Left atrial appendage closure for stroke prevention in patients with atrial fibrillation and hereditary hemorrhagic telangiectasia

Safety of reduced or absent antithrombotic therapy after left atrial appendage closure in patients affected by hereditary haemorrhagic telangiectasia and atrial fibrillation

BACKGROUND

Left atrial appendage (LAA) closure represents a novel therapeutic chance for patients with contraindications to long-term anticoagulation therapy, such as those affected by Hereditary Hemorrhagic Telangiectasia (HHT) and atrial fibrillation (AF). Nevertheless, current experts' indications suggest the post-procedural administration of antithrombotic therapies to minimize the residual thromboembolic risk due to AF and to the need for device endothelialization. The aim of our study was to investigate the safety and effectiveness of LAA closure in preventing arterial thromboembolism in a very high-bleeding risk group, such as HHT patients, who are at risk not to tolerate even the mild post-procedural antithrombotic therapy usually recommended.

METHODS

Eight HHT-affected patients with non-valvular AF, high-bleeding risk and/or known intolerance to antiplatelet and anticoagulant therapy were treated with interventional LAA occlusion with the Amplatzer™ Cardiac Plug™ and Amplatzer™ Amulet™ devices. Device implantation was successful in all patients.

RESULTS

Post-procedural antiplatelet/anticoagulation therapy was attempted in seven patients: adherence to therapy exceeded six months only for one, while four patients suspended all antithrombotic medications within 30 days from the procedure due to an increase in bleeding frequency and/or severity and the other two discontinued treatment within six months; a single patient was not prescribed any antithrombotic therapy. At a medium follow-up of 22.4±14.3 months no thromboembolic episodes attributable to AF or device related thrombosis were reported. Two deaths were recorded 1231 and 783 days after the procedure which were classified as unrelated to any cerebral or cardiovascular accident.

CONCLUSIONS

Our study suggests that the percutaneous LAA closure in HHT patients with AF could be safe and effective in preventing arterial systemic thromboembolism, also in the presence of reduced or absent post-interventional antithrombotic treatment. LAA occluder implantation can represent a valid and potentially life-saving alternative to lifelong anticoagulant therapy in HHT, as in other very high-bleeding risk patients.

Percutaneous left atrial appendage closure-An alternative strategy for anticoagulation in atrial fibrillation and hereditary hemorrhagic telangiectasia?

Many patients with hereditary hemorrhagic telangiectasia (HHT) are unable to sustain oral anticoagulation (OAC) because of severe epistaxis, gastrointestinal (GI) bleeding and the risk of life-threatening bleeding from cerebral arteriovenous malformations (CAVMs) or pulmonary arteriovenous malformations (PAVMs). In patients with atrial fibrillation (AF), most thromboembolic complications arise from the left atrial appendage (LAA) and percutaneous transcatheter LAA closure proved to be non-inferior to OAC at mid-term follow-up. We report our experience with LAA closure in HHT with a follow-up of 12 months. Percutaneous LAA closure was performed in five patients with both HHT and high thromboembolic risk AF (CHA2DS2-VASc score ≥2) without peri-procedural complications. At 3 months no thromboembolic event occurred. After 12 months one patient had a transient ischemic attack while another patient had recurrence of stroke, this latter patient had a significant stenosis of the carotid artery and an incomplete closure of the LAA without any signs of thrombus on echocardiogram. Both patients had a non-treatable pulmonary right-to-left shunt (RLS). Percutaneous closure of the LAA may provide an alternative strategy to long-term OAC therapy in HHT patients with AF induced high stroke risk and intolerance for OAC.

Catheter ablation in combination with left atrial appendage closure for atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope. Patients with AF have a five-fold higher risk of stroke. Oral anticoagulation (OAC) with warfarin is commonly used for stroke prevention in patients with AF and has been shown to reduce the risk of stroke by 64%. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range. These issues, together with poor appreciation of the risk-benefit ratio, unawareness of guidelines, or absence of an OAC monitoring outpatient clinic may explain why only 30-60% of patients with AF are prescribed this drug. The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF, highlight the need for effective non-pharmacological approaches to treatment. One such approach is catheter ablation (CA), a procedure in which a radiofrequency electrical current is applied to regions of the heart to create small ablation lesions that electrically isolate potential AF triggers. CA is a well-established treatment for AF symptoms, that may also decrease the risk of stroke. Recent data showed a significant decrease in the relative risk of stroke and transient ischemic attack events among patients who underwent ablation compared with those undergoing antiarrhythmic drug therapy. Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation, another approach to stroke prevention is to physically block clots from exiting the LAA. One method for occluding the LAA is via percutaneous placement of the WATCHMAN LAA closure device. The WATCHMAN device resembles a small parachute. It consists of a nitinol frame covered by fabric polyethyl terephthalate that prevents emboli, but not blood, from exiting during the healing process. Fixation anchors around the perimeter secure the device in the LAA (Figure 1). To date, the WATCHMAN is the only implanted percutaneous device for which a randomized clinical trial has been reported. In this study, implantation of the WATCHMAN was found to be at least as effective as warfarin in preventing stroke (all-causes) and death (all-causes). This device received the Conformité Européenne (CE) mark for use in the European Union for warfarin eligible patients and in those who have a contraindication to anticoagulation therapy. Given the proven effectiveness of CA to alleviate AF symptoms and the promising data with regard to reduction of thromboembolic events with both CA and WATCHMAN implantation, combining the two procedures is hoped to further reduce the incidence of stroke in high-risk patients while simultaneously relieving symptoms. The combined procedure may eventually enable patients to undergo implantation of the WATCHMAN device without subsequent warfarin treatment, since the CA procedure itself reduces thromboembolic events. This would present an avenue of treatment previously unavailable to patients ineligible for warfarin treatment because of recurrent bleeding or other warfarin-associated problems. The combined procedure is performed under general anesthesia with biplane fluoroscopy and TEE guidance. Catheter ablation is followed by implantation of the WATCHMAN LAA closure device. Data from a non-randomized trial with 10 patients demonstrates that this procedure can be safely performed in patients with a CHADS2 score of greater than 1. Further studies to examine the effectiveness of the combined procedure in reducing symptoms from AF and associated stroke are therefore warranted.