An international study has found that patients with coronary heart disease (CHD) who undergo invasive interventions (stents or surgery) don’t do any better than patients who take medications only.
The ISCHEMIA trial, as the study was called, recruited over 5000 patients across 37 countries, and the results could fundamentally change the way patients with CHD are managed.
What is coronary heart disease?
Coronary heart disease (CHD), also known as ischaemic heart disease, is a major cause of death in the UK and worldwide.
It is a disease caused by the build-up of fatty deposits in the walls of the arteries that supply blood to the heart (coronary arteries). Over time the arteries become narrowed because of the build-up and not enough blood is delivered to the heart (ischemia). This may cause chest discomfort during physical activity (angina).
Depending on the level of damage in the heart most patients are offered one of two invasive procedures, either a stent which opens up the clogged arteries, or coronary bypass surgery, which helps divert blood and improve blood flow.
A smaller proportion of patients, especially those who have milder forms of CHD, are given medication only.
Where it began
In 2007 a large randomised trial was conducted in North America on patients with CHD which compared those who were given stents and those given medication only.
The study, called the COURAGE trial, found that those with milder forms of CHD did no better on invasive procedures compared to medication only.
However, because the study allowed patients with only mild ischemia, it was argued that the results were not necessarily true for moderate or severe CHD patients.
The ISCHEMIA study
In 2012, New York University Grossman School of Medicine’s Professor Judith Hochman and Stanford University’s Professor David Maron led the ISCHEMIA study sponsored by the National Heart, Lung, and Blood Institute (NHLBI) in the USA, focusing on moderate to severe CHD.
Professor Roxy Senior (pictured), senior cardiologist at Royal Brompton & Harefield NHS Foundation Trust and director of cardiac research at Northwick Park Hospital, was chosen to lead the ISCHEMIA trial in the UK.
He managed to recruit 27 centres across the country to participate in the trial, which led to the UK becoming the third largest recruiter for the trial globally, behind only India and the USA.
A large part of this was also thanks to the collaboration between Northwick Park Hospital and our Trust.
“For this study it was important that we had the recruiting expertise of Northwick Park Hospital (the second largest recruiting site in the world) where GP’s routinely refer patients directly to the chest pain clinic, and Royal Brompton Hospital, where all CT scans and cardiac surgery took place.” Said Professor Senior.
For the ISCHEMIA trial, patients with moderate to severe CHD were recruited to participate. CT scans were taken to ensure they had the correct diagnoses, as well as to rule out very high-risk patients, which is about 9% of this patient group.
The eligible participants were then randomly assigned into one of two groups. One group were offered optimal medical therapy and the usual invasive procedures (a stent or coronary bypass) and the second group were offered optimal medication therapy only.
The researchers then determined the increased or decreased likelihood of a number of important indicators between the two groups, including hospitalisation for heart failure and unstable chest pain, heart attack, cardiac arrest and death.
They found that routine invasive therapy in CHD patients failed to reduce the likelihood of the major adverse events compared to the CHD patients given medication therapy only. However, the study did find that invasive therapy was better in improving quality of life in terms of disabling chest pain.
What do these results mean for CHD patients?
Professor Senior hopes that the results will be used to help inform guidelines on CHD treatment.
“If the guidelines are updated it will fundamentally change how patients with CHD are treated. Instead of offering CHD patients invasive treatments from the start, they could instead be given medical therapy first, with invasive procedures only offered to those with ongoing severe symptoms.” He said.
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