Chest
Volume 135, Issue 1, January 2009, Pages 130-136
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Original Research
Pulmonary Arterial Hypertension
Hemodynamics and Epoprostenol Use Are Associated With Thrombocytopenia in Pulmonary Arterial Hypertension

https://doi.org/10.1378/chest.08-1323Get rights and content

Background

Thrombocytopenia develops in some patients with advanced pulmonary arterial hypertension (PAH) while receiving IV epoprostenol therapy. In this study, we evaluate whether epoprostenol use, other PAH medication use, hemodynamics, or PAH etiology are associated with thrombocytopenia in PAH.

Methods

Platelet counts were evaluated in 47 PAH patients receiving IV epoprostenol, and in 44 patients with an inadequate response to initial therapy with oral agents in a cross-sectional study. Associations between thrombocytopenia (platelet count < 150,000/mL) and epoprostenol use, hemodynamics, PAH etiology, and use of other PAH medications were evaluated in univariable and multivariable analyses.

Results

PAH subtypes included idiopathic (69%), fenfluramine (18%), connective tissue disease (10%), and congenital heart disease (2%)-associated PAH. Thrombocytopenia was observed in 34% of patients treated with epoprostenol, compared with 15% of patients receiving oral therapy (odds ratio [OR], 2.9; p < 0.05), and the association between epoprostenol and thrombocytopenia remained significant after adjustment for differences in hemodynamics (OR, 5.0; p < 0.05). Right atrial pressure (OR, 1.12 per mm Hg; p < 0.05) and mixed venous oxygen saturation (Svo2) [OR, 0.92 per percentage; p < 0.05] were also associated with thrombocytopenia in univariable analyses; after logistic regression analysis, both the use of epoprostenol and Svo2 were independently associated with thrombocytopenia. In a separate analysis including only patients with current or prior epoprostenol use, epoprostenol dose and right atrial pressure were inversely associated with platelet count.

Conclusion

Epoprostenol use and severity of hemodynamic abnormalities are associated with thrombocytopenia in PAH, and these effects appear to be independent and additive.

Section snippets

Materials and Methods

This study included current and former epoprostenol-treated PAH patients seen over a 12-month period as well as a comparison group of PAH patients receiving oral therapy. Patients were required to have undergone right-heart catheterization while receiving treatment and have a platelet count within 1 month of catheterization. In order to minimize potential bias related to the severity of PAH, oral therapy patients were included only if they had had an “inadequate response” to their current

Results

A total of 93 patients with PAH were studied, including 47 patients currently receiving epoprostenol, 6 patients who had previously received epoprostenol, and 40 patients receiving oral therapy with plans to add on an oral, inhaled, or IV agent. Patients had idiopathic PAH (69%), and PAH associated with fenfluramine use (18%), connective tissue disease (10%), or congenital heart disease (2%). Frequency of PAH subgroups was similar among patients receiving epoprostenol compared with those

Discussion

The results of this study suggest that abnormal right-heart hemodynamics and use of epoprostenol are associated with thrombocytopenia in patients with severe PAH, and that higher doses of epoprostenol are associated with lower platelet counts than lower doses of epoprostenol. The effects of hemodynamic abnormalities and epoprostenol were independent and additive, with the highest rates of thrombocytopenia seen among patients with both severe hemodynamic abnormalities and use of epoprostenol.

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  • Cited by (0)

    This work was performed at University of Texas Southwestern and University of California, San Diego.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

    1

    Drs. Chin, Channick, Kim, Rubin, and Torres have received consulting fees and/or honoraria from Gilead, distributor of Flolan (epoprostenol).

    2

    Dr. de Lemos had no disclosures.

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