Are “minor” heart attacks really minor?

Heart attacks are usually caused by a blockage in an artery supplying blood to the heart, but it isn’t always a complete blockage. Heart attacks caused by partial artery blockages are called NSTEMI (non-ST-elevation myocardial infarction - named for the way they show up on an ECG scan). They are the most common type of heart attack in the UK, but in the past they have been considered “minor” and doctors weren’t sure whether they needed the same type of treatment as more “major” heart attacks.

The problem was that very little was known about how well people fared after having NSTEMI, so it was hard to decide if the current treatment was appropriate.

Developing a risk score

BHF Professor Keith Fox and colleagues at the University of Edinburgh decided to tackle this problem by tracking NSTEMI patients over a number of years. They established the largest international database of patients admitted with chest pain, called the Global Registry of Acute Coronary Events (GRACE). From 1999 to 2009, it was used to track what happened to 100,000 patients with heart-related chest pain from nearly 250 hospitals in 30 countries.

The registry revealed that many people who had an NSTEMI heart attack were at high risk of having another, potentially more serious, heart attack later in life.

To stop high-risk patients from slipping through the net, Professor Fox and his team created a scoring system – the GRACE risk score - to help doctors identify which patients with NSTEMI would benefit from more intensive treatments. The GRACE risk score has been updated, and is still in use today, including as a smartphone app, helping doctors make decisions about treatment for people with chest pain swiftly and accurately.

Finding out which patients to treat urgently

Professor Fox also led a clinical trial to find out how urgently clinicians should treat people admitted with NSTEMI. At the time, doctors were unsure if these patients needed an urgent angiogram (a type of X-ray of their heart arteries), or whether they should wait to see if medication could work first. The BHF-funded trial, called RITA-3, showed conclusively that people with NSTEMI should have an early coronary angiogram, which then gives the option of unblocking the artery at the same time if that is found to be needed.

The results of RITA-3 changed treatment guidelines in the UK, Europe and USA. It is now recommended that high-risk NSTEMI heart attack patients are offered an angiogram, and any appropriate follow-on treatments, within 72 hours of getting to hospital. This research has made a huge difference to the care of millions of people with coronary heart disease.

First published 1st June 2021