The Chest Pain Challenge
Cardiovascular disease (CVD) is responsible for over 18.5 million deaths each year and costs the global economy over €500 billion. One of the most common manifestations of CVD is chest pain, which leads to an estimated 5% of all visits to the Emergency Department (ED) and around 25% of all ED admissions1.
Distinguishing patients with acute coronary syndrome (ACS) from within the very large overall proportion with suspected cardiac pain remains a major diagnostic challenge for clinicians, especially in individuals without clear symptoms or ECG features2.
Recent research estimates that at least 70% of all patients attending hospital with “chest pain, suspected cardiac” do not actually have a cardiac related condition – yet many of these (70-88%)3 are still admitted, often to a high level of cardiac care (e.g. Coronary Care Unit)4. Frequently, such patients are admitted as a precaution, because Acute Myocardial Infarction (AMI) could not be reliably ruled out by the ED. This reduces the risk of discharging patients from hospital with an unrecognised AMI (6%) and the potential medico-legal ramifications5. Patients with missed AMI also have a higher risk of a further adverse cardiac event6.
Although electrocardiogram (ECG) is the frontline diagnostic tool for the detection of AMI (e.g. ST changes), it lacks diagnostic sensitivity (~50%) and so cannot be solely relied upon to rule out AMI/ACS7.
The next line of investigation normally involves measuring cardiac biomarkers, traditionally focusing upon Troponin (TnI or TnT) and perhaps CK-MB. Unfortunately, these biomarkers are not typically elevated until at least 6-8 hours after chest pain onset, and so a period of observation in hospital is required for many patients, whilst clinicians wait for an adequately timed blood sample8.
In many cases, these patients stay longer than the initial 10-12 hours, frequently resulting in lengths of stay greater than 24 hours. Such prolonged stays are a frequent cause of hospital overcrowding, in addition to the potential complications that can be caused by a delayed patient diagnosis8.
The recent development of “high sensitivity” Troponin assays has led to an improvement in diagnostic sensitivity during the early hours after chest pain onset, compared to older Troponin assays9. However, recent guidelines demonstrate that it is still not possible to reliably rule out AMI based on a single early sample, and that serial sampling and “delta changes” are still required10. Furthermore, the improvement in sensitivity seems to be coupled by a reduction in specificity, and the potential challenges caused by positive Troponin results in the absence of ACS11.
Heart-type Fatty Acid-Binding Protein (H-FABP) is a biomarker of myocardial ischemia that can be used in conjunction with Troponin or hsTroponin to improve the early rule-out and rule-in of AMI/ACS, whether it be in the emergency department or cardiology ward, 12, read more.
H-FABP is now available as a routine laboratory reagent from Randox, meaning it does not require any dedicated instrumentation or equipment to run, and so can be easily introduced into routine clinical practice13, read more.What is H-FABP