PCSK9 and vascular disorder: The histological analysis revealed that the Pcsk9-/- group had significantly less allograft vasculopathy (Figure 2B, I/M ratio: 4.34 ± 0.52 vs. 1.51 ± 0.50; p < 0.05) and a significantly smaller neointimal area (Figure 2C, 15.88 ± 2.09 × 104 μm2 vs. 8.29 ± 1.35 × 104 μm2; p < 0.05) compared with the WT group.