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Quantification of flow through an interatrial communication. Application to the partial Fontan procedure
J M Pearl1, H Laks, S W Barthel
1Division of Cardiothoracic Surgery, University of California, Los Angeles.
The Journal of Thoracic and Cardiovascular Surgery
|December 1, 1992
Summary
Optimizing the partial Fontan procedure requires precise sizing of the atrial septal defect. This study developed guidelines for residual defect sizing, advocating for adjustable interatrial communications to improve patient outcomes.
Area of Science:
- Cardiovascular Surgery
- Pediatric Cardiology
- Hemodynamics
Background:
- The partial Fontan procedure is a vital option for high-risk patients, aiming to reduce venous pressure and enhance cardiac output.
- Accurate sizing of the residual atrial septal defect (ASD) is challenging due to patient variability and pressure gradients.
- Current methods may not adequately account for the complex interplay between defect size and pressure in optimizing flow dynamics.
Purpose of the Study:
- To establish evidence-based guidelines for sizing the residual defect in partial Fontan procedures.
- To investigate the relationship between pressure gradients, atrial septal defect size, and blood flow.
- To evaluate the accuracy of existing formulas (e.g., Gorlin formula) in predicting flow across ASDs.
Main Methods:
- Utilized a simulated model to analyze blood flow across various interatrial defect sizes under different pressure gradients.
- Employed porcine blood for experimental testing to mimic physiological conditions.
- Compared experimental flow data with predictions from the Gorlin formula.
Main Results:
- Demonstrated a linear correlation between flow and pressure gradient across all tested defect sizes.
- Identified a linear relationship between ASD size and blood flow at each specific pressure gradient.
- Found that the Gorlin formula overestimated flow by 10% to 40% compared to experimental data.
Conclusions:
- Precise control over residual defect size is critical, as minor variations significantly impact flow.
- Existing formulas may be inaccurate for predicting flow in the context of partial Fontan procedures.
- Advocates for the use of adjustable interatrial communications, such as snare-controlled devices, to optimize residual ASD sizing during partial Fontan surgery.