Absence of myocardial release of troponin T after coronary bypass surgery on a beating heart.
BACKGROUND
Coronary artery bypass grafting (CABG) operations in connection with cardiopulmonary bypass (CPB) appear to be associated with a number of side effects including trauma, cognitive dysfunction and myocardial damage. Accordingly, a current interest in performing CABG on a beating heart begins to emerge. This study examines the premise that conducting CABG on a beating heart limits the extent of myocardial injury and other complications.


METHODS
Forty-five consecutive patients underwent CABG on a beating heart (group A, 12 patients) or in connection with CPB (group B, 33 patients). Inclusion criteria were poor left ventricular function and evolving myocardial ischemia or infarction. Results were assessed primarily on the basis of clinical outcome. In addition, measurement of plasma levels of troponin T (TnT), creatine kinase MB (CK-MB) and lactate dehydrogenase (LD) was conducted in 12 patients of group A preoperatively and 24 h after completion of surgery. These biological data were compared with those from control patients who underwent CABG in connection with CPB within the same time span.


RESULTS
All patients in groups A and B survived the CABG procedure and those on a beating heart maintained an excellent perioperative hemodynamic measurements. The mean bypass time was 75 +/- 21 min and the mean cardiac standstill was 40 +/- 17 min. The intensive care unit stay was for group A: 18 +/- 4 h, group B: 48 +/- 12 h; and the total hospital stay was for group A: 6 +/- 1 days, group B: 8 +/- 3 days. Angiographic studies showed good anastomatic patency in both groups. Postoperative low output syndrome as indicated by the need of ionotropic drugs for more than 24 h was demonstrated in 4% and 6% of groups A and B, respectively. Limitation of myocardial injury in group A was demonstrated by the minimal increase in postoperative TnT levels (16.0 +/- 0.9 versus 30 +/- 8.0 pg/ml). A similar pattern of changes was observed with other infarction markers including CK-MB and LD. Contrastingly, the pre- and post-operative values of TnT in group B were 18 +/- 1.6 and 790 +/- 140 pg/ml, respectively.


CONCLUSIONS
CABG on a beating heart shares many of the positive features of CPB with a distinct advantage of eliminating the intraoperative myocardial ischemia.
Takriti
S A
SA
Al-Assad University Hospital, Syria.
Hindaoui
R
R
Jouma
M
M
Bitar
M S
MS
D000328:Adult; D001026:Coronary Artery Bypass / Q000379:methods; D003327:Coronary Disease / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood; D009206:Myocardium / Q000378:metabolism*; D011184:Postoperative Period; D020107:Troponin T / Q000378:metabolism*
D020107:Troponin T