Apixaban for the Prevention of Latent Biological Valve Thrombosis

Summary

Background: The optimal antithrombotic strategy early after aortic valve replacement surgery with a biological valve remains controversial due to lack of high-quality evidence. Either oral anticoagulants or acetylsalicylic acid should be considered for the first three months. Hypo-attenuated leaflet thickening on cardiac compute tomography has been associated with latent bioprosthetic valve thrombosis and may be prevented with anticoagulation. The investigators hypothesize that anticoagulation with apixaban is superior to single antiplatelet therapy with acetylsalicylic acid in reduction of hypo-attenuated leaflet thickening of bioprosthetic valves after aortic valve replacement.

Methods: In this prospective, open-label, randomized trial patients without an indication for oral anticoagulation undergoing isolated aortic valve replacement surgery with novel rapid-deployment bioprosthetic valves will be randomized. The treatment group will receive 5 mg of apixaban twice a day for the first three months and 100 mg of acetylsalicylic acid thereafter. The control group will have 100 mg of acetylsalicylic acid once a day indefinitely. After the three-month treatment period a contrast enhanced electrocardiogram-gated cardiac computed tomography will be performed to identify hypo-attenuated leaflet thickening of the bioprosthetic valve. The primary objective of the study is to assess possible superiority of the treatment group in the prevention of hypo-attenuated leaflet thickening three months after randomization. Secondary objective is to assess possible noninferiority for safety of apixaban-based strategy when compared to acetylsalicylic acid at three months.

Discussion: Antithrombotic therapy after aortic valve replacement surgery is used to prevent valve thrombosis and systemic thromboembolism. Latent bioprosthetic valve thrombosis is a precursor of clinically significant prosthetic valve dysfunction or thromboembolic event. The hallmark feature of latent bioprosthetic valve thrombosis is hypo-attenuated leaflet thickening on cardiac computed tomography. Subclinical leaflet thrombosis occurs frequently in bioprosthetic aortic valves, more commonly in transcatheter than in surgical valves. There is no evidence on the effect of direct oral anticoagulants on the incidence of hypo-attenuated leaflet thickening after surgical aortic valve replacement with rapid deployment bioprostheses.

Conditions

• Aortic Valve Replacement
• Antithrombotic Therapy
• Bioprosthetic Valve Thrombosis
• Rapid Deployment Valves

Interventions

PROCEDURE

Aortic valve replacement surgery

Patients undergoing first-time isolated aortic valve replacement with a rapid deployment biological prosthesis.

DIAGNOSTIC_TEST

Computed tomography

All the study patients will undergo a computed tomography imaging to assess for hypo-attenuated leaflet thickening and reduced leaflet mobility of the biological prosthesis following the three-month treatment period.

DIAGNOSTIC_TEST

Echocardiography

All the study patients will undergo a transthoracic echocardiography before hospital discharge and following the three-month treatment period.

Sponsors & Collaborators

• Clinical Hospital Centre Zagreb

  lead OTHER

Principal Investigators

• Tomislav Kopjar, MD, PhD · Clinical Hospital Centre Zagreb

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-12-31

Primary Completion

2025-12-31

Completion

2025-12-31

Countries

• Croatia

Study Locations