- After CABG, the serum NT-proBNP level increased gradually from N1 (972, 5 ± 1608, 05 pg / ml), increased andpeaked on N3 (4057, 26 ± 4458, 12 pg / ml), and then tended to decrease gradually at N5 (3457, 81 ±4110, 98 pg / ml), (p<0, 05).