Research Activities, June 2013
More research needed for pulmonary arterial hypertension screening, management, and treatment
Comparative Effectiveness Research
More research is needed to determine the comparative validity, reliability, and feasibility of various screening, diagnostic, management, and treatment strategies for pulmonary arterial hypertension (PAH), concludes a new research review from AHRQ. This disease is rare and progressive and, if left untreated, can lead to heart failure and premature death. Specifically, the review finds that additional research is needed to determine if the combination of echocardiography and the biomarker N-terminal pro-B-type natriuretic peptide—two investigational diagnostic strategies for PAH—is sufficiently accurate to rule out the disease when testing patients with symptoms of PAH. Similarly, more research is needed to determine their effectiveness for screening asymptomatic patients who are at risk for PAH.
In patients with PAH, the biomarkers B-type natriuretic peptide and uric acid, as well as the size of the right atrium of the heart and the presence of pericardial effusion (fluid around the heart) correlate with disease prognosis. However, other parameters and biomarkers either show no correlation or have insufficient data. Although the studies were not designed to detect a mortality reduction from treatment, all drug classes and combination therapy regimens improve the distance covered during the 6-minute walk test and reduce hospitalization rates when compared with placebo. However, because of the diversity of treatment regimens and the small number of combination therapy trials, comparisons between specific treatment regimens are inconclusive. PAH, a subcategory of pulmonary hypertension, has an estimated prevalence of between 15 and 50 cases per million adults.
While the pathophysiology is not well understood, both genetic and environmental factors have been found to contribute to changes in the pulmonary vasculature, causing increased pulmonary vascular resistance. This increased resistance, if unrelieved, progresses to right ventricular pressure overload, dysfunction, and ultimately right heart failure and premature death. The causes of PAH are numerous, and before the availability of disease-specific therapy in the mid-1980s, the median life expectancy at the time of diagnosis was 2.8 years.
These findings are available in the research review, Pulmonary Arterial Hypertension: Screening, Management, and Treatment at http://go.usa.gov/Tz75.