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Circulating Homocysteine and Copper Following Coronary Artery Bypass Graft Surgery with and Without Cardiopulmonary Bypass
Author(s) -
Shukla N,
Jeremy JY,
Handley A,
Talpahewa SP,
Capoun R,
Angelini GD,
Ascoine R
Publication year - 2002
Publication title -
journal of cardiac surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 58
eISSN - 1540-8191
pISSN - 0886-0440
DOI - 10.1046/j.1540-8191.2002.101425.x
Subject(s) - medicine , cardiopulmonary bypass , homocysteine , vitamin b12 , artery , cardiology , off pump coronary artery bypass , surgery , anesthesia , bypass grafting
Aim: The vasculopathic impact of homocysteine (HCy) is mediated through the generation of superoxide, a phenomenon augmented by copper (Cu 2+ ). Cardiopulmonary bypass (CPB) also elicits oxidant stress. Since oxygen free radicals may play a role in both early and late vein graft failure, the blood levels of HCy and Cu 2+ and related parameters, before and after surgery, were investigated in patients undergoing coronary artery bypass graft surgery (CABG), both with (on pump) and without CPB (off pump). Methods: Blood samples were taken from 20 consecutive patients (10 on‐pump and 10 off‐pump) undergoing CABG, one day pre‐operatively (D0) and one day (D1) and six days (D6) post‐operatively. Plasma HCy, serum Cu 2+ , caeruloplasmin (CP) and vitamin B 12 and red cell folate were then measured. Results: Pre‐operative (D0) plasma concentrations of HCy were below the accepted risk factor value of 14 μmol/l. At D1 there was a reduction in all parameters in both groups, which is ascribable to hemodilution. However, in both on pump and off pump groups, HCy, Cu 2+ and CP were all significantly increased at D6. Concentrations of red cell folate were not significantly altered and serum vitamin B 12 was significantly increased at D6, indicating that the increase in HCy was not due to a reduction in these vitamins. When comparing on‐pump to off pump, there were no significant differences between any parameter except for Cu 2+ which was significantly greater in the on pump group compared to the off pump group at D6. 1 Circulating Parameters Following CABG (Means ± SEM;n = 10)*p < 0.05vs Pre‐Operative Levels and# p < 0.05on Pump vs Off PumpHCy (μmol/l)Cu 2+ (μmol/l) CP (g/l) Folate (mg/l)VitB 12 (ng/l)On pump: D0 10.5 ± 1.313.9 ± 3.20.30 ± 0.05388 ± 182261 ± 75Off pump: D0 9.8 ± 1.213.6 ± 3.30.35 ± 0.12340 ± 78240 ± 140On pump: D1 9.2 ± 1.410.5 ± 3.20.23 ± 0.10357 ± 168170 ± 62Off pump: D1 8.7 ± 1.313.2 ± 2.80.32 ± 0.10351 ± 84190 ± 89On pump: D6 12.7 ± 1.2*21.9 ± 2.5* #0.40 ± 0.04*394 ± 150410 ± 160*Off pump: D6 11.1 ± 1.3*19.0 ± 2.6*0.40 ± 0.07*331 ± 57385 ± 169*Conclusions: Contrary to other reports, the pre‐operative plasma concentrations of HCy in this study suggest that HCy is not a risk factor for coronary artery disease. However, following CABG, the significant increase in HCy and Cu 2+ may be of pathological importance since Cu 2+ augments the release of superoxide from HCy. The greater increase in serum Cu 2+ in the on‐pump group indicates that CPB may promote oxidant stress through elevation of this potent transition metal.