(P152) APPROACH, REPORTING, AND YIELD OF CLINICAL SCREENING PRACTICES IN PATIENTS WITH NON-ISCHEMIC CARDIOMYOPATHY: A SYSTEMATIC REVIEW

Background: Up to one third of patients with unexplained non-ischemic cardiomyopathy (NICM) have a familial pattern of inheritance and one third have a disease-causing variant in a gene encoding a cardiac structural or functional protein. The phenotype is characterized by regional or global left ventricular systolic dysfunction, either with dilatation (termed dilated cardiomyopathy; DCM) or without (termed non-dilated left ventricular cardiomyopathy).
Cascade screening helps to identify at risk family members but the approach in published studies lacks standardization and has not previously been systemtically evaluated.

METHODS AND RESULTS: We conducted a systematic literature review to examine the approach, timing intervals, imaging modalities, reporting, and yield of clinical screening practices to identify at-risk relatives after a diagnosis of NICM in a family member. Medline was searched from 1946 to April 2023, limited to adult humans and English language.

Seventeen studies were included in the review and included 3963 unique patients. A quadrilateral diagnostic approach combining clinical examination, family history, electrocardiogram, and echocardiography was used in most studies (Table 1). Family history was collected by interview or medical record review in 13 studies.. Only 2 studies used a standardized family history questionnaire. Definitions of ‘familial’ NICM varied with “one or more relatives with NICM” being the most common criteria in 11 studies. Similarly, among the 17 studies 13 definitions of DCM were used, most combining measurements of left ventricular end-diastolic diameter (often >112% of age and body surface area) and function (typically LVEF < 45-50%). 1001 (25%) of proband cases met the clinical criteria for familial NICM/DCM. 456 (8%, range: 2-26) of relatives that were screened had newly identified cases of NICM/DCM. 254 (6%) relatives had pre-established NICM/DCM at screening. Four studies that included longitudinal follow-up ranging from 10 months to 10 years yielded a further 62 (3%) positive NICM/DCM cases.

Conclusion: There is heterogeneity in the definition of familial and dilated cardiomyopathy. Screening practices vary significantly including differences of interval frequency, duration of followup, modalities, reporting and yield of the screening methods. This highlights the need for standardization and guidelines for family screening.