Hybrid procedures in the management of hypoplastic left heart syndrome: a systematic review.

Neonates with hypoplastic left heart syndrome (HLHS) are at risk of high mortality and neurodevelopmental morbidity. As an alternative to Norwood-type stage I palliation, the hybrid procedure has been developed. It consists of bilateral pulmonary artery banding, catheter-based stenting of the arterial duct and balloon atrioseptostomy and delays open-heart surgery. Thus, it may be associated with a better outcome. The aim of this study was to determine the mortality and neurodevelopmental outcome in patients with HLHS and other univentricular heart (UVH) defects treated with hybrid or Norwood procedures. Thirty-one children (18 males) with HLHS and other UVH defects undergoing Norwood or hybrid procedure between 2004 and 2008 were consecutively enrolled. Mortality and neurodevelopmental outcome at 1 year of age were determined. One-year mortality was 36% (31% in the hybrid vs. 39% in the Norwood group, P=0.71). Predictors of mortality were lower birth weight (P=0.02), older age at first procedure (P=0.02) and smaller size of ascending aorta (P=0.05). Overall, median psychomotor development index (PDI) and mental development index (MDI) of the Bayley Scales of Infant Development II were lower than the norm of 100 [PDI 57 (49-99), P<0.001; MDI 91 (65-109), P=0.002]. No effect of surgical treatment on neurodevelopmental outcome was found. Predictors of impaired motor outcome were length of hospital stay (LOHS) (P=0.01), lower body weight at second procedure (P=0.004) and female sex (P=0.01). Predictors of impaired cognitive outcome were longer mechanical ventilation time (P=0.03), intensive care unit stay (P=0.04) and LOHS (P<0.001), respectively. Mortality at 1 year of age is comparable between patients undergoing hybrid and Norwood procedures. Early neurodevelopmental outcome is significantly impaired in patients with both HLHS and other UVH defects. Multicentre randomized studies are needed to determine the long-term neurodevelopmental outcome of children treated with the hybrid procedure.

Infants with hypoplastic left heart syndrome (HLHS) are at risk for interstage morbidity and mortality, especially between the first and second surgical stages after the Norwood and hybrid procedures. This study compared the morbidity and mortality of patients treated by either the Norwood or the hybrid procedure for HLHS between the first and second stages who were undergoing interstage monitoring. Between October 2008 and December 2011, 26 infants (14 boys) with HLHS (n = 16) and other univentricular heart malformations with aortic arch anomaly (n = 10) were scheduled for interstage monitoring after Norwood I (n = 12) and hybrid (n = 14) procedures. Three infants (11.5 %) died after first-stage palliation (one hybrid patient and two Norwood patients), and three infants (11.5 %) died after second-stage palliation (two hybrid patients and one Norwood patient) (p = 0.83), all after early second-stage surgery (<90 days). The Norwood I and hybrid procedures did not differ in terms of overall mortality (23 %) (three hybrid and three Norwood patients; p = 1.00). Seven infants (26.9 %) could not be discharged from the hospital due to hemodynamic instability and were referred for early second-stage surgery (<90 days). After the first stage, the invasive reevaluation rate before discharge was high (53.8 %), with cardiac catheterizations for 8 of 14 patients after the hybrid procedure and for 6 of 12 patients after the Norwood procedure (p = 0.69). A total of 11 reinterventions were performed (eight by catheter and three by surgery). Of the eight catheter reinterventions, five were performed for hybrid patients (p = 0.22). For 14 infants, 89 days (range 10-177 days) of interstage monitoring were scheduled. One infant (3.9 %) died during the interstage monitoring. The findings showed a breach of the physiologic criteria for interstage monitoring in seven infants (50 %) after 10 days (range 4-68 days) (five hybrid and two Norwood patients), leading to rehospitalization and catheterization for six patients (four hybrid and two Norwood patients), requiring interventions for two patients (patent arterial duct stent dilation, and atrial septal defect stenting, all for hybrid patients). Overall, three of the seven patients with red flag events of interstage monitoring were candidates for early second-stage surgery. In conclusion, morbidity among infants treated for HLHS remains high, either before or after hospital discharge, emphasizing the need of interstage monitoring programs. Despite retrograde aortic flow in infants with HLHS after the hybrid procedure, the mortality rate was comparable between the two groups. Mortality occurs after early second-stage surgery (<90 days).

Patients with hypoplastic left heart syndrome (HLHS) undergoing staged palliation until Fontan procedure are at risk for impaired neurodevelopmental (ND) outcome. The Hybrid procedure with bilateral pulmonary artery banding, ductal stenting, and balloon atrioseptostomy may offer a less invasive stage I procedure compared to the Norwood stage I procedure avoiding early neonatal cardiopulmonary bypass (CPB) surgery. Despite altered fetal cerebral hemodynamics, the type of stage I procedure may be a covariate influencing ND outcome and functional outcome may also be altered due to postponing neonatal CPB surgery. Within this review, we analyzed ND outcome as well as functional outcome after Hybrid procedure as stage I procedure. The review analyzed original publications (OPs) published before March 15, 2022, identified by Cochrane, EMBASE, OVID, Scopus, and Web of science. An OP was included if short-to-long-term neurodevelopment outcome, brain development, somatic, and cardiac outcome in patients for HLHS and variants treated by Hybrid procedure were analyzed. In addition to database searches, we reviewed all references of the analyzed OP to obtain a comprehensive list of available studies. The author, year of publication, demographic characteristics of study population, study design (prospective or retrospective), study assessment, and main findings were summarized. Twenty-one OPs were included with data of patients with ND outcome and functional cardiac outcome. Overall, there is an impaired mid-term ND outcome in patients with Hybrid procedure as stage I for HLHS. Only slight differences between stage I procedures (Hybrid vs. Norwood) in two comparing studies have been determined affecting right ventricular remodeling, short- and mid-term ND outcome, reduced brain growth until two years of age, sufficient quality of life, and altered hemodynamics influencing brain volumes and cerebral perfusion pattern. Despite some minor differences regarding the mid-term follow-up in patients with HLHS comparing Hybrid vs. Norwood procedure, its impact on ND outcome seems rather low. This may be explained by the large number of covariates as well as the small study populations and the different selection criteria for patients undergoing Hybrid or Norwood procedure as stage I.

Apples to oranges: Making sense of hybrid palliation for hypoplastic left heart syndrome

ObjectiveThe ‘hybrid procedure’, consisting of surgical banding of the pulmonary arteries with intraoperative stenting of the arterial duct, was developed as primary palliation in hypoplastic left heart syndrome (HLHS), avoiding...

Commentary: The right procedure for the right patient

Smaller brain volumes at two years of age in patients with hypoplastic left heart syndrome - Impact of surgical approach

The primary objectives were to examine utilization of the Hybrid versus the Norwood procedure for patients with hypoplastic left heart syndrome or variants and the impact on hospital mortality. The Hybrid procedure was 1st used at our institution in 2004. Review of all subjects undergoing the Norwood or Hybrid procedure between 1 January 1984 and 31 December 2022. The study period was divided into 8 eras: era 1, 1984-1988; era 2, 1989-1993; era 3, 1994-1998; era 4, 1999-2003; era 5, 2004-2008; era 6, 2009-2014; era 7, 2015-2018 and era 8, 2019-2022. The primary outcome was in-hospital mortality. Mortality rates were computed using standard binomial proportions with 95% confidence intervals. Rates across eras were compared using an ordered logistic regression model with and adjusted using the Tukey-Kramer post-hoc procedure for multiple comparisons. In the risk-modelling phase, logistic regression models were specified and tested. The Norwood procedure was performed in 1899 subjects, and the Hybrid procedure in 82 subjects. Use of the Hybrid procedure increased in each subsequent era, reaching 30% of subjects in era 8. After adjustment for multiple risk factors, use of the Hybrid procedure was significantly and positively associated with hospital mortality. Despite the increasing use of the Hybrid procedure, overall mortality for the entire cohort has plateaued. After adjustment for risk factors, use of the Hybrid procedure was significantly and positively associated with mortality compared to the Norwood procedure.

The Modified Norwood Procedure at Necker Hospital: Stage I and II for Hypoplastic Left Heart Syndrome

The hybrid strategy is an alternative to the traditional Norwood procedure for initial palliation of infants with hypoplastic left heart syndrome (HLHS) who are deemed to be at high surgical risk. Numerous single-center studies have compared the two procedures, showing similar early outcomes, although the cohort sizes are likely insufficiently powered to detect significant differences. The current meta-analysis aims to explore the early morbidity and mortality associated with the hybrid compared to the Norwood procedure. MEDLINE, Cochrane Libraries, and Embase were systematically searched, and 14 studies were included for statistical synthesis, comprising 263 hybrid and 426 Norwood patients. Early mortality was significantly higher in the hybrid patients (relative risk [RR] = 1.54, P < .05, 95% confidence interval [CI]: 1.02-2.34), whereas interstage mortality was comparable between the two groups (RR = 0.88, P > .05, 95% CI: 0.46-1.70). Six-month (RR = 0.89, P < .05, 95% CI: 0.80-1.00) and one-year (RR = 0.88, P < .05, 95% CI: 0.78-1.00) transplant-free survival was also inferior among the hybrid patients. Furthermore, the hybrid patients required more reinterventions following initial surgical palliation (RR = 1.48, P < .05, 95% CI: 1.09-2.01), although the two groups had comparable length of hospital and intensive care unit stay postoperatively. In conclusion, our results suggest that the hybrid procedure is associated with worse early survival compared to the traditional Norwood when used for initial palliation of infants with HLHS. However, due to the hybrid being used preferentially for high-risk patients, definitive conclusions regarding the efficacy of the procedure cannot be drawn.

After completing this article, readers should be able to: 1. Describe the developments that have allowed advances in neonatal cardiac surgery. 2. Describe the diagnostic approach to hypoplastic left heart syndrome (HLHS). 3. Delineate the preoperative management of the neonate who has HLHS. 4. Describe the original Norwood procedure and subsequent modifications. 5. Delineate the optimal therapy in the postoperative period for neonates who have a single ventricle. Advances in the surgical and medical management of children who have congenital heart disease (CHD) have led to a dramatic improvement in overall survival and reduced the long-term sequelae of open-heart surgery. With improved survival and decreased morbidity over the past 2 decades, the early complete repair of complex congenital heart problems in preterm and low-birthweight neonates has gained wider acceptance. Cardiologists and cardiothoracic surgeons now consider and perform complete neonatal repair more frequently than palliative surgery in this patient population. The treatment of hypoplastic left heart syndrome (HLHS) best illustrates the evolution of management strategies to improve survival and long-term outcome. A recent modification of the Norwood operation that involves a right ventricle-to-pulmonary artery conduit has led to much improved early postoperative stability and, in many centers, improved survival to a stage II superior cavopulmonary connection. A multidisciplinary team approach is required to provide the necessary care for this complex patient population. In 1938, Robert Gross at Children’s Hospital in Boston successfully ligated a patent ductus arteriosus, and this procedure—performed against the wishes of surgeon-in-chief William Ladd—opened the era of surgery for CHD. (1) Gross and Hufnagel performed detailed animal experiments to develop a technique for treatment of coarctation of the aorta that involves excision and end-to-end anastomosis. (2) Clarence Craaford of Stockholm, Sweden, had visited Gross to observe his experimental work, and in October 1944, Craaford and Nylin were the first to repair aortic …

IntroductionThe hybrid procedure (HP) is an alternative first step palliation in children with hypoplastic left heart syndrome (HLHS). Following the HP, patients undergo one of two pathways: ‘three-stage’ - the...

Invited Commentary

Hybrid Procedure for Neonates With Hypoplastic Left Heart Syndrome at High-Risk for Norwood: Midterm Outcomes

Stage 1 hybrid palliation for hypoplastic left heart syndrome—assessment of contemporary patterns of use: An analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database