Myocardial protection during antegrade versus retrograde cardioplegia

BACKGROUND: It has been suggested that the right ventricular myocardium is suboptimally protected during retrograde blood cardioplegia. METHODS: Twenty patients undergoing an elective coronary bypass procedure were randomized to receive antegrade or retrograde mild hypothermic blood cardioplegia. Transventricular differences in oxygen extraction, lactate production, and pH were monitored during aortic cross-clamping, and myocardial biopsy specimens were taken from both ventricles before cannulation and 15 minutes after aortic declamping for analysis of adenine nucleotides and their breakdown products. The extent of myocardial injury was estimated by monitoring postoperative leakage of troponin T and the MB isoenzyme of creatine kinase. Hemodynamic recovery and postoperative complications were noted. RESULTS: The preoperative characteristics of the two groups were similar. Oxygen extraction and lactate production in the right ventricular myocardium were higher in the retrograde group. In this group, the right ventricle also extracted more oxygen and produced more lactate and acid than did the left ventricle. Tissue levels of adenine nucleotides tended to decrease in both ventricles during operation, with no differences between them. The level of adenosine catabolites did increase somewhat in the right ventricular myocardium of the retrograde cardioplegia group after aortic declamping. There was a tendency for more prominent efflux of troponin T and the MB isoenzyme of creatine kinase in the retrograde group. Nevertheless, the postoperative course was uneventful in both groups. CONCLUSIONS: Retrograde mild hypothermic blood cardioplegia leads to metabolic changes compatible with right ventricular ischemia. Nevertheless, tissue levels of high-energy phosphates are well preserved, and the postoperative course seems to be unproblematic. Care should be taken when retrograde normothermic blood cardioplegia is provided for patients with right ventricular hypertrophy, poor right ventricular function, or severe preoperative myocardial ischemia.     

Haemodynamic evaluation of retrograde versus anterograde delivery of cardioplegic solution in aortic valve replacement

A total of 44 patients undergoing isolated aortic valve replacement received either anterograde (20 patients) or retrograde (24 patients), cold St Thomas's Hospital cardioplegia. The patients were similar with respect to age, sex, left ventricular ejection fraction, left ventricular-aortic pressure gradient, cross-clamping time and mean dose of cardioplegia. After surgery, there were no differences in enzyme release, low cardiac output syndrome, rhythm disturbances or clinical outcome between the two groups. Analysis of the postoperative haemodynamic data, however, suggests better preservation of left ventricular contractility with retrograde delivery of cardioplegic solution.     

The versatility of anterograde/retrograde cardioplegia in heart surgery

Eighty patients underwent open-heart surgery from March 1990 to March 1993. We used combined aortic root (antegrade)/coronary sinus (retrograde) perfusion for cardioplegia delivery as a means of myocardial protection. The special retroplegia cannula was introduced to the coronary sinus (CS) in 67 patients by the transatrial (blind intubation) after one cannula cava insertion; the CS was cannulated under direct vision by right atriotomy after bicaval cannulation in 13 patients. Varied and prolonged cardiac procedures were done using cooled crystalloid cardioplegia (4 centigrades + potassium) except in one patient with severe ventricular damage in whom warm blood cardioplegia was infused. There was no CS or cardiac vein damage or disruption. There was no A-V blockade. The CS was intubated easily in all cases and cardioplegia solution readily infused. Coronary sinus pressure never exceeded 40 mm Hg. Overall hospital mortality (30 days postoperative) was 3.75% (3 cases). Sepsis was the cause of death in 2 patients and stroke in one. Inotropes were used in few cases as a means of renal protection. We conclude that the combined antegrade/retrograde cardioplegia delivery can be used routinely in most patients undergoing open-heart surgery.     

Development of a blood cardioplegia delivery system for children

We have developed a blood cardioplegia delivery system for children. Essential points of a delivery system in pediatric cardiac surgery are (1) a small amount of priming volume of a delivery system, and (2) slow, steady infusion of a cardioplegic solution. We changed a heat exchanger to a smaller one for reduction of priming volume, and changed a roller pump tube to a smaller one for slow, steady infusion. Thus, priming volume of a delivery system has reduced from 180 to 100 ml, and we can infuse a cardioplegic solution at a steady rate less than 10 ml/min. Our clinical experience with this system suggests that this blood cardioplegia delivery system is useful for pediatric cardiac surgery.     

Management of the patient with aortic root disease and aortic insufficiency

There is no single standardized method of repair for the anatomic variations in aortic root pathology, which may include dissection, aneurysmal dilation, and valve disease and can occur at the annulus, sinuses of Valsalva, or the sinotubular junction. Composite valve/graft replacement, valve resuspension, and allograft each play a significant role in aortic root therapy, but none is applicable in all cases. Patient age, Marfan's syndrome, endocarditis, and previous valve replacement are examples of some of the wide variations in delineating factors.     

Stentless xenograft repair of the dissected aortic root

We used a Freestyle (Medtronic, Minneapolis, MN) porcine root to replace a regurgitant aortic valve and repair acute type A dissection. A Hemashield (Meadox Medicals, Oakland, NJ) graft was used to replace the ascending aorta with the "open anastomosis" technique. This method is a valuable alternative to conventional root replacement in acute type A dissection.     

Echocardiographic oscillating flap in aortic root dissecting aneurysm

A patient had a history, physical findings, and chest x-ray film suggesting type I aortic dissection. This diagnosis could not be confirmed angiographically. Echocardiographic studies predicted both the presence of dissection and the anatomic findings at surgery. A regularly oscillating echo corresponding to the intimal flap was found in the false lumen. This is suggested as a new echocardiographic finding in dissecting aneurysm.     

Pseudoabscess of the aortic root caused by ectopic seating of an aortic prosthesis

Twenty-one fetuses with an enlarged fourth ventricle were detected by ultrasound at 14-16 weeks' gestation. No other central nervous system anomalies were observed and a normal size fourth ventricle was noted in all cases on follow-up scans at 22-23 weeks' gestation. Five fetuses had associated structural anomalies: a single umbilical artery in two cases, non-septated cystic hygroma in two cases and ventricular septal defect in one fetus. All fetuses had a normal brain sonogram after delivery. Nineteen newborns who were followed up to the age of one year had no developmental problems. It is concluded that an isolated enlarged fourth ventricle might be a physiological variant in early fetal life.     

Reconstruction of the aortic arch in invasive thymoma under retrograde cerebral perfusion

Extensive en-bloc resection of the aortic arch and anterior wall of the main pulmonary artery was performed in a 46-year-old man with invasive thymoma. The aortic arch was replaced with a Hemashield vascular graft under hypothermic circulatory arrest with retrograde cerebral perfusion. Patch plasty with Xenomedica was performed for the anterior wall of the main pulmonary artery under cardiopulmonary bypass. The patient was treated with postoperative radiotherapy and has remained asymptomatic for 15 months after the operation. An extensive operation is considered necessary to improve the prognosis of invasive thymoma.     

Supraannular aortic root enlargement in patients with small aortic annulus: efficacy and safety

In response to several women who presented with postpartum depression in 1 year, a group of nurses developed a task force made up of hospital nurses, obstetricians, psychiatrists, pediatricians, family practitioners, lactation specialists, home care nurses, and mental health counselors. The purposes of this task force were to educate health care professionals about postpartum depression, to help identify women who might be affected, and to develop interventions for adjusting to parenthood. This article details the evolution of that task force, and how it has assisted not only the women but also the health care providers involved.