Heart Rhythm.2015 Jul;12(7):1524-1531

Feasibility and clinical efficacy of left atrial ablation for the treatment of atrial tachyarrhythmias in patients with left atrial appendage closure devices.

 

Christian-H. Heeger, Andreas Rillig, Feifan Ouyang, Karl-Heinz Kuck and Roland Richard Tilz

Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany

 

Abstract

Background: Left atrial appendage (LAA)-closure devices have been recently introduced as an alternative for oral anticoagulation (OAC) in patients with non-valvular atrial fibrillation (AF). Due to potential overlap of ablation target areas and the previously implanted LAA-closure device and potential complications such as mechanical damage to the device, left atrial (LA) ablation remains a subject of debate in these patients.

Objective: We report on the feasibility and clinical efficacy of LA ablation after implantation of LAA-closure devices.

Methods: Eight patients (6/8 male, 69±8 years) with symptomatic paroxysmal (n=5) or persistent AF (mean CHA2DS2-VASc score=3.6±0.7, mean HAS-BLED score=3.6±1.5) and previously implanted WATCHMANTM (7/8) or AMPLATZER Cardiac PlugTM (1/8) LAA-closure devices received radiofrequency-based LA ablation (4/8 circumferential pulmonary vein isolation (PVI), 4/8 PVI and additional LA linear lesions or complex fractionated atrial electrograms) after a mean of 201 (41-756) days after LAA-closure.

Results: Successful LA ablation was achieved without device interference or periprocedural complications. After a mean of 503 (113-1006) days, transesophageal echocardiography (TEE) was performed in all patients to assess for device-related complications. No device dislocation or leakage was observed. In 1/8 patients (12.5%) a device-related thrombus was found despite therapeutic OAC with dabigatran. Five/eight patients (63%) remained in stable sinus rhythm and no bleeding events or stroke occurred during a follow-up of 554 (218-1006) days.

Conclusion: LA ablation after LAA-closure appears to be feasible. Device-related thrombus formation in one patient suggests the need for further TEE examinations following LA ablation after LAA-closure device implantation.

PMID: 25769512

 

Summary

Atrial fibrillation (AF) is recently the most common arrhythmia in the developed world. The risk for stroke is increased in AF and estimated to be as high as 5% per year. The left atrial appendage (LAA) is know as the primary source for thrombus formation and cardiac embolism in patients with non-valvular AF.1 Recently, percutaneous LAA-closure devices were introduced for stroke prevention and safety and feasibility have been demonstrated in large clinical trials.2 Pulmonary vein isolation (PVI) is an established treatment strategy for symptomatic, drug-refractory AF. Due to potential overlap of ablation target areas and a previously implanted LAA-closure device, ablation for the treatment of left atrial tachyarrhythmias (LATA) remains a subject of debate. In the Heart Rhythm July issue of 2015 we published the first data regarding feasibility and clinical efficacy of LA ablation in patients with previously implanted LAA-closure devices.3

Eight consecutive patients (mean age 69±8 years) after successful percutaneous LAA-closure with subsequent LA ablation for the treatment of paroxysmal (n=5/8) or persistent AF (n=3/8) were evaluated. In all patients, successful LAA-occlusion was performed. No peri-interventional complications occurred and all patients were discharged at day one after the procedure. After LAA-closure, 6/8 patients were treated with oral anticoagulation (OAC), whereas 2/8 patients were treated with dual antiplateled therapy (DAPT) due to a contraindication to OAC. After a mean of 74 (41-122) days a control TEE was performed. No device-related thrombus formation, device dislocation or leakage was found.

LA ablation was performed 201 (41-756) days following LAA-closure. All patients underwent preinterventional TEE to exclude possible intracardiac thrombi and to evaluate the status of the previously implanted LAA-closure device concerning device leakage or dislocation. Irrigated radiofrequency (RF) was performed for ablation. To avoid device-related complications visual monitoring of impedance was performed. No device-related thrombus formation, device dislocation or leakage was found on TEE one day prior to the ablation procedure.

Ablation at the index procedure included PVI in 6/8 patients, re-isolation of the left PVs in 2/8 patients (closure of an antero-inferior gap: n=1, ablation of ostial potentials along the ridge between the left PVs and the LAA: n=1), ablation of an anterior line in 3/8 patients, mitral isthmus line ablation in 3/8 patients, and ablation of CFAEs within the LA and CS in one patient. All PVs were successfully re/isolated and bidirectional block was achieved at all ablation lines. No periprocedural complications occured, and no automatic generator shut-down was found due to erroneous impedance measurements in the near of the LAA-closure device. Stable sinus rhythm could be achieved in all patients. After LA ablation, OAC was achieved (n=1/8 warfarin, INR 2-3; n=3/8 rivaroxaban (20mg daily); n=2/8 apixaban (5mg twice daily); n=2/8 dabigatran (150mg twice daily) and was continued for at least three months after ablation. After 3 months, ASA (100mg daily) was prescribed in 4/8 patients and clopidogrel (75mg daily) in 1/8 patient whereas in n = 2/8 patients apixaban half of the regular dose (2.5mg twice daily) was continued. Due to a device-related thrombus formation, one patient treated initially with dabigatran was changed to rivaroxaban (20mg daily).

All patients received TEE evaluation after a mean of 503 (113-1006) days following the LA ablation procedure. No device dislocation or leakage was found. In one patient, a device-related thrombus (10x12mm) was detected 113 days after LA ablation whilst treated with dabigatran (150mg twice daily), Figure 1. OAC was arbitrarily changed to rivaroxaban (20mg daily) and a further TEE was performed at 4 months follow-up. At this time the thrombus remained unchanged and OAC was changed to apixaban (5mg twice daily). TEE was then repeated at 5, 6, 8, 10, 12 and 15 months follow-up after LA ablation. Under treatment with apixaban, a continuous reduction in the thrombus size was observed, which resolved 616 days (>20 months) after the LA ablation. This patient remains under surveillance and is maintained on therapeutic apixaban (5mg twice daily). After a mean follow-up of 554 (218-1006) days 5/8 patients (63%) were in stable sinus rhythm without documentation of any LATA. In the other 3/8 (38%) patients LATA-recurrence was detected. No bleeding events nor stroke, TIA or peripheral embolism occurred in this study population.

 

CH Figure 1

Figure 1: WATCHMANTM LAA-closure device after LA ablation. Transesophageal echocardiography findings of the left atrium (LA) and post LA ablation in a patient after left atrial appendage (LAA) closure with the WATCHMANTM device. At follow-up, 113 days post LA ablation, a sessile device-related thrombus (size: 10x12mm, attached to the superior-anterior part of the device (red arrow) was detected while the patient was under therapeutic dabigatran. AV = aortic valve, LA = left atrium, WATCHMAN = WATCHMANTM LAA-closure device

 

Safety and Feasibility of LA ablation after LAA-closure

Due to an increasing number of patients with AF and increasing rate of LAA-closure device implantations, ablation for the treatment of symptomatic drug-refractory AF remains a subject of debate in patients after LAA-closure.4, 5 The present examination found no peri-procedural complications. Yet, device-related thrombus was detected in one patient despite OAC 113 days after ablation. The thrombus was persistent for >20 months despite continuation of therapeutic OAC with alternative NOACs. We cannot exclude that the device-related thrombus in this patient occurred coincidentally. However, the patient had no device-related thrombus on TEE 62 days after LAA-closure, which was performed one day prior to ablation but a thrombus in the TEE after ablation. Consequently, although a causal relation between the procedure and the thrombus formation on the LAA-closure device remains unproven it is very likely. Ablation was performed just 63 days after LAA-closure. Therefore it may be possible that the device was covered by a thin fragile layer of endothelial tissue, which could be potentially injured during the procedure and promoting thrombus formation. As a consequence, we recommend follow-up TEE examinations prior to termination of OAC to assess for device-related complications after LA ablation in these patients. In the case of device-related thrombus formation it seems to be advisable to extend OAC, despite the increased for bleeding events, to prevent ischemic complications. No data is available for this specific patients population. Therefore, we suggest to individually discus the indication for OAC. PVI has proven to be an effective treatment strategy for patients with PAF even after long-term follow-up.6 In our study, PVI as well as more complex LA ablation techniques including linear lines, LAA-isolation and CFAE ablation were performed. With 5/8 patients remaining in stable SR within follow-up, we are suggesting LA ablation in patients with previously implanted LAA-closure devices to be feasible and effective.

 

Conclusion

LA ablation after LAA-closure appears to be feasible resulting in successful PVI and bidirectional blockade of additional LA ablation lines and stable SR. Device-related thrombus formation may occur following ablation and suggests the need for postprocedural examinations to improve patient´s safety. Therefor we strongly recommend TEE evaluations after LA ablation in patients with previously implanted LAA-closure devices to assess for device-associated complications.

 

References

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