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Erythropoietin Levels in Patients with Pulmonary Arterial Hypertension [PAH]

Rebecca Miller

P. Patel

Nina Kohn

Arunabh Talwar

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Conference: 2011 PH Professional Network Symposium

Release Date: 09.22.2011

Presentation Type: Abstracts

R. Miller, BA, P. Patel, MD, P. Patel, MD, N. Kohn, MA, A. Talwar, MD 
North Shore - LIJ Health System, Manhasset, NY

OBJECTIVE: To determine if an elevated erythropoietin level is correlated with a decrease in functional abilities as measured by WHO functional class in patients with pulmonary arterial hypertension (PAH). We hypothesized that as patients' pulmonary hypertension progressed, they would suffer from increasing hypoxic events, leading to elevation of serum erythropoietin.

BACKGROUND/SIGNIFICANCE: Erythropoietin (EPO), a glycoprotein produced primarily by the kidney, is a factor in regulating red blood cell (RBC) production. Renal production of EPO is regulated by changes in oxygen availability. Under conditions of hypoxia, the level of EPO in circulation increases, leading to increased production of RBCs.

METHODS: 55 patients [13 males and 42 females with a mean age of 55.9 years] with confirmed WHO Group I pulmonary hypertension, a mean pulmonary artery pressure (mPAP) ≥25mmHg, and pulmonary capillary wedge pressure (PCWP) ≤18mmHg were studied. Only patients with Hg>12g/dL and serum creatinine <1.8 mg/dL were included in the study. The WHO functional class at time of obtaining erythropoietin analysis was obtained by physician determination based on the patient's self-reported symptoms. Serum erythropoietin levels were measured at time of patient's initial outpatient evaluation. Analysis was performed with SAS® software.

RESULTS: The mean serum erythropoietin level was 34.34 mIU/mL (±52.93), with a minimum value of 4.3 mIU/mL and a maximum value of 356.0 mIU/mL. Mean oxygen saturation was 91.98%±6.96. Mean creatinine was 0.9 mg/dL ±0.22. Mean hemoglobin was 14.19g/dL±1.82. The highest levels of serum erythropoietin were observed in patients with Eisenmengers complex, which is likely related to their underlying disease physiology. There was a significant difference between EPO levels between patients with functional classes I and II [Mean 34.4±63.0, Median 16.0, interquartile range 16.8; n=35] versus functional classes III and IV [Mean 33.3±29.8; Median 22.0, IQR 17.9 n=19]. {P<0.03; Mann-Whitney Test}

CONCLUSIONS: Our study confirms that serum erythropoietin levels are elevated in patients with PAH, and higher levels may correlate with worsening functional class. Further studies are needed to clearly and concisely determine the role erythropoietin and its correlation to the severity of PAH.

IMPLICATIONS: Elevation of erythropoietin is observed in PAH and may be a marker of disease severity.