麻豆传媒

Bringing handheld ultrasonography devices to the patient's bedside clinical assessment helped in diagnosing heart conditions, a meta-analysis indicated.

With transthoracic echocardiography as standard reference, diagnostic parameters of focused cardiac ultrasonography (FoCUS) were compared with those of standard point-of-care clinical assessment for the detection of:

• Left ventricular dysfunction (left ventricular ejection fraction less than 50%): sensitivity 84% and specificity 89% with FoCUS vs 43% and 81%, respectively, with clinical assessment

• Valvular disease of at least moderate severity: 71% and 94% for FoCUS vs 46% and 94% for clinical assessment

• Pericardial effusion: 98% and 95% for FoCUS vs 48% and 62% for clinical assessment

"These findings suggest that the addition of FoCUS to clinical assessment enables greater point-of-care detection of clinically important pathology that could otherwise be missed by routine clinical assessment," wrote Benjamin Hibbert, MD, PhD, of the University of Ottawa Heart Institute in Ontario, and colleagues in . "Thus, we provide further credence to the growing body of literature demonstrating that diagnostic yield improves when physicians incorporate FoCUS into their bedside patient evaluation."

But, the group cautioned,"FoCUS-assisted examination may help rule out cardiovascular pathology in some patients, but it may not be sufficient for definitive confirmation of cardiovascular disease suspected on physical examination."

The findings were based on nine studies from both inpatient and outpatient settings. Results for pericardial effusion came from just one study, however.

Handheld ultrasonography can yield structural detail of the heart, cardiac valves, and chambers; and it also provides information about cardiac function. Its advantages include the portability of devices, the absence of ionizing radiation, the relatively low cost, and the immediate results available.

"Despite these apparent advantages, the inherent pitfalls of FoCUS-augmented examination must be equally recognized," the investigators cautioned. "This technology, no matter how robust, is not a replacement for astute clinical judgment and adjudication of clinical information. Like the results of any diagnostic test, including physical examination, FoCUS results should be carefully interpreted in the context of pretest probability."

In general, the literature points to a better diagnostic yield for handheld ultrasound in finding regurgitant valve lesions than stenotic lesions, which can be partly attributed to the integration of color Doppler but not spectral Doppler in most FoCUS devices, noted Nir Flint, MD, and Robert Siegel, MD, both of Cedars-Sinai Medical Center in Los Angeles, in an .

Handheld ultrasonography has been addressed in guidelines from both the and the .

The nine studies included in the meta-analysis were all single-center, prospective studies with a median sample size of 84 participants. Average age among the studies was a median of 64 years.

Hibbert and colleagues acknowledged that the different reports they included came from variable clinical settings, and that skill levels were not uniform -- the people performing FoCUS ranged from medical students to attending physicians.

Another caveat was that most studies were judged to be at high or unclear risk of bias or applicability.

"These results support the role of FoCUS in ruling out clinically significant cardiovascular pathology in patients at low suspicion of disease; they also show the inability of FoCUS to provide definitive confirmation of cardiovascular disease strongly suspected on physical examination," the researchers nevertheless concluded.

Perhaps the addition of machine learning algorithms to this technology can improve accuracy, especially for novice users, Flint and Siegel suggested.

In the end, since "70% of echocardiograms in Medicare patients are ordered by noncardiologist providers, incorporating HHU [handheld ultrasonography] in the primary care setting could greatly improve downstream work-up and cost-effectiveness," according to the editorialists.