Right heart catheterization ‘central’ to pediatric PAH care, despite risks

Prior 'careful screening' favored for invasive procedure's use in children

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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Noninvasive clinical assessments to identify children with pulmonary arterial hypertension (PAH) at risk of poorer outcomes align well with right heart catheterization (RHC), an invasive procedure, but they are not accurate enough to forgo a need for RHC altogether, according to a recent study.

Scientists found that about 70% of children considered clinically improved after starting PAH treatment would still be considered at a “high risk” of decline based on at least one unfavorable RHC measure.

“RHC still holds a central place in the care of patients with PAH,” but given the procedure’s potential risks, “children should be carefully screened” to determine when its repeat use might be necessary, the scientists noted.

The study, “Monitoring of Hemodynamics With Right Heart Catheterization in Children With Pulmonary Arterial Hypertension,” was published in the Journal of the American Heart Association.

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Monitoring, as well as diagnosing PAH, relies on RHC tests

PAH is a rare disease in which the pulmonary arteries carrying blood from the heart to the lungs become narrowed, causing the heart to work harder to pump blood.

Disease diagnosing and monitoring relies on RHC. In the procedure, a thin hollow tube is inserted into a vein in the neck, arm, or groin, enabling doctors to assess a patient’s hemodynamics, or measures of blood flow and heart function.

While central to PAH care, the procedure is invasive and associated with a risk of complications, particularly in pediatric patients.

Understanding is currently limited as to which hemodynamic measures obtained by catheterization are most useful in monitoring the disease in children, or how they relate with clinical measures. This means that it isn’t exactly clear how often the procedure is actually necessary in young patients.

Scientists in France looked into the relationship between RHC and clinical assessments for 71 children — 53 girls and 18 boys — diagnosed with PAH via right heart catheterization at a Paris clinic between January 2000 and October 2021. Their median age at diagnosis was 6.2 years.

After being diagnosed, seven children continued to go without treatment, while the others were given oral therapies: 32 a single treatment, 20 dual medications, and 12 a triple-combination treatment.

A number of hemodynamic measures at the first RHC were predictive of poorer clinical outcomes with time, defined as a need for a lung transplant, Potts shunt placement, or death. A Potts shunt is used to divert blood flow from the pulmonary arteries to reduce blood pressure in treatment-resistant patients.

Predictive measures included right atrial pressure or RAP, the filling pressure of the right heart; pulmonary vascular resistance or PVR, a measure of how hard it is for the heart to pump blood; pulmonary arterial compliance index or PACi, which evaluates pulmonary artery elasticity; and stroke volume index, an indicator of heart performance.

PVR, PACi, and RAP continued to associate with adverse outcomes at a follow-up assessment conducted a median of 7.4 months later.  These three measures “could not only be considered as prognosis factors but also as potential therapeutic targets since their changes with treatment were associated with changes in outcomes,” the researchers wrote.

Noninvasive clinical assessments included the New York Heart Association Functional Class, a classification of heart failure status based on functional capacity, as well as measures taken an echocardiogram, a test that using sound waves to image the heart.

When available, blood levels of NT-proBNP, a biomarker of heart failure, also were considered.

At a follow-up or second RHC, 57 children were considered to show clinical improvement and the other 14 to have no change or a worsening in their disease.

Generally, patients showing clinical improvement also have better hemodynamic measures, while those who worsen have no hemodynamic gains.

Abnormal hemodynamic measure seen in most children thought improving

Still, 40 of the 57 children (70%) considered improved had at least one abnormal hemodynamic measure on their follow-up RHC that would be considered a “high risk” for poorer outcomes. All those considered as clinically worsened also had at least one high-risk hemodynamic factor.

These findings highlight the importance of a follow-up RHC even in young patients who seem to improve with treatment, according to the researchers.

“Those patients may benefit from a therapeutic escalation, which would not have been detected if the evaluation was solely based on noninvasive parameters,” they wrote.

Researchers suggested that treatment adjustments for patients with worsening PAH be made before a follow-up test, since hemodynamic improvements are not likely without a change in treatment.

“Our results are in accordance with the most recent recommendations in the adult population,” the scientists added, noting that further studies are needed to confirm their findings.

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