Handheld echocardiography beats auscultation for detecting rheumatic heart disease

By Will Boggs MD

Handheld echocardiography is superior to auscultation for detecting rheumatic heart disease (RHD), which may make it a cost-effective screening strategy in developing countries.

"Echocardiographic screening has emerged as a powerful tool for early RHD detection," said Dr. Justin Godown from Monroe Carell Jr. Children's Hospital at Vanderbilt in Nashville, Tennessee.

"Emerging data indicate that it may be the most cost-effective strategy for controlling RHD in low-resource settings. However, to make echocardiographic screening an affordable, practical, and sustainable public health solution, we need to validate less expensive equipment (handheld echocardiography) and the use of a non-physician healthcare workforce," Dr. Godown told Reuters Health by email.

Dr. Godown and colleagues investigated the incremental value of handheld echocardiography over auscultation to identify RHD in a study of 1,317 children aged five to 17 years who attended five different schools in Gulu, Uganda. All participants also underwent standard portable echocardiography (which is more costly than handheld echocardiography).

With standard portable echocardiography as the diagnostic standard, handheld echocardiography was 97.8% sensitive and 87.3% specific for detecting definite RHD and 78.4% sensitive and 87.3% specific for detecting definite or borderline RHD.

By comparison, auscultation was only 22.2% sensitive for detecting definite RHD and 16.4% sensitive for detecting definite or borderline RHD, the researchers report in Pediatrics, online March 23. Its specificity was comparable to that of handheld echocardiography.

Based on the 1.1% prevalence of definite RHD and 4.0% prevalence of borderline or definite RHD, 123 children would require handheld echocardiography screening to diagnose one additional case of definite RHD and 41 children would require such screening to detect one additional case of borderline or definite RHD, compared with auscultation.

The negative predictive value of handheld echocardiography for definite RHD exceeded 99% regardless of disease prevalence. The positive predictive value of the handheld screen was 7.2% for definite RHD, and 2.5% with auscultation.

"This approach is only applicable in endemic regions where the prevalence of disease is high, as it was in Gulu (2-4%)," Dr. Godown said. "RHD screening with any type of machine is less applicable in the developed world where the prevalence of RHD is much lower; the rate of false positive studies would be too high. However, there may be pockets of RHD even within developed countries, such as the Aboriginal population in Australia."

"Our group is currently investigating implementation of handheld echocardiography performed by nurses with prior ultrasound experience who then undergo a limited handheld RHD training program," Dr. Godown said. "The results are promising and will be presented at the upcoming American Society of Echocardiography meeting in Boston this June. Development of standardized, validated training protocols for non-physicians is certainly a high priority for future investigations."

"This paper and others demonstrate that auscultation is not an effective screening tool for early RHD," Dr. Godown concluded. "With the development of lower-cost ultrasound technology, the potential for cost-effective screening and limitation of progression by penicillin prophylaxis is becoming a very real possibility."

Dr. Brandon Wiley from Mount Sinai Medical Center, New York, who recently reviewed the use of handheld ultrasound to diagnose cardiovascular disease at the bedside, said, "Handheld echocardiography (HAND) is a cost-effective, portable screening tool with a high specificity that can be used to rule-out the presence of disease. Thus HAND can be used to screen large cohorts to identify those with potential pathology that can then undergo definitive evaluation with more expensive technology (STAND)."

"Not unlike the stethoscope, the use of HAND is operator dependent and those with more experience or training do a better job acquiring and interpreting the data these devices yield," Dr. Wiley said. "Thus, although HAND possesses immense potential for the screening of possible cardiac pathology, the need for specific training and imaging protocols is required for safe and accurate implementation of this technology."

"HAND is a powerful diagnostic tool that has the potential to improve the diagnostic accuracy of the traditional 'bedside' exam for the presence of cardiac pathology," Dr. Wiley concluded.

The Vscan handheld ultrasound from General Electric used in the study retails for $7,900, compared with $17,600 for GE's Vivid i, one of the standard portable ultrasounds used in the study.

SOURCE: http://bit.ly/19XQmHL

Pediatrics 2015.

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