Faculty Bibliography

BACKGROUND: During hypothermic blood cardioplegia, oxygen delivery to myocytes is minimal with ineffective anaerobic metabolism predominating. RSR13, 2-[4-[[(3,5-dimethylanilino) carbonyl]methyl]phenoxy]-2-methylpropionic acid, a synthetic allosteric modifier of hemoglobin (Hb), increases release of oxygen from Hb, increasing oxygen availability to hypoxic tissues, and reverses the hypothermia-dependent increase in Hb oxygen affinity. We studied recovery of myocardial mechanical and metabolic function and examined myocardial morphology after cardioplegia, comparing RSR13 (1.75 mmol/L)-supplemented blood (RSR13-BC) to standard blood cardioplegia (BC). METHODS AND RESULTS: Twelve dogs underwent 15 minutes of 37 degrees C global ischemia on cardiopulmonary bypass, followed by 75 minutes of hypothermic cardioplegia (13 degrees C) with either BC (n=6) or RSR13-BC (n=6). There were no differences in baseline function between groups. Cardiac function was assessed after 30 minutes of 37 degrees C reperfusion (BC versus RSR13-BC, respectively) by measuring: % return to normal sinus rhythm (0/100%), % of baseline+dP/dt (33.7+/-1.7/76.3+/-1.9), % of baseline-dP/dt (26.6+/-2.0/81.1+/-1.6), stroke volume (3.5+/-0.5/7.1+/-0.9 mL), cardiac output (340+/-20/880+/-40.3 mL/min), and LVEDP (11.3+/-2.2/0. 3+/-2.9 mm Hg). Postischemic oxidative and metabolic parameters including myocardial lactate, pyruvate, ATP content, and percent water content also were determined. Histological analysis demonstrated preservation of endothelial and myocyte morphology in hearts receiving RSR13-BC compared with BC. CONCLUSIONS: These results indicate that in the setting of hypothermic cardiopulmonary bypass, RSR13 improves recovery of myocardial mechanical and metabolic function compared with standard hypothermic BC. Findings from this study suggest that RSR13-BC, by decreasing hemoglobin oxygen affinity, improves oxidative metabolism and preserves cellular morphology, resulting in significantly improved contractile recovery on reperfusion

BACKGROUND: Following the Norwood procedure for hypoplastic left heart syndrome (HLHS), pulmonary artery distortion and hypoplasia are common and may negatively impact late outcome. The hemi-Fontan procedure (HFP) augments the central pulmonary arteries and establishes a connection between the right atrial/superior vena cava junction and the pulmonary arteries, while excluding the inferior vena cava. METHODS: The hospital records of all 114 patients undergoing a HFP for HLHS between August 1993 and April 1998 were reviewed to assess patient, procedural, and morphologic determinations of outcome. The results of cardiac catheterization, Doppler/echocardiography, 12 lead electrocardiograms, hospital and subsequent course, as well as suitability and outcome for the Fontan procedure were analyzed. RESULTS: Mean age was 5.4 months (range 1.5 to 15 months). Right ventricular function was normal in 95 patients, moderately depressed in 14, and severely depressed in five. Tricuspid regurgitation was absent or mild in 91 patients, moderate in 13, and severe in 10. Concomitant procedures included left superior vena cava to pulmonary artery anastomosis (12), tricuspid valve repair (10), pulmonary artery stent placement (3), coarctation repair (2), and aortic pseudoaneurysm repair (1). Hospital survival was 112/114, 98% (95% confidence interval [CI]: 95% to 100%). There were two late deaths, one noncardiac. Sinus rhythm is present in 105 patients (92%, 95% CI: 87% to 97%). To date, 79 of these patients have undergone the Fontan procedure with 74 survivors (94%, 95% CI: 89% to 99%). CONCLUSIONS: The HFP may be performed with excellent results for HLHS. It effectively augments the central pulmonary arteries while preserving sinus rhythm in the majority. In addition, the HFP facilitates the subsequent Fontan procedure and has significantly improved the overall outcome

OBJECTIVE: Aortic valve atresia or hypoplasia can present with a ventricular septal defect and a normal mitral valve and left ventricle. These patients may be suitable for biventricular repair, although the optimal initial management strategy remains unknown. METHODS: From January 1991 through March 1999, 20 patients with aortic atresia or hypoplasia and ventricular septal defect underwent operation with the intent to achieve biventricular repair. Aortic atresia was present in 7 patients, and aortic valve hypoplasia was present in 13 patients. Among those patients with aortic hypoplasia, Z-scores of the aortic valve anulus ranged from -8.8 to -2.7. Associated anomalies included interrupted aortic arch (n = 12 patients), coarctation (n = 6 patients), aortopulmonary window (n = 1 patient), and heterotaxia (n = 1 patient). Nine patients were staged with an initial Norwood procedure followed by biventricular repair in 8 patients. One patient awaits biventricular repair after a Norwood procedure. The conditions of 11 patients were corrected with a single procedure. RESULTS: Among the 9 patients who underwent staged repair, there were no deaths after the Norwood procedure and 1 death after biventricular repair. For the 11 patients who underwent a primary biventricular repair, there was 1 early death and 2 late deaths from noncardiac causes. Follow-up ranged from 1 to 85 months (mean, 28 months). Actuarial survival for the entire group was 78% +/- 10% at 5 years and was not significantly different between staged repair (89%) and primary biventricular repair (73%). CONCLUSIONS: Both primary and staged biventricular repair for patients with aortic atresia or hypoplasia and ventricular septal defect may be performed with good late survival. Refinements in technique of conduit insertion and arch reconstruction have resulted in primary biventricular repair becoming our preferred approach

Tricuspid valve regurgitation is a common finding in patients with hypoplastic left heart syndrome undergoing staged surgical reconstruction and can result from either abnormal valve morphology or incomplete leaflet coaptation due to annular dilatation. Significant tricuspid insufficiency imposes an additional volume load on the right ventricle and may have an important effect on survival. The spectrum of tricuspid valve anatomy found in hypoplastic left heart syndrome and surgical techniques available for the repair of atrioventricular valves are discussed. Tricuspid valvuloplasty during either the hemi-Fontan or Fontan stages of reconstruction carries a high success rate and is associated with improved right ventricular function.

Patients born with single ventricle and L-transposition of the great arteries present challenging medical and surgical management problems. This defect is characterized by a wide variation in cardiac morphology and physiology. The clinical spectrum can range from cyanosis due to pulmonary outflow obstruction and venoarterial shunting to congestive heart failure from pulmonary over-circulation and systemic outflow tract obstruction. To avoid major operations in ill neonates and infants, earlier surgical treatment strategies concentrated on less invasive procedures that did not require cardiopulmonary bypass. Because of relatively poor initial results and a small number of patients presenting later as good candidates for the Fontan procedure, more elaborate initial palliative operations have been used. Despite their increasing complexity, these procedures more completely address the underlying anatomic and physiologic problems and have accounted for steadily improved patient survival.

This study is a retrospective review using transthoracic echocardiography to assess the success of fenestration closure as well as residual right to left shunts in 35 patients who underwent Fontan fenestration closure in the catheterization laboratory. There is a high rate of closure of the Fontan fenestration; however, other residual right to left shunts are common

BACKGROUND AND OBJECTIVES: Although survival of patients with the hypoplastic left heart syndrome treated by staged surgical palliation has improved, hemodynamic data after fenestrated Fontan operation and after fenestration closure have not been reported in this patient population. We sought to describe the hemodynamic status of these patients at cardiac catheterization performed for the purpose of fenestration closure and to compare these data with data from contemporary patients with other forms of univentricular heart. METHODS AND RESULTS: Hemodynamic responses to fenestration closure during cardiac catheterization were reviewed in 40 consecutive patients, including 20 with the hypoplastic left heart syndrome and 20 with other forms of univentricular heart defects. Hemodynamics before fenestration closure (arterial saturation and pressure, Fontan baffle saturation and pressure, pulmonary capillary wedge pressure, systemic arteriovenous oxygen content difference, and right-to-left shunt fraction) were nearly identical between the two groups. Significant (p < 0.05) changes after fenestration closure included increases in arterial saturation (9%), mean arterial pressure (3 mm Hg), and baffle pressure (1 mm Hg) and arteriovenous oxygen content difference (18 ml/L), with near elimination of right-to-left shunting. Cardiac output decreased by 21% and systemic oxygen transport by 13%, with no differences between the two patient groups. Mean baffle pressures were <17 mm Hg in 32 patients (80%). CONCLUSIONS: Hemodynamics after fenestrated Fontan operation and responses to fenestration closure in patients with the hypoplastic left heart syndrome were remarkably similar to that in patients with other univentricular heart defects

OBJECTIVES: This study evaluated postoperative weight gain in children who received albumin versus crystalloid prime for cardiopulmonary bypass (CPB). DESIGN: A retrospective case-controlled study. Children whose extracorporeal (EC) circuit prime contained albumin (group 1) were matched with those whose prime contained only crystalloid (group 2) on the basis of age, weight, and surgical repair. SETTING: A university-based medical center. PARTICIPANTS: Seventy-six children (newborn to 4 years of age) who underwent CPB for correction of a congenital heart anomaly from 1993 to 1995. Group 1 underwent surgery from October 1994 to September 1995, and group 2 from February 1993 to September 1994. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Group 1 had less weight gain on postoperative days (PODs) 1, 2 and 3 compared with group 2 (p = 0.04 on POD 1). Albumin (grams per milliliter) prime and prime volume in milliliters per kilogram were the best predictors of weight gain (p < 0.004), with prime volume being the more important. Children who weighed less than 7.5 kg received more prime volume and had greater weight gain than children who weighed 7.5 kg or greater on PODs 1, 2, and 3 (p < 0.02). CONCLUSION: Data suggest that adding albumin to the EC circuit prime and minimizing the prime volume will result in less postoperative weight gain. Further prospective study with a larger sample is warranted to determine whether albumin prime offers other clinical benefits