From the Guidelines
Hypoplastic left heart syndrome (HLHS) has a significantly improved prognosis with modern surgical interventions, with approximately 70-80% of children surviving to adulthood, as reported in the most recent study 1. Without treatment, HLHS is fatal within the first weeks of life. Treatment typically involves a three-stage surgical approach:
- the Norwood procedure performed within the first week of life,
- the Glenn procedure at 4-6 months, and
- the Fontan procedure at 2-4 years of age. Between surgeries, medications like digoxin, diuretics (furosemide 1-2 mg/kg/dose), ACE inhibitors (enalapril 0.1 mg/kg/day), and aspirin (3-5 mg/kg/day) are often prescribed to manage heart function and prevent complications, as mentioned in 1 and 1. Long-term survival requires lifelong cardiology follow-up as these patients face risks of heart failure, arrhythmias, protein-losing enteropathy, and neurodevelopmental delays. Factors affecting prognosis include timing of diagnosis (prenatal detection improves outcomes), presence of other congenital anomalies, surgical expertise at the treating center, and individual anatomical variations, as discussed in 1 and 1. Heart transplantation remains an alternative option for some patients, particularly those who develop complications after palliative surgeries, as noted in 1. It is essential to consider the unique aspects of Fontan circulation, which relies on elevated, nonpulsatile venous pressure to drive passive blood flow through the pulmonary vascular bed, leading to chronically elevated central venous pressure, decreased preload to the systemic ventricle, and impaired augmentation of cardiac output during periods of exercise or stress, as described in 1. Overall, the prognosis for HLHS patients has improved significantly, but ongoing care and monitoring are crucial to managing potential complications and improving quality of life, as emphasized in 1.
From the Research
Hypoplastic Left Heart Syndrome Prognosis
- Hypoplastic left heart syndrome is a rare congenital heart defect with a historically poor prognosis, but surgical management has improved outcomes 2.
- The condition requires several cardiac surgeries for survival, with each stage posing unique hemodynamic challenges 3.
- Surgical options include cardiac transplantation or staged palliation with the Norwood operation, followed by a two-staged Fontan procedure 4.
- The Norwood procedure has become a milestone in the effective palliation for neonates born with hypoplastic left heart syndrome, with improvements in outcome over time due to increased experience and expertise 5.
Surgical Outcomes
- Early mortality after the Norwood procedure has decreased significantly over time, from 39.06% to 0% in some studies 4.
- Factors influencing early mortality include lower operative weight, ascending aortic size, prolonged duration of cardiopulmonary bypass, and hypothermic circulatory arrest 4.
- The two-stage Fontan procedure has been shown to bear only a low risk and lead to good quality of life, with some studies reporting no mortality after the complete Fontan operation 6.
Long-Term Outcomes
- Careful multidisciplinary involvement in the care of patients with hypoplastic left heart syndrome is improving outcomes, but morbidity and mortality are still substantial 3.
- Affected children growing into adolescence and adulthood pose new problems and demands, requiring ongoing management and care 2.
- The longest follow-up after the complete Fontan operation has been reported as 6 years, with all children surviving and being completely palliated 6.