treated by carotid revascularization surgery.ResultsThe maximal velocity in systole (Vmax) of carotid siphon (SCA) was lower in the eyes with ASNV than in the eyes without ASNV (P<0.05). ASNV of all the 9 patients regressed totally and BCVA improved significantly (P<0.05). Stenosis of ICA and arm-retina time (ART) decreased significantly (P<0.01) and SCA and ophthalmic artery (OA) increased significantly (P<0.01).ConclusionsOur study showed ASNV could be a masquerade for OIS in patients with diabetic retinopathy. The decreased blood flow velocity in carotid siphon is related to the development of ASNV. Circulatory parameters screening of SCA by TCD is important to help us to evaluate the blood flow in SCA, the possibility of development of ASNV, and the prognosis of the patient. Interference such as carotid endarterectomy (CEA) or carotid artery stenting (CAS) can be performed if necessary to improve the blood flow in SCA and make ASNV regression.

Coronary Blood Flow is Reduced by Doxorubicin: a Ultrasound Microscopic Study

The use of doxorubicin (DOX), an anti‐cancer drug, in treatment for various malignancies is limited because of its cardiotoxicity; whether DOX causes vascular disorders is unknown. Ultrasound biomicroscopy (UBM) has been a valuable, non‐invasive technique in monitoring cardiac function but not commonly used in small animal vascular studies.This study aimed to 1) study the velocity of blood flow in the left coronary artery (LCA) under physiological conditions and vascular responsiveness to DOX treatment with UBM, and 2) examine the effect of an aqueous extract of TA bark (TAAqE), a cardiotonic, on the blood‐flow velocity of LCA after DOX treatment. Young adult mice were injected intrapleurally with a single dose of DOX (20 mg/kg) or saline in the presence or absence of TAAqE. Doppler UBM was performed the day before and 1 week after DOX treatment using Vevo®2100. The blood flow of LCA and left ventricle (LV) function were monitored in the parasternal short‐axis view of UBM. The peak blood‐flow velocity of LCA during cardiac diastole and systole was 909±35 and 284±13 mm/s, respectively, (n=20) without drug treatment. Abnormality of LV function could be detected in the 1st week and was increased rapidly in the 2nd week of DOX treatment. Meanwhile, the integrated blood flow of LCA was reduced about 42% (n=9) accompanied by an increase in the resistive index by 85%. Pretreatment of TAAqE offset the detrimental effects of DOX on LCA and LV function. In summary, 1) DOX caused reduction in LCA blood‐flow velocity besides cardiotoxicity, and 2) TAAqE offered some cardiovascular protective effects. In conclusion, Doppler UBM is very useful in detecting longitudinal hemodynamic changes of LCA. The DOX‐induced decrease in blood‐flow velocity of LCA could result from reduction in the blood flow and/or vasoconstriction.

Real time flow imaging in atrial fibrillation

Background Atrial fibrillation (AF) is a common cardiac arrhythmia, affecting 33.5 million patients worldwide. The most serious complication is stroke, which is generally attributed to embolism of thrombus from the left atrium (LA). Studies utilizing transesophageal echocardiography (TEE) have shown that decreased blood flow velocities in the LA are risk factors for stroke in AF. However, TEE requires esophageal intubation and cannot fully assess the complex 3D pattern of flow in the LA. In addition, a systematic analysis of the impact of beat-to-beat variations on LA flow characteristics and thus thromboembolic risk is lacking, particularly in the presence of arrhythmia. To better elucidate the role of beat-to-beat flow variations in

Abstract T MP55: Utility of 4D-MRA to Measure Blood Flow Velocity in Cerebral Major Arteries

Transcranial Doppler is widely used clinically to measure blood flow velocity (BFV) in cerebral major arteries. This method, however, has a limitation in that its successful measurement depends on the accessibility of patients’ cranial window and the technical ability of operators. We therefore developed a novel method to measure BFV in cerebral major arteries with 4D-MRA, which was less susceptible to patients and the conditions of the operators. Methods: 4D-MRA was performed with a 3T MR unit (Achieva TX; Philips Medical Systems) using arterial spin labeling methods. The blood flow through the internal carotid arteries (ICA) and the basilar artery (BA) within imaging range was visualized by using look-locker readout methods. BFV was calculated by dividing the flow distance traveled in the arteries by the time elapsed. BFV of 34 patients (non-vascular disease:11, ICA stenotic disease:6, moyamoya disease:9, and cerebral aneurysm:8) were measured using the 4D-MRA method and the 2D phase contrast method. Results: In the case of patients with non-vascular diseases, mean BFV of the right ICA, the left ICA, and the BA was 24.5±7.0, 23.3±6.9, and 17.2±5.1 cm/sec, respectively. Correlation between BFV values from the 4D-MRA method and those from the 2D phase contrast method was statistically significant (r=0.78, p&lt;0.01). In the case of patients with ICA severe stenosis (more than 90%), BFV of the stenotic ICA was decreased to 9~11cm/sec (40~50% of BFV of the contralateral ICA). In the case of patients with advanced-stage moyamoya disease, BFV of the ICA was decreased to 9~16cm/sec (30~50% of BFV of the BA). The BFV decreases were related to CBF reduction in some cases if the development of the collateral circulation was insufficient. In the patients with aneurysm, BFV of the artery proximal to aneurysm tended to be increased except for the decrease in cavernous ICA giant aneurysm. Conclusions: We could steadily obtain BFV in all patients by using the 4D-MRA method without any operational difficulties. In this preliminary study, we observed BFV decrease in ICA stenotic disease and moyamoya disease, and BFV increase in cerebral aneurysm. This novel 4D-MRA method to measure BFV may become a promising tool for pathophysiological evaluation of cerebrovascular diseases.

Cerebrovascular reactivity in patients with rheumatoid arthritis concurrent with and without hypertension

To compare cerebrovascular reactivity (CVR) in patients with rheumatoid arthritis (RA) concurrent with essential hypertension (Group 1) and in those with RA and normal blood pressure (BP) (Group 2). During the study of Groups 1 (n = 37) and 2 (n = 12), the investigators estimated the prevalence of traditional cardiovascular risk factors, performed 24-hour BP monitoring, investigated CVR by transcranial Doppler (TCD) of the middle cerebral arteries (MCA) by hyperoxic and hypercapnic tests, and endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation of the brachial artery. The groups were matched for gender, age, RA activity and stage, and antirheumatic therapy volume. According to the results of MCA TCD, the hyperoxic test recorded impaired CVR in 34 (92%) and 10 (83%) patients in Group 1 and 2, respectively; the hypercapnic test revealed this condition in 19 (51%) and 6 (50%) patients in these groups, respectively. The hyperoxic test most commonly showed an insufficient decrease in MCA linear blood flow velocities (LBFV) in 31 (84%) and 8 (66%) patients in Groups 1 and 2, respectively; the hypercapnic test did an excessive increase in MCA LBFV in 12 (32%) and 4 (33%) patients, respectively. There was a high rate of impaired EDV in 32 (86%) and 9 (75%) patients in Groups 1 and 2, respectively. According to the results of MCA TCD, there were high and similar rates of impaired CVR in patients with RA concurrent with and without essential hypertension during the hyperoxic and hypercapnic tests.

Abstract 13383: Atrial Fibrillation Alters Both Left and Right Atrial 3D Hemodynamics

Introduction: In patients with atrial fibrillation, pulmonary embolism and right atrial (RA) thrombus are less common than stroke and left atrial (LA) thrombus. Prior studies have linked thrombus formation to decreased blood flow velocity (stasis) promoting blood clotting. We hypothesized LA stasis is more evident than RA stasis. Methods: Whole heart 4D flow MRI was performed in n=70 subjects: 33 AF patients in sinus rhythm (SR) during imaging (AF-SR, age = 62±10 years), 29 AF patients in AF (AF-afib, age = 67±12 years), and 8 age-matched controls (age = 59±5 years). 3D segmentation (MIMICS, Materialise, USA) of the LA and RA geometry was performed to calculate the flow velocity distribution for all atrial voxels and cardiac time frames. Velocity histograms normalized by the total number of entries (figure 1A) were used to assess mean and median atrial velocities and the % of LA and RA with velocities &lt;0.2m/s (stasis). Results: Compared to controls (LA = 0.20±0.2m/s, RA = 0.19±0.02m/s), both LA and RA velocities were significantly reduced in AF-SR (LA = 0.16±0.03m/s, RA = 0.16±0.04m/s, p&lt;0.03) and even further in AF-afib patients (LA = 0.13±0.03m/s, RA = 0.13±0.04m/s, p&lt;0.001). Atrial stasis was more pronounced in AF-afib (LA = 82±13%, RA = 80±16%, p&lt;0.001) and AF-SR (LA = 72±15%, RA = 69±20%, p&lt;0.04) than in controls (LA = 53±10%, RA = 53±13%). No significant RA vs LA differences were noted, Figure 1 shows significant associations (p&lt;0.01) between LA and RA mean velocity (R2=0.40) and stasis (R2=0.36) in figure 1B. RA/LA mean velocity ratio (1.0±0.2, range=0.6-2.0) and RA/LA stasis ratio (1.0±0.3, range=0.3-2.2) were not significantly different. Conclusions: In both controls and AF patients, there was no evidence for increased stasis in the LA vs RA. Although stasis likely contributes to clot formation, other factors such as atrial geometry in combination with individual LA vs. RA flow differences may account for the more prevalent formations in the LA vs. the RA.

Особливості екстракраніальної гемодинаміки хворих на бронхіальну астму дітей

У статті проаналізовано показники екстракраніальної гемодинаміки — об’ємна та лінійна швидкості кровотоку, стан периферичного судинного опору та реактивності судин при ультразвуковому допплерографічному дослідженні внутрішніх сонних та хребтових артерій 66 хворих на бронхіальну астму дітей та 22 здорових дітей. Доведено розвиток регіонарної гіпоперфузії у вертебробазилярній зоні, порушення з боку каротидних басейнів, але ці зміни не призвели до зниження об’ємної швидкості кровотоку по обох внутрішніх сонних артеріях та загального об’ємного мозкового кровотоку, що свідчить про компенсацію гемодинамічних порушень за рахунок впливу незмінних показників об’ємної швидкості в каротидних басейнах. Зміни показників екстракраніальної гемодинаміки у хворих на бронхіальну астму дітей повинні розглядатись як предиктор виникнення цереброваскулярних ускладнень у даного контингенту хворих.