Development of a Test for Screening Reduced Blood Flow to the Heart

Introduction to Acute Coronary Syndrome

Recent research has initiated efforts to create a test aimed at screening for reduced blood flow to the heart. Acute coronary syndrome (ACS) encompasses various symptoms resulting from diminished or obstructed blood supply to the heart, including heart attacks and angina. Myocardial ischemia is the medical term for this condition, and it served as the focal point of a pilot study conducted at Duke University, USA.

Study Overview

This study, published in PLOS ONE, serves as a proof-of-concept to assess the viability of utilizing specific metabolites that exhibit distinct changes in individuals experiencing myocardial ischemia or arterial blockages induced by stress tests.

The Metabolic Activity of the Heart

Biomarkers for Risk Assessment

The heart functions as a metabolically active organ, and metabolite factors can serve as biomarkers for risk evaluation. Numerous studies have indicated that metabolomics profiling is effective in detecting early signs of arterial blockages or injuries associated with reduced blood supply to the heart. For instance, medium and long-chain acylcarnitines have been linked to an increased long-term risk of heart attacks.

Study Methodology

Participants in the study were patients from the emergency department who reported symptoms indicative of coronary disease. Blood tests and ECGs were conducted to eliminate individuals experiencing a heart attack or other conditions that would prevent them from undergoing stress tests. Blood samples were collected both before and two hours after the stress test.

Focus on Acylcarnitines

The Role of Acylcarnitines in Energy Metabolism

The researchers analyzed blood samples for acylcarnitines and amino acids, having established that these metabolites could potentially act as predictive biomarkers for ACS. Acylcarnitines are crucial compounds for the breakdown of fatty acids, a primary energy source. An accumulation of acylcarnitines due to incomplete fatty acid oxidation has been linked to various metabolic disorders, including type 2 diabetes, obesity, and cardiovascular diseases.

Findings on Metabolomic Profiling

The study identified five metabolites, including medium and long-chain acylcarnitines, which displayed altered levels in patients with myocardial ischemia compared to healthy individuals after stress tests. These findings provide a robust foundation for further research and align with other studies demonstrating that metabolomic profiling possesses sufficient discriminatory power for risk stratification in outpatients.

Implications and Future Research

Expert Insights

Dr. Limkakeng, the lead author of the study, stated in a press release, “Augmenting the imaging of a stress test with metabolite biomarkers could make that [screening for invasive procedures like catheterization] more accurate or more efficient.”

Need for Larger Studies

This pilot study included only 40 patients, highlighting the necessity for additional research with a larger cohort to verify whether the results are applicable to a broader population and to explore the potential of developing this method into a screening tool for emergency departments.

References

Limkakeng AT Jr, Henao R, Voora D, O’Connell T, Griffin M, Tsalik EL, Shah S, Woods CW, Ginsburg GS. Pilot study of myocardial ischemia-induced metabolomics changes in emergency department patients undergoing stress testing. PLoS One. 2019 Feb 1;14(2). Press release retrieved from https://www.eurekalert.org/pub_releases/2019-02/dumc-btf013019.php