Pediatric Track Session
SCMR 22nd Annual Scientific Sessions
Cystic fibrosis (CF), the most common lethal autosomal recessive disease in Caucasian populations, is a multisystem disease characterised by inflammation and fibrosis. Pulmonary infections and respiratory failure are the main causes of death. Forced expiratory volume in 1 second (FEV1) is the most important prognostic factor.
Whilst cor pulmonale is well described, myocardial expression of the cystic fibrosis transmembrane conductance regulator (CFTR) together with observed impairment of systolic and diastolic function, have raised the possibility of a defective ion channel-induced CF cardiomyopathy. As life expectancy increases, characterising CF cardiac involvement and understanding the pathophysiological manifestations of CFTR mutations in myocardium are important in terms of patient survival, quality of life and transplant candidacy.
In the first study to do so, we evaluated myocardial involvement in CF using multiparametric CMR.
Ten CF patients (aged 28 years [25-36]) underwent 1.5T CMR during an acute lung exacerbation (11 days from admission) and in the convalescent period (85 days from admission). Twelve healthy volunteers (aged 37 years [27-45]), provided control data. CMR included myocardial cines, T1 mapping, extracellular volume fraction (ECV), late gadolinium enhancement (LGE) and dynamic contrast enhanced MRI, which provided K trans, an assessment of capillary permeability.
Acutely exacerbating CF patients had significantly larger LV and RV end systolic volumes and significantly lower ejection fractions (EF) compared to healthy controls. EF normalised in the convalescent period. ECV was elevated in CF patients compared to healthy controls during an acute exacerbation and, whilst it improved, remained elevated in the convalescent period. Nine (90%) CF patients demonstrated non-ischaemic LGE. (Table. 1)
Acute CF exacerbations were associated with a significant drop in LV EF and non-significant increases in ECV and K trans. (Table. 2, Figure. 1A)
In CF patients, ECV showed a strong inverse correlation with FEV1 (rho=-0.704, p=0.002) (Figure. 1B). K trans showed a moderate inverse correlation with FEV1 (rho=-0.461, p=0.047).
In the first CMR study of CF patients, CF was found to have a primary effect in the myocardium. Acute CF exacerbations are associated with evidence of myocardial oedema, impaired LV function and a suggestion of increased myocardial capillary leak. Whilst myocardial ECV improves in the convalescent period, it remains elevated, suggesting that chronic stable CF is associated with myocardial fibrosis. Furthermore, myocardial ECV, known to associate strongly with adverse outcome, showed a strong inverse correlation with FEV1.