Screening for subclinical rheumatic heart disease: addressing borderline disease in a real-world setting

Luke D Hunter; Alfonso J K Pecoraro; Anton F Doubell; Mark J Monaghan; Guy W Lloyd; Carl J Lombard; Philip G Herbst

doi:10.1093/ehjopen/oeab041

Screening for subclinical rheumatic heart disease: addressing borderline disease in a real-world setting

Eur Heart J Open. 2021 Dec 27;1(3):oeab041. doi: 10.1093/ehjopen/oeab041. eCollection 2021 Nov.

Authors

Luke D Hunter¹, Alfonso J K Pecoraro¹, Anton F Doubell¹, Mark J Monaghan², Guy W Lloyd^{3

4

5}, Carl J Lombard⁶, Philip G Herbst¹

Affiliations

¹ Division of Cardiology, Department of Medicine, Faculty of Medicine and Health Sciences, University of Stellenbosch and Tygerberg Academic Hospital, Francie van Zijl Drive, Tygerberg, 7505, Cape Town, South Africa.
² Department of Cardiology, King's College Hospital, Denmark Hill, London, SE5 9RS, United Kingdom.
³ Echocardiography Laboratory, Barts Heart Centre, St Bartholomew's Hospital,West Smithfield, London EC1A 7BE, United Kingdom.
⁴ Institute of Cardiovascular Sciences, University College London, 62 Huntley St,WC1E 6DD, London, United Kingdom.
⁵ William Harvey Research Institute Barts & The London School of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, United Kingdom.
⁶ Division of Epidemiology and Biostatistics, Department of Global Health Faculty of Medicine and Health Sciences, Stellenbosch University, Francie van Zijl Drive, Tygerberg, Cape Town,7505, South Africa; and.

Abstract

Aims: The World Heart Federation (WHF) criteria identify a large borderline rheumatic heart disease (RHD) category that has hampered the implementation of population-based screening. Inter-scallop separations (ISS) of the posterior mitral valve leaflet, a recently described normal variant of the mitral valve, appears to be an important cause of mild mitral regurgitation (MR) leading to misclassification of cases as WHF 'borderline RHD'. This study aims to report the findings of the Echo in Africa project, a large-scale RHD screening project in South Africa and determine what proportion of borderline cases would be re-classified as normal if there were a systematic identification of ISS-related MR.

Methods and results: A prospective cross-sectional study of underserved secondary schools in the Western Cape was conducted. Participants underwent a screening study with a handheld (HH) ultrasound device. Children with an abnormal HH study were re-evaluated with a portable laptop echocardiography machine. A mechanistic evaluation was applied in cases with isolated WHF 'pathological' MR (WHF 'borderline RHD'). A total of 5255 participants (mean age 15± years) were screened. A total of 3439 (65.8%) were female. Forty-nine cases of WHF 'definite RHD' [9.1 cases/1000 (95% confidence interval, CI, 6.8-12.1 cases/1000)] and 104 cases of WHF 'borderline RHD' [19.5 cases/1000 (95% CI, 16.0-23.7 cases/1000)] were identified. Inter-scallop separations-related MR was the underlying mechanism of MR in 48/68 cases classified as WHF 'borderline RHD' with isolated WHF 'pathological' MR (70.5%).

Conclusion: In a real-world, large-scale screening project, the adoption of a mechanistic evaluation based on the systematic identification of ISS-related MR markedly reduced the number of WHF 'screen-positive' cases misclassified as WHF 'borderline RHD'. Implementing strategies that reduce this misclassification could reduce the cost- and labour burden on large-scale RHD screening programmes.

Keywords: Rheumatic heart disease; Screening echocardiography.