Researchers at the National Institutes of Health (NIH) have found that a blood test can be used to evaluate disease severity in patients with pulmonary arterial hypertension (PAH), a rare, life-threatening condition.
The new blood test measures DNA fragments shed by damaged cells; according to the NIH, the test could also be used to predict survivability.
The researchers found that these fragments of cell-free DNA (cfDNA) were elevated in the blood of patients with PAH and increased with disease severity.
If future studies confirm the findings, the blood test could allow doctors to intervene faster to prevent or delay progression of the disease and possibly save lives, NIH said.
The study was funded by the National Heart, Lung, and Blood Institute (NHLBI) and the NIH Clinical Center, and the findings were recently published online in Circulation.
The blood test could allow researchers to better pinpoint the specific tissues involved in the PAH disease process, knowledge that may lead to new drug interventions for PAH, whose current treatment options may slow but not halt or reverse disease progression, NIH said.
PAH is a rare form of pulmonary hypertension that can cause difficulty breathing, chest pain, and fatigue. Patients with PAH have a high death rate, and the condition mostly affects women. Despite treatment advances, it currently has no cure.
Current tests used to monitor PAH severity rely on established risk prediction scores based on clinical symptoms and on the use of an invasive catheter to measure pressure in the lungs, NIH noted.
Doctors sometimes use echocardiography, or heart imaging, to measure heart pressure as an indirect measurement of lung pressure, but these tests tend to lack reliability and sensitivity.
In the new study, the researchers showed that the cfDNA test could significantly improve upon conventional tests, NIH said.
"Researchers have been actively searching for novel, less-invasive approaches to evaluate PAH severity, disease progression, and response to therapy for more than a decade," Dr. Michael Solomon, a study coauthor, said in a statement. Solomon is part of the NHLBI Cardiovascular Branch and codirector of the NIH Clinical Center Pulmonary Arterial Hypertension Section.
The cfDNA analyses uncovered in the study represent progress toward the goal of effectively evaluating PAH severity, disease progression, and response to therapy, the researchers said.
In the current study, the research team analyzed cfDNA from blood samples taken from 209 adult patients, predominantly women, diagnosed with PAH at two large U.S. medical centers. The researchers compared the results to cfDNA measured from a control group of 48 healthy volunteers without PAH at the NIH Clinical Center.
They found that cfDNA was elevated in patients with PAH, and that cfDNA concentrations increased in proportion to the severity of the disease. Patients with the highest level of cfDNA had a 3.8 times greater risk of either death or need for lung transplantation compared to those with the lowest level of cfDNA, the researchers said.
Further analyses of cfDNA samples revealed that multiple tissue types -- including the heart, blood vessels, fat tissue, and inflammatory cells circulating in the blood -- were affected by PAH, the NIH said.
