RESUMEN
BACKGROUND: Animal models have suggested that retrograde cardioplegia may be poorly distributed to septal and right ventricular regions of the heart; if true, this may have dangerous implications for warm continuous retrograde cardioplegia in humans. We have previously shown that blood gases from coronary arteries during warm continuous retrograde cardioplegia represent postcapillary "venous" gases and are reflective of myocardial perfusion. METHODS: To determine regional differences in perfusion during warm continuous retrograde cardioplegia we obtained blood gases from three regions of the heart in 141 consecutive patients undergoing coronary artery bypass grafting, aortic valve replacement, or both. Right heart perfusion was determined by blood gases from the right coronary artery orifice, acute marginal, or posterior descending coronary arteries; circumflex or lateral wall perfusion was determined by samples from obtuse marginal or intermediate coronary arteries; and anterior wall/septal perfusion was determined by left anterior descending and diagonal coronary artery blood gases. Warm continuous retrograde cardioplegia flow ranged from 150 to 300 mL/min depending on heart size. A mean of 4 +/- 1 samples/patient were obtained. RESULTS: There were no regional differences in postcapillary pH, carbon dioxide tension, or CO2 production during warm continuous retrograde cardioplegia. Oxygen tensions were lower in the right and anterior/septal regions of the heart, implying more O2 uptake. No regional acidosis, consistent with poor perfusion, could be detected. CONCLUSIONS: We conclude that, unlike experimental models, regional myocardial perfusion, including the right heart, is uniform during "high-flow" warm continuous retrograde cardioplegia in humans.
Asunto(s)
Circulación Coronaria , Paro Cardíaco Inducido , Dióxido de Carbono/sangre , Paro Cardíaco Inducido/métodos , Humanos , Concentración de Iones de Hidrógeno , Oxígeno/sangreRESUMEN
There is a rapid growth of interest in heart transplantation therapy during early infancy. From 10% to 25% of the infants who are listed for transplantation annually have died while awaiting a donor heart. There has been no significant trend in this variable. Since November 1985, 140 consecutive orthotopic transplantation procedures were performed in 139 infants who were from 3 hours to 12 months of age. Indications for transplantation included hypoplastic left heart syndrome (63%), other complex structural anomalies (29%), myopathy (6.5%), and tumors (1.5%). Most recipients had ductus-dependent circulation and received continuous infusion of prostaglandin E1. Heart donors were usually victims of trauma, sudden infant death, or birth asphyxia. A donor-recipient weight ratio of 4.0 or less was found to be acceptable. The amount of time the graft underwent cold ischemia, ranged from 64 to 576 minutes. The procurement process was facilitated by a single dose of cold crystalloid cardioplegic solution and cold immersion transport. Profound hypothermic circulatory arrest was used for graft implantation. One hundred twenty-four (89%) recipients survived transplantation and were discharged from the hospital. There were 9 late deaths, which resulted in an 83% overall survival. The 5-year actuarial survival is 80%. The survival among newborn recipients (n = 60) at 5 years is 84%. Chronic immunomodulation was cyclosporine-based and steroid-free. Surveillance was noninvasive and relied heavily on echocardiography, electrocardiography, and clinical intuition. There was one documented late lethal infection, tumor was not encountered, and coronary occlusive disease was known to exist in only one long-term survivor. We concluded that transplantation results in excellent life quality and is a highly effective and durable therapy when applied during early infancy.