European Journal of Cardio-Thoracic Surgery, Vol 12, 248-253, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Lipid peroxidation, antioxidant status and troponin-T following cardiopulmonary bypass. A comparison between intermittent crossclamp with fibrillation and crystalloid cardioplegia
AS Cohen, L Hadjinikolaou, A McColl, W Richmond, RA Sapsford and BE Glenville
Department of Cardiothoracic Surgery, St Mary's Hospital, London, UK.
OBJECTIVE: Intermittent crossclamp with fibrillation affords equivalent
myocardial protection to cold crystalloid cardioplegia in patients
undergoing elective coronary artery surgery. This study is a direct
comparison between the two techniques with regards to free radical
activity. METHODS: The study design was part of a prospective randomised
trial. We studied 24 consecutive patients with ejection fraction of 30% or
greater undergoing elective coronary artery surgery. Patients were
randomised into two groups. In group 1 (n = 13) the myocardium was
protected by intermittent aortic cross clamping with fibrillation and group
2 (n = 11) by antegrade cold crystalloid cardioplegia. The determinants of
free radical activity were serial peripheral venous samples for lipid
peroxidation and plasma antioxidant status (before and at 1, 6, 24 and 72 h
after the end of cardiopulmonary bypass). The determinant of the efficacy
of myocardial protection was serial peripheral venous samples of cardiac
troponin-T taken at the same time intervals. RESULTS: The groups were
similar with respect to age, sex distribution, preoperative ventricular
function, left main stem disease, number of grafts and bypass times. Lipid
peroxidation measurements at the 1 h time point were higher than
preoperative values (7.24 +/- 1.19 vs. 4.48 +/- 0.69 and 9.36 +/- 1.46 vs.
4.98 +/- 1.02 (mean +/- S.E) in groups 1 and 2, respectively (units in
mmol/l) thereafter values decreased to near preoperative values by 72 h.
There was no significant difference between the groups (P = 0.42). Total
plasma antioxidant status values at the 1 h time point were lower than the
preoperative values for all patients (1.33 +/- 0.07 vs. 1.63 +/- 0.06 and
1.42 +/- 0.07 vs. 1.63 +/- 0.05 (mean +/- standard error) in groups 1 and
2, respectively, (units in mmol/l) and thereafter at the subsequent time
points increased but never attained their preoperative value. There was no
statistically significant difference between the two groups (P = 0.59).
Troponin-T measurements showed no significant difference between the two
groups at all time points (P = 0.2217). CONCLUSIONS: This study shows that
lipid peroxidation is initially elevated and the defence mechanisms against
oxygen free radicals-antioxidant status'-are depressed following
cardiopulmonary bypass. The degree of oxygen free radical activity produced
during ischaemia and reperfusion was similar in both types of myocardial
protection employed in this study.
