- Pulmonary pulse wave transit time is associated with right ventricular-pulmonary artery coupling in pulmonary arterial hypertension. [Journal Article]
- PCPulm Circ 2016; 6(4):576-585
- Pulmonary pulse wave transit time (pPTT), defined as the time for the systolic pressure pulse wave to travel from the pulmonary valve to the pulmonary veins, has been reported to be reduced in pulmon...
Pulmonary pulse wave transit time (pPTT), defined as the time for the systolic pressure pulse wave to travel from the pulmonary valve to the pulmonary veins, has been reported to be reduced in pulmonary arterial hypertension (PAH); however, the underlying mechanism of reduced pPTT is unknown. Here, we investigate the hypothesis that abbreviated pPTT in PAH results from impaired right ventricular-pulmonary artery (RV-PA) coupling. We quantified pPTT using pulsed-wave Doppler ultrasound from 10 healthy age- and sex-matched controls and 36 patients with PAH. pPTT was reduced in patients with PAH compared with controls. Univariate analysis revealed the following significant predictors of reduced pPTT: age, right ventricular fractional area change (RV FAC), tricuspid annular plane excursion (TAPSE), pulmonary arterial pressures (PAP), diastolic pulmonary gradient, transpulmonary gradient, pulmonary vascular resistance, and RV-PA coupling (defined as RV FAC/mean PAP or TAPSE/mean PAP). Although the correlations between pPTT and invasive markers of pulmonary vascular disease were modest, RV FAC (r = 0.64, P < 0.0001), TAPSE (r = 0.67, P < 0.0001), and RV-PA coupling (RV FAC/mean PAP: r = 0.72, P < 0.0001; TAPSE/mean PAP: r = 0.74, P < 0.0001) had the strongest relationships with pPTT. On multivariable analysis, only RV FAC, TAPSE, and RV-PA coupling were independent predictors of pPTT. We conclude that shortening of pPTT in patients with PAH results from altered RV-PA coupling, probably occurring as a result of reduced pulmonary arterial compliance. Thus, pPTT allows noninvasive determination of the status of both the pulmonary vasculature and the response of the RV in patients with PAH, thereby allowing monitoring of disease progression and regression.
- Standardized echocardiographic assessment of cardiac function in normal adult zebrafish and heart disease models. [Journal Article]
- DMDis Model Mech 2017 Jan 01; 10(1):63-76
- The zebrafish (Danio rerio) is an increasingly popular model organism in cardiovascular research. Major insights into cardiac developmental processes have been gained by studies of embryonic zebrafis...
The zebrafish (Danio rerio) is an increasingly popular model organism in cardiovascular research. Major insights into cardiac developmental processes have been gained by studies of embryonic zebrafish. However, the utility of zebrafish for modeling adult-onset heart disease has been limited by a lack of robust methods for in vivo evaluation of cardiac function. We established a physiological protocol for underwater zebrafish echocardiography using high frequency ultrasound, and evaluated its reliability in detecting altered cardiac function in two disease models. Serial assessment of cardiac function was performed in wild-type zebrafish aged 3 to 12 months and the effects of anesthetic agents, age, sex and background strain were evaluated. There was a varying extent of bradycardia and ventricular contractile impairment with different anesthetic drugs and doses, with tricaine 0.75 mmol l(-1) having a relatively more favorable profile. When compared with males, female fish were larger and had more measurement variability. Although age-related increments in ventricular chamber size were greater in females than males, there were no sex differences when data were normalized to body size. Systolic ventricular function was similar in both sexes at all time points, but differences in diastolic function were evident from 6 months onwards. Wild-type fish of both sexes showed a reliance on atrial contraction for ventricular diastolic filling. Echocardiographic evaluation of adult zebrafish with diphtheria toxin-induced myocarditis or anemia-induced volume overload accurately identified ventricular dilation and altered contraction, with suites of B-mode, ventricular strain, pulsed-wave Doppler and tissue Doppler indices showing concordant changes indicative of myocardial hypocontractility or hypercontractility, respectively. Repeatability, intra-observer and inter-observer correlations for echocardiographic measurements were high. We demonstrate that high frequency echocardiography allows reliable in vivo cardiac assessment in adult zebrafish and make recommendations for optimizing data acquisition and analysis. This enabling technology reveals new insights into zebrafish cardiac physiology and provides an imaging platform for zebrafish-based translational research.
- Lack of an apparent role for endothelin-1 in the prolonged reduction in renal perfusion following severe unilateral ischemia-reperfusion injury in the mouse. [Journal Article]
- PRPhysiol Rep 2016; 4(21)
- Therapeutic approaches to block the progression from acute kidney injury to chronic kidney disease are currently lacking. Endothelin-1 (ET-1) is a powerful vasoconstrictor, induced by hypoxia, and pr...
Therapeutic approaches to block the progression from acute kidney injury to chronic kidney disease are currently lacking. Endothelin-1 (ET-1) is a powerful vasoconstrictor, induced by hypoxia, and previously implicated in renal ischemia-reperfusion (IR) injury. This study tested the hypothesis that blunting the vascular influence of ET-1, either through endothelin ETA receptor blockade (ABT-627) or vascular endothelial cell deletion of ET-1 (VEET KO), would improve recovery of renal perfusion and repair of injury following a severe ischemic insult in mice (45 min unilateral renal ischemia). Male C57Bl/6 mice receiving vehicle or ABT-627 commencing 2 days prior to surgery, and VEET KO mice and wild-type littermates (WT) underwent 45 min unilateral renal IR surgery followed by 28 days recovery. Renal blood velocity was measured by pulsed-wave Doppler ultrasound before and after surgery. Renal blood velocity was not significantly different between pairs of groups before surgery. Unilateral IR induced a marked reduction in renal blood velocity of the IR kidney at 24 h postsurgery in all groups, which partially recovered but remained below baseline at 28 days post-IR. Despite the lack of effect on renal blood velocity, ETA receptor blockade significantly attenuated the atrophy of the post-IR kidney, whereas this was not significantly affected by lack of endothelial ET-1 expression. These data suggest that although blockade of the ETA receptor is mildly beneficial in preserving renal mass following a severe ischemic insult, this protective effect does not appear to involve improved recovery of renal perfusion.
- Lung and cardiac ultrasound for hemodynamic monitoring of patients with severe pre-eclampsia. [Journal Article]
- UOUltrasound Obstet Gynecol 2017; 49(1):104-109
- CONCLUSIONS: Severe PE is associated with an increase in extravascular lung water, which could in part be caused by disturbed diastolic left ventricular function. Excess lung water can be identified by lung ultrasound assessment in women with severe PE before the appearance of clinical signs. Only a small proportion of these women are fluid responsive. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
- Myocardial Function Pre- and Post-Fetal Endoscopic Tracheal Occlusion (FETO) in Fetuses with Left-Sided Moderate to Severe Congenital Diaphragmatic Hernia. [Journal Article]
- UMUltraschall Med 2016 Sep 14
- Purpose: To evaluate pre- and postprocedural myocardial function in fetuses with moderate to severe congenital diaphragmatic hernia (CDH) who underwent FETO to improve survival and to reduce morbidit...
Purpose: To evaluate pre- and postprocedural myocardial function in fetuses with moderate to severe congenital diaphragmatic hernia (CDH) who underwent FETO to improve survival and to reduce morbidity and to compare these data with fetuses and CDH not undergoing FETO and normal controls. Materials and Methods: 8 fetuses with isolated left-sided CDH were included and underwent FETO at our center between 2012 and 2013. Prior to and after the operation, myocardial function was assessed by measuring the mitral annular plane systolic excursion (MAPSE), the tricuspid annular plane systolic excursion (TAPSE), Tei index, isovolumetric contraction time (ICT), ejection time (ET), isovolumetric relaxation time (IRT) for the left ventricle in PW Doppler ultrasound as well as ICT, ET, IRT and Tei index in pulsed wave tissue Doppler imaging (PW-TDI) for the left and right ventricle. The E-, A-, E'- and A'-wave peak velocity and the systolic downward motion (S') were measured for both ventricles and the E/A, E/E' and E'/A' ratios were calculated. Results: were compared to fetuses with CDH not undergoing FETO and to gestational age-matched healthy controls.
- Magnetic Nanoparticle-Mediated Targeting of Cell Therapy Reduces In-Stent Stenosis in Injured Arteries. [Journal Article]
- ANACS Nano 2016 Sep 19
- Although drug-eluting stents have dramatically reduced the recurrence of restenosis after vascular interventions, the nonselective antiproliferative drugs released from these devices significantly de...
Although drug-eluting stents have dramatically reduced the recurrence of restenosis after vascular interventions, the nonselective antiproliferative drugs released from these devices significantly delay reendothelialization and vascular healing, increasing the risk of short- and long-term stent failure. Efficient repopulation of endothelial cells in the vessel wall following injury may limit complications, such as thrombosis, neoatherosclerosis, and restenosis, through reconstitution of a luminal barrier and cellular secretion of paracrine factors. We assessed the potential of magnetically mediated delivery of endothelial cells (ECs) to inhibit in-stent stenosis induced by mechanical injury in a rat carotid artery stent angioplasty model. ECs loaded with biodegradable superparamagnetic nanoparticles (MNPs) were administered at the distal end of the stented artery and localized to the stent using a brief exposure to a uniform magnetic field. After two months, magnetic localization of ECs demonstrated significant protection from stenosis at the distal part of the stent in the cell therapy group compared to both the proximal part of stent in the cell therapy group and the control (stented, nontreated) group: 1.7-fold (p < 0.001) less reduction in lumen diameter as measured by B-mode and color Doppler ultrasound, 2.3-fold (p < 0.001) less reduction in the ratios of peak systolic velocities as measured by pulsed wave Doppler ultrasound, and 2.1-fold (p < 0.001) attenuation of stenosis as determined through end point morphometric analysis. The study thus demonstrates that magnetically assisted delivery of ECs is a promising strategy for prevention of vessel lumen narrowing after stent angioplasty procedure.
- The Inter-rater Reliability of Echocardiographic Diastolic Function Evaluation Among Emergency Physician Sonographers. [Journal Article]
- JEJ Emerg Med 2016; 51(4):411-417
- CONCLUSIONS: EP sonographers obtained similar Doppler measurements for diastolic function evaluation with very good inter-rater reliability for the assessment of overall diastolic function.
- Effects of intravenous bolus injection of nicorandil on renal artery flow velocity assessed by color Doppler ultrasound. [Journal Article]
- JCJ Cardiol 2017; 69(1):364-368
- CONCLUSIONS: Intravenous nicorandil increased renal artery blood flow velocity in comparison with nitroglycerin. Nicorandil has a significant effect on renal hemodynamics.
- Measured acoustic intensities for clinical diagnostic ultrasound transducers and correlation to the Thermal Index. [Journal Article]
- UOUltrasound Obstet Gynecol 2016 Sep 08
- CONCLUSIONS: The TIB is a poor predictor for spatial-peak temporal-average intensity, spatial-peak pulse-average acoustic intensity and potential bioeffects from clinical diagnostic ultrasound scanners.
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- Effect of selective heart rate reduction through sinus node I<sub>f</sub> current inhibition on severely impaired left ventricular diastolic dysfunction in patients with chronic heart failure. [Randomized Controlled Trial]
- ACActa Cardiol 2016; 71(3):317-22