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Assessment of Diastolic Function in Single-Ventricle Patients After the Fontan Procedure
Renee Margossian1, Lynn A Sleeper2, Gail D Pearson3
1Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.
Insights
Diastolic function grade (DFG) was assessed in pediatric patients after the Fontan procedure. Abnormal DFG was common but showed few associations with clinical status, suggesting current methods may not apply to this population.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Cardiac Physiology
Background:
- Patients with functional single ventricles post-Fontan procedure exhibit abnormal cardiac mechanics.
- Understanding factors influencing diastolic function is crucial for managing these complex patients.
Purpose of the Study:
- To identify factors affecting diastolic function in Fontan patients.
- To explore associations between diastolic function and current clinical status.
Main Methods:
- Echocardiograms were analyzed from the Pediatric Heart Network Fontan Cross-Sectional Study.
- Diastolic function grade (DFG) was categorized (normal, impaired relaxation, pseudonormalization, restrictive).
- Relationships between DFG, pre-Fontan variables, and current clinical status were examined.
Main Results:
- Diastolic function grade (DFG) was assessable in 60% of patients (mean age 11.7 years).
- 32% had normal DFG, while 60% had impaired relaxation, pseudonormalization, or restrictive patterns.
- DFG was linked to exercise performance, with most patients not achieving maximal effort having DFG 2 or 3.
Conclusions:
- Current diastolic function assessment algorithms identify many Fontan patients with abnormal DFG.
- Few significant clinical associations were found, potentially indicating limited impact or methodological limitations in this population.
Background:
Patients with functional single ventricles after the Fontan procedure have abnormal cardiac mechanics. The aims of this study were to determine factors that influence diastolic function and to describe associations of diastolic function with current clinical status.
Methods:
Echocardiograms were obtained as part of the Pediatric Heart Network Fontan Cross-Sectional Study. Diastolic function grade (DFG) was assessed as normal (grade 0), impaired relaxation (grade 1), pseudonymization (grade 2), or restrictive (grade 3). Studies were also classified dichotomously (restrictive pattern present or absent). Relationships between DFG and pre-Fontan variables (e.g., ventricular morphology, age at Fontan, history of volume-unloading surgery) and current status (e.g., systolic function, valvar regurgitation, exercise performance) were explored.
Results:
DFG was calculable in 326 of 546 subjects (60%) (mean age, 11.7 ± 3.3 years). Overall, 32% of patients had grade 0, 9% grade 1, 37% grade 2, and 22% grade 3 diastolic function. Although there was no association between ventricular morphology and DFG, there was an association between ventricular morphology and E', which was lowest in those with right ventricular morphology (P < .001); this association remained significant when using Z scores adjusted for age (P < .001). DFG was associated with achieving maximal effort on exercise testing (P = .004); the majority (64%) of those not achieving maximal effort had DFG 2 or 3. No additional significant associations of DFG with laboratory or clinical measures were identified.
Conclusions:
Assessment of diastolic function by current algorithms results in a high percentage of patients with abnormal DFG, but few clinically or statistically significant associations were found. This may imply a lack of impact of abnormal diastolic function on clinical outcomes in this cohort, or it may indicate that the methodology may not be applicable to pediatric patients with functional single ventricles.
