Serafin Y. DeLeon

Choreoathetosis after deep hypothermia without circulatory arrest

In 8 of 758 patients undergoing an intracardiac operation under cardiopulmonary bypass and hypothermia, choreoathetosis developed 3 to 7 days postoperatively. Before the onset of choreoathetosis, varying degrees of neurological dysfunction were noted. Electroencephalography and neuroimaging failed to detect any responsible functional or structural changes. Six patients are alive 1 to 3 years postoperatively, and their condition is improving. Two patients died of aspiration or sepsis. All patients were grouped based on factors identified as being possibly causative: depth of hypothermia, cooling time, flow rate, and repeated hypothermia. The incidence of choreoathetosis was significantly different in group A (rectal temperature greater than 25 degrees C) compared with group B (rectal temperature less than or equal to 25 degrees C) (0/295 versus 8/463; p = 0.02). Based on cooling time, the incidence of choreoathetosis was significantly different in group B1 (cooling time less than 1 hour) compared with group B2 (cooling time greater than or equal to 1 hour) (1/220 versus 7/243; p = 0.05). Based on flow rate during cooling, group B2 was further divided into the low-flow group (less than 1,500 mL.min-1.m-2) and the high-flow group (greater than or equal to 1,500 mL.min-1.m-2). Although not significant, the incidence of choreoathetosis was higher in the high-flow group (6/153 versus 1/90; p = 0.22). In group B patients having reoperation, the incidence of choreoathetosis was higher than in patients operated on for the first time (5/54 versus 3/409; p less than or equal to 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Valve Replacement in Children: Guidelines for Selection of Prosthesis and Timing of Surgical Intervention

One hundred fifty-nine patients ranging from 3 months to 18 years old (mean, 8.1 +/- 3.7 years) underwent 162 primary valve implantations. A porcine valve was used in 104 patients, a St. Jude Medical valve in 40, and a Björk-Shiley valve in 18. The valve replaced was the aortic in 25 patients, the mitral (systemic atrioventricular [AV] valve) in 43, the pulmonary in 71, and the tricuspid (pulmonary AV valve) in 23. Hospital mortality was 6%. Patients with a Björk-Shiley valve received warfarin sodium anticoagulation, and those with a St. Jude Medical valve were given salicylates and dipyridamole. Follow-up is available on all patients 0.6 to 12 years postoperatively (mean, 6.3 +/- 2.6 years). New York Heart Association Functional Class improved in 62% and remained unchanged in 38% of the patients. Thromboembolic complications occurred in only 8 (57%) of 14 patients with a St. Jude Medical valve in the right (pulmonary) side and in 3 (12%) of 26 with the valve in the left (systemic) side of the circulation. Bacterial endocarditis developed in 3 patients, all with porcine valves. Early valve replacement, less than 2 years after detection of hemodynamic deterioration, resulted in improvement in the ventricular ejection fraction in 25 of 29 patients (from 81 +/- 14% to 90 +/- 12% of normal; p less than 0.05). In contrast, the ejection fraction remained abnormal in all 22 patients with delayed valve insertion (more than 2 years) (81 +/- 16% of normal preoperatively and 80 +/- 10% of normal following operation; p = not significant).

Clinical improvement after revision in Fontan patients

BACKGROUND Arrhythmias, decreased exercise tolerance, or malabsorption will develop in a significant number of Fontan patients. Fontan revision consisting of creation of lateral atrial tunnel, reconnection of the Glenn shunt when present, or both appears to improve these patients. METHODS Over a 34-month period, 9 patients underwent Fontan revision. The mean age was 11 +/- 5 years and the mean interval from Fontan operation to revision was 3 +/- 2 years. The reason for revision included marked impairment in exercise capacity, inability to go to school consistently, and chronic fatigue in 6 patients, 3 of whom also had serious atrial arrhythmias. Five of the 6 patients had a classic Glenn shunt. The mean right atrial pressure was greater than the pressure of the Glenn shunt (20 +/- 1.6 versus 17 +/- 0.8 mm Hg). Three of the 6 patients also showed a significant gradient between the right or left pulmonary artery wedge and ventricular end-diastolic pressure, indicating pulmonary vein obstruction from the bulging atrial septum or partitioning patch (13 +/- 3 versus 6.8 +/- 1 mm Hg). The remaining 3 patients had revision because of malabsorption (1), hepatomegaly and obstructed right pulmonary veins from bulging atrial septum (1), and tricuspid insufficiency (1). Fontan revision was accomplished with creation of a lateral atrial tunnel and Glenn reconnection in 6 patients, Glenn reconnection in 2, and creation of a lateral atrial tunnel in 1. Four patients had additional procedures. RESULTS One patient died of Pseudomonas pneumonia. Early extubation, chest tube removal, and postoperative hospital discharge were accomplished in 8 patients (mean = 1.4 +/- 1, 2.8 +/- 1, and 8 +/- 3 days, respectively). One patient died 8 months postoperatively of brain damage after ventricular fibrillation from attempted cardioversion for atrial flutter. The remaining patients had marked improvement in exercise capacity with ability to consistently go to school, improvement in duration and tolerance to arrhythmias on less medication, and resolution of malabsorption up to 37 months postoperatively (mean, 20 +/- 12 months). CONCLUSIONS We conclude that creation of lateral atrial tunnel with excision of a bulging atrial septum or atrial partitioning patch that causes pulmonary venous obstruction, reconnection of the Glenn shunt, which allows better distribution of flow based on the pulmonary vascular bed and resistance of each lung, or a combination of these procedures will improve Fontan patients.

Surgical Management of Infants with Complex Cardiac Anomalies Associated with Reduced Pulmonary Blood Flow and Total Anomalous Pulmonary Venous Drainage

Eight infants with complex cardiac anomalies and pulmonary stenosis or atresia were noted to have obstructed total anomalous pulmonary venous drainage (TAPVD) either at the initial cardiac catheterization (Group 1; n = 2) or after creation of systemic-pulmonary artery shunts (Group 2; n = 6). The 2 patients in Group 1 underwent early repair of TAPVD (1 at 7 days, the other at 1 1/2 months of age) before any subsequent operation and are now doing well at 18 months of age. The 6 patients in Group 2 underwent repeat cardiac catheterization because of persistent severe cyanosis with faint or absent continuous murmur and were found to have patent shunts and obstructed TAPVD (1 mild, 5 severe). One patient who underwent repair of TAPVD at 2 1/2 months of age survived and is well at 2 years of age, whereas 4 patients who underwent repair at an average age of 6 months (age range, 3-16 months) subsequently died. The sixth patient, who did not undergo repair, remained severely cyanotic with hypoplastic pulmonary arteries in spite of repeated shunts. We feel that increased awareness of the possible association of TAPVD and reduced pulmonary blood flow in infants with complex cardiac defects, in combination with echocardiography, oxygen saturation studies, and angiography with prostaglandin E1 challenge, should lead to early diagnosis, avoidance of unnecessary systemic-pulmonary artery shunts, and increased survival rates in these infants.

Transposition of the great arteries: A comparison of results of the Mustard procedure versus the arterial switch

Sixty infants with transposition of the great arteries and intact ventricular septum underwent primary surgical correction in the first 3 months of life. Twenty-three patients had a Mustard procedure (group 1) and 37 patients, an arterial switch operation (group 2). The mean age at the time of repair was 42 +/- 31 days for group 1 and 8 +/- 6 days for group 2 (p less than 0.001). The mean weight at the time of repair was 3.6 +/- 0.7 kg for group 1 and 3.4 +/- 0.5 kg for group 2 (p = not significant). Operative mortality was 8.7% (2/23) in group 1 and 8.1% (3/37) in group 2 (p = not significant). The incidence of arrhythmias in the early postoperative period was 39% (9/23) in group 1 and 11% (4/37) in group 2 (p less than 0.01). All patients were followed a mean of 4.8 +/- 2.4 years in group 1 and 2.6 +/- 1.4 years in group 2 (p less than 0.001). Postoperative catheterization has been performed in 86% (18/21) of group 1 operative survivors and 50% (17/34) of group 2 operative survivors. Ejection fraction of the systemic ventricle was 79% +/- 15% of predicted normal in group 1 and 98% +/- 6% in group 2 (p less than 0.005). The incidence of late arrhythmias was 57% (12/21) in group 1 and 3% (1/34) in group 2 (p less than 0.001). There have been 2 late deaths in group 1 and 1 late death in group 2 (p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical Management of Patients with Interrupted Aortic Arch and Severe Subaortic Stenosis

Ten patients underwent palliative surgery for interrupted aortic arch and severe subaortic obstruction due to posterior displacement of the conal septum. Their ages ranged between 4 and 28 days (mean, 11.0 +/- 7.7 days) and their weights, between 2.1 and 4.2 kg (mean, 2.85 +/- 0.6 kg). Preoperative echocardiography and cardiac catheterization were performed on all patients. The ratios of the left ventricular outflow tract diameters and the ascending aortic diameters to the descending aortic diameters were 0.56 +/- 0.03 and 0.56 +/- 0.06, respectively, compared with 0.81 +/- 0.12 and 0.95 +/- 0.17, respectively, in 20 patients with interrupted aortic arch but without obstruction (p less than 0.001). Four of the 10 patients underwent pulmonary artery banding and insertion of a bypass graft between the ascending and the descending aorta. All 4 died of low cardiac output soon after operation (100% operative mortality). The remaining 6 patients underwent banding and insertion of a graft between the main pulmonary artery proximal to the band, and the descending aorta. All of these patients survived, and all except 1 are doing well 3 months to 4 years postoperatively. The use of a pulmonary artery-descending aorta conduit and of distal pulmonary artery banding provides good palliation for patients with interrupted aortic arch and major subaortic stenosis.

Advantages of early relief of subaortic stenosis in single ventricle equivalents

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 +/- 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 +/- 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 +/- 4.7 mm Hg in group 1 versus 4.7 +/- 5 mm Hg in group 2 (p = 0.002). Ventricular muscle mass was 186% +/- 18% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.0001), and mass/volume ratio was 1.12 +/- 0.62 in group 1 versus 0.62 +/- 0.16 in group 2 (p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 +/- 1.6 years after relief of subaortic stenosis in group 1 and 3.2 +/- 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 +/- 3 mm Hg in group 1 versus 3 +/- 2 mm Hg in group 2 (p = not significant), ventricular muscle mass was 184% +/- 31% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.003), and the mass/volume ratio was 1.17 +/- 0.2 in group 1 versus 0.62 +/- 0.2 in group 2 (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-Term Results of Porcine Valve Insertion for Pulmonary Regurgitation Following Repair of Tetralogy of Fallot

Between January 1975 and January 1985, 49 patients, aged 2 to 20 years, underwent porcine valve insertion for control of pulmonary regurgitation following repair of tetralogy of Fallot. In 9 patients the valve was placed at the time of the repair; in the remaining 40, valve insertion was performed 2 to 5 years postoperatively. The primary indications for valve implantation included progressive cardiomegaly and evidence of right ventricular (RV) dilatation or dysfunction. Operative technique emphasized ample enlargement of the RV outflow tract and main pulmonary artery to allow for insertion of a large valve and prevention of turbulence or stenosis. There was 1 hospital death (2%). Follow-up is available on remaining patients 1 to 10 years postoperatively. Considerable prosthetic valvar stenosis or regurgitation occurred in 7 patients (14%) 3 to 8 years following insertion, including one after subacute bacterial endocarditis. The complication-free actuarial life was 82%, and the functional actuarial life was 84% at 10 years for the prosthesis. The data suggest that the porcine valve has a good long-term durability when inserted in the pulmonary position in pediatric patients.

Surgical options in subaortic stenosis associated with endocardial cushion defects

Over a 15-year period, 12 patients with endocardial cushion defects undergoing correction had subaortic stenosis requiring operative intervention. Ages ranged from 4 months to 17 years (mean, 7 +/- 6 years) and subaortic gradients from 15 to 100 mm Hg (mean, 60 +/- 25 mm Hg). Subaortic stenosis was due to discrete fibromuscular tissues in 7 patients, mitral valve malattachment in 3, and tunnel outflow in 2. In 2, the subaortic stenosis was clinically significant at the time of endocardial cushion defects repair, whereas in 10 it was noted 2 to 14 years postoperatively (mean, 6.3 +/- 5 years). Surgical relief of subaortic stenosis was accomplished by resection of muscle tissues in 7, apicoaortic conduit insertion in 2, modified Konno procedure (aortic valve preserved) in 2, and lifting of malattached mitral valve from the outflow in 1. There was no early death and one late death (infected conduit). Severe mitral insufficiency developed in the patient who had the mitral valve lifted and necessitated valve replacement. Postoperative echocardiographic gradient in 9 patients ranged from 0 to 36 mm Hg (mean, 10.5 +/- 14 mm Hg). Clinically significant subaortic stenosis has not developed in any patient in 15 years of follow-up (mean, 5 +/- 4 years). We conclude that in subaortic stenosis associated with endocardial cushion defects, resection is effective for discrete obstruction, whereas a modified Konno procedure is preferable for obstruction due to tunnel outflow or mitral valve malattachment.

Diaphragmatic pacing in infants: techniques and results.

Phrenic nerve pacing was employed in 8 infants with central hypoventilation syndrome. Their ages ranged from 2.5 to 8.5 months. Preoperative diagnosis was established by demonstrating inadequate ventilatory response to hypercapnia and hypoxia. Percutaneous measurements of phrenic nerve conduction time and diaphragmatic action potentials were performed prior to operation to assess the feasibility of diaphragmatic pacing. A single anterolateral thoracotomy incision was used for both electrode placement in the chest and receiver implantation in the flank. The stimulating electrode was inserted around a segment of intrathoracic phrenic nerve isolated with pleura and perineural blood supply. Follow-up is available on all patients six months to 8 years postoperatively. There were no complications or deaths related to the procedure. In all patients, bilateral phrenic nerve stimulation allowed either marked decrease in or discontinuation of positive-pressure ventilation. Phrenic nerve pacing can be performed safely in infants. It provides an effective alternative method for ventilatory support without the drawbacks of positive-pressure ventilation.