A leading UK doctor says a pioneering test using advanced computer modelling has the potential to “re-define” the way coronary heart disease is diagnosed and managed.
The technology, known as fractional flow reserve computed tomography (FFRCT), developed by US company HeartFlow, creates a detailed 3D model of a patient’s coronary arteries from a standard CT scan image.
It then uses complex calculations to work out the extent of blockages in the coronary arteries and if they are restricting the flow of blood – all without the need for invasive intervention.
Professor Nick Curzen, a consultant cardiologist at Southampton General Hospital, said the system could become the “default method” for the initial assessment of patients with chest pain after he presented a study that showed it changed treatment plans in more than a third of cases.
Coronary heart disease, also known as coronary artery disease, develops when a build up of fatty substances silts up or blocks the blood supply to the heart. It is the most common cause of angina – chest pain – and heart attacks and is responsible for 73,000 deaths in the UK every year.
Currently, most patients presenting with angina end up having an angiogram, in which thin plastic tubes are passed from an artery in the wrist to the heart so that dye can be injected down the coronary arteries under an X-ray camera.
The most accurate way to decide if a narrowing seen during an angiogram is restricting blood flow through an artery is to use a fine wire in which a pressure transducer is mounted to assess the drop in pressure across the narrowing, known as fractional flow reserve (FFR).
The FFR gives a precise reading of whether or not blood flow is significantly restricted, which is vital in deciding if a patient can be treated with medical therapy or if they require a stent or surgery.
However, in a study presented at the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) congress, Prof Curzen and his colleagues found that using the novel computer technology added “significant” detail to standard CT scans of patients who presented with angina.
This enabled the clinicians to make improvements in diagnosis and management without the use of an invasive angiogram X-ray and pressure wire.
The data resulted in changes to 36% of management plans for stable heart disease patients – a similar outcome to a previous study which looked at the additional benefits of pressure wire testing in patients having an angiogram.
“It is already well established that measuring FFR from within the body when taking angiograms can improve management decisions for patients with chest pain, but we are now moving into exciting new territory where we can discover important and accurate details without intervention,” said Prof Curzen, who is also a professor of interventional cardiology at the University of Southampton.
“This study demonstrates that the non-invasive FFRCT analysis from a standard coronary CT scan has the potential to become the default method for the initial assessment of many patients with cardiac-sounding chest pain by assessing both the coronary anatomy and physiology simultaneously.
"This has important implications for our clinical practice and could re-define conventional care pathways.”
John Stevens, chairman and CEO of HeartFlow, said: “This analysis has an unmatched level of accuracy in determining, non-invasively, whether a lesion is restricting blood flow to the heart and this study demonstrates the profound impact the technology can have in directing patient care.”
Posted on Wednesday 12 August 2015