Simulation analysis of interatrial transposition of venous return (Mustard’s operation)

Abstract

Transposition of the great arteries is functionally corrected by Mustard's operation, an operation in which the atrial septum is removed and the resulting common atrial chamber repartitioned by a baffle to transpose venous return to the heart. To better understand the new physiology, a physically-based mathematical model of the infant circulation following Mustard's operation was developed and studied with the aid of computer simulation. The model reproduces certain clinical observations, including the tendency for mean pressure in both atria to be equal early postoperatively and for the pressure waveform to exhibit a steep y-descent in the systemic venous atrium. Simulation studies suggest that the mechanism for the former is transbaffle pressure coupling resulting from dynamic motion of the baffle; the mechanism for the latter is limitation of the extent of such baffle excursions. Dynamic volume of the two atria is found in the model to change according to the relative performance of the two ventricles, and stiffening the baffle leads to pressure waveforms characteristic of a small, noncompliant atrium. Mechanisms for venous "obstruction" and decompression were also studied. The baffle and its movements, however, have little effect upon cardiac output in the model, leaving unexplained the clinical observation of low output early postoperatively.

Simulation of Apical and Atrio-aortic VAD in Patients with Transposition or Congenitally Corrected Transposition of the Great Arteries

“…In comparison to previously developed models on TGA (6, 7), the model described in this paper allows the simulation of both TGA and ccTGA and to personalize the physiopathological conditions according to specific patient hemodynamics. This personalization enables the model to be used not only to study the physiopathology, but also to support clinical decision-making by evaluating the changes in hemodynamic and circulatory parameters for a specific patient at pump implantation and at the follow-up, respectively.…”

“…Considering the lack of experience, the complex physiopathology, and the different surgical strate-gies adopted in infants or in adult life, the use of a numerical model could help to better understand the hemodynamics before and after a treatment and potentially support the clinical decision. Previously published models describe the TGA physiopathology and Mustard operation (atrial baffle) (6, 7). However, the existing models do not describe the interaction with VADs and are not personalized to patients.…”