Recovery of postischemic contractile function is depressed by antegrade warm continuous blood cardioplegia

To assess the effectiveness of warm antegrade continuous blood cardioplegia in the setting of an acute coronary arterial occlusion, we instrumented 19 Yorkshire swine to quantitate left ventricular global, systolic, diastolic, and regional mechanics. Data were acquired before and after 10 minutes of mid-left anterior descending coronary artery occlusion followed by 60 minutes of aortic crossclamping. Cardiac arrest was induced by the antegrade infusion of 20 ml/kg of warm (37 degrees C) or cold (4 degrees C) oxygenated blood cardioplegic solution followed by either continuous warm (75 ml/min, n = 9) or intermittent cold (10 ml/kg every 20 minutes, n = 10) cardioplegic reinfusions. Left anterior descending coronary artery occlusion was released 20 minutes after aortic crossclamping and resulted in warm-arrested hearts developing a 139% increase in global oxygen consumption compared with values obtained with the left anterior descending coronary artery occluded (p < 0.02). Recovery of global left ventricle contractility, quantitated by the linear preload recruitable stroke-work relationship, was significantly worse after warm cardioplegia (52.4% +/- 5.1% versus 68.0% +/- 5.9%, warm versus cold, p < 0.05). Similarly, left anterior descending coronary artery regional ischemic zone contractility recovered 34.5% +/- 7.3% of control function with cold cardioplegia, whereas warm cardioplegia resulted in -11.36% +/- 7.46% functional recovery indicative of dyssynchronous contraction (p < 0.05). Diastolic compliance, calculated with an exponential end-diastolic pressure-versus-volume relationship, was not changed postischemically in either group. These data suggest that warm antegrade blood cardioplegia may potentiate acute ischemic injury and provide inadequate myocardial protection.