Fontan haemodynamics in adults with obesity compared with overweight and normal body mass index: a retrospective invasive exercise study - Report - MDSpire
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Fontan haemodynamics in adults with obesity compared with overweight and normal body mass index: a retrospective invasive exercise study
Haemodynamic Impact of Obesity in Adults Post-Fontan During Exercise
Overview
In adults post-Fontan, obesity is associated with worse aerobic capacity, increased cardiac output, elevated filling pressures, and reduced arterial oxygen saturation both at rest and during exercise. These haemodynamic alterations resemble those seen in the obesity phenotype of heart failure with preserved ejection fraction.
Background
Obesity prevalence is rising globally and affects adults with repaired congenital heart disease, including those post-Fontan. While many Fontan patients are underweight in childhood, nearly 40% of adults post-Fontan are overweight or obese, paralleling general population trends. Obesity in biventricular hearts is known to increase cardiac output and filling pressures, but its effects on Fontan physiology, characterized by passive venous return and low cardiac index, remain poorly understood. This study aimed to clarify the impact of obesity on invasive haemodynamics and exercise capacity in this population.
Data Highlights
Parameter
Obesity (BMI >30)
Overweight/Normal BMI (≤30)
P-value
Number of patients
18
59
BMI (kg/m2)
36.4 ± 3
24.1 ± 3.6
Peak VO2 (mL/kg/min)
15.6 ± 3.5
19.6 ± 5.8
0.04
Resting Systemic Flow (Qs, L/min)
7.0 (4.8; 8.3)
4.8 (3.9; 5.8)
0.001
Resting Pulmonary Artery Pressure (mmHg)
16.3 ± 3.5
13.1 ± 3.5
0.002
Resting PA Wedge Pressure (mmHg)
11.7 ± 4.4
8.9 ± 3.1
0.01
Resting Arterial O2 Saturation (%)
89.5 (86.5; 92.3)
93 (90; 95)
Exercise PA Pressure (mmHg)
29.7 ± 6.5
24.7 ± 6.8
0.01
Exercise PA Wedge Pressure (mmHg)
23.0 ± 6.5
19.8 ± 7.3
0.047
Exercise Arterial O2 Saturation (%)
82.4 ± 7.0
89 (85; 92)
0.003
Key Findings
Adults post-Fontan with obesity had significantly lower peak oxygen consumption compared to those with overweight/normal BMI (15.6 vs. 19.6 mL/kg/min, P=0.04).
Resting systemic flow was higher in obese patients (7.0 vs. 4.8 L/min, P=0.001), indicating increased cardiac output.
Both resting and exercise pulmonary artery pressures and wedge pressures were elevated in the obesity group, suggesting higher filling pressures.
Arterial oxygen saturation was lower at rest and during exercise in obese patients, reflecting impaired oxygen delivery.
The haemodynamic profile in obese Fontan patients parallels the obesity phenotype seen in heart failure with preserved ejection fraction.
Clinical Implications
Clinicians should recognize that obesity in adults post-Fontan is associated with adverse haemodynamic changes and reduced exercise capacity, which may contribute to clinical deterioration. Addressing obesity and its cardiometabolic consequences could potentially improve haemodynamics and outcomes, although further prospective studies are needed to confirm therapeutic benefits.
Conclusion
Obesity in adults post-Fontan is linked to worsened aerobic capacity and unfavorable haemodynamics at rest and during exercise, mirroring patterns seen in heart failure with preserved ejection fraction. Targeted interventions to manage obesity in this population warrant further investigation.
by Derek N Opp, C Charles Jain, Alexander C Egbe, Barry A Borlaug, Yogesh V Reddy, Heidi M Connolly, Kyla M Lara-Breitinger, Rachael Cordina, William R Miranda
