Follow-up study on the utility of von Willebrand factor levels in the diagnosis of cardiac allograft vasculopathy

Abstract

Background: Cardiac allograft vasculopathy (CAV) is the major cause of late death in patients undergoing heart transplantation (HT). The most validated method for its diagnosis is intravascular ultrasound (IVUS), and there are no sufficiently reliable non-invasive methods. von Willebrand factor (vWF) is a marker of endothelial dysfunction/activity that is rarely studied in the context of CAV. The purpose of this study was to determine whether patients with higher levels of vWF in the first year post-transplant will develop a greater degree of CAV.

Methods: A prospective study of 113 consecutive cardiac transplant recipients was initiated in January 2002. vWF determinations were performed at 1, 2, 4, 6, 9 and 12 months post-transplant, at the same time as biopsies. Coronary arteriography and IVUS were performed on the first and last follow-up visits. Heart-lung transplants, retransplants and pediatric transplants were excluded from the study. Patients who died in the first month and those who refused consent were also excluded. The final analysis included 72 patients and 405 vWF determinations. CAV was defined as an intimal thickening of >or=0.5 mm on follow-up versus baseline IVUS. Patients with CAV (n = 41) and without CAV (n = 31) after 1 year of follow-up were compared.

Results: Patients who developed CAV had a higher prevalence of prior dyslipidemia, ischemic heart disease as the cause of HT, and rate of rejection, as well as higher vWF levels (321 +/- 122 vs 243 +/- 100%, p < 0.05). The receiver-operator characteristic (ROC) curve showed that vWF values of 150% provided a sensitivity of 91%, and values of 400% a specificity of 91% (p < 0.0001). The variables associated with CAV in the multivariate analysis were prior dyslipidemia, rejections and vWF, both linearly and by groups. vWF levels of 300% to 400% increased the probability of developing CAV by 390%, and levels >400% by 500%, versus levels <200%.

Conclusions: vWF levels determined in the first year post-transplant help to distinguish a subgroup of patients with a higher incidence of CAV.