Significance of a plasma D-dimer test in patients with primary pulmonary hypertension

Background: D-dimer, a degradation product of fibrin, has been increasingly used as a marker or prognostic factor in various thrombotic diseases. Objective: To assess the significance of a d-dimer test in patients with primary pulmonary hypertension (PPH). Patients and methods: Fourteen patients with PPH (12 women and 2 men) agd 25 to 68 years (mean ± SD age, 50 ± 14 years) entered the study. Plasma d-dimer was determined by Miniquant assay (Biopool International; Venture, CA) 3 ± 5 months after the disease onset, and patients were followed up for 1 year. We compared the d-dimer levels to the demographic, clinical, and hemodynamic data of the patients. Results: D-dimer levels were positively correlated with New York Heart Association classification (r = 0.59, p = 0.01) and pulmonary artery pressure (r = 0.43, p = 0.03) and were negatively correlated with oxygen saturation (r =-0.45, p = 0.03) and 6-min walk distance (r =-0.49, p = 0.04). One-year survival was also negatively correlated with d-dimer (point-biserial r =-0.71, p = 0.004), with a higher d-dimer value associated with poorer survival. No significant correlations were found between d-dimer values and sex, age, diffusing capacity of the lung for carbon monoxide, or cardiac index. Conclusion: D-dimer levels may have a role in the evaluation of patients with PPH. This simple, noninvasive test may be helpful for identifying patients who are at a higher risk for severe disease.