Echocardiography useful in detecting PH, predicting its course
But it's unlikely in near future to replace more invasive diagnostic test
Echocardiography, a noninvasive imaging method to examine heart structure and function, can be useful in making a preliminary diagnosis of pulmonary hypertension and in determining its likely course, according to a review study.
“In future, it is important to use multiple echocardiographic parameters for detection and predicting the prognosis of PH,” the researchers wrote, noting that it is more convenient than the current way of establishing a PH diagnosis.
The study, “Diagnostic and prognostic value of echocardiography in pulmonary hypertension: an umbrella review of systematic reviews and meta-analyses,” was published in the journal BMC Pulmonary Medicine.
Echocardiography often is used when pulmonary hypertension is suspected
PH is characterized by high blood pressure in the pulmonary arteries, the blood vessels that supply the lungs. As a result, the right side of the heart has to work harder to pump blood through the lungs, risking heart failure later in life.
Right heart catheterization, which involves inserting a catheter into the right ventricle and pulmonary artery, is “the gold standard” for diagnosing PH as it directly measures pulmonary artery pressure. But it is invasive, the researchers noted, and difficult to widely use in clinical practice.
In contrast, echocardiography is “non-invasive, convenient, and accurate,” they added. It’s also widely used to determine the probability of PH, by assessing systolic pulmonary arterial pressure (sPAP) combined with other symptoms. Echocardiography uses sound waves to create a moving image of the heart; sPAP indicates how much pressure the blood is exerting against the pulmonary artery walls when the heart contracts.
Echocardiography’s effectiveness in establishing a PH diagnosis and likely prognosis, however, remains controversial.
Researchers in China conducted an umbrella review to assess existing evidence on the use of echocardiography in the disease.
An umbrella review looks at evidence from systematic reviews to help summarize available data. In this case, the researchers included 13 meta-analyses, nine on PH diagnosis and four on prognosis. Meta-analysis are statistical analysis of data obtained from several studies.
Nine meta-analyses published between 2010 and 2022 reported the sensitivity and specificity of echocardiography for PH diagnosis, with the number of included studies ranging from six to 29. Sensitivity refers to a test’s ability to correctly identify people with a certain condition, whereas specificity refers to its ability to identify those without the condition.
While invasive, right heart catheterization needed to confirm a PH diagnosis
These studies reported that sPAP had a high sensitivity (up to 0.88, maximum is 1) although relatively low specificity, whereas right ventricular outflow tract acceleration time had both high sensitivity and specificity (84%).
Right ventricular outflow tract acceleration time refers to the interval between blood being pumped out from the right ventricle to peak blood flow velocity across the pulmonary valve (which manages blood flow from the right ventricle to the pulmonary artery). This parameter strongly correlates with sPAP.
“Nevertheless, [right heart catheterization] remains necessary for accurate confirmation of the diagnosis,” the researchers wrote.
In determining the disease’s likely course, pericardial effusion, right atrial area, and tricuspid annulus systolic displacement were of prognostic value for people with pulmonary arterial hypertension (PAH), a type of PH.
Pericardial effusion is the buildup of fluid in the space around the heart, which can put pressure on the heart, preventing it from pumping normally. Tricuspid annulus systolic displacement refers to the displacement of the tricuspid valve, located between the right upper and lower chambers of the heart, during a contraction. Right atrial area is the area of the upper right chamber of the heart.
In addition, right ventricular longitudinal strain (RVLS), a measure of right ventricle dysfunction, showed independent value in predicting PH outcomes. A higher RVLS was associated with a nearly three times higher risk of a poorer disease course.
“We are confident that RVLS will provide incremental prognostic value to echocardiography or risk stratification models in the future,” the researchers wrote.
Overall, review findings indicate that echocardiography can aid in the clinical diagnosis of PH and estimations of a patient’s prognosis, the scientists noted. Future research should focus on constructing models with various parameters to increase this exam’s value with PH.
Among the study’s limitations were a reliance on the quality of the included meta-analyses, the scientists noted. Also, patients in those studies all initially had suspected PH based on clinical indications and echocardiography. “As a result, the sensitivity and specificity of echocardiography in our study may have been inflated,” they wrote.
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