Patients with pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-APAH) have a higher mortality rate than non-SSc-APAH patients with idiopathic disease as well as those with other connective tissue diseases (CTD-APAH). In a recent study, researchers pinpoint specific predictors that put patients with SSc-APAH at higher risk of death.
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Researcher Lorinda Chung, MD, MS, a rheumatologist and allergist at Stanford University in Stanford, Calif., and colleagues, used the Registry to Evaluate Early and Long-Term PAH Management (REVEAL) patient population to identify mortality predictors among patients with SSc-APAH and non-SSc-CTD-APAH patients with previously or newly diagnosed PAH. The results of their analysis were published online in the July 3, 2014, issue of Chest.
Chung et al call their paper the first to identify low baseline systolic blood pressure (SBP) ≤ 110 mmHg as an independent predictor of death in patients with SSc-APAH. Additional risk factors for these patients include being a male older than 60 years; having poor exercise capacity, measured at a slow, six-minute walking distance (6MWD) <165 meters; and severe hemodynamic indices, including elevated mean right atrial pressure (mRAP) of >20 mmHg and elevated pulmonary vascular resistance >32 Wood units. The investigators note that predictors of mortality for patients with SSc-APAH were similar to core predictors for PAH as a whole.
“Our study provides further evidence that patients with SSc-APAH experience higher mortality rates than patients with other CTD-APAH in both incident and prevalent populations,” the authors write. “Our results validate the utility of the risk score calculator in patients with CTD-APAH, including patients with SSc-APAH.”
The investigators found that patients who were newly diagnosed with SSc-APAH had a 51% three-year survival, which was lower than the 61% survival seen in the previously diagnosed SSc-APAH group and much lower than the >75% survival in the non-SSc-CTD-APAH group.
“In our study, BNP [brain natriuretic peptide] >180 pg/mL increased the risk of death in both SSc[-APAH] and non-SSc-APAH patients by more than two-fold, as has been shown for patients with idiopathic PAH,” the authors write. “We and others have shown that patients with SSc-APAH have markedly elevated BNP and N-terminal-pro-BNP (NT-pro-BNP) levels compared with idiopathic PAH and non-SSc-CTD-APAH patients.”
Chung et al found that BNP <50pg/mL was protective in the SSc group, but not in the non-SSc group. By contrast, a 6MWD ≥440 meters was protective in the non-SSc-CTD-APAH group, but not in the SSc-APAH group.
The study used data from REVEAL, including an SSc-APAH cohort of 500 patients, a non-SSc-CTD-APAH cohort of 304 patients and an overall cohort of 3,515 patients. The SSc-APAH and non-SSc-CTD-APAH groups included only those patients who did not have interstitial lung disease. The investigators suggest that the identified risk factors may help clinicians identify patients with SSc-APAH who may benefit from closer monitoring and more aggressive treatment. (posted 8/8/14)