Prosthetic heart valve
Updates to Article Attributes
Prosthetic heart valves are common. The four valves of the heart may all be surgically replaced. However, the aortic and mitral valves are the most commonly replaced.
Replacements may be tissue or metallic valves, only the latter being visualised on imaging investigations. Sometimes the annulus alone is replaced as seen in annuloplasty rings.
In recent times, aortic valves in select circumstances are being replaced via a transcatheter approach, called a transcatheter aortic valve implantation (TAVI) from a femoral artery approach.
Radiographic features
Evaluation of prosthetic valves often relies on multimodality imaging, including transesophageal echocardiography, transthoracic echocardiography, fluoroscopy, and computed tomography (CT) 3.
Echocardiography
Valve appearance on echocardiography is dependent on the type of valve, which are generally subdivided into two categories (mechanical and bioprosthetic) with examples as follows 4,5:
- mechanical valves
- ball cage valves
- Starr-Edwards caged ball valve
- tilting disk valves
- Bjork-Shiley tilting disk valve
- ball cage valves
- bioprosthetic valves
- homografts
- heterografts
- stented
- Carpentier-Edwards stented aortic valve
- stentless
- Biocor stentless aortic valve
Transesophageal echocardiography is the modality of choice to assess the status of a prosthetic heart valve; a baseline study is typically performed after placement, and subsequent studies rely on comparison with this baseline to assess for pathology.
Complications of prosthetic valves 5:
- obstruction
- may be due to thrombus or pannus 4
-
may requireCan be differentiated on MDCTto discriminate based onattenuationdifferences-
:
- Pannus appears as a circular or semicircular mass extending from the prosthesis ring. Thrombus appear as an irregular lobulated mass.
-
pannusPannus can demonstrate enhancement. - Pannus typically has a significantly higher attenuation, as measured by Hounsfield units (HU). A cut-off point of >145 HU has been recommended (sensitivity 88%, specificity 96%).
-
- thrombogenic obstruction typically occurs with a subtherapeutic INR early after mechanical prosthesis implantation 6
- typically occult to transthoracic studies
- the posterior acoustic shadowing from the valve obscures the typical atrial location of thrombi
- obstruction due to pannus tends to be a more chronic process, with a slow symptom onset and older valvular prosthesis
- may be due to thrombus or pannus 4
- with or without paravalvular abscess
- mechanical failure in mechanical valves
- degeneration of a biological valve
Severe dysfunction of a prosthetic valve should be suspected when the following parameters are measured 5:
-
mitral valve
- severe regurgitation
- vena contracta (VC) >0.6 cm
- dense, triangular continuous wave Doppler envelope with early peak
- systolic flow reversal on pulmonary venous Doppler
- severe stenosis
- mitral inflow velocity peak >2.5 m/s
- pressure half time >200 ms
- severe regurgitation
-
aortic valve
- severe stenosis
- peak outflow velocity >4 m/s
- a ratio of the aortic velocity time integral (VTI) to the left ventricular outflow tract (LVOT) VTI less than 0.25
- severe regurgitation
- doppler studies of the descending aorta show holodiastolic flow reversal
- regurgitant jet fills more than 65% of the LVOT
- severe stenosis
See also
-<p><strong>Prosthetic heart valves </strong>are common. The four valves of the heart may all be surgically replaced. However, the <a href="/articles/aortic-valve">aortic</a> and <a href="/articles/mitral-valve">mitral valves</a> are the most commonly replaced.</p><p>Replacements may be tissue or metallic valves, only the latter being visualised on imaging investigations. Sometimes the annulus alone is replaced as seen in <a href="/articles/annuloplasty-rings">annuloplasty rings</a>.</p><p>In recent times, aortic valves in select circumstances are being replaced via a transcatheter approach, called a <a href="/articles/transcatheter-aortic-valve-implantation-tavi-2">transcatheter aortic valve implantation (TAVI)</a> from a femoral artery approach.</p><h4>Radiographic features</h4><p>Evaluation of prosthetic valves often relies on multimodality imaging, including transesophageal echocardiography, transthoracic echocardiography, fluoroscopy, and <a href="/articles/computed-tomography">computed tomography (CT)</a> <sup>3</sup>.</p><h5>Echocardiography</h5><p>Valve appearance on <a href="/articles/transthoracic-echocardiography-views">echocardiography</a> is dependent on the type of valve, which are generally subdivided into two categories (mechanical and bioprosthetic) with examples as follows <sup>5</sup>:</p><ul>- +<p><strong>Prosthetic heart valves </strong>are common. The four valves of the heart may all be surgically replaced. However, the <a href="/articles/aortic-valve">aortic</a> and <a href="/articles/mitral-valve">mitral valves</a> are the most commonly replaced.</p><p>Replacements may be tissue or metallic valves, only the latter being visualised on imaging investigations. Sometimes the annulus alone is replaced as seen in <a href="/articles/annuloplasty-rings">annuloplasty rings</a>.</p><p>In recent times, aortic valves in select circumstances are being replaced via a transcatheter approach, called a <a href="/articles/transcatheter-aortic-valve-implantation-tavi-2">transcatheter aortic valve implantation (TAVI)</a> from a femoral artery approach.</p><h4>Radiographic features</h4><p>Evaluation of prosthetic valves often relies on multimodality imaging, including transesophageal echocardiography, transthoracic echocardiography, fluoroscopy, and <a href="/articles/computed-tomography">computed tomography (CT)</a> <sup>3</sup>.</p><h5>Echocardiography</h5><p>Valve appearance on <a href="/articles/transthoracic-echocardiography-views">echocardiography</a> is dependent on the type of valve, which are generally subdivided into two categories (mechanical and bioprosthetic) with examples as follows <sup>4,</sup><sup>5</sup>:</p><ul>
-<li>may require <a href="/articles/computed-tomography">MDCT</a> to discriminate based on <a href="/articles/attenuation-coefficient">attenuation </a>differences<ul><li>pannus typically has a significantly higher attenuation, as measured by <a href="/articles/hounsfield-unit">Hounsfield units (HU)</a>-</li></ul>- +<li>Can be differentiated on <a href="/articles/computed-tomography">MDCT</a>:<ul>
- +<li>Pannus appears as a circular or semicircular mass extending from the prosthesis ring. Thrombus appear as an irregular lobulated mass.</li>
- +<li>Pannus can demonstrate enhancement.</li>
- +<li>Pannus typically has a significantly higher attenuation, as measured by <a href="/articles/hounsfield-unit">Hounsfield units (HU)</a>. A cut-off point of >145 HU has been recommended (sensitivity 88%, specificity 96%).</li>
- +</ul>
-<li>thrombogenic obstruction typically occurs with a subtherapeutic <a title="INR" href="/articles/inr">INR</a> early after mechanical prosthesis implantation <sup>6</sup><ul>- +<li>thrombogenic obstruction typically occurs with a subtherapeutic <a href="/articles/inr">INR</a> early after mechanical prosthesis implantation <sup>6</sup><ul>
-<a title="Haemolytic anaemia" href="/articles/haemolytic-anaemia">haemolytic anaemia</a>: rare, both biological and mechanical valves <sup>7</sup>- +<a href="/articles/haemolytic-anaemia">haemolytic anaemia</a>: rare, both biological and mechanical valves <sup>7</sup>
-</ul><h4>See also</h4><ul><li><a title="Transcatheter aortic valve implantation (TAVI)" href="/articles/transcatheter-aortic-valve-implantation-tavi-2">transcatheter aortic valve implantation (TAVI)</a></li></ul>- +</ul><h4>See also</h4><ul><li><a href="/articles/transcatheter-aortic-valve-implantation-tavi-2">transcatheter aortic valve implantation (TAVI)</a></li></ul>
References changed:
- 7. Maraj R, Jacobs L, Ioli A, Kotler M. Evaluation of Hemolysis in Patients with Prosthetic Heart Valves. Clin Cardiol. 1998;21(6):387-92. <a href="https://doi.org/10.1002/clc.4960210604">doi:10.1002/clc.4960210604</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/9631266">Pubmed</a>
- 4. Dangas GD, Weitz JI, Giustino G, Makkar R, Mehran R. Prosthetic Heart Valve Thrombosis. (2016) Journal of the American College of Cardiology. 68 (24): 2670-2689. <a href="https://doi.org/10.1016/j.jacc.2016.09.958">doi:10.1016/j.jacc.2016.09.958</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/27978952">Pubmed</a> <span class="ref_v4"></span>