Impact of Fontan Fenestration on Long-Term Outcomes: A Propensity Score-Matched Analysis

Abstract

Background The long-term impact of fenestration at the time of Fontan operation remains unclear. We aimed to review the early and long-term impact of Fontan fenestration in the Australia and New Zealand cohort. Methods and Results We reviewed 1443 patients (621 fenestrated, 822 nonfenestrated) from the Australia and New Zealand Fontan registry. Data were collected on preoperative demographics, operative details, and follow-up. Propensity-score matching was performed to account for the various preoperative and operative differences and risk factors. Primary outcomes were survival and freedom from failure. Median follow-up was 10.6 years. After propensity-score matching (407 matched pairs), there was no difference in survival (87% versus 90% at 20 years; P=0.16) or freedom from failure (73% versus 80% at 20 years; P=0.10) between patients with and without fenestration, respectively. Although patients with fenestration had longer bypass and cross-clamp times (P<0.001), there was no difference in hospital length of stay or prolonged pleural effusions (P=0.80 and P=0.46, respectively). Freedom from systemic and Fontan circuit thromboembolism was higher in the nonfenestrated group (89%; 95% CI, 88%-95%) than the fenestrated group (84%; 95% CI, 77%-89%; P=0.03). There was no difference in incidence of plastic bronchitis, protein-losing enteropathy, New York Heart Association Class III/IV symptoms, or Fontan takedown. Conclusions In the propensity score-matched analysis we have demonstrated no difference in long-term survival or freedom from Fontan failure in patients with and without fenestration. There was a higher incidence of long-term thromboembolic events in patients with fenestration. Overall, it appears that fenestration in Fontan circulation does not bring long-term benefits.

Keywords: fenestration; risk factor; survival; thromboembolism; univentricular.

Figure 1. Comparison of unmatched cohorts.

A, Survival in unmatched cohorts. Log‐rank analysis of the unmatched cohorts demonstrated better survival in the nonfenestrated cohort (P=0.04). This result may pertain to the higher preoperative risk factors in the fenestration group, influencing the decision to perform fenestration. B, Freedom from Fontan failure in unmatched cohorts. Log‐rank analysis of the unmatched cohorts demonstrated improved freedom from Fontan failure in the nonfenestrated group. Similarly, this is likely attributed to higher risk patients undergoing fenestration, which is unaccounted for in the unmatched analysis (P=0.01). C, Freedom from thromboembolic events in unmatched cohorts. Log‐rank analysis of the unmatched cohorts showed a higher incidence of thromboembolic events in the fenestrated group. Although this may be attributed to higher preoperative risk factors in the fenestration group, the presence of the fenestration may also predispose the group to thromboembolism (P=0.01).

Figure 2. Comparison of propensity score–matched cohorts.

A, Survival in propensity score–matched cohorts. Log‐rank analysis of the propensity score–matched cohorts showed no difference in survival (P=0.16). The lack of difference demonstrates the influence of preoperative risk factors and the lack of impact of the fenestration on long‐term survival. B, Freedom from Fontan failure in propensity score–matched cohorts. Log‐rank analysis of the propensity score–matched cohorts showed no difference in freedom from Fontan failure (P=0.10). Similarly, the lack of difference demonstrates the influence of preoperative risk factors and the lack of impact of the fenestration on long‐term survival. C, Freedom from thromboembolic events in propensity score–matched cohorts. Log‐rank analysis of the propensity score–matched cohorts showed a higher incidence of thromboembolic events in the fenestrated group (P=0.03). Given this difference persists after propensity‐score matching, it demonstrates an association between fenestration and long‐term thromboembolic events that cannot be attributed to the cohort demographics.

Figure 3. The impact of Fontan fenestration on long‐term outcomes.

Propensity‐score matching was performed on 1443 patients, producing 407 matched pairs for an intention‐to‐treat analysis. Log‐rank tests were performed on time‐dependent variables to test the differences between groups. No difference in survival or freedom from failure was detected between the 2 groups. Patients undergoing fenestration did have an increased risk of thromboembolic events during follow‐up.