人工二尖瓣膜伴局部血栓
A 63-year-old woman presented for evaluation after 2 weeks of progressive dyspnea. She had a history of dilated cardiomyopathy, and a St. Jude prosthetic valve had been inserted in the mitral position 6 years earlier for mitral insufficiency. Since then she had been taking a maintenance dose of warfarin. The physical examination was notable for bibasilar crackles and a muffled S1 heart sound. The international normalized ratio was subtherapeutic at 2.0 (target range, 2.5 to 3.5). Fluoroscopy of the prosthetic mitral valve showed that one of the leaflets was stuck in the closed position (Video 1). Transesophageal echocardiography confirmed the presence of one immobile leaflet and showed an elevated transvalvular gradient (11.6 mm Hg) (Panel A, arrow) and a large thrombus in the left atrial appendage (Panel B, arrow). After continuous infusion of streptokinase for 72 hours, examination revealed the return of a metallic S1 heart sound, and fluoroscopy showed normal movement of the bileaflet St. Jude valve (Video 2). There was no evidence of embolic complications or bleeding. The patient had marked alleviation of her dyspnea. She continues to do well with warfarin and aspirin, and there has been no further dysfunction of the prosthetic valve.
Information
© 2009 Nucleus Medical Art, Inc.
| Table 1 | |||
| Quantitative echocardiographic parameters of valvular lesions | |||
| Mitral regurgitation | |||
| Regurgitant fraction (%) |
Effective regurgitant orifice (mm2) |
||
| Mild | <30 | <20 | |
| Moderate | 30-39 | 20-29 | |
| Moderately severe | 40-49 | 30-39 | |
| Severe | ≥50 | ≥40 | |
| Aortic stenosis * | |||
| Mean gradient (mm Hg) |
Peak velocity (m/sec) |
Area (cm2) |
|
| Mild | <25 | <3.5 | >1.0 |
| Moderate | 25-50 | 3.5-4.5 | 0.76-1.0 |
| Severe | >50 | >4.5 | <0.76 |
| Mitral stenosis | |||
| Mean gradient (mm Hg) |
Area (cm2) |
||
| Mild | <5 | >1.5 | |
| Moderate | 5-10 | 1.0-1.5 | |
| Severe | >10 | <1.0 | |
Causes
Prosthetic heart valve thrombosis is thought to result from an interaction between components of blood and the prosthesis or turbulent blood flow in and around the prosthesis.
Risk Factors
The following factors may increase your chance of developing prosthetic heart valve thrombosis. If you have any of the following risk factors, tell your doctor:
* Inadequate anticoagulant therapy after a valve transplant
* Prosthesis located at the mitral valve in the heart
* Atrial fibrillation
* Drugs (eg, contraceptives)
* Cancerous tumors
* Systemic diseases (eg, systemic lupus erythematosus, inflammation and damage to various body tissues, including joints, skin, kidneys, heart, lungs, blood vessels, and brain)
* Reduced cardiac pumping (low ejection fraction)
Symptoms
* Shortness of breath
* Difficulty breathing while lying down
* Waking at night short of breath
* Swelling
* Fatigue
* Difficulty exercising
* Chest pain, burning, or pressure
* Nausea
* Numbness
* Loss of consciousness
* Stroke
* Transient ischemic attack
* Absence or lessening of prosthetic noise
Diagnosis
Your doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include the following:
* Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
* Blood tests
* Fluoroscopy—an x-ray technique
Treatment
Talk with your doctor about the best treatment plan for you. Treatment options include:
Thrombolysis
The first line of therapy is usually thrombolysis, which uses medications to break up abnormal blood clots.
Anticoagulation Therapy
Anticoagulant medications are used to control clotting. Anticoagulation therapy may be used alone in people with small clots that are not obstructing the heart valve.
Valve Replacement
In some cases, surgery to replace the valve may be necessary.
reference
http://content.nejm.org/cgi/content/full/357/4/349
https://healthlibrary.epnet.com/GetContent.aspx?token=c5987b1e-add7-403a-b817-b3efe6109265chunkiid=90822&chunkiid=191350
http://www.fac.org.ar/qcvc/llave/c139i/cardar.php
http://cmbi.bjmu.edu.cn/uptodate/Valvular%20and%20aortic%20disease/Prosthetic%20valves/Management%20of%20patients%20with%20prosthetic%20heart%20valves.htm
http://www.med.yale.edu/intmed/cardio/echo_atlas/contents/index.html
