Essentially, our study demonstrates that plasma vWF:Ag, a biochemical marker of endothelial cell dysfunction, may be a useful index for identifying patients with pulmonary hypertension who are unlikely to survive 1 year, suggesting a pathophysiological relationship between endothelial cell dysfunction and the severity of pulmonary vascular disease. In addition, exceedingly high vWF plasma levels in patients with primary pulmonary hypertension seemed to be particularly worrisome. The value of elevated vWF:Ag in identifying patients who are unlikely to survive also has been demonstrated in acute disorders such as sepsis syndrome. An important limitation of this study is that in many instances parameters previously identified as predictors of survival in pulmonary hypertension were not available for analysis. Consequently, we were unable to establish how much survival was influenced by variables such as cardiac index, right atrial pressure, and histopathological features of pulmonary arteries. this Our results should, therefore, be interpreted cautiously in light of the number of variables other than endothelium dysfunction that might have influenced patient outcome in such a complex disorder.
Another point of caution is the small number of patients with pulmonary hypertension secondary to disorders other than congenital heart disease. Although in a preliminary analysis, these patients seemed to behave exactly as did patients with congenital cardiac defects, in terms of outcome, further studies obviously are necessary for a better understanding of vWF changes and their prognostic implications in different forms of precapillary pulmonary hypertension.
Despite the limited number of variables that we analyzed, the highly significant correlation observed between elevated vWF:Ag levels and death during the first year of follow-up suggests that the altered metabolic function of endothelial cells is an important determinant of patient outcome in precapillary pulmonary hypertension. The etiology of the disease also was shown to influence survival, ie, patients with primary pulmonary hypertension had a higher mortality rate in interval.