Restoration Algorithm-Based Ultrasound Image in Evaluating the Effect of Dexmedetomidine on Patients with Neurological Disorder Anesthetized by Sevoflurane.

The study focused on the application value of ultrasound images processed by restoration algorithm in evaluating the effect of dexmedetomidine in preventing neurological disorder in patients undergoing sevoflurane anesthesia. 90 patients undergoing tonsillectomy anesthesia were randomly divided into normal saline group, propofol group, and dexmedetomidine group. The ultrasound images were processed by restoration algorithm, and during the postoperative recovery period, ultrasound images were used to evaluate. The results showed that the original ultrasonic image was fuzzy and contained interference noise, and that the image optimized by restoration algorithm was clear, without excess noise, and the image quality was significantly improved. In the dexmedetomidine group, the extubation time was 10.6 ± 2.3 minutes, the recovery time was 8.4 ± 2.2 minutes, the average pain score during the recovery period was 2.6 ± 0.7, and the average agitation score was 7.2 ± 2.4. Of 30 patients, there were 13 cases with vertigo and 1 case with nausea and vomiting. The vascular ultrasound imaging showed that, in the dexmedetomidine group, the peak systolic velocities (PSV) of the bilateral vertebral arteries during the recovery period were 67.7 ± 14.3 and 67.9 ± 15.2 cm/s, respectively; the end-diastolic velocities (EDV) of the bilateral vertebral arteries were 27.8 ± 6.7 and 24.69 ± 5.9 cm/s, respectively; the PSV in bilateral internal carotid artery systolic peak velocities were 67.2 ± 13.9 and 67.8 ± 12.7 cm/s, respectively; the EDV in bilateral internal carotid arteries were 27.7 ± 5.3 and 26.9 ± 4.9 cm/s, respectively; bilateral vertebral artery resistance indexes (RIs) were 0.6 ± 0.02 and 0.71 ± 0.08, respectively; the bilateral internal carotid artery RIs were 0.57 ± 0.04 and 0.58 ± 0.06, respectively, all better than the normal saline group (12.1 ± 2.5 minutes, 10.1 ± 2.3 minutes, 3.9 ± 0.6, 10.6 ± 3.7, 15 cases, 11 cases, 81.5 ± 13.6, 80.7 ± 11.6 cm/s, 29.3 ± 6.8, 28.9 ± 6.7 cm/s, 74.3 ± 10.2, 73.9 ± 12.5 cm/s, 29.1 ± 4.3, 29 ± 4.5 cm/s, 0.84 ± 0.06, 0.83 ± 0.05, 0.8 ± 0.04, and 0.81 ± 0.05) and the propofol group (11.4 ± 2.1 minutes, 9.0 ± 2.1 minutes, 3.4 ± 0.8, 8.5 ± 2.3, 12 cases, 9 cases, 72.5 ± 12.9, 73.4 ± 11.8 cm/s, 28.6 ± 5.4, 26.5 ± 5.1 cm/s, 72.1 ± 11.4, 73.5 ± 10.6 cm/s, 28.8 ± 5.6, 27.3 ± 4.7 cm/s, 0.78 ± 0.07, 0.82 ± 0.06, 0.76 ± 0.03, and 0.78 ± 0.05), and the differences were statistically significant (P < 0.05). In conclusion, ultrasound images processed by restoration algorithm have high image quality and high resolution. The dexmedetomidine can prevent neurological disorder in patients with sevoflurane anesthesia and is suggested in postoperative rehabilitation.

Parasympathetic brainstem origin sites of triggered external and internal carotid vasodilation are not distributed topographically in the rat.

Cranial parasympathetic activation produces vasodilation in the head and neck region, but little is known about its central and peripheral mechanisms. This study was conducted to examine whether external and internal carotid-vasodilation origin sites triggered by chemical stimulation are distributed topographically in the parasympathetic brainstems of anesthetized rats, and to examine the effects of peripheral receptors on vasodilation. Microinjection of the neuromodulator candidate l-cysteine revealed that external and internal carotid vasodilation-triggering sites were distributed non-topographically along the full extent of the parasympathetic parvocellular reticular formation (PcRt). Intravenous injection of a muscarinic blocker and a nitric oxide synthase inhibitor abolished external carotid vasodilation, suggesting the peripheral involvement of muscarinic and nitric oxide receptors. Further work is needed to fully understand the PcRt mechanisms underlying timely and appropriate vasodilation to support various cranial functions.

Angiographic investigation of orbital vascular variations in the rabbit and implications for endovascular intra-arterial chemotherapy models.

BACKGROUND: The New Zealand White rabbit (NZWR) is the first small-animal experimental model of intra-arterial chemotherapy (IAC) for retinoblastoma treatment. The NZWR has dual ophthalmic arteries (OA): the external OA (EOA) arises from the external carotid artery and the internal OA (IOA) from the internal carotid artery. We describe the technique that we have refined for OA catheterization in rabbits, and describe the angioanatomical variations in the OA supply to the NZWR eye and implications for IAC delivery, which were identified as part of a larger project exploring IAC effects in a rabbit retinoblastoma model. METHODS: We developed techniques to perform angiography of the external and internal carotid arteries and superselective angiography of the EOA and IOA in NZWR using transfemoral access and a microwire/microcatheter system. EOA and IOA supply to the eye was determined angiographically and recorded before selective OA catheterization and angiography. RESULTS: 114 rabbits underwent carotid angiographic evaluation and OA catheterization (161 total eyes evaluated, 112 right, 49 left). Most eyes had a single dominant arterial supply; either IOA or EOA. EOA was dominant in 73% (118/161), and IOA was dominant in 17% (27/161). Co-dominant supply was seen in 10% (16/161). Of the rabbits with bilateral OA catheterization, 25/47 (53%) had bilateral dominant EOA. CONCLUSION: Successful catheterization of the OA in the NZWR can be readily accomplished with nuanced technique. The external OA is the dominant arterial supply in the majority of NZWR eyes. These findings allow for successful reproduction of OA catheterization studies of IAC for retinoblastoma in NZWR.

Kinking of Bilateral Internal Carotid Arteries as Cause of Cognitive Dysfunction.

INTRODUCTION: Dolichoarteriopathies of the internal carotid artery (DICAs) is divided into three forms: tortuous, coiling and kinking. In case of kinking, internal carotid artery forms a sharp angle of <90 degrees, while in the background there is metaplasia of a tunica media with unknown etiology. The association with stroke is still questionable, but it is believed that it can be associated with cerebral ischemia and with clinical symptomatology that accompanies cerebral ischemia. AIM: Aim of article was to present diagnostic and therapeutic modality of patient with verified internal carotid artery kinking. CASE REPORT: The 55-year-old male patient was admitted to the Department of Neurology, General Hospital «Prim.dr. Abdulah Nakas¼, due to dizziness and instability while walking, forgetfulness, memory loss and low mood. He has previously been reported to be hypertensive and with diagnosis of diabetes mellitus and dyslipidemia. Doppler sonography also suspects on distal subocclusion of the internal carotid artery (low flow rates were observed). Diagnostic transcranial Doppler (TCD) of vertebrobasilar artery showed decreased blood flow velocities in both vertebral and basilar artery and indicated atherosclerotic altered blood vessels of the brain. CTA findings indicate bilateral kinking of internal carotid artery with right duplex Kinking. SPECT with 15 mCi 99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO) verified global cortex hypoperfusion, indicating chronic vascular failure. The patient was treated with acetylsalic acid, clopidogrel, atorvastatin, donepezil, memantine, escitalopram, bromazepam, along with antihypertensive and antidiabetic therapy (per os). CONCLUSION: A severe degree of kinking can cause neurological symptomatology, especially if it is bilateral. Symptoms of cerebrovascular disease are more pronounced when autoregulation of cerebral hemodynamics is impaired. Bilateral severe degree of kinking possibly can cause cognitive impairment. Diagnosis, analysis of the existence of possible risk factors for the onset, and the existence of genetic predisposition are a prerequisite for better understanding of the disease and optimal treatment.

Aspirin Monotherapy in Flow Diversion of Selected Internal Carotid Artery Aneurysms.

BACKGROUND: Dual antiplatelet therapy has been adopted as the standard of care for intracranial stenting, including flow diversion of cerebral aneurysms, to reduce the risk of acute and delayed ischemic complications. CASE DESCRIPTION: This is a report of 2 cases in which patients who underwent flow diversion of unruptured internal carotid artery aneurysms were treated with aspirin monotherapy. Neither patient tolerated dual antiplatelet therapy, one because of nosebleeds due to hereditary hemorrhagic telangiectasia and one because of an unnamed bleeding disorder. The lesions-a previously coiled, recanalizing dorsal internal carotid artery aneurysm and a small superior hypophyseal aneurysm-were each treated with a single Pipeline Flex embolization device and were completely occluded with normal-appearing parent vessel on 12-month follow-up digital subtraction angiography. CONCLUSIONS: This is the first report of patients electively treated with flow diversion using Pipeline Flex embolization device on aspirin monotherapy in the literature.

Granulomatous hypophysitis causing compression of the internal carotid arteries reversible with azathioprine and rituximab treatment.

INTRODUCTION: Compression of the internal carotid artery (ICA) in the cavernous sinus area is a rare event and is mostly associated with pituitary adenomas and meningiomas. Other causes of ICA compression are less well known. We present a rare case of granulomatous hypophysitis causing compression of the ICA, which was treated successfully with immune-suppressive agents. METHODS: The electronic database MEDLINE (PubMed) was searched systematically and other cases with ICA compression were identified and analyzed. RESULTS: A female patient with a history of two previous transsphenoidal operations for suspected pituitary adenoma and post-operative complete pituitary insufficiency presented with severe headaches, nausea, fatigue, and diplopia. Pituitary MRI scan suggested relapse of the pituitary lesion with atypical bilateral infiltration of cavernous sinuses and compression of ICAs. After histological reevaluation of her previous pituitary operations, granulomatous hypophysitis was diagnosed. Treatment was started with high doses of prednisolone. With decreasing doses of prednisolone, symptoms recurred, and azathioprine was started, followed by administration of rituximab resulting in clinical recovery and regression of ICA compression. Literature analysis disclosed 36 case reports with ICA compression in the cavernous sinus region (12 pituitary adenoma, 6 meningioma, 7 hypophysitis, 5 other tumors, and 4 other etiologies). Two cases of hypophysitis recovered completely; five cases improved only partly. CONCLUSION: In the case of ICA compression, clinical signs, onset of symptoms, radiological findings and pituitary insufficiencies should be thoroughly evaluated, and hypophysitis should be considered as a possible cause. In our patient, treatment with azathioprine and, finally, rituximab was successful.

Internal Carotid Artery Blood Flow Response to Anesthesia, Pneumoperitoneum, and Head-up Tilt during Laparoscopic Cholecystectomy.

BACKGROUND: Little is known about how implementation of pneumoperitoneum and head-up tilt position contributes to general anesthesia-induced decrease in cerebral blood flow in humans. We investigated this question in patients undergoing laparoscopic cholecystectomy, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion. METHODS: In a nonrandomized, observational study of 16 patients (American Society of Anesthesiologists physical status I or II) undergoing laparoscopic cholecystectomy, internal carotid artery blood velocity was measured by Doppler ultrasound at four time points: awake, after anesthesia induction, after induction of pneumoperitoneum, and after head-up tilt. Vessel diameter was obtained each time, and internal carotid artery blood flow, the main outcome variable, was calculated. The authors recorded pulse contour estimated mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV) index, cardiac index, end-tidal carbon dioxide (ETCO2), bispectral index, and ventilator settings. Results are medians (95% CI). RESULTS: Internal carotid artery blood flow decreased upon anesthesia induction from 350 ml/min (273 to 410) to 213 ml/min (175 to 249; -37%, P < 0.001), and tended to decrease further with pneumoperitoneum (178 ml/min [127 to 208], -15%, P = 0.026). Tilt induced no further change (171 ml/min [134 to 205]). ETCO2 and bispectral index were unchanged after induction. MAP decreased with anesthesia, from 102 (91 to 108) to 72 (65 to 76) mmHg, and then remained unchanged (Pneumoperitoneum: 70 [63 to 75]; Tilt: 74 [66 to 78]). Cardiac index decreased with anesthesia and with pneumoperitoneum (overall from 3.2 [2.7 to 3.5] to 2.3 [1.9 to 2.5] l · min · m); tilt induced no further change (2.1 [1.8 to 2.3]). Multiple regression analysis attributed the fall in internal carotid artery blood flow to reduced cardiac index (both HR and SV index contributing) and MAP (P < 0.001). Vessel diameter also declined (P < 0.01). CONCLUSIONS: During laparoscopic cholecystectomy, internal carotid artery blood flow declined with anesthesia and with pneumoperitoneum, in close association with reductions in cardiac index and MAP. Head-up tilt caused no further reduction. Cardiac output independently affects human cerebral blood flow.

Catastrophic Secondary Infarctions with Onset Seizure Following Tissue Plasminogen Activator Therapy.

Fatalities following intravenous recombinant tissue-type plasminogen activator therapy have been reported. Major fatal complications following intravenous recombinant tissue-type plasminogen activator therapy include intracranial hemorrhage, aortic dissection, and extracranial bleeding. However, the possibility that intravenous recombinant tissue-type plasminogen activator therapy itself paradoxically induces synchronized multiple cerebral novel infarctions has never been considered. We herein report the first case of bilateral internal carotid artery infarction with onset seizure following intravenous recombinant tissue-type plasminogen activator therapy for a vertebral-basilar artery infarction. A 75-year-old man was transferred to our hospital and diagnosed with acute ischemic stroke in the basilar artery. His National Institute of Health Stroke Scale score was 4. The intravenous recombinant tissue-type plasminogen activator therapy was initiated 234 minutes after stroke onset because no contraindications were present. Almost 2 hours after the intravenous recombinant tissue-type plasminogen activator therapy, the patient suddenly fell into a deep coma with generalized convulsions. A huge secondary infarction was found in the bilateral anterior circulation territories, and he died 7 days after stroke onset. This case alerts clinicians to the possibility of synchronized multiple cerebral infarctions following intravenous recombinant tissue-type plasminogen activator therapy as a dangerous complication in patients with multiple severe stenoses in the cerebral arteries.

Sodium nitroprusside dilates cerebral vessels and enhances internal carotid artery flow in young men.

KEY POINTS: Sodium nitroprusside lowers blood pressure by vasodilatation but is reported to reduce cerebral blood flow. In healthy young men sodium nitroprusside reduced blood pressure, total peripheral resistance, and arterial CO2 tension and yet cerebral blood flow was maintained, with an increase in internal carotid artery blood flow and cerebrovascular conductance. Sodium nitroprusside induces both systemic and cerebral vasodilatation affecting internal carotid artery more than vertebral artery flow. ABSTRACT: Cerebral autoregulation maintains cerebral blood flow (CBF) despite marked changes in mean arterial pressure (MAP). Sodium nitroprusside (SNP) reduces blood pressure by vasodilatation but is reported to lower CBF, probably by a reduction in its perfusion pressure. We evaluated the influence of SNP on CBF and aimed for a 20% and then 40% reduction in MAP, while keeping MAP ≥ 50 mmHg, to challenge cerebral autoregulation. In 19 healthy men (age 24 ± 4 years; mean ± SD) duplex ultrasound determined right internal carotid (ICA) and vertebral artery (VA) blood flow. The SNP reduced MAP (from 83 ± 8 to 69 ± 8 and 58 ± 4 mmHg; both P < 0.0001), total peripheral resistance, and arterial CO2 tension (P aC O2; 41 ± 3 vs. 39 ± 3 and 37 ± 4 mmHg; both P < 0.01). Yet ICA flow increased with the moderate reduction in MAP but returned to the baseline value with the large reduction in MAP (336 ± 66 vs. 365 ± 69; P = 0.013 and 349 ± 82 ml min-1 ; n.s.), while VA flow (114 ± 34 vs. 112 ± 38 and 110 ± 42 ml min-1 ; both n.s.) and CBF ((ICA + VA flow) × 2; 899 ± 135 vs. 962 ± 127 and 918 ± 197 ml min-1 ; both n.s.) were maintained with increased cerebrovascular conductance. In conclusion, CBF is maintained during SNP-induced reduction in MAP despite reduced P aC O2 and the results indicate that SNP dilates cerebral vessels and increases ICA flow.

UBC-Nepal expedition: The use of oral antioxidants does not alter cerebrovascular function at sea level or high altitude.

NEW FINDINGS: What is the central question of the study? Does the use of antioxidants alter cerebrovascular function and blood flow at sea level (344 m) and/or high altitude (5050 m)? What is the main finding and its importance? This is the first study to investigate whether antioxidant administration alters cerebrovascular regulation and blood flow in response to hypercapnia, acute hypoxia and chronic hypoxia in healthy humans. We demonstrate that an acute dose of antioxidants does not alter cerebrovascular function and blood flow at sea level (344 m) or after 12 days at high altitude (5050 m). ABSTRACT: Hypoxia is associated with an increase in systemic and cerebral formation of free radicals and associated reactants that may be linked to impaired cerebral vascular function and neurological sequelae. To what extent oral antioxidant prophylaxis impacts cerebrovascular function in humans throughout the course of acclimatization to the hypoxia of terrestrial high altitude has not been examined. Thus, the purpose of the present study was to examine the influence of orally ingested antioxidants at clinically relevant doses (vitamins C and E and α-lipoic acid) on cerebrovascular regulation at sea level (344 m; n = 12; female n = 2 participants) and at high altitude (5050 m; n = 9; female n = 2) in a randomized, placebo-controlled and double-blinded crossover design. Hypercapnic and hypoxic cerebrovascular reactivity tests of the internal carotid artery (ICA) were conducted at sea level, and global and regional cerebral blood flow (CBF; i.e. ICA and vertebral artery) were assessed 10-12 days after arrival at 5050 m. At sea level, acute administration of antioxidants did not alter cerebral hypoxic cerebrovascular reactivity (pre versus post: 1.5 ± 0.7 versus 1.2 ± 0.8%∆CBF/-%∆SpO2; P = 0.96) or cerebral hypercapnic cerebrovascular reactivity (pre versus post: 5.7 ± 2.0 versus 5.8 ± 1.9%∆CBF/∆mmHg; P = 0.33). Furthermore, global CBF (P = 0.43) and cerebral vascular conductance (ICA P = 0.08; vertebral artery P = 0.32) were unaltered at 5050 m after antioxidant administration. In conclusion, these data show that an oral antioxidant cocktail known to attenuate systemic oxidative stress failed to alter cerebrovascular function at sea level and CBF during acclimatization to high altitude.

Internal Carotid Artery Web as the Cause of Recurrent Cryptogenic Ischemic Stroke.

Carotid artery web is considered an exceptional cause of recurrent ischemic strokes in the affected arterial territory. The underlying pathology proposed for this entity is an atypical fibromuscular dysplasia. We present the case of a 43-year-old woman with no cardiovascular risk factors who had experienced 2 cryptogenic ischemic strokes in the same arterial territory within an 11-month period. Although all diagnostic tests initially yielded normal results, detailed analysis of the computed tomography angiography images revealed a carotid web; catheter angiography subsequently confirmed the diagnosis. Carotid surgery was performed, since which time the patient has remained completely asymptomatic. The histological finding of intimal hyperplasia is consistent with previously reported cases of carotid artery web. Carotid artery web is an infrequent cause of stroke, and this diagnosis requires a high level of suspicion plus a detailed analysis of vascular imaging studies.

Effect of increases in cardiac contractility on cerebral blood flow in humans.

The effect of acute increases in cardiac contractility on cerebral blood flow (CBF) remains unknown. We hypothesized that the external carotid artery (ECA) downstream vasculature modifies the direct influence of acute increases in heart rate and cardiac function on CBF regulation. Twelve healthy subjects received two infusions of dobutamine [first a low dose (5 µg·kg-1·min-1) and then a high dose (15 µg·kg-1·min-1)] for 12 min each. Cardiac output, blood flow through the internal carotid artery (ICA) and ECA, and echocardiographic measurements were performed during dobutamine infusions. Despite increases in cardiac contractility, cardiac output, and arterial pressure with dobutamine, ICA blood flow and conductance slightly decreased from resting baseline during both low- and high-dose infusions. In contrast, ECA blood flow and conductance increased appreciably during both low- and high-dose infusions. Greater ECA vascular conductance and corresponding increases in blood flow may protect overperfusion of intracranial cerebral arteries during enhanced cardiac contractility and associated increases in cardiac output and perfusion pressure. Importantly, these findings suggest that the acute increase of blood perfusion attributable to dobutamine administration does not cause cerebral overperfusion or an associated risk of cerebral vascular damage.NEW & NOTEWORTHY A dobutamine-induced increase in cardiac contractility did not increase internal carotid artery blood flow despite an increase in cardiac output and arterial blood pressure. In contrast, external carotid artery blood flow and conductance increased. This external cerebral blood flow response may assist with protecting from overperfusion of intracranial blood flow.

Endovascular Treatment of Large and Giant Carotid Aneurysms with Flow-Diverter Stents Alone or in Combination with Coils: A Multicenter Experience and Long-Term Follow-up.

BACKGROUND: Although flow diverters (FDs) have been widely accepted by neurointerventionists, their safety has yet to be fully defined. Stratification by aneurysm size and location is essential for correct evaluation of treatment outcomes and risks of flow diversion. OBJECTIVE: To compare neurological and anatomic outcomes and evaluate the risk of complications after endovascular treatment of large or giant internal carotid artery (ICA) aneurysms with FD/FDs alone or together with coil embolization. METHODS: We reviewed all patients with large or giant, ruptured or unruptured ICA aneurysms who underwent endovascular treatment with flow diversion alone (group A) or with concomitant coiling (group B) in 4 international institutions between 2010 and 2015. Anatomic outcome was evaluated using the Byrne scale on digital subtraction angiography and/or angioMRI and/or angioCT scans 3, 6, 12, and 24 months postoperatively. RESULTS: We collected 44 patients with large or giant ICA aneurysms. Four patients (9%) presented with aneurysmal subarachnoid hemorrhage (SAH). FD/FDs were used alone in 26 patients and in combination with coil embolization in the 18 remaining patients. The mortality rate due to procedure-related and/or neurological complications was 2.2%. Twelve months after the procedure, 88.6% (n = 39) of patients had a favorable neurological outcome. One year after the procedure, the aneurysm was completely occluded in 72.7% of patients: 61.5% (16/18) in group A and 88.9% (16/26) in group B. CONCLUSION: Clinical outcomes and rates of intraoperative and postoperative complications did not differ significantly between the groups. Better anatomic results using FD/FDs combined with coils were documented 6 months after the procedure; this option seems to provide a higher aneurysm occlusion rate and reduce the need for retreatment.

Comparing the Intracarotid Amobarbital Test and Functional MRI for the Presurgical Evaluation of Language in Epilepsy.

Surgery is the treatment of choice for drug-resistant temporal lobe epilepsy (TLE). However, such surgery frequently causes deficits in language function, especially if performed on the dominant hemisphere. In recent years, the intracarotid amobarbital test (IAT) has been gradually replaced by functional magnetic resonance imaging (fMRI) in the preoperative identification of language areas to estimate the risk of postoperative language decline. In this paper, we review the neural substrates for language processing, how language impairment can result both from TLE itself and from surgical attempts to treat it. Subsequently, we discuss the strengths and limitations of, and current indications for fMRI and IAT during the preoperative workup, both by discussion of the studies that have evaluated them individually and through meta-analysis of data from 31 studies deemed eligible for analysis. Electrocortical stimulation mapping (ESM) is also discussed, as is the usefulness of the novel technique of resting-state fMRI. Finally, surgical techniques designed to avoid or reduce language decline in patients at risk are explored.

Lack of linear correlation between dynamic and steady-state cerebral autoregulation.

KEY POINTS: For correct application and interpretation of cerebral autoregulation (CA) measurements in research and in clinical care, it is essential to understand differences and similarities between dynamic and steady-state CA. The present study found no correlation between dynamic and steady-state CA indices in healthy older adults. There was variability between individuals in all (steady-state and dynamic) autoregulatory indices, ranging from low (almost absent) to highly efficient CA in this healthy population. These findings challenge the assumption that assessment of a single CA parameter or a single set of parameters can be generalized to overall CA functioning. Therefore, depending on specific research purposes, the choice for either steady-state or dynamic measures or both should be weighed carefully. ABSTRACT: The present study aimed to investigate the relationship between dynamic (dCA) and steady-state cerebral autoregulation (sCA). In 28 healthy older adults, sCA was quantified by a linear regression slope of proportionate (%) changes in cerebrovascular resistance (CVR) in response to proportionate (%) changes in mean blood pressure (BP) induced by stepwise sodium nitroprusside (SNP) and phenylephrine (PhE) infusion. Cerebral blood flow (CBF) was measured at the internal carotid artery (ICA) and vertebral artery (VA) and CBF velocity at the middle cerebral artery (MCA). With CVR = BP/CBF, Slope-CVRICA , Slope-CVRVA and Slope-CVRiMCA were derived. dCA was assessed (i) in supine rest, analysed with transfer function analysis (gain and phase) and autoregulatory index (ARI) fit from spontaneous oscillations (ARIBaseline ), and (ii) with transient changes in BP using a bolus injection of SNP (ARISNP ) and PhE (ARIPhE ). Comparison of sCA and dCA parameters (using Pearson's r for continuous and Spearman's ρ for ordinal parameters) demonstrated a lack of linear correlations between sCA and dCA measures. However, comparisons of parameters within dCA and within sCA were correlated. For sCA slope-CVRVA with Slope-CVRiMCA (r = 0.45, P < 0.03); for dCA ARISNP with ARIPhE (ρ = 0.50, P = 0.03), ARIBaseline (ρ = 0.57, P = 0.03) and PhaseLF (ρ = 0.48, P = 0.03); and for GainVLF with GainLF (r = 0.51, P = 0.01). By contrast to the commonly held assumption based on an earlier study, there were no linear correlations between sCA and dCA. As an additional observation, there was strong inter-individual variability, both in dCA and sCA, in this healthy group of elderly, in a range from low to high CA efficiency.

ß1-Blockade increases maximal apnea duration in elite breath-hold divers.

We hypothesized that the cardioselective ß1-adrenoreceptor antagonist esmolol would improve maximal apnea duration in elite breath-hold divers. In elite national-level divers (n = 9), maximal apneas were performed in a randomized and counterbalanced order while receiving either iv esmolol (150 µg·kg-1·min-1) or volume-matched saline (placebo). During apnea, heart rate (ECG), beat-by-beat blood pressure, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured (finger photoplethysmography). Myocardial oxygen consumption (MV̇o2) was estimated from rate pressure product. Cerebral blood flow through the internal carotid (ICA) and vertebral arteries (VA) was assessed using Duplex ultrasound. Apnea duration improved in the esmolol trial when compared with placebo (356 ± 57 vs. 323 ± 61 s, P < 0.01) despite similar end-apnea peripheral oxyhemoglobin saturation (71.8 ± 10.3 vs. 74.9 ± 9.5%, P = 0.10). The HR response to apnea was reduced by esmolol at 10-30% of apnea duration, whereas MAP was unaffected. Esmolol reduced SV (main effect, P < 0.05) and CO (main effect; P < 0.05) and increased TPR (main effect, P < 0.05) throughout apnea. Esmolol also reduced MV̇o2 throughout apnea (main effect, P < 0.05). Cerebral blood flow through the ICA and VA was unchanged by esmolol at baseline and the last 30 s of apnea; however, global cerebral blood flow was reduced in the esmolol trial at end-apnea (P < 0.05). Our findings demonstrate that, in elite breath-hold divers, apnea breakpoint is improved by ß1-blockade, likely owing to an improved total body oxygen sparring through increased centralization of blood volume (↑TPR) and reduced MV̇o2NEW & NOTEWORTHY The governing bodies for international apnea competition, the Association Internationale pour le Développment de l'Apnée and La Confédération Mondaile des Activités Subaquatiques, have banned the use of ß-blockers based on anecdotal reports that they improve apnea duration. Using a randomized placebo-controlled trial, we are the first to empirically confirm that ß-blockade improves apnea duration. This improvement in apnea duration coincided with a reduced myocardial oxygen consumption.

[PROPHYLAXIS OF COGNITIVE DEFICIENCY WHILE PERFORMING ЕNDARTERECTOMY IN PATIENTS, SUFFERING STENOTIC AFFECTIONS OF CAROTID ARTERIES: THE ROLE OF MULTIDISCIPLINARY APPROACH].

Efficacy of the cognitive deficiency prophylaxis was studied in patients, suffering stenotic affection of carotid arteries. Application of intraoperative neuroprotection, using neoton, have permitted to reduce the reperfusion syndrome signs rate from 35.6 to 3.4%, аnd the cognitive deficiency level as well, causing the general occurrence risk of intraoperative or early morbidity lowering. It is expedient to apply the multidisciplinary approach for guaranteeing of adequate quality of clinical monitoring for cognitive functions.

[Intraluminal Thrombus in Internal Carotid Artery Successfully Treated with Adjuvant Anticoagulant Therapy Followed by Carotid Endarterectomy:A Case Report].

BACKGROUND: An intraluminal thrombus in the carotid artery is relatively rare. A high frequency of perioperative symptomatic stroke has been reported in patients undergoing carotid endarterectomy, and no standard therapy has yet been developed. CASE PRESENTATION: A 69-year-old woman, with no history of trauma, presented with ischemic stroke and mild right hemiparesis. Computed tomography and MRI showed an infarction in the left parietal region. A carotid Doppler study showed carotid stenosis on the left side. Further investigation with digital subtraction angiography confirmed significant carotid artery stenosis with an intraluminal thrombus in the left internal carotid artery. She was treated with initial intravenous anticoagulant therapy followed by carotid endarterectomy with thrombus removal 14 days after admission(subacute phase). There was no postoperative complication and she had uneventful course over 3 years of follow-up. CONCLUSION: Initial adjuvant anticoagulant therapy for symptomatic intraluminal thrombus followed by carotid revascularization is an effective surgical strategy. A meticulous surgical procedure is required to perform a carotid endarterectomy in patients with an intraluminal thrombus.

The influence of anesthesia and fluid-structure interaction on simulated shear stress patterns in the carotid bifurcation of mice.

BACKGROUND: Low and oscillatory wall shear stresses (WSS) near aortic bifurcations have been linked to the onset of atherosclerosis. In previous work, we calculated detailed WSS patterns in the carotid bifurcation of mice using a Fluid-structure interaction (FSI) approach. We subsequently fed the animals a high-fat diet and linked the results of the FSI simulations to those of atherosclerotic plaque location on a within-subject basis. However, these simulations were based on boundary conditions measured under anesthesia, while active mice might experience different hemodynamics. Moreover, the FSI technique for mouse-specific simulations is both time- and labor-intensive, and might be replaced by simpler and easier Computational Fluid Dynamics (CFD) simulations. The goal of the current work was (i) to compare WSS patterns based on anesthesia conditions to those representing active resting and exercising conditions; and (ii) to compare WSS patterns based on FSI simulations to those based on steady-state and transient CFD simulations. METHODS: For each of the 3 computational techniques (steady state CFD, transient CFD, FSI) we performed 5 simulations: 1 for anesthesia, 2 for conscious resting conditions and 2 more for conscious active conditions. The inflow, pressure and heart rate were scaled according to representative in vivo measurements obtained from literature. RESULTS: When normalized by the maximal shear stress value, shear stress patterns were similar for the 3 computational techniques. For all activity levels, steady state CFD led to an overestimation of WSS values, while FSI simulations yielded a clear increase in WSS reversal at the outer side of the sinus of the external carotid artery that was not visible in transient CFD-simulations. Furthermore, the FSI simulations in the highest locomotor activity state showed a flow recirculation zone in the external carotid artery that was not present under anesthesia. This recirculation went hand in hand with locally increased WSS reversal. CONCLUSIONS: Our data show that FSI simulations are not necessary to obtain normalized WSS patterns, but indispensable to assess the oscillatory behavior of the WSS in mice. Flow recirculation and WSS reversal at the external carotid artery may occur during high locomotor activity while they are not present under anesthesia. These phenomena might thus influence plaque formation to a larger extent than what was previously assumed.