Faculty Bibliography

OBJECTIVES: Neonates with congenital heart disease may appear hemodynamically stable after operation and then suddenly experience catastrophic decompensation. An improved means of predicting which infants will suddenly die in the early postoperative period may lead to lifesaving interventions. Studies indicate that blood lactate level is proportional to tissue oxygen debt, but information linking lactate levels with outcome in infants after operation is limited. We sought to determine whether a change in lactate level over time was predictive of a poor outcome defined as death within the first 72 hours or the need for extracorporeal membrane oxygenation. METHODS: To test this hypothesis, we studied prospectively 46 infants who were less than 1 month old and were undergoing complex cardiac surgical palliation or repair. Postoperative arterial oxygen saturation, bicarbonate, and lactate levels were recorded on admission to the intensive care unit and every 3 to 12 hours for the first 3 days. RESULTS: Thirty-seven patients had a good outcome, and 9 patients had a poor outcome. Mean initial lactate level was significantly greater in patients with a poor outcome (9.4 +/- 3.8 mmol/L) than in patients with a good outcome (5.6 +/- 2.1 mmol/L; P =.03). However, an elevated initial lactate level of more than 6 mmol/L had a low positive predictive value (38%) for poor outcome. In contrast, a change in lactate level of 0.75 mmol/L per hour or more was associated with a poor outcome (P <.0001) and predicted a poor outcome with an 89% sensitivity value, a 100% specificity value, and a 100% positive predictive value. CONCLUSIONS: Serial blood lactate level measurements may be an accurate predictor of death or the requirement for extracorporeal membrane oxygenator support for patients who undergo complex neonatal cardiac surgery

OBJECTIVE: Previous reports have suggested that prematurity and low birth weight are risk factors for definitive surgical intervention in congenital cardiac malformations. The following data review our experience with primary repair of the complex malformation of aortic arch obstruction with ventricular septal defect (VSD) in this patient population. METHODS: Since 1988, 21 consecutive preterm (</=36 weeks) and/or low birth weight (<3000 g) infants with interrupted aortic arch (IAA; n=10), or aortic coarctation (n=11) with VSD, underwent primary arch repair and VSD closure. The mean weight at operation was 2310 g (range, 1200-2900 g), including 12 patients at </=2500 g. The gestational age ranged from 30 to 41 weeks (mean, 36.4 weeks). Five patients with interrupted arch and two patients with coarctation also had severe subaortic stenosis, which was relieved by transatrial incision of the infundibular septum. RESULTS: The overall hospital mortality was 14% (3/21). Death was related to low cardiac output in association with severe subaortic stenosis (n=2) and sepsis (n=1). Late mortality occurred in three patients, two of which were non-cardiac. The mean follow-up was 33 months. Two patients had significant recurrent arch obstruction, which was successfully relieved by balloon angioplasty and surgical correction in one each. The survival at 30 days, and at 1 and 3 years was 86, 76 and 70%, respectively. CONCLUSIONS: Complete primary repair of aortic arch obstruction with VSD can be achieved with good results, even in the preterm and low birth weight infant. Therefore, early surgical repair of this congenital malformation is recommended

OBJECTIVES: The purpose of this study was to review a large, single institutional experience with the Fontan procedure for patients with hypoplastic left heart syndrome. METHODS: One hundred consecutive patients with 'classic' hypoplastic left heart syndrome underwent Fontan palliation between February 1992 and April 1998. Patient demographic, morphologic, and procedural variables were examined and analyzed. In particular, two different surgical techniques were used: technique I (February 1992 to December 1995) employed cardiopulmonary bypass and moderate systemic hypothermia, and technique II (December 1995 to April 1998), profound hypothermia and circulatory arrest. A retrospective review of medical records was performed and variables were examined and analyzed. RESULTS: Hospital survival for the entire cohort was 89% (95% CI 83%-95%). The technique of operation, cardiopulmonary bypass time, and aortic crossclamp time were each strongly associated with survival. Survival for patients treated by technique I was 79% (95% CI 68-91%; n = 48) and for those treated by technique II, 98% (95% CI 94%-100%; n = 52). Cardiopulmonary bypass and crossclamp times were also highly correlated with time to extubation and length of intensive care unit stay. Preoperative pulmonary artery pressure was correlated with survival; preoperative oxygen saturation, right atrial pressure, pulmonary vascular resistance, pulmonary artery size, extent of aortopulmonary artery collaterals, and echocardiographic estimates of ventricular function and tricuspid regurgitation were not correlated with survival. CONCLUSIONS: Our recent experience with Fontan palliation for patients with hypoplastic left heart syndrome suggests that it is attended by low perioperative mortality. The precise operative technique used appears to be an important determinant of outcome, with the duration of cardiopulmonary bypass and crossclamping being particularly significant

While transvenous defibrillator electrode placement avoiding a thoracotomy is preferable, electrode size, a large intercoil spacing, and the need for subclavicular device placement preclude this approach in most children. We investigated a single RV coil to an abdominally placed active can ICD device. Five children ages 8-16 years (weight 21-50 kg, mean 35 kg) underwent ICD placement. Placement of a single coil Medtronic model 6932 or 6943 electrode was performed via the left subclavian vein approach and the electrode positioned in the RV apex with the coil lying along the RV diaphragmatic surface. The ICD (Medtronic Micro Jewel II model 7223 Cx) was implanted in a left abdominal pocket with the lead tunneled from the infraclavicular region to the pocket. Implant DFTs were < or = 15 J using a biphasic waveform. DFTs rechecked within 3-month postimplant were unchanged. Lead impedance at implant ranged from 38 to 56 omega, mean 51 omega. Follow-up was 3-21 months (total 82 months) with no electrode dislodgment, lead fractures, or inappropriate discharges. Two of the five patients have had successful appropriate ICD discharges. Transvenous ICD electrode placement can be performed in children as small as 20 kg with the device implanted in a cosmetically acceptable abdominal pocket that is well tolerated. Excellent DFTs can be achieved. This approach avoids a thoracotomy in all but the smallest child, does not require subclavicular placement of the device, and avoids use of a second intravascular coil

Development of a mycotic aneurysm or pseudoaneurysm after subacute bacterial endarteritis is uncommon. Nonetheless, patients with coarctation of the aorta are more likely to develop this complication. We describe a case of a large pseudoaneurysm discovered in a child with a previously undiagnosed aorta coarctation. Successful repair was performed with the aid of partial left heart bypass and the use of an interposition graft. A high index of suspicion is necessary to accurately diagnose this rare but life-threatening entity

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.