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Background: Since hemodynamics plays a key role in the development and evolution of cardiovascular pathologies, physician's decision must be based on proper monitoring of relevant physiological flow quantities. Methods: A numerical analysis of the error introduced by an intravascular Doppler guide wire on the peak velocity measurements has been carried out. The effect of probe misalignment (±10°) with respect to the vessel axis was investigated. Numerical simulations were performed on a realistic 3D geometry, reconstructed from coronary angiography images. Furthermore, instead of using Poiseuille or Womersley approximations, the unsteady pulsatile inlet boundary condition has been calculated from experimental peak-velocity measurements inside the vessel through a new approach based on an iterative Newton's algorithm. Results: The results show that the presence of the guide modifies significantly both the maximum velocity and the peak position in the section plane; the difference is between 6 and 17 % of the maximum measured velocity depending on the distance from the probe tip and the instantaneous vessel flow rate. Furthermore, a misalignment of the probe may lead to a wrong estimation of the peak velocity with an error up to 10 % depending on the probe orientation angle. Conclusions: The Doppler probe does affect the maximum velocity and its position during intravascular Doppler measurements. Moreover, the Doppler-probe-wire sampling volume at 5.2 and 10 mm far from the probe tip is not sufficient to prevent its influence on the measurement. This should be taken into account in clinical practice by physicians during intravascular Doppler quantification. The new numerical approach used in this work could potentially be helpful in future numerical simulations to set plausible inlet boundary conditions., SCOPUS: ar.j, info:eu-repo/semantics/published

Background: To investigate the predictive value of decreased urine output based on the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal disease (RIFLE) classification on contrast- induced acute kidney injury (CA-AKI) in intensive care (ICU) patients. Methods: All patients who received contrast media (CM) injection for CT scan or coronary angiography during a 3-year period in a 24 bed medico-surgical ICU were reviewed. Results: Daily serum creatinine concentrations and diuresis were measured for 3 days after CM injection. We identified 23 cases of CA-AKI in the 149 patients included (15.4 %). Patients who developed CA-AKI were more likely to require renal replacement therapy and had higher ICU mortality rates. At least one RIFLE urine output criteria was observed in 45 patients (30.2 %) and 14 of these 45 patients (31.1 %) developed CA-AKI based on creatinine concentrations. In 30 % of these cases, urine output decreased or didn't change after the increase in creatinine concentrations. The RIFLE urine output criteria had low sensitivity (39.1 %) and specificity (67.9 %) for prediction of CA-AKI, a low positive predictive value of 50 % and a negative predictive value of 87.2 %. The maximal dose of vasopressors before CM was the only independent predictive factor for CA-AKI. Conclusions: CA-AKI is a frequent pathology observed in ICU patients and is associated with increased need for renal replacement therapy and increased mortality. The predictive value of RIFLE urine output criteria for the development of CA-AKI based on creatinine concentrations was low, which limits its use for assessing the effects of therapeutic interventions on the development and progression of AKI., SCOPUS: ar.j, info:eu-repo/semantics/published

OBJECTIVE: The MEDCOR trial is a double-blind, randomized study aiming at demonstrating the superiority of molsidomine (direct NO donor) over placebo, used as add-on treatments, on improving endothelial function (EF) after 12 months, in stable angina patients undergoing percutaneous coronary intervention. METHODS: EF was assessed by peripheral vasodilator response (i.e. Endoscore) using arterial tonometry and by several biomarkers, in terms of changes versus baseline after a one-year treatment. RESULTS: The change in Endoscore was +75 ± 130% in placebo group and +39 ± 145% in molsidomine group (p = 0.143). There was a decrease in sICAM-1 with molsidomine (-6%) and an increase with placebo (+6%). The MPO activity/antigen ratio slightly increased with placebo (+9%) and strongly decreased with molsidomine (-42%) (p = 0.020). CONCLUSION: The MEDCOR trial was not able to demonstrate significant differences between molsidomine and placebo for all parameters, except the MPO activity/antigen ratio which significantly decreased with molsidomine (p = 0.020 versus placebo). TRIAL REGISTRATION: ClinicalTrials.gov NCT01363661.

Objectives We sought to provide a systematic review of reported cases of LAA closure device embolization by focusing on the two most commonly implanted devices: the Watchman (WM) device and the Amplatzer Cardiac Plug (ACP). Methods A comprehensive search of the Pubmed database was conducted until October 1, 2014. Studies were included if they described at least 1 case of embolization of the WM and/or the ACP. Results A total of 20 studies reporting 31 cases of device embolization were identified, including 13 cases with WM and 18 cases. The timing of embolization was described in 29 cases and was categorized as acute in 20 cases (65%) and late in 9 cases (30%). The anatomical location of embolized devices was reported in 21 cases: into the aorta in 9 cases, into the left ventricle (LV) in 9 cases and into the left atrial cavity in 3 cases. As compared to embolization into the aorta or the left atrial cavity, device embolization into the LV was associated with a higher rate of surgical retrieval (8/9 vs 2/12; 88% vs 17%, P=0.0019). Major adverse events related to device embolization occurred in three patients (9.6%). Conclusions LAA closure device embolization occurs mainly in the periprocedural period but late embolizations are not uncommon. Although embolization into the aorta or the left atrium can be successfully managed by percutaneous techniques in most cases, device embolization into the LV is associated with a higher rate of surgical retrieval, increasing thereby procedure-related morbidity.

Background: It is a known fact that blood flow pattern and more specifically the pulsatile time variation of shear stress on the vascular wall play a key role in atherogenesis. The paper presents the conception, the building and the control of a new in vitro test bench that mimics the pulsatile flows behavior based on in vivo measurements. Methods: An in vitro cardiovascular simulator is alimented with in vivo constraints upstream and provided with further post-processing analysis downstream in order to mimic the pulsatile in vivo blood flow quantities. This real-time controlled system is designed to perform real pulsatile in vivo blood flow signals to study endothelial cells' behavior under near physiological environment. The system is based on an internal model controller and a proportional-integral controller that controls a linear motor with customized piston pump, two proportional-integral controllers that control the mean flow rate and temperature of the medium. This configuration enables to mimic any resulting blood flow rate patterns between 40 and 700 ml/min. In order to feed the system with reliable periodic flow quantities in vivo measurements were performed. Data from five patients (1 female, 4 males; ages 44-63) were filtered and post-processed using the Newtonian Womersley's solution. These resulting flow signals were compared with 2D axisymmetric, numerical simulation using a Carreau non-Newtonian model to validate the approximation of a Newtonian behavior. Results: This in vitro test bench reproduces the measured flow rate time evolution and the complexity of in vivo hemodynamic signals within the accuracy of the relative error below 5%. Conclusions: This post-processing method is compatible with any real complex in vivo signal and demonstrates the heterogeneity of pulsatile patterns in coronary arteries among of different patients. The comparison between analytical and numerical solution demonstrate the fair quality of the Newtonian Womersley's appr, SCOPUS: ar.j, info:eu-repo/semantics/published