Modified Norwood operation for hypoplastic left heart syndrome

Postoperative course in the cardiac intensive care unit following the first stage of Norwood reconstruction

The medical records of all patients born between 1 September, 2000, and 31 August, 2002, and undergoing the first stage of Norwood reconstruction, were retrospectively reviewed for details of the perioperative course. We found 99 consecutive patients who met the criterions for inclusion. Hospital mortality for the entire cohort was 15.2%, but was 7.3%, with 4 of 55 dying, in the setting of a "standard" risk profile, as opposed to 25.0% for those with a "high" risk profile, 11 of 44 patients dying in this group. Extracorporeal membrane oxygenation was utilized in 7 patients, with 6 deaths. Median postoperative length of stay in the hospital was 14 days, with a range from 2 to 85 days, and stay in the cardiac intensive care unit was 11 days, with a range from 2 to 85 days. Delayed sternal closure was performed in 18.2%, with a median of 1 day until closure, with a range from zero to 5 days. Excluding isolated delayed sternal closure, and cannulation and decannulation for extracorporeal support, 24 patients underwent 33 cardiothoracic reoperations, including exploration for bleeding in 12, diaphragmatic plication in 4; shunt revision in 4, and other procedures in 13. The median duration of total mechanical ventilation was 4.0 days, with a range from 0.7 to 80.5 days. Excluding those who died, the median total duration of mechanical ventilation was 3.8 days, with a range from 0.9 to 46.3 days. Reintubation for cardiorespiratory failure or upper airway obstruction was performed in 31 patients. Postoperative electroencephalographic and/or clinical seizures occurred in 13 patients, with 7 discharged on anti-convulsant medications. Postoperative renal failure, defined as a level of creatinine greater than 1.5 mg/dl, was present in 13 patients. Eleven had significant thrombocytopenia, with fewer than 20,000 platelets per microl, and injury to the vocal cords was identified in eight patients. Risk factors for longer length of stay included lower Apgar scores, preoperative intubation, early reoperations, reintubation and sepsis, but not weight at birth, genetic syndromes, the specific surgeon, or the duration of surgery. Although mortality rates after the first stage of reconstruction continue to fall, the course in the intensive care unit is remarkable for significant morbidity, especially involving the cardiac, pulmonary and central nervous systems. These patients utilize significant resources during the first hospitalization. Further studies are necessary to stratify the risks faced by patients with hypoplasia of the left heart in whom the first stage of Norwood reconstruction is planned, to determine methods to reduce perioperative morbidity, and to determine the long-term implications of short-term complications, such as diaphragmatic paresis, injury to the vocal cords, prolonged mechanical ventilation, and postoperative seizures.

Outcomes after bidirectional Glenn operation: Blalock-Taussig shunt versus right ventricle-to-pulmonary artery conduit

BACKGROUND

There are distinct physiologic differences between patients with single-ventricle lesions who have undergone the Norwood procedure with a right ventricle-to-pulmonary artery conduit (NW-RVPA) compared with those patients who have undergone the Norwood operation with a Blalock-Taussig shunt (NW-BTS). We evaluated bidirectional Glenn operation outcomes and compared the two groups to assess whether the type of Norwood operation influenced outcomes.

METHODS

A retrospective chart review compared bidirectional Glenn operation outcomes for children undergoing the Norwood operation with NW-RVPA or NW-BTS at Children's Hospital Boston from January 1, 2002, to December 31, 2003.

RESULTS

Of 80 patients undergoing the Norwood operation, 56 (NW-BTS, 27 versus NW-RVPA, 29) returned for the bidirectional Glenn operation at our institution. The NW-RVPA group had a lower median age at presentation for bidirectional Glenn (4.5 months versus 5.8 months; p = 0.01), but had better weight gain (20.6 g/day versus 16.5 g/day; p = 0.03) than the NW-BTS group. No interstage deaths occurred in the NW-RVPA group. There were no differences in morbidity or mortality after the BDG between the two groups.

CONCLUSIONS

There were no differences in morbidity and mortality outcomes after the bidirectional Glenn operation between the NW-RVPA and NW-BTS groups. Despite younger age at presentation, the NW-RVPA patients had better growth rate, which may have contributed to the similar postoperative outcomes.

Stage I palliation for hypoplastic left heart syndrome: Norwood versus Sano modification

PURPOSE OF REVIEW

Advancements in surgical technique and perioperative care have significantly improved the survival of infants born with hypoplastic left heart syndrome. A recent modification to the Norwood procedure is being adopted by many centers to improve postoperative hemodynamic stability and survival to stage II palliation. The late effects of this modification, however, are speculated and have not been investigated.

RECENT FINDINGS

Center-specific improved short-term outcomes have been reported in a few small, nonrandomized studies of a new approach to the Norwood procedure, which utilizes a right ventricle to pulmonary artery shunt or Sano modification to provide pulmonary blood flow rather than the standard modified Blalock-Taussig shunt.

SUMMARY

The classic Norwood procedure and Sano modification each have specific advantages and disadvantages in both the short and long term. Data comparing the two techniques are nonrandomized, contradictory, and utilize historical controls. The optimal shunt to improve survival to the second-stage palliation is unknown. A multicenter randomized clinical trial comparing the Sano with the modified Blalock-Taussig shunt in hypoplastic left heart syndrome or variants is currently in progress and should hopefully provide future guidelines for shunt selection based on clinical presentation.

Intensive care course after stage 1 Norwood procedure: are there early predictors of failure?

OBJECTIVE

The purpose of this study was to review the early postoperative course of stage 1 Norwood with Blalock-Taussig shunt (BTS) or right ventricle-to-pulmonary artery conduit (RVPA) and to identify early predictors of failure.

MATERIAL AND METHODS

A retrospective analysis was conducted in 33 consecutive neonates who underwent BTS (n=19) or RVPA (n=14) stage 1 Norwood procedure between 2000 and 2005. Pre-, peri-, and postoperative data included: hourly hemodynamics and blood gases, pulmonary to systemic flow ratio, duration of mechanical ventilatory and inotrope support, intensive care and hospital stay. Failure was defined as death or transplantation.

RESULTS

Thirteen patients failed the procedure (39.4%): 10 BTS (52.6%) and 3 RVPA (21.4%). Failure decreased from 61.1% in 2000-2002 to 13.3% in 2003-2005 and was associated with: low systolic, mean and diastolic blood pressure, urine output, pH, base excess, bicarbonates, and high pulmonary to systemic flow ratio within 24 h postoperatively. Arterial oxygen and CO2 pressure, and oxygen saturation did not differ with failure. RVPA had higher diastolic blood pressure and more stable hemodynamics despite similar pulmonary to systemic flow ratio. Duration of mechanical ventilation, inotrope support, intensive care stay were shorter in RVPA. Postoperative echographic ventricular dysfunction and tricuspid regurgitation grade were correlated with failure.

CONCLUSIONS

Excessive pulmonary to systemic flow ratio and low blood pressure are associated with failure. High diastolic blood pressure more than low pulmonary to systemic flow ratio seems to account for more favorable outcomes in RVPA compared to BTS procedure.

Extracorporeal life support after staged palliation of a functional single ventricle: Subsequent morbidity and survival

OBJECTIVE

We sought to review the outcome of infants with a functional single ventricle receiving postoperative extracorporeal life support.

METHODS

We reviewed all patients with a functional single ventricle receiving postoperative extracorporeal life support between January 1997 and May 2003.

RESULTS

We supported 25 infants (age range, 2-139 days; median age, 15 days; weight range, 1.9-5.9 kg; median weight, 3.4 kg) with extracorporeal life support. Operative procedures were Norwood stage 1 procedure in 18 patients, modified Blalock-Taussig shunt in 4 patients, bidirectional superior cavopulmonary shunt in 2 patients, and pulmonary vein repair in 1 patient. Indications for extracorporeal life support included cardiac arrest (14/25) and low cardiac output state (11/25). Extracorporeal membrane oxygenation was initiated in 19 patients, with conversion to a ventricular assist device in 7 patients. Ventricular assist device alone was initiated in 6 patients. Survival to decannulation was 76%, with 5 late deaths from multiorgan failure and 56% intensive care unit survival. Survival to hospital discharge was 44%. On univariate analysis, the presence of arrhythmia before extracorporeal life support (P = .005), renal failure (P = .0007), Candida species-induced sepsis (P = .026), and multiorgan failure (P = .0009) were significant risk factors in the nonsurvivors. Median hospital stay was 43.5 days (range, 6-181 days) for the whole group and 93 days (range, 36-181 days) for survivors. Eight patients completed next stage palliation.

CONCLUSIONS

Twenty percent of patients were supported with a ventricular assist device alone, with 50% conversion to a ventricular assist device from extracorporeal membrane oxygenation. Survival to decannulation was encouraging. Multiorgan failure and risk of invasive infection in the post-extracorporeal membrane oxygenation period mitigate against survival to hospital discharge. Use of extracorporeal life support before cardiac arrest might reduce attrition between decannulation and hospital discharge.

A risk assessment scoring system predicts survival following the Norwood procedure

No one set of characteristics has been consistently predictive of perioperative mortality and morbidity associated with the Norwood procedure. The purpose of the current study is to further validate a scoring system shown to be predictive of mortality following the Norwood procedure. We performed a retrospective review of all infants with the diagnosis of hypoplastic left heart syndrome (HLHS) who underwent the Norwood procedure at St. Louis Children's Hospital from July 1, 1994, to December 31, 2002. A weighted score for each of six factors comprised the scoring system. The factors included ventricular function, tricuspid regurgitation, ascending aortic diameter, atrial septal defect blood flow characteristics, blood type, and age. A score of > or = 7 points indicated lower reconstructive mortality risk, and a total score of < 7 points indicated a higher mortality risk. A total of 57 patients were analyzed. Twenty-five infants (44%) had a low risk score. These infants had a significantly greater survival at 48 hours compared to infants with a score of < 7 (92 vs 75%, p < 0.05). Infants with a high risk score had a significantly greater relative risk of mortality at 48 hours [OR = 2.04; confidence interval (CI) 1.04-4.00; p = 0.036]. The area under the receiver operating characteristic (ROC) curve is 0.8534 (95% CI, 0.78-0.922). This suggests that the scoring system has a very good degree of discriminatory power in selecting children who did not survive. Based on the results of the ROC, a cutoff score of >7 gives the best sensitivity and specificity for survival. When applied retrospectively, the survival outcomes predicted by our scoring system significantly correlated with actual outcomes. This supports the conclusion that a specific population of HLHS patients may have a higher mortality risk independent of surgical technique and postoperative care based on factors that can be assessed preoperatively.

Clinical Outcomes of 84 Children with Congenital Heart Disease Managed with Extracorporeal Membrane Oxygenation after Cardiac Surgery

The purpose of our research was to study the clinical outcomes of children with congenital heart disease (CHD) requiring extracorporeal membrane oxygenation (ECMO) support after cardiac surgery at a tertiary care children's hospital. Retrospective review of all patients with CHD who required postcardiotomy ECMO between January 2001 and September 2004 (45 months) was undertaken. Various outcome predictors were tested for any association with survival to hospital discharge using univariate analysis. A total of 84 children were placed on ECMO after CHD surgery; 39 (46.4%) were placed on ECMO in the operating room. Median age of the patients was 128 days (1 day to 5 years) and median weight was 4.53 kg (2-18 kg). Active cardiopulmonary resuscitation was ongoing at the time of cannulation in 27 children (32%). Fifty-two children (61.9) survived > 24 hours after decannulation and 31 (36.9%) survived to discharge. High arterial serum lactate levels at the time of ECMO initiation were strongly correlated with nonsurvival (p = 0.004). Nonsurvivors had longer duration on ECMO than survivors (p = 0.003). The odds of survival dropped significantly after 144 hours (day 6) of ECMO. ECMO support results in improved outcomes in patients who suffered hemodynamic collapse post cardiac surgery. Underlying cardiac lesion, age, weight, gender, initial arterial pH, location of ECMO initiation, need for hemofiltration and placement of ECMO after active ongoing cardiopulmonary resuscitation did not increase the mortality risk. Initial arterial serum lactate level and inability to wean off by 6 days were strongly correlated with nonsurvival.

Risk factors for mortality in 137 pediatric cardiac intensive care unit patients managed with extracorporeal membrane oxygenation

OBJECTIVE

To identify factors associated with mortality in children with heart disease managed with extracorporeal membrane oxygenation (ECMO).

DESIGN

Retrospective chart review.

SETTING

Tertiary care university-affiliated children's hospital.

PATIENTS

All pediatric cardiac intensive care unit patients managed with ECMO between January 1, 1995, and June 30, 2001.

INTERVENTIONS

None.

RESULTS

During the study period, 137 patients were managed with ECMO in the pediatric cardiac intensive care unit. Of the 137 patients, 80 (58%) survived > or =24 hrs after decannulation, and 53 (39%) survived to hospital discharge. Patients managed with ECMO following cardiac surgery were analyzed separately from patients not in the postoperative period. Factors associated with an increased probability of mortality in the postoperative patients were age <1 month, male gender, longer duration of mechanical ventilation before ECMO, and development of renal or hepatic dysfunction while on ECMO. Single ventricle physiology and failure to separate from cardiopulmonary bypass were not associated with an increased risk of mortality. Cardiac physiology and indication for ECMO were not associated with mortality rate. Although longer duration of ECMO was not associated with increased mortality risk, patients with longer duration of ECMO were less likely to survive without heart transplantation.

CONCLUSIONS

In a series of 137 patients managed with ECMO in a pediatric cardiac intensive care unit, survival to hospital discharge was 39%. In postoperative patients only, mortality risk was increased in males, patients <1 month old, patients with a longer duration of mechanical ventilation before initiation of ECMO, and patients who developed renal or hepatic failure while on ECMO.

Hypoplastic left heart syndrome with intact or highly restrictive atrial septum: outcome after neonatal transcatheter atrial septostomy

BACKGROUND

Hypoplastic left heart syndrome (HLHS) with intact or very restrictive atrial septum is a highly lethal combination. We review our 13-year institutional experience treating this high-risk subgroup of patients with emergent catheter therapy.

METHODS AND RESULTS

Infants with HLHS requiring catheter septostomy within the first 2 days of life were compared with a matched control group with adequate interatrial communication. Preoperative, early postoperative, and medium-term survival were evaluated. Earlier experience was compared with recent results to assess the effect of changes in catheterization and surgical and intensive care unit management strategies over the study period. From 1990 to 2002, 33 newborns with HLHS (11% of newborns with HLHS managed during this period) underwent urgent/semiurgent catheterization to create or enlarge an interatrial communication before surgical palliation. Preoperative and early postoperative mortality were high (48%) compared with control HLHS patients, regardless of prenatal diagnosis and despite successful catheter-based atrial septostomy with clinical stabilization. Mortality trended down during the later part of the study period. Those who survived the neonatal period had late survival, pulmonary artery pressure, and resistance similar to those of control subjects.

CONCLUSIONS

Neonatal mortality in the subgroup of HLHS patients with intact or highly restrictive atrial septum remains high despite successful urgent septostomy. Persistently poor outcomes for these patients have prompted efforts at our center to develop techniques for fetal intervention for this condition, in the hope that prenatal relief of left atrial and pulmonary venous hypertension may promote normal pulmonary vascular and parenchymal development and improve both short- and long-term outcomes.

Achieving resonance in a programme for congenital cardiac surgery

In 1995, Miami Children's Hospital recognized an institutional problem with its programme providing surgical treatment for congenital cardiac malformations. There was a high rate of mortality for neonatal surgery, and no patients had survived attempted first stage palliation for hypoplastic left heart syndrome. The hospital enlisted nationally recognized consultants in congenital cardiac surgery and cardiology to review the existing programme, and to make recommendations for improvement. Based on these recommendations, a new team was recruited. The recruits were a young attending surgeon, an interventional cardiologist, and a cardiac intensivist, attracted from recognized centers of excellence in Boston and Toronto.

Use of routine ventricular assist following the first stage Norwood procedure

Surgical treatment of hypoplastic left heart syndrome has generated substantial interest and attention amongst cardiac surgeons since the initial reports from Norwood and his colleagues in 1980.1,2 Initial efforts at most programmes were to create reproducible results, and mortality rates remained high at several institutions throughout the 1980s and 1990s. A recent multi-institutional review demonstrates that the hospital mortality still remains high in numerous centers at the current time.3 Nevertheless, several advances over recent years have led to improved outcomes, and in the best centers, hospital survival now approaches 90%. Survival in successful centers is claimed to relate to the ability of the team to help the patient balance the systemic and pulmonary flows of blood. This ability to balance flow has been enhanced, over recent years, by numerous contributions, including decreasing the size of shunt ordinarily used,4 the use of alpha blockade,5 the rapid deployment of extracorporeal membrane oxygenation,6–8 and various forms of ventilatory manipulation.

Effect of a selection and postoperative care protocol on survival of infants with hypoplastic left heart syndrome

BACKGROUND

We report the development and implementation of a program designed to assign patients preoperatively to either transplant or Norwood procedure based on a score derived from known risk factors and to enhance postoperative care of infants undergoing the Norwood procedure.

METHODS

A weighted score for each of six variables comprised the scoring system: ventricular function, tricuspid regurgitation, ascending aortic diameter, atrial septal defect blood flow characteristics, blood type, and age. The scoring system was used to prospectively assign mortality risk and lead to recommendation of either Norwood procedure or transplantation.

RESULTS

Survival following the Norwood procedure significantly improved after the management program was implemented (88% versus 40% at 48 hours, 57% versus 10% at 30 days, and 50% versus 10% at 1 year, p < 0.0001 at each time point). The survival of the group that received a score of 7 or less (high risk) who underwent the Norwood procedure was 78% at 48 hours, 44% at 30 days, and 33% at 1 year; survival rates among patients considered lower risk (greater than 7) were 100% at 48 hours and 80% at 30 days and 1 year. Transplant outcomes remained unchanged.

CONCLUSIONS

We report improved survival following the Norwood procedure after the implementation of an institutional management approach aimed at improving the outcome of infants with hypoplastic left heart syndrome and may help neutralize historical biases toward Norwood procedure or transplantation.

Neonatal hemodynamics in patients with hypoplastic left heart syndrome

The neonate with hypoplastic left heart syndrome presents a challenge for clinical diagnosis and management. Three diagnostic goals must be met. First, it is necessary to make an etiologic cardiac diagnosis so as to rule out any genetic abnormality. Second, the anatomic cardiac diagnosis is made by segmental echocardiographic analysis, including details of the atrial arrangement, venous return, the patency of the arterial duct, atrial anatomy, and the arrangement of the aortic arch. Finally, the physiologic cardiac diagnosis is made by Doppler evaluation. In some patients, the diagnosis of hypoplastic left heart syndrome is not synonymous with functionally univentricular physiology, and a bi-ventricular repair can be achieved.1

Routine mechanical ventricular assist following the Norwood procedure—improved neurologic outcome and excellent hospital survival

BACKGROUND

Although excellent survival following the Norwood procedure for palliation of hypoplastic left heart syndrome (HLHS) is being achieved by some, most centers, especially the ones with small surgical volume and limited experience, continue to struggle with initial results. Survivors often showed evidence of significant neurologic injury. The early postoperative care is labor-intensive as attempts are made to balance the systemic and pulmonary circulation for these infants. We report our experience with routine use of mechanical circulatory assist to support the increased cardiac output requirements present following Norwood procedure.

METHODS

Eighteen consecutive infants undergoing Norwood operation for HLHS (Oregon Health & Science University [OHSU] 13; University of Louisville [UL] 5) were placed on a ventricular assist device (VAD) immediately following modified ultrafiltration in the operating room using the cardiopulmonary bypass (CPB) cannulas that were in the right atrium and the neoaorta. VAD flows were maintained at approximately 200 mL x kg(-1) x min(-1) and the patients were transported to the intensive care unit (ICU). Patients operated at OHSU also received neurodevelopmental testing before their Glenn procedure, approximately 4 to 6 months following their Norwood operation.

RESULTS

All patients were stable on VAD support and no attempt was made to balance the systemic and pulmonary circulation. The ventilator was manipulated to achieve systemic Pa0(2) between 30 and 45 mm Hg and PaC0(2) between 35 and 45 mm Hg. Evidence of hypoperfusion (increasing lactates) was managed by increasing the VAD flow. Lactates normalized [< 2 mmol/L]) by 1.8 +/- 1.1 days following surgery. Average time of VAD support was 3.1 +/- 1.0 (range, 2 to 5 days) and average time until chest closure was 3.4 +/- 1.5 (range, 2 to 8 days). There were two cases of postoperative bleeding (11.1%) requiring reexploration and one case of mediastinitis (5.5%) in a patient who has now gone on to successful Glenn. Sixteen of the eighteen patients survived (hospital survival mean 89% with a 95% confidence interval of 63.9% to 98.1%; 12/13 OHSU [92.3%]; 4/5 UL [80%]). Neurodevelopmental testing using the Mullen Scales of Early Learning and the Vineland Adaptive Behavior Scale were normal for all infants tested.

CONCLUSIONS

Routine postoperative use of VAD can support the increased cardiac output demands of infants following Norwood operation and results in a stable postoperative convalescence that does not require aggressive ventilator or inotrope manipulation. Although not a panacea, this strategy can simplify postoperative management, lead to excellent hospital survival, and possibly augment cerebral oxygen delivery, resulting in improved neurologic outcomes for this challenging group of patients.

Routine use of mechanical ventricular assist following the Norwood procedure

Conventional postoperative management after the Norwood procedure in patients with hypoplastic left heart syndrome suffers from three main shortfalls. First, the early postoperative care is often labor-intensive and ironically (despite sometimes heroic efforts), when babies die, health care providers often feel like failures, and in the worst scenarios, surgeons or other physicians create cultures of blame. Second, hospital survival is inconsistent in most centers, especially the ones with small surgical volume and limited experience. Third, survivors often show evidence of significant neurologic impairment. To address these postoperative problems, we have adopted the strategy of routinely placing all our patients with hypoplastic left heart syndrome on mechanical circulatory support immediately after their Norwood procedure. No attempt was made to balance the systemic and pulmonary circulation. Because an oxygenator was not used in the circuit, a much lower level of anticoagulation was used. Once the lactate level normalized, the amount of mechanical circulatory support was weaned. Since January of 2001, 23 patients have been managed using this strategy. The average time of mechanical circulatory support was approximately 3 days and has decreased to 2 days in more recent experience. The overall incidence of complications was 22%, and overall hospital survival was 87%. Neurodevelopmental testing before the Glenn procedure was normal for all patients tested. Routine postoperative use of mechanical ventricular assist device can support the increased cardiac output demands of infants following Norwood procedure and results in a stable postoperative convalescence. This strategy can simplify postoperative management, lead to excellent hospital survival, and possibly augment cerebral oxygen delivery resulting in improved neurologic outcomes for these patients.

The Southern Thoracic Surgical Association 50th anniversary celebration: the impact of STSA pediatric cardiothoracic surgery manuscripts on surgical practice

BACKGROUND

Members of the Southern Thoracic Surgical Association (STSA) have presented important pediatric cardiothoracic surgery papers at the annual meetings over the last 50 years. In order to determine the influence of these presentations on the practice of surgery, a review was undertaken. Early papers were characterized by emerging advances in open-heart surgery, anatomic congenital heart studies, and electrophysiologic discoveries that extended life with pacemakers. Later years were characterized by innovative myocardial preservation methods, improved cardiopulmonary bypass techniques, expanded homograft availability, emphasis on accurate repairs, intraoperative transesophageal echocardiography, and cardiopulmonary transplantation.

METHODS

All but one of the scientific programs of the annual meetings (that of 1964) were located. The programs were reviewed and 180 presentations were identified on topics in congenital heart disease, pediatric thoracic disease, and pediatric thoracic wall abnormalities. Of those 180 oral presentations, 155 manuscripts (86%) were eventually published or in press and available for critical review and analysis. Manuscripts were grouped by diagnosis or therapeutic intervention. We determined a "cumulative citation frequency" (CCF), which measures the number of times an article is cited in the bibliography of related papers in the universe of participating journals. The selected manuscripts were compared with the historic landmark contributions and the existing trends at the time, and the number of articles both by individual authors and from institutions were tallied.

RESULTS

Grouping by authors and institutions showed that 100 of 155 pediatric cardiothoracic manuscripts (65%) originated from 13 institutions. The CCF for the 20 leading articles ranged from 26 to 93.

CONCLUSIONS

This historical STSA 50-year record of pediatric cardiothoracic advances was accomplished in a milieu of collegial respect and camaraderie. Our annual meetings over the years have provided a venue for thoracic surgeons to share their ideas, innovations, and scientific inquiry. These contributions have significantly affected the practice of pediatric cardiothoracic surgery. The STSA has worked for 50 years and we trust that it will work for another 50 years and beyond.