Mechanical Valve and Atrial Fibrillation

Every mechanical valve is a highly thrombogenic material; therefore, every patient, regardless of the presence of atrial fibrillation (AF), must take anticoagulant therapy—specifically Warfarin (not NOAC).

Warfarin is more effective because it blocks the coagulation cascade at four levels.

NOAC block the coagulation cascade at only one level.

Approximately 0.01% of the population has a mechanical valve.

AF occurs in 30–40% of patients with a mechanical valve.

The risk of mechanical valve thrombosis after discontinuation of Warfarin gradually increases up to 20–40% per year.

Prosthetic valves are divided into:

Mechanical (special metal and synthetic material)
Bioprosthetic (from pig or cow)

The main advantage of a mechanical valve compared with a bioprosthetic valve is

that the mechanical valve lasts longer, but the patient must take Warfarin lifelong.

Mechanical valve:

Durability 20–30 years
Preferred in younger patients
Highly thrombogenic material
Requires lifelong Warfarin therapy, regardless of AF

Bioprosthetic valve:

Durability 10–15 years
Preferred in older patients
Requires Warfarin for the first 3 months after implantation
If the patient has AF, then after 3 months, according to the CHA₂DS₂-VA score

anticoagulant therapy is indicated; NOAC are preferred.

Illustration of valvular atrial fibrillation in a patient with a mechanical heart valve, showing an ECG recording of atrial fibrillation and indication for anticoagulation with warfarin.

Anticoagulant Therapy and Mechanical Valve	Class
In patients with atrial fibrillation (AF) and a mechanical valve (valvular AF), Warfarin is always indicated, regardless of the CHA₂DS₂-VA score.	I
In patients with AF after implantation of a bioprosthetic valve, Warfarin is indicated for the first 3 months; thereafter, anticoagulant therapy (NOAC or Warfarin) is indicated according to the CHA₂DS₂-VA score.	I