Systemic-to-pulmonary collateral flow, as measured by cardiac magnetic resonance imaging, is associated with acute post-Fontan clinical outcomes

Abstract

Background: Systemic-pulmonary collateral (SPC) flow occurs commonly in single ventricle patients after superior cavo-pulmonary connection, with unclear clinical significance. We sought to evaluate the association between SPC flow and acute post-Fontan clinical outcomes using a novel method of quantifying SPC flow by cardiac magnetic resonance (CMR) imaging.

Methods and results: All patients who had SPC flow quantified by CMR imaging before Fontan were retrospectively reviewed to assess for acute clinical outcomes after Fontan completion. Forty-four subjects were included who had Fontan completion between May 2008 and September 2010. SPC flow prior to Fontan measured 1.5±0.9 L/min/m(2), accounting for 31±11% of total aortic flow and 44±15% of total pulmonary venous flow. There was a significant linear association between natural log-transformed duration of hospitalization and SPC flow as a proportion of total aortic (rho=0.31, P=0.04) and total pulmonary venous flow (rho=0.29, P=0.05). After adjustment for Fontan type and presence of a fenestration, absolute SPC flow was significantly associated with hospital duration ≥7 days (odds ratio [OR]=9.2, P=0.02) and chest tube duration ≥10 days (OR=22.7, P=0.009). Similar associations exist for SPC flow as a percentage of total aortic (OR=1.09, P=0.048 for hospitalization ≥7 days; OR=1.24, P=0.007 for chest tube duration ≥10 days) and total pulmonary venous flow (OR=1.07, P=0.048 for hospitalization ≥7 days; OR=1.18, P=0.006 for chest tube duration ≥10 days).

Conclusions: Increasing SPC flow before Fontan, as measured by CMR imaging, is associated with increased duration of hospitalization and chest tube following Fontan completion.

Figures

Figure 1

Schematic showing the locations of the phase-contrast velocity maps used to calculate systemic-pulmonary collateral flow. Yellow bars represent the locations of the velocity maps.

Figure 2

Scatter plot demonstrating association between systemic-pulmonary collateral flow measured both as a percentage of total aortic flow (panel a) and total pulmonary venous flow (panel b) and natural log-transformed total hospital duration. Best-fitting lines from linear regression are overlaid.

Figure 2

Scatter plot demonstrating association between systemic-pulmonary collateral flow measured both as a percentage of total aortic flow (panel a) and total pulmonary venous flow (panel b) and natural log-transformed total hospital duration. Best-fitting lines from linear regression are overlaid.

Figure 3

Measures of total systemic-pulmonary collateral flow (L/min/m2) based on duration of hospitalization. Statistical difference tested by Wilcoxon Rank-Sum.

Figure 4

Measures of total systemic-pulmonary collateral flow (L/min/m2) based on chest tube duration. Statistical difference tested by Wilcoxon Rank-Sum.

Figure 5

Measures of systemic-pulmonary collateral flow expressed as a proportion of total aortic and total pulmonary venous flow, based on chest tube duration. Statistical differences tested by Wilcoxon Rank-Sum.