Utility of cardiovascular magnetic resonance in patients with stable troponin elevation.

AIMS: Cardiovascular magnetic resonance (CMR) imaging has a potential role in the evaluation of symptomatic patients with stable troponin elevation; however, its utility remains unexplored. We sought to determine the incremental diagnostic value of CMR in this unique cohort and assess the long-term clinical outcomes. METHODS AND RESULTS: Two hundred twenty-five consecutive patients presenting with cardiac chest pain/dyspnoea, stable troponin elevation, and undergoing CMR assessment were identified retrospectively from registry database. The study cohort was prospectively followed for major adverse cardiac events (MACEs) (defined as composite of all-cause mortality and cardiovascular readmissions). The primary outcome measure was the diagnostic utility of CMR, i.e. percentage of patients for whom CMR identified the cause of stable troponin elevation. Secondary outcome measures included the incremental value of CMR and occurrence of MACE. CMR was able to identify the cause for stable troponin elevation in 160 (71%) patients. A normal CMR was identified in 17% and an inconclusive CMR in 12% of the patients. CMR changed the referral diagnosis in 59 (26%) patients. Utilizing a baseline prediction model (pre-CMR referral diagnosis), the net reclassification index was 0.11 and integrated discriminatory improvement index measured 0.33 following CMR. Over a median follow-up of 4.3 years (interquartile range 2.8-6.3), 72 (32%) patients experienced MACE. CONCLUSION: CMR identified a cause for stable troponin elevation in 7 of 10 cases, and a new diagnosis was evident in 1 of 4 cases. CMR improved the net reclassification of patients with stable troponin elevation.

Long-term clinical outcomes in patients with a working diagnosis of myocardial infarction with non-obstructed coronary arteries (MINOCA) assessed by cardiovascular magnetic resonance imaging.

BACKGROUND: Myocardial infarction with non-obstructed coronary arteries (MINOCA) is a distinct entity among patients presenting with troponin-positive acute chest pain. We have previously reported on the incremental diagnostic capability of cardiovascular magnetic resonance (CMR) in this cohort. There is paucity of evidence on the long-term (> 5 years) clinical outcomes of these patients as graded by their acute CMR diagnosis. METHODS AND RESULTS: A total of 229 patients with a working diagnosis of MINOCA who underwent CMR assessment during the acute admission (2010-2017) were prospectively studied. The primary endpoint was major adverse cardiac events (MACE) defined as a composite of all-cause mortality and cardiovascular readmissions, identified from hospital and primary care records. CMR performed at a median of 6 days (IQR 2, 8) from presentation provided a diagnosis in 85% of the patients (38% myocarditis, 28% acute myocardial infarction and 19% Takotsubo cardiomyopathy). Over a median follow-up of 7.1 years (IQR 3.7, 8.2), 56 (24%) patients experienced a MACE. We found a strong association between CMR diagnosis and MACE (log rank 30.47, p < 0.001). In multivariate analysis, age (hazard ratio = 1.07; 95% confidence interval = 1.05, 1.10; p < 0.001) and CMR diagnosis of acute myocardial infarction (hazard ratio = 8.87; 95% confidence interval = 2.58, 30.4; p = 0.001) were independent predictors of MACE. CONCLUSIONS: In a large cohort of patients with a working diagnosis of MINOCA, one in four suffer a MACE during long-term clinical follow-up. CMR diagnosis of acute myocardial infarction and age were significant predictors of MACE even in the absence of significant coronary artery obstruction.