Active clinical trials for "Constriction, Pathologic"

A prospective study of 600 patients with severe aortic stenosis (AS) and symptoms who underwent TAVI at the Haukeland university hospital, Bergen, Norway.

Diabetes is associated with an increased risk of cardiovascular complications, as a reflection of the chronic inflammatory status. Monocytes-macrophages in diabetic subjects present impaired arachidonic acid metabolism. Moreover, atheromatous plaques in diabetic subjects seem to be significantly enriched in 2-AA-LPC (2-arachidonoyl-lysophosphatidylcholine) and are more inflammatory and more likely to rupture than are plaques in non-diabetic subjects. We therefore hypothesize that this vulnerability of atheromatous plaques in diabetic subjects could be explained by impaired 2-AA-LPC metabolism within the plaque.

Ischaemic stroke is a major cause of death and disability worldwide. In patients with recent stroke, the 18F-fluoride positron emission tomography-computed tomography highlights high-risk culprit carotid plaque and is more discriminatory than 18F-fluorodeoxyglucose. Using hybrid positron emission tomography-magnetic resonance imaging investigators propose to build upon these findings by prospectively assessing 18F-fluoride uptake in a broad range of patients with acute transient ischaemic attack or ischaemic stroke. Investigators will specifically examine the association of 18F-fluoride uptake with multiparametric magnetic resonance imaging assessments of atherosclerotic plaque, especially the role of thrombus and lipid. Finally, using transcranial Doppler and diffusion-weighted magnetic resonance brain imaging, an assessment of the functional consequences of 18F-fluoride-positive atherosclerotic plaque will be performed. If successful, this technique has a number of valuable translational applications including the better selection of patients for carotid intervention.

Prospective, multi-centre, multi-national registry with a follow-up of 3 months, in five European countries and Canada (Toronto), with elective patients undergoing TF-TAVI (n=120) and isolated SAVR (n=120), respectively and a control group of 50 patients receiving medical treatment only. All patient groups will fill in three different questionnaires to assess quality of life in 5 different languages (English, French, German, Italian and Spanish). One of these will be a new questionnaire, the Toronto Aortic Stenosis QoL (Quality of Life) questionnaire (TASQ).

As for today, transcatheter aortic valve implantation (TAVI) is indicated only in symptomatic patients with severe aortic stenosis (AS) at high surgical risk. As cancer therapy improves, some AS patients suffering active malignancy (including advanced metastatic diseases) may be more endangered by their untreated valvular disease than their oncological disease. Among these patients, TAVI may be indicated before cancer related surgery or cardiotoxic anti-cancer therapy in order to achieve better anti-cancer therapy outcomes. Individualized life expectancy assumptions should be evaluated by the heart team in the clinical decision-making process as an essential factor in weighing the risk-benefit ratio for oncologic patients undergoing TAVI. A multicenter, international TAVI in Oncology Patients with AS (TOP-AS) registry was designed to collect data on patients with an active malignancy and severe AS undergoing TAVI. The aim of the study is to evaluate the outcomes, benefits and risks of oncology patients undergoing TAVI, mainly the patients' survival and cause of death and also the interactions between the valvular and the oncologic conditions.

Exertional angina is common symptom in patients with severe aortic stenosis (AS) without obstructive coronary artery disease (CAD). Although reduced myocardial flow reserve is one of the proposed explanations for angina, little is known about the pathophysiology. This study aimed that adenosine-stress cardiac magnetic resonance can be used for the assessment of myocardial perfusion reserve and suggest the pathophysiology of development of angina in patients with severe AS without obstructive CAD.

Aortic stenosis (AS) is the most common valve disease in the United States and most common indication for valve replacement surgery. Anatomical and hemodynamic severity of AS is insufficient for elucidating patients' prognosis. Therefore, the decision about the optimal timing of surgical intervention remains critical. However, the changes in structure and electrical activity of the cardiac muscle can be assessed by noninvasive imaging and electrocardiography (ECG). Degenerative myocardial changes characterized by fibrosis or collagen deposits are frequently observed in AS patients and have a negative impact on patient outcomes. In this project, our objective is to determine whether echocardiographic image analysis of integrated backscatter (IB), which can express changes in myocardial tissue composition (amount of fibrosis) based on its ultrasound reflectivity, global left ventricular (LV) load as measured by Zva, and ECG analysis of the duration of the QRS interval have a role in risk stratification for AS patients and to apply those methods to identify which patients would benefit from surgical intervention. The investigators hypothesize that 1) the severity of myocardial damage can discriminate the prognosis in patients with AS, and 2) IB, Zva, and QRS interval can be diagnostic measures of the severity of myocardial damage. The investigators will measure the severity of myocardial fibrosis using MRI (reference) in 50 patients and will test the diagnostic significance of IB (testing method). Zva, QRS duration, and conventional echocardiographic measures will also be tested for diagnosing severity of myocardial fibrosis.

The rate of success 12 months after surgery is reported to be 60-65% in patients with lumbar disc herniation and 60-70% in patients with spinal stenosis. At the Back Center Copenhagen, patients with persistent low back pain caused by lumbar disc herniation and spinal stenosis are treated by a multidisciplinary team comprising rheumatologists, physiotherapists, chiropractors, and social workers according to current guidelines. Therefore we have a unique opportunity to report the long term outcome in candidates for surgery, regardless of whether they have surgery or not, after having received optimal but unsuccessful nonsurgical treatment. The purpose of this study is to answer the following questions: 1) What is the proportion of patients operated upon after referral to surgical evaluation with positive MRI findings, persistent low back pain, and poor outcome following non-operative treatment? 2) What was the outcome in these patients 2 years following referral? 3) Where any baseline variables predictive of good or poor postsurgical outcome? 4) Where there any difference in outcome in patients with or without surgery?

Fractional flow reserve (FFR) is a pressure-wire-based index that is used during coronary angiography to assess the potential of a coronary stenosis to induce myocardial ischemia. Recent ESC guidelines referred to the usefulness of FFR extensively when noninvasive stress imaging is contraindicated, non-diagnostic, or unavailable. However, FFR requires additional manipulation with maximal and stable hyperemia by intravenous adenosine. More routine use of FFR for all angiographically significant stenoses would add considerable time, cost, and complexity to each PCI procedure and might also increase the risk of catheter-related complications such as coronary dissection and perforation. Although the guideline mentioned that FFR may not be useful in very high grade lesions (angiographically >90%) which always have an FFR <0.80, it have not been revealed yet proper criteria to predict FFR <0.80 obtained by angiographic parameters including degree of stenosis, lesion location and vessel size. It would be valuable to find more precise criteria available by conventional angiography for discrimination of functional stenosis in way to reduce the risk of additional procedure. For the purpose, the investigators will perform FFR in the lesions with significant stenosis (>70% diameter stenosis by visual estimation) and compare the angiographic parameters and FFR values in the study.

The overall aim of this work is to assess the relationship between stroke risk and hemodynamic compensation strategies, as measured using a novel 3.0 Tesla MRI protocol, in patients with symptomatic intracranial (IC) steno-occlusive disease. Recent studies have shown high two-year ischemic stroke rates in symptomatic patients with IC arterial stenosis. Therapy for IC stenosis patients includes revascularization with angioplasty, IC stenting, or bypass, however identification of patients most likely to benefit from these more aggressive interventions, rather than medical management alone, has been problematic. Accurate measurements of hemodynamic compromise are likely required to better define stroke risk and guide treatment decisions. Specifically, in IC stenosis patients with compromised cerebral perfusion pressure (CPP), the extent of hemodynamic compromise reflects the autoregulatory capacity of vasculature to increase arterial cerebral blood volume (aCBV) and/or develop collaterals to supplement cerebral blood flow (CBF). The prevalence of CBF collateralization and aCBV autoregulation has been hypothesized to correlate uniquely with stroke risk, however the extent of this correlation has been debated. The critical barrier to stratifying stroke risk rests with a lack of (i) methodology for measuring multiple hemodynamic factors with high specificity and (ii) noninvasive approaches capable of monitoring longitudinal progression of impairment. The investigators have demonstrated the clinical utility of relatively new, noninvasive MRI approaches for assessing cerebrovascular reactivity (CVR), aCBV, and collateral CBF. The investigators hypothesize that stroke risk can be more completely evinced from collective measurements of these parameters. Therefore, the investigators propose to implement a novel, validated hemodynamic MRI protocol to assess tissue-level impairment and compensation strategies in patients with IC stenosis. Using a collective approach combining measurements of collateral CBF, aCBV and CVR in multiple brain regions, in conjunction with a statistical model incorporating the above variables as possible prognostic factors, the investigators will quantify the extent to which two-year stroke risk is associated with hemodynamic compensation mechanisms. The noninvasive and multi-faceted scope of this investigation is intended to expand the diagnostic stroke infrastructure and elucidate new hemodynamic prognostic indicators of stroke in this high-risk population.