Role of endomyocardial biopsy in rejection surveillance after heart transplantation in neonates and children.

OBJECTIVES: The aim of this study was to retrospectively evaluate the sensitivity of noninvasive surveillance (physical examination, echocardiography) of rejection in accurately predicting histologically documented rejection episodes. Additionally, the usefulness of routine scheduled biopsy and its safety in pediatric patients was explored. BACKGROUND: Endomyocardial biopsy has been utilized as the standard for rejection surveillance after heart transplantation in adults, but its role in documenting clinically suspected rejection and in routine surveillance of pediatric patients has not been agreed upon. METHODS: Heart transplantation was performed in 14 neonates and 21 children. The immunosuppressive regimen consisted of cyclosporine, azathioprine and prednisone. All patients underwent routine noninvasive rejection surveillance that included clinical examination and echocardiography. In the neonates, biopsy was performed quarterly beginning 6 months after transplantation, after cessation of prednisone therapy. In the children, biopsy was performed 15 times in the 1st year. A minimum of five biopsy samples were interpreted using the Working Formulation for Heart Transplant Rejection. RESULTS: In the neonates, 37 biopsies were performed. Evidence of rejection was present in only three biopsy samples obtained during eight episodes (38%) of clinically suspected rejection. In 29 biopsies performed when rejection was not clinically suspected, each biopsy was free of cellular infiltrate. In the children, 291 biopsies were performed. Evidence of rejection was present in only seven biopsies (41%) from 17 episodes of clinically suspected rejection. Cellular rejection was discovered during routine rejection surveillance biopsies in asymptomatic patients in 23 (8.4%) of 274 biopsies. CONCLUSIONS: In neonates with clinically suspected rejection, endomyocardial biopsy identified which patients did not require rejection therapy. Endomyocardial biopsy surveillance did not detect any unsuspected cases of rejection. In children, noninvasive rejection surveillance was less reliable even in asymptomatic patients, suggesting that periodic endomyocardial biopsy should be utilized.

Clinical and electrophysiologic features of fetal and neonatal paroxysmal atrial tachycardia resulting in congestive heart failure.

Those clinical and electrophysiologic features of paroxysmal atrial tachycardia (PAT) that appeared to be the cause of prenatal congestive heart failure (CHF) (hydrops fetalis) were evaluated in 12 neonates, ages 1 to 14 days, and compared with those occurring in 12 neonates, ages 2 to 34 days, who developed CHF from PAT diagnosed postnatally. Transesophageal electrophysiologic evaluation was performed after birth or at the time of PAT occurrence in the prenatal CHF group and at the time of CHF diagnosis in the postnatal CHF group. Before the electrophysiologic study, spontaneous PAT onset and termination were observed in all prenatal CHF neonates. In the postnatal CHF neonates, however, a single, prolonged episode of PAT was observed. During PAT, all neonates were observed to have a regular heart rate, normal QRS morphology and ventriculoatrial interval exceeding 80 ms. These findings suggested an orthodromic reciprocating tachycardia using an accessory atrioventricular connection as the tachycardia mechanism. In the 12 neonates with prenatal CHF, the PAT cycle length measured 243 +/- 30 ms, whereas in the 12 neonates with postnatal CHF it measured 208 +/- 19 ms (p less than 0.003). Neonates with prenatal CHF secondary to PAT appear to develop CHF from multiple PATs recurring at relatively long cycle lengths (slow heart rates), whereas postnatal CHF neonates develop heart failure symptoms during a sustained tachycardia episode with relatively short cycle lengths (fast heart rates).

Anomalous origin of the left coronary artery. A twenty-year review of surgical management.

Children with anomalous origin of the left coronary artery from the pulmonary artery are at risk for myocardial infarction and death. Surgical management of this condition in children has evolved significantly during the past 20 years. Between 1970 and 1990, a total of 20 of these patients underwent surgical intervention at two institutions. Age at operation ranged from 3 weeks to 11 years (mean, 26 months). Twelve patients had congestive heart failure, three were in cardiogenic shock, and two had cardiac murmurs. Operative techniques included ligation (n = 9), subclavian artery anastomosis (n = 5), aortic implantation (n = 3), internal mammary artery anastomosis (n = 1), intrapulmonary tunnel from aortopulmonary window to coronary artery (n = 1), and cardiac transplantation (n = 1). The three deaths in the series occurred at 3 weeks, at 2 months, and at 9 years after ligation. There have been no deaths after establishment of a two coronary artery system or after transplantation. Two of the five patients who had subclavian artery anastomosis to the anomalous coronary artery have severe anastomotic stenosis and collateralization. For patients with anomalous origin of the left coronary artery from the pulmonary artery, we recommend direct aortic implantation of the anomalous coronary artery at the time of diagnosis. Intrapulmonary tunnel from aortopulmonary window to coronary artery, or aorta-coronary bypass with internal mammary artery are recommended for children in whom aortic implantation is not anatomically feasible. Left coronary artery ligation is not indicated for these patients; those who have survived ligation should be considered for elective establishment of a two coronary artery system because of the risk of late death.

Exit block in pediatric cardiac pacing. Comparison of the suture-type and fishhook epicardial electrodes.

Ninety-seven consecutive permanent epicardial pacemaker implantations were performed with either suture-type (group I, n = 52) or fishhook electrodes (group II, n = 45). In addition to epicardial fixation of the electrodes at the collar area, the suture-type was further secured in place by tying the electrode's suture at its exit to another nonabsorbable pledget-supported suture. Acute thresholds and slew rates were not significantly different between the two groups. Although the R wave was lower in group I (8.4 +/- 3.5 mV) than in group II (11.8 +/- 6, p less than 0.01), no sensing problems occurred. The larger surface area of suture-type electrode led to lower resistance in group I (271 +/- 61 omega) compared with group II (356 +/- 72, p less than 0.001); however, the difference in pacemaker generator longevity did not appear significant (group I, n = 12, mean 4.7 +/- 1.6 years; group II, n = 4, mean 5 +/- 0.6 years). The incidence of exit block was significantly higher in group II (40%, 18/45) than in group I (8%, 4/52, p less than 0.01). The length of the stimulation tip and better fixation of the suture-type electrode probably accounted for the observed difference in the incidence of exit block between the two electrodes.

Surgical management of the conal (supracristal) ventricular septal defect.

Surgical management of the conal (supracristal) ventricular septal defect differs significantly from the management of the perimembranous (infracristal) ventricular septal defect. The absence of a portion of the conal septum can lead to prolapse of the right cusp of the aortic valve, which predisposes these patients to aortic insufficiency. Between January 1980 and December 1989, 36 children with conal ventricular septal defect underwent intracardiac repair. Diagnosis was by echocardiography, cardiac catheterization, and intraoperative exploration. Preoperative evaluation showed that 26 patients (72%) had aortic valve prolapse and 16 (44%) had aortic insufficiency. Pulmonary-to-systemic flow ratios ranged from 1:1 to 3.5:1 (mean 2.0:1.0). Ten patients (27%) were believed to have clinical congestive heart failure. Age at the time of operation ranged from 2 weeks to 18 years (mean 5.5 years). Operative exposure was through the pulmonary artery (26), aorta (4), right ventricle (3), or right atrium (3). Simultaneous aortic valve suspension for aortic insufficiency was performed in four patients. Operative survival was 100%. Follow-up is complete in all patients and ranges from 0.5 to 9 years (mean 4.3 years). All patients are in normal sinus rhythm. No residual ventricular septal defects have been identified. Twenty-three of 36 patients (64%) have no evidence of aortic insufficiency; 12 of 36 (33%) have trivial or mild aortic insufficiency. One patient with initial severe aortic insufficiency underwent repeat aortic valvuloplasty 3 years after ventricular septal defect closure and aortic valve suspension. No patients have required aortic valve replacement. Surgical management of the conal ventricular septal defect differs from that of the perimembranous ventricular septal defect in two critical aspects. The operative approach should be through the pulmonary artery. This allows the best exposure of the remaining conal septum and the pulmonary and aortic valve leaflets, facilitating closure of the defect without injury to the valves or conduction system. Conal ventricular septal defects should undergo early closure, regardless of shunt volume, to prevent progressive aortic insufficiency.

An alternative approach to the surgical management of physiologically corrected transposition with ventricular septal defect and pulmonary stenosis or atresia.

A modified approach to the surgical management of corrected transposition of the great vessels with ventricular septal defect and pulmonary stenosis or atresia was used successfully in two patients. The procedure consisted of performing a venous switch operation, directing the blood flow from the morphologically left ventricle (right-sided chamber) into the aorta through the ventricular septal defect and inserting a valved conduit between the left-sided morphologically right ventricle and the pulmonary artery. This approach has several advantages when compared with the traditional surgical management, which consists of closure of the ventricular septal defect and a left ventricular (right-sided chamber) to pulmonary artery conduit. It uses the morphologically left ventricle as the systemic pumping chamber, thereby minimizing long-term ventricular failure. It allows closure of the defect from the right ventricular side of the septum, thus decreasing the prevalence of complete atrioventricular block. It also avoids use of the tricuspid valve as the systemic atrioventricular valve and therefore decreases the chance of postoperative valve regurgitation.

Intermediate term results of infant orthotopic cardiac transplantation from two centers.

Orthotopic cardiac transplantation has become established for selected infants with severe forms of congenital heart disease. This study reviews the combined experience and intermediate term results of infants undergoing orthotopic cardiac transplantation from Children's Memorial Hospital, Chicago, and Kosair Children's Hospital, Louisville. From June 1986 through December 1989, 20 orthotopic cardiac transplantations were performed in 19 patients. Sixteen patients had variants of hypoplastic left heart syndrome. One infant had anomalous origin of the left coronary artery with severe ischemic cardiomyopathy. Two infants had aortic stenosis with endocardial fibroelastosis, and one had extracorporeal membrane oxygenation as a bridge to transplantation. Immunosuppression included cyclosporine, azathioprine (Imuran), and corticosteroids with an effort to wean the patients from steroids by 6 months to 2 years. Three early deaths resulted--from technical errors in two patients and from hyperacute rejection in one patient at 3 days. Four late deaths have occurred. Two patients died at 2 and 13 months of acute rejection. One patient died at 15 months of acute rejection after retransplantation. One patient died at 7 months of respiratory syncytial viral pneumonia. The remaining 12 patients are surviving 5 to 47 months (means 20 months) after orthotopic cardiac transplantation. Rejection surveillance in the first 6 months is by clinical signs supplemented by echocardiography, electrocardiography, and cell cycle analysis; endomyocardial biopsy is used after 6 months of age. For the cumulative series, 24 episodes of suspected rejection have been treated during 277 at-risk patient months with intravenous methylprednisolone (Solu-Medrol) (n = 18) and monoclonal antibody (OKT3) (n = 6), for an incidence of 1.04 episodes of rejection per patient per year. Serious posttransplantation infections including endocarditis, catheter sepsis, meningitis, and colonic perforation were successfully treated in four patients. Subjectively, their quality of life is excellent as shown by normal growth and developmental milestones and a low hospital readmission rate (1.4 episodes per patient per year). These encouraging intermediate term results warrant continued application of infant orthotopic cardiac transplantation for severe forms of congenital heart disease.

Biventricular repair of hypoplastic right ventricle assisted by pulsatile bidirectional cavopulmonary anastomosis.

The right ventricle in patients with severe outflow obstruction or atresia and a small tricuspid valve often remains too hypoplastic even after optimal palliation to tolerate biventricular repair with closure of the atrial septal defect. In these patients, nonpulsatile cavopulmonary (Glenn) anastomosis has traditionally facilitated biventricular repair. In 1989, Billingsley and associates reported the addition of a bidirectional cavopulmonary anastomosis to the definitive biventricular repair in patients with hypoplastic right ventricle, pulmonary atresia, and intact ventricular septum. The atrial septal defect was left open with an adjustable snare for later closure. We report five patients with hypoplastic right ventricle (mean diastolic volume 48.4%, mean stroke volume 40.2% of predicted value) who had the atrial septal defect closed at the time of the biventricular repair. Four patients, who had the bidirectional cavopulmonary anastomosis supplementing the biventricular repair, had no evidence of excessive right atrial or superior vena cava hypertension postoperatively. One patient, who had atypical tetralogy of Fallot with tricuspid stenosis, developed recurrent pericardial tamponade and marked hepatomegaly following conventional tetralogy repair with closure of the atrial septal defect. These complications were controlled with the addition of bidirectional cavopulmonary anastomosis 2 months later. Postoperative hemodynamic or Doppler studies in these patients revealed pulsatile flow in the entire pulmonary artery system, including the artery distal to the Glenn anastomosis. This modification of biventricular repair allows primary closure of the atrial septal defect and provides pulsatile arterial flow in the entire pulmonary artery, even when the right ventricle is significantly hypoplastic.

Expanding indications for pediatric coronary artery bypass.

Pediatric coronary artery bypass has been done mostly for ischemic complications of Kawasaki disease. We reviewed our clinical experience between 1987 and 1994 with internal thoracic artery-coronary artery bypass in one infant and five children for varying indications. Indications for coronary bypass included Kawasaki disease (2), congenital left main coronary ostial stenosis, iatrogenic coronary cameral fistula, anomalous origin of the left coronary artery from the pulmonary artery, and single coronary artery traversing between the great arteries in a patient after cardiac transplantation. An additional cohort of 34 control patients of various ages and weights (1 day to 16.1 years, 2.6 kg to 62 kg) had angiographic measurements of the right coronary, left coronary, and left internal thoracic arteries with respect to the feasibility of performing coronary artery bypass. All six patients survived internal thoracic artery-left anterior descending coronary artery bypass without evidence of perioperative myocardial infarction. Postoperative angiographic studies in five and color Doppler echocardiography in one showed graft patency. Retrospective angiographic measurements in the 34 control patients showed that internal thoracic and coronary arteries are proportionately quite large in neonates and infants compared with those in older children and adolescents. Internal thoracic artery-coronary artery bypass should be considered for the expanding indications presented herein and when emergency intraoperative life-threatening situations present themselves. Long-term patency and reoperation rates have yet to be determined.

A new rat infection-heart transplant model: effect of infection on graft survival studies.

Considerable progress has been made in survival rates of heart transplant recipients; however, infections continue to be a major cause of death after transplantation. Although infection itself appears to cause immunologic suppression in some nontransplantation studies, the lack of an infection-transplant animal model has limited further investigation of this observation. We evaluated the utility of a heterotopic rat infection heart-transplant model by studying the effect of infection and limited administration of two immunosuppressive agents, cyclosporine and FK506, on allograft rejection and survival. Lewis rats received ACI heart allografts, and intraperitoneal infection was induced by cecal ligation. Infection was confirmed by blood and ascitic fluid cultures. Results showed that graft survival was slightly, but significantly, higher (p < 0.05) in group II (transplantation with infection) when compared to the control group I (transplantation only). Histologic rejection scores were less (p < 0.05) in group II 6 days after transplantation. The second phase of the study compared the effect of infection after transplantation in rats given a 1-week course of cyclosporine or FK506, which were discontinued after the induction of infection. Although the cyclosporine group had prolonged survival when compared to the FK506 group (p < 0.05), the respective infection groups receiving immunosuppression revealed no significant difference in allograft survival or histologic rejection scores when compared to the control groups. In this preliminary study, infection without immunosuppression resulted in a slight, but statistically significant, increase in allograft survival and reduced acute cellular rejection. In those groups receiving immunosuppressive agents, no additive immunosuppressive effect was attributable to bacterial infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Spectrum of humoral rejection after pediatric heart transplantation.

The deposition of immunoglobulin and complement 3 in the coronary microvasculature (humoral rejection) has been associated with poor outcome after heart transplantation. The purpose of this study is to relate the incidence of immunoglobulin and complement 3 myocardial deposition to the clinical course of pediatric heart transplant patients. One hundred thirty-one biopsy specimens from 30 patients, whose mean age at transplantation was 4.9 years (range, 2 days to 17 years), were processed for light microscopy and immunofluorescence. The mean follow-up was 25 months (range, 6 to 63 months). All patients underwent annual selective coronary artery angiography. No cellular or humoral rejection was seen in 97 biopsy specimens. Humoral rejection without cellular infiltrate was found in eight biopsy specimens from four patients (13%). Of 19 grade 1A, B (mild) biopsy specimens, 17 showed only cellular rejection, and two showed a mixed pattern of cellular and humoral rejection. Of six grade 2,3 (moderate) biopsy specimens, four showed only cellular rejection, and two showed a mixed pattern. The only grade 4 (severe) biopsy specimen revealed a mixed pattern. Three patients have had persistent immunoglobulin M and complement 3 deposits. One of these had angiographic evidence of accelerated graft coronary artery disease 2 years after transplantation, which was later confirmed at autopsy. Coronary artery disease has not been detected by serial angiography at 1 year (28 patients), 2 years (18 patients), 3 years (15 patients), 4 years (five patients), and 5 years (one patient). Humorally mediated rejection occurs with and without cellular rejection after pediatric heart transplantation. Humoral rejection may persist after treatment and resolution of severe cellular rejection episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacologic reduction of pretransplantation pulmonary vascular resistance predicts outcome after pediatric heart transplantation.

Pulmonary hypertension leading to donor right ventricular dysfunction remains a major risk factor associated with poor outcome after heart transplantation. This study evaluated a pretransplantation protocol to assess pulmonary vascular resistance index and its response to pharmacologic modulation. Cardiac catheterization was performed in 25 patients (mean age, 8.6 years [range, 1 to 17 years]; mean weight, 27.3 kg [range, 8.1 to 54 kg]) with end-stage heart failure. Mean pulmonary artery and capillary wedge pressures and cardiac index were measured in the baseline state and during administration of 100% oxygen, dobutamine at 10 micrograms/kg/min, and nitroprusside at 1 to 4 micrograms/kg/min. Transpulmonary pressure gradient and pulmonary vascular resistance index were calculated. In 22 survivors, hemodynamics were reassessed 1 and 4 weeks after transplantation. The mean cardiac index significantly increased (2.2 to 3.2 L/min/m2); transpulmonary pressure gradient (12.7 to 9.6 mm Hg) and pulmonary vascular resistance index (6.2 to 3.0 units/m2) decreased during the drug study. In 12 patients with a baseline pulmonary vascular resistance index of more than 6 units/m2, 10 survived heart transplantation. This study shows that pharmacologic reduction of the pulmonary vascular resistance index in the pretransplantation protocol predicts reduced pulmonary vascular resistance index and a favorable outcome after heart transplantation.

Influence of gender on allograft rejection in a rat heart transplant model.

BACKGROUND: Clinical studies have reported increased rejection in female heart transplant recipients. Conflicting data exist as to whether rejection is increased with male donors or female donors in these female recipients. METHODS: We investigated in this study allograft rejection in four sets of gender combinations with and without immunosuppression with the use of a heterotopic rat heart transplant model: male donor heart to female recipient, female donor heart to female recipient, male donor to male recipient, and female donor to male recipient. To examine the possible effect of androgens as an immunosuppressant, we orchiectomized a group of male recipient rats before transplantation. The rats that were not immunosuppressed were evaluated for length of graft survival (palpation). In the immunosuppressed rats (cyclosporine, 10 mg/kg x 7 days) in each gender combination half of the grafts were evaluated for length of survival (palpation) and half for cellular rejection grade at day 14 (microscopy). RESULTS: When rats that underwent transplantation were not immunosuppressed, no difference in graft survival time was found among the four sets of gender combinations. With immunosuppression, median graft survival time was 23 days in female recipients versus 32 days in male recipients (p < 0.05). Mean cellular rejection grade at day 14 was 2.95 +/- 0.7 in female recipients and 0.8 +/- 0.4 in male recipients (p < 0.01). No significant difference was found in graft survival time or cellular rejection grade with respect to donor gender. The graft survival times and cellular rejection grades of the male rats undergoing orchiectomy were not different from those of normal male recipients (p = NS). Cyclosporine levels on day 7 in both male and female recipients were high, female levels (1039 +/- 411 ng/ml) were less than male levels (2029 +/- 379 ng/ml) (p < 0.01). CONCLUSIONS: Female recipients of heterotopic rat heart transplants had shorter graft survival time and increased cellular rejection as compared with male recipients. Donor gender had no influence on graft survival or cellular rejection grade. Orchiectomy had no influence on graft survival time or grade of rejection. Results of this model suggest that female recipients may require increased immunosuppression and rejection surveillance, regardless of donor gender.

Heart transplantation in neonates and in children.

Between May 1988 and July 1991, 28 neonates and children underwent orthotopic heart transplantation at Children's Memorial Hospital in Chicago. Indications for heart transplantation were hypoplastic left heart syndrome (10), dilated cardiomyopathy (13), aortic stenosis with endocardial fibroelastosis (1), complex D-transposition of the great arteries after Senning repair (1), L-transposition of the great arteries with single ventricle after shunt (1), cor biloculare, pulmonary atresia, and situs inversus after Fontan (1), and chronic rejection after heart transplantation for hypoplastic left heart syndrome (1). The age at time of transplantation ranged from 2 days to 17 years (mean, 5.3 +/- 6.1 years). Early deaths were from intraoperative donor right ventricular failure (2) and acute rejection after a second transplant procedure at 21 days (1), for an in-hospital mortality rate of 10.7%. Immunosuppression was with cyclosporine, azathioprine, and prednisone, with an attempt to discontinue the prednisone in neonates at age 6 months as guided by endomyocardial biopsy. Rejection episodes were treated with methylprednisolone pulse (34) or with OKT3 (4). Endomyocardial biopsy (in patients older than 6 months) was used extensively, and acute rejection was diagnosed in 29 of 301 biopsies. Three late deaths occurred (mean follow-up, 16.3 +/- 11.8 months): one of acute rejection at 13 months, one of viral pneumonia at 7 months, and one of intraabdominal sepsis as a complication of peritoneal dialysis at 5 months. Actuarial survival at 2 years is 77% +/- 9% (standard error of the estimate). Heart transplantation for neonates and for children can be performed with acceptable operative mortality. Intermediate results with triple therapy immunosuppression and an intensive rejection surveillance regimen relying on endomyocardial biopsy are encouraging.

Myocardial acoustics in pediatric allograft rejection.

BACKGROUND: Ultrasonographic tissue characterization is the assessment of physical properties of biologic tissue on the basis of quantitative analysis of its acoustic characteristics. Abnormalities in microscopic structure that occur with cardiac allograft rejection may result in characteristic alterations in myocardial acoustics. Ultrasonographic tissue characterization may allow noninvasive detection of rejection. METHODS: Findings in 22 pediatric heart transplant patients undergoing routine surveillance for rejection by endomyocardial biopsy were prospectively evaluated. Off-line ultrasonographic tissue characterization analysis was done on transthoracic echocardiograms obtained at each biopsy. Within patients, tissue characterization texture measures derived from the ultrasonographic image data were compared with histologic findings. Univariate multiple regression analysis was used to identify texture measures associated with acute allograft rejection in a subgroup (n = 8) with at least one biopsy-proven episode of moderate rejection. RESULTS: Measures of homogeneity (co-occurrence matrix correlation and heterogeneity (run-length nonuniformity) decreased with moderate rejection (p < 0.03). Homogeneity measures decreased if the patient had a previous episode of rejection. Several measures of heterogeneity (gray level difference and run-length statistics) were affected by the presence of edema. Run-length nonuniformity was the only measure that differentiated moderate rejection from edema. Discriminant analysis on all 22 patients correctly identified 96% of first rejection episodes (sensitivity 80%, specificity 64%), 93% of moderate and severe rejection episodes (sensitivity 71%; specificity 62%), and 69% of all rejection episodes (sensitivity 51%, specificity 91%). CONCLUSIONS: Histologic changes associated with moderate and severe pediatric allograft rejection as reflected by characteristic alterations in myocardial acoustics can be assessed with ultrasonographic tissue characterization. Histologic changes associated with transplantation itself (resolution of rejection and edema) also affect myocardial acoustics and must be taken into account in rejection surveillance.

Cardiac transplantation for hypoplastic left heart syndrome: a modified technique [see comment].

A modified technique of infant orthotopic cardiac transplantation with arch reconstruction using bicaval cannulation is described, and the results in 4 infants with hypoplastic left heart syndrome are presented. This technique minimizes donor myocardial ischemic time and recipient circulatory arrest time.

Repair of complete atrioventricular canal defects: results with the two-patch technique.

BACKGROUND: Between 1983 and 1994, 115 infants and children underwent repair of a complete atrioventricular canal defect with the two-patch technique and routine mitral valve "cleft" closure. METHODS: A retrospective review of these 115 patients was performed. Age at the time of repair ranged from 1 month to 108 months (mean age, 14.2 +/- 16.5 months; median age, 8 months). Preoperative cardiac catheterization in 113 patients revealed a mean pulmonary to systemic flow ratio of 3.37 +/- 1.8, a mean pulmonary artery systolic pressure of 71.1 +/- 15.7 mm Hg, and a mean pulmonary vascular resistance of 4.9 +/- 3.3 units. Associated anomalies included Down's syndrome (99 patients), patent ductus arteriosus (47), and coarctation of the aorta (4). Rastelli classification was A (76 patients), B (10), C (24), and unknown (5). Twenty-four patients had intraoperative epicardial or transesophageal echocardiography. RESULTS: Although there was a trend toward increasing mean preoperative pulmonary vascular resistance with age from 2.1 +/- 0.9 units (0 to 3 months) to 4.0 +/- 2.6 units (4 to 6 months) to 5.7 +/- 3.0 units (7 to 12 months), the mean pulmonary vascular resistance of each age group was not significantly different from that of the main group. The operative survival rate was 94% (seven early deaths) and the overall survival rate, 91% (three late deaths). Intraoperative echocardiography altered the surgical therapy for 1 patient. No patient has required reoperation for a residual ventricular septal defect. Four patients (3.5%) had heart block requiring permanent pacemakers. Eight patients (7%) required reoperation for mitral insufficiency; 6 of whom had successful repair of a residual cleft. CONCLUSIONS: For infants with complete atrioventricular canal defect, repair using the two-patch technique with routine mitral valve cleft closure at 4 to 6 months of age results in a low operative mortality, a low incidence of permanent heart block, and a low reoperation rate for mitral insufficiency.

Surgical palliation of truncus arteriosus with mitral atresia and hypoplastic left ventricle.

A rare case of truncus arteriosus associated with mitral valve atresia, hypoplastic left ventricle, and intact ventricular septum is reported. Successful medical management and surgical palliation of this defect is described. The possible embryology, pertinent hemodynamics, and clinical concerns with this unusual case are discussed.

Failure of the Hemashield extension in right ventricle-to-pulmonary artery conduits.

Between 1989 and 1991, 17 children underwent 18 right ventricle-to-pulmonary artery conduit placement operations using a composite of an aortic or pulmonary valved homograft and a Hemashield extension to the ventricle. Hemashield is a collagen-coated knitted Dacron graft with excellent compliance and hemostatic properties. Diagnoses included tetralogy of Fallot with pulmonary atresia (7), truncus arteriosus (6), and complex transposition of the great arteries (4). Mean age at conduit placement was 4.9 +/- 4.2 years, and all patients survived. At a mean follow-up of 14 +/- 4 months, postoperative Doppler echocardiographic gradients between the ventricle and pulmonary artery ranged from less than 20 to 60 mm Hg. At cardiac catheterization 13 +/- 3 months postoperatively (6 patients), the systolic pressure gradient across the conduits ranged from 14 to 90 mm Hg (mean gradient, 59 +/- 29 mm Hg). Conduit obstruction, when present, was demonstrated angiographically to be in the Hemashield portion and led to early conduit replacement six times in 5 patients (33% of operations) within 10 to 18 months (mean time, 14 months) after insertion of the original conduit. Pathologic examination of the explanted conduits revealed the obstruction to be a thick neointimal peel that was impossible to separate from the Hemashield graft. Failure of the Hemashield as an extension for ventricle-to-pulmonary artery conduits secondary to accelerated neointimal formation has led us to abandon its use in clinical practice.

Inhaled nitric oxide for children with congenital heart disease and pulmonary hypertension.

BACKGROUND: Endothelium-derived nitric oxide (NO) is a potent vasodilator and a major mediator of pulmonary vascular tone. METHODS: Five infants underwent a trial of inhaled NO with hemodynamic monitoring in the operating room after atrioventricular canal repair. An additional 15 patients with congenital heart disease and refractory pulmonary hypertension were treated with inhaled NO for 1 day to 10 days postoperatively. RESULTS: In the 5 infants with atrioventricular canal, corrective surgical intervention and conventional therapy (hyperventilation, inspired oxygen fraction of 0.80, and inotropic agents) lowered mean pulmonary artery pressure from 49.5 +/- 10.5 to 20.0 +/- 2.2 mm Hg (p < 0.001). Adding inhaled NO further decreased mean pulmonary artery pressure to 18.0 +/- 2.8 mm Hg (p = not significant). Inhaled NO had no effect on ventricular function curves (inflow occlusion) in this group. In the 15 patients with refractory postoperative pulmonary hypertension, 11 had a favorable response to inhaled NO, with a decrease in mean pulmonary artery pressure from 30.9 +/- 5.8 to 23.1 +/- 5.4 mm Hg (p < 0.01) in 8 patients with pulmonary artery catheters. CONCLUSIONS: These studies demonstrate that inhaled NO has minimal beneficial effect on pulmonary artery pressure or cardiac output in infants after repair of atrioventricular canal. Inhaled NO is effective in decreasing PAP postoperatively in select patients with congenital heart disease and pulmonary hypertension refractory to conventional therapeutic modalities.