950 resultados para Partial occlusion
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Delayed occlusion time in parent artery occlusion of brain-supplying vessels might carry risk for thromboembolic complications. Vascular plug devices are successfully used in cardiopulmonary and peripheral interventions to occlude high-flow lesions and have been adapted for use in neurointerventions. The purpose of the present study was to experimentally evaluate the immediate occlusion time of the AMPLATZER vascular plug (AVP) II-a second-generation cylindrical, self-expandable, resheathable nitinol wire mesh consisting of three lobes-in the carotid artery.
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Randomized trials suggested a different benefit of intravenous thrombolysis (IVT) and intra-arterial thrombolysis (IAT) between men and women with anterior circulation stroke because of a worse outcome of women in the control group.
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BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detected Pao(2). We investigated this approach by numerical simulations and applied it to quantify local Va/Q in the perfluorocarbons during partial liquid ventilation. METHODS: Numerical simulations were performed to analyze the sensitivity of the Va/Q calculation and to compare this approach with another one proposed by Rizi et al. in 2004 (Magn Reson Med 2004;52:65-72). Experimentally, the method was used during partial liquid ventilation in 7 anesthetized pigs. The Pao(2) distribution in intraalveolar perflubron was measured by fluorine-19 MRI. Respiratory gas fractions together with arterial and mixed venous blood samples were taken to quantify oxygen partial pressure and content. Using the Fick principle, the local Va/Q was estimated. The impact of gravity (nondependent versus dependent) of perflubron dose (10 vs 20 mL/kg body weight) and of inspired oxygen fraction (Fio(2)) (0.4-1.0) on Va/Q was examined. RESULTS: In numerical simulations, the Fick principle proved to be appropriate over the Va/Q range from 0.02 to 2.5. Va/Q values were in acceptable agreement with the method published by Rizi et al. In the experimental setting, low mean Va/Q values were found in perflubron (confidence interval [CI] 0.08-0.29 with 20 mL/kg perflubron). At this dose, Va/Q in the nondependent lung was higher (CI 0.18-0.39) than in the dependent lung regions (CI 0.06-0.16; P = 0.006; Student t test). Differences depending on Fio(2) or perflubron dose were, however, small. CONCLUSION: The results show that derivation of Va/Q from local Po(2) measurements using fMRI in perflubron is feasible. The low detected Va/Q suggests that oxygen transport into the perflubron-filled alveolar space is significantly restrained.
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Diagnostic coronary balloon occlusion (CBO) is mandatory for collateral function assessment, during angioscopy and optical coherence imaging, and when using certain coronary protection devices against emboli. Thus far, the safety of diagnostic CBO regarding procedural and long-term complications in normal coronary arteries has not been studied. In 316 patients, diagnostic CBO was performed for collateral function measurement in 426 angiographically normal vessels. The angioplasty balloon was inflated for 60 to 120 seconds using inflation pressures of 1 to 3 atm, followed by control angiography during and after CBO. Patients were divided into groups with entirely normal (n = 133) and partially normal (n = 183) vessels. Primary end points were procedural and long-term complications. De novo stenosis development was assessed by quantitative coronary angiography in 35% of the patients. Secondary end points were cardiac events at 5 years of follow-up. Procedural complications occurred in 1 patient (0.2%). In 150 repeat angiographic procedures in 92 patients (follow-up duration 10 +/- 15 months), quantitative coronary angiography revealed no difference in percentage diameter narrowing between baseline and follow-up (4.1% vs 3.9%, p = 0.69). During follow-up periods of 14 and 72 months, respectively, a new stenotic lesion was detected in 1 patient in each group (1.3%). Major cardiac events and percutaneous coronary intervention for stable angina were less frequent in the group with entirely normal than with partially normal vessels (0.8% vs 5.5%, p = 0.02, and 0.8% vs 18%, p <0.0001). In conclusion, low-inflation pressure diagnostic CBO in angiographically normal coronary arteries bears a minimal risk for procedural and long-term complications and can therefore be regarded as a safe procedure.
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Many people with acute myocardial infarction die from sudden cardiac arrest before reaching the hospital. The current clinical understanding of the mechanisms and risk factors surrounding sudden cardiac death is limited. However, 2 factors related to sudden death, namely the occluded coronary vessel (right coronary, left circumflex, or left anterior descending artery) and the extent of collateral circulation, are of potential relevance. Recent data suggest that the risk differs between the different coronary arteries and that coronary collateral circulation seems to have an important protective 'antiarrhythmic' effect. This editorial will address possible mechanisms and potential implications in clinical practice.
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A 36-year-old patient suffered from repeated exsudative pleural effusions and renal insufficiency (serum creatinine 1.9 mg/dl) combined with glomerular erythrocyturia, proteinuria and renal hypertension.
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The European PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) study was performed to determine the safety and efficacy of left atrial appendage occlusion by catheter technique. Embolic stroke due to atrial fibrillation is a common observation, especially in the elderly. Most thrombi in atrial fibrillation form in the left atrial appendage (LAA), its occlusion may therefore reduce the incidence of stroke in these patients.
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Intra-arterial thrombolysis can be used for treatment of basilar artery occlusion. Predictors of outcome before initiation of treatment are of special interest.
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The use of self-expanding retrievable stents is an emerging and promising treatment strategy for acute stroke treatment. The concept combines the advantages of stent deployment with immediate flow-restoration and of mechanical thrombectomy with definitive thrombus removal. The present study was performed to gain more knowledge about the principle of combined flow restoration and thrombectomy in an established animal model using radiopaque thrombi evaluating efficiency, thrombus-device interaction and possible complications of the first dedicated flow-restoration and mechanical thrombectomy device.
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Animal studies suggest that ginger (Zingiber officinale Roscoe) reduces anxiety. In this study, bioactivity-guided fractionation of a ginger extract identified nine compounds that interact with the human serotonin 5-HT(1A) receptor with significant to moderate binding affinities (K(i)=3-20 microM). [(35)S]-GTP gamma S assays indicated that 10-shogaol, 1-dehydro-6-gingerdione, and particularly the whole lipophilic ginger extract (K(i)=11.6 microg/ml) partially activate the 5-HT(1A) receptor (20-60% of maximal activation). In addition, the intestinal absorption of gingerols and shogaols was simulated and their interactions with P-glycoprotein were measured, suggesting a favourable pharmacokinetic profile for the 5-HT(1A) active compounds.
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To date, there is limited data on intra-arterial thrombolysis (IAT) and intravenous thrombolysis (IVT) for isolated posterior cerebral artery (PCA) occlusion. We aimed to evaluate recanalization, outcome and quality of life in patients who undergo thrombolysis for isolated PCA occlusion.
Knowing the future: partial foreknowledge effects on the programming of prosaccades and antisaccades
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Foreknowledge about the demands of an upcoming trial may be exploited to optimize behavioural responses. In the current study we systematically investigated the benefits of partial foreknowledge--that is, when some but not all aspects of a future trial are known in advance. For this we used an ocular motor paradigm with horizontal prosaccades and antisaccades. Predictable sequences were used to create three partial foreknowledge conditions: one with foreknowledge about the stimulus location only, one with foreknowledge about the task set only, and one with foreknowledge about the direction of the required response only. These were contrasted with a condition of no-foreknowledge and a condition of complete foreknowledge about all three parameters. The results showed that the three types of foreknowledge affected saccadic efficiency differently. While foreknowledge about stimulus-location had no effect on efficiency, task foreknowledge had some effect and response-foreknowledge was as effective as complete foreknowledge. Foreknowledge effects on switch costs followed a similar pattern in general, but were not specific for switching of the trial attribute for which foreknowledge was available. We conclude that partial foreknowledge has a differential effect on efficiency, most consistent with preparatory activation of a motor schema in advance of the stimulus, with consequent benefits for both switched and repeated trials.
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The purpose of this study was to analyze predictive factors for best-corrected visual acuity (BCVA) after anti-VEGF treatment in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO).