Outcomes of borderline rheumatic heart disease: A prospective cohort study.

Context And Aims: The advent of systematic screening for rheumatic heart disease (RHD) by echocardiography in endemic regions has led to a new entity: borderline RHD. The pathogenicity and natural history of borderline RHD needs to be addressed. The aim of this study was to assess the outcomes of children detected by echocardiography as having borderline RHD.

Methods: Schoolchildren in 4th grade (i.e., aged 9-10years) who were prospectively echo-screened for RHD (2012-2014) in Nouméa, New Caledonia, were asked to participate. Children with borderline RHD according to consistent independent review by two cardiologists were included and followed-up in 2015.

Results: Among the 8684 schoolchildren screened, 49 were diagnosed with borderline RHD according to the Cardiologist clinically involved in the child's management plan. After independent review by two cardiologists, 25 children were consistently diagnosed with borderline RHD and included in the follow-up study. Overall, inter-observer agreement was moderate with diagnostic kappa values of 0.63 (95% CI 0.45-0.78). After a median follow-up of 23months (IQR (20.5-33.0), 15 children (60.0%) had stability of valvular lesions, 8 (32.0%) had normal findings according to the WHF criteria. Two children (8.0%) had definite RHD on the follow-up echocardiogram, but no clinical events or audible pathological murmur during the study period. No factor could be identified as prognostic of either stability or progression.

Conclusions: Borderline RHD diagnosed by systematic screening in high-risk populations remains mostly unchanged at 2years follow-up. Diagnosis of borderline RHD may require two reviewers for consistency.