Search results for "HEMODYNAMICS"
showing 10 items of 511 documents
Computational Fluid-Dynamic Analysis after Carotid Endarterectomy: Patch Graft versus Direct Suture Closure.
2017
Background Closure technique after carotid endarterectomy (CEA) still remains an issue of debate. Routine use of patch graft (PG) has been advocated to reduce restenosis, stroke, and death, but its protective effect, particularly from late restenosis, is less evident and recent studies call into question this thesis. This study aims to compare PG and direct suture (DS) by means of computational fluid dynamics (CFD). To identify carotid regions with flow recirculation more prone to restenosis development, we analyzed time-averaged oscillatory shear index (OSI) and relative residence time (RRT), that are well-known indices correlated with plaque formation. Methods CFD was performed in 12 pati…
C1-esterase inhibitor reduces infarct volume after cortical vein occlusion.
1999
In order to clarify the role of complement as a mediator of cerebral infarct growth, we inhibited the classical complement activation pathway in a photochemical cortical vein occlusion model. Immediately after occlusion, rats were infused with either 0.9% saline (vehicle), or C1-esterase inhibitor (C1-INH) over 30 min. Regional cerebral blood flow (rCBF) decreased after occlusion, and was about 50% of baseline after 2 h. No difference was noted between experimental groups. Mean arterial blood pressure (MABP) and arterial blood gases were likewise unaffected by the treatment. However, administration of C1-INH had significantly reduced infarct volume by 72%, as evaluated after 5 days survival…
Exercise stress CMR reveals reduced aortic distensibility and impaired right-ventricular adaptation to exercise in patients with repaired tetralogy o…
2018
International audience; The aim of our study was to evaluate the feasibility of exercise cardiac magnetic resonance (CMR) in patients with repaired tetralogy of Fallot (RTOF) and to assess right and left ventricular adaptation and aortic wall response to exercise in comparison with volunteers.Methods11 RTOF and 11 volunteers underwent prospective CMR at rest and during exercise. A supine bicycle ergometer was employed to reach twice the resting heart rate during continuous exercise, blood pressure and heart rate were recorded. Bi-ventricular parameters and aortic stiffness were assessed using accelerated cine sequences and flow-encoding CMR. A t-test was used to compare values between group…
Prolonged Cerebral Circulation Time Is the Best Parameter for Predicting Vasospasm during Initial CT Perfusion in Subarachnoid Hemorrhagic Patients
2016
Purpose We sought to imitate angiographic cerebral circulation time (CCT) and create a similar index from baseline CT perfusion (CTP) to better predict vasospasm in patients with subarachnoid hemorrhage (SAH). Methods Forty-one SAH patients with available DSA and CTP were retrospectively included. The vasospasm group was comprised of patients with deterioration in conscious functioning and newly developed luminal narrowing; remaining cases were classified as the control group. The angiography CCT (XA-CCT) was defined as the difference in TTP (time to peak) between the selected arterial ROIs and the superior sagittal sinus (SSS). Four arterial ROIs were selected to generate four correspondin…
Cardiovascular responses to dynamic and static upper-body exercise in a cold environment in coronary artery disease patients
2021
Abstract Purpose Upper-body exercise performed in a cold environment may increase cardiovascular strain, which could be detrimental to patients with coronary artery disease (CAD). This study compared cardiovascular responses of CAD patients during graded upper-body dynamic and static exercise in cold and neutral environments. Methods 20 patients with stable CAD performed 30 min of progressive dynamic (light, moderate, and heavy rating of perceived exertion) and static (10, 15, 20, 25 and 30% of maximal voluntary contraction) upper body exercise in cold (− 15 °C) and neutral (+ 22 °C) environments. Heart rate (HR), blood pressure (BP) and electrocardiographic (ECG) responses were recorded an…
Effects of hypertonic/hyperoncotic treatment after rat cortical vein occlusion*
2003
Objective To examine the effects of hypertonic/hyperoncotic treatment on physiologic variables and regional cerebral blood flow and to test its neuroprotective efficiency in a model of permanent venous ischemia. Design Randomized prospective study. Setting University research institute. Subjects Adult male Wistar rats, weighing 359 +/- 54 g (n = 38). Interventions Rats were subjected to photochemical occlusion of two adjacent cortical veins. A randomized infusion with vehicle (0.9% NaCl), 10% hydroxyethyl starch 200,000 (HES), or 7.5% saline plus 10% hydroxyethyl starch 200,000 (HHES) was started 30 mins after two-vein occlusion. Effects on physiologic variables and regional cerebral blood …
Bridge to Operation with the GPIIb/IIIa Inhibitor Abciximab in High-Risk Coronary Patients
2006
BACKGROUND Glycoprotein-IIb/IIIa inhibitors are now frequently used in the cardiological treatment of high-risk coronary patients even if the patient is considered suitable for surgical intervention. However, there is no consensus whether GPIIb/IIIa inhibitors should be stopped before operation because of an increased risk of bleeding or if surgery should even be delayed until the anticoagulating effect subsides. METHODS From June 2002 to August 2003 140 patients who had to undergo primary aorto-coronary bypass for ongoing myocardial ischemia were enrolled in the present study. The patients received either clopidogrel, aspirin and heparin or additionally abciximab until operation. RESULTS A…
Effect of Haemodynamic Changes on Epithelium-related Intestinal Injury in Off-pump Coronary Surgery
2014
Intestinal injury is thought to play a central role in the occurrence of multiorgan dysfunction after on-pump coronary surgery. Clinical benefits of off-pump revascularisation remain, however, controversial.Hepatic enzymes and plasmatic IL-6, IL-8 and intestinal-type fatty acid binding protein (I-FABP) were determined in 20 patients (age 65-75) undergoing either on-pump (n = 10) or off-pump (n = 10) coronary surgery. Haemodynamic and biochemical parameters, catecholamine and volume therapy were monitored.Central venous pressure (CVP) was significantly higher in the off-pump group during and 12h after operation (9.5 ± 1.35 vs. 6.21 ± 0.63 mmH2O, p = 0.012). Higher GGT and GLDH levels occurre…
Shear stress alterations in the celiac trunk of patients with a continuous-flow left ventricular assist device as shown by in-silico and in-vitro flo…
2017
Background The use of left ventricular assist devices (LVADs) to treat advanced cardiac heart failure is constantly increasing, although this device leads to high risk for gastrointestinal bleeding. Methods Using in-silico flow analysis, we quantified hemodynamic alterations due to continuous-flow LVAD (HeartWare, Inc., Framingham, MA) in the celiac trunk and major branches of the abdominal aorta, and then explored the relationship between wall shear stress (WSS) and celiac trunk orientation. To assess outflow from the aortic branch, a 3-dimensional-printed patient-specific model of the celiac trunk reconstructed from an LVAD-supported patient was used to estimate echocardiographic outflow …
Diagnosis of perioperative myocardial necrosis following coronary artery surgery — a reappraisal of isoenzyme analysis
1990
Although the routine determination of CK-MB activity is widely used after coronary artery bypass grafting (CABG), the diagnosis of a perioperative myocardial necrosis remains arbitrary. The intention of the present study was to develop discriminative enzymatic parameters of CK-MB activity in a collective of 710 patients following CABG. Patients were grouped according to their postoperative electrocardiogram (ECG). For each patient, the time activity curve of CK-MB was determined. The total amount of CK-MB was calculated by integrating the area beneath the CK-MB activity curve. Patients presenting with an unchanged postoperative ECG (group I) or a new bundle branch block with uncompromised h…