Active clinical trials for "Constriction, Pathologic"

Elastography is a new non-invasive medical technique for measuring the stiffness at a distance from a tissue. Recent advances in the development of elastography sequences for cardiac exploration suggest a more clinical approach to cardiac elastography. This study propose to compare myocardial stiffness of a group of coronary bypass patients without hypertrophic left ventricular remodeling or sequelae of myocardial infarction versus a group of patients who should benefit from a surgical aortic valve replacement for aortic stenosis. The hypothesis is that the physiological adaptation to pressure overload constituted by aortic stenosis is responsible for a significant increase in myocardial stiffness compared to a reference group.

To collect information about treatment for severe aortic stenosis (AS), which affects the aortic valve in the heart. Aortic stenosis is a narrowing of the aortic valve opening, which decreases blood flow from the heart and causes symptoms such as chest pain, fainting and shortness of breath. The preferred treatment for severe aortic stenosis is aortic valve replacement surgery.

Prospective, single-arm, observational study with invasive coronary physiology measurements before and after transcatheter left-sided valvular intervention.

Renal artery stenosis is one the leading cause of secondary hypertension. Previous randomized controlled trials in humans have failed to demonstrate an improvement of renal function after stenosis dilation, probably because of a selection bias with more severe patients being excluded from randomization. Renal ischemia-reperfusion injuries have also not been taken into account. Indeed, reperfusion leads to a rapid renal blood flow recovery associated with renal ischemia-reperfusion injuries. Mitochondrial permeability transition pore (mPTP) is a key player in the occurrence of ischemia reperfusion injuries because its opening leads to mitochondria leakage and cell death. However, preconditioning whether pharmacological or ischemic can prevent mPTP opening and protect cells. Ciclosporin A can prolong mPTP closing during reperfusion and reduce renal and cardiac tissular lesions. Another mPTP blocker (Bendavia) has been associated with an improvement of renal blood flow (RBF) and glomerular filtration rate (GFR) after renal artery stenosis dilation at 6 weeks in pigs. Based on a recent study, dilation overall benefit could be secondary to an improvement of the contralateral kidney GFR and tissue oxygen content, requiring a single kidney evaluation of those renal functional parameters. The investigators previously demonstrated that dose and timing of ciclosporin A preconditioning is key to protect kidneys from ischemia-reperfusion injuries. Previous controlled trials that failed to demonstrate a benefit of ciclosporin A conditioning have used post conditioning on necrotic cells. Considering kidney ischemia-reperfusion injuries, preconditioning have led to more encouraging results compared to ciclosporin A post conditioning in animals. Therefore the investigators aim to conduct the first clinical study of ciclosporin A preconditioning for prevention of kidney ischemia-reperfusion injuries after renal artery stenosis dilation. Using renal functional imaging and the new PET-MRI (Positron Emission Tomography-Magnetic Resonance Imaging) combined device, the investigators will evaluate kidney perfusion, oxidative metabolism, glomerular filtration rate and oxygen content before and 3 months after renal artery stenosis dilation with or without a ciclosporin A preconditioning.

Differentiation between malignant and benign biliary strictures can be challenging. Accurate differentiation of malignant biliary strictures from benign ones is crucial to guide management decisions. While conventional tissue acquisition techniques such as brush cytology or intraductal biopsy of the biliary stricture is often performed during ERCP for tissue diagnosis, their sensitivities are suboptimal. The average sensitivities for brush cytology and intraductal biopsy were reported to be ~ 59% and ~ 63% respectively. When the cause of a biliary stricture remains unclear despite conventional ERCP techniques for diagnosis, cholangioscopy is often performed during ERCP to clarify the diagnosis. This allows an endoscopist to obtain a visual impression (VI) and to perform targeted biopsy under direct visualization of the biliary stricture. Recently, a digital SOC system (SpyGlass Digital System (SpyGlass DS), Boston Scientific, USA) has become available and has the potential to further improve the diagnosis of malignant and benign biliary strictures. The utility of this digital SOC in the evaluation of biliary strictures has not been well studied. We propose this study to evaluate the utility of the digital SOC during ERCP in the diagnosis of malignant and benign biliary strictures.

The purpose of this study is to determine the prevalence of transthyretin cardiac amyloidosis (TTR-CA) among patients with moderate and severe aortic stenosis in Southeast Minnesota using 99mTc-PYP single-photon positive emission computed tomography with computed tomography (SPECT/CT).

The goal of this clinical trial is to compare plain old balloon angioplasty with sirolimus-coated balloon angioplasty in patients with an infrainguinal venous bypass stenosis. The main question we aim to answer is, how patency is affected by each of the randomised treatment options.

Significant left main (LM) stenosis is associated with a poor prognosis, therefore, adequate judgement of the prognostic significance of LM stenosis is essential to improve patients' prognosis. Recently, fractional flow reserve (FFR) has become widespread practice and carries a Class Ia recommendation to assess functional significance of intermediate coronary stenosis in patients with stable angina. Intravascular ultrasound (IVUS)-derived minimum lumen area (MLA) represents an accurate measure to determine LM significance as shown in multiple studies, while optical coherence tomography (OCT) ,which is a novel intracoronary imaging method with a greater spatial resolution (15μm vs. 100μm), faster image acquisition and facilitated image interpretation, OCT derived-MLA has never been validated against FFR and accordingly, it is not mentioned in the current guidelines for myocardial revascularization. Coronary computed tomography angiography (CTA) has emerged as a noninvasive alternative of coronary angiography with its excellent negative predictive value, while the positive predictive value of CTA is limited. Computational fluid dynamics is an emerging method that enables prediction of blood flow in coronary arteries and calculation of FFR from computed tomography (FFRCT) noninvasively. Noninvasive and accurate assessment of functional significance would bring a great benefit for patients with LM stenosis, however, there are no data to evaluate the diagnostic accuracy of FFRCT for LM stenosis in comparison with FFR and minimal lumen area derived by OCT. This study will investigate the optimal OCT-derived MLA cut-off point and the diagnostic performance of FFRCT for intermediate LM stenosis compared with FFR ≤0.8 as a reference standard.

The CVT-SFA Trial investigates the inhibition of restenosis using the CVT Everolimus-coated PTA Catheter in the treatment of de-novo occluded/ stenotic or re-occluded/restenotic superficial femoral or popliteal arteries.

Aortic stenosis is the most common valvular disease in the Western world. It is caused by progressive narrowing of the aortic valve leading to increased strain on the heart muscle which has to work increasingly hard to pump blood through the narrowed valve. Over time the heart muscle thickens to generate more force, but eventually the heart fails leading to death if the valve is not replaced with an operation. No medical treatments exist to stop or reverse the heart valve narrowing. Current clinical guidelines suggest that an operation should be performed only when symptoms develop or the heart muscle is visibly weak on cardiac ultrasound scanning. However, symptoms can be difficult to interpret and in many patients the heart muscle has become irreversibly damaged and the heart fails to recover following surgery. Using MRI scans of the heart, the investigators have identified heart scarring which seems to develop as the heart muscle thickens. Several studies now show that people who have developed this scarring are more likely to suffer poor outcomes including death. The investigators have also identified clinical risks that predict the presence of scarring. The investigators propose a study where patients with severe aortic stenosis but no indications for valve replacement as per current guidelines are assessed for those clinical risks. If a participant's risk of having scarring is higher they will undergo a cardiac MRI scan. If scarring is present participants will be randomised to routine clinical care, or referral for valve replacement surgery. Participants with no evidence of scarring will be randomised routine care with study follow or not. The investigators of this study hypothesize that early surgery will lead to fewer complications and reduced risk of death compared to standard care.