Idiopathic Dilated Cardiomyopathy Diagnosis and Late Gadolinium Enhancement CMR

Among patients with dilated cardiomyopathy (DCM) and late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) data available in the Dilated Cardiomyopathy Precision Medicine Study cohort, the clinical diagnostic criteria used in that study correctly classified ischemic and nonischemic causes of DCM, according to research findings published in Circulation: Heart Failure.

Identifying myocardial scar and its cause with LGE-CMR has been recently considered for patients with idiopathic DCM. In the DCM Precision Medicine Study (ClinicalTrials.gov identifier: NCT03037632), researchers sought to assess the cause of DCM and investigate LGE patterns for possible prior ischemic events in an effort to validate the diagnostic criteria the study used.

To accomplish this, they conducted a retrospective evaluation of the DCM Precision Medicine multi-site consortium study. This included 1204 idiopathic DCM patients, of whom 396 had prior CMR examination, 327 (mean aged 46 years; 53.2% men; 55.4% White) had LGE imaging. Idiopathic DCM was defined as the exclusion of all other clinically detectable causes of DCM, except genetic. These patients exhibited tobacco use (40.4%), obesity (48.3%), high cholesterol (23.9%), hypertension (46.2%), and diabetes (17.4%). Among these patients, 178 showed LGE, of whom 156 had LGE consistent with idiopathic DCM.

In prior studies, LGE has identified replacement fibrosis from causes including prior heart attack.  Proposed LGE patterns were created to assign cause as ischemic or nonischemic. An ischemic-pattern of LGE was recognized in 22 (6.7%) of the 327 patients in this study.

Study limitations included the underpowered sample size, the fact that actual CMR images were not reviewed, and the heterogeneity of image acquisition protocols and interpretation.

The researchers concluded, “This study validated the clinical diagnostic criteria used in the DCM Precision Medicine Study, demonstrating its accuracy in classification of ischemic and nonischemic causes of DCM.”

Reference

Haas GJ, Zareba KM, Ni H, Bello-Pardo E, Huggins GS, Hershberger RE. Validating an idiopathic dilated cardiomyopathy diagnosis using cardiovascular magnetic resonance: The Dilated Cardiomyopathy Precision Medicine Study. Circ Heart Fail. Published online March 4, 2022. doi:10.1161/CIRCHEARTFAILURE.121.008877