Focused Cardiac Ultrasound to Detect LV Dysfunction and Valvular Heart Disease
How does focused cardiac ultrasound (FoCUS) perform in comparison to clinical assessment alone for diagnosis of left ventricular (LV) systolic dysfunction and valvular heart disease?
This was a systematic review and meta-analysis of studies reporting the diagnostic accuracy of FoCUS-assisted clinical assessment versus clinical assessment alone. Only studies comparing FoCUS to a standard of two-dimensional echocardiography with Doppler, performed by a trained cardiologist or sonographer and interpreted by a board-certified echocardiographer, were included.
All nine studies that met inclusion criteria were single-center, prospective cohort studies. Only one study was clinic-based; all others included inpatients only. Median sample size was 84 participants, and median patient age was 64 years. FoCUS examinations were performed by professionals and trainees of various backgrounds: cardiologists (two studies), intensivists (one study), cardiac sonographers (two studies), hospitalists (one study), and medical students (three studies). All studies but one were judged to be at high or unclear risk of bias or applicability. The sensitivity of clinical assessment for LV systolic dysfunction was 43% (95% confidence interval, 33-54%), whereas that of FoCUS-assisted examination was 84% (95% CI, 74-91%). Specificity of clinical assessment for LV systolic dysfunction was 81% (95% CI, 65-90%), while that of FoCUS-assisted examination was 89% (95% CI, 85-91%). For aortic and mitral valve disease of at least moderate degree, clinical assessment alone had a sensitivity of 46% (95% CI, 35-58%), compared with 71% (95% CI, 63-79%) for FoCUS-assisted examination. Specificity for these valve lesions was 94% for both examination alone and FoCUS-assisted examination (95% CI, 91-96%).
FoCUS-assisted examination is more sensitive than clinical examination alone for LV systolic dysfunction and aortic or mitral valve disease of moderate or greater severity, with no significant difference in specificity for these conditions.
Ultrasound is an extremely operator-dependent technique, and the quality of FoCUS examinations in this study likely varied based on operator experience level, equipment quality, time constraints, and patient positioning. One unanswered question, which is always challenging to answer in cardiac imaging studies, is whether FoCUS had a significant impact on clinical management. Identification of previously unrecognized LV dysfunction or major valvular dysfunction may alter a patient’s long-term management plan, but may not affect the short-term plan immediately following hospital admission. Therefore, in hospitalized patients who go on to have complete transthoracic echocardiograms, the additive value of FoCUS remains uncertain. Notably, this study did not explore the use of FoCUS in resource-poor settings, where comprehensive cardiac imaging services are not available.
Keywords: Diagnostic Imaging, Echocardiography, Echocardiography, Doppler, Heart Failure, Heart Valve Diseases, Hospitalists, Inpatients, Mitral Valve, Students, Medical, Ultrasonography, Ventricular Dysfunction, Left
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