Cardiopulmonary Exercise Testing May Help Detect PAH in Scleroderma Patients, Study Suggests

Cardiopulmonary exercise testing (CPET), along with an algorithm that considers both lung and heart functions, can help lower the unnecessary use of right heart catheterization to determine if a scleroderma patient has pulmonary arterial hypertension, a study reports.

The study, “Cardiopulmonary exercise testing in a combined screening approach to individuate pulmonary arterial hypertension in systemic sclerosis,” appeared in the journal Rheumatology.

Pulmonary arterial hypertension (PAH) — a frequent and severe complication of scleroderma (SSc) — is characterized by thickening of connective tissue which narrows small arteries in the lung. This narrowing, in turn, increases pressure within pulmonary blood vessels.

Early detection and treatment of SSc-PAH has been associated with better prognosis but specific markers and symptoms have not been extensively investigated.

An algorithm called DETECT (a set of criteria related to heart and lung function) has led to a lower rate of missed diagnoses than other approaches. However, its low ability to identify SSc patients with little risk of PAH has led to frequent use of an invasive procedure called right heart catheterization.

CPET has been useful in the diagnosis of cardiopulmonary diseases, such as PAH, with recent evidence suggesting similar utility in scleroderma.

In the study, researchers in Italy investigated whether CPET could improve the performance of the DETECT-based screening strategy.

Over a 30-month period, the researchers screened 314 scleroderma patients. Of these, 54 individuals (two men and 52 women; mean age of 63.4 years) were deemed at risk for PAH according to the DETECT algorithm. As a result, they were referred to CPET before undergoing right heart catheterization.

CPET was conducted using a stationary cycle ergometer where patients worked up to the maximum exercise capacity that they can maintain for eight to 12 minutes, followed by three minutes of recovery.

Seventeen patients (31.5%) were diagnosed with PAH, according to the European Society of Cardiology/European Respiratory Society guidelines. Also, 23 patients (42.6%) had pre-capillary pulmonary hypertension, which is caused by blood pressure elevation in the pulmonary arterial system alone.

Importantly, an increased ratio of minute ventilation to carbon dioxide production — the VE/VCO₂ slope — in CPET was the best predictor of both pre-capillary and PAH diagnosis at right heart catheterization.

“In association with the DETECT algorithm, CPET may be considered as a useful tool in the workup of SSc-related pulmonary hypertension,” the researchers wrote.

“The sequential determination of the VE/VCO₂ slope in DETECT-positive subjects may reduce the number of unnecessary invasive procedures without any loss in the capability to capture PAH,” they added.