Hand-Held Cardiac Ultrasound Screening by Family Doctors
What is the utility of handheld echocardiography (HHE) performed by primary care physicians (PCPs) in locations remote from referral centers, but with web-based backup by expert echocardiographers (EEs)?
Fourteen PCPs underwent training in HHE, which included 28 hours of lecture and 4 days of hands-on scanning. Parasternal long- and short-axis views, four-chamber apical view, and subcostal views were acquired. Color Doppler was utilized for assessment of valvular regurgitation. PCPs were instructed to target the HHE exam to left ventricular (LV) systolic dysfunction, LV hypertrophy, left atrial enlargement, anatomical valve abnormalities, valvular regurgitation (dichotomized as mild or moderate to severe), aortic root and ascending aorta size, pericardial effusion, inferior vena cava dilation, and aortic enlargement. After HHE, 8-12 loops were uploaded to a web program for subsequent review by the EE and the interpretation relayed to the PCP for further decision making. This study was performed in 1,312 consecutive patients from three remote PCP sites, and all patients had symptoms or physical exam evidence suggestive of cardiovascular disease.
Based on clinical examination, PCPs anticipated performance of full-service echocardiography in 859 patients (group A). In 453 patients (group B), HHE was performed only to complement the physical exam. After remote expert interpretation, full-service echocardiography was eventually requested by the PCP in only 276 (30.1%) patients, and discharges without further evaluation increased by 10.2%. In group B, 32 patients (7%) were identified as having significant cardiac disease. Of the 1,312 HHEs, image quality was considered good in 35.4%, acceptable in 45.4%, and poor in 19.2% by the expert interpreter, and inconclusive in 115 cases (8.7%). Overall diagnosis by PCP and EE was concorded in 761 patients (58%). Two hundred seventy-four studies were considered normal by PCPs, only two of which were noted to have significant disease by the expert reader.
HHE performed at the time of service by PCP with backup of a remote web-based expert interpretation potentially provides a rapid incremental screening tool for cardiovascular disease, which may decrease resource utilization.
Small portable HHE devices have been in use for approximately a decade. Previous studies have demonstrated a degree of utility when utilized by non-echocardiographers including PCPs, physician extenders, and medical house officers typically when used for targeted purposes such as assessment of LV systolic function, pericardial effusion, and overall volume status. In more remote regions where rheumatic heart disease is prevalent, they have shown utility for screening for occult rheumatic valvular heart disease when utilized by physician extenders. In this study, investigators employed remote expert reading of a limited number of echocardiographic images acquired by PCPs using a handheld device. Agreement was generally good for presence of a normal heart and detection of severe abnormalities, and the majority of studies deemed normal or showing only mild abnormalities did not have severe relevant abnormalities when reviewed by an expert interpreter. This study is unique among others evaluating HHE in that remote expert interpretation of the acquired images was available after which decision making regarding established diagnosis, the need for full-service echocardiography or the appropriateness of patient discharge was reassessed and demonstrated a decrease in more expensive full-service resource utilization. Of note, the accuracy of the PCP for detecting abnormalities and the agreement between experts and PCPs did not significantly increase over the time course of this study, suggesting that intrinsic limitations in the HHE imaging platforms may result in a plateau of clinical efficacy when used by non-echocardiographers.
Keywords: Aortic Valve Insufficiency, Diagnostic Imaging, Echocardiography, Heart Valve Diseases, Hypertrophy, Left Ventricular, Internet, Pericardial Effusion, Physicians, Primary Care, Referral and Consultation, Rheumatic Heart Disease, Treatment Outcome, Vena Cava, Inferior, Ultrasonography, Doppler
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