Cardiovascular magnetic resonance accurately detects obstructive coronary artery disease in suspected non-ST elevation myocardial infarction: a sub-analysis of the CARMENTA Trial

Abstract

Background: Invasive coronary angiography (ICA) is still the reference test in suspected non-ST elevation myocardial infarction (NSTEMI), although a substantial number of patients do not have obstructive coronary artery disease (CAD). Early cardiovascular magnetic resonance (CMR) may be a useful gatekeeper for ICA in this setting. The main objective was to investigate the accuracy of CMR to detect obstructive CAD in NSTEMI.

Methods: This study is a sub-analysis of a randomized controlled trial investigating whether a non-invasive imaging-first strategy safely reduced the number of ICA compared to routine clinical care in suspected NSTEMI (acute chest pain, non-diagnostic electrocardiogram, high sensitivity troponin T > 14 ng/L), and included 51 patients who underwent CMR prior to ICA. A stepwise approach was used to assess the diagnostic accuracy of CMR to detect (1) obstructive CAD (diameter stenosis ≥ 70% by ICA) and (2) an adjudicated final diagnosis of acute coronary syndrome (ACS). First, in all patients the combination of cine, T2-weighted and late gadolinium enhancement (LGE) imaging was evaluated for the presence of abnormalities consistent with a coronary etiology in any sequence. Hereafter and only when the scan was normal or equivocal, adenosine stress-perfusion CMR was added.

Results: Of 51 patients included (63 ± 10 years, 51% male), 34 (67%) had obstructive CAD by ICA. The sensitivity, specificity and overall accuracy of the first step to diagnose obstructive CAD were 79%, 71% and 77%, respectively. Additional vasodilator stress-perfusion CMR was performed in 19 patients and combined with step one resulted in an overall sensitivity of 97%, specificity of 65% and accuracy of 86%. Of the remaining 17 patients with non-obstructive CAD, 4 (24%) had evidence for a myocardial infarction on LGE, explaining the modest specificity. The sensitivity, specificity and overall accuracy to diagnose ACS (n = 43) were 88%, 88% and 88%, respectively.

Conclusion: CMR accurately detects obstructive CAD and ACS in suspected NSTEMI. Non-obstructive CAD is common with CMR still identifying an infarction in almost one-quarter of patients. CMR should be considered as an early diagnostic approach in suspected NSTEMI.

Trial registration: The CARMENTA trial has been registered at ClinicalTrials.gov with identifier NCT01559467.

Keywords: Acute coronary syndrome; Cardiovascular magnetic resonance; Coronary angiography; Coronary artery disease; Diagnostic accuracy; High-sensitivity cardiac troponin; Non-ST elevation myocardial infarction.

Fig. 1

Patient flowchart. A stepwise analysis was used to investigate the diagnostic accuracy of cardiovascular magnetic resonance (CMR) to detect CAD (≥ 70% stenosis in any epicardial coronary artery). Green boxes: correct positive or negative results; orange boxes: false-positive or -negative results. Abbreviations: CAD coronary artery disease; LGE late gadolinium enhancement; ICA invasive coronary angiography; NSTEMI non-ST elevation myocardial infarction

Fig. 2

Patient example. Upper row: basal-inferior-inferoseptal edema on T2-weighted short axis left ventricular image (a arrowheads), 50–75% transmural basal-inferior-inferoseptal myocardial infarction with microvascular obstruction (b arrowheads). Lower row: total occlusion of the mid right coronary artery (c arrowhead), 71–90% mid left anterior descending artery stenosis (d arrowhead) with collaterals to right coronary artery (d asterisk)

Fig. 3

Patient example. a: adenosine stress-perfusion scan showing 50% transmural mid-anterior-anteroseptal perfusion defect (arrowheads). b: > 90% stenosis in the mid left anterior descending artery (arrowhead)

Fig. 4

Patient example. a: limited subendocardial mid-inferior myocardial infarction (arrowhead). b: normal coronary angiogram, only right coronary artery shown

Fig. 5

Graphical abstract. Panel a: stepwise CMR analysis, step 2 only performed in patients with normal or equivocal findings after step 1. Panel b: diagnostic accuracy of CMR to detect obstructive CAD (≥ 70% stenosis in any epicardial coronary artery) and acute coronary syndrome (ACS). Panel c: adjudicated diagnosis by independent committee, based on clinical data, CMR and invasive coronary angiography. Abbreviations: CAD coronary artery disease; CMR cardiovascular magnetic resonance imaging; NSTEMI non-ST elevation myocardial infarction