Active clinical trials for "Myocardial Infarction"

Coronary artery stents, particularly drug-eluting stents (DES), are used in the majority of patients who undergo percutaneous coronary intervention (PCI) to improve symptoms in patients with obstructive coronary artery disease. They function both to prevent abrupt closure of the stented artery soon after the procedure as well as to lower the need for repeat revascularization compared to balloon angioplasty alone . Stent restenosis and stent thrombosis are potential complications of coronary artery stenting; their incidence is highest in the first year after PCI. Stent restenosis, which occurs more frequently with bare metal stents (BMS) than DES, may occasionally present as an acute myocardial infarction (MI). Stent thrombosis is an uncommon but serious complication that often presents as death and is almost always accompanied by MI, usually with ST-segment elevation. Patients are commonly treated with dual antiplatelet therapy (DAPT) for the recommended duration for the particular stent. DAPT (aspirin plus platelet P2Y12 receptor blocker) and significantly lowers the risk of stent thrombosis.

In chest pain patients with suspected acute coronary syndrome, a 2-hr delta Troponin-I as measured by the i-STAT immunoassay reliably identifies and excludes an acute myocardial infarction. In chest pain patients with suspected acute coronary syndrome whose baseline troponin is above the 99th percentile but less than 0.2ng/ml, a 2hr delta Troponin-I as measured by the i-STAT immunoassay accurately discriminates between acute myocardial infarction and non-acute myocardial infarction troponin elevations.

Hypothesis: High sensitivity cTnI assays will have improved diagnostic accuracy for type 1 MI compared to contemporary cTnI assays. The primary objective of the study is to determine the performance of a high sensitivity cardiac troponin I (hs-cTnI) assay compared to a contemporary cTnI assay for the diagnostic accuracy of type 1 acute myocardial infarction (AMI). The diagnostic performance of Abbott's hs-cTnI assay will be evaluated. Investigators will assess the assay's ability to diagnose AMI earlier and to rule out AMI earlier. The sensitivity, specificity, positive predictive value and negative predictive value of the hs-cTnI assay will be evaluated with both a universal cut off as well as with gender and potentially age derived 99th percentile upper reference limits (URL). Investigators will evaluate delta hs-cTnI values (pre-specified absolute concentration and percent changes over time) for their ability to contribute to the negative predictive value and hence potentially lead to an earlier rule out of AMI (improved specificity). Additionally, investigators will assess delta changes of the hs-cTnI assay for their potential contribution to the clinical differentiation of type 1 and type 2 (supply demand mismatch) MIs. Lastly, investigators will compare the diagnosis of AMI based on the currently used contemporary assay to the hs-assay, to assess both the incidence of AMI as well as for the time to diagnosis.

Cardiac magnetic resonance imaging (CMR) is a non invasive technique used to obtain functional and anatomical information on the heart. Several CMR parameters measured after primary percutaneous coronary intervention (PPCI) have been shown to have prognostic value and are increasingly being used as surrogate endpoints in clinical trials. Myocardial oedema is a prognostic indicator following myocardial infarction1. Myocardial salvage is calculated as the myocardial oedema minus infarct size; this again is a prognostic indicator following STEMI. However, myocardial oedema imaging is controversial. There are multiple sequences available, with no standardisation of sequences used to assess this surrogate endpoint. The investigators propose to conduct a study to measure the myocardial oedema by all available techniques to determine the agreement between these methods.

The purpose of this study is first to evaluate absolute myocardial blood flow and resistance over time in the acute and sub-acute phase of myocardial infarction and second, to correlate these parameters to preservation of left ventricular function and long-term outcome.

BACKGROUND: Non-ST-segment elevation myocardial infarction (NSTEMI) is the commonest type of acute coronary syndrome (ACS) and has a poor long-term prognosis. Guidewire-based coronary pressure measurement of the myocardial fractional flow reserve (FFR) is validated for measuring the severity of a coronary lesion narrowing in patients with stable angina. FFR measurement in patients with a recent ACS has theoretical limitations and is not fully validated. AIM: To prospectively assess heart muscle blood flow and injury with guide-wire based methods at the time of the clinically-indicated angiogram and compare these results with those from a stress perfusion MRI scan in medically-stabilised NSTEMI.. HYPOTHESIS: 1) FFR measured invasively will correspond closely with findings from stress perfusion MRI, 2) MRI will provide clinically-relevant information on heart muscle injury, function and salvage, 3) Guidewire-derived measurements of coronary microvascular function will be associated with the MRI findings. DESIGN: The MRI study will be performed in patients who give informed consent in the FAMOUS-NSTEMI clinical trial (NCT registration 01764334). All of the clinical data for these participants will be available to link with the MRI results.

In Emergency Departments patients admitted with chest pain may suffer from non-significant to lifethreatening conditions. The aim of the present study is to develop and validate a referral model in chest pain patients which divide the patients with non- significant ECG changes into high risk and low risk groups for acute coronary syndrome.

Cardiovascular disease (CVD) is an important public health problem that affects millions of people worldwide. Associations between risk factors, such as smoking, dyslipidaemia or hypertension, and prevalent CVD are well documented. However, few studies have investigated associations with onset of disease. The initial manifestation of CVD, for example an episode of unstable angina, is important because it influences the prognosis, the quality of life and the management of disease. Furthermore, the extent to which social deprivation, alcohol consumption or atrial fibrillation affects presentation of CVD is poorly understood and deserves further consideration. Most previous studies have considered CVD as a single entity. However, differences in aetiology between coronary phenotypes suggest that risk factors may not be shared across specific coronary phenotypes and their relative importance is likely to differ for each phenotype. Gaining knowledge of these differences could provide insights into the pathophysiology of specific forms of CVD and could eventually lead to modification of recommendations for patient management and disease prevention. We propose to use the linkage of the national registry of coronary events to general practice records in the Clinical Practice Research Database (CPRD), to investigate whether demographic, behavioral, and clinico-metabolic risk factors differentially influence the onset of specific types of CVD.

This project aims to refine previous studies including the investigators work recently published in August 2012 Journal Thrombosis and Thrombolysis. That study showed a relationship between the level of platelet leukocyte aggregates in patients with acute coronary syndrome. The investigators intend to compare the characteristics of platelets, monocytes and neutrophil data of volume, scatter and conductivity obtained from routine blood count level with flow cytometry results defining platelet leukocyte aggregates. The investigators hypothesize that there will be a direct correlation between elevated platelet-leukocyte aggregates and biophysical data from the blood count.

The objective of this five-year prospective observational follow-up study is to examine the additional benefits of using cardio-ankle vascular index (CAVI) as a predictive indicator of cardiovascular events in high-risk patients.