Patients with cardiovascular disorders also exhibit changes in the Ang/Tie system. Circulating Ang-1 concentrations are stable in patients with atrial fibrillation, but Ang-2 concentrations are increased, along with markers of platelet activation, angiogenesis and inflammation [30] . Patients with hypertension resulting in end-organ damage have increased levels of circulating Ang-1, Ang-2, Tie2 and VEGF [31] . Congestive heart failure is associated with elevated plasma levels of Ang-2, Tie2 and VEGF, but normal levels of Ang-1 [32]. A similar pattern is seen in acute coronary syndrome [33] .