Unsuspected congenital heart disease in neonates receiving extracorporeal life support: a review of ninety-five cases from the Extracorporeal Life Support Organization Registry

Contemporary outcomes in infants with congenital heart disease and bochdalek diaphragmatic hernia

BACKGROUND

Fifteen percent of infants with congenital diaphragmatic hernia (CDH) are born with a coexisting cardiac anomaly. The purpose of this study was to evaluate contemporary outcomes in this patient population and to identify potential risk factors for in-hospital mortality.

METHODS

Data from all CDH neonates with congenital heart disease managed at a single pediatric tertiary care referral center between 1997 and 2011 were retrospectively analyzed.

RESULTS

Forty (18%) of 216 CDH patients had a cardiac anomaly. This group was associated with a significant decrease in overall survival when compared with patients without cardiac anomaly (55% versus 81%; p = 0.001). There was no association between type of cardiac anomaly and mortality based on risk stratification according to the Risk Adjustment for Congenital Heart Surgery and The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery scoring systems (p = 0.86 and p = 0.87, respectively). Birth weight was similarly no different between survivors and nonsurvivors (2.8 ± 0.6 kg versus 2.8 ± 0.9 kg, respectively; p = 0.98). There was a trend toward increased extracorporeal membrane oxygenation use among nonsurvivors (p = 0.13). Infants with hemodynamic stability enabling subsequent cardiac repair were associated with lower mortality (p = 0.04). Survivors had a wide spectrum of long-term morbidity, but most had some evidence of neurodevelopmental impairment.

CONCLUSIONS

This large single-institution series suggests that the overall prognosis of infants with concomitant CDH and congenital heart disease can be quite variable, regardless of the type of heart anomaly. Hemodynamic instability and need for extracorporeal membrane oxygenation correlate with higher mortality. Although some long-term survivors have excellent outcomes, most suffer from chronic, long-term morbidities.

Management of the sick neonate with suspected heart disease

A proportion of symptomatic neonates with congenital heart disease have lesions requiring urgent stabilisation. Despite increasing antenatal diagnoses, the importance of early recognition of symptomatic neonates is highlighted by the fact that up to 10% of all deaths in congenital heart disease continue to occur in children undiagnosed at the time of death. Specific anatomical knowledge of the many complex lesions is not required for good early management. The focus of this article is the specific symptom complexes in critically ill neonates with congenital heart disease, initial management strategies for stabilization and transfer to specialist centres, and issues in the ongoing preoperative care.

Outcome in neonates with congenital heart disease referred for respiratory extracorporeal membrane oxygenation

AIM

To evaluate the proportion of neonates referred for extracorporeal membrane oxygenation (ECMO) support in the modern era of advanced conventional treatments for respiratory failure who actually had congenital heart disease (CHD), and to assess the impact of this diagnostic route on patient condition and outcome.

METHODS

A retrospective case-note review of neonatal ECMO and cardiac admissions to a single, tertiary ECMO and cardiac intensive care unit (ICU) between March 1999 and February 2002.

RESULTS

287 symptomatic neonates presented to the ICU with previously undiagnosed cardiac or respiratory disease. Eighty-two with presumed respiratory failure were referred for ECMO, and 205 with suspected CHD were referred for cardiac evaluation. Eight (10%) ECMO referrals, all with presumed persistent pulmonary hypertension of the newborn (PPHN), were found to have CHD (transposition: 3; total anomalous pulmonary venous connection: 3; left heart obstructive lesions: 2). Mortality in this group was 50%, compared with 11% for correctly identified CHD patients (odds ratio 8.2, 95% CI 1.92, 35.4, p<0.01). For all neonates with CHD, the risk of death was increased by the presence of cardiovascular collapse and end-organ dysfunction at presentation to the ICU (p<0.01 for both).

CONCLUSION

Neonates with CHD may present as severe "PPHN" via the ECMO service. Poor outcome in these patients relates to the high incidence of cardiovascular collapse and end-organ dysfunction. Early echocardiography is recommended for neonates with presumed PPHN. Neonatal ECMO support should be based in centres with cardiac surgical services.

Venovenous versus venoarterial extracorporeal life support for pediatric respiratory failure: are there differences in survival and acute complications?

OBJECTIVES

To examine the Extracorporeal Life Support Organization (ELSO) registry database of infants and children with acute respiratory failure to compare outcome and complications of venovenous (VV) vs. venoarterial (VA) Extracorporeal Life Support (ECLS).

DESIGN

Retrospective cohort study.

SETTING

ELSO registry for pediatric pulmonary support.

PATIENTS

All nonneonatal pediatric pulmonary support ECLS cases treated at U.S. centers and reported to the ELSO registry as of July 1997. Patients were excluded if they had one or more of the following diagnoses: hematologic-oncologic, cardiac, abdominal surgical, burn, metabolic, airway, or immunodeficiency disorder.

INTERVENTIONS

Venoarterial or venovenous extracorporeal life support for severe pulmonary failure.

MEASUREMENTS AND MAIN RESULTS

From 1986 to June of 1997, 763 pediatric patients met the inclusion criteria. Overall, 595 were initially managed with VA bypass, and 168 with VV bypass. The VA group was younger (mean +/- SD, 26.1+/-42.2 months for VA vs. 63.5+/-68.7 months for VV) and smaller (11.8+/-15.1 kg vs. 22.9+/-23.8 kg) (p<.001). There were no differences between groups in number of days on mechanical ventilation before ECLS, number of hours on ECLS, or number of hours on mechanical ventilation post-ECLS in survivors. Mean pH and Paco2 values, positive end-expiratory pressure, and mean airway pressure just before placing the patient on ECLS were also similar. VA-treated patients had higher Fio2 requirements (p = .034), lower Pao2 (p = .047), and lower Pao2/Fio2 ratio (p = .014) just before cannulation. There was a trend of higher peak inspiratory pressure in VA-treated patients (p = .053). Overall, survival rate was not different for the two groups (55.8% for VA vs. 60.1% for VV; p = .33). Central nervous system complications were not different between the two groups. Examination of the same variables was then conducted after dividing the patients into four subgroups. There were no significant differences in survival or complications during bypass between VV and VA modes of ECLS in any subgroup. Stepwise logistic regression modeling was performed to control for variables associated with the outcome survival for VV and VA-treated groups, and variables measured before bypass were identified as being associated with improved survival. There was a trend of improved survival in the VV-treated patients (p = .12).

CONCLUSIONS

Overall survival of pediatric patients with acute respiratory failure supported by VA or VV ECLS was comparable. A randomized clinical trial may be useful in clarifying these observations.

Pediatric cardiac extracorporeal membrane oxygenation in congenital heart disease: the cardiologist's view

There is no doubt that extracorporeal membrane oxygenation (ECMO) as a powerful therapeutic modality in critically ill newborn infants and older children with congenital heart disease has implications for the pediatric cardiologist. His responsibilities as consultant in the intensive care unit include screening for unsuspected cyanotic heart disease in neonatal candidates referred for ECMO and appraisal of surgical repair in postcardiotomy patients as well as assessment of postoperative hemodynamics and detection of complications during perfusion. A close cooperation between intensive care specialists and other appropriate specialists (pediatric cardiologists, cardiac surgeons, and anesthesiologists) is required for the process of decision making prior to initiation of postoperative ECMO in the individual patient with congenital heart disease. Long-term survival, morbidity, cerebrovascular complications, and neurodevelopmental sequelae of these near miss children remain a critical issue. Furthermore, there is a strong need for professional psychosocial support of affected parents, both in the hospital and after discharge.

Extracorporeal membrane oxygenation in infants with congenital diaphragmatic hernia and cardiac malformations

Since the introduction of neonatal extracorporeal membrane oxygenation (ECMO) in Canada, the authors have treated three infants with congenital diaphragmatic hernia (CDH) who had serious congenital cardiac anomalies (among 26 infants with CDH treated with ECMO). To determine the incidence of and outcome for infants with combined lesions who received ECMO, 19 years' data (April 1973 to October 1992) from the Extracorporeal Life Support Organization (ELSO) registry were reviewed. Seventeen infants with combined cardiac and diaphragmatic lesions were registered as receiving ECMO in the United States or Canada. Thus, the incidence of combined cardiac and diaphragmatic lesions was 2.5 per thousand neonates (17 of 6,295) receiving ECMO and 13 per thousand neonates (17 of 1,318) receiving ECMO for CDH. Five (29.4%) of the 17 infants survived. A congenital cardiac lesion may not be an absolute contraindication to ECMO in infants with CDH. Decisions to cannulate for ECMO should be based on the potential outcome of the underlying cardiac defect.

Complications of neonatal extracorporeal membrane oxygenation

From 1973-1985 to 1988 the average patient complications per case were 1.44 per case and significantly increased during 1990 to 1992 to 2.10 per case (Figure 3). During the same periods patient survival significantly decreased from 84% (1973-1985 to 1988, n = 2463) to 80% (1990 to 1992, n = 4005) (Figure 4). The association between total complication rates and survival rate was examined by regression analysis (Table 5). The correlation of patient complication rate and total complication rate with survival is highly significant; however, causality cannot be established. When comparing different entry criteria (Table 2) for incidence of mechanical and patient complications, no significant differences are apparent. This is not surprising since each of the entry criteria were designed to identify the same patient population. When premature neonates (> 35 weeks) were placed on ECMO, 36% of them had intracranial haemorrhage (ICH) with 62% mortality while only 12% of the neonates < 35 weeks had ICH and a 49% mortality. Similar findings were noted with low birthweight neonates (< 2.2 kg), 28% had ICH with 64% mortality while only 12% of the neonates > 2.2 kg had ICH with a 50% mortality. Selection criteria remain problematic for a variety of reasons. They cannot be viewed as absolute because of variability between centres. What represents likely 80% mortality in one centre may not apply to another. Historical controls are misleading because changing respiratory therapy strategies make historical populations difficult to compare. Also, once an ECMO centre becomes established, a more challenging group of patients will be attracted than previously was the case. Further, a single entry criterion cannot be generalized for all entry diagnoses. Criteria for an 80% predicted mortality is probably not the same for MAS, CHN, PPHN, and sepsis. Subsequent patients registered in the Neonatal ECMO Registry of the Extracorporeal Life Support Organization will address these issues more thoroughly, as specific details of the pre-ECMO condition and therapeutic strategies are collected. This collective review should help to identify trends which require reassessment of technique or patient management.