Prevalence and outcome in systemic sclerosis associated pulmonary arterial hypertension: application of a registry approach

Abstract

Objective: To determine the prevalence of systemic sclerosis associated pulmonary arterial hypertension (SScPAH), evaluate outcome, and identify predictors of mortality in a large patient cohort.

Methods: A prospective four year follow up study of 794 patients (722 from our own unit and 72 referrals). All patients screened for PAH using a combination of echocardiography, lung function testing, and clinical assessment. Patients with suspected raised pulmonary artery systolic pressures of >35 mm Hg, carbon monoxide transfer factor (TLCO) <50% predicted, or a precipitous fall in TLCO >20% over a one year period with no pulmonary fibrosis, and patients with SSc with breathlessness with no pulmonary fibrosis found were investigated with right heart catheterisation. All patients with SScPAH were treated in accordance with current best practice.

Results: The prevalence of PAH was 12% (89/722) by right heart catheter. The survival was 81%, 63%, and 56% at 1, 2, and 3 years from the diagnosis (in 89 patients from our own cohort and 59/72 referrals). Haemodynamic indices of right ventricular failure--raised mRAP (hazard ratio 21), raised mPAP (hazard ratio 20), and low CI (hazard ratio 11) predicted an adverse outcome There was no significant difference in survival between patients with SScPAH with (n=40) and without (n=108) pulmonary fibrosis (p=0.3).

Conclusions: The prevalence of SScPAH in this cohort was similar to that of other catheter based studies and lower than that of previous echo based studies. The 148 patients with SScPAH actively treated had comparable outcomes to those of the cohorts with primary pulmonary hypertension. A high mRAP was the strongest haemodynamic predictor of mortality. To improve prognosis, future treatments need to be implemented at an earlier disease stage to prevent right ventricular decompensation.

Figure 1

Cumulative survivals of 148 patients with SScPAH between March 1998 and September 2002.

Figure 2

Kaplan-Meier survival curves for 148 patients with SScPAH divided into tertiles—47 with mPAP <32 mm Hg, 48 with mPAP = 32–44 mm Hg, and 53 with mPAP >45 mm Hg. There was a significant difference in mortality between the three groups (p<0.01 between each group).

Figure 3

Kaplan-Meier survival curves for 108 patients with isolated SScPAH and 40 patients with pulmonary fibrosis related SScPAH (p=0.3).

Figure 4

Survival according to degree of vasoreactivity to acute iloprost challenge in 129 patients with SScPAH divided into tertiles of PVR change (ΔPVR)—40 patients had a ΔPVR of <20%, 50 had a ΔPVR of 20–34%, and 49 had a ΔPVR of ⩾35%. There was no significant difference in survival between the three groups (p=0.8).