Active clinical trials for "Coronary Stenosis"

Patients planned for elective conventional coronary angiography will undergo CT coronary angiography (Dual Source CT) in order to assess the correlation of stenosis detection and therapeutic advice between conventional and CT coronary angiography. We hypothesize that their is a good correlation between conventional and CT coronary angiography for stenosis detection and therapeutic advice.

Coronary CT angiography (CTA) or invasive coronary angiography (CAG) is usually performed to evaluate the severity of coronary stenosis depending on the probability of CAD. However, the stenosis severity is not closely corresponding with the hemodynamic significance in coronary arteries. As a result, fractional flow reserve (FFR) with pressure wire measurement was introduced to functionally assess the coronary stenosis. FFR is defined as the ratio of maximum blood flow distal to a stenotic lesion under hyperemia state to normal maximum flow in the same vessel. The cutoff value of FFR to detect significant ischemia is set to be 0.80, indicating that PCI should be considered if FFR≤0.80. However, FFR does have some limitations, such as risks of pressure wire injury, extra time and cost, and side effects of hyperemic agents. To overcome the limitations of FFR, CTA- and CAG-based methods to functionally assess coronary stenosis were proposed, i.e. FFR derived from CTA (FFRCT) and FFR derived from angiography-based quantitative flow ratio (QFR), which can simultaneously evaluate anatomic and hemodynamic significance of stenotic lesions. A number of studies have demonstrated that FFRCT has high sensitivity and specificity in identifying myocardial ischemia. However, the diagnostic accuracy of FFRCT depends on the image quality of coronary CTA, and it is relatively low in lesions with severe calcification and/or tortuosity. Besides, the methodology of FFRCT relies on computational fluid dynamics, which is complicated and time consuming. As for QFR, it is a novel method for deriving FFR based on 3-dimensional quantitative coronary angiography (3D-QCA) and contrast frame counting during CAG. Recent studies have shown that QFR has good diagnostic performance in evaluating the functional significance of coronary stenosis. The accuracy of QFR is also highly associated with anatomic information, thereby its diagnostic accuracy may be decreased in diffuse, tandem, thrombus-containing, calcified, or torturous lesions, and it is not suitable for prior infarction-related or collateral donor arteries as well. Given the above issues concerning FFRCT and QFR, we proposed a novel approach that integrates coronary CTA and CAG images to calculate FFR (FFRCT-angio) using artificial intelligence. The present study was undertaken to test the diagnostic accuracy of FFRCT-angio in patients with SCAD.

The investigators propose to develop a computational framework involving a novel automatic image segmentation algorithm based on CTA images, an artery model reconstruction algorithm for stenosis detection, and quantification of severity of stenosis in terms of area stenosis.

The registry aims to evaluate the safety, performance and efficacy of the Everolimus-eluting bioresorbable vascular scaffold (BVS) system following rotational atherectomy in patients with complex de novo native coronary artery lesions in all-day clinical practice.

The trial will investigate the accuracy of Dual Source CT coronary angiography to detect coronary artery stenoses in patients with chest pain who have, based on clinical criteria, an intermediate likelihood for the presence of coronary artery stenoses. No beta blockers will be used to lower the heart rate for the examination. The hypothesis is that Dual Source CT will allow the detection of vessels with at least one coronary artery stenosis with a sensitivity of more than 90%.

Regional absolute myocardial blood flow during stress (sMBF) as measured by Positron Emission Tomography (PET) improves post mechanical revascularization provided there is a baseline stress induced perfusion defect. Coronary revascularization performed on regions without a stress induced perfusion defect does not increase the sMBF.

A multicenter, prospective, observational cohort study with clinical, quality of life, and economic evaluation to ascertain the quality-adjusted life years (QALYs) gained by patients with ischemic heart disease revascularized with Absorb in standard clinical practice in Spain. A before-after comparative analysis will be performed, so that each patient will act as his/her own control.

Revascularization of borderline coronary stenoses (40-70%) is usually driven by fractional flow reserve (FFR) which expresses the physiological significance of a lesion and tells the operator whether PCI may reduce the rate of adverse events as compared to medical therapy. Coronary stenoses with FFR value < 0.80 are indeed associated with a higher rate of adverse event and requires coronary revascularization whereas lesions with FFR > 0.80 show an excellent prognosis which cannot be improved by coronary stenting. Such a predictive value of FFR is theoretically based only on the degree of myocardial ischemia downstream from a given coronary stenosis: however, also plaque composition may play a crucial role in triggering future events especially in patients affected by acute coronary syndrome. Differences in plaque composition between FFR-positive and FFR negative lesions have never been assessed. Intracoronary Near-InfraRed Spectroscopy (NIRS) identifies lipid rich plaques that can potentially cause acute events. The aim of this study is to compare the lipid content expressed by LCBI (Lipid Core Burden Index) between functionally significant (FFR < 0.80) and non-significant (FFR > 0.80) stenoses in patients undergoing coronary angiography because of stable CAD and non-ST elevation acute coronary syndromes. This is an observational, prospective, multicentric study where we plan to collect 150 coronary lesions.

Coronary fraction flow reserve (FFR), the ratio of the mean coronary pressure distal to a coronary stenosis to the mean aortic pressure during maximal coronary blood flow (hyperemia), defines the hemodynamic significance of coronary artery narrowing. Noninvasive assessment of FFR via a combination of computational fluid dynamics (CFD) and coronary CT angiography CCTA (the so-called FFRCT) has potential. Coronary computed tomographic angiography is a noninvasive test for diagnosis of anatomic coronary stenosis (i.e., narrowing of a blood vessel). A new analytical model of FFR from the general Bernoulli equation (conservation of energy) (FFRB) is simple and has potential. A collaborator group has recently developed a new analytical model to quantify pressure drop, and hence FFR, based on lesion dimensions (i.e., the cross-section area along the lesion and the length of lesion) and coronary flow, with no empirical parameters. The investigators hypothesize that this new model will allow quantification of FFR (FFRB) in a cohort of human patients with intermediate coronary stenosis. The study will compare FFRB with invasive FFR measurements from invasive coronary angiography (ICAG).

A multicenter, retrospective clinical study was carried out in the medical records management system of 6 hospitals in Tianjin. Patients who were suffered with Coronary heart disease angina pectoris and underwent coronary angiography are collected. The investigators collect and analyze the demographics, laboratory information, clinical outcome data, and coronary angiographic data of patients. To explore the correlation between hypercholesterolemia and the degree of coronary artery stenosis of Coronary heart disease angina pectoris, and to further research the influence of hypertension on total cholesterol level and coronary artery stenosis, and provide guidance for clinical prevention and treatment.