Handheld Echocardiographic Screening for Rheumatic Heart Disease by Nonexperts
What is the efficacy of nonexpert echocardiography screening using a handheld echocardiographic device (HHE) for identification of rheumatic heart disease (RHD) in children?
Two nurses with prior experience in HHE received additional training including one-on-one supervision by a skilled physician echocardiographer in the use of HHE to identify evidence of RHD. For HHE, the protocol included two-dimensional echo and color Doppler in the parasternal long-axis and apical four- and five-chamber views with a total of 11-13 recorded images per examination. For each HHE, simplified rheumatic HD diagnostic criteria were established, which included mitral regurgitation (MR) with a MR jet ≤1.5 cm in any view or aortic regurgitation (AR) present in any view. Results of nonexpert HHE were compared to results of standard full service echocardiography (FSE) performed by an experienced physician echocardiographer. For FSE, the complete World Health Federation criteria for diagnosis of RHD were used and patients were categorized as either having definite or borderline evidence for RHD.
For HHE, the average duration of the patient encounter was 6.69 minutes with 4.97 minutes required in acquisition of echocardiographic imaging. Matched HHE and FSE studies were available in 956 subjects who ranged in age from 15-17 years (11.1 ± 2.5 years), 56% of whom were female. By FSE, 913 children (95.5%) were classified as normal, 32 (3.3%) as borderline RHD, and 11 (1.2%) as definite RHD. In the majority of cases (86%) diagnosed with RHD, isolated mitral valve disease was noted with 14% having mixed mitral and aortic involvement. There were no cases of mitral or aortic stenosis noted. The sensitivity and specificity of HHE performed by nonexpert examiners were 74.4% and 78.8% for detection of borderline or definite RHD. When only definite RHD was considered, sensitivity rose to 90.9%. There was nonagreement between HHE and FSE in 205 studies (29%); 95% of the nonagreement was the result of HHE positive studies, which were negative by FSE. False-positive HHE was predominately due to measurement of erroneous color jets rather than true MR/AR. Only 11 of 205 discrepant studies were the result of negative HHE in the presence of FSE diagnostic of RHD.
HHE performed by nonexpert echocardiographers might provide a financially feasible method for widespread screening of RHD.
This is one of several studies that demonstrated the feasibility of simplified echocardiographic screening using handheld devices for the detection of unrecognized RHD in populations at greater risk of the disease than typically encountered in the United States. This study does demonstrate the concordance using the simplified echocardiographic platform and protocol as well as simplified criteria compared to the standard WHO criteria for diagnosis of RHD. The sensitivity and specificity of 74.4% and 78.8%, while not ideal, does result in appropriate detection of the majority of affected subjects. The majority of false results were related to inappropriate measurement of color Doppler signals, which did not represent true MR or AR. Whether an expert observer using the identical device and algorithms would have avoided these errors was not addressed in this study.
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