Myocardial protection using diadenosine tetraphosphate with pharmacological preconditioning

Background. We have reported a similar cardioprotective effect and mechanis m of diadenosine tetraphosphate (AP4A) and ischemic preconditioning in rat hearts. In this study, the applicability of AP4A administration to cardiac surgery was tested by using a canine cardiopulmonary bypass model. Methods. Hearts underwent 60 minutes of cardioplegic arrest (34 degrees C) by a single dose of cardioplegia. Cardioplegia contained either AP4A (40 mu mol/L; n = 6) or saline (n = 6). Beagles were weaned from cardiopulmonary bypass 30 minutes after reperfusion, and left ventricular function was eval uated after another 30 minutes by using the cardiac loop analysis system. Results. Administration of AP4A significantly improved the postischemic rec overy of cardiac function and reduced the leakage of serum creatine kinase compared with saline. Systemic vascular resistance, mean aortic blood press ure, and the electrocardiographic indices were not significantly altered by AP4A administration. Conclusions. Administration of AP4A was cardioprotective without apparent a dverse effects. Because the cardioprotective mechanism may be similar to th at of ischemic preconditioning, the addition of AP4A into cardioplegia may be a novel safe method for clinical application of preconditioning cardiopr otection. (Ann Thorac Surg 2000;70:901-5) (C) 2000 by The Society of Thorac ic Surgeons.