Right Ventricular Morphology Is Associated With Mortality at All Stages of Single Ventricle Palliation

The impact of dominant ventricle morphology and additional ventricular chamber size on clinical outcomes in patients with Fontan circulation

OBJECTIVES

The functional roles of ventricular dominance and additional ventricular chamber after Fontan operation are still uncertain. We aim to assess and correlate such anatomical features to late clinical outcomes.

METHODS

Fontan patients undergoing cardiac MRI and cardiopulmonary exercise test between January 2020 and December 2022 were retrospectively reviewed. Clinical, cardiac MRI, and cardiopulmonary exercise test data from the last follow-up were analysed.

RESULTS

Fifty patients were analysed: left dominance was present in 29 patients (58%, median age 20 years, interquartile range:16-26). At a median follow-up after the Fontan operation was 16 years (interquartile range: 4-42), NYHA classes III and IV was present in 3 patients (6%), 4 (8%) underwent Fontan conversion, 2 (4%) were listed for heart transplantation, and 2 (4%) died. Statistical analysis showed that the additional ventricular chamber was larger (>20 mL/m2) in patients with a right dominant ventricle (p = 0.01), and right dominance was associated with a higher incidence of post-operative low-cardiac output syndrome (p = 0.043). Left ventricular dominance was associated with a better ejection fraction (p = 0.04), less extent of late gadolinium enhancement (p = 0.022), higher metabolic equivalents (p = 0.01), and higher peak oxygen consumption (p = 0.033). A larger additional ventricular chamber was associated with a higher need for post-operative extracorporeal membrane oxygenation support (p = 0.007), but it did not influence functional parameters on cardiac MRI or cardiopulmonary exercise test.

CONCLUSIONS

In Fontan patients, left ventricular dominance correlated to better functional outcomes. Conversely, a larger additional ventricular chamber is more frequent in right ventricular dominance and can negatively affect the early post-Fontan course.

Long-Term Survival After Single-Ventricle Palliation: A Swedish Nationwide Cohort Study

BACKGROUND

Long-term survival after single-ventricle palliation and the effect of dominant ventricle morphology in large, unselected series of patients are scarcely reported.

METHODS AND RESULTS

This nationwide cohort study included all children undergoing operation with single-ventricle palliation during their first year of life in Sweden between January 1994 and December 2019. Data were obtained from institutional records and assessment of underlying cardiac anomaly and dominant ventricular morphology was based on complete review of medical records, surgical reports, and echocardiographic examinations. Data on vital status and date of death were retrieved from the Swedish Cause of Death Register, allowing for complete data on survival. Among 766 included patients, 333 patients (43.5%) were classified as having left or biventricular dominance, and 432 patients (56.4%) as having right ventricular (RV) dominance (of whom 231 patients had hypoplastic left heart syndrome). Follow-up was 98.7% complete (10 patients emigrated). Mean follow-up was 11.3 years (maximum, 26.7 years). Long-term survival was significantly higher in patients with left ventricular compared with RV dominance (10-year survival: 91.0% [95% CI, 87.3%-93.6%] versus 71.1% [95% CI, 66.4%-75.2%]). RV dominance had a significant impact on outcomes after first-stage palliation but was also associated with impaired survival after completed total cavopulmonary connection. In total, 34 (4.4%) patients underwent heart transplantation. Of these 34 patients, 25 (73.5%) had predominant RV morphology.

CONCLUSIONS

This study provides clinically relevant knowledge about the long-term prognosis in patients with different underlying cardiac anomalies undergoing single-ventricle palliation. RV dominance had a significant impact on outcomes after initial surgical treatment but was also associated with impaired survival after completed Fontan circulation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03356574.

What have we learnt 50 years after the first Fontan procedure?

The Fontan procedure is often the only definitive palliative surgical option for patients with a variety of complex CHD sharing in common, a single, dominant ventricle. In recent decades, imaging and therapeutic improvement have played a crucial role in those patients in whom many complications can hamper their life. After 50 years from the first procedure, heart transplantation remains the only definitive treatment for those with a failing Fontan circulation.