It’s not often that medicine signals a big change in how it perceives an established disease phenomenon. Yet, that is precisely what a recent publication, The Lancet Commission on Rethinking Coronary Artery Disease, sets out to do.
Coronary heart disease has traditionally been diagnosed when there is an inadequate blood supply to the heart muscle. This ischaemic episode occurs when there is a blockage in one or more of the coronary arteries. The blockage is caused by a progressive build-up of atherosclerosis in the walls of the coronary artery. It can cause angina, or in more severe cases may proceed to a full-blown heart attack. This understanding of coronary artery disease led to a focus on finding out how much of a blockage (stenosis) a person has.
The diagnostic test for stenosis is an angiogram, in which dye is introduced into the coronary arteries by a cardiologist and the patency or otherwise of the vessel is recorded on a screen. In particular, the percentage stenosis in each artery is recorded. The subsequent clinical pathway often involves using a balloon to push the blockage back against the arterial wall and then placing a stent where the block had been to keep the artery open.
As well as preventing future blockages, this procedure (called an angioplasty) could sometimes reverse a heart attack as it was happening.
‘Forget about glamour’: Jonathan Anderson offers advice to would-be fashion designers as he receives TCD honour
Death of Pope Francis: Derek Mooney leads RTÉ’s coverage to intermittently jaw-dropping effect
Chob Thai restaurant, Clontarf: The most memorable thing here is the bill
Careless People: The controversial book is shocking and reveals Facebook is far worse than we could have suspected
This was an exciting time in cardiology, as it meant some patients could avoid having open-heart surgery. But it very much focused on the presence and percentage of a stenosis as being the fundamental problem in coronary heart disease. Reversing the stenosis became the major aim of treatment.
[ Heart attacks in women: ‘I really had no idea I was having one’Opens in new window ]
What the Lancet commission – after two years’ work – sets out to do is to move the focus from this late manifestation of coronary artery disease to an earlier stage which sees the beginning of the blockage as worthy of more attention. Blockages in coronary arteries are caused by atherosclerosis in which a fatty material called atheroma builds up inside the walls of the artery. Atheroma is also referred to as plaque.
A commentary accompanying the publication of the Lancet Commission on Rethinking Coronary Artery Disease outlines the problem clearly: “Despite the understanding that clinicians should consider atheroma itself rather than its late manifestations as the primary mediator of adverse events, decades-old dogma made it difficult to move the clinical paradigm away from primarily identifying and fixing stenotic vessels to modifying atheroma as the central preventive and treatment strategy.”
The authors say what is needed is to introduce a more rational approach by shifting the emphasis from ischaemia to atheroma. “The Commission highlights this important change by reclassifying coronary artery disease as atherosclerotic coronary artery disease (ACAD); this relatively simple but crucial change proposes to identify and modify the underlying disease (atherosclerosis) rather than only find and treat flow-limiting disease ...”
The case history of a colleague suggests some change is already under way. Some 20 years ago he was admitted to coronary care with chest pain. A subsequent angiogram showed a 90 per cent blockage of one coronary artery, which was stented. Some 10 years later he required two further stents in different arteries. Just recently, he had another angiogram, which showed a less than 50 per cent block in one artery- the others were disease free. This time he didn’t have a stent inserted, as it was felt that his long-term treatment with statins, aspirin and other cardiac medication would continue to modify his ACAD progression.
In addition the latest research suggests that continuing medical treatment would have the same benefit – in preventing a future heart attack – as placing a stent in the affected artery. This case illustrates just one step in the direction the Lancet Commission is advocating.
But the ultimate rewards would be significant: a complete shift in thinking around atherosclerotic coronary artery disease could, according to research, save up to 8.7 million lives annually.
