Introduction: Endocardial left ventricular (LV) ablation is associated with an increased risk of thromboembolic events. While many operators prescribe a course of post-operative antiplatelet or oral anticoagulant (OAC) medication to prevent thromboembolism, the benefit of this approach is unknown. Furthermore, the safety of using direct OACs (DOACs) for this indication is uncertain. We performed a single-centre retrospective observational study to evaluate the risk of thromboembolism following endocardial LV ablation in relation to the type of post-procedural antithrombotic regimen used.
Methods: We included patients with significant structural heart disease who had undergone endocardial LV ablation at King’s College Hospital over a 6-year period (2013–8). We excluded patients with focal ablation for ventricular ectopics and a structurally normal heart. Intraprocedural heparin was used in all cases aiming for an ACT >250. Patients on an OAC pre-procedure for another indication continued on the same drug post-procedure. DOACs were stopped at least 24 hours pre-procedure and restarted the following day assuming haemostasis had been achieved. Warfarin was continued at the operator’s discretion and if stopped restarted the following day. For patients without a pre-existing OAC indication post-procedural antithrombotic drug use was at the operator’s discretion and based on the amount of ablation performed. For patients with focal ablation antiplatelet medication alone was used. For patients with more widespread substrate-based ablation a course of OAC was prescribed. We evaluated the incidence of thromboembolic and bleeding complications in the first 3 months post-procedure, as events during this time period were most likely to be procedure related.
Results: Of 259 ventricular ablations, 116 involved endocardial LV ablation in patients with significant structural heart disease (n=108). The majority were male (n=101, 94%), with an ICD/CRTD (n=86, 80%) and underlying coronary artery disease (n=86, 80%). The indication for ablation was acute VT storm in 44% (n=51) and symptomatic ventricular arrhythmias in the remaining 56% (n=65). Fifty-two patients were already on an OAC prior to their procedure (42 warfarin, 10 DOAC), for which the most frequent indication was AF (n=36). Post procedurally an OAC was used in 82 cases (40 NOAC and 42 warfarin) and 34 cases had anti-platelet medication alone. Of the patients not on an OAC pre-procedure, the length of course of OAC therapy ranged from 4–12 weeks post-procedure. Two patients suffered acute peri-procedural thromboembolic events – one TIA and one stroke (with new LV mural thrombus detected despite perioperative anticoagulation). During 3 months’ subsequent follow-up, no patient suffered a stroke or TIA, but one (taking a DOAC), suffered a subdural haematoma following a fall.
Conclusion: Intraprocedural cerebral events are rare but not absent in this high-risk group undergoing extensive endocardial ablation and frequent hypotensive episodes. However, a short course of OAC following substrate-based LV endocardial ablation is associated with a low rate of post-procedural thromboembolism. Although the numbers were small, warfarin and DOACs gave comparable results.
