Screening is important to determine whether patients with
systemic sclerosis (SSc) have
pulmonary hypertension because earlier
pulmonary hypertension treatment can improve survival in these patients. Although decreased
transfer factor of the lung for
carbon monoxide (TLCO) is currently considered the best pulmonary function test for screening for
pulmonary hypertension in SSc, small series have suggested that partitioning TLCO into membrane conductance (diffusing capacity) for
carbon monoxide (DMCO) and alveolar capillary blood volume (VC) through combined measurement of TLCO and
transfer factor of the lung for
nitric oxide (TLNO) is more effective to identify
pulmonary hypertension in SSc patients compared with TLCO alone. Here, the objective was to determine whether combined TLCO-TLNO partitioned with recently refined equations could more accurately detect
pulmonary hypertension than TLCO alone in SSc.For that purpose, 572 unselected consecutive SSc patients were retrospectively recruited in seven French centres.Pulmonary
hypertension was diagnosed with right heart catheterisation in 58 patients. TLCO, TLNO and VC were all lower in SSc patients with
pulmonary hypertension than in SSc patients without
pulmonary hypertension. The area under the receiver operating characteristic curve for the presence of
pulmonary hypertension was equivalent for TLCO (0.82, 95% CI 0.79-0.85) and TLNO (0.80, 95% CI 0.76-0.83), but lower for VC (0.75, 95% CI 0.71-0.78) and DMCO (0.66, 95% CI 0.62-0.70).Compared with TLCO alone, combined TLCO-TLNO does not add capability to detect
pulmonary hypertension in unselected SSc patients.