Project description:Pulmonary arterial hypertension (PAH), a rapidly fatal vascular disease, strikes women more often than men. Paradoxically, female PAH patients have better prognosis and survival rates than males. The female sex hormone 17?-estradiol has been linked to the better outcome of PAH in females; however, the mechanisms by which 17?-estradiol alters PAH progression and outcomes remain unclear. Because proximal pulmonary arterial (PA) stiffness, one hallmark of PAH, is a powerful predictor of mortality and morbidity, we hypothesized that 17?-estradiol attenuates PAH-induced changes in mechanical properties in conduit proximal PAs, which imparts hemodynamic and energetic benefits to right ventricular function. To test this hypothesis, female mice were ovariectomized and treated with 17?-estradiol or placebo. PAH was induced in mice using SU5416 and chronic hypoxia. Extra-lobar left PAs were isolated and mechanically tested ex vivo to study both static and frequency-dependent mechanical behaviors in the presence or absence of smooth muscle cell activation. Our static mechanical test showed significant stiffening of large PAs with PAH (P<0.05). 17?-Estradiol restored PA compliance to control levels. The dynamic mechanical test demonstrated that 17?-estradiol protected the arterial wall from the PAH-induced frequency-dependent decline in dynamic stiffness and loss of viscosity with PAH (P<0.05). As demonstrated by the in vivo measurement of PA hemodynamics via right ventricular catheterization, modulation by 17?-estradiol of mechanical proximal PAs reduced pulsatile loading, which contributed to improved ventricular-vascular coupling. This study provides a mechanical mechanism for delayed disease progression and better outcome in female PAH patients and underscores the therapeutic potential of 17?-estradiol in PAH.
Project description:AimsThis study aimed to evaluate a novel echocardiographic algorithm for quantitative estimation of pulmonary artery wedge pressure (PAWP) and pulmonary vascular resistance (PVR) in patients with heart failure and pulmonary hypertension (PH) scheduled to right heart catheterization (RHC).Methods and resultsIn this monocentric study, 795 consecutive patients (427 men; age 68.4 ± 12.1 years) undergoing echocardiography and RHC were evaluated. Multiple regression analysis was performed to identify echocardiographic predictors of PAWP and PVR measured by RHC in the derivation group (the first 200 patients). The diagnostic accuracy of the model was then tested in the validation group (the remaining 595 patients). PH was confirmed by RHC in 507 (63.8%) patients, with 192 (24.2%) cases of precapillary PH, 248 (31.2%) of postcapillary PH, and 67 (8.4%) of combined PH. At regression analysis, tricuspid regurgitation maximal velocity, mitral E/e' ratio, left ventricular ejection fraction, right ventricular fractional area change, inferior vena cava diameter, and left atrial volume index were included in the model (R = 0.8, P < 0.001). The model showed a high diagnostic accuracy in estimating elevated PAWP (area under the receiver operating characteristic curve = 0.97, 92% sensitivity, and 93% specificity, P < 0.001) and PVR (area under the receiver operating characteristic curve = 0.96, 89% sensitivity, and 92% specificity, P < 0.001), outperforming 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging recommendations (P < 0.001) and Abbas' equation (P < 0.001). Bland-Altman analysis showed satisfactory limits of agreement between echocardiography and RHC for PAWP (bias 0.7, 95% confidence interval -7.3 to 8.7) and PVR (bias -0.1, 95% confidence interval -2.2 to 1.9 Wood units), without indeterminate cases.ConclusionsA novel quantitative echocardiographic approach for the estimation of PAWP and PVR has high diagnostic accuracy in patients with heart failure and PH.
Project description:A greater understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary artery hypertension (PAH) has led to significant advances, but the disease remains fatal. Treatment options are neither universally available nor always effective, underscoring the need for development of novel therapies and therapeutic strategies. Clinical trials to date have provided evidence of efficacy, but were limited in evaluating the scope and duration of treatment effects. Numerous potential targets in varied stages of drug development exist, in addition to novel uses of familiar therapies. The pursuit of gene and cell-based therapy continues, and device use to help acute deterioration and chronic management is emerging. This rapid surge of drug development has led to multicenter pivotal clinical trials and has resulted in novel ethical and global clinical trial concerns. This paper will provide an overview of the opportunities and challenges that await the development of novel treatments for PAH.
Project description:Congenitally absent internal carotid artery with intercavernous anastomosis is an exceedingly rare vascular anomaly. We report such a case in a 65-year-old man with chronic symptoms resembling sporadic transient ischemic attacks. While these patients are usually asymptomatic due to compensatory collateralization, they are at increased risk of aneurysm formation, and thus proper identification is important. This report serves as both a case of a very rare anomaly and as a lesson on how to avoid this misdiagnosis by carotid duplex sonography. Additionally, we review the limited number of published cases of congenitally absent internal carotid artery with intercavernous anastomosis.
Project description:Background:Revascularization of posterior circulation is essential in patients with severe bilateral vertebral artery (VA) stenosis despite administering maximal medical treatment, due to the high mortality of posterior circulation stroke. Case Description:We present a 69-year-old man with bilateral severe VA stenosis at the origins, treated with occipital artery (OA)-distal VA anastomosis. Conclusion:Endovascular treatment and other surgical treatments, such as bypass grafting, are effective, but OA-VA anastomosis is a safe and effective procedure for revascularization of the posterior circulation.
Project description:Aneurysms involving the origin of the posterior inferior cerebellar artery (PICA) have a greater incidence of fusiform morphology, intraluminal thrombi, and wall calcifications. At times, a complex treatment strategy with vessel occlusion and revascularization using a bypass graft is necessary for successful obliteration of these aneurysms. The occipital artery (OA) is often the preferred donor graft for lesions of the posterior fossa because of its proximity to the target recipient vessels. However, dissection of an OA can be challenging, given its anatomically tortuous path and the presence of thick surrounding muscles. This video captures the dissection of the OA using an unconventional, "inside-out" harvesting technique and the end-to-side anastomosis of the OA to the PICA at the p3 segment. This was performed in a 58-year-old man who presented with a subarachnoid hemorrhage (Hunt and Hess grade IV) from a ruptured fusiform aneurysm located at the origin of the right PICA. Major steps in Video 1 during this case include 1) dissection and harvesting of the OA using the "inside out" technique, 2) placement of 2 temporary clips occluding the PICA and isolating the P3 segment, 3) end-to-side OA-P3 anastomosis, and 4) removal of the temporary clips and confirmation of the PICA's patency using intraoperative indocyanine green. Due to the potential for infarction of the brainstem, the patient was started on dual antiplatelet therapy postoperatively. The patient tolerated the procedure well and suffered no major complications related to the operation or from being placed on dual antiplatelet therapy. He did experience some mild, posterior neck pain and rigidity at the time of his 3-month follow-up, likely due to nerve injury that occurred while harvesting the OA. Overall, the patient remains in good neurologic status 1 year after the operation. Complex fusiform aneurysms at the origin of PICA can be successfully treated via an OA-PICA bypass.
Project description:Because lipid bilayers can bend and stretch in ways similar to thin elastic sheets, physical models of bilayer deformation have utilized mechanical constants such as the moduli for bending rigidity (?C) and area compressibility (KA). However, the use of these models to quantify the energetics of membrane deformation associated with protein-membrane interactions, and the membrane response to stress is often hampered by the shortage of experimental data suitable for the estimation of the mechanical constants of various lipid mixtures. Although computational tools such as molecular dynamics simulations can provide alternative means to estimate KA values, current approaches suffer significant technical limitations. Here, we present a novel, to our knowledge, computational framework that allows for a direct estimation of KA values for individual bilayer leaflets. The theory is based on the concept of elasticity and derives KA from real-space analysis of local thickness fluctuations sampled in molecular dynamics simulations. We explore and validate the model on a large set of single and multicomponent bilayers of different lipid compositions and sizes, simulated at different temperatures. The calculated bilayer compressibility moduli agree with values estimated previously from experiments and those obtained from a standard computational method based on a series of constrained tension simulations. We further validate our framework in a comparison with an existing polymer brush model and confirm the polymer brush model's predicted linear relationship with proportionality coefficient of 24, using elastic parameters calculated from the simulation trajectories. The robustness of the results that emerge from the method allows us to revisit the origins of the bilayer mechanical (compressible) thickness and in particular its dependence on acyl-chain unsaturation and the presence of cholesterol.
Project description:Pulmonary Artery banding (PAB) is limited to selected patients who cannot undergo primary repair due to complex anatomy, associated co-morbidities, as a part of staged univentricular palliation, and for preparing the left ventricle prior to an arterial switch operation. We report a catastrophic iatrogenic complication in which the pulmonary artery was injured during the PAB. We discuss its multi-pronged management.