Outcomes after cavotricuspid isthmus ablation: predictors of new-onset atrial fibrillation and stroke according to anticoagulation strategy

Introduction

Management of oral anticoagulation (OAC) after cavotricuspid isthmus (CTI) ablation for common atrial flutter (CAF) remains controversial, particularly in patients without prior atrial fibrillation (AF). Meta-analyses suggest that discontinuing OAC after successful ablation may reduce bleeding risk without clearly increasing thromboembolic events. However, available evidence is limited, and randomized clinical trials are lacking.

Purpose

To evaluate the incidence of thromboembolic and bleeding events following CTI ablation and to identify potential predictors of new-onset AF and stroke during follow-up.

Methods

Prospective, single-center observational study including patients who underwent CTI ablation between Jan/22 and Dec/24. Baseline characteristics, AF history, CHA2DS2-VA score, and periprocedural findings were recorded; clinical outcomes during follow-up were registered.

Results

130 patients were included (82.3% male, mean age 67.4 ± 11.6 years), with a median CHA2DS2-VA score of 3 [1–4]. Prior AF was documented in 39%. Prior cardiomyopathy was present in 52.3% of patients, most commonly valvular (20%), hypertensive (16.2%) and ischaemic (10%) cardiomyopathies, with median left ventricular ejection fraction (LVEF) of 60% [48-60]. Left atrial (LA) enlargement was frequent (64.6%), with a median diameter of 43 [40-48] mm.

OAC was discontinued after a mean of 3.8 ± 3.1 months after CTI ablation in 44.6% of patients (those without prior AF or with low embolic risk). Over a mean follow-up of 24 ± 10 months, CAF recurrence was documented in one patient (time to recurrence 6 months), requiring repeat ablation. AF occurred in 27 patients (20.8%), 10 of them de novo (7.6%). Four embolic strokes (3.1%), six major (4.6%) and five minor (3.8%) bleeding events, and 12 deaths (9.2%) were recorded, none procedure related.

Patients who discontinued OAC had lower CHA2DS2-VA scores and less prior AF, with no significant differences in stroke, bleeding, or mortality (Table 1, Figure 1). In multivariable analysis, larger LA diameter showed a trend toward an increased risk of new-onset AF (OR 1.10 per mm, 95% CI 0.97–1.25, p = 0.15) among patients without previous AF, whereas sex, age, common risk factors, or cardiomyopathy were not significant predictors. Two embolic strokes occurred OAC-discontinued group; neither patients had documented AF prior or after the event, though one had a CHA2DS2-VA score of 3. No independent predictors of stroke were identified in the overall cohort.

Conclusions

Discontinuation of OAC after CTI ablation was performed in patients with low embolic risk and no prior AF, which was not associated with higher rates of events. LA enlargement might be a potential marker for new-onset AF during follow-up. These findings suggest that OAC discontinuation after successful CTI ablation may be safe in selected low-risk patients, whereas continued OAC should be considered in those with high CHA2DS2-VA scores or LA dilatation.Characteristics and cardiovascular eventKaplan-Meier event-free survival curves