Active clinical trials for "Constriction, Pathologic"

We sought to determine whether the dual-source computed tomography assessment of aortic valve stenosis and coronary artery disease is equivalent to or even better than conventional invasive coronary angiography and transthoracic echocardiography.

Narrowing of coronary arteries interferes with blood flow and can cause chest pain. Cardiologists sometimes quantify the extent of the narrowing by measuring the fractional flow reserve (the ratio of the pressure in the aorta to the pressure downstream of the narrowing under conditions of maximal flow). We propose a new technique based on principles of wave intensity analysis (WIA) to better assess coronary stenosis and the significance of the narrowing without the need for administration of vasodilator agents such as adenosine. This would simplify assessment and improve our ability to advise patients whether stent treatment will help their symptoms.

This study will evaluate the relationship of Fractional Flow Reserve (FFR) and Minimal Lumen Area (MLA) by IntraVascular UltraSound (IVUS) by comparing the results of the both tests which is done as a part of the cardiac catheterization.

Vibration response imaging (VRI) technology, provides a radiation-free dynamic image of the lung, by visualizing vibration energy emitted during the respiration cycle (lung sounds). Airflow in the lungs during the respiration cycle creates vibrations that propagate through the lung tissue; these vibrations are affected by the structural properties of the lungs and may vary in space, time and frequency. Moreover, any structural alteration, such as a bronchial obstruction or space occupying infiltration, is reflected in a corresponding modification of the vibration response. As obstructions that occur in airways alter airflow, the VRI may provide additional lung function information prior to treatment for airway obstruction and during follow-up. Moreover, the VRI may provide the physician immediate evaluation of the improvement of air flow distribution, quantitative and qualitative measurements. Furthermore, the VRI is a non-invasive, radiation free procedure which is simple and doesn't require the level of patient effort required for lung function test and other evaluation.

Aortic valve stenosis (AVS) is the most frequent valvular disease. The severity of the obstruction of the left ventricle (LV) is essentially analyzed today by echocardiography Doppler, which assesses two key markers that are aortic valve pressure gradient and the aortic valve area. however these marker are a poor reflect of the clinical severity of AVS. The aim of the study is to validate new markers assessing cardiac fibrosis that might best or complementary markers.

To establish a registry in order to collect and analyze baseline and outcome data on patients with severe valvular stenosis treated with balloon valvuloplasty.

To use a new statistical method, the Logical Analysis of Data (LAD), to predict cardiac surgery risk.

The investigators plan to collect 30 participants with internal carotid artery stenosis to observed the relationship between the degree of internal carotid artery stenosis and fundus vessels （and blood flow）density before operation, and compared with participants without internal carotid artery stenosis.The fundus blood flow density will be observed after intervention operation in order to see whether the operation is effective to improve the density of fundus vessels and blood flow or not.

Aortic stenosis is the most common valve disease requiring surgery in the Western world. It is defined by progressive calcification and fibrosis of the valve leaflets and restricted valve opening. This in turn exposes the heart muscle (left ventricle) to increasing pressure leading to heart muscle thickening (left ventricular hypertrophy, LVH) to normalise wall stress and maintain heart output (stroke volume). The only treatment available is relief of pressure overload by surgical or minimally invasive valve replacement (TAVI). Transthyretin (TTR) amyloidosis is a condition characterised by deposition of insoluble transthyretin protein (a small protein tetramer produced in the liver) in various tissues, predominantly in the heart. Although there are inherited forms caused by specific TTR gene mutations, most cases occur in older individuals with non-mutated TTR (wild-type). The finding of TTR plaques in elderly individuals is relatively common; in a post-mortem study 22-25% of patients over the age of 80 had evidence of cardiac amyloid deposition. However, there is significant progressive amyloid accumulation in a small percentage of individuals leading to heart muscle thickening and heart failure. No medical treatments are currently licensed although several agents are at advanced stages of clinical trials. As both the above conditions are increasingly common in the elderly population and characterised by increased heart muscle thickening, there is the potential for them to coexist unrecognised in individual patients. The prevalence of cardiac amyloidosis in clinical populations with significant aortic stenosis is not known however small series have estimated somewhere in the region of 6-29%. Other data have suggested that patients with aortic stenosis and concurrent cardiac amyloidosis have an adverse prognosis even despite AVR. It is therefore important to identify aortic stenosis patients with coexistent amyloidosis both in terms of predicting prognosis and because it may influence decisions about whether to proceed to valve intervention. PET/MR is an emerging technique, which combines the excellent temporal and spatial resolution of MRI with the sensitive molecular imaging of PET. PET/MR has significant advantages over PET/CT (the currently more widely used approach) in that it offers superior tissue characterisation, improved correction for cardiac and respiratory motion and major reductions in radiation exposure. Whilst there are concerns about its ability to provide reliable attenuation correction of the PET data, these issues appear to have been largely overcome with recent techniques proposed by our group. MR is also more naturally suited to the imaging of certain tissues in the body compared to CT including the left ventricular myocardium. In aortic stenosis, MRI has become the gold-standard technique for examining the heart muscle (myocardium) with the unique ability to assess its tissue composition. In particular both late gadolinium enhancement (LGE) and T1 mapping based techniques are able to detect heart scarring (fibrosis) which act as biomarkers of left ventricular decompensation and are strongly associated with poor patient outcomes. CMR is also the gold-standard non-invasive technique for detecting cardiac amyloid, which is associated with both a characteristic pattern of LGE and high native T1 values. However it is not currently able to differentiate between the two different types of cardiac amyloid TTR and AL amyloidosis, which have different prognoses and treatments. Preliminary studies conducted by our group have suggested that 18F-NaF PET when added to CMR can make this distinction on the basis that this tracer binds to TTR deposits but not AL deposits, may be able to differentiate between the two. Importantly we have also used the same PET tracer as a marker of calcification activity in the aortic valve, demonstrating its ability to predict disease progression and cardiac events. In this study, we will investigate whether PET/MR could be used as "one-stop" imaging in aortic stenosis in whom valve intervention is being considered to assess in detail functional and structural properties of both the valve and myocardium and identify cases of significant cardiac TTR amyloid deposition.

Multicentre prospective registry including consecutive patients undergoing Percutaneous Endovascular Aneurysm Repair (PEVAR), Percutaneous Endovascular Thoracic Aneurysm Repair (PTEVAR) or Transcatheter Aortic Valve Implantation (TAVI) in which variables related to the percutaneous access closure for implanting devices at aorta level will be collected and analyzed. The follow-up period will be 30 days after the procedure. The duration of the recruitment period will be one year. All data will be collected telematically and incorporated into a database for subsequent statistical analysis. There will be 2 points for data interim analysis at 6 and 12 months after initiation of the study.