Distribution of serum activin A levels in low-, intermediate-, and high-risk groups. ACS patients were divided into three subgroups according to TIMI risk score: group 1 [low TIMI risk score (1-2)], group 2 [intermediate TIMI risk score (3-4)], group 3 [high TIMI risk score (≥5)]. Activin A levels were 629.8±446.8 pg/mL in the low-risk group, 665.5±653.9 pg/mL in the intermediate-risk group, and 680.4±504.0 pg/mL in the high-risk group (P=0.590)