Echocardiographic screening for rheumatic heart disease (RHD) has the potential to detect subclinical cases for secondary prevention, but is constrained by inadequate human resources. Training non-expert health workers to perform focused cardiac ultrasound (FoCUS) may be a feasible strategy to enable mass screening. We aimed to investigate the inter-rater reliability and diagnostic accuracy of FoCUS performed by briefly-trained health workers.
Following an encouraging pilot study, we developed a highly-defined, eight-week training program in FoCUS for RHD. Trained nurses performed FoCUS on schoolchildren aged 5 to 15 years. An echocardiographer also performed a standard echocardiogram. A cardiologist reported all studies. The diagnostic accuracy of the index test (nurse measurement of valvular regurgitation) was compared to the reference standard (diagnosis by the cardiologist, based on the echocardiographer study). The assessment of the presence of regurgitation by the nurse and cardiologist was compared.
Seven nurses completed the training. 2004 children were enrolled. The diagnostic accuracy of the screening test (area under ROC curve) was 0.89 (95%CI, 0.83 – 0.94). The sensitivity and specificity at the primary cut-off were 84% and 86%. There was substantial agreement (κ=0.75) on the presence of regurgitation. Variation between nurse operators was noted.
Briefly-trained health workers can reliably assess the presence and extent of valvular regurgitation. The diagnostic accuracy of this screening method is high, and warrants further investigation. The diagnostic burden of screen-positive cases may present a challenge in many resource-limited settings. Quality assurance measures are important to ensure acceptable performance of all operators.