Abstract 16568: Risk Factors for Prolonged Length of Stay Following Stage II procedure in the Single Ventricle Reconstruction Trial
Background: The Single Ventricle Reconstruction trial randomized patients with single right ventricle lesions to a modified Blalock-Taussig shunt (MBTS) or Right Ventricle to Pulmonary Artery Shunt (RVPAS) at the Norwood. This study describes outcomes at the stage II procedure and risks associated with a longer length of hospital stay (LOS).
Methods: We examined the association of shunt type in place at the end of the Norwood operation on stage II outcomes using univariate analysis. Cox regression and bootstrapping were used to evaluate risk factors for increased LOS. We defined a hazard ratio (HR) >1 to indicate longer LOS. We also compared characteristics of in-hospital deaths to survivors.
Results: Among the 549 subjects in the analytic cohort, 401 (73%) underwent a stage II procedure. There were 8 subjects excluded: 6 had a Kawashima, 1 had a stage II at 23 months and 1 had an unknown date of stage II. Of the 393 subjects analyzed, 172 had MBTS and 221 RVPAS. Median LOS was 8 d (IQR: 6, 14) and did not differ between MBTS and RVPAS. There were 17 hospital deaths (4%) and 3 transplants (1%) before discharge, with no difference between shunt types. There were no differences between shunt types in stage II ventilator time, ICU LOS, number of additional cardiac procedures or complications. Longer LOS was independently associated (R2=0.26) with center, longer post-Norwood LOS (HR 1.92 per log day, P<0.001), non-elective stage II (HR 1.79, P<0.001) and branch PA stenosis (HR 1.56, P<0.001). Median LOS was 6 d when none of these clinical risk factors were present and 13 d when 3 risk factors were present. A multivariable model that included subjects in whom PVR was measured (N=253) found the same significant risk factors except that higher PVR (HR 1.23, P=0.004) instead of PA stenosis was associated with longer LOS. In-hospital deaths more often had a non-elective Stage II (65% vs. 32%, p=0.009), ≥ moderate atrioventricular valve regurgitation (AVVR) on pre-stage II echo (75% vs. 24%, P<0.001) and had AVV repair at the time of stage II operation (53% vs. 9%, p <0.001).
Conclusion: Norwood LOS, PA stenoses or high PVR and non-elective reasons for timing of the stage II procedure, but not shunt type, are independently associated with longer LOS. Moderate to severe AVVR is a risk factor for death.
- © 2012 by American Heart Association, Inc.