Study Evaluates Pediatric PAH Risk Assessment Tool and PPAH Survival in China

The simplified, noninvasive risk stratification tool for pediatric pulmonary arterial hypertension (PPAH) proposed by the World Symposium on Pulmonary Hypertension (WSPH) demonstrated good performance for predicting survival in Chinese children with PAH, according to clinical trial findings published in Chest.

The WSPH pediatric risk stratification tool has yet to be fully tested and accepted, according to study investigators. Additionally, there is limited data on the characteristics and survival of patients with PPAH in developing countries, said study authors. They therefore sought to evaluate the value of the PPAH risk assessment tool as well as to describe the characteristics and long-term survival of children with PPAH in China.

 To accomplish this, the investigators conducted a prospective, multicenter study (ClinicalTrials.gov identifier: NCT01417338) analyzing data collected between August 20009 and December 2019 on pediatric patients (aged 3 to 18 years) from a Chinese PAH registry. All participants had been clinically diagnosed with PAH according to contemporary guidelines (ie, mean pulmonary arterial pressure [mPAP] of ≥25 mm Hg, pulmonary capillary wedge pressure of ≤15 mm Hg at right heart catheterization [RHC], and/or supportive evidence of the absence of left heart disease, including the normal structure of the heart, as well as normal systolic and diastolic function).

The analysis included 247 children with newly diagnosed PPAH (ie, incident cases, with diagnostic RHC within 6 months prior to enrollment) as well as those with previously diagnosed (ie, prevalent cases) PPAH. Overall, 58.3% of the participants were female. The median patient age was 14.8 years.

PAH associated with congenital heart disease (APAH-CHD) was reported in 61.5% of the participants; PAH linked to idiopathic/heritable PAH (IPAH/HPAH) was reported in 37.7% of the participants. The median time from symptom onset to diagnosis of PAH was 24 months. The mean (SD) PAP and pulmonary vascular resistance index were 70.78 (19.80) mm Hg and 21.82 (11.18) Wood units/m², respectively.

Participants with APAH-CHD experienced a lengthier diagnostic delay and a higher PAP, but better cardiac performance, than did those with IPAH/HPAH. An increased number of individuals received targeted therapy at the last follow-up compared with baseline. In the entire cohort, the 5-year and 10-year survival rates were 74.9% and 55.7%, respectively, with better survival in participants with APAH-CHD than in those with IPAH/HPAH.

Risk was evaluated both at baseline and at follow-up based on the simplified noninvasive risk score model with weight, function class, and echocardiographic right ventricular size. Patients at “low risk” had better survival compared with those with “high risk.”

Several limitations of the current study warrant mention. Because the participants were enrolled from 19 tertiary centers in China and RHC was essential for study inclusion, some patients diagnosed by echocardiography or referred to primary and secondary hospitals may have been excluded, resulting in possible selection bias. Further, because of the observational design of the study, some variables for risk stratification were missing, particularly in follow-up.

The authors concluded that “The long-term survival of PPAH is poor, despite the increased utility of targeted drugs. The simplified noninvasive risk model demonstrated good performance for predicting survival in Chinese children with PAH.”

The study authors concluded that “The simplified noninvasive risk model demonstrated good performance for predicting survival in Chinese children with PAH.” They further noted that in China, patients with PPAH “had severely compromised hemodynamics with marked diagnostic delay,” with a 10-year survival rate of 55.7%.