Device related thrombosis after left atrial appendage occlusion: does thrombus location always predicts its origin?

Low Dose of Direct Oral Anticoagulants after Left Atrial Appendage Occlusion

The optimal antithrombotic strategy following left atrial appendage occlusion (LAAO) is not yet clearly established. Low-dose non-vitamin K antagonist oral anticoagulants (NOAC) might represent a valid alternative, but data regarding their usage is scarce. The aim of this study was to examine the efficacy and safety of low-dose NOAC compared to single (SAPT) or dual antiplatelet therapies (DAPT) after LAAO. We included consecutive patients with non-valvular atrial fibrillation who underwent LAAO and received low-dose apixaban, SAPT, or DAPT at discharge. The primary objective of this study included an efficacy endpoint (thromboembolic events and device related thrombosis (DRT)) and a safety endpoint (incidence of major bleeding) within the first three months after LAAO. A total of 139 patients were included. This group involved SAPT in 26 (18%), DAPT in 73 (53%), and apixaban in 40 (29%) patients. Follow-up at three-months showed no significant differences in the primary efficacy endpoint (2 (8%) SAPT, 3 (4%) DAPT and 0 (0%) apixaban; p value = 0.25). In contrast, the primary safety endpoint occurred more frequently in DAPT patients (7 (10%) DAPT, 0 (0%), SAPT and 0 with apixaban; p value = 0.03). Combining both efficacy and safety outcomes, low dose apixaban had a lower rate of events (2 (8%) with SAPT, 9 (12%) with DAPT and 0 (0%) with apixaban; p = 0.046). Low-dose apixaban after LAAO may be a valid alternative to DAPT and SAPT as depicted by the reduction in the occurrence of major bleedings and combined DRT/major bleedings respectively. Randomized data will be necessary to validate this strategy.

Pulmonary ridge coverage and device-related thrombosis after left atrial appendage occlusion

AIMS

The aim of this study was to evaluate the impact of pulmonary ridge (PR) coverage on both clinical and imaging follow-up outcomes in patients undergoing left atrial appendage occlusion (LAAO).

METHODS AND RESULTS

The study included consecutive patients with non-valvular atrial fibrillation who underwent LAAO with disc and lobe devices. Patients were classified into two groups according to the PR coverage. A total of 147 patients were included. Among these, the PR was covered in 109 (74%) and uncovered in 38 (26%). Successful implantation was achieved in 98.6%. No differences in procedural outcomes were observed between the groups. The rate of procedural major adverse events was 3% (only major bleedings and/or vascular access complications). No device embolisation, cardiac tamponade or in-hospital mortality was observed. After a mean follow-up of 1.77±2.2 years, the annualised ischaemic stroke and major bleeding rate was 1.3%/year and 6.5%/year, respectively, without differences between groups. At follow-up, patients with a covered PR presented a lower incidence of device-related thrombosis (DRT) (1%) than those with an uncovered PR (27%); p<0.001. In multivariable analysis, the presence of PR coverage emerged as an independent predictor of DRT.

CONCLUSIONS

Pulmonary ridge coverage was associated with a lower incidence of DRT after LAAO. Procedural and follow-up clinical outcomes did not differ between covered PR and uncovered PR patients.

Rationale and design of a randomized clinical trial to compare two antithrombotic strategies after left atrial appendage occlusion: double antiplatelet therapy vs. apixaban (ADALA study)

BACKGROUND

Data on antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO) is scarce and no randomized evaluation has been performed to demonstrate what is the best antithrombotic strategy. Up to date, different antithrombotic regimens with variable durations are currently used. In fact, the use of oral anticoagulation (OAC) or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel during the initial phase (∓ 3 months post-LAAO) has been proposed as valid strategies. However, antiplatelet and OAC therapies have never been compared in a randomized study after left atrial appendage closure (LAAC). The purpose of the present study is to ascertain an optimal antithrombotic strategy after LAAC in terms of safety and efficacy. The study will compare a novel OAC (NOAC) with a highly safety profile like apixaban 5 mg/12 h or 2.5 mg/12 h (after dose adjustment or in high-risk patients) with standard antiplatelet therapy with DAPT. The aim of the study was to compare a strategy of anticoagulation with apixaban 5 mg/2.5 mg bid to the current standard of care (DAPT with aspirin and clopidogrel) after LAAO in patients with non-valvular atrial fibrillation (AF).

METHODS

This is a phase IV multicenter randomized, open-label, controlled trial comparing the efficacy and safety of apixaban vs. DAPT after LAAO, both for 3 months. The primary endpoint is a combined endpoint of death, myocardial infarction, stroke, thromboembolic complications, and major or significant bleeding at 3 months of follow-up. Approximately 160 subjects will be enrolled and followed 12 months from randomization.

CONCLUSIONS

Considering the high risk of both thromboembolic and hemorrhagic events of patients undergoing LAAO, establishment of an appropriate antithrombotic therapy in terms of efficacy and safety after LAAO is of vital importance.

TRIAL REGISTRATION

EudraCT number: 2018-001013-32.