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

Pharmacogenomic Considerations for Anticoagulant Prescription in Patients with Hereditary Haemorrhagic Telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is a vascular dysplasia that commonly results in bleeding but with frequent indications for therapeutic anticoagulation. Our aims were to advance the understanding of drug-specific intolerance and evaluate if there was an indication for pharmacogenomic testing. Genes encoding proteins involved in the absorption, distribution, metabolism, and excretion of warfarin, heparin, and direct oral anticoagulants (DOACs) apixaban, rivaroxaban, edoxaban, and dabigatran were identified and examined. Linkage disequilibrium with HHT genes was excluded, before variants within these genes were examined following whole genome sequencing of general and HHT populations. The 44 genes identified included 5/17 actionable pharmacogenes with guidelines. The 76,156 participants in the Genome Aggregation Database v3.1.2 had 28,446 variants, including 9668 missense substitutions and 1076 predicted loss-of-function (frameshift, nonsense, and consensus splice site) variants, i.e., approximately 1 in 7.9 individuals had a missense substitution, and 1 in 71 had a loss-of-function variant. Focusing on the 17 genes relevant to usually preferred DOACs, similar variant profiles were identified in HHT patients. With HHT patients at particular risk of haemorrhage when undergoing anticoagulant treatment, we explore how pre-emptive pharmacogenomic testing, alongside HHT gene testing, may prove beneficial in reducing the risk of bleeding and conclude that HHT patients are well placed to be at the vanguard of personalised prescribing.

Antithrombotic therapy for atrial fibrillation in hereditary hemorrhagic telangiectasia

Antithrombotic therapy reduces stroke risk in patients with atrial fibrillation but at the cost of increased bleeding risk. Patients with hereditary hemorrhagic telangiectasia (HHT) are at increased bleeding risk due to fragile mucocutaneous telangiectasias and visceral arteriovenous malformations. These patients are simultaneously at elevated thrombotic risk due to the vascular abnormalities of HHT. Managing atrial fibrillation in patients with HHT represents an understudied and challenging clinical scenario. We present a retrospective cohort study investigating antithrombotic therapy in patients with HHT and atrial fibrillation. We found that antithrombotic therapy was poorly tolerated, leading to premature dose-reduction or discontinuation of therapy in a majority of patients and in a majority of treatment episodes. Five patients undergoing left atrial appendage procedures did well despite difficulties completing the prescribed course of post-procedure antithrombotic therapy. Left atrial appendage occlusion or simultaneous administration of systemic anti-angiogenic therapy may represent alternatives but require additional study in patients with HHT.

Anticoagulation and antiplatelet therapy in hereditary hemorrhagic telangiectasia: A scoping review

INTRODUCTION

Data describing safety and tolerability of anticoagulation and antiplatelet therapy in hereditary hemorrhagic telangiectasia (HHT), the second-most-common inherited bleeding disorder, is limited.

METHODS

We performed a scoping review, searching MEDLINE and EMBASE from inception to March 2023 for eligible studies reporting detailed clinical data describing antithrombotic use in HHT. Data extracted included study design, patient population, and characteristics and outcomes of antithrombotic therapy.

RESULTS

Of 625 unique manuscripts identified through database search, 77 were included: 64 case reports/case series describing 65 patients and 13 cohort studies. Data were extracted on a total of 466 patients with HHT, covering 587 episodes of antithrombotic therapy. The most common reasons for antithrombotic therapy were venous thromboembolism (VTE) (44.6 %), atrial arrhythmias (17.8 %) and stroke (10.5 %). anticoagulation was used in in 356 episodes (61.9 %), antiplatelet therapy in 140 episodes (24.3 %), and both together in 50 episodes (8.7 %). Complications of therapy included worsened HHT-associated bleeding (primarily epistaxis and gastrointestinal bleeding) in 198 antithrombotic treatment episodes (38.9 %) and premature antithrombotic therapy discontinuation in 142 episodes (28.9 %). Bleeding-directed therapy (local ablative therapy and systemic therapies) were employed to address worsening bleeding in 14.6 % of episodes. No specific complications of therapy were reported in 322 total antithrombotic events (58.4 %). Rates of bleeding (8.3 % to 80 %), therapy discontinuation (14.3 % to 57.1 %), and other complications ranged considerably from study to study.

CONCLUSION

Current publications vary widely on the outcomes and tolerability of antithrombotics in HHT, but confirm the clinical challenge of adequate antithrombotic therapy in this population. More formal studies are needed to better guide optimal antithrombotic use in HHT.

Percutaneous left atrial appendage closure: beyond the classic indications

Percutaneous left atrial appendage closure (LAAC) has proven to be an effective alternative to oral anticoagulation (OAC) for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). International guidelines traditionally recommend LAAC for NVAF patients at high thromboembolic risk and contraindication to or at high risk for OAC. However, there are many other clinical situations in which this procedure may also be beneficial. This paper discusses the potential role of LAAC in specific haemorrhagic diseases (cerebral amyloid angiopathy, age-related macular degeneration, hereditary haemorrhagic telangiectasia, and Moyamoya disease), after left atrial appendage (LAA) electrical isolation, in cases of persistent thrombus inside the LAA, in end-stage renal disease and in special groups of patients for whom low compliance and persistence to OAC may be anticipated.

MitraClip™ implantation plus left atrial appendage occlusion in a hereditary hemorrhagic telangiectasia patient

Hereditary hemorrhagic telangiectasia is regarded as a high hemorrhagic risk condition, and the management of anticoagulation and heart surgery in these patients can be challenging. The authors describe a combined percutaneous treatment of mitral regurgitation and left atrial appendage occlusion in a patient affected by hereditary hemorrhagic telangiectasia and atrial fibrillation, supporting the safety and feasibility of the procedure and the optimal short-term outcome.