CMR findings in newly diagnosed patients with sarcoidosis and elevated troponin and NT-proBNP levels

Background

Cardiac involvement in sarcoidosis is frequently underrecognized, yet it represents a major determinant of prognosis. Cardiac magnetic resonance (CMR) provides comprehensive tissue characterization and functional assessment, while circulating biomarkers such as cardiac troponin and N-terminal pro–B-type natriuretic peptide (NT-proBNP) may reflect myocardial injury and hemodynamic stress.

Materials and methods

The study included 50 consecutive patients with newly diagnosed systemic sarcoidosis. All patients underwent standardized CMR imaging, including cine imaging for functional assessment, late gadolinium enhancement (LGE), and parametric mapping to evaluate the presence of inflammation, focal and diffuse fibrosis. Serum cardiac troponin and NT-proBNP levels were obtained within a short interval of CMR examination. Patients were stratified into two groups according to the presence or absence of elevated cardiac biomarkers. CMR findings were compared between groups to assess the relationship between myocardial involvement and biomarker elevation.

Results

Of the 50 patients included, 18 (36%) had elevated cardiac troponin and/or NT-proBNP levels. Late gadolinium enhancement (LGE) was significantly more frequent in patients with elevated biomarkers compared with those with normal levels (72% vs. 21%, p < 0.001). Left ventricular ejection fraction was significantly lower in the biomarker-positive group (52.3 ± 7.8% vs. 61.9 ± 5.6%, p < 0.001).

Global myocardial T2 relaxation times were significantly higher in patients with elevated biomarkers (56.4 ± 3.1 ms vs. 52.1 ± 2.4 ms, p < 0.001), indicating increased myocardial inflammation. Similarly, extracellular volume fraction (ECV) was significantly increased in the biomarker-positive group (27.8 ± 3.5% vs. 25.1 ± 2.8%, p < 0.001), consistent with diffuse myocardial involvement. On multivariable logistic regression analysis, the presence of LGE (odds ratio [OR] 5.9, 95% confidence interval [CI] 1.9–18.4, p = 0.002), increased global T2 time (OR per 1 ms increase 1.4, 95% CI 1.1–1.8, p = 0.006), and reduced ejection fraction (OR per 5% decrease 1.7, 95% CI 1.1–2.6, p = 0.01) were independently associated with elevated cardiac biomarkers.

Conclusions

In patients with newly diagnosed sarcoidosis, elevated troponin and NT-proBNP levels are associated with more extensive myocardial involvement on CMR. The combined assessment of cardiac biomarkers and multiparametric CMR may improve early detection and risk stratification of cardiac sarcoidosis, even at the time of initial diagnosis.