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J Thorac Cardiovasc Surg. 2010 Sep;140(3):529-36. doi: 10.1016/j.jtcvs.2010.04.037. Epub 2010 Jun 18.

Cavopulmonary assist for the univentricular Fontan circulation: von Kármán viscous impeller pump.

Author information

1
Section of Cardiothoracic Surgery, Department of Surgery, Indiana University School of Medicine and James Whitcomb Riley Hospital for Children, Indianapolis, Ind 46202, USA. rodefeld@iupui.edu

Abstract

OBJECTIVE:

In a univentricular Fontan circulation, modest augmentation of existing cavopulmonary pressure head (2-5 mm Hg) would reduce systemic venous pressure, increase ventricular filling, and thus substantially improve circulatory status. An ideal means of providing mechanical cavopulmonary support does not exist. We hypothesized that a viscous impeller pump, based on the von Kármán viscous pump principle, is optimal for this role.

METHODS:

A 3-dimensional computational model of the total cavopulmonary connection was created. The impeller was represented as a smooth 2-sided conical actuator disk with rotation in the vena caval axis. Flow was modeled under 3 conditions: (1) passive flow with no disc; (2) passive flow with a nonrotating disk, and (3) induced flow with disc rotation (0-5K rpm). Flow patterns and hydraulic performance were examined for each case. Hydraulic performance for a vaned impeller was assessed by measuring pressure increase and induced flow over 0 to 7K rpm in a laboratory mock loop.

RESULTS:

A nonrotating actuator disc stabilized cavopulmonary flow, reducing power loss by 88%. Disk rotation (from baseline dynamic flow of 4.4 L/min) resulted in a pressure increase of 0.03 mm Hg. A further increase in pressure of 5 to 20 mm Hg and 0 to 5 L/min flow was obtained with a vaned impeller at 0 to 7K rpm in a laboratory mock loop.

CONCLUSIONS:

A single viscous impeller pump stabilizes and augments cavopulmonary flow in 4 directions, in the desired pressure range, without venous pathway obstruction. A viscous impeller pump applies to the existing staged protocol as a temporary bridge-to-recovery or -transplant in established univentricular Fontan circulations and may enable compressed palliation of single ventricle without the need for intermediary surgical staging or use of a systemic-to-pulmonary arterial shunt.

PMID:
20561640
PMCID:
PMC2924921
DOI:
10.1016/j.jtcvs.2010.04.037
[Indexed for MEDLINE]
Free PMC Article
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