Search results for "Circulation"
showing 10 items of 1137 documents
Categorizing the Role of Respiration in Cardiovascular and Cerebrovascular Variability Interactions
2022
Objective: Respiration disturbs cardiovascular and cerebrovascular controls but its role is not fully elucidated. Methods: Respiration can be classified as a confounder if its observation reduces the strength of the causal relationship from source to target. Respiration is a suppressor if the opposite situation holds. We prove that a confounding/suppression (C/S) test can be accomplished by evaluating the sign of net redundancy/synergy balance in the predictability framework based on multivariate autoregressive modelling. In addition, we suggest that, under the hypothesis of Gaussian processes, the C/S test can be given in the transfer entropy decomposition framework as well. Experimental p…
Hemodynamic Effects of Nonionic Contrast Bolus Injection and Oxygen Inhalation During Pulmonary Angiography in Patients With Chronic Major-Vessel Thr…
1996
Background Pulmonary angiography is the gold standard for the diagnosis of chronic thromboembolic pulmonary hypertension; however, major complications have been reported. This study evaluates the hemodynamic effects of direct pulmonary nonionic contrast bolus injection and oxygen inhalation in patients with chronic thromboembolic pulmonary hypertension. Methods and Results In 33 patients, hemodynamic parameters were measured after oxygen inhalation and during bolus injection of nonionic contrast medium in a control group (group 1, n=11), in a group of patients with moderately severe pulmonary hypertension (group 2, n=9), and in a group with severe pulmonary hypertension (group 3, n=13). Ox…
Cardiac surgery outcomes in patients with coronavirus disease 2019 (COVID-19): A case-series report
2020
Abstract Objective The impact of coronavirus disease 2019 (COVID-19) on the postoperative course of patients after cardiac surgery is unknown. We experienced a major severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in our cardiac surgery unit, with several patients who tested positive early after surgery. Here we describe the characteristics, postoperative course, and laboratory findings of these patients, along with the fate of the health care workers. We also discuss how we reorganize and reallocate hospital resources to resume the surgical activity without further positive patients. Methods After diagnosis of the first symptomatic patient, surgery was suspended. Naso…
Improvement of tricuspid regurgitation after pulmonary thromboendarterectomy
2002
For patients with chronic thromboembolic pulmonary hypertension who undergo pulmonary thromboendarterectomy (PTE) it has not yet been systematically investigated how operation affects the severity of tricuspid regurgitation (TR). This study sought (1) to evaluate the extent of TR reversibility after operation, (2) to identify potential predictors of the reversibility of TR, and (3) to investigate the influence of geometric and hemodynamic alterations on the extent of TR severity.Thirty-nine patients (55+/-12 years) undergoing PTE without tricuspid valve repair were investigated before and 13+/-8 days after operation by Doppler color flow mapping. Geometry of the tricuspid valve as well as r…
Human dopamine receptor D2/D3 availability predicts amygdala reactivity to unpleasant stimuli
2009
r r Abstract: Dopamine (DA) modulates the response of the amygdala. However, the relation between dopa- minergic neurotransmission in striatal and extrastriatal brain regions and amygdala reactivity to affective stimuli has not yet been established. To address this issue, we measured DA D2/D3 receptor (DRD2/3) availability in twenty-eight healthy men (nicotine-dependent smokers and never-smokers) using positron emission tomography with ( 18 F)fallypride. In the same group of participants, amygdala response to unpleasant visual stimuli was determined using blood oxygen level-dependent (BOLD) functional mag- netic resonance imaging. The effects of DRD2/3 availability in emotion-related brain …
TC perfusionale nell'ischemia cerebrale acuta: Valore predittivo dei parametri di perfusione cerebrale nel discriminare il tessuto vitale da quello i…
2007
Purpose. The aim of this study was to assess the value of computed tomography (CT) perfusion parameters in differentiating tissue viability in acute stoke patients. Materials and methods. Thirteen patients (mean age 63.3 years) with nonhaemorrhagic stroke underwent multidetector perfusion CT within 3 h of symptom onset. Images were continuously acquired at the basal ganglia over 40 s during injection of 90 ml of iodinated contrast medium injected at a rate of 9 ml/s with a 9-s delay. Z-axis coverage was 20 mm. All patients underwent diffusion-weighted magnetic resonance imaging (DWI) within 12 h of perfusion CT to define the extent of the infarct. Perfusion CT data were analysed in regions …
The DD genotype of the angiotensin converting enzyme gene independently associates with CMR-derived abnormal microvascular perfusion in patients with…
2009
Abstract Introduction The role of the angiotensin converting enzyme (ACE) gene on the result of thrombolysis at the microvascular level has not been addressed so far. We analyzed the implications of the insertion/deletion (I/D) polymorphism of the ACE gene on the presence of abnormal cardiovascular magnetic resonance (CMR)-derived microvascular perfusion after ST-segment elevation myocardial infarction (STEMI). Materials and Methods We studied 105 patients with a first anterior STEMI treated with thrombolytic agents and an open left anterior descending artery. Microvascular perfusion was assessed using first-pass perfusion CMR at 7 ±1 days. CMR studies were repeated 184 ± 11 days after STEM…
S-Ketamine-Induced NMDA Receptor Blockade during Natural Speech Production and Its Implications for Formal Thought Disorder in Schizophrenia: A Pharm…
2017
Structural and functional changes in the lateral temporal language areas have been related to formal thought disorder (FTD) in schizophrenia. Continuous, natural speech production activates the right lateral temporal lobe in schizophrenia, as opposed to the left in healthy subjects. Positive and negative FTD can be elicited in healthy subjects by glutamatergic NMDA blockade with ketamine. It is unclear whether the glutamate system is related to the reversed hemispheric lateralization during speaking in patients. In a double-blind, crossover, placebo-controlled study, 15 healthy, male, right-handed volunteers overtly described 7 pictures for 3 min each while BOLD signal changes were acquired…
FAIR and dynamic susceptibility contrast-enhanced perfusion imaging in healthy subjects and stroke patients.
2002
Purpose To compare dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) and the flow-sensitive alternating inversion recovery (FAIR) technique for measuring brain perfusion. Materials and Methods We investigated 12 patients with acute stroke, and 10 healthy volunteers with FAIR and DSC maps of regional cerebral blood volume (rCBV), mean transit time (MTT), and regional cerebral blood flow (rCBF). Results In volunteers good gray/white-matter contrast was observed in FAIR, rCBF, and rCBV maps. Regions with high signal intensities in FAIR matched well with high values of rCBV and rCBF. In ischemic stroke patients a high correlation (r = 0.78) of the ipsi- to contralate…
Effect of intraarterial papaverine or nimodipine on vessel diameter in patients with cerebral vasospasm after subarachnoid hemorrhage.
2012
Papaverine (P) and nimodipine (N) are the most widely used vasodilators when angiographic and symptomatic vasospasm is present after subarachnoid aneurysmatic hemorrhage (SAH). Their effect is only short-lived and no direct comparisons have been undertaken to evaluate the action of both substances directly. We retrospectively assessed the effect of either P or N on angiographic diameter reduction and capillary blood flow.Fifteen SAH patients with secured aneurysms and cerebral vasospasm received intraarterial P, fifteen similar patients received N. As the primary endpoint, pre- and post-infusion arterial diameters and capillary blood flow were rated retrospectively on angiographies and comp…