PS matching sensitivity analysis
A PS was used to match patients in a 1:1 fashion for NC-ABL vs C-ABL
groups accordingly to all variables identified as independent predictors
of VT recurrence and mortality. The PS utilized the covariates: ES at
presentation, LVEF, NYHA class III/IV, IHD and age. The PS matched two
groups of 43 patients. NC-ABL and C-ABL patients had a mean age of 60 ±
14 and. 61 ± 12 years, being 86% and 77% of male sex and 72% being
redo procedures in both groups, respectively. Both groups presented with
well-matched baseline characteristics (Table 4), except for atrial
fibrillation, with a higher incidence in the NC-ABL group (N=10, 23% vs
N=2, 5%, P=0.026). Only 2 patients underwent epicardial ablation at
index procedure in the NC-ABL group, while 37 (86%) patients were
treated with an epicardial ablation and 6 (14%) patients had a previous
epicardial ablation in the C-ABL group (P<0.001). During a
mean follow-up of 3±2 years, 27 (63%) NC-ABL patients had VT recurrence
and 10 (23%) in the C-ABL group (P=0.003). The yearly rates of VT
recurrence were 34%/year for NC-ABL vs. 11%/year for C-ABL (P=0.003).
Multivariate survival analysis in the PS population identified only
C-ABL (HR=0.42, 95%CI 0.20─0.88, P=0.023) as an independent predictor
of VT recurrence (Figure 2) in both ischemic and nonischemic dilated
cardiomyopathy (P for interaction = 0.110), but only in patients with a
previous endocardial ablation (P for interaction = 0.03).