Standardized fluid-challenge testing to distinguish Pulmonary Arterial Hypertension (PAH) from pulmonary hypertension secondary to heart failure

Abstract

Purpose: Pulmonary arterial hypertension (PAH) and pulmonary hypertension secondary to (diastolic) heart failure requires different clinical management. Current guidelines recommend the use of pulmonary capillary wedge pressure (PCWP) to distinguish both conditions. However, within a patient PCWP is quite variable depending on volume-state. Therefore, a patient with a PCWP below 15 mmHg can be falsely classified as PAH. For these cases, the use of differential PCWP-response to fluid-challenge has been suggested. However, this has not been systematically investigated, and especially the minimally required fluid-loading has not been determined yet. Methods: Patients (n=17; 2 male/15 female, age 65±13 years, body mass index 30±7 kg/m2, plasma BNP-level 359±311 pg/ml) referred for analyses of pulmonary hypertension with borderline PCWP between 2010 and 2013 underwent right heart catheterization with standardized fluid-challenge testing (600 ml saline in 18 minutes). A PCWP below 15 mmHg after fluid-challenge was considered diagnostic for PAH, in accordance to current clinical guidelines. Results: No complications occurred in any patient tested. Fluid-loading resulted in an initial rise in PCWP and leveled after 400 ml (Fig. 1A). After fluid-challenge, 9 of 17 patients had a PCWP above 15 mmHg. These patients could already be identified using 400 ml of fluid-loading (Fig. 1B). (Figure presented) Conclusions: Fluid-challenge testing is feasible and safe in patients with pulmonary hypertension. Fluid-loading of 400 ml is sufficient to reveal a differential fluid response.