Does off-pump revascularization reduce coronary endothelial dysfunction?
BACKGROUND
Off-pump coronary revascularization (OPCAB) has been shown to reduce markers of acute inflammation but its effect on coronary endothelial function is unknown. This experimental study sought to determine whether OPCAB reduces endothelial dysfunction, compared to standard cardiopulmonary bypass (CPB) with and without the anticomplement agent soluble complement receptor-1 (sCR(1)).


METHODS
In 10 pigs, OPCAB was simulated by snaring the left anterior descending (LAD) artery for 15 minutes followed by 3 hours of reperfusion. On-pump revascularization was simulated in 20 pigs by 15 minutes of LAD occlusion on CPB with cold blood cardioplegic arrest followed by 3 hours of reperfusion. Ten of these animals received sCR(1) (10 mg/kg) prior to CPB. Inflammatory response was monitored by percent (%) lung water increase, wall motion scores (WMS) with transthoracic echocardiography where 4 = normal to -1 = dyskinesia, and endothelial function in the distal LAD with bradykinin-induced coronary artery relaxation using organ chamber methodology.


RESULTS
OPCAB had no effect on lung edema (% increase = 1.7 +/- 1.4 OPCAB vs. 3.4 +/- 0.5 CPB vs. 2.3 +/- 0.9 CPB + sCR(1)) and failed to prevent wall motion changes (WMS = 2.65 +/- 0.08 OPCAB vs. 2.70 +/- 0.04 CPB vs. 3.10 +/- 0.07* CPB + sCR(1), *p < 0.01) and coronary endothelial dysfunction (% relaxation = 41 +/- 9 OPCAB vs. 40 +/- 9 CPB vs. 78 +/- 8** CPB + sCR(1), **p < 0.001), which was best preserved with sCR(1).


CONCLUSIONS
This study suggests that agents which directly inhibit complement activation such as sCR(1) are more important in preventing endothelial dysfunction during coronary revascularization than merely avoiding CPB.
Lazar
Harold L
HL
Department of Cardiothoracic Surgery, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA. harold.lazar@bmc.org
Bao
Yusheng
Y
Rivers
Samuel
S
D000818:Animals; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D003169:Complement Inactivator Proteins / Q000276:immunology; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000209:etiology* / Q000601:surgery*; D004730:Endothelium, Vascular / Q000276:immunology*; D023421:Models, Animal; D011951:Receptors, Complement / Q000276:immunology; D013552:Swine
D003169:Complement Inactivator Proteins; D011951:Receptors, Complement; C082885:soluble complement inhibitor 1