Sodium nitroprusside during coronary artery bypass grafting: evidence for an antiinflammatory action

Background. It was the aim of the present study to investigate whether a nitric oxide donor can reduce systemic inflammation and the cardiac inflammatory response during coronary artery bypass grafting with cardiopulmonary bypass. Methods. Patients undergoing elective coronary artery bypass grafting (n = 22) were randomly assigned to treatment with either sodium nitroprusside (0.5 μg • kg−1 • min−1) or placebo (controls), both for the first 20 minutes of reperfusion. Interleukin-6 and interleukin-8 levels, the adhesion molecules CD41 and CD62 on platelets and CD41 on monocytes and PMN (as markers for coaggregate formation), CD11b on monocytes and PMN, as well as platelet and leukocyte counts were determined in radial artery and coronary sinus blood before cardiopulmonary bypass and during reperfusion (1, 5, 10, 25, and 35 minutes). Results. A reduction of systemic interleukin-6 levels (15.4 ± 3.5 pg/mL, 36.7 ± 5.9 pg/mL, and 46.8 ± 8.0 pg/mL versus 33.4 ± 7.7 pg/mL, 76.7 ± 13.2 pg/mL, and 106.0 ± 26.5 pg/mL, respectively, at 1, 25, and 35 minutes of reperfusion) and interleukin-8 (29.6 ± 4.5 pg/mL versus 54.0 ± 9.4, pg/mL, resp., at 35 minutes of reperfusion) resulted from treatment with sodium nitroprusside. No intracardiac production of interleukin-8 in sodium nitroprusside-treated patients (−1.1 ± 0.4 pg/mL and −2.8 ± 2.2 pg/mL, resp., for the coronary sinus–radial artery difference at 5 and 25 minutes of reperfusion) was observed, whereas cardiac production of interleukin-8 was present in controls (2.5 ± 1.5 pg/mL and 5.5 ± 2.8 pg/mL, resp.). Retention of platelet/leukocyte coaggregates occurred during coronary passage in controls (coronary sinus–radial artery difference for CD41-positive monocytes at 1 and 10 minutes of reperfusion, −16.3% ± 8.5% and −8.8% ± 2.6%, resp.). This was reduced in sodium nitroprusside-treated patients (with 5.8% ± 5.2% and 0.0% ± 3.2%). Retention of platelets in controls (ratio of coronary sinus to radial artery platelet count at 5 and 10 minutes of reperfusion, 88% ± 6% and 91% ± 5%) was compared to washout in treated patients (108% ± 6% and 113% ± 7%). Conclusions. In patients undergoing routine coronary artery bypass grafting, administration of sodium nitroprusside during early reperfusion alleviates systemic inflammation and the cardiac inflammatory response.