Background: The clinical characteristics, hemodynamic changes and outcomes of lung disease-associated pulmonary hypertension (LD-PH) are poorly defined. Methods: A prospective cohort of PH patients undergoing initial hemodynamic assessment was collected, from which 51 patients with LD-PH were identified. Baseline characteristics and long-term survival were compared with 83 patients with idiopathic pulmonary arterial hypertension (iPAH). Results: Mean age ( ± standard deviation) of LD-PH patients was 64 ± 10 years, 30% were female and 78% were New York Heart Association class III-IV. The LD-PH group was older than the iPAH group (64 ± 10 vs 56 ± 18 years, respectively, P = 0.003) with a lower percentage of women (30% vs 70%, P = 0.007). LD-PH patients had smaller right ventricular sizes (P = 0.02) and less tricuspid regurgitation (P = 0.03) by echocardiogram, and lower mean pulmonary arterial pressures (mPAP) (P = 0.01) and pulmonary vascular resistance (PVR) (P = 0.001) at catheterization. Despite these findings, mortality was equally high in both groups (P = 0.16). 5-year survival was lower in patients with interstitial lung disease compared to those with obstructive pulmonary disease (P = 0.05). Among the LD-PH population, those with mild to moderately elevated mPAP and those with PVR < 7 Wood units demonstrated significantly improved survival (P = 0.04 and P = 0.001, respectively). Vasoreactivity was not associated with improved survival (P = 0.64). A PVR ≥7 Wood units was associated with increased risk of mortality (hazard ratio (95% confidence interval), 3.59 (1.27-10.19), P = 0.02). Conclusions: Despite less severe PH and less right heart sequelae, LD-PH has an equally poor clinical outcome when compared to iPAH. A PVR ≥7 Wood units in LD-PH patients was associated with 3-fold higher mortality.
The investigation of pediatric pulmonary hypertension (PH) drugs has been identified as a high priority by the United States National Institutes of Health (NIH). Studying pediatric PH is challenging due to the rare and heterogeneous nature of the disease. We sought to define the pediatric PH clinical trials landscape, to evaluate areas of trial success or failure, and to identify potential obstacles to the study of pediatric PH drugs. Interventional pediatric (ages 0–17 years) PH trials registered on ClinicalTrials.gov from June 2005 through December 2014 were analyzed. There were 45 pediatric PH trials registered during the study period. Median (IQR) projected trial enrollment was 40 (24–63), with seven trials (16%) targeting > 100 participants. Industry was the most common trial sponsor (n = 23, 50%), with only two (4.4%) NIH-sponsored trials. Phosphodiesterase inhibitors were the most frequently studied drug (n = 18, 39%). Single group study designs were used in 44% (n = 20) with an active comparator (parallel, factorial, or cross-over designs) in 25 trials, including 22 with randomization and ten that were double-blinded. Study outcomes varied markedly with inconsistent use of known surrogate and composite endpoints. One-third of trials (n = 15, 33%) were terminated, predominantly due to poor participant enrollment. Of the 17 completed trials, 11 had published results and only three efficacy trials met their primary endpoint. There are unique challenges to drug development in pediatric PH, including enrolling patients, identifying appropriate study endpoints, and conducting randomized, controlled, double-blind trials where the likelihood of meeting the study endpoint is optimized.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.