Copyright © 2005, The European Society of Cardiology
Acute mitral valve dysfunction due to leaflet escape in a Tri-technologies bileaflet mechanical valve
aResearchers of the Secretary of Health, Government of the City of Buenos Aires, Argentina
bDepartment of Cardiology, Hospital del Gobierno de la Ciudad de Buenos Aires "Dr. Cosme Argerich", Buenos Aires, Argentina
cDepartment of Cardiovascular Surgery, Hospital del Gobierno de la Ciudad de Buenos Aires "Dr. Cosme Argerich", Buenos Aires, Argentina
Received 7 September 2005; received in revised form 14 November 2005; accepted after revision 4 December 2005.
* Corresponding author. Department of Cardiology, Hospital del Gobierno de la Ciudad de Buenos Aires "Dr. Cosme Argerich", Av. Alte. Brown 240 (/C1155ADP), Buenos Aires, Argentina. Tel.: +54114801 5510; fax: +54114801 4157. tcianciulli{at}fibertel.com.ar
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Abstract |
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Acute prosthetic valve dysfunction due to leaflet escape is a mode of structural valve failure of mechanical prostheses which is associated with a high mortality. In this report, we describe the case of a 32-year-old patient, who underwent mitral valve replacement with a Tri-technologies bileaflet valve three years ago, and was admitted to the hospital on August 2005, in cardiogenic shock. He discontinued oral anticoagulation therapy four months ago. Transthoracic and transesophageal echocardiograms showed acute-onset massive mitral regurgitation with normal left ventricular function. The patient underwent emergency surgery, during which one leaflet was found to be absent and the other leaflet was fixed due to prosthetic thrombus.
Keywords: Leaflet escape; Acute prosthetic valve dysfunction; Tri-technologies
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Introduction |
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Leaflet escape due to fracture of a mechanical valve prosthesis has been previously reported for monoleaflet (Omnicarbon and Björk–Shiley convex–concave valves)1,2 and bileaflet mechanical prostheses (Tekna, Duromedic and Tri-technologies).3–7
Acute prosthetic valve dysfunction is a critical condition which is associated with a high morbidity and mortality rate and requires immediate surgery. Hence, the rapid and exact diagnosis of valve dysfunction is of vital importance.
Delineation of normal prosthetic valve function is often possible with transthoracic echocardiography, but the exclusion of valvular regurgitation is often more difficult than that of valvular stenosis, especially for mechanical prostheses in mitral position, due to the prominent acoustic shadowing that accompanies mechanical prostheses. Consequently, transesophageal echocardiography is the imaging method of choice when the transthoracic echocardiogram is technically inadequate or when borderline findings are detected in the transthoracic echocardiogram of a patient in whom there is a strong clinical suspicion of malfunction.8
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Case report |
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A 32-year-old man with a history of severe mitral and aortic regurgitation due to infective endocarditis, underwent mitral valve replacement with a Tri-technologies bileaflet valve and an aortic valve replacement with a homograft three years ago.
He was admitted to the intensive care unit with cardiogenic shock in August 2005. He had discontinued oral anticoagulation therapy four months ago.
On admission he presented with severe orthopnea, blood pressure was 70/40mmHg in both arms, heart rate was 120 beats/min, and respiratory rate was 25 breaths/min. On pulmonary auscultation, there were rales up to the midscapular region. Cardiac auscultation revealed absence of the valve click and a systolic murmur at the apex.
The chest radiograph showed interstitial pulmonary edema, but no cardiomegaly. The ECG showed sinus tachycardia and left ventricular hypertrophy. Swanz–Ganz catheterization showed a normal mean right atrial pressure (8mmHg), severe elevation of pulmonary capillary wedge pressure (22mmHg), a low cardiac index (2.2l/min/m2) and high systemic and pulmonary vascular resistances (1.178 and 231dyn.sec./cm–5, respectively).
The transthoracic echocardiogram revealed an elevated mean pressure gradient across the mitral valve (15mmHg), normal mean gradient across the aortic valve, no aortic regurgitation, mild left atrial enlargement, normal left ventricular dimensions and a hyperdynamic left ventricular function.
Transesophageal echocardiography (TEE) showed massive mitral regurgitation, extending into the left atrial appendage and into the pulmonary veins (Fig. 1). Continuous-wave Doppler showed a mitral regurgitant jet with a late systolic shoulder due to a rapid rise in left atrial pressure (V wave) and a resulting decrease in transvalvular gradient (Fig. 2). Instead of the typical movement of the bileaflet valve, the TEE showed only one leaflet, fixed in an open position during the whole cardiac cycle (Fig. 3).
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The patient underwent emergency mitral valve replacement. During surgery, the posterior leaflet was not found in the heart, and the anterior leaflet was stuck in an open position, due to a prosthetic thrombus. There was no sign of endocarditis or pannus formation. A 27mm St Jude Medical biological prosthesis was implanted. The abdominal CT scan showed the escaped leaflet in the terminal portion of the aortic bifurcation and the patient had an uneventful recovery. The removal of the embolized disk was deferred, to be performed with lower risk at a later date.
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Discussion |
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Primary structural failure of currently available mechanical valves is extremely rare. Mechanical valve failure has shown to be a limitation of some models of valve prostheses in the past, thus emphasizing the need for rigorous evaluation and testing of all new valves. Examples of mechanical failure in the past with specific valve models that are no longer used include disk embolization from bileaflet tilting-disk valves and strut fracture with certain models of single and double-disk valves.1–3
Minimal information is available regarding the clinical use of the Tri-technologies valve, which has been used in Argentina, Brazil, France, Germany, India, Italy, Spain and Turkey. A review of the relevant literature reveals that most reports of leaflet escape are for valves in the mitral position. This may be due to the strong mechanical forces acting on the valve in this position.
The Tri-technologies prosthetic heart valve (Belo Horizonte, Brazil) is a new low-profile mechanical bileaflet prosthesis made of solid pyrolytic carbon and designed to rotate in situ. The two leaflets open at 85° and are housed in the orifice ring by two tabs that are inserted into orifice hinges.
According to data provided by the Tri-technologies valve manufacturer (Ivan Casagrande, M.D., personal communication, November 18, 2002),7 the overall worldwide incidence of disk escape was nine cases out of 3841 implants (0.23%). It is well known that the true incidence of adverse events reported by the manufacturer is underevaluated since most prosthetic failures are not reported.
In May 2003, Bottio et al.7 reported a high risk of leaflet escape in Tri-technologies prosthetic valves (5.6%/patient-year) as a result of a fracture of the pivoting system, which occurs because the distance between the tabs and the base of the leaflet is asymmetric.
We have previously reported9 that fluoroscopy is a very useful tool in the functional evaluation of prostheses with radiopaque discs; however, it provides no functional information in prostheses with radiolucent discs manufactured in Brazil (Tri-technologies and HP-Biplus) or in valves that are only slightly radiopaque, made in Russia (Jyros). In our Argentinean series of 229 mechanical disc prostheses,9 evaluated with echocardiography, 27 were Tri-technologies prosthetic heart valves, and the implantation failed in three patients (11.1%), because of immediate disc detachment in two cases and post implant rotation in one case. In all these cases, another model of prosthesis was inserted during the same surgical procedure.
In the present case, anticoagulation therapy was discontinued four months ago and was the probable cause of the prosthetic thrombosis involving one of the disks; as to the other disk which escaped from its pivoting point, it is more related to a structural flaw of the prosthesis due to deficiencies in its design.
At present, there are no accepted guidelines about the benefit of preventive replacement of prostheses which are at risk of acute prosthetic failure, and leaflet escape remains a Damocles's sword for patients implanted with such prostheses. Methods for early detection of single leg fracture of the strut in the case of the Björk–Shiley convex–concave heart valve have been based on actively inducing an acoustic vibration or magnetic field and looking at the response, but to our knowledge no practical method has been developed to date.
Thus, the identification of predictors of pivotal fractures becomes crucial for recipients of the Tri-technologies valve worldwide. We are currently unable to identify predictors of prosthetic failure. Fortunately, the reported evidence of structural valve failure has forced the manufacturer to discontinue their distribution. Some authors7 have adopted the policy of performing preventive valve replacement only at the patient's request.
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References |
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- Kornberg A., Wildhirt S.M., Schulze C., Kreuzer E. Leaflet escape in Omnicarbon monoleaflet valve. Eur J Cardiothorac Surg (1999) 15:867–869.
[Abstract/Free Full Text] - Ericsson A., Lindblom D., Semb G., Huysmans H.A., Thulin L.I., Scully H.E., et al. Strut fracture with Bjork–Shiley 70 degrees convexo-concave valve: an international multi-institutional follow-up study. Eur J Cardiothorac Surg (1992) 6:339–346.[Abstract]
- Hemmer W.B., Doss M., Hannekum A., Kapfer X. Leaflet escape in a Tekna and an original Duromedics bileaflet valve. Ann Thorac Surg (2000) 69:942–944.
[Abstract/Free Full Text] - Dikmengil M., Sucu N., Aytacoglu B.N., Mavioglu I. Leaflet escape in a TRI bileaflet rotatable mitral valve. J Heart Valve Dis (2004) 13(4):638–640.[Web of Science][Medline]
- Klepetko W., Moritz A., Mlczoch J., Schurawitzki H., Domanig E., Wolner E. Leaflet fracture in Edwards-Duromedics bileaflet valves. J Thorac Cardiovasc Surg (1989) 97(1):90–94.[Abstract]
- Jazayeri S., Meunier J.P., Tatou E., L'Huillier I., Toulouse C., Bouchot O., Brenot R., et al. Fracture embolization of a Tekna mitral prosthesis: case report. J Heart Valve Dis (2001) 10(2):219–221.[Web of Science][Medline]
- Bottio T., Casarotto D., Thiene G., Caprili L., Angelini A., Gerosa G. Leaflet escape in a new bileaflet mechanical valve TRI technologies. Circulation (2003) 107:2303–2306.
[Abstract/Free Full Text] - Khandheria B.K. Transesophageal echocardiography in the evaluation of prosthetic valves. Cardiol Clin (1993) 11(3):427–436.[Medline]
- Cianciulli T.F., Lax J.A., Beck M.A., Cerruti F.E., Gigena G.E., Saccheri M.C., et al. Cinefluoroscopic assessment of mechanical disc prostheses: its value as a complementary method to echocardiography. J Heart Valve Dis (2005) 14(5):664–673.[Web of Science][Medline]
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