Cardiac transplantation in infants and children

Contemporary outcomes for functional single ventricle with total anomalous pulmonary venous connection

OBJECTIVE

In 2004, we reported improved early survival for patients with functional single ventricle anatomy and total anomalous pulmonary venous connection. This study sought to discover if outcomes have been ameliorated in the contemporary era.

METHODS

This was a single-center review of patients with single ventricle anatomy and total anomalous pulmonary venous connection who were admitted from 1984 to 2021. The cohort was divided into similarly sized groups by date of admission: Era 1: 1984 to 1992, Era 2: 1993 to 2007, and Era 3: 2008 to 2021. Survival was compared, and Cox proportional hazards models were used to evaluate the likelihood of mortality.

RESULTS

We included 190 patients with single ventricle anatomy and total anomalous pulmonary venous connection. Unbalanced atrioventricular canal defect (70%) was the most common primary diagnosis. The most common type of total anomalous pulmonary venous connection was supracardiac (49%). Approximately one-third (32%) of patients had pulmonary venous obstruction. There were no significant differences in patient characteristics across eras. Early survival after initial palliative operation improved between Eras 1 and 2, and then remained stable in Era 3. Overall survival improved from Era 1 to Eras 2 and 3 (P < .001), but not between Era 2 and 3. Survival to 10 years by Eras 1 to 3 was 15%, 51%, and 54%, respectively. The anatomic features associated with worse survival were hypoplastic left heart syndrome diagnosis (hazard ratio, 1.60; 1.04-2.57) and pulmonary venous obstruction (hazard ratio, 1.80; 1.24-2.69).

CONCLUSIONS

Overall survival for patients with single ventricle anatomy and total anomalous pulmonary venous connection has plateaued since the early 2000s. Even in the most recent era, survival to age 10 years remains less than 60%. Risk factors for mortality include the diagnosis of hypoplastic left heart syndrome and pulmonary venous obstruction. Further studies should focus on identification of the pathophysiological factors underlying the increased mortality.

Persistent pulmonary hypertension of the newborn: pathogenesis, etiology, and management

Persistent pulmonary hypertension of the newborn (PPHN) is characterized by severe hypoxemia shortly after birth, absence of cyanotic congenital heart disease, marked pulmonary hypertension, and vasoreactivity with extrapulmonary right-to-left shunting of blood across the ductus arteriosus and/or foramen ovale. In utero, a number of factors determine the normally high vascular resistance in the fetal pulmonary circulation, which results in a higher pulmonary compared with systemic vascular pressure. However, abnormal conditions may arise antenatally, during, or soon after birth resulting in the failure of the pulmonary vascular resistance to normally decrease as the circulation evolves from a fetal to a postnatal state. This results in cyanosis due to right-to-left shunting of blood across normally existing cardiovascular channels (foramen ovale or ductus arteriosus) secondary to high pulmonary versus systemic pressure. The diagnosis is made by characteristic lability in oxygenation of the infant, echocardiographic evidence of increased pulmonary pressure, with demonstrable shunts across the ductus arteriosus or foramen ovale, and the absence of cyanotic heart disease lesions. Management of the disease includes treatment of underlying causes, sedation and analgesia, maintenance of adequate systemic blood pressure, and ventilator and pharmacologic measures to increase pulmonary vasodilatation, decrease pulmonary vascular resistance, increase blood and tissue oxygenation, and normalize blood pH. Inhaled nitric oxide has been one of the latest measures to successfully treat PPHN and significantly reduce the need for extracorporeal membrane oxygenation.

Effect of oversizing cardiac allografts on survival in pediatric patients with congenital heart disease

BACKGROUND

There are few published data regarding the long-term outcome of "large" cardiac allografts in children. This study examines the effect of cardiac graft oversizing on the survival of pediatric patients with congenital heart disease (CHD).

METHODS

Two hundred ninety-one children, age 1 day to 17 years (median 50 days), with CHD underwent primary cardiac transplantation between 1985 and 2002. Patients were analyzed according to donor-recipient weight ratio (D-R): Group (Gp) I (n = 252) with D-R <2.5 (range 0.59 to 2.49, median 1.4), and Gp II (n = 39) with D-R >/=2.5 (range 2.5 to 4.65, median 2.78). CHD diagnoses included hypoplastic left heart syndrome (138 in Gp I, 13 in Gp II), single ventricle (29 in Gp I, 1 in Gp II) and other (85 in Gp I, 13 in Gp II). Patients with cardiomyopathy were excluded. Pre-transplant cardiac palliation was performed in 36% of Gp I and 15% of Gp II patients. The average graft ischemic times (minutes) were 266 +/- 7.5 and 283 +/- 18.9 for Gp I and Gp II, respectively (p < 0.2).

RESULTS

The operative mortality for Gp I was 10.3% and 10.2% for Gp II (p < 0.99). There was no significant difference between the 2 groups in length of hospital stay (p < 0.15) or duration of ventilator support (p < 0.6) post-transplantation. However, the incidence of open chest was higher (p < 0.003) in Gp II (28%) compared with Gp I (8%). The survival rates for Gp I and Gp II were: 82 +/- 2.4% vs 84 +/- 5.7% at 1 year; 71 +/- 2.9% vs 72 +/- 7.2% at 5 years; and 63 +/- 3.2% vs 65% +/- 7.4 at 10 years.

CONCLUSIONS

Post-transplant morbidity and short- and long-term survival of pediatric recipients with CHD are not adversely influenced by the use of oversized cardiac allografts.

Heart transplantation in children and infants: short-term outcome and long-term follow-up

Since 1988, 82 heart transplants have been performed in 80 infants and children. Diagnoses pretransplant were: hypoplastic left heart syndrome (HLHS) (n = 43); cardiomyopathy (n = 19); endocardial fibroelastosis (n = 6); and other complex congenital heart diseases (n = 12). Age at transplantation was < 1 yr in 61 patients. Overall survival rate was 79% at 1 yr and 73% at 5 and 10 yr. To date, 20 patients have died after transplantation. Causes of death were: rejection (eight patients); right ventricular failure (four patients); transplant coronary artery disease (TCAD) (two patients); and other causes (six patients). In the majority of patients somatic growth is not impaired, and renal function is reduced (but stable) in all patients. Two patients developed post-transplant lymphoproliferative disease, which was treated successfully. Major long-term morbidity is neurologic deficit - severe in three patients and minor in six. TCAD was present or suspected in six surviving patients. We conclude that heart transplantation in infants and children can be performed with good early and late results. Quality of life is excellent in most patients. TCAD, however, will become an increasing problem in the long term.

Cardiomyopathy and heart transplantation in children

Cardiomyopathy is one of the most common causes of death in children with heart disease. Increasingly, dilated cardiomyopathy is recognized to be familial, and specific gene products related to the myocyte cytoskeleton and contractile proteins have been identified. Other associations with metabolic disease, dysmorphic syndromes, and neuromuscular disease are important to establish, particularly in pediatric patients, to guide therapy and patient selection for transplantation. Survival in children with dilated cardiomyopathy depends on accurate diagnosis and aggressive therapy. Patients may respond to conventional treatment for heart failure or may deteriorate, requiring mechanical support. Extracorporeal membrane oxygenation has been used effectively for mechanical support in children until improvement occurs or as a bridge to transplantation. For those who are listed, the mortality rate while waiting for a donor organ averages approximately 20%. Survival after transplantation is good, with an intermediate survival rate of approximately 70%. Late survival remains to be determined in the current cyclosporin era but may in fact be improving. However, increased organ donation or strategies to increase the size of the organ donor pool, such as xenotransplantation, are needed to significantly reduce the rate of mortality while waiting.

Survival after listing for cardiac transplantation in children

Despite improvement in surgical and medical management of children with congenital and acquired heart disease, cardiac transplantation remains an important therapeutic option for infants and children with end-stage heart disease. Ultimate survival in patients who are listed for transplantation is a function of both mortality while awaiting transplantation and survival after transplantation. Survival of heart transplantation is affected by the severity of illness before transplantation, the unique pathophysiology of certain defects, and the availability of donor hearts. Outcome following listing for transplantation is best studied with the use of recent modifications in statistical methods of competing outcomes analysis. By this analysis a predicted mortality while waiting among all pediatric patients is 20% at 1 year, with 67% undergoing transplantation, 10% still on the list awaiting transplant, and 3% removed from the list. Among infants, most of them with hypoplastic left heart syndrome, 60% will have transplantation by 6 months after listing, with 27% of patients dying while waiting. In infants the major risk factors for death while waiting are the need for inotropic support at listing, smaller size, and recipient blood type. In older children risk factors for death while waiting are Status 1 at listing and a need for mechanical ventilation. Intermediate-term survival after transplant is excellent in all age groups with 86% alive at 6 months, 84% at 1 year, and 73% at 5 years. Survival after transplant in infants is comparable to survival in older children, although the early mortality after transplantation is greater. Infants who have recently undergone sternotomy or received organs from donors who did not die of closed head trauma are more likely to die early after transplant. Among older children risk factors for death after transplantation include the need for a mechanical support device or a younger age in patients greater than 1 year of age. Death following transplantation is primarily related to early graft failure in infants, whereas rejection, infection, and sudden death account for the majority of deaths in older children. Although improved immunosuppressive agents promise to lead to even better survival rates after transplantation, greater access to donors is essential if overall survival is to be improved.

Infant heart transplantation: improved intermediate results

OBJECTIVES

Our objectives were to (1) review our experience with heart transplants in infants (age < 6 months), (2) delineate risk factors for 30-day mortality, and (3) compare outcomes between our early and recent experience.

METHODS

Records of all infants listed for transplantation in our center before September 1996 were analyzed. Early and recent comparisons were made between chronologic halves of the accrual period. Univariate analysis was used to analyze potential risk factors for 30-day mortality (categorical variables, Fisher's exact test; continuous variables, nonparametric Wilcoxon rank-sum test). Multivariable analysis included univariate variables with p values < or = 0.10. Actuarial survivals were estimated (Kaplan-Meier) and compared by the log-rank test.

RESULTS

Fifty-one of the 60 infants listed for transplantation were operated on (waiting list mortality 15%). Thirty-day mortality was 18% overall, 30% in the first 3 years and 10% in the last 3 years (p = 0.07). Sepsis was the commonest cause of early death (4/9). Univariate analysis suggested four potential risk factors for early death: preoperative mechanical ventilation (p = 0.01), prior sternotomy (p = 0.002), preoperative inotropic drugs (p = 0.08), and warm ischemia time (p = 0.08). Multivariable analysis indicated that prior sternotomy (p = 0.01) was an independent risk factor for 30-day mortality. Actuarial survivals were 80%, 78%, and 70% at 1, 2, and 3 years, and these figures improved between early and recent groups (p = 0.05). Late deaths were most commonly due to acute rejection (3/5).

CONCLUSIONS

Results of heart transplantation in infancy improve with experience. Prior sternotomy increases initial risk. Intermediate-term survival for infants with end-stage heart disease is excellent.

Surgical management of hypoplastic left heart syndrome

BACKGROUND

The treatment of infants with hypoplastic left heart syndrome has been challenging and controversial.

METHODS

To assess the operative management and intermediate-term outcome, we retrospectively analyzed our surgical experience with 50 newborns with hypoplastic left heart syndrome operated on between January 1989 and June 1995.

RESULTS

Surgical palliation with a first-stage Norwood operation was offered to 28 patients. The remaining 22 infants were initially listed for heart transplantation, and 15 underwent the operation. Ten of the 15 recipients are alive, and all are in New York Heart Association class I. Seven infants underwent a Norwood procedure after being on the list for transplantation for 12 to 42 days. A total of 34 patients underwent Norwood procedures with one operation aborted because of inoperable anatomy. Two infants who survived the first-stage Norwood operation underwent subsequent heart transplantation and are currently doing well. The 1-year mortality rate for heart transplantation was 18% (3/17) versus 50% (17/34) for the Norwood procedure. Risk factors for early mortality after a Norwood procedure include longer circulatory arrest time (> 50 minutes), preoperative acidosis (pH < 7.20), larger systemic-pulmonary artery shunt (> or = 4 mm), diminutive ascending aorta (< or = 2.0 mm), and anatomic subtype of aortic and mitral atresia. The 1-year survival rate for the Norwood procedure improved from 36% for the patients operated on during 1989 through 1992 to 75% during 1993 to mid-1995 (p = 0.005). Of the 17 survivors of a first-stage Norwood operation, 10 have undergone the second stage (bidirectional Glenn procedure), and 7 have completed a Fontan procedure. Heart transplantation results have also improved, with no deaths since 1992.

CONCLUSIONS

Both the Norwood procedure and heart transplantation have encouraging early to intermediate results in infants with hypoplastic left heart syndrome. Hypoplastic left heart syndrome should be managed selectively on the basis of cardiac morphology, donor availability, and family wishes. Development of a flexible program involving the use of both procedures may aid in the successful management of infants with hypoplastic left heart syndrome.

Transplantation as a primary treatment for hypoplastic left heart syndrome: intermediate-term results

BACKGROUND

Hypoplastic left heart syndrome is a lethal malformation. For the last 10 years, orthotopic cardiac transplantation has been our preferred treatment for infants with hypoplastic left heart syndrome.

METHODS

One hundred seventy-six infants with hypoplastic left heart syndrome were entered into a cardiac transplant protocol between November 1985 and November 1995. Interventional procedures to stent the ductus arteriosus or enlarge the interatrial communication were performed in 8 and 35 patients, respectively. Thirty-four patients (19%) died during the waiting period, and 142 infants underwent cardiac transplantation. Age at cardiac transplantation ranged from 1.5 hours to 6 months (median, 29 days). The majority of grafts were oversized, and the median graft ischemic time was 273 minutes (range, 60 to 576 minutes). The implantation procedure used a period of hypothermic circulatory arrest ranging from 23 to 110 minutes (median, 53 minutes). Repair of other significant defects included interrupted aortic arch and total or partial anomalous pulmonary venous connection.

RESULTS

There were 13 early and 22 late deaths. Patient actuarial survival at 1 month and at 1, 5 and 7 years was 91%, 84%, 76%, and 70% respectively. Half of the late deaths were due to rejection. Severe graft vasculopathy was confirmed in 8 patients. Retransplantation was performed in 5 patients for graft vasculopathy 4 and rejection 1. Lymphoblastic leukemia developed in 1 patient 3 years after cardiac transplantation.

CONCLUSIONS

Cardiac transplantation can be performed in infants with hypoplastic left heart syndrome with good operative and intermediate-term results. Improved survival can be achieved with increased donor availability, better management of rejection, and control of graft vasculopathy.

Doppler echocardiographic analysis of flow in the ductus arteriosus of infants with hypoplastic left heart syndrome: relationship of flow patterns to systemic oxygenation and size of interatrial communication

Excessive pulmonary overcirculation related to imbalance in the pulmonary/systemic vascular resistance ratio contributes to hemodynamic instability in infants with the hypoplastic left heart syndrome. Because the ductus arteriosus bridges the two vascular circuits in this lesion, we studied the Doppler echocardiographic flow patterns in the ductus arteriosus of 50 infants with hypoplastic left heart syndrome to investigate their relationship to the degree of pulmonary blood flow as measured by simultaneously obtained levels of partial pressure of oxygen in arterial blood. The degree of restriction to pulmonary venous egress as determined by size of the interatrial communication was also correlated with ductal flow patterns and partial pressure of oxygen in arterial blood. Biphasic flow was noted in all infants. Mean peak velocity of antegrade flow (pulmonary artery to aorta) was greater than that of retrograde flow (aorta to pulmonary artery) (131 +/- 45 cm/sec versus 54 +/- 15 cm/sec; p < 0.001), mean time of retrograde flow was greater than that of antegrade flow (246 +/- 60 msec versus 174 +/- 28 msec; p < 0.001), and mean velocity-time integral of antegrade flow was greater than that of retrograde flow (13.3 +/- 4.8 cm versus 6.3 +/- 3.4 cm; p < 0.001). The ratio of velocity-time integral of retrograde flow/antegrade flow (a volumetric estimate of diastolic reversal into the pulmonary vascular bed indexed to systemic output) correlated extremely well with partial pressure of oxygen in arterial blood (r = 0.91; p < 0.0001). Categoric size of the interatrial communication (none, n = 2; small [<2 mm], n = 9; moderate [3 to 4 mm], n = 23; and large [>4 mm], n = 16) correlated with partial pressure of oxygen in arterial blood (r = 0.82; p < 0.001); the smaller the interatrial communication the lower the partial pressure of oxygen in arterial blood and velocity-time integral ratio of retrograde/antegrade flow. Doppler flow patterns in the ductus arteriosus of infants with hypoplastic left heart syndrome are reflective of the resistance ratio between the pulmonary and systemic vascular circuits and may be helpful in monitoring the hemodynamics of these infants.