Survival in schistosomiasis-associated pulmonary arterial hypertension

Objectives: The objective of this study was to evaluate the natural history of untreated schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients as compared to idiopathic pulmonary arterial hypertension (IPAH) with respect to hemodynamics recorded at presentation and 36 months survival.

Background: Schistosomiasis (Sch) is one of the most prevalent chronic infectious diseases in the world. Nevertheless data regarding one of its most severe clinical complications, pulmonary arterial hypertension (PAH), is scarce.

Methods: We retrospectively analyzed case notes of all consecutive patients diagnosed of Sch-PAH and IPAH referred to the Heart Institute in São Paulo, Brazil, between 2004 and 2008. None of the Sch-PAH received PAH specific treatment whereas all IPAH patients did.

Results: Sch-PH patients (n = 54) had less severe pulmonary hypertension as evidenced by lower levels of pulmonary vascular resistance (11.3 +/- 11.3 W vs. 16.7 +/- 10.6 W; p = 0.002) and mean pulmonary artery pressure (56.7 +/- 18.7 mm Hg vs. 64.6 +/- 17.4 mm Hg; p = 0.01) and higher cardiac output (4.62 +/- 1.5 l/min vs. 3.87 +/- 1.5 l/min; p = 0.009) at presentation than IPAH patients (n = 95). None of the Sch-PAH patients demonstrated a positive response to acute vasodilator testing, whereas 16.2% of IPAH patients did (p = 0.015). Survival rates at 1, 2, and 3 years were 95.1%, 95.1%, and 85.9% and 95%, 86%, and 82%, for Sch-PAH and IPAH, respectively (p = 0.49). Both groups had a higher survival rate when compared to IPAH survival as estimated by the NIH equation (71%, 61%, and 52%, respectively).

Conclusions: Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.