Correlation of plasma adrenomedullin to myocardial preservation during open-heart surgery

Adrenomedullin (ADM) is a vasoactive peptide with potent dilatory effects. We studied whether perioperative myocardial injury could be altered by the presence of ADM. Blood samples from 19 children with congenital heart disea se undergoing surgical repair were collected at six time points: preoperati ve, on cardiopulmonary bypass (CPB), and 0, 3, 6, and 12 hours after CPB. B lood levels of ADM (pg/ml) and troponin-I (Tn-I; ng/ml), a specific marker of myocardial injury, were measured. Patients were divided into three group s based on their 12-hour Tn-I levels (I, < 10, n = 6, II, 10-25, n = 6; III , >25, n = 7). Preoperative Tn-I levels were within the normal range for al l patients. Preoperative ADM levels in group I (with little or no evidence of myocardial injury) were significantly greater than those of either group Ii or III (242.7 +/- 15.4 vs 83.8 +/- 18 and 85.2 +/- 5.5, respectively; p less than or equal to 0.0001 for each). The 12-hour ADM levels in group I remained significantly lower than preoperative levels (242.7 +/- 15.4 vs 19 7.4 +/- 11.6, p less than or equal to 0.03) but higher than in the other gr oups. In group III, ADM increased at the 12-hour time point (159.2 +/- 6.5, p less than or equal to 0.0001 vs baseline). Higher preoperative ADM level s are associated with lower levels of myocardial injury las assessed by tro ponin-I release) during congenital heart surgery.