Putting it all Together: Utility of LGE and Circumferential
Strain in Clinical Trials
With the understanding that LGE is a precursor to development of LVEF
abnormality and circumferential strain is abnormal before development of
LGE suggest that both are early indicator of DMD-CM. Circumferential
strain is a sensitive index of DMD-CM and can occur in young DMD
patients 54,
128. The combination of circumferential
strain and LGE can be a sensitive tool to detect occult cardiomyopathy
before LVEF abnormality is evident. This data along with preclinical
animal study demonstrating the impact of aldosterone inhibition in
cardiac function in mice was evident that we have a tool to assess
efficacy of therapy. We used CMR with LGE and circumferential strain as
endpoints in one of the first randomized, double-blinded
placebo-controlled trial in a cohort of DMD patients with known LGE but
relatively preserved LGE. The decline in circumferential strain
magnitude was lower in treatment compared to placebo group with stable
LGE. The studied concluded that in DMD patients the additional of an
aldosterone inhibitor (Eplerenone) to background afterload reducer
attenuated DMD-CM compared to placebo after 12 months of therapy129. A two-year
follow-up extension study in a smaller of DMD patients showed continued
attenuation of DMD-CM progression compared to an age-match group of
patients from an established CMR database130. The utility of
circumferential strain and LGE further validated in a follow-up
multi-center trial of aldosterone inhibition and demonstrated
attenuation of DMD-CM with no difference in circumferential strain
magnitude decline between the two therapy but less than reported in
patients on standard therapy in a multicenter double-blinded study82,
131.