The Fontan Cross-Sectional Study database included 546 subjects, of whom 7 were excluded because their index surgery was a Fontan conversion. Mean age at Fontan was 3.4±2.1 years with a mean age at enrollment of 11.9±3.4 years and a mean time since Fontan of 8.6±3.4 years. Of the 539 included subjects, 80 (15%) had undergone coiling of APCs prior to the Fontan (“coil group”) and 459 had not (“no coil group”). Of the 7 excluded subjects, 1 had undergone APC coiling and 6 had not.
The percentage of subjects undergoing pre-Fontan coiling varied significantly by center (), with a range of 0-30% (p<0.001). There was no association between the percentage of subjects undergoing coiling and center enrollment volume: the center with the lowest percentage of subjects who underwent coil occlusion (0%) enrolled 102 subjects in the study while the center with the highest percentage (30%) enrolled 103.
Frequency of Coil Embolization of Aortopulmonary Collateral Vessels Among Centers
Compared to subjects who never received APC coils (), the coil group was older at Fontan and was more likely to have a single right ventricle. At pre-Fontan testing, the coil group was also more likely to have moderate or severe atrioventricular valve regurgitation by pre-Fontan echocardiography, and slightly higher systemic oxygen saturation at pre-Fontan catheterization. Furthermore, those with pre-Fontan APC coils were more likely to have undergone additional catheter interventions to occlude veno-venous collaterals. Pre-Fontan characteristics were otherwise similar between the two groups, including weight-for age, degree of pre-Fontan ventricular dysfunction on echocardiography, ventricular end-diastolic pressure, and presence of pulmonary artery stenosis or superior vena cava obstruction at catheterization.
Subject Characteristics at Fontan Completion According to APC Coil Status
As shown in , subjects in the coil group underwent Fontan completion in a more recent calendar year and were more likely to have had a prior superior cavopulmonary anastomosis. Fontan surgery in the coil group, compared to the no-coil group, was more likely to include a surgical fenestration, and the Fontan connection itself was more likely to be an extracardiac Fontan and less likely to involve an atriopulmonary connection. Cardiopulmonary bypass times were similar in the two groups (p=0.99).
In univariable analysis, length of stay after Fontan was shorter for subjects in the coil group (median 10.5 days vs. 12.0 days, p=0.03). The coil group also had a greater median number of interventions at cardiac catheterizations after the Fontan procedure (1 vs. 0, p=0.04). Exercise test results, ejection fraction and general health status, as reflected in the Physical Summary score of the CHQ-PF50, were similar in the groups at the time of cross-sectional testing. No other post-Fontan outcome variable or in-person test result differed significantly between those with and without pre-Fontan APC coils. There was no correlation between time from coil placement to Fontan completion and length of stay after Fontan (Spearman R = 0.015, p=0.9)
In multivariable regression, adjusting for year of Fontan and surgical fenestration, the two groups were similar in their post-Fontan hospital length of stay (). To further reduce the risk of residual confounding, we restricted the analyses to subjects who underwent a superior cavopulmonary anastomosis prior to Fontan completion (75% of the sample). Even in this subgroup, LOS did not differ significantly between the coil (n=78) versus no-coil (n=327) groups in either unadjusted (median 11 days for both groups, p=0.28) or multivariable analyses (hazard ratio for remaining in the hospital 0.90, 95% CI 0.70-1.16, p=0.43). Furthermore, length of stay was also similar between subjects from the two centers with the highest and lowest frequency of APC coils (median 9.5 vs. 10 days, respectively), both large tertiary care centers enrolling a similar number of subjects.
Post-Fontan Hospital Length of Stay After Adjustment for Fenestration and Year of Fontan
Among the secondary outcomes (), even after adjusting for type of Fontan connection and years since Fontan completion, the coil group was more likely to have had one or more post-Fontan catheter interventions (odds ratio (OR) 1.74, 95% CI 1.04-2.91, p=0.03), consisting primarily of additional APC coils (23% vs. 13% of subjects with post-Fontan catheter interventions in the coil vs. no-coil group, respectively). The groups did not, however, differ in any other outcomes, including occurrence of pleural effusions, late complications following Fontan completion and test results at cross-sectional follow-up. There were also no significant differences in frequency of neurodevelopmental problems reported on the CHQ-PF50 including developmental delay (p=0.88), learning problems (p=0.47), attention problems (p=0.82), speech problems (p=0.53), or behavioral problems (p=0.92).
Post-Fontan Outcomes for the Coil vs. the No-Coil Group After Adjustment for Covariates*
We explored whether coils were more effective in subgroups of subjects expected to have more APC flow because of their oxygen saturation or age at Fontan. We found no subject subset, defined by oxygen saturation or by age at Fontan, for whom APC coiling was significantly associated with shorter length of stay after the Fontan procedure. With regard to other outcomes, including those measured at cross-sectional follow-up, only one interaction reached statistical significance. An association between ejection fraction and APC coiling depended on age at Fontan (p=0.004); among those with Fontan performed at older ages (4 years or older), ejection fraction was lower in the coil group compared with the no coil group (55±13% vs. 59±11%, respectively).