Endothelial biopsy was performed in patients with HF, LVAD, or OHT (n=10, 13, and 12 respectively) and endothelial cells were isolated by centrifugation. Cells were plated onto microscope slides and stained with fluorescent-labeled antibodies. Protein content was measured by quantitative immunofluorescence. Endothelial expression of Angiopoietin-2 (red) was significantly higher in patients with LVADs compared with HF or OHT. * p<0.05, † p<0.01