High Pulmonary Pressure Predicts Development of PH in Systemic Sclerosis Patients, Study Suggests

People with systemic sclerosis (SSc) that have borderline high pulmonary arterial pressure are at increased risk of developing pulmonary hypertension (PH), and may benefit from regular examinations through right heart catheterization, a study found.

Pulmonary hypertension often appears as a disease complication of systemic sclerosis, reported to occur in 15 to 27 percent of patients who display symptoms of PH and in 8 to 12 percent of patients who don’t.

Given that PH development decreases the survival rate of SSc patients and that it is mostly diagnosed when the disease is already at an advanced stage, it is essential to provide an early diagnosis of PH in SSc patients.

In the study, “Incidence of pulmonary hypertension and determining factors in patients with systemic sclerosis,” published in the European Respiratory Journal, researchers set out to determine the rate of PH development and which factors can predict the disease among SSc patients who already have some respiratory impairment.

The study included 71 patients with SSc who had reduced lung gas transfer capacity (diffusing capacity for carbon monoxide, or DLCO, lower than 60%) and did not have PH, recruited from the DETECT study (NCT00706082).

Patients were assessed at the start and after a median follow-up period of three years for lung and heart function, the latter examined by right heart catheterization and echocardiography.

Mean pulmonary arterial pressure (mPAP) measured by right heart catheterization showed that 18 patients (25.3%) developed PH, and five (7%) developed SSc-associated pulmonary arterial hypertension by the end of the follow-up period.

Among patients with PH, five developed the condition due to left heart disease and eight due to lung disease.

Researchers found that SSc patients with borderline high mean pulmonary artery pressure (mPAP) at initial screening — between 21 and 24 mmHg — were at a higher risk of developing PH than those with normal values — less than 21 mmHg — over the three-year follow-up.

Accordingly, patients with high initial mPAP also showed significantly lower lung and heart function, both at the start of the study and at the end of the follow-up period.

Survival, however, was not worse in patients with initial mPAP of 21 to 24 mmHg, compared with those with normal values. In contrast, the presence of significant lung disease at baseline did significantly reduce survival after 40 months.

In addition to mPAP, researchers found that initial levels of pulmonary vascular resistance, the heart’s tricuspid regurgitation velocity, lung diffusion capacity, and the size of inferior vena cava measured by echocardiography were other predictors of PH development.

“In a selected cohort of SSc patients with a DLCO < 60%, pulmonary pressures appear to rise progressively during follow up. In this population using prospective RHC [right heart catheterization] during follow-up it was possible to identify manifest PH. … Therefore, regular clinical assessment including RHC might be useful in SSc-patients,” the researchers wrote.

“We also provide further evidence that borderline pulmonary arterial pressure is a possible intermediate stage in the development of pulmonary hypertension,” they said.