Prognostic Value of LGE in Systemic Amyloidosis
What is the prognostic value of late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) in patients with established systemic amyloidosis and either known or suspected cardiac amyloidosis?
A systematic search of the medical literature was performed using several electronic databases. Primary studies were reviewed by two physicians, and studies were evaluated and data abstracted in accordance with MOOSE (Meta-analysis of Observational Studies in Epidemiology) and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies evaluating the prognostic importance of LGE on CMR with at least 12 months of follow-up data for a mortality endpoint were included. Data were integrated using a random-effects model. Data related to patients without biopsy-proven systemic amyloidosis were excluded.
Seven studies with a total of 425 patients were found. The majority of subjects (67%) were male. The average age was 64 years and average left ventricular ejection fraction (LVEF) was normal (59.2%). The vast majority (73%) of subjects had LGE, although there was variability across studies (28-84%). One hundred and forty-nine deaths occurred in 425 subjects over a mean follow-up duration of 25 months. The presence of LGE was associated with an odds ratio of 5.0 for death (95% confidence interval, 1.9-12.9; p = 0.0001). There was no significant heterogeneity between studies, and omission of any one study did not meaningfully change results. Mortality among patients without LGE was 7% per year compared to 25% per year in those with LGE (p = 0.001).
The authors concluded that presence of LGE in patients with systemic amyloidosis carries marked adverse prognosis for mortality.
This meta-analysis integrates the increasing literature supporting the use of this technique in clinical patients in whom cardiac amyloidosis is suspected. LGE CMR is now well established and widely available for this indication. Nonetheless, note should be made of the substantial methodologic variability in the underlying studies. This did not result in meaningful heterogeneity using meta-analytic methods. Nonetheless, several of the smaller studies did not find an association between LGE and mortality, perhaps related to power or advanced state of systemic illness in those populations. Imaging for cardiac amyloidosis remains an area of active advancement with novel CMR, echocardiographic, and nuclear methods emerging with increased sensitivity, availability, and ability to noninvasively differentiate forms of amyloid deposition.
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