Faculty Bibliography

OBJECTIVE:Systemic to pulmonary arterial collateral flow (CollF) is common in single ventricle patients with superior cavopulmonary connections (SCPC), although associations with CollF are not well understood. We previously described a method to quantify CollF by cardiac MRI (CMR). We sought to identify factors associated with CollF in a large cross section of patients with SCPC. METHODS:A retrospective observational cohort study of events from birth to study CMR was performed for all patients with SCPC who had CollF quantified by CMR. RESULTS:CollF was quantified in 96 patients at a median age of 2.6 (IQR 1.9-3.1) years and 2.1 (1.4-2.7) years after SCPC and measured 1.6±0.7 L/min/m(2) (33±11% of aortic flow and 48±16% of pulmonary venous flow). Significantly higher amounts of indices of CollF were associated with: duration of chest tubes (p≤0.05 for all), intensive care unit and hospital length of stay (p≤0.04 for all), higher O2 saturation at Stage 2 discharge (p=0.04 for CollF/aortic), female sex (p≤0.007 for CollF/aortic and CollF/pulmonary venous), and history of a Blalock-Taussig shunt (p<0.04 for CollF and CollF/aortic). Multivariable models were constructed to identify factors independently associated with CollF measures and included: female sex (p≤0.006 for all), O2 saturation at Stage 2 discharge (p=0.013 for CollF/aortic) and total chest tube days (p=0.001 for all). These models explained 20-22% of the variance in the outcomes. CONCLUSIONS:These data support hypotheses that perioperative morbidity and pleural inflammation play a role in CollF development and that CollF affects pulmonary blood flow.

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/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.