Active clinical trials for "Renal Artery Obstruction"

Takayasu arteritis associated renal artery stenosis (TARAS) is the biggest cause of hypertension in young people <40 years old. Hypertension caused by renal artery stenosis is usually hard to control in spite of two or more anti-hypertension drugs. Percutaneous transluminal angioplasty (PTA) is recommended for hypertension caused by TARAS. In previous clinical practice, we observed relatively effects of PTA on controlling the blood pressure in patients with TARAS. But, high re-stenosis rate was also indicated. Drug coated balloon (DCB）is a new type of PTA, which could improve the re-stenosis rate significantly. In the clinical trials of peripheral vascular disease, it has been confirmed that DCB had lower re-stenosis rate than PTA. However, up to date, no studies was found about the use of DBC in TARAS. Thus, this study was design as a random, double blind trial to evaluated the effects and safety of DCB in the treatment of hypertension caused by TARAS.

The goal of this clinical trial is to document a beneficial effect of percutaneous transluminal renal angioplasty (PTRA) of atherosclerotic renal artery stenosis in high-risk patients selected according to the criteria used in the DAN-PTRA study. The main questions the trial aims to answer are if renal artery stenting compared with optimal medical treatment alone has beneficial effects on: Blood pressure Kidney function Hospitalizations for heart failure

Transplant renal artery stenosis (TRAS) is abnormal narrowing of the main blood vessel to the kidney transplant and has historically been considered a surgical complication. In heart transplantation, it has long been recognised that rejection can cause narrowing of the heart's blood vessels, and that this complication is the leading cause of heart transplant failure. It is reasonable to assume that this process may also occur in kidney transplantation, which could contribute to premature transplant failure. However, in kidney transplantation it is also likely that other factors, such as surgical factors, traditional cardiovascular risk factors and immunological factors, contribute to the development of TRAS. Given that the disease processes that cause TRAS are not fully understood, at present there is no consensus among kidney doctors on the best means of treating patients diagnosed with TRAS. The aim of the proposed study is to investigate the involvement of these different processes in the development of TRAS, and investigate the optimal way to diagnose and manage TRAS. At present, there is no standard recommendation for how to treat patients with TRAS. This is partly due to the fact that patients with TRAS may have a broad array of symptoms: Some may have no symptoms, other may have problems with high blood pressure or fluid accumulation, and others may have severe transplant dysfunction. In most transplant centres, patient TRAS and severe symptoms will undergo IADSA and a stent will be placed to open the narrowing. However, it is not clear how best to manage patients with TRAS who have mild to moderate symptoms. We propose to recruit 36 such patients to a clinical study and split them into two groups: One group to undergo IADSA with possible stent placement, and one group to be closely observed. We will then compare transplant function, and other outcomes, after one year between the two groups.

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.

Although randomized trials have demonstrated there is no benefit of renal-artery stenting in addition to medical therapy for patients with atherosclerosis renal artery stenosis, many patients indeed gained benefit in daily practices after stenting, such as reduction in blood pressure and recovery in renal functions. One important gap is that there is no universal standard to determine whether to stent in these patients. Fraction Flow Reserve (FFR) has been studied for many year in chronic coronary heart disease and FFR-guided revascularization strategy is known to be better than both angiography-guided revascularization and medication alone. The goal of this clinical trial is to learn whether Fraction Flow Reserve (FFR) is appropriate to determine stenting in hypertension patients with atherosclerosis renal artery stenosis. The main questions it aims to answer are: Is it appropriate to use FFR to determine whether or not stenting for hypertension patients with atherosclerosis renal artery stenosis? To provide detailed data supporting design of further trial, such as sample size calculating, cut-off value for FFR in renal artery stenosis, etc. Participants met the inclusive/exclusive criteria will be randomized to stenting or not in the renal artery, then hyperemic FFR induced by dopamine will be measured in all participants. If FFR is ≥0.80, randomization will be applied. If FFR is <0.80, randomization will be ignored, and stenting will be performed as planned. The blood pressure and anti-hypertensive medications will be compared before and 3 months after the procedure based on ambulatory blood pressure monitoring, all participants will be followed up for 1 year.

The study will test the efficacy of drug eluting balloon(DEB) for non-atherosclerotic renal artery stenosis. The DEB (paclitaxel eluting balloon) will be used in the intervention group, while the plain old balloon(POB) will be used in the control group. The primary outcome is the effect of blood pressure control.

A prospective Danish national registry of percutaneous transluminal renal angioplasty (PTRA) in high-risk patients with renal artery stenosis selected on the basis of common national criteria, and with a common follow-up protocol for all three Danish centres offering PTRA

A multicenter prospective registry planned to recruit more than 5 000 patients with renal artery stenosis was carried out in China. This primary purpose of this study was to evaluate the safety and efficacy of renal artery revascularization in the real world. The secondary purpose was to investigate the etiologic distribution of renal artery stenosis and optimize the indications for renal artery revascularization.

The clinical benefits of endovascular treatment in renal artery stenosis remain controversial. This study uses arterial spin labelling MRI and flat-panel detector parenchymal blood volume imaging to observe the change in renal perfusion after endovascular treatment in renal artery stenosis.

The purpose of this study is to evaluate the safety and effectiveness of the RX HERCULINK 14 Peripheral Stent System in treating atherosclerotic renal artery stenosis.