Related Experiment Videos
Antithrombotic therapy in patients with valvular heart disease and prosthetic heart valves
Insights
Antithrombotic therapy prevents thromboembolism in valvular heart disease and prosthetic valves. Recommendations cover mechanical and bioprosthetic valves, with specific guidance for atrial fibrillation and post-operative care.
Area of Science:
- Cardiology
- Vascular Medicine
- Pharmacology
Background:
- Thromboembolism poses a significant risk in patients with valvular heart disease and prosthetic heart valves.
- Antithrombotic therapy is crucial for preventing adverse events in these patient populations.
- Clinical guidelines for antithrombotic management require clear evidence-based recommendations.
Purpose of the Study:
- To discuss indications for antithrombotic therapy in valvular heart disease and prosthetic heart valves.
- To describe and grade the evidence supporting clinical recommendations for antithrombotic therapy.
- To outline specific antithrombotic strategies for mechanical and bioprosthetic valves, including special situations.
Main Methods:
- Review of clinical evidence for antithrombotic therapy recommendations.
- Grading of evidence into five levels.
- Discussion of risk factors for thromboembolism in prosthetic heart valve patients.
- Consideration of special circumstances like pregnancy and surgery.
Main Results:
- Indications for anticoagulation in valvular heart disease include atrial fibrillation, large left atrium, heart failure, or prior thromboembolism.
- Therapy aims for a target international normalized ratio (INR) of 3.0-4.5.
- For mechanical valves, indefinite oral anticoagulation plus dipyridamole is recommended; platelet inhibitors alone are insufficient.
- For bioprosthetic valves, duration of anticoagulation varies based on valve type and patient factors; aspirin may be used post-aortic valve replacement.
Conclusions:
- Antithrombotic therapy requires tailored approaches based on valvular heart disease type, prosthetic valve type, and patient-specific risk factors.
- Evidence grading helps inform clinical decision-making for antithrombotic management.
- Specific protocols exist for managing antithrombotic therapy in mechanical and bioprosthetic valves, as well as in special clinical scenarios.
Abstract:
Indications and the type of antithrombotic therapy for the prevention of thromboembolism in patients with valvular heart disease, mechanical prosthetic heart valves and bioprosthetic heart valves are discussed. The evidence for these clinical recommendations is described and graded into five levels. The indications for anticoagulation in patients with valvular heart disease are chronic or paroxysmal atrial fibrillation, sinus rhythm with a very large left atrium, severe left ventricular dysfunction or presence of heart failure or a history of previous thromboembolism. Anticoagulant therapy is administered to prolong the prothrombin time to 1.5 to 2.0 times control, using rabbit brain thromboplastin (standardized international normalized ratio = 3.0 to 4.5). Risk factors for thromboembolism in patients with prosthetic heart valves are discussed. Because intracardiac thrombus formation may start during and continues early after operation, restarting heparin therapy 6 hours after operation and continuing it for the duration of the hospitalization is advised. For mechanical prosthetic heart valves, oral anticoagulation as outlined plus dipyridamole is advised indefinitely. Platelet inhibitor therapy alone is insufficient. For bioprosthetic heart valves, heparin is followed by oral anticoagulation as outlined for 3 months after mitral or aortic valve replacement and indefinitely after mitral valve replacement if there is atrial fibrillation or a very large left atrium; aspirin may be recommended indefinitely after aortic valve replacement. Antithrombotic therapy is also considered for four special situations: noncardiac surgery, prosthetic valve endocarditis, anticoagulation after a thromboembolic event, and antithrombotic therapy during pregnancy.