Advanced Cardiac MRI for Evaluating Myocardial Fibrosis and Hypertrophy in Patients with Aortic Coarctation

Background: Aortic coarctation (CoA) necessitates long-term monitoring to identify late complications, including restenosis, aneurysms, and heart failure. Nonetheless, there remains a lack of understanding regarding the adverse remodeling of left ventricular (LV) tissue, which leads to these complications.

Methods: Extracellular volume fraction (ECV), native T1, and intracellular water lifetime were measured from pre- and post-gadolinium contrast T1 measurements in 46 patients with CoA and ten age-matched controls. Normalized LV volume, mass, and ejection fraction were obtained from cine CMR. Patients’ CoA was classified as LG (“low grade” = Vmax ≤3 m/s and no restenosis nor arterial hypertension or medication), HG (“high grade” = Vmax >3 m/s or one of LG’s other variables applies), and BAV “CoA with bicuspid aortic valve (BAV).”

Results: ECV was significantly higher in the HG group (0.31 ± 0.01) compared with the LG group (0.26 ± 0.02, p = 0.013) and healthy controls (0.26 ± 0.01, p = 0.0045). Group with BAV (0.31 ± 0.05) showed a higher ECV than LG without statistical significance (p = 0.059). Native T1 values were significantly elevated in the HG group (T1 = 1,391 ± 162 ms) compared with the LG group (T1 = 1,213 ± 47 ms, p = 0.008), and in the Group with BAV (T1 = 1,390 ± 127 ms) compared with the LG group (p < 0.001). Intracellular water lifetime was lower in the LG group (0.24 ± 0.03 s) compared with the HG group (0.28 ± 0.04 s) and the Group with BAV (0.31 ± 0.05 s) but did not reach statistical significance (p = 0.24). Patients on blood pressure medication showed a significantly lower native T1 (p = 0.016) and intracellular water lifetime (p = 0.034) compared with patients without BP medication.

Conclusion: Patients with higher disease severity of CoA demonstrated elevated ECV compared with low-grade CoAs and healthy controls, reflecting adverse tissue remodeling. Interestingly, patients with LG-CoA but concomitant BAV showed significantly greater diffuse myocardial fibrosis than isolated LG-CoAs. These findings imply that CoA patients, especially those with concomitant BAV, could be at increased long-term risk for complications potentially related to diffuse myocardial fibrosis, such as diastolic dysfunction and arrhythmias. The antihypertensive medication shows positive effects and may decrease the degree of myocardial fibrosis and hypertrophy in CoA patients.

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Artikel online veröffentlicht:
11. Februar 2025