Abstract 18201: Branch Pulmonary Artery Flow Reversal Can be Identified by Cardiac Magnetic Resonance and is Associated with Increased Collateral Flow Burden in Patients with Superior Cavopulmonary Connections
Background: We have described and validated a method of measuring systemic to pulmonary arterial collateral flow (CollF) in pts with superior cavopulmonary connections (SCPC) using magnetic resonance phase contrast velocity mapping (PC-MRI). We have shown that CollF in pts with SCPC correlates with acute Fontan outcomes. We have identified flow reversal in both the left pulmonary artery (LPA) and right upper lobe branch pulmonary artery (RUL) and now describe our experience with identifying this phenomenon, as not recognizing it will potentially cause significant underestimation of the CollF by PC-MRI. We hypothesized that LPA or RUL flow reversal is readily identified by time resolved gadolinium angiography (TWIST) and PC-MRI, and is associated with high CollF burden.
Methods: We reviewed our database of 112 SCPC pts who had CollF prospectively measured to identify pts with either LPA or RUL flow reversal. They were compared to pts without flow reversal using unpaired Student t-test (p<0.05 significant).
Results: 8 SCPC pts had flow reversal, 6 in RUL and 2 in LPA, representing 7% of pts enrolled. Reversal could be visualized by TWIST and PC-MRI in each case. CollF burden was significantly higher in flow reversal pts than those without (2.2±0.7 vs. 1.6±0.7 L/min/m2, p=0.02), and was a greater percent of aortic flow (42±13% vs. 33±11%, p=0.04). One pt with LPA reversal had prior LPA thrombosis and an LPA stent placed, while the other had severe diffuse LPA hypoplasia (See Figure B). One pt with RUL flow reversal had severe proximal RUL stenosis (see Figure A) and another had severe pulmonary vein stenosis.
Conclusions: Pulmonary artery flow reversal can be identified by TWIST and PC-MRI in pts with SCPC, and occurred in 7% of pts with CollF quantified. Potential etiologies included proximal PA obstruction and pulmonary vein obstruction. Branch PA flow reversal is associated with increased CollF burden.
- © 2012 by American Heart Association, Inc.