Two slits good, four slits bad? Assessing the hemodynamic impact of modifications to microvascular plugs in pulmonary flow restriction using a bench-top model.

Authors

Natalie Soszyn, Sungho Park, Catalina Vargas Acevedo, Ernesto Mejia, Alex Barker, Jenny Zablah, Gareth Morgan

Published in

Cardiology in the young. Pages 1-6. Sep 24, 2026. Epub Sep 24, 2026.

Abstract

In patients with functionally univentricular circulations, the flow restriction achieved by modifying microvascular plugs (MVPs) during percutaneous stage I palliation has not been widely quantified. This study evaluates how progressive modification of the polytetrafuoroethylene (PTFE) membrane of MVPs alters flow restriction using a bench-top model of uni-ventricular physiology.
A 3D-printed model mimicking branch pulmonary arteries in parallel with a systemic outflow was connected to a Harvard pulsatile pump. Two MVP-9Q devices, each modified with one, two, three, or four slits in the PTFE membrane, were placed in limbs representing left and right pulmonary arteries. Mathematical scaling produced a valid hemodynamic model matching neonatal univentricuar physiology. Flow (L/min) was measured using sensors placed on both pulmonary arteries and the systemic limb. Flow distribution between systemic and pulmonary limbs was calculated as a percentage of fixed total flow to determine the pulmonary (Qp) to systemic (Qs) flow ratio (Qp:Qs).
With a baseline model representing 2:1 Qp:Qs ratio, MVPs with one slit reduced pulmonary flow (Qp) by 23%. Two slits reduced Qp by 21% and produced a Qp:Qs ratio closest to 1:1. Additional slits progressively increased Qp and reduced restriction (three-slits: 18% reduction, Qp:Qs 1.1:1; four-slits: 15% reduction, Qp:Qs 1.3:1).
Incremental PTFE membrane modification generated proportional but nonlinear effects on flow distribution in a simulated univentricular circulation. Creating one or two slits provided the optimal balance between pulmonary and systemic flow, while more than two slits produced minimal restriction.

PMID:
42779288
Bibliographic data and abstract were imported from PubMed on 24 Sep 2026.

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