Abstract
Background: Rheumatic heart disease (RHD) rates remain high in many socially disadvantaged populations. Early detection through active case finding is resource intensive and task-sharing with cardiac sonographers may improve access to screening. The accuracy of cardiac sonographers in the echocardiographic evaluation of RHD has not previously been assessed. The 2012 World Heart Federation guidelines were used to compare agreement, inter-rater reliability, and accuracy between cardiac sonographers and cardiologists in the echocardiographic evaluation of RHD.
Method: Four paediatric cardiologists and seven cardiac sonographers underwent structured training before independently reporting the same 210 echocardiograms (a total of 2,310 individual studies). Participants were blind to the results of other assessors and blind to the original diagnoses by a three-person expert panel consensus. Median results from each group of professionals were compared to each other and the original diagnosis. Individual results were also analysed to determine agreement with the original panel diagnosis using Cohen's kappa. Inter-rater agreement for multiple assessors in each group was determined using Fleiss' kappa. Sensitivity, specificity, and likelihood ratios were estimated using the original panel diagnosis as the reference standard.
Results: The agreement was substantial between median cardiac sonographer and median cardiologist results for the detection of any abnormality (k=0.74, 95% CI 0.61-0.88); any RHD (k=0.79, 95% CI 0.65-0.92); and definite RHD (k=0.78, 95% CI 0.64-0.91). Accuracy for the detection of any RHD was high with sensitivity of median cardiologist results of 79% (95% CI 71%-86%) and specificity of 97% (95% CI 87%-99%) and median sonographer sensitivity was 83% (95% CI 75%-89%) with specificity of 93% (95% CI 85%-98%).
Conclusions: Expert cardiac sonographers achieved a similar level of agreement, inter-rater reliability, and accuracy to expert cardiologists in the reporting of RHD. These findings support the use of task-sharing for the echocardiographic detection of RHD.