WATCHMAN implantation in patients with a history of atrial fibrillation and intracranial hemorrhage

Stroke Prevention in Atrial Fibrillation: Our Current Failures and Required Research

Nonvalvular atrial fibrillation is a common rhythm disorder of middle-aged to older adults that can cause ischemic strokes and systemic embolism. Lifelong use of oral anticoagulants reduces the risk of these ischemic events but increases the risk of major and clinically relevant hemorrhages. These medications also require strict compliance for efficacy, and they have nontrivial failure rates in higher-risk patients. Left atrial appendage closure is a nonpharmacological method to prevent ischemic strokes in atrial fibrillation without the need for lifelong anticoagulant use, but this procedure has the potential for complications and residual embolic events. This workshop of the Roundtable of Academia and Industry for Stroke Prevention discussed future research needed to further decrease the ischemic and hemorrhagic risks among patients with atrial fibrillation. A direct thrombin inhibitor, factor Xa inhibitors, and left atrial appendage closure are FDA-approved approaches whereas factor XIa inhibitors are currently being studied in phase 3 randomized controlled trials for stroke prevention. The benefits, risks, and shortcomings of these treatments and future research required in different high-risk patient populations are reviewed in this consensus statement.

Intracranial bleeding and associated outcomes in atrial fibrillation patients undergoing percutaneous left atrial appendage occlusion: Insights from National Inpatient Sample 2016-2020

Background

Percutaneous left atrial appendage occlusion (LAAO) has proved to be a safer alternative for long-term anticoagulation; however, patients with a history of intracranial bleeding were excluded from large randomized clinical trials.

Objective

The purpose of this study was to determine outcomes in atrial fibrillation (AF) patients with a history of intracranial bleeding undergoing percutaneous LAAO.

Methods

National Inpatient Sample and International Classification of Diseases, Tenth Revision, codes were used to identify patients with AF who underwent LAAO during the years 2016-2020. Patients were stratified based on a history of intracranial bleeding vs not. The outcomes assessed in our study included complications, in-hospital mortality, and resource utilization.

Result

A total of 89,300 LAAO device implantations were studied. Approximately 565 implantations (0.6%) occurred in patients with a history of intracranial bleed. History of intracranial bleeding was associated with a higher prevalence of overall complications and in-patient mortality in crude analysis. In the multivariate model adjusted for potential confounders, intracranial bleeding was found to be independently associated with in-patient mortality (adjusted odds ratio [aOR] 4.27; 95% confidence interval [CI] 1.68-10.82); overall complications (aOR 1.74; 95% CI 1.36-2.24); prolonged length of stay (aOR 2.38; 95% CI 1.95-2.92); and increased cost of hospitalization (aOR 1.28; 95% CI 1.08-1.52) after percutaneous LAAO device implantation.

Conclusion

A history of intracranial bleeding was associated with adverse outcomes after percutaneous LAAO. These data, if proven in a large randomized study, can have important clinical consequences in terms of patient selection for LAAO devices.

Detection and Characterization of Thrombosis in Humans Using Fibrin-Targeted Positron Emission Tomography and Magnetic Resonance

OBJECTIVES

The authors present a novel technique to detect and characterize LAA thrombus in humans using combined positron emission tomography (PET)/cardiac magnetic resonance (CMR) of a fibrin-binding radiotracer, [⁶⁴Cu]FBP8.

BACKGROUND

The detection of thrombus in the left atrial appendage (LAA) is vital in the prevention of stroke and is currently performed using transesophageal echocardiography (TEE).

METHODS

The metabolism and pharmacokinetics of [⁶⁴Cu]FBP8 were studied in 8 healthy volunteers. Patients with atrial fibrillation and recent TEEs of the LAA (positive n = 12, negative n = 12) were injected with [⁶⁴Cu]FBP8 and imaged with PET/CMR, including mapping the longitudinal magnetic relaxation time (T₁) in the LAA.

RESULTS

[⁶⁴Cu]FBP8 was stable to metabolism and was rapidly eliminated. The maximum standardized uptake value (SUV_Max) in the LAA was significantly higher in the TEE-positive than TEE-negative subjects (median of 4.0 [interquartile range (IQR): 3.0-6.0] vs 2.3 [IQR: 2.1-2.5]; P < 0.001), with an area under the receiver-operating characteristic curve of 0.97. An SUV_Max threshold of 2.6 provided a sensitivity of 100% and specificity of 84%. The minimum T₁ (T_1Min) in the LAA was 970 ms (IQR: 780-1,080 ms) vs 1,380 ms (IQR: 1,120-1,620 ms) (TEE positive vs TEE negative; P < 0.05), with some overlap between the groups. Logistic regression using SUV_Max and T_1Min allowed all TEE-positive and TEE-negative subjects to be classified with 100% accuracy.

CONCLUSIONS

PET/CMR of [⁶⁴Cu]FBP8 is able to detect acute as well as older platelet-poor thrombi with excellent accuracy. Furthermore, the integrated PET/CMR approach provides useful information on the biological properties of thrombus such as fibrin and methemoglobin content. (Imaging of LAA Thrombosis; NCT03830320).

Left Atrial Appendage Closure for Patients with Cerebral Amyloid Angiopathy and Atrial Fibrillation: the LAA-CAA Cohort

Anticoagulation increases the risk of intracerebral hemorrhage (ICH) in patients with cerebral amyloid angiopathy (CAA), so the management of stroke-risk in patients with both atrial fibrillation (AF) and CAA is controversial. Advances in left atrial appendage closure (LAAC) techniques provide a stroke-risk-reduction option which avoids long-term oral anticoagulation (OAC). We aimed to evaluate the safety of this intervention in patients with CAA. This is an observational cohort study of patients with severe CAA (with or without ICH) and AF who were treated with LAA closure. The Watchman™ and Amulet® LAAC devices and Lariat procedure or open surgical closure of the LAA were all considered acceptable means of closure. Patients with symptomatic ICH and those naïve to anticoagulation were placed on clopidogrel and/or aspirin for 6 weeks after the procedure; patients who previously tolerated anticoagulation remained on warfarin or a DOAC for 6 weeks post-procedure. All anticoagulation therapy was discontinued after confirmation of LAAC. All patients had aggressively optimized blood pressure and fall precautions in addition to surgical intervention. Safety, tolerability, stroke, and hemorrhage rates were documented. Twenty-six patients with a mean CHA₂DS₂-VASc score of 4.6 were treated, 13 with a history of symptomatic lobar hemorrhage and 13 without. All patients who completed LAAC tolerated the device implantation. There were no documented ischemic strokes or symptomatic ICH during the 30 days after device implantation. Patients were followed for an average of 25 months. One patient who underwent Lariat LAAC had an ischemic stroke in follow-up, but recovered well; there were no other thromboemboli in this cohort. This cohort study provides evidence that LAAC appears to be a safe and tolerable treatment to reduce stroke risk in patients with CAA. Because of the small size of the cohort and relatively short follow-up, the efficacy for stroke and ICH prevention is not conclusive, but the preliminary results are encouraging. LAA closure may be a good alternative to anticoagulation in patients with CAA and atrial fibrillation.