Peak troponin and early CMR guides management in suspected ACS and nonobstructive coronary arteries

UK: Early cardiac magnetic resonance (CMR) in patients with suspected myocardial infarction and non-obstructive coronary arteries (MINOCA) is associated with high diagnostic yield (94%), especially among patients with a greater degree of myocardial injury suggests an article published in JACC Journals: Cardiovascular Imaging. 

Patients presenting with acute coronary syndrome( ACS) and nonobstructive coronary arteries are a diagnostic dilemma. CMR, cardiac magnetic resonance (CMR) imaging is a valuable, non-invasive diagnostic tool, which has an overall diagnostic yield of 75%; however, in 25% of patients, it does not identify any myocardial injury. Cardiac troponin T, a biochemical marker for the diagnosis of myocardial infarction, when elevated indicates the presence of, but not the underlying reason for, myocardial injury. Identifying the underlying etiology is necessary to ensure appropriate patient management and prognosis.

This cohort study was conducted by Matthew G.L. Williams, University of Bristol, UK, and colleagues to assess whether diagnostic yield would increase when utilizing both CMR and peak troponin levels in 719 patients with suspected myocardial infarction and nonobstructive coronary arteries (MINOCA) without obvious cause.

Consecutive patients with ACS and nonobstructive coronary arteries without an obvious cause underwent CMR. The primary endpoint of the study was the diagnostic yield of CMR. The Youden index was used to find the optimal diagnostic cut point for peak troponin T to combine with CMR to improve diagnostic yield. Logistic or Cox regression models were used to estimate predictors of a diagnosis by CMR. The peak troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Overall, CMR has a diagnostic yield of 74%.

Study results indicated,

• CMR performed <14 days from the presentation and with a peak troponin of ≥211 ng/ lead to an improved diagnostic yield of 94% compared with 72% when performed ≥14 days.

• CMR performed <14 days and with a peak troponin of <211 ng/L, lead to the diagnostic yield of 76% compared with 53% when performed ≥14 days.

• The odds of a CMR being diagnostic increased by 20% for every 1-decile increase in the peak troponin level (OR, 1.20).

The author and colleagues concluded that the combination of CMR performed within 14 days from the presentation and peak troponin T ≥211 ng/L leads to a very high diagnostic yield and it remains high even when CMR is performed 14 days or longer after the presentation, but reduces when peak troponin is T<211 ng/L.

Reference:

Matthew G.L. Williams, Kate Liang, Estefania De Garate, Lucrezia Spagnoli, Emiliano Fiori, Amardeep Dastidar, Umberto Benedetto, Giovanni Biglino, Thomas W. Johnson, Thomas Luscher, Chiara Bucciarelli-Ducci   JACC: Cardiovascular Imaging, 2022,

https://doi.org/10.1016/j.jcmg.2022.03.017