A care pathway of high sensitivity troponin and MCG could eliminate the need for downstream testing and significantly reduce length of stay for patients presenting to the ED with chest pain.
in assessing intermediate risk patients who present to the ED with acute chest pain and improves both patient throughput and patient experience."
What
The goal of MAGNETO was to determine the usefulness of magnetocardiography (MCG) in diagnosing ischemia in intermediate risk patients presenting with acute chest pain in the ED. Results suggest MCG is anon-inferior, rapid, radiation-free alternative for assessing intermediate risk patients alongside high-sensitivity troponins with clear benefits to both patient throughput and patient experience.
Why
Despite their limited sensitivity and specificity, protracted duration, high costs, emission of radiation, and associated in convenience to patients, downstream tests - including exercise stress test, stress echo, and nuclear stress - are guideline recommendations and the standard of care for assessing intermediate risk chest patients presenting to the ED.
How
Chest pain patients with a HEART score ≥ 3 underwent MCG.MCG was compared to a standard of care of troponin and downstream non-invasive testing, with ischemia defined as ≥70% stenosis, index or within 30 days revascularization, or major adverse cardiac event (MACE) within 30 days.
Performance of MCG
Results indicated that MCG combined with troponin was non-inferior to troponin combined with exercise stress, stress echo, or nuclear stress testing.
When examining the concordance between MCG and downstream testing in the 70patients who underwent both, MCG identified 2 additional cases of ischemia that were missed by nuclear stress tests. Importantly, there were also 0 cases of ischemia identified by downstream testing that were missed by MCG.
Reduction in Length of Stay (LOS)
In our current healthcare landscape, where the emergency department is characterized by limited resources, overcrowding, and increased admission into observation status, an important benefit of the MCG pathway is its potential impact on utilization of resources and length of stay for patients.
The MCG pathway demonstrated a substantially shorter time to test (TTT) of 2.95hours compared to 22.9 hours for stress testing and 22.7 hours for echocardiography.
Patient Experience & Preference for MCG
Patients who underwent both a stress and an MCG scan were asked to rate their diagnostic experience using a 5-point system across four key items:
- Total time spent
- Comfort during the test
- Recovery after the test
- Overall experience
Patient satisfaction scores serve as a key administrative benchmark in healthcare. When comparing the overall satisfaction scores between MCG and Stress testing, MCG yielded significantly higher patient satisfaction across all four evaluated categories.
Objectives
For enrolled patients presenting with chest pain or anginal equivalents in the emergency department, we investigated the effectiveness of using MCG in combination with troponin compared to non-invasive downstream testing methods, including:
- Graded exercise testing (GXT)
- Stress echocardiogram
- Nuclear stress
Patient Population
The MAGNETO trial enrolled 390 patients from the emergency department (ED) presenting with suspected acute coronary syndrome (ACS) between January 2021 and October 2022.
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Study Mechanics
MCG scans were performed on all eligible patients using CardioFlux MCG, a 36-magnetometer system produced by Genetesis. The 90-second scans were performed at rest without any need for ionizing radiation, contrast agents, beta blockers, or vasodilators.
Treating physicians were blinded to the MCG scan results, which were independently evaluated for ischemia offline by three separate physicians - two emergency room physicians and one cardiologist - who were also blinded to all patient data.