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 ni tric oxide donor can reduce systemic inflammation and the cardiac inflammat ory response during coronary artery bypass grafting with cardiopulmonary by pass. Methods. Patients undergoing elective coronary artery bypass grafting (n = 22) were randomly assigned to treatment with either sodium nitroprusside (0 .5 mu g. kg(-1).min(-1)) or placebo (controls), both for the first 20 minut es of reperfusion. Interleukin-6 and interleukin-8 levels, the adhesion mol ecules CD41 and CD62 on platelets and CD41 on monocytes and PMN (as markers for coaggregate formation), CD11b on monocytes and PMN, as well as platele t and leukocyte counts were determined in radial artery and coronary sinus blood before cardiopulmonary bypass and during reperfusion (1, 5, 10, 25, a nd 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 mi nutes 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 w ith sodium nitroprusside. No intracardiac production of interleukin-8 in so dium 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 min utes of reperfusion) was observed, whereas cardiac production of interleuki n-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 pa ssage in controls (coronary sinus-radial artery difference for CD41-positiv e 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 minute s of reperfusion, 88% +/- 6% and 91% +/- 5%) was compared to washout in tre ated patients (108% +/- 6% and 113% +/- 7%). Conclusions. In patients undergoing routine coronary artery bypass grafting , administration of sodium nitroprusside during early reperfusion alleviate s systemic inflammation and the cardiac inflammatory response.