Fluid restriction in patients with pulmonary arterial hypertension and right heart failure

Background: In pulmonary arterial hypertension (PAH) right heart (RH) failure is associated with high mortality and poor prognosis. The objective of this cohort study was to assess, whether reduction of fluid-intake is associated with RH size and clinical outcome in PAH patients. Methods: A retrospective, exploratory analysis of patients with invasively diagnosed PAH and signs of fluid retention who were routinely clinically monitored for 8.4±5.3 months including fluid-uptake and signs of RH failure was performed. Patients were advised to reduce fluid-uptake to a maximum of 2 litres per day (l/d) according to clinical routine. Clinical characteristics of patients with normal fluid-intake <2l/d vs. high fluid-intake ≥2l/d and patients who reduced vs. patients with increased fluid-intake during follow-up were compared. Furthermore, the influence of hospitalization due to fluid overload and for treatment with iv diuretics at baseline and fluid-intake on survival and time to clinical worsening (TTCW) were investigated. Results: Out of 66 patients with signs of fluid retention at baseline (normal fluid-intake <2l/day, n=16; high fluid-intake ≥2l/d, n=50), 21 presented with hospitalization due to fluid overload, which was significantly associated with worse survival (p=0.004) and TTCW (p<0.001). During follow-up patients who reduced fluid-intake <2l/day presented with in trend reduced right ventricular area (p=0.051) and longer TTCW (p=0.007). Hospitalisation due to fluid-overload and fluid-intake during follow-up were independent predictors of TTCW. Conclusions: Restriction of fluid-intake in PAH patients was highly effective and associated with significantly longer TTCW. Further evaluation of fluid restriction in PAH patients is needed in larger studies.