Retrograde continuous warm blood cardioplegia: maintenance of myocardial homeostasis in humans.

Recent clinical reports have suggested that continuous delivery of oxygenated warm blood cardioplegia through the coronary veins (retrograde cardioplegia) produces good myocardial preservation during aortic cross-clamping. No data exist, however, about actual myocardial metabolism/homeostasis during retrograde warm blood cardioplegia. We studied 100 consecutive patients undergoing coronary artery bypass grafting, aortic valve replacement, or both who received retrograde continuous warm blood cardioplegia (4:1 dilution) during aortic cross-clamping for 54 to 174 minutes. We measured pH, oxygen tension, carbon dioxide tension, HCO3, base excess, and oxygen content of the inflow cardioplegia and the blood egressing from coronary arteries during each arteriotomy for bypass grafting (arteries act as postcapillary veins with retrograde cardioplegia) or the left and right coronary orifices during aortic valve replacement. We also measured these variables from the coronary sinus effluent 1 minute after release of the aortic cross-clamp. Retrograde cardioplegia flow ranged from 50 to 250 mL/min (mean flow, 150 mL/min). All patients were maintained at normothermia during bypass. A total of 460 samples were analyzed (4.6 per patient). Neither the duration of aortic cross-clamping nor the artery sampled affected myocardial blood gases. The pH dropped from 7.41 +/- 0.05 for the inflow cardioplegia to 7.32 +/- 0.1 when sampled from coronary arteries, and the oxygen tension fell from 181 +/- 25 to 28 +/- 5 mm Hg, respectively. Carbon dioxide tension rose from 31.0 +/- 4.1 to 41.4 +/- 9.8 mm Hg. Coronary sinus blood gases 1 minute after cross-clamp removal showed no acidosis or oxygen debt.(ABSTRACT TRUNCATED AT 250 WORDS)

Optimal delivery of cardioplegic solution for "redo" operations.

Increasing experience suggests that retrograde cardioplegia offers several benefits during cardiac reoperations. However, the need for dissection to allow caval snares for open coronary sinus intubation or to palpate the atrioventricular groove for transatrial coronary sinus intubation may disturb diseased vein grafts or require more dissection than necessary. Although antegrade-retrograde techniques can be used, antegrade cardioplegia risks atheromatous embolization from old vein grafts. To optimize delivery of cardioplegic solution, we designed and used "no touch" transatrial intubation of the coronary sinus for retrograde delivery of cardioplegic solution in 63 consecutive patients aged 20 to 87 years (mean 68 years) undergoing 36 redo coronary bypass operations, 7 combined redo coronary bypass/valve replacements, 6 redo aortic valve repairs/replacements, 6 redo mitral valve repairs/replacements, 4 redo double valve repairs/replacements, 2 redo triple valve repairs/replacements, and 2 redo composite aortic valve and arch replacements. "No touch" coronary sinus cannulation was achieved by minimally dissecting the aorta and high right atrium enough for two purse-string sutures. No attempt was made to dissect the junction of the inferior vena cava and atrioventricular groove if old vein grafts were present. The distal pressure line of the Gundry DLP RCSP retrograde cardioplegia cannula (DPL, Inc., Grand Rapids, Mich.) was connected to a transducer, flushed, and then introduced into the right atrium. The pressure tracing thus obtained was observed while the catheter was advanced, using its curved stylet, "blindly" without touching the heart, through the right atrium into the coronary sinus until a coronary sinus waveform was obtained (similar to floating a thermodilution catheter). The catheter's distal balloon was then inflated to occlude the coronary sinus momentarily. A rise in sinus pressure confirmed placement. If pressure did not rise, the cannula was usually in the right ventricle and was repositioned. All coronary sinuses were successfully intubated blindly. Bypass was then instituted, the aorta crossclamped, and the proximal aorta vented. Old vein grafts were cut at the aorta before retrograde cardioplegia was begun; atheromatous material was routinely flushed retrogradely from vein grafts. Only after arrest were hearts dissected as needed. Antegrade cardioplegia was not used. There were two (3%) deaths, both from hospital-acquired pneumonia, no perioperative myocardial infarctions, and no episodes of heart block. Inotropic agents were used in six of 63 patients (10%). We conclude that "no touch" transatrial retrograde cardioplegia offers optimal, simplified myocardial protection for cardiac reoperations, permits arrest of the heart before cardiac manipulations, and expands the use of retrograde cardioplegia by obviating cardiac dissection.

Aggressive peritoneal dialysis for treatment of acute kidney failure after neonatal heart transplantation.

Many infants with hypoplastic left heart syndrome are now treated with heart transplantation. Preoperative or postoperative systemic/renal hypoperfusion occurs frequently, however, resulting in perioperative kidney failure. Of 45 neonates undergoing heart transplantation at our institution, we report on 10 (22%) who required postoperative peritoneal dialysis. Patients' age at transplantation ranged between 1 and 31 (mean, 16.7) days, average weight was 2912 (range, 2140 to 3664) gms. Peritoneal dialysis was started at a mean of 51 hours after transplantation for treatment of anuria (5 patients, 50%), oliguria (3 patients, 30%), fluid overload or hyperkalemia (1 patient each, 10%) and continued for a mean of 101 +/- 90.5 (range, 33 to 270) hours. The value for blood urea nitrogen fell from 46.7 +/- 15.6 mg/dl to 14.3 +/- 10.5 mg/dl, and serum creatinine levels decreased from 2.4 +/- 1.0 mg/dl to 0.6 +/- 0.3 mg/dl throughout peritoneal dialysis. All patients continued to receive cyclosporine during dialysis. Hyperglycemia developed in four patients. Five of 10 patients had ongoing sepsis during dialysis, but only one died while on dialysis (10%). Two patients died late, after peritoneal dialysis was discontinued. Follow-up ranges from 2 months to 5 years. At most recent follow-up, mean creatinine level was 0.5 +/- 0.1 mg/dl. We conclude that aggressive peritoneal dialysis may result in high salvage rates with low morbidity, without the need to discontinue cyclosporine in the setting of neonatal heart transplantation and acute kidney failure.