Atrial Function and the Pressure–Strain Relationship in Patients with Fontan Circulation

Q: What are the key findings of this study?

Patients with Fontan circulation showed significantly lower reservoir and conduit strains than controls, but the atrial pressure-strain index did not differ significantly (0.20 vs. 0.20, P=0.417).

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Fontan circulation (n=26). Intervention: Fontan circulation vs. Biventricular circulation with normal cardiac function. Primary outcome: Atrial pressure-strain index (p=0.417).

Q: What does this research mean for the field?

Patients with Fontan circulation have significantly lower atrial reservoir and conduit strains than controls, but their atrial pressure–strain index does not significantly differ or correlate with conventional hemodynamic parameters. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Hideharu Oka; Yuki Shibagaki; Keita Ito; Kouichi Nakau; Satoru Takahashi

doi:10.2463/mrms.mp.2026-0126

January 1, 2026Magnetic Resonance in Medical SciencesOpen Access

Atrial Function and the Pressure–Strain Relationship in Patients with Fontan Circulation

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Key result

Fontan circulation is linked to lower atrial strain but shows no difference in pressure-strain index.

P=0.417
n=26

Why the study?

Atrial function is associated with exercise tolerance and survival in patients with Fontan circulation, but the atrial pressure-strain relationship has not been well studied.

Does Fontan circulation alter the atrial pressure-strain relationship and atrial strain parameters compared to controls with biventricular circulation?

Key Points

To investigate atrial function and the atrial pressure–strain relationship in patients with Fontan circulation using cardiac MRI and catheterization data compared with controls.
Retrospectively analyzed 16 Fontan patients (median age: 12.0 years) who had cardiac MRI between 2020 and 2026, alongside 10 control patients (median age: 8.5 years).
Measured atrial strain from 4-chamber cine MRI images and calculated the pressure–strain index using pulmonary artery wedge pressure (PAWP) waveforms as a surrogate for atrial pressure.
Reservoir strain (16.7% vs. 26.2%, P < 0.001) and conduit strain (6.2% vs. 18.7%, P < 0.001) were significantly lower in Fontan patients than controls, whereas pump strain did not differ (9.4% vs. 8.5%, P = 1.000).
The pressure–strain index was not significantly different between Fontan patients and controls (0.20 vs. 0.20, P = 0.417) and showed no significant correlation with conventional hemodynamic parameters.
Fontan patients had a significantly smaller PAWP v–x difference (3.3 vs. 5.0 mmHg, P = 0.009), higher central venous pressure (11.5 vs. 4.0 mmHg, P < 0.001), and lower cardiac index (2.9 vs. 3.8 L/min/m2, P = 0.007).

Study Design

Type

Observational (n=26)

Multicenter

No

Structured PICO

Does Fontan circulation alter the atrial pressure-strain relationship and atrial strain parameters compared to controls with biventricular circulation?

P

Population

26 children and adolescents (16 with Fontan circulation and 10 controls with normal biventricular function) evaluated via cardiac MRI and catheterization to assess atrial mechanics.

E

Exposure

Observation of Fontan circulation physiology using cardiac MRI feature-tracking for atrial strain and cardiac catheterization for pulmonary artery wedge pressure (PAWP)

C

Comparator

Control patients with biventricular circulation (history of Kawasaki disease with no abnormalities in cardiac function) undergoing similar cardiac MRI and catheterization assessments

O

Outcome

Atrial strain values (reservoir, conduit, and pump strain) and the pressure-strain index (calculated as the PAWP v-x difference divided by reservoir strain)surrogate

Main Result

Absolute Event Rate: 0.2% vs 0.2%

p-value: p=0.417

While atrial reservoir and conduit strains are significantly reduced in patients with Fontan circulation, the pressure-strain index does not significantly differ from controls, casting doubt on the physiological significance of the atrial pressure-strain relationship in this unique hemodynamic setting.

Limitations

Single-center study with a small sample size, limiting statistical power.
The feature-tracking method is influenced by image quality and analysis software, and may be affected by complex atrial anatomy.
PAWP v-x difference has not been validated as a surrogate for atrial pressure change in the Fontan population.
The control group consisted of patients with Kawasaki disease rather than completely healthy individuals.
Atrial late gadolinium enhancement (LGE) was assessed visually without dedicated dark-blood LGE imaging.
Single-center study with a small number of patients (risk of type II error).
Feature-tracking method is influenced by image quality, analysis software, and complex atrial anatomy.
PAWP v-x difference is influenced by loading conditions and has not been validated as a surrogate for atrial pressure change in this population.
Kawasaki disease control group may differ from healthy individuals.
Lack of dedicated dark-blood LGE imaging for definitive atrial fibrosis assessment.

Implication

Impaired Fontan atrial strains should not yet guide management; leaves open whether pressure-strain index refines risk stratification beyond strain alone.

Abstract

PURPOSE: Atrial function is associated with exercise tolerance and survival in patients with Fontan circulation. Although atrial function is often evaluated using strain parameters, changes in atrial pressure are also important but have not been well studied. This study aimed to investigate the atrial pressure-strain relationship in patients with Fontan circulation using data from cardiac catheterization and MRI. METHODS: We retrospectively included 16 patients (median age: 12 years) who underwent cardiac MRI between 2020 and 2026, and 10 control patients (median age: 8.5 years). Atrial strain values were evaluated from 4-chamber cine MRI images. Pulmonary artery wedge pressure waveforms were used as a surrogate for atrial pressure. The pressure-strain index was calculated as an integrated measure of atrial pressure and strain. RESULTS: , P = 0.007). Reservoir and conduit strains were lower in the Fontan group (reservoir strain: 16.7 vs. 26.2%, P < 0.001; conduit strain: 6.2 vs. 18.7%, P < 0.001); however, no significant difference was observed in pump strain between the groups. No significant difference was also noted in pressure-strain index between the 2 groups (0.2 vs. 0.2, P = 0.417). CONCLUSION: In patients with Fontan physiology, reservoir and conduit strain were lower than in controls. In contrast, atrial pressure-strain relationship was not clearly associated with conventional Fontan hemodynamic parameters. These findings suggest that the physiological significance of atrial pressure-strain relationship in the Fontan circulation remains uncertain.

Discussion

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Cite This Study

Oka et al. (2026) conducted an observational in Fontan circulation (n=26). Fontan circulation vs. Biventricular circulation with normal cardiac function was evaluated on Atrial pressure-strain index (p=0.417). Patients with Fontan circulation showed significantly lower reservoir and conduit strains than controls, but the atrial pressure-strain index did not differ significantly (0.20 vs. 0.20, P=0.417).

synapsesocial.com/papers/6ad0fcf33afa093ea9ad0107 https://doi.org/10.2463/mrms.mp.2026-0126

Topics

Cardiac MRI

Congenital heart disease adults

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Atrial Function and the Pressure–Strain Relationship in Patients with Fontan Circulation

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Topics

Atrial Function and the Pressure–Strain Relationship in Patients with Fontan Circulation

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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