Circulating von Willebrand Factor Antigen as a Predictor of Short-term Prognosis in Pulmonary Hypertension: Discussion
In three of our patients, the results of two determinations of plasma vWF:Ag were available. In two patients (a 37-year-old woman with primary pulmonary hypertension and a 40-year-old woman with a persistent ductus arteriosus), heightened vWF:Ag in the second sample relative to the first one (80 and 49% increases, respectively) was followed by a fatal outcome a few months later. The third patient (an 8-year-old boy) was the only case of regression of primary pulmonary hypertension that we have ever seen among our pediatric patients. At the beginning of the study, this patient had a mean pulmonary arterial pressure at rest of 45 mm Hg. Plasma vWF:Ag was 226%. One year later, the mean pulmonary arterial pressure was 20 mm Hg and vWF :Ag was 130%.
This study involved pediatric and adult patients with precapillaiy pulmonary hypertension. Most of the patients had New York Heart Association class III or IV symptoms that were compatible with moderate to severe pulmonary vascular disease. Despite the fact that the patient population was mixed in terms of the etiology of pulmonary hypertension, the overall mortality ratio of 27% at 1 year was within the range (23 to 32%) reported for primary pulmonary hypertension. It has been suggested that children with primary pulmonary hypertension have a higher mortality within 1 year of follow-up than do patients older than 14 years. In this study, shortterm prognosis was not significantly influenced by patient age. In particular, young patients did not have a higher mortality ratio, probably because 7 of 11 patients younger than 14 years of age had secondary pulmonary hypertension, which was associated with a better prognosis. Pulmonary artery pressure has been demonstrated to impact on survival in patients with primary pulmonary hypertension. Such a correlation was not observed in our patients. A likely explanation for this apparent discrepancy is that the impact of hemodynamic parameters on survival, which has been reported for patients with primary pulmonary hypertension, may not be as evident in mixed patient populations that include patients with congenital heart defects as was the case in the present study.