Haemodynamic evaluation of Coarctation of Aorta using Phase-Contrast MRI and its comparison with Echocardiographic findings.

Abstract

BACKGROUND:  Haemodynamic assessment of COA constitutes a vital aspect in the pre-operative assessment algorithm of COA. Moreover, assessment of collaterals and better delineation of associated anomalies/findings using MRI aids in the exact mapping of this condition.     

OBJECTIVES: Measurement of the pressure gradients, using Phase-Contrast MRI and assessment of associated cardiac lesions / valvular affections in patients with coarctation of aorta and mapping of collaterals, with subsequent comparison of MRI findings with echocardiographic findings.

PARTICIPANTS: Patients with findings of/suspicious of COA on the echocardiographic assessment.

STUDY DESIGN: Prospective observational study.

METHODS: The study cohort comprised of 20 successive patients with coarctation of aorta who were assessed via  echocardiography and cardiac-MRI between July 2018 to July 2020. Subsequently, findings were compared with the criterion standardized by MTD/ CCA/operative findings (where ever available).

RESULTS: Twenty patients twelve were males (60 percent) and eight were females (40 percent) with a mean age of 17yrs (range from 0.019-60 years). The site of coarctation of aorta was accurately delineated in 85% of cases by Echo and in 100% of cases by MRI. Mild, moderate, and severe coarctation of aorta was detected in 10%,25%, and 55% of patients respectively. Significant collateralization was detected in 55% of severe and 60% of moderate cases of coarctation of aorta with a moderate level of agreement between echocardiography and cardiac -MRI findings (kappa value of 0.459) and Pearson's correlation coefficient of 0.823. ASD, VSD, PDA, BAV, LVH, and PAH was detected in 9%,16%,10%,10%,29%, and 26% of cases.

CONCLUSION: PC-MRI constitutes an important diagnostic modality for assessment of aortic coarctation complementing and extending the findings of echocardiography. Furthermore, aortic arch measurements using MRI are comparable with the anatomic measurements, especially to delineate related tubular hypoplasia. Besides the severity of coarctation of aorta, MRI can aid in the evaluation of collateral circulation and better delineation of associated anomalies which constitutes a corner-stone in pre-operative evaluation algorithm in cases of COA particularly in paediatric age group.

IMPLICATION: PC-MRI constitutes a vital diagnostic modality in the pre-operative assessment algorithm of COA with good agreement between PC-MRI and Echocardiographic findings.

KEYWORDS: COA: Coarctation of Aorta, MRI: Magnetic Resonance Imaging, PC-MRI: Phase Contrast Magnetic Resonance Imaging, MTD: Multi-team discussion, CCA: Cardiac Catheter Angiography.