Inflammatory response and myocardial injury following coronary artery bypass grafting with or without cardiopulmonary bypass

Objective: In coronary artery bypass grafting (CABG) without cardiopulmonar y bypass (CPB) the inflammatory response is suggested to be minimized. Coro nary anastomoses are performed during temporary coronary occlusion. Inflamm atory response and myocardial ischaemia need to be studied in a randomized study comparing CABG in multivessel disease with versus without CPB. Method s: Following randomization 30 consecutive patients received CABG either wit h (n = 16) or without CPB (n = 14). Primary study endpoints were parameters of the inflammatory response (interleukin (IL)-6, interleukin-10, ICAM-1, P-selectin) and of myocardial injury (myoglobin, creatine kinase-MB (CK-MB) , troponin I) (intraoperatively, 4, 8, 16, 24 and 48 h after surgery). The secondary endpoint was clinical outcome. Results: The incidence of major (d eath: CABG with CPB n = 1, not significant (n.s.)) and minor adverse events (wound infection: with CPB n = 2, without CPB n = I, n.s.; atrial fibrilla tion: with CPB n = 3, without CPB rt = 2, n.s.) was comparable between both groups. The release of IL-6 was comparable during 8 h of observation (n.s. ). Immediately postoperatively IL-10 levels were higher in the operated gro up with CPB (211.7 +/- 181.9 ng/ml) than in operated patients without CPB ( 104.6 +/- 40.3 ng/ml, P = 0.0017). Thereafter no differences were found bet ween both groups. A similar pattern of release was observed in serial measu res of ICAM-1 and P-selectin, with no difference between both study groups (n.s.). Eight hours postoperativeIy the cumulative release of myoglobin was lower in operated patients without CPB (1829.7 +/- 1374.5 mu g/l) than in operated patients with CPB (4469.8 +/- 4525.7 mu g/l, P = 0.0152). Troponin I release was 300.7 +/- 470.5 mu g/l (48 h postoperatively) in patients wi thout CPB and 552.9 +/- 527.8 mu g/l (P = 0.0213). CK-MB mass release was 3 23.5 +/- 221.2 mu g/l (24 h postoperatively) in operated patients without C PB and 1030.4 +/- 1410.3 mu g/l in operated patients with CPB (P = 0.0003). Conclusions: This prospective randomized study suggests that in low-risk p atients the impact of surgical access on inflammatory response may mimic th e influence of long cross-clamp and perfusion times on inflammatory respons e. Our findings indicate that multiregional warm ischaemia, caused by snari ng of the diseased coronary artery, causes considerably less myocardial inj ury than global cold ischaemia induced by cardioplegic cardiac arrest. (C) 2000 Elsevier Science B.V. All rights reserved.