PT  - JOURNAL ARTICLE
AU  - Luke David Hunter
AU  - Mark Monaghan
AU  - Guy Lloyd
AU  - Carl Lombard
AU  - Alfonso Jan Kemp Pecoraro
AU  - Anton Frans Doubell
AU  - Philipus George Herbst
TI  - Interscallop separations of the posterior mitral valve leaflet: a solution to the ‘borderline RHD’ conundrum?
AID  - 10.1136/openhrt-2020-001452
DP  - 2020 Nov 01
TA  - Open Heart
PG  - e001452
VI  - 7
IP  - 2
4099  - http://openheart.bmj.com/content/7/2/e001452.short
4100  - http://openheart.bmj.com/content/7/2/e001452.full
SO  - Open Heart2020 Nov 01; 7
AB  - Objective The World Heart Federation (WHF) criteria incorporate a Doppler-based system to differentiate between ‘physiological’ and ‘pathological’ mitral regurgitation (MR)—a sole criterion sufficient for the diagnosis of WHF ‘borderline’ rheumatic heart disease (RHD). We have identified that interscallop separations (ISS) of the posterior mitral valve (MV) leaflet, can give rise to pathological MR in an otherwise-normal MV. We aimed to establish and compare the prevalence of ISS-related MR among South African children at high and low risk for RHD.Methods A prospective cross-sectional echocardiographic study of 759 school children (aged 13–18) was performed. Cases with MR≥1.5 cm underwent a second comprehensive study to determine the prevalence of RHD according to the WHF guideline and establish the underlying mechanism of MR.Results Of 400 high-risk children, two met criteria for ‘definite RHD’ (5 per 1000 (95% CI 1.4 to 18.0); p=0.5) and 11 for ‘borderline RHD’ (27.5 per 1000 (95% CI 15.4 to 48.6)). Of 359 low-risk children, 14 met criteria for borderline RHD (39 per 1000 (95% CI 23.4 to 64.4)). Comprehensive echocardiography identified an underlying ISS as the mechanism of isolated pathological MR in 10 (83.3%) high-risk children and 11 low-risk children (78.5%; p>0.99).Conclusions ISS are a ubiquitous finding among South African schoolchildren from all risk profiles and are regularly identified as the underlying mechanism of WHF pathological MR in borderline RHD cases. A detailed MV assessment with an emphasis on ascertaining the underlying mechanism of dysfunction could reduce the reported numbers of screened cases misclassified as borderline RHD.