NOS3 and endothelial dysfunction: Hypertension could cause endothelial dysfunction by reducing NO synthesis in endothelial cells [20]–[22], and the abilities of repairing damaged vascular and inhibiting platelet aggregation and smooth muscle cell proliferation might be suppressed severely in hypertensive subjects, therefore, the hypertensive subjects were inclined to suffer from DVT after orthopedic surgery, and the mutation of NOS3 might play a more important role of DVT after orthopedic surgery in hypertensive subjects compared with normotensive subjects.