Staged surgical palliation and ventricular performance in functionally single ventricle anatomy

This thesis reports a series of laboratory and clinical studies designed to investigate the acute effect of surgical palliation on ventricular function in children with functionally single ventricle anatomy. Ventricular volume and pressure were measured using a combined pressure-conductance catheter. Initial laboratory-based experiments were performed using a physical model of the left ventricle, which allowed examination of the measurement techniques used in the clinical studies but under controlled conditions. These experiments identified a non-linear conductance-absolute volume relationship and demonstrated for the first time that the calibration coefficient, α_SV produced a significant, volume-dependent measurement error. These experiments also demonstrated that conductance volume measurements were adversely influenced by other electrical signals. The ventricular electrogram produced clinically important measurement error that has not previously been described. Two clinical studies were then undertaken to investigate the separate effects of the bidirectional cavo-pulmonary anastomosis (BCPA) and the completion total cavo-pulmonary connection (TCPC). These studies represent the core of the thesis. Both procedures were associated with significant changes in the pressure and volume conditions of the dominant ventricle. In addition, the BCPA was associated with a substantial and immediate improvement in ventricular systolic function but this was accompanied by an increase in diastolic chamber stiffness. By contrast, the TCPC was not associated with a significant change ventricular systolic or diastolic function in spite of the changes in ventricular load. Comparable changes were observed in patients with a dominant ventricle of either left or right ventricular morphology. These studies provide a more detailed understanding about the acute events that accompany surgical palliation in children with functionally single ventricle anatomy. These findings confirm the validity of staged surgical palliation in the management of these children.

Name dc:type.qualificationname

d_ph

Level dc:type.qualificationlevel

d_ph

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• McGuirk, Simon Prosser

• RD Surgery
• RJ Pediatrics