On-pump beating heart versus off-pump coronary artery bypass surgery-evidence of pump-induced myocardial injury.
OBJECTIVE
By maintaining native coronary blood flow in on-pump beating heart surgery (OnP-BH) and comparing with OPCAB strategy pump-related effects on myocardial injury and cardiac dysfunction could be specifically differentiated from ischemia/reperfusion-related consequences of surgical coronary revascularization.


METHODS
In a randomized-prospective design, 40 elective patients with normal EF and three vessels coronary artery disease (left main disease excluded) were assigned to OPCAB or OnP-BH surgery. Before coronary occlusion and 1, 30, 60, and 90 min after reperfusion with the LIMA graft, coronary sinus (CS) blood was sampled to determine intraoperative myocardial ischemia (pH, lactate, pO2) and oxidative stress (malondialdehyde, MDA). Additionally to CS blood arterial blood was analyzed 4, 12, and 24 h postoperatively to determine myocardial necrosis (CK-MB, cardiac troponin I), myocardial dysfunction (NT-proBNP) and inflammation (C-reactive protein).


RESULTS
Groups were identical with regards to age and gender (OPCAB 63.0+/-6.0 versus OnP-BH 65.3+/-3.9 y, 20% female patients). Number of grafts were 3.0+/-0.5 in OPCAB versus 2.9+/-0.3 in OnP-BH (n.s.) with 44 versus 34% bilateral IMAs and 56 versus 50% complete arterial revascularization. Regarding ischemia, intraoperatively only lactate values increased significantly in the OnP-BH group. Significantly higher CK-MB and troponin I levels were found from LIMA-LAD flow release onwards to 4 h postoperatively in the OnP-BH group. NT-proBNP levels were significantly higher in the OnP-BH group during the entire study period. CRP levels were higher in the OnP-BH group 12 and 24 h postoperatively.


CONCLUSIONS
In this randomized study on routine coronary patients with normal ventricular function, OPCAB revealed less myocardial injury than OnP-BH. These findings implicate that CPB slightly affects the myocardium.
Rastan
Ardawan Julian
AJ
Department of Cardiac Surgery, University of Leipzig, Heart Center Leipzig, Struempellstr. 39, 04289 Leipzig, Germany. rastan@rz.uni-leipzig.de
Bittner
Hartmuth Bruno
HB
Gummert
Jan Fritz
JF
Walther
Thomas
T
Schewick
Claudia V
CV
Girdauskas
Evaldes
E
Mohr
Friedrich Wilhelm
FW
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000295:instrumentation; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects; D003327:Coronary Disease / Q000097:blood / Q000601:surgery*; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007431:Intraoperative Complications / Q000175:diagnosis / Q000209:etiology; D007527:Isoenzymes / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000209:etiology; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010100:Oxygen / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D019210:Troponin I / Q000097:blood
D015415:Biomarkers; D007527:Isoenzymes; D010446:Peptide Fragments; D019210:Troponin I; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D019344:Lactic Acid; D002097:C-Reactive Protein; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form; D010100:Oxygen