Subgroup analysis
The treatment effect was distinct between the patients with
supravalvular and subvalvular EVA sites. For multiple-comparison, either
strategy was superior in IA success rate to treat its ipsilateral EVA
sites as compared with contralateral ones (P<0.0083) (Table
2). In the logistic regression model, patient sex, age, presence of VT,
PVC frequency, sharp potential reversal at target, EVA site
(supravalvular or subvalvular), initial ablation strategy, RVOT
diameter, and PA diameter were included to adjust clinical confounders
(Table 2). The EVA site was the only baseline characteristic with a
remarkable multiplicative treatment interaction
(Pinteraction<0.001). The AERI was calculated
as 95.0%+85.7%-46.7%-28.6%=105.2%, suggesting a large magnitude of
super-addictive interaction between the EVA site and its ipsilateral
strategy. In patients with supravalvular EVA sites, supravalvular
strategy was associated with a lower risk of IA failure (HR 0.021, 95%
CI 0.002-0.214; P=0.001). Whereas in patients with subvalvular EVA
sites, the supravalvular strategy was associated with a higher risk of
IA failure (HR 7.000, 95% CI 1.098-44.607; P=0.039). The supravalvular
strategy had fewer ablation applications in treating supravalvular EVA
sites than subvalvular EVA sites, as well as the subvalvular strategy
(P<0.0083) (Table 3).