Can gastrointestinal bleeding after heart attack be predicted?

Knowing which patients are at higher risk of bleeding complications following a heart attack can help health professionals to take preventative measures. Now researchers at Karolinska have published a list of eight key primary factors that increase the risk of gastrointestinal bleeding.

While some of these had previously been identified, the study used machine learning techniques to pinpoint additional predictors, such as smoking, blood pressure and blood glucose levels. The findings are reported in the European Heart Journal – Cardiovascular Pharmacotherapy.

Bleeding in the upper gastrointestinal (GI) tract is one of the most common bleeding complications following acute myocardial infarction. The condition is resource intensive for hospitals, causes considerable suffering and increases the risk of death. Bleeding complications also limit the use of anti-thrombotics, which in turn can worsen the cardiovascular prognosis.

A sharper focus on bleeding complications over the past two decades has led to several strategies for reducing the risk of upper gastrointestinal tract bleeding. Despite this, there are few studies on this complication that include a diverse population of heart attack patients.

‘If we can identify patients at high risk of upper gastrointestinal bleeding following heart attack, doctors will be able to take prophylactic measures to mitigate this risk,’ says the study’s corresponding author Moa Simonsson, ‘There are, for instance, drugs that combat bleeding complications, gut bacteria tests that can be used on risk groups and other possibilities for personalised treatment for heart attack patients at high risk of bleeding complications.’

The study is based on data on almost 150,000 patients with acute myocardial infarction between 2007 and 2016 from the national SWEDEHEART registry. Of these patients, approximately 1.5 percent suffered GI bleeding within a year of their heart attack. They also had an increased risk of death and stroke.

The researchers confirmed several known factors that increase the risk of upper GI tract bleeding, including low levels of haemoglobin (a protein that helps to transport oxygen in the blood), previous upper GI tract bleeding, age and intensive antithrombotic treatment.

Using an algorithm, they also identified new risk factors, including smoking, blood pressure, blood glucose and previous treatment for stomach disorders, such as ulcers and acid reflux.

‘If you combine traditional statistical models with machine learning methods, you can create unique opportunities to find key risk factors for previously unknown cardiovascular events,’ says co-author Philip Sarajlic, ‘This makes it possible for us to make effective use of valuable data from the medical quality registry by taking account of complex relationships between risk factors and outcomes in order to further optimise the current recommendations for patient care.’

The researchers are set to launch a major clinical study in the coming months to investigate the significance of diagnosis and treatment of a common infection in the upper GI tract. ‘A pilot study last year showed a two-fold increase in the presence of Helicobacter pylori in heart attack patients,’ says Robin Hofmann, researcher and consultant at Karolinska Institutet’s Department of Clinical Science and Education, Södersjukhuset.

‘We will now proceed with a large, randomised study to ascertain whether a systematic screening of heart attack patients for Hp infection and, where relevant, its treatment, can reduce bleeding complications and improve prognosis after heart attack.’