Interferon Gamma ELISPOT Testing as a Risk-Stratifying Biomarker for Kidney Transplant Injury: Results From the CTOT-01 Multicenter Study

Previous studies suggest that quantifying donor-reactive memory T cells prior to kidney transplantation by interferon gamma enzyme-linked immunosorbent spot assay (IFNγELISPOT) can assist in assessing risk of posttransplant allograft injury. Herein, we report an analysis of IFNγELISPOT results from the multicenter, Clinical Trials in Organ Transplantation-01 observational study of primary kidney transplant recipients treated with heterogeneous immunosuppression. Within the subset of 176 subjects with available IFNγELISPOT results, pretransplant IFNγELISPOT positivity surprisingly did not correlate with either the incidence of acute rejection (AR) or estimated glomerular filtration rate (eGFR) at 6- or 12-month. These unanticipated results prompted us to examine potential effect modifiers, including the use of T cell-depleting, rabbit anti-thymocyte globulin (ATG). Within the no-ATG subset, IFNγELISPOT(neg) subjects had higher 6- and 12-month eGFRs than IFNγELISPOT(pos) subjects, independent of biopsy-proven AR, peak PRA, human leukocyte antigen mismatches, African-American race, donor source, and recipient age or gender. In contrast, IFNγELISPOT status did not correlate with posttransplant eGFR in subjects given ATG. Our data confirm an association between pretransplant IFNγELISPOT positivity and lower posttransplant eGFR, but only in patients who do not receive ATG induction. Controlled studies are needed to test the hypothesis that ATG induction is preferentially beneficial to transplant candidates with high frequencies of donor-reactive memory T cells.

Multicenter validation of urinary CXCL9 as a risk-stratifying biomarker for kidney transplant injury

Noninvasive biomarkers are needed to assess immune risk and ultimately guide therapeutic decision-making following kidney transplantation. A requisite step toward these goals is validation of markers that diagnose and/or predict relevant transplant endpoints. The Clinical Trials in Organ Transplantation-01 protocol is a multicenter observational study of biomarkers in 280 adult and pediatric first kidney transplant recipients. We compared and validated urinary mRNAs and proteins as biomarkers to diagnose biopsy-proven acute rejection (AR) and stratify patients into groups based on risk for developing AR or progressive renal dysfunction. Among markers tested for diagnosing AR, urinary CXCL9 mRNA (odds ratio [OR] 2.77, positive predictive value [PPV] 61.5%, negative predictive value [NPV] 83%) and CXCL9 protein (OR 3.40, PPV 67.6%, NPV 92%) were the most robust. Low urinary CXCL9 protein in 6-month posttransplant urines obtained from stable allograft recipients classified individuals least likely to develop future AR or a decrement in estimated glomerular filtration rate between 6 and 24 months (92.5-99.3% NPV). Our results support using urinary CXCL9 for clinical decision-making following kidney transplantation. In the context of acute dysfunction, low values can rule out infectious/immunological causes of injury. Absent urinary CXCL9 at 6 months posttransplant defines a subgroup at low risk for incipient immune injury.

Arrhythmias after pediatric lung transplantation

Atrial arrhythmias have been reported after congenital heart surgery involving extensive atrial suture lines. Experimental studies involving bilateral lung transplantation (Tx) suggest that the left atrial suture lines predispose to atrial flutter. The overall incidence and type of arrhythmias after pediatric lung Tx have not previously been described and therefore the purpose of this study was to prospectively screen and describe arrhythmias in a subset of our lung transplant population. Over a 1-yr study period, all recipients of bilateral lung Tx were admitted to a full-disclosure telemetry unit. Single-lead electrocardiograms were recorded continuously and reviewed daily via a beat-by-beat analysis. A total of 314 patient days (range 9-93, median 43 days) were recorded from seven patients. The incidence of arrhythmias observed per total patient days included junctional escape rhythm (4.8%), non-sustained ventricular tachycardia (4.1%), accelerated junctional (2.5%), sinus bradycardia (2.2%), non-sustained supraventricular tachycardia (1.3%), ectopic atrial tachycardia (1.0%), sustained ventricular tachycardia (0.3%), junctional ectopic tachycardia (0.3%), and second degree heart block (0.3%). No patient had sustained supraventricular tachycardia, atrial flutter, atrial fibrillation, or complete heart block. Arrhythmias were treated in two patients. During the follow-up period, one patient received amiodarone for ventricular tachycardia (which was also noted and treated prior to transplant). We conclude that among pediatric lung transplant recipients admitted for their transplant surgery, arrhythmia is uncommon and rarely requires therapy.

Sarcoma of the mitral valve causing coronary arterial occlusion in children

Primary tumors of the cardiac valves are rare. One of the most common reasons that left-sided cardiac tumors come to clinical attention is embolization to the systemic circulation. We present two children who suffered left coronary arterial occlusion due to embolization of a sarcoma of the mitral valve. A 6-year-old female who had been admitted to the hospital after cerebrovascular embolization of a fragment of sarcoma of the mitral valve experienced sudden cardiovascular collapse due to occlusion of the left coronary artery. She was placed on extracorporeal membrane oxygenation, and underwent coronary embolectomy and resection of the tumor from the mitral valve and its tendinous cords. Left ventricular function did not improve, and she underwent orthotopic heart transplantation. On follow-up 32 months after transplant, the patient is well, with no evidence of recurrence of or metastasis from the tumor. The tumor arose from the leaflets and tendinous cords of the mitral valve, and was composed grossly of multiple white nodules. Histopathologic evaluation disclosed fragments composed predominantly of peripheral spindle cells in an extensive fibromyxoid stroma. The mildly pleomorphic cells of the tumor gradually blended with adjacent pieces of the mitral valvar leaflet and tendinous cords. Immunohistochemical studies revealed strong staining for vimentin, smooth muscle actin, muscle specific actin, and myoglobin, suggesting myogenic differentiation. The other patient was a 2 1/2-year-old female who died suddenly at home. Grossly and histologically, the tumor was essentially identical to the first case, and there was a 3 cm string-like extension passing into the orifice of the left coronary artery. To put the cases in context, we compare them with other descriptions of this rare type of tumor.

Airway growth after pediatric lung transplantation

BACKGROUND

Lung transplantation (LT) has been successfully offered to pediatric patients. Very little is known about the growth of the transplanted lung, especially in the infant population. Computerized tomography (CT) scanning is a simple method for studying pediatric patients who have undergone LT. We evaluated the use of CT scans to assess airway growth after pediatric LT, compare airway diameter indexed to somatic growth between LT patients and normals, and compare the growth of pre-anastomotic and post-anastomotic airways indexed to somatic growth in pediatric LT patients.

METHODS

We reviewed CT scans on all pediatric patients who underwent primary LT before their fifteenth birthday between January 1995 and September 1998. Uniform measurements of diameter were made in pre-anastomotic (trachea, and proximal right and left bronchi) and post-anastomotic (distal right and left bronchi) sites. These measurements were then correlated with height and compared to previously published normal values.

RESULTS

Of the 16 patients who underwent LT during the study period, 11 had at least 2 sequential CT scans (LT age 3 months to 14 years, median 2 years). Thirty-one CT scans were reviewed. Inter-observer variability was within 1 standard deviation (2 mm) in 93% of the measurements and inter-observer reliability was 0.91 by analysis of variance. Tracheal transverse diameter plotted against body height (slope 0.0072, correlation coefficient 0.88) was virtually identical to previously published norms. A similar relationship between airway diameter and height was observed in pre-anastomotic and post-anastomotic segments.

CONCLUSION

CT scanning is a reliable method for assessing airway growth in pediatric LT recipients. Tracheal growth in pediatric LT recipients is similar to that of normal children. Post-anastomotic large airways grow similarly to native, pre-anastomotic airways.

Effectiveness of pharmacomechanical thrombolysis in infants and children

Between March 1995 and February 2000, 10 children with major thromboses were treated with local pharmacomechanical thrombolysis. Clinical improvement was found in 8 patients: follow-up angiography showed complete thrombus resolution in 5 patients and subtotal resolution in 4.

Modifications to the cavopulmonary anastomosis do not eliminate early sinus node dysfunction

OBJECTIVE

To determine whether operations that theoretically jeopardize the sinus node (hemi-Fontan and/or lateral tunnel Fontan procedures) are associated with a greater risk of sinus node dysfunction than those that theoretically spare the sinus node (bidirectional Glenn and/or extracardiac conduit).

METHODS

Between January 1, 1996, and December 31, 1999, a prospective cohort study was conducted evaluating the incidence of sinus node dysfunction in patients undergoing a bidirectional Glenn or hemi-Fontan procedure and those in whom the Fontan repair was completed with either an extracardiac conduit or a lateral tunnel. Sinus node dysfunction was defined (1) as a heart rate more than 2 SD below age-adjusted norms or (2) as a predominant junctional rhythm and/or a sinus pause of more than 3 seconds as determined by the resting electrocardiogram and/or ambulatory monitoring at hospital discharge.

RESULTS

Fifty-one patients had a bidirectional Glenn shunt (mean age 7.8 +/- 5.1 months) and 79 a hemi-Fontan procedure (mean age 6.9 +/- 2.8 months). The incidence of sinus node dysfunction on postoperative day 1 was significantly higher after the hemi-Fontan (36%) than after the bidirectional Glenn shunt (9.8%); however, by hospital discharge this difference was no longer apparent (hemi-Fontan [8%]; bidirectional Glenn [6%]; P = not significant). No difference in early sinus node dysfunction was discernible after the extracardiac conduit (4/30 [13%]) compared with the lateral tunnel Fontan procedure (6/46 [13%]) (P = not significant). No diagnostic or perioperative variables were predictive of sinus node dysfunction.

CONCLUSIONS

Avoidance of surgery near the sinus node has no discernible effect on the development of early sinus node dysfunction. Thus, concerns about early sinus node dysfunction should not override patient anatomy or surgeon preference as determinants of which cavopulmonary anastomosis to perform.

Bilateral sequential lung transplant for ectodermal dysplasia

A case of bilateral sequential lung transplantation for anhidrotic ectodermal dysplasia is presented. The patient was a 16-year-old male with end-stage lung disease secondary to chronic severe respiratory infection. Although a relatively rare disease, the common association of fatal pulmonary compromise in those affected with this disorder warrants consideration of lung transplantation as a viable therapeutic option.

Survival after acute graft failure in pediatric thoracic organ transplant recipients

Survival among recipients of repeat thoracic organ transplantation, particularly in the setting of acute graft failure (AGF), is lower than survival after a primary transplant. This has created controversy over the fair allocation of scarce organs. We reviewed our experience to assess the effectiveness of aggressive therapy and retransplantation in pediatric patients with AGF. Between November 1994 and March 1998, 52 patients aged 49 days to 16.9 years (median age 4.7 years) underwent thoracic organ transplantation (32 primary and 4 repeat heart, 16 primary and 4 repeat lung, and 3 primary heart-lung transplants). Acute graft failure occurred in nine (4 heart, 3 lung, 2 heart-lung transplants), six of whom were supported with extracorporeal membrane oxygenation (ECMO), and four of whom underwent repeat transplant. Six of the nine survived, including all of those who were retransplanted, and five of the nine were alive 1 year later. The average postoperative hospital stay after receiving a second organ was 46.5 days vs. a postoperative 22-day stay in recipients without AGF (p = 0.07). We conclude that the decision to allocate institutional and professional resources to the aggressive support of patients with AGF must be made at the level of the individual transplant center. However, we feel that the outcome of aggressive support and retransplantation justifies the allocation of organs to these patients and suggests that the current policies governing organ allocation for patients with early graft failure should be re-examined.

Congenital Heart Surgery Nomenclature and Database Project: end-stage lung disease

The extant nomenclature for end-stage lung disease is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories, using synonyms where appropriate. Indications for lung transplantation are coded under a broad category called pulmonary failure. The proposed hierarchical scheme also allows classification of complications of lung transplantation under a category called status post lung transplant. A comprehensive database set is presented which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail, which can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented, which will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Prolonged extracorporeal membrane oxygenation as a bridge to cardiac transplantation

Cardiac transplantation provides the best option for neonates with congenital heart disease that is not amenable to surgical repair or palliation. The scarcity of suitable organs for this group has resulted in prolonged waiting times; many infants die awaiting transplantation. We present the case of a newborn with severe Ebstein's anomaly and low cardiac output who was supported with extracorporeal membrane oxygenation for 1,126 hours, until an appropriate organ became available.

Outcome of infants listed for lung or heart/lung transplantation

BACKGROUND

Little is known about outcome, characteristics, or organ availability for infants listed for lung or heart/lung transplantation.

METHODS

Within a 45-month period at one institution, all pediatric patients who were listed for primary lung or heart/lung transplantation and who reached the end point of either transplant or death prior to transplant were identified. Outcomes for those patients listed as younger than and older than 1 year of age were compared.

RESULTS

Among 48 pediatric patients, 19 were infants less than one year of age. The median age among infants at listing was 3.7 months (range 0.5 to 8.9 months). Death before transplant occurred in 10 of 19 infants (53%) compared with 14 of 29 (48%) children. When comparing those infants who died prior to transplant with those who received organs, there were no significant differences with respect to size, blood type, age at listing, presence of pulmonary hypertension, or type of transplant for which the patient was listed. There was a trend toward poorer pre-transplant survival for infants when compared with children. Waiting times were significantly shorter for infants vs children (p = 0.02). The incidence of acute cellular rejection and serious infection was similar in the 2 groups. Infants had significantly longer hospitalization post-transplant and a trend toward poorer hospital survival, although survival at 1 year was comparable between the 2 groups.

CONCLUSION

The outcome for infants listed for lung or heart/lung transplantation is similar to that of children; thus, very young age should not be considered a contraindication to lung or heart/lung transplantation. Earlier diagnosis and listing may decrease pre-transplant mortality.

Early survival of infants weighing 2.5 kilograms or less undergoing first-stage reconstruction for hypoplastic left heart syndrome

BACKGROUND

Results of staged palliation for hypoplastic left heart syndrome (HLHS) have improved in recent years; however, certain risk factors have been associated with decreased survival rates.

METHODS AND RESULTS

We retrospectively reviewed the medical records of 67 patients weighing </=2.5 kg undergoing the first stage of reconstructive surgery at our institution between January 1, 1990, and December 31, 1997. HLHS was present in 45 patients, complex double-outlet right ventricle in 10, unbalanced AV canal in 5, tricuspid atresia with transposition of the great vessels in 4, and other diagnoses in 3. Mean age at surgery was 10.1+/-10.7 days (median, 8 days), and mean weight was 2.2+/-0.3 kg (median, 2.2 kg). Fourteen patients weighed </=2.0 kg, and 2 patients weighed </=1.5 kg. Early mortality (death within 30 days or before hospital discharge) was 51% (34 of 67). No patient, procedural, or time-related variables correlated with increased mortality. However, there was a trend toward increased mortality with increased cardiopulmonary bypass time (P=0.076) and decreased preoperative ventricular performance (P=0.139).

CONCLUSIONS

These findings suggest that low weight alone in a patient with HLHS or an anatomic variant should not be considered a contraindication to staged reconstructive surgery.

Impact of early ventricular unloading on exercise performance in preadolescents with single ventricle Fontan physiology

OBJECTIVES

We sought to determine if early ventricular volume unloading improves aerobic capacity in patients with single ventricle Fontan physiology.

BACKGROUND

Surgical strategies for patients with single ventricle include intermediate staging or early Fontan completion to reduce the adverse affects of prolonged ventricular volume load. The impact of this strategy on exercise performance has not been evaluated.

METHODS

Retrospectively, we reviewed the exercise stress test results of all preadolescents with single ventricle Fontan physiology. "Volume unloading" was considered to have occurred at the time of bidirectional cavopulmonary anastomosis or at the time of Fontan surgery in those patients who did not undergo intermediate staging. Potential predictors of aerobic capacity were analyzed using multivariate regression.

RESULTS

The patients (n = 46) achieved a mean percentage predicted of maximal oxygen consumption (VO2max) of 76.1% +/- 21.1%. The mean age at the time of volume unloading was 2.7 +/- 2.4 years, and the mean age at testing was 8.7 +/- 2 years. Intermediate staging was performed in 16 of 46 patients (35%). In multivariate analysis, younger age at volume unloading was associated with increased aerobic capacity (p = 0.003). Other variables were not predictive. The subgroup of patients who underwent volume unloading before two years of age achieved a mean percentage predicted VO2max of 88.6% +/- 24.1%.

CONCLUSIONS

Preadolescents with single ventricle who undergo volume unloading surgery at an early age demonstrate superior aerobic capacity compared with those whose surgery is delayed until a later age.

Successful use of alternate waste nitrogen agents and hemodialysis in a patient with hyperammonemic coma after heart-lung transplantation

BACKGROUND

Lethal hyperammonemic coma has been reported in 2 adults after lung transplantation. It was associated with a massive elevation of brain glutamine levels, while plasma glutamine levels were normal or only slightly elevated. In liver tissue, glutamine synthetase activity was markedly reduced, and the histologic findings resembled those of Reye syndrome. The adequacy of therapy commonly used for inherited disorders of the urea cycle has not been adequately evaluated in patients with this form of secondary hyperammonemia.

OBJECTIVE

To determine whether hemodialysis, in conjunction with intravenous sodium phenylacetate, sodium benzoate, and arginine hydrochloride therapy, would be efficacious in a patient with hyperammonemic coma after solid-organ transplantation.

DESIGN

Case report.

SETTING

A children's hospital.

PATIENT

A 41-year-old woman with congenital heart disease developed a hyperammonemic coma with brain edema 19 days after undergoing a combined heart and lung transplantation.

METHODS

Ammonium was measured in plasma. Amino acids were quantitated in plasma and cerebrospinal fluid by column chromatography. The effectiveness of therapy was assessed by measuring plasma ammonium levels and intracranial pressure and performing sequential neurological examinations.

RESULTS

The patient had the anomalous combination of increased cerebrospinal fluid and decreased plasma glutamine levels. To our knowledge, she is the first patient with this complication after solid-organ transplantation to survive after combined therapy with sodium phenylacetate, sodium benzoate, arginine hydrochloride, and hemodialysis. Complications of the acute coma included focal motor seizures, which were controlled with carbamazepine, and difficulty with short-term memory.

CONCLUSIONS

The aggressive use of hemodialysis in conjunction with intravenous sodium phenylacetate, sodium benzoate, and arginine hydrochloride therapy may allow survival in patients after solid-organ transplantation. An acute acquired derangement in extra-central nervous system glutamine metabolism may play a role in the production of hyperammonemia in this illness that resembles Reye syndrome, and, as in other hyperammonemic disorders, the duration and degree of elevation of brain glutamine levels may be the important determining factors in responsiveness to therapy.

Heart/single-lung transplant for a "failed Fontan" with pulmonary A-V malformation

Pulmonary arteriovenous malformation can occur in patients with functional single ventricle after a cavopulmonary connection. There is no effective medical treatment for this complication. Pulmonary arteriovenous malformations may regress over time after heart transplantation, but may be a source of significant perioperative morbidity. We report the case of a woman with single ventricle, ventricular dysfunction, and bilateral pulmonary arteriovenous malformations who had successful treatment of both cardiac and pulmonary failure with en bloc heart and right lung transplantation.

Adenovirus infection in the lung results in graft failure after lung transplantation

OBJECTIVES

Our goal was to examine the relationship between viral pneumonia and outcome in pediatric patients undergoing lung or heart-lung transplantation.

METHODS

Prospective surveillance for common respiratory viruses of childhood was performed in all patients undergoing lung or heart-lung transplantation. Specimens were examined for the presence of replicating virus (by culture), viral genome (by polymerase chain reaction), and viral antigen (by immunofluorescence and immunohistochemical staining). The relationship between viral infection and outcome was examined.

RESULTS

Sixteen patients underwent 19 transplants during the study period, with follow-up of 1 to 26 months. Virus was identified in the transplanted lung in 29 instances; adenovirus was identified most commonly (8/16 patients) and had the greatest impact on outcome. In 2 patients with early, fulminant infection, adenovirus was also identified in the donor. Adenovirus was significantly associated with respiratory failure leading to death or graft loss and with the histologic diagnosis of obliterative bronchiolitis (P < or = .002 in each case).

CONCLUSIONS

Adenovirus infection in the transplanted lung is significantly associated with graft failure, histologic obliterative bronchiolitis, and death. Health care personnel and families must be vigilant in preventing exposure of transplant recipients to this virus. Availability of a rapid and reliable test for adenovirus in donors and recipients would have an impact on management and could improve outcome for pediatric lung recipients.

Update on lung transplantation in children

Lung transplantation is an important treatment option in children with acquired and congenital pulmonary disease. Indications for lung transplantation include pulmonary hypertension, bronchopulmonary dysplasia, pulmonary vein stenosis, and cystic fibrosis. The early outcome following lung transplantation has improved considerably. Longterm complications, however, including infections, bronchiolitis obliterans, and complications of immunosuppression remain significant problems. Donor availability, especially for neonates, continues to limit the utilization of lung transplantation.

Lung transplantation in children

Fewer than 50 pediatric lung transplants are performed each year. Surgical advances in the field have resulted in improved operative outcomes and in technical innovations that have broadened both the target population and the donor pool. At the same time, late referral of critically ill patients and shortage of donor organs result in death prior to transplantation for many children, and substantial biological barriers exist that prevent achievement of satisfactory long-term outcomes for the many who do undergo a successful surgical procedure. Until we can better understand and overcome these barriers, lung transplantation must be considered a palliative rather than curative procedure. In this article, a brief overview of pediatric lung transplantation is offered, and contributions to the recent literature are summarized.

Hemodynamic data and survival in children with pulmonary hypertension

OBJECTIVES

Using data from a multi-institutional data base, we sought to determine whether hemodynamic data predict duration of survival in children with primary or secondary pulmonary hypertension.

BACKGROUND

Lung transplantation is a therapeutic option for children with pulmonary hypertension. Appropriate timing of lung transplantation requires reliable methods of predicting duration of survival in potential candidates.

METHODS

A regional data base was used to obtain cardiac catheterization data on 50 children with mean pulmonary artery pressure (mPAP) > 25 mm Hg and indexed pulmonary resistance (Rp) > 4.5 Wood units. Data on survival were obtained from the participating centers.

RESULTS

There were 15 patients without congenital heart disease (group 1) and 35 patients with congenital heart disease (group 2) for analysis. Actuarial survival at 1, 2 and 5 years was 86%, 69% and 69% in group 1 and 88% and 77% in group 2, respectively (p = NS). Hemodynamic variables that predicted survival on univariate analysis were mean right atrial pressure (mRAP) (p < 0.0001), mPAP (p = 0.034), Rp (p < 0.0001) and pulmonary flow (p = 0.003), as well as a variable that we generated-mRAP x Rp (p < 0.0001). On multivariate stepwise logistic regression analysis, mRAP x Rp was independently related to survival. A model using mRAP x Rp allows for the estimation of probability of death at 1 and 2 years after catheterization.

CONCLUSIONS

Hemodynamic variables can predict survival in children with pulmonary hypertension in the presence or absence of congenital heart defects. This information can be used to determine the optimal timing of listing for lung transplantation.

Pediatric lung transplantation at St. Louis Children's Hospital, 1990-1995

Although accepted therapy in adults, lung transplantation in children is less well established. Reports from the few existing pediatric centers have involved relatively small patient number. Seventy-nine patients underwent 88 lung transplant procedures at St. Louis Children's Hospital between June 1990 and August 1995. Twenty-one transplants (24%) were done in 19 infants and children under the age of 3 yr. Twelve-, 24-, and 48-mo actuarial survival for the primary transplants was 69%, 67%, and 60%, respectively. Survival improved over the course of the program: 12-mo survival for patients transplanted during the first 18 mo was 42% compared with 78% for those transplanted after December 1991. Survival of children transplanted at younger than 3 yr of age was comparable to older children and adults. However, younger children had a lower incidence of acute rejection; none developed bronchiolitis obliterans. Both graft growth and linear growth occurred. Risk factors for early mortality included presence of aortopulmonary collateral vessels and prior thoracic surgery. Risk factors for survival duration included requiring assisted ventilation at the time of transplant, continuous supplemental oxygen requirement, and presence of aortopulmonary collateral vessels. The major late complication was bronchiolitis obliterans, which occurred in 27% of patients and played a role in 64% of late deaths. Investigation of the lower incidence of acute rejection and bronchiolitis obliterans in younger versus older children may reveal important information about the etiology of this disease. The ultimate long-term success of lung transplantation will depend on identification and treatment of the mechanisms responsible. A multicenter data registry would facilitate further clinical studies of pediatric lung transplantation.

Pediatric lung transplantation--are there surgical contraindications?

Lung transplantation has evolved as a successful treatment for end-stage cardiopulmonary disease in children; however, clear guidelines regarding surgical exclusion criteria for pediatric lung transplant candidates have not been well-established. Since December 1994, we have performed 10 bilateral lung transplants and 1 heart-lung transplant in 10 recipients (mean age, 7 years; range, 3 months to 19 years). Indications for transplantation included pulmonary vascular disease (n=6), bronchiolitis obliterans (n=2), bronchopulmonary dysplasia (n=1), graft failure due to viral pneumonitis (n=1), and cystic fibrosis (n=1). Among the 10 patients, 4 were evaluated elsewhere for lung transplantation; of these, 3 were rejected by 1 or more programs because of "high-risk" characteristics. We considered 8 of the 10 patients to have 1 or more "high-risk" characteristics, as follows: previous chest operations other than open lung biopsy (n=6 patients having 1-4 previous operations), ventilator-dependence with tracheostomy and high-dose corticosteroids (n=4), redo lung transplant (n=2), concomitant intracardiac repair (n=6), portal hypertension (n=1), and the use of extracorporeal membrane oxygenation (ECMO) at the time of transplant (n=1). Our standard operative approach was a bilateral thoracosternotomy. Cardiopulmonary bypass was used for explant of the recipient lungs and implant of the donor lungs, and during repair of coexisting congenital heart defects. Aprotinin and fresh whole blood were administered during the procedure to aid in hemostasis. Concomitant procedures were frequently performed and included repair of an intra-atrial baffle leak (prior Mustard procedure), closure of an atrial septal defect, repair of partial anomalous pulmonary venous return, reconstruction of the pulmonary venous confluence, ECMO decannulation, and splenectomy. There were no operative deaths, and no patient required re-exploration for bleeding. One patient had primary graft failure due to adenovirus infection of the donor lungs, and required prolonged mechanical ventilation and eventually ECMO support until retransplantation was performed. The mean hospital stay after transplant was 25+/-13 days (range, 10-56 days). All patients were discharged with a natural airway. Airway complications consisted of one bronchial anastomotic stricture which required dilation, for a complication rate of 5% per anastomoses at risk. One patient required reoperation for stenosis of the superior vena cava. There have been no late deaths, with a mean follow-up of 7+/-4 months (range, 1-13 months). We attribute this 100% operative and short-term survival in these "high-risk" pediatric lung transplant recipients to our operative methods, a multidisciplinary approach to postoperative management, and the enormous physiologic reserve of pediatric patients. Therefore, the standard exclusion criteria used for adult lung transplantation may not be applicable to the pediatric age group. We hope to use these data to expand the use of lung transplantation in pediatric patients.

Outcome of children with pulmonary hypertension referred for lung or heart and lung transplantation

We reviewed our institutional experience with 24 children with pulmonary hypertension, who were referred for lung or heart and lung transplantation. Diagnosis, age, and previously published predictive survival scores calculated at the time of referral were analyzed as predictors of pretransplant death. Among the 24 children, 7 did not meet criteria for listing and 17 were listed for transplantation. Of those listed, eight died waiting, two await transplantation, and seven were transplanted and are alive and well 7-20 months after transplantation. Poor functional status (New York Heart Association class 3 or 4) at the time of referral was significantly associated with death before transplant (P=0.05) in univariate analysis. Analysis of the predictive scores was possible in 21 of 24 patients; lower predictive scores were significantly associated with death before transplantation and shorter duration of survival without transplantation in univariate analysis. Multivariate analysis (Cox regression) confirmed that lower scores were significantly associated with poor survival. We conclude that children with pulmonary hypertension are often referred for transplantation too late in the course of their disease. Early complete hemodynamic evaluation before the onset of severe symptoms, followed by serial evaluations of disease progression and consultation with a transplant center, should result in earlier, more appropriate time of listing and improved survival. A systematic study of pretransplant mortality among all children listed for lung transplantation would provide a basis for clinical decision making and policies affecting organ allocation.

Lung transplantation in infancy and early childhood

BACKGROUND

Experience with lung transplantation in infants and young children is limited. Small size, vulnerability to infection, and limited modalities for rehabilitation and surveillance of the transplanted lung make this group particularly challenging.

METHODS

We reviewed the course of all children up to the age of 25 months who underwent lung transplantation at two centers between July 1990 and February 1995.

RESULTS

Lung transplantation was performed in 17 patients under the age of 25 months, with concurrent cardiac repair in 14. Prior thoracic surgery had been performed in 12; six patients had mechanical ventilation, and three were supported with extracorporeal membrane oxygenation while waiting for lungs. The mean waiting time was 37 days (range 1 to 197 days). Hospital survival was 12 of 17 (71%); there was one late death. Early deaths were due to hemorrhage (two patients), cytomegalovirus and lymphoproliferative disease (one patients), and viral pneumonitis (two patients). The one late death was due to overwhelming gastroenteritis of unknown origin. One additional patient had graft failure caused by viral pneumonitis and underwent successful retransplantation. Bronchial stenosis occurred at 3 of 33 anastomoses. At a mean follow-up of 22 months, surviving patients were well, without supplemental oxygen, and, although small in stature, had normal linear growth.

CONCLUSIONS

Lung transplantation is a reasonable therapy for very young patients with limited life expectancy and no other therapeutic alternative, with outcomes comparable with those achieved in older patients. Early recognition of lung transplant candidates and advances in the prevention, diagnosis, and treatment of viral illness may improve survival in these patients.

Lung transplantation in children

Lung transplantation can offer improved quality of life and prolonged survival to children who have end-stage cardiopulmonary disease, even in the presence of characteristics that have been considered poor prognostic indicators. At present, children who have pulmonary hypertension tend to be referred for transplantation late in the course of their disease; as a result, almost half die before organs become available. Cardiac catheterization for accurate disease staging, appropriate timing of evaluation and listing for transplantation, and referral to centers experienced in the treatment of children who have end-stage cardiovascular disease are all essential components of a process that will improve survival in such children. Our experience indicates that there may be important developmental differences in the body's response to lung transplantation; thus, protocols that are suitable for older adolescents and adults may be unsuitable for young children. An integrative approach to investigation of these issues, i.e., one in which careful clinical observation and data acquisition are combined with targeted bench research, is most likely to result in insights that will directly benefit patients.

Echocardiographic characteristics of biopsy-proven cellular rejection in infant heart transplant recipients

BACKGROUND

Echocardiography has been used as a primary means to detect cellular rejection in infant heart transplant recipients. There is, however, limited information correlating echocardiography and biopsy-proven rejection in this age group.

METHODS

Between September 1989 and July 1994, 32 consecutive heart transplantations were done in infants younger than 20 months old, who were followed up for 2 to 58 months (mean 28 months) with concurrent endomyocardial biopsy and M-mode echocardiography with digitization. M-mode data from all 16 episodes of rejection (International Society for Heart and Lung Transplantation grade 3A or greater) that occurred in 12 grafts were compared with data from the same grafts with histologic resolution of rejection 2 weeks after treatment and with data from biopsy-proven nonrejecting control grafts matched for sex, time after transplantation, donor weight, and donor age.

RESULTS

Left ventricular mass index increased in rejection (86 +/- 9 gm/m2) versus resolution (64 +/- 6 gm/m2) and versus that in nonrejecting control grafts (59 +/- 8 gm/m2). Left ventricular shortening fraction increased in rejection (40% +/- 2%) versus resolution (38% +/- 10%). Septal thickening fraction decreased in rejection (33% +/- 9%) versus nonrejection (68% +/- 16%). These changes became significant only in grafts transplanted more than 1 month before study. Substantial overlap of measurements prevented identification of threshold values. Intraobserver and interobserver variabilities for standard M-mode data were 7% to 8% and 12% to 22%, respectively, whereas those for digitized parameters were markedly elevated at 37% to 71% and 51% to 81%, respectively.

CONCLUSIONS

We found (1) left ventricular mass index increases in cellular rejection but may be unreliable less than 1 month after transplantation and (2) significant interobserver and intraobserver variability may limit the applicability of digitized echo parameters to the detection of rejection in infant heart transplant recipients.

Orthodeoxia-platypnea due to intracardiac shunting--relief with transcatheter double umbrella closure

The safety and efficacy of transcatheter clamshell occlusion of patent foramen ovale for relief of severe arterial desaturation and dyspnea in the upright position due to intracardiac shunting were examined in eight patients with excessive risk of surgical patent foramen ovale closure. All patients had successful reduction of intracardiac shunting with an immediate rise in oxygen saturation > or = 95% by implantation of a clamshell device on the atrial septum. Despite two early incidents of device embolization, retrieval and immediate re-implantation, and one patient with nonsustained atrial and ventricular arrhythmias, there were no adverse clinical sequelae. In follow-up evaluation transcatheter clamshell closure of patent foramen ovale has provided persistent relief from shunt-related arterial desaturation and symptomatology in all living patients.

Lung transplantation for congenital pulmonary vein stenosis

BACKGROUND

Congenital pulmonary vein stenosis is a uniformly fatal disease when left untreated. Transcatheter techniques (for example, balloon dilation and stent placement) have proved to be only temporizing measures, and previous surgical attempts at treatment of this entity have provided little improvement and few survivors.

METHODS

Over the last 4 years, 6 patients with congenital pulmonary vein stenosis have been treated at our institution, 3 of whom underwent bilateral sequential lung transplantation.

RESULTS

The 3 patients who underwent bilateral lung transplantation are alive and well 6 to 24 months after transplantation. The other 3 died of complications of the disease before donor lungs became available.

CONCLUSIONS

Making the diagnosis of congenital pulmonary vein stenosis requires a high index of suspicion, and referral for lung transplantation should be made as soon as the diagnosis is reached. Lung transplantation has resulted in good-quality short to medium-term survival for 3 patients with this otherwise untreatable disease.

Cardiac catheterization and test occlusion of the interatrial communication after the fenestrated Fontan operation

OBJECTIVES

Our objective was to determine whether catheterization data obtained after a fenestrated Fontan operation influenced patient management or predicted functional status.

BACKGROUND

Cardiac catheterization after a fenestrated Fontan operation is undertaken to identify residual lesions and to observe the patient's response to test occlusion of the baffle fenestration.

METHODS

Sixty patients undergoing both a fenestrated Fontan operation before July 1991 and a postoperative catheterization before March 1992 were included in the study. Catheterization data were collected according to a test occlusion protocol; these data were reviewed, and the patient's clinical status at follow-up was ascertained.

RESULTS

Test occlusion resulted in a significant increase in systemic venous pressure, arterial oxygen saturation and arteriovenous difference in oxygen content (p < 0.0001). After test occlusion, systemic venous pressure was 40% higher and systemic venous saturation 23% lower among patients with an unfavorable versus a favorable response to test occlusion, although differences between the two groups were subtle or inapparent in the baseline state. Branch pulmonary artery stenosis (identified and balloon dilated in 6 patients) and grade 2 or 3 aortopulmonary collateral vessels (identified and coil embolized in 20) were associated with elevation in systemic venous pressure (p < 0.01). After an average of 2 years of follow-up, there were no deaths, and 50 (83%) of 60 patients were in New York Heart Association functional class I. The only postoperative characteristic significantly associated with being in functional class I at follow-up was a systemic venous pressure < 17 mm Hg.

CONCLUSIONS

Cardiac catheterization with test occlusion of the interatrial communication provides useful information after a fenestrated Fontan operation. Conditions associated with elevated systemic venous pressure should be sought and treated, and the response of systemic venous pressure to test occlusion should be considered when deciding whether to close an interatrial communication.

Lung transplantation in children and young adults with cardiovascular disease

Single or bilateral lung transplantation was performed in 20 patients with pulmonary hypertension or an inadequate pulmonary vascular bed; all but 1 had congenital heart disease. The average age was 6.3 years (range, 3 months to 23.9 years). All were in New York Heart Association class IV, and 6 were hospitalized and receiving intensive support before transplantation. Hospital survival was 70% (14/20), with three additional deaths at 7, 11, and 27 months. A prior thoracic operation contributed to three of six hospital deaths from hemorrhage. All late deaths were due directly or indirectly to obliterative bronchiolitis. At a mean follow-up of 19 months (range, 2 to 48 months), 10 of 11 survivors are in New York Heart Association class I. Survival after hospital discharge and incidence of obliterative bronchiolitis are similar in a contemporary group of 41 patients of comparable age who underwent lung transplantation for pulmonary disease (p = not significant). Single or bilateral lung transplantation is an acceptable therapy for children with pulmonary hypertension, congenital heart disease, or both. Further investigation in the areas of pretransplantation survival, operative risk factors, and long-term outcome of single-lung recipients and recipients with hemodynamically insignificant intracardiac lesions are needed to develop optimal decision-making strategies for these patients.

Rational approach to use of heparin during cardiac catheterization in children

OBJECTIVES

We sought to determine an anticoagulation protocol for use during cardiac catheterization in children.

BACKGROUND

There are few data to indicate which dose of heparin represents adequate anticoagulation or how best to monitor its efficacy. In this study, adequate anticoagulation was defined as the amount of heparin needed to prevent a significant increase in serum fibrinopeptide A, a sensitive marker for thrombin activity. The degree of heparinization was estimated by the activated clotting time.

METHODS

Thirty-six children (1 month to 19.5 years old) with congenital heart disease underwent diagnostic cardiac catheterization; 13 of these 36 patients had an additional interventional procedure. Sheaths and catheters were flushed with heparinized saline (1 IU/ml); during the procedure, 33 of the 36 patients received either a 50- or a 100-IU/kg heparin bolus. Paired fibrinopeptide A and activated clotting time samples were obtained throughout each procedure.

RESULTS

Increasing the activated clotting time with heparin resulted in a dose-related decrease in fibrinopeptide A levels. A single heparin bolus of either 50 or 100 IU/kg elevated the activated clotting time above baseline level (209 +/- 52 s after 50 IU/kg, 270 +/- 57 s after 100 IU/kg vs. 133 +/- 20 s at baseline [p < 0.0001]) and reduced fibrinopeptide A levels below baseline (7.9 +/- 14 ng/ml after 50 IU/kg, 4.8 +/- 3.7 ng/ml after 100 IU/kg vs. 38 +/- 59 ng/ml at baseline [p < 0.0001]). Heparin flush alone did not increase the activated clotting time above baseline and failed to suppress an increase in fibrinopeptide A levels. There were no differences in activated clotting time and fibrinopeptide A values between patients undergoing diagnostic or interventional procedures.

CONCLUSIONS

Administration of a heparin bolus to maintain an activated clotting time > 200 s prevented a significant increase in thrombin activity. Heparin flush alone did not provide adequate anticoagulation. Patients undergoing an interventional procedure did not require more heparin than that needed for a diagnostic procedure.

Maturational and hemodynamic factors predictive of increased cyanosis after bidirectional cavopulmonary anastomosis

Bidirectional cavopulmonary anastomosis (BCA) is thought to be beneficial in the palliation of patients with univentricular congenital heart disease considered at high risk for Fontan repair. Experience with patients undergoing BCA suggested that those who were older or larger at the time of surgery tended to be more cyanotic postoperatively than their younger and smaller counterparts. This study was designed to identify correlates of systemic arterial oxygen saturation after BCA. Specifically, it was postulated that maturational changes in blood flow distribution might be associated with decreasing arterial oxygen saturation. Database records of all 110 patients undergoing BCA at our institution from June 1988 until the end of 1991 were reviewed. Postoperative catheterization data were available for 66 patients. Twenty-one patients were excluded because they had potentially reversible causes of cyanosis yielding inestimable degrees of error in hemodynamic calculations. In the remaining 45 patients, univariate and multivariate regression analyses were used to identify correlates of systemic arterial oxygen saturation. Growth and maturation as represented by body surface area exhibited a highly significant inverse correlation with arterial oxygen saturation (p = 0.005), as did pulmonary vascular resistance (p = 0.003). Patients who underwent BCA when > 3.9 years of age or with body surface area > 0.65 m2 were at significantly increased risk for excessive postoperative cyanosis, defined as systemic arterial oxygen saturation < or = 75% (p < 0.005). The interval between surgery and catheterization correlated directly with arterial oxygen saturation (p = 0.002), indicating a tendency toward earlier study of more cyanotic patients. None of the other variables examined correlated significantly with arterial oxygen saturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of operative mortality and morbidity after infant heart transplantation

We retrospectively analyzed the impact of recipient, donor, and operative factors on the operative mortality and morbidity of 36 consecutive infant heart transplantations. Operative survival was excellent at 94%. Among 34 survivors, operative morbidity in 12 patients included acute severe allograft failure with or without prolonged ventilatory support. The cohort was characterized by age less than 4 months (32 of 36), a diagnosis of hypoplastic left heart syndrome (29 of 36), and the use of circulatory arrest (27 of 36); these variables were colinear and could not be used to predict operative mortality or morbidity. None of the remaining recipient, donor, or operative characteristics predicted survival or acute severe allograft failure. A donor-to-recipient weight ratio greater than 2 and a circulatory arrest time greater than 39 minutes predicted the need for prolonged ventilatory support. Despite the need for aggressive or prolonged support after 12 of 36 transplantations, operative survival was high at 94% (34 of 36 procedures, 32 of 34 patients). The use of less restrictive donor criteria combined with aggressive management of acute allograft failure can result in excellent operative survival after infant heart transplantation.

Transcatheter coil embolisation of a pulmonary arteriovenous malformation in a neonate

Pulmonary arteriovenous malformations (PAVM) are a rare cause of cyanosis in neonates. A large PAVM in a neonate was successfully occluded by transcatheter embolisation. At six months follow up the PAVM was undetectable and no new lesions were found. Transcatheter embolisation should be considered as the primary treatment for a PAVM in a child of any age.

Intraoperative device closure of ventricular septal defects

BACKGROUND

Surgical repair of muscular ventricular septal defects (VSDs) has been associated with significant morbidity and mortality when the defects are multiple, associated with complex cardiac lesions, or requiring left ventriculotomy. Transcatheter VSD closure may be difficult in patients weighing less than 7 kg or those with limited vascular access. We attempted intraoperative device closure of muscular VSDs during surgical repair of associated lesions.

METHODS AND RESULTS

We considered intraoperative umbrella closure in 10 patients, 8 with additional complex heart lesions. "Swiss cheese" defects were present in 4. Median patient age was 4.7 months. Device closure was not attempted in 1 patient due to an inadequate septal rim. Nine umbrellas, 12 to 40 mm in diameter, were positioned to straddle the septum in all 9 patients. There were 3 early deaths, 2 in patients who were moribund preoperatively. The third was due to severe ventricular dysfunction. Among the 6 survivors, 3 had a Qp:Qs < or = 2 and right ventricular or pulmonary artery pressure less than half systemic. These patients had no further intervention. The other 3 had a Qp:Qs > 2. One died unexpectedly 5 weeks after cardiac surgery. The other 2 had subsequent closure of residual VSDs. All 5 survivors are well at follow-up of 8 to 25 months.

CONCLUSIONS

Intraoperative umbrella VSD closure appears less successful than VSD closure in the catheterization laboratory. In selected patients, particularly very small infants, intraoperative device placement may be advantageous. Completeness of closure is difficult to assess intraoperatively.

Prevalence and risk factors for aortopulmonary collateral vessels after Fontan and bidirectional Glenn procedures

OBJECTIVES

The purpose of this study was to evaluate the prevalence of and risk factors for aortopulmonary collateral vessels in patients who have undergone a bidirectional Glenn or Fontan procedure, or both.

BACKGROUND

Aortopulmonary collateral vessels are frequently observed angiographically in patients after a bidirectional Glenn or Fontan procedure. These vessels may provide a source of pulmonary blood flow competitive with anterograde cavopulmonary flow.

METHODS

We performed a retrospective study of all patients (n = 196) who underwent catheterization between January 1, 1988 and February 29, 1992 (n = 268) after bidirectional Glenn or Fontan procedures and reviewed clinical, hemodynamic and angiographic phone data.

RESULTS

Collateral vessels were diagnosed in 36% of patients. Patients who underwent the bidirectional Glenn procedure were more likely to have collateral vessels than patients who underwent the Fontan procedure (65% vs. 30%, respectively; p < 0.0001). Patients with a history of a Blalock-Taussig shunt were more likely to have collateral vessels than those without (50% vs. 24%, respectively; p = 0.0006). Discretely identifiable collateral vessels were measurable in 54 (20%) of 268 catheterizations. The total estimated cross-sectional area of these vessels averaged 10.7 +/- 7.2 mm2. In patients who underwent the bidirectional Glenn procedure, a step-up in oxygen saturation from the superior vena cava to the distal pulmonary arteries or an upper lobe filling defect, or both, on pulmonary angiogram predicted total estimated cross-sectional area of collateral vessels. Most collateral vessels originated from the internal mammary arteries (34%) and the thyrocervical trunks (22%). Only 9% of collateral vessels arising from the brachiocephalic vessels were visualized by aortogram; the remainder required selective angiography in the subclavian or more distal arteries.

CONCLUSIONS

Aortopulmonary collateral vessels are common after bidirectional Glenn and Fontan procedures. Aortograms often fail to diagnose their presence. The left to right shunt carried by these vessels is associated with a step-up in oxygen saturation in the distal pulmonary arteries. The clinical significance and indications for closure of these vessels are not known.

Transcatheter closure of atrial and ventricular septal defects

The clamshell double umbrella (Bard Clamshell Septal Umbrella, USCI Division, C. R. Bard, Billerica, MA) was developed to allow closure of septal defects, both atrial and ventricular. The device and delivery system and the techniques for implanting the device in atrial and ventricular defects are described in detail. Although fractures of the arms supporting the umbrellas in some patients have lead to modification of the device, the early experience in clinical trails are encouraging.

Enlarged bronchial arteries after early repair of transposition of the great arteries

OBJECTIVES

This study was undertaken to define the incidence of enlarged bronchial arteries after early surgical repair of transposition of the great arteries by the arterial switch operation, and to report the results of catheter-directed therapy in five patients.

BACKGROUND

Pathologic and angiographic studies have demonstrated enlarged bronchial arteries in patients with transposition of the great arteries.

METHODS

A subjective 4-point scale was used to grade postoperative angiograms performed in 119 patients at our institution between January 1983 and December 1991. Grades 0 and 1 were designated if there was no opacification of the pulmonary arteries or veins, whereas grades 2 and 3 were assigned if there was such opacification. The median age at repair was 8 days (range 1 day to 13 months) and the median age at catheterization was 11.2 months (range 3.6 to 58.5). An intact ventricular septum was present in 84 (71%) of 119 patients.

RESULTS

Significantly increased bronchial flow (grade 2 or 3) was present in 55 (46%) of 119 patients. Age at repair, age at catheterization and interval between repair and catheterization were not associated with significantly increased bronchial flow; however, an intact ventricular septum was weakly associated with increased flow (p = 0.04). Coil embolization was performed in five patients with complete occlusion of the vessels and no significant complications.

CONCLUSIONS

Abnormally enlarged bronchial arteries are frequently identified at postoperative catheterization despite early repair and may explain continuous murmurs or persistent cardiomegaly in patients with otherwise normal noninvasive findings. When clinically indicated, catheter-directed therapy can be performed with good results.

Devices for transcatheter closure of intracardiac defects

Transcatheter closure of intracardiac defects is an investigational procedure that is in use at a number of centers in North America and Europe. A radiologist should be able to recognize these devices on a chest radiograph, understand their actual physical appearance, and be able to recognize their expected location. This essay summarizes the indications for, technical aspects of, and radiologic appearance of these devices.

Effect of baffle fenestration on outcome of the modified Fontan operation

BACKGROUND

The "fenestrated Fontan" (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome.

METHODS AND RESULTS

Patients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n = 91) were compared with those without baffle fenestration (n = 56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p < 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration, p = NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p < 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p < 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I).

CONCLUSIONS

Baffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation.

Transcatheter closure of patent foramen ovale after presumed paradoxical embolism

BACKGROUND

Many have proposed a relation between presence of a patent foramen ovale, with or without atrial septal aneurysm, and cryptogenic stroke. The effect of foramen ovale closure on the risk for subsequent strokes is unknown.

METHODS AND RESULTS

Transcatheter closure of a patent foramen ovale was undertaken in 36 patients with known right-to-left atrial shunting and presumed paradoxical emboli (31 strokes, 25 transient neurological events, four systemic arterial emboli, and two brain abscesses). Individual patients had between one and four such events. None had a left heart or carotid source of embolism; 31 of 35 had no known risk factors for stroke. Events occurred in 12 patients while they were taking warfarin. At cardiac catheterization, patent foramina ovalia were significantly larger than predicted for age in 67% of the patients. Implantation of a double-umbrella device in the patent foramen ovale was achieved in all without serious procedural complications. Of 34 who have returned for follow-up, one has a residual atrial communication that may be clinically important, five had trivial leaks, and 28 have complete closure. There have been no strokes during a mean follow-up of 8.4 months.

CONCLUSIONS

Transcatheter closure of a patent foramen ovale can be accomplished with little morbidity and may reduce the risk of recurrence. Further investigations directed toward identifying the population at risk and assessing the effect of intervention are warranted.

The fenestrated Fontan procedure

In 90 patients with characteristics placing them at increased risk for a Fontan operation, a fenestration was created in the atrial baffle at the time of the Fontan repair. The rational was to allow a right to left shunt which would maintain cardiac output and limit right atrial pressure in the presence of conditions which limit pulmonary blood flow. Early mortality was 4/90 (4%), with an additional two patients having the Fontan repair taken down to a bidirectional cavopulmonary anastomosis. Postoperative right atrial pressures were low (average 13 mm Hg), as was the incidence of prolonged pleural effusions (13%). At short-term (average 13 months) follow-up, 77% of patients have had closure of the fenestration, and 92% are in New York Heart Association Class I. We conclude that baffle fenestration with subsequent transcatheter closure results in decreased mortality and morbidity among high risk patients undergoing a Fontan repair, and that the high functional level at short-term follow-up justifies continued aggressive management of such patients.

Factors associated with marked reduction in mortality for Fontan operations in patients with single ventricle

The Fontan operation was originally employed for patients with tricuspid atresia, but its application has been extended to those with a variety of complex defects in which there is functionally only a single ventricular chamber. The outcome of 225 modified Fontan operations carried out between 1984 and 1990 at the Children's Hospital, Boston, for patients with defects other than tricuspid atresia was reviewed. Overall 30 patients (13.3%) had failure of this operation (death or takedown). Results improved significantly during the period of the study, with failure rates of 6.5% (2 of 31) and 3.4% (2 of 59) in the last 2 years of the review. Multivariate analysis showed that pulmonary artery distortion, pulmonary artery pressure, age less than 3 years, use of a nonoxygenated glucose K+ cardioplegic solution, and cardiopulmonary bypass time greater than 180 minutes were associated with worse outcome, while "favorable" atrioventricular valve anatomy (non-left atrioventricular valve stenosis/atresia or common atrioventricular valve) and age greater than 9 years were associated with improved outcome. Excluding cardiopulmonary bypass time from the multivariate analysis, the technique of atrial partitioning for patients with left atrioventricular valve atresia/stenosis became the most important variable, followed by the others noted in the initial multivariate analysis except for age greater than 9 years. In the last 2 years of the study 31.1% of patients were less than 3 years of age. During the period of the study there was no significant decline in preoperative risk factors. These results show that modified Fontan operations can be carried out with a high likelihood of success in properly selected patients with complex defects in whom there is functionally a single ventricle.

Transcatheter closure of atrial septal defects: hemodynamic complications and anesthetic management

Transcatheter closure of atrial septal defects using a double-umbrella (clamshell) device can now be performed during an overnight hospital stay with little morbidity and no mortality. The initial 2-yr experience with anesthetic care for the procedure was collected and subsequently analyzed. Primary anesthetic care was given in 118 cases and urgent anesthetic intervention was required in another four cases. Anesthesia with spontaneous ventilation in patients with unprotected airways using intravenous ketamine and midazolam (average cumulative doses 1.4 and 0.17 mg.kg-1.h-1, respectively) was used in 93 cases (77%); mean maximum PaCO2 value was 41 +/- 6 mm Hg. In 29 patients (23%) tracheal intubation and muscle paralysis were used to facilitate control of airway and ventilation. Anesthetic-related complications occurred in three patients: ventilatory compromise developed in two patients in the spontaneous ventilation group and one patient experienced awareness during endotracheal anesthesia with paralysis. Procedural complications that altered anesthetic management were more frequent, including embolization of the clamshell device requiring surgical retrieval in two of six embolizations, intracardiac air embolization (four cases), tricuspid regurgitation (one case), device malplacement requiring late operation (one case), and transient brachial plexus injury (three cases). Anesthesia for transcatheter atrial septal defect closure allows precise device placement, prompt control of hemodynamic complications, and transesophageal echocardiographic monitoring of device placement. Although general anesthesia with spontaneous ventilation using ketamine and midazolam was usually safe and effective, tracheal intubation for control of airway and ventilation was sometimes necessary for safety and for optimal operating conditions. Familiarity with transcatheter closure techniques and close communication with the catheterization team is essential to minimize and treat associated complications.(ABSTRACT TRUNCATED AT 250 WORDS)