ENPP2 and cardiac hypertrophy: As Figure 6 showed, the serum autotaxin level was negatively correlated with EF value (Figure 6A; r = −0.4263, P < 0.01), but positively associated with serum level of NT‐proBNP, an important marker of cardiac hypertrophy (Figure 6B; r = 0.4091, P < 0.01).