Early cardiac magnetic resonance imaging in troponin-positive acute chest pain and non-obstructed coronary arteries

Abstract

Objective: We assessed the diagnostic and prognostic implications of early cardiac magnetic resonance (CMR), CMR-based deformation imaging and conventional risk factors in patients with troponin-positive acute chest pain and non-obstructed coronary arteries.

Methods: In total, 255 patients presenting between 2009 and 2019 with troponin-positive acute chest pain and non-obstructed coronary arteries who underwent CMR in ≤7 days were followed for a clinical endpoint of all-cause mortality. Cine movies, T2-weighted and late gadolinium-enhanced images were evaluated to establish a diagnosis of the underlying heart disease. Further CMR analysis, including left ventricular strain, was carried out.

Results: CMR (performed at a mean of 2.7 days) provided the diagnosis in 86% of patients (54% myocarditis, 22% myocardial infarction (MI) and 10% Takotsubo syndrome and myocardial contusion (n=1)). The 4-year mortality for a diagnosis of MI, myocarditis, Takotsubo and normal CMR patients was 10.2%, 1.6%, 27.3% and 0%, respectively. We found a strong association between CMR diagnosis and mortality (log-rank: 24, p<0.0001). Takotsubo and MI as the diagnosis, age, hypertension, diabetes, female sex, ejection fraction, stroke volume index and most of the investigated strain parameters were univariate predictors of mortality; however, in the multivariate analysis, only hypertension and circumferential mechanical dispersion measured by strain analysis were independent predictors of mortality.

Conclusions: CMR performed in the early phase establishes the proper diagnosis in patients with troponin-positive acute chest pain and non-obstructed coronary arteries and provides additional prognostic factors. This may indicate that CMR could play an additional role in risk stratification in this patient population.

Keywords: acute myocardial infarction; cardiac magnetic resonance (CMR) imaging; myocarditis.

Figure 1

Study flow chart. CMR, cardiovascular magnetic resonance.

Figure 2

The diagnostic impact of early CMR. Among patients with troponin-positive acute chest pain and non-obstructed coronary arteries, an early CMR (≤7 days) established a diagnosis in 86% of the patients. CMR confirmed the referral diagnosis in 48% and overrode it in 16%, identified the aetiology in 22%, revealed a structurally normal heart in 13% and remained Inconclusive in 1% of the patients. CMR, cardiovascular magnetic resonance.

Figure 3

CMR images of patients with myocardial infarction (A and D), myocarditis (B and E) and Takotsubo syndrome (C and F). CMR cine movie images depict endocardial contours during strain analysis (A–C). Late gadolinium-enhanced images showing transmural necrosis (white arrow) and microvascular obstruction (red arrow) in patients with acute myocardial infarction (D); patchy, midmyocardial necrosis in myocarditis (white arrows) (E); and the lack of LGE in Takotsubo syndrome (F). CMR, cardiovascular magnetic resonance; LGE, late gadolinium enhancement.

Figure 4

Kaplan-Meier curves showing the risk of mortality by CMR diagnosis. CMR, cardiovascular magnetic resonance.