Prosthetic Heart Valves Workup

  • Author: Eric M Kardon, MD, FACEP; Chief Editor: David FM Brown, MD   more...
 
Updated: Feb 8, 2010
 

Laboratory Studies

  • Complete blood count
    • Hemolysis may cause anemia. In this case, microscopic evidence of hemolysis should be present. A sudden increase in hemolysis may signal a perivalvular leak.[6]
    • A hematocrit lower than 34% is present in 74% of patients with PVE and is the most common hematologic finding.
    • A WBC count lower than 12,000 is present in as many as 54% of patients with PVE.
  • Urinalysis: Hematuria is present in 57% of patients with PVE.
  • Blood cultures
    • Culture results are positive in multiple samples in 97% of patients with PVE.
    • Blood cultures should be held for 3 weeks.
    • Multiple blood cultures should be taken.
  • Prothrombin time (PT)/international normalized ratio (INR): Recommendations vary as to the target INR. The following is offered as a general guideline, but remember that therapy must be individualized.
    • Bioprosthetic valves: INR 2-3 for 3 months following implantation; anticoagulation may then be discontinued unless the patient has another indication, such as atrial fibrillation or development of prosthetic valve thrombosis.
    • Mechanical valves: INR 2.5-3.5; patients with atrial fibrillation and those with valves in the mitral position should be kept at the higher end of this range. Patients with bileaflet valves may be kept at the lower end of this range.
    • Nontherapeutic values should raise the suspicion of valve thrombosis or systemic embolization.
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Imaging Studies

  • An overpenetrated anteroposterior chest radiograph helps to delineate the valvular morphology and whether or not the valve and occluder are intact. In more stable patients, a lateral chest film helps identify the valve position and type.
  • The following are descriptions of the radiographic appearance of the more commonly seen valves. For a more comprehensive algorithmic approach to radiographic identification, see the article by Mehlman (1988).[7]
    • Starr-Edwards caged ball valve
      • Radiopaque base ring
      • Radiopaque cage
      • Three struts for the aortic valve; 4 struts for the mitral or tricuspid valve
      • Silastic ball impregnated with barium that is mildly radiopaque (but not in all models)
    • Bjork-Shiley tilting disc valve (discontinued, but many patients still have these valves implanted)
      • Base ring and struts are radiopaque.
      • Two U-shaped struts project into base ring.
      • Edge of occluder disc is also radiopaque.
    • Medtronic-Hall tilting disc valve
      • Radiopaque base ring
      • Radiopaque struts that project into base ring: 3 small ones and 1 large hook-shaped one
      • Occluder disc that is mildly opaque but often cannot be seen
    • Alliance Monostrut valve
      • Occluder has a radiopaque rim.
      • The base ring and two struts are radiopaque.
    • St. Jude medical bileaflet valve
      • Mildly radiopaque leaflets are best seen when viewed on end. Seen as radiopaque lines when the leaflets are fully open.
      • Base ring is not visualized on most models.
      • The valve may not be visualized on some radiographs.
    • CarboMedics bileaflet valves: Valve housing and leaflets are radiopaque and easily visible.
    • Carpentier-Edwards porcine valve: The tall serpiginous wire support is the only visualized portion.
    • Hancock porcine valve
      • The radiopaque base ring is the only visible part in some models.
      • Other models have radiopaque stent markers with or without a visible base ring.
    • Ionescu-Shiley bovine pericardial valve: Base ring and wide fenestrated stents are one piece.
  • Echocardiography
    • Acoustic shadowing originating from the components of the prosthetic valve can severely limit the image of the valve itself as well as any pathologic process such as regurgitant streams, vegetations, and thrombosis. This is especially true with valves in the mitral position.
    • Two-dimensional and Doppler echocardiography, while not as reliable, may demonstrate perivalvular leaks, vegetations, and inadequate valve/occluder movement.
    • Two-dimensional echocardiography and Doppler echocardiography can detect the presence of acute valvular regurgitation and grade the severity.
    • Transesophageal echocardiography has emerged as the imaging study of choice in patients with a suspected prosthetic valve complication. This applies especially to prosthetic mitral valves, where transthoracic Doppler is often insensitive. Adequately excluding prosthetic valve regurgitation with a transthoracic echocardiogram is difficult.
    • In cases where any significant suspicion of valvular stenosis or regurgitation exists, an unremarkable transthoracic echocardiogram is unlikely to be sufficient to adequately rule out a pathologic process.
  • Cinefluorography may detect impaired occluder movement but often cannot readily determine the etiology.
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Other Tests

  • Electrocardiography
    • An atrioventricular (AV) block may indicate the presence of a myocardial abscess. A fever and new AV block is considered PVE until proven otherwise.
    • Atrial fibrillation is common in mitral valve replacement and may cause hemodynamic compromise.
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Procedures

  • Certain procedures may cause bacteremia and thereby increase the chance of PVE. The emergency physician must be up to date with the latest prophylaxis guidelines. See Deterrence/Prevention.
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Proceed to Treatment & Management
 
 
Contributor Information and Disclosures
Author

Eric M Kardon, MD, FACEP  Attending Emergency Physician, Georgia Emergency Medicine Specialists; Physician, Division of Emergency Medicine, Athens Regional Medical Center

Eric M Kardon, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

A Antoine Kazzi  MD, Deputy Chief of Staff, American University of Beirut Medical Center; Associate Professor, Department of Emergency Medicine, American University of Beirut, Lebanon

A Antoine Kazzi is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

David FM Brown, MD  Associate Professor, Division of Emergency Medicine, Harvard Medical School; Vice Chair, Department of Emergency Medicine, Massachusetts General Hospital

David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

References

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  2. Habib G, Thuny F, Avierinos JF. Prosthetic valve endocarditis: current approach and therapeutic options. Prog Cardiovasc Dis. Jan-Feb 2008;50(4):274-81. [Medline].

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  4. Daniels PR, McBane RD, Litin SC, Ward SA, Hodge DO, Dowling NF, et al. Peri-procedural anticoagulation management of mechanical prosthetic heart valve patients. Thromb Res. Feb 19 2009;[Medline].

  5. Botta L, Bechan R, Yilmaz A, Di Bartolomeo R. Prosthetic valve endocarditis due to Brucella: successful outcome with a combined strategy. J Cardiovasc Med (Hagerstown). Mar 2009;10(3):257-8. [Medline].

  6. Shapira Y, Vaturi M, Sagie A. Hemolysis associated with prosthetic heart valves: a review. Cardiol Rev. May-Jun 2009;17(3):121-4. [Medline].

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  9. [Guideline] Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. Oct 9 2007;116(15):1736-54. [Medline].

  10. [Guideline] Horstkotte D, Follath F, Gutschik E, Lengyel M, Oto A, Pavie A, et al. Guidelines on prevention, diagnosis and treatment of infective endocarditis. The Task Force on Infective Endocarditis of the European Society of Cardiology. France: European Society of Cardiology. 2004;[Full Text].

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Medtronic Hall mitral valve. Reproduced with permission from Medtronic, Inc.
The Hancock M.O. II aortic bioprosthesis (porcine). Reproduced with permission from Medtronic, Inc.
Starr-Edwards Silastic ball valve mitral Model 6120. Reproduced with permission from Baxter International, Inc.
Carpentier-Edwards Duralex mitral bioprosthesis (porcine). Reproduced with permission from Baxter International, Inc.
Carpentier-Edwards Perimount pericardial aortic bioprosthesis. Reproduced with permission from Baxter International, Inc.
St. Jude Medical mechanical heart valve. Photograph courtesy of St. Jude Medical, Inc. All rights reserved. St. Jude Medical is a registered trademark of St. Jude Medical, Inc.
 
 
 
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