Circulating von Willebrand factor antigen as a predictor of short-term prognosis in pulmonary hypertension

Study objective: To determine the potential value of plasma von Willebrand factor antigenic activity (vWF:Ag) and other commonly measured clinical variables for predicting which patients with precapillary pulmonary hypertension would be unlikely to survive 1 year. Design: Prospective clinical study. The data obtained at the beginning of the study were analyzed at the end of the first year of follow-up. Patients and methods: Forty patients aged 1.2 to 45 years (median, 24 years) entered the study. Eleven patients had primary pulmonary hypertension, and in the remaining ones, pulmonary-vascular disease was associated with antiphospholipid syndrome (n = 1), collagen vascular disease (n = 1), schistosomiasis (n = 3), or congenital heart defects (Eisenmenger's syndrome) (n = 24), Plasma vWF:Ag was determined by electroimmunodiffusion, and the results were expressed as the percentage of activity. Results: Seven of 11 patients with primary pulmonary hypertension but only 4 of 29 patients with secondary pulmonary hypertension died during the follow-up period (p < 0.005). Initial vWF:Ag values were significantly higher in the nonsurvivor group in comparison with the survivors (256.6 +/- 85.3% and 132.0 +/- 59.3% activity; respectively; p < 0.0001), The likelihood of fatal outcome as a function of plasma vWF:Ag levels was estimated for primary and secondary pulmonary hypertensive patients using logistic regression analysis. Decreased life expectancy was significantly related to high vWF:Ag levels and an established diagnosis of primary pulmonary hypertension, A plasma vWF:Ag of >240% (p = 0.003) was 54% sensitive and 93% specific for identifying patients who were unlikely to survive 1 year, with an overall predictive value of 75%. No other variables correlated significantly with survival. Conclusion: Plasma vWF:Ag seems to be a useful biochemical index for predicting short-term prognosis in patients with pulmonary hypertension. In contrast to hemodynamic and histopathological predictors of survival, vWF:Ag does not require invasive techniques to be determined. In light of the possibility of false-negative results, serial measurements should be performed over time in patients with vWF:Ag of <240%, This observation proved helpful in two patients in this study.