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The pathology of TRI-Tech valve leaflet escape.

BACKGROUND AND AIM OF THE STUDY
The study aim was to investigate leaflet escape in the TRI-Tech mechanical valve, as reported in three patients.


METHODS
Among the three patients, one patient with a mitral prosthesis from which leaflet escape occurred underwent a successful reoperation. However, two patients with an aortic prosthesis from which leaflet escape occurred died suddenly. In addition, 150 unimplanted TRI-Tech valve prostheses were evaluated.


RESULTS
Tab fracture was observed in all of the escaped leaflets, with a height asymmetry of 0.33 mm in the mitral valve, and 0.55 and 0.41 mm, respectively, in the two aortic valves. Height tab asymmetry was present in all unimplanted valves: this was <0.20 mm in 90% of valves, and >0.20 mm in 10% (in one valve the asymmetry was >0.35 mm). Height asymmetry was greatest in valves sized 21 to 25 mm. A review of data provided by the TRI-Tech quality control unit failed to demonstrate any reference to checking for tab symmetry.


CONCLUSION
Significant tab malalignment was observed in the TRI-Tech valves in which tab fracture and leaflet escape had occurred. Tab asymmetry was also present in all unimplanted valves; this was >0.20 mm in 10% of units, and in one case was as high as in valves that had undergone leaflet escape. As tolerance for tab asymmetry is unknown and the risk of rupture is unpredictable, an interruption of the implant program with prophylactic replacement of the implanted TRI-Tech valves must be considered judicious.