Heart disease is the biggest killer of women and men globally
Although cardiac biomarkers have come far, there is still no rapid and objective diagnostic tool to rapidly and effectively triage 1 of 3 who present to the emergency department with chest pain as they fall into a grey-zone with existing troponin assays.
Many of these patients are at heightened risk of heart attack due to unstable angina.
Physicians are demanding diagnostic tools to help further triage these patients to enable rapid and accurate decision making.
What is unstable angina?
Unstable Angina is a condition in which the heart receives insufficient oxygenated blood at rest to meet its demands. It is a form of cardiac ischemia that does not result in death of the heart tissue. It is often a sign that a patient is at risk of an imminent heart attack; a heart attack is an extreme and sustained form of cardiac ischemia where the lack of oxygen results in death of heart tissue.
A key symptom of unstable angina is chest pain. It is usually caused by a reduction of blood flow to the heart muscle, generally due to coronary artery disease, which is a build-up of plaque in the arteries supplying blood to the heart.
Coronary artery disease is by a considerable margin the leading cause of death globally, representing 18% of global deaths or 10m per annum.
Managing coronary artery disease costs the US over $200b per annum, putting a high load on the healthcare system, especially emergency doctors who are on the frontline.
KOLs in cardiology and emergency physicians confirm an unmet need for a rapid and accurate method to diagnose unstable angina patients allowing immediate medical treatment; from those that can be safely sent home.
Diagnosis of Heart Attack Risk
Triage process of chest pain
A patient presenting with chest pain activates a process to rule out those without cardiac disease to identify those that should be admitted with suspected heart attack or unstable angina — collectively referred to as “Acute Coronary Syndrome” (ACS).
In the US alone, each year
8 million
present to hospitals with chest pain
4 million
(50%) can be ruled out from having ACS using troponin, plus patient history and ECG, leaving 4 million to be further triaged.
1.6 million
(20%) will have elevated troponin levels and will be admitted or held for observation, of which 1 in 2 (~700,000) will have had a heart attack. Troponin is a market of USD2b per annum.
2.4 million
(30%) in the troponin grey zone, of which up to 1 in 4 have unstable angina, however there are no rapid diagnostics to further triage this group to effectively identify those individuals.
Marker C aims to identify patients with unstable angina.
Diagnosis of unstable angina
While existing troponin tests can be used to determine who has had a heart attack, they are not useful at detecting unstable angina. Assessments for unstable angina made by ED physicians using their current tool-kit can therefore be inaccurate, which can result in:
Unnecessary invasive testing
It is now widely accepted that invasive testing carries substantial risks and therefore should not be performed unless absolutely required.
Due to a lack of biomarker for unstable angina, physicians are forced to act conservatively and unnecessarily hold and refer many of those patients with suspected unstable angina to receive invasive testing in order to decide who gets further treatment.
This means 3 out of 4 people are held for observation or admitted unnecessarily for suspected unstable angina, leading to unnecessary monitoring and/or cardiac catheterization costing US$5k-15k per patient and up to 3 hospitalisation days.
A marker of unstable angina could determine which patients should be referred to invasive testing and those which are safe to go home. This approach would then free up hospital resources to enable those with unstable angina to be prioritised for invasive testing.
Delayed decision making
Chest pain patients presenting to the ED with unstable angina can develop a heart attack in the hours or days after their initial presentation to the ED.
A marker of unstable angina could enable physicians to rapidly order an intervention before a heart attack occurs.
Through the triaging of patients, this approach would then free up hospital resources to enable those with unstable angina to be prioritised for invasive testing.
Inappropriate discharge
A missed diagnosis results in less effective treatment.
Marker C could help avoid sending patients home with unstable angina that could develop into MI and help prioritise patients to receive invasive tests and treatment.
Health systems are overloaded
Hospitals and physicians in the US are each paid a flat fee for assessing patients in the ER.
While there are additional payments for holding a patient in observation for patient for 24 hours, payments are disproportionately low compared to the cost of a hospital bed.
Due to this there are significant economic pressures by a hospital on physicians to admit or discharge patients as rapidly as possible.
Hospitals and ER clinicians are unable to overcome this by indiscriminately admitting patients.
If patients are recklessly discharged who subsequently have a cardiac event, ER clinicians are at risk of litigation, and ER clinicians and hospitals risk their reputation.
The design of the US reimbursement system can be in conflict with the best interests of patients. A biomarker for unstable angina could help physicians make rapid and objective decisions.
Transforming cardiovascular healthcare
Biomarker diagnostics for rapidly identifying imminent heart attack
