Measuring Protein Levels May Improve Pulmonary Arterial Hypertension Diagnosis

Increased levels of the protein hematoma derived growth factor (HDGF) was linked to more severe pulmonary arterial hypertension in a recent study.

It is estimated that pulmonary arterial hypertension affects 200,000 Americans, the cause is not always clear. However, it can be linked to genetics or associated with HIV and other infections.

Currently there is no cure for the disease. In a study published in the American Journal of Respiratory and Critical Care Medicine, researchers developed a new test with the ability to measure levels of HDGF in the blood.

Blood samples from 39 patients with severe pulmonary arterial hypertension who failed treatment and were waiting for a lung transplant were examined, and compared with a control group of patient-matched healthy volunteers. The results revealed that median protein levels were approximately 7 times higher than the controls: 1.93 nanograms per milliliter in patients and 0.29 nanograms per milliliter in the controls.

Researchers then followed up with blood tests of HDGF levels in an additional 73 patients over 5 years. The results showed that patients with an HDGF level higher than 0.7 nanograms per milliliter walked shorter distances in a 6-minute walking test and had more extensive heart failure.

In survivors, the HDGF levels were lower (0.2 nanograms per milliliter) than in nonsurvivors (1.4 nanograms per milliliter), and had elevated HGDF levels associated with a 4.5-fold increased risk of death even after adjusting for disease type, heart function, age, and protein levels.

The authors noted that HDGF levels have an advantage over current clinical measures in predicting survival in patients with this disease.

The questions of why there is a link between pulmonary arterial hypertension and HDGF is still unanswered, but researchers believe that levels of HDGF may spike, which starts blood vessel healing when the lung arteries are stretched because of the disease.

Although using levels of HDGF for diagnosing pulmonary arterial hypertension shows primise, more work needs to be done.

“This has the potential to be a much more specific readout for the health of the lungs than what we currently measure using invasive cardiac catheterization,” said senior study author Allen Everett, MD. “It could really have value in making decisions about when to escalate therapy and when to ease it because at present, it's difficult to determine whether someone's disease is getting better or worse, especially in children.”