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J Thorac Cardiovasc Surg 2007;134:1344-1345
© 2007 The American Association for Thoracic Surgery
Brief Communication |
Department of Cardiac Surgery, Albertinen-Krankenhaus, Hamburg, Germany.
Received for publication June 12, 2007; accepted for publication July 5, 2007. * Address for reprints: Lorenz Hansen, MD, Department of Cardiac Surgery, Albertinen-Krankenhaus, Hamburg 22457, Germany. (Email: lorenz.hansen{at}albertinen.de).
A 57-year-old patient received a 27-mm Medtronic Advantage aortic valve prosthesis (Medtronic, Inc, Minneapolis, Minn) for a combined aortic valve lesion. The valve was implanted with pledget-supported noneverting mattress sutures. The axis of the valve’s central opening was oriented toward the commissure between the left and right coronary cusps. After implantation, leaflet function was tested with a valve tester supplied by the manufacturer. No tissue of the native aortic annulus or suture material could be identified through the valve orifice. The valve was not rotated. A predischarge echocardiogram showed a normally functioning prosthesis with physiologic washing jets in the hinge area, a maximal pressure gradient of 14 mm Hg, and an aortic valve area of 2.68 cm2.
Nine weeks postoperatively, the patient returned with dyspnea on exertion. An echocardiogram showed an every-beat aortic regurgitation grade II–III with two regurgitant jets, one of which was considered paravalvular. On reoperation, no sign of paravalvular leakage could be detected. The suture ring of the prosthesis was covered with fresh endothelium. There was no clinical sign of endocarditis, and swab testing showed no organism. The complete valve, with particular regard to the leaflet hinges, was free of thrombus. There was no pannus formation or interference with suture material. In situ testing showed that the valve insufficiency was caused by incomplete closure of the anterior leaflet opposite the right coronary ostium. By applying gentle pressure to the leaflet, we were able to achieve a complete closure of the valve. Distinct leaflet interference was noticed in the valve hinge under the commissure between the left and right coronary cusps. This finding was reproducible. The explanted valve was returned to the manufacturer for further investigation.
Eichinger and associates1
reported occasional single-beat regurgitation of varying intensity with the Medtronic Advantage aortic valve after a mean follow-up of 26.2 months in 5 of 61 patients. Fluoroscopy revealed asymmetric closure that either of the two leaflets in the same prosthesis could affect.
Intermittent single-beat regurgitation has led to reoperations and a valve replacement being reported to the Food and Drug Administration in 2005. Even though a moderate grade of regurgitation with a recordable drop in diastolic blood pressure could be recorded and regurgitation occurred with a frequency of up to 30 times per minute, patients with occasional single-beat regurgitation are clinically asymptomatic. Surveillance for this type of valve dysfunction is indicated.
In the case of the explanted valve, regurgitation was continuous and the patient became symptomatic. Inasmuch as the dysfunction was related to a single leaflet and apparently to a single hinge, we classify this event as a structural failure. To our knowledge, this is the first case of structural valve failure observed with the Medtronic Advantage aortic valve.
Further implantation of the Advantage heart valve has been suspended at our department.
A review of the production records by the manufacturer showed that the implanted valve fulfilled the quality specifications, with an opening angle slightly larger than 86°. On re-examination of the explant, this angle exceeded 90°. A leaflet overlap was noticed. Because the valve showed a normal function directly postoperatively, a wearing of the pivotal areas can be suspected but no microscopic evidence was found on the valve structure.
There are many reports in the literature about structural failures of mechanical heart valves affecting both mitral and aortic prostheses. The best known is the Björk–Shiley convexo–concave valve2 (Shiley, Inc, Irvine, Calif). Leaflet fracture with leaflet escape was reported for different bileaflet valves of more recent design and has led to market withdrawals. According to the frequency and the mode of the reported failure, a systematic design- or fabrication-related error is presumed.3
By contrast, sporadic reports of failing valves pertaining to widely accepted valves with numerous implants worldwide have to be considered.4
Different factors were identified contributing to the risk of leaflet damage, including cavitation, asymmetric leaflet closure, and surgical mishandling of the prosthesis.5
The mode of failure of the explanted valve remains unclear. No intermittent regurgitation was observed before the onset of continuous insufficiency; hence a single random incident is concluded. However, no data exist regarding the time of onset and development of occasional single-beat regurgitation and no information is available about any explanted specimen with this disorder. The differing severity of intermittent regurgitation in different patients is unexplained. Therefore, intermittent regurgitation may be regarded as a process, with asymmetric closure of the leaflets and leaflet overlap causing leaflet stress and thereby structural dysfunction. Unexpected in vivo performance of a mechanical heart valve should be elucidated thoroughly and careful follow-up of affected patients is warranted.
References
This article has been cited by other articles:
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  W. B. Eichinger, I. Hettich, S. Bleiziffer, R. Gunzinger, A. Hutter, R. Bauernschmitt, and R. Lange Intermittent regurgitation caused by incomplete leaflet closure of the Medtronic ADVANTAGE bileaflet heart valve: Analysis of the underlying mechanism J. Thorac. Cardiovasc. Surg., September 1, 2010; 140(3): 611 - 616. [Abstract] [Full Text] [PDF]
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