The PressureWire fractional flow reserve measurement system for coronary artery disease

Introduction

Coronary heart disease causes around 94,000 deaths each year in the UK (Ludman 2013a,b). Atherosclerosis is a disease process in which fat accumulates in the coronary arteries leading to fatty plaques that are visible on angiogram.

Stable angina occurs when the blood flow to the heart is restricted by a narrowing of the coronary arteries. It causes chest pain after physical exercise or stress. There is a risk that it may lead to acute coronary syndrome, including unstable angina and myocardial infarction. In myocardial infarction the blood flow in a coronary artery is blocked for long enough that the heart muscle it supplies starts to die. In ST elevation myocardial infarction (STEMI), the vessel remains blocked, whereas in non-ST elevation myocardial infarction (NSTEMI) flow is spontaneously re-established so that ST elevation does not occur. The pathology for the 2 syndromes is the same but STEMI needs to be treated more urgently. Unstable angina is new onset angina (usually within 24 hours) or abrupt deterioration in previously stable angina, often occurring at rest.