Off-pump coronary bypass grafting to double vessel disease with the pharmacological assist of esmolol. An experimental study.
BACKGROUND
To demonstrate the surgical efficacy and safety of off-pump coronary bypass grafting to double- or triple-vessel disease, we performed off-pump double bypass grafting using a brief local coronary occlusion with the pharmacological assist of esmolol.


METHODS
These experiments were conducted in 30 canine hearts with the left internal thoracic artery (ITA) grafted to the circumflex coronary artery (CFX) and the right ITA grafted to the left anterior descending coronary artery (LAD), off pump, using a brief local coronary occlusion through the left minithoracotomy. The coronary anastomosis was performed using a brief local occlusion of the coronary artery. An anastomosis between the left ITA and the CFX was done first, and then the right ITA and the LAD were anastomosed. Thirty animals were divided into 2 groups, group A (n=15) receiving esmolol just before (10 mg/kg on a bolus) and during the coronary artery occlusion (500 microg/kg/min continuously), and group B (n=15) without administrating esmolol as a control.


RESULTS
Operative deaths were 4 in group B and all of group A animals survived (p<0.05). All deaths were attributable to ventricular arrhythmias during/after coronary occlusion. Group B animals necessitating longer coronary occlusion time (more than 15 min) were more likely to fibrillate and more difficult to resuscitate than group A animals requiring coronary occlusion time more than 15 min. Segmental shortening on the echocardiogram demonstrated no significant difference between group A and B in both anterior and posterior wall segment. However, echocardiogram in animals necessitating coronary occlusion time more than 15 min demonstrated that segmental shortening in group A were better than in group B (18 vs 11%, p<0.05), and comparatively greater but not significant in the posterior wall (19 vs 14%).


CONCLUSIONS
The use of esmolol may be recommended to off-pump coronary bypass even to the double-vessel bypass, in order to make off-pump approach safer.
Otaki
M
M
Department of Cardiac Surgery, Kinki University Hospital, Osaka, Japan.
Ogawa
T
T
Inoue
T
T
Oku
H
H
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000818:Animals; D002315:Cardiopulmonary Bypass; D023921:Coronary Stenosis / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography; D007387:Internal Mammary-Coronary Artery Anastomosis; D011412:Propanolamines / Q000627:therapeutic use*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; C036604:esmolol