Maldistribution of multidose blood cardioplegia: pharmacologic intervention to prevent subendocardial hypoperfusion by alpha-adrenergic blockade.
Maldistribution of multidose blood cardioplegia (BCP) continues to be a problem causing perioperative subendocardial damage. However, it is not known whether alpha-adrenergic stimulation contributes to the maldistribution of multidose BCP. We have evaluated the effects of phenoxybenzamine (POB) on multidose BCP distribution, with a right heart bypass model in 14 dogs. Although gradual increases in coronary vascular resistance (CVR) were noted in the control group (CP-1: 0.53 +/- 0.08, CP-2: 0.57 +/- 0.07, CP-3: 0.78 +/- 0.10 mm Hg/ml/min/100 g), there was no significant rise in CVR in the POB group (CP-1: 0.36 +/- 0.03, CP-2: 0.37 +/- 0.04, CP-3: 0.42 +/- 0.04 mm Hg/ml/min/100 g). Improved delivery of BCP was observed in the POB group during CP-3 (endo/epicardial flow ratio 1.72 +/- 0.07 vs. 1.21 +/- 0.18 in the control group; p < 0.05). These data indicate that improved delivery of BCP can be obtained by alpha-adrenergic blockade, if multiple injections of BCP are used for cardiac surgery.
Sakakibara
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Department of Surgery, University of Tsukuba, Ibaraki, Japan.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001783:Blood Flow Velocity; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D003331:Coronary Vessels / Q000502:physiology; D004285:Dogs; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006324:Heart Arrest, Induced / Q000379:methods*; D019344:Lactic Acid / Q000096:biosynthesis; D017202:Myocardial Ischemia / Q000378:metabolism / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism; D010643:Phenoxybenzamine / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D014655:Vascular Resistance / Q000502:physiology
D000317:Adrenergic alpha-Antagonists; D002314:Cardioplegic Solutions; D010643:Phenoxybenzamine; D019344:Lactic Acid; D011188:Potassium