Clinical Research Directory

Identification of Lesion Characteristics in Coronary Plaques Using Multimodality Intravascular Imaging and Novel Photon-counting CT in Stable Angina

Coronary artery disease, caused by the furring up of the heart arteries by atherosclerosis, is a major cause of death in the UK. Despite existing therapies, adverse cardiovascular events remains high, especially in patients who have already had a heart attack, as some of these patients have aggressive atherosclerotic disease. If we could identify these vulnerable patients, then in wider clinical practice in the future we might be able to treat them better with new therapies that can otherwise be expensive or come with a risk of side-effects. Traditionally, the assessment of atherosclerotic disease and the identification of the plaques that will cause heart attacks is performed using invasive imaging - imaging taken by passing a wire into the arteries of the heart that has a camera on its tip. Invasive imaging, however, can be used only in patients with symptoms and has risks. Photon counting (PC) CT is a new CT system that has image quality comparable to invasive imaging and can be used in the community to examine individuals with stable angina symptoms. In this study we aim to compare how well PC-CT detects high-risk plaques compared with invasive imaging and in due course develop a platform that will expedite the analysis of CT images to allow its broad use in the clinical practice.

Study of Lesion-Specific Invasive Haemodynamic Angina Thresholds

ORBITA-SOLAR is an invasive physiological cardiac catheterisation study that aims to determine whether different coronary stenoses have different angina thresholds. The angina threshold is defined as the amount of coronary flow reduction required to reproduce symptoms. Sixty patients with symptoms of stable angina and 2 coronary artery stenoses amenable to percutaneous coronary intervention (PCI) will be recruited. This study will use intra-coronary balloon inflation during supine exercise on an ergometer to measure the fractional flow reserve (FFR) and non-hyperemic pressure ratio (NHPR) that relates to angina onset, in real time, at the location of each stenosis.