Pivoting system fracture in a bileaflet mechanical valve: A case report

Abstract

A leaflet escape occurred in a low profile bileaflet mechanical prosthesis manufactured by TRI-Technologies that had been implanted for 3 years in the mitral position of a 32 year old patient. The escaped leaflet had embolized and was subsequently located by an abdominal computerized axial tomography scan and ultrasound in the terminal portion of the aortic bifurcation. The embolized leaflet was removed 3 months after valve replacement surgery. In an attempt to determine the cause of the escape the retrieved embolized leaflet was investigated. Techniques employed included visual examination aided by stereo-microscopy, x-ray imaging and scanning electron microscopy. One of the ears had fractured and was missing from the leaflet. Chipping was observed at the leaflet ear position on both the inflow and outflow surfaces. Visual and SEM observations found fractographic river-lines that indicated an apparent origin at the inflow surface of the ear nearest to the straight 'B-datum' line or coaptation edge. The origin seemed to be in the radius between the leaflet ear and the leaflet body. SEM observation of the remaining intact ear showed wear marks on both the inflow and outflow sides of the leaflet ear that corresponded to the suspected origin of fracture. It is believed that the use of boron alloyed pyrolytic carbon material and the leaflet's homogeneous monolithic structural design were factors that contributed to this adverse event.

A review of the bio-tribology of medical devices

“…Excessive wear may cause the leaflet to escape or strut fracture, and finally result in the failure of mechanical heart valves. A tribology-related leaflet escape was reported by Zhang et al [120] in a low profile bileaflet mechanical prosthesis, where excessive wear of the leaflet outflow edge was identified.…”

Spontaneous leaflet fracture resulting in embolization from mechanical valve prostheses

“…Following its introduction in 1979, by 2003 >600 cases were known to have valve fractures, often leading to sudden cardiac deaths . In addition to the BSCC valve, there are other valves that carry a higher risk for leaflet fracture and subsequent leaflet escape, of which the most prominent is the ED prosthesis (as illustrated by our case), followed by the TRI Technologies (TRI Technologies Prosthetic Heart Valve, Ltda, Belo Horizonte, Brazil) mechanical valve …”

“…1 In addition to the BSCC valve, there are other valves that carry a higher risk for leaflet fracture and subsequent leaflet escape, of which the most prominent is the ED prosthesis (as illustrated by our case), followed by the TRI Technologies (TRI Technologies Prosthetic Heart Valve, Ltda, Belo Horizonte, Brazil) mechanical valve. [2][3][4][5][6][7][8] The ED prosthesis (Baxter Healthcare Corp., Edwards Division) is a bileaflet mechanical heart valve first introduced and implanted in 1982. After approximately 20,000 valve prostheses were implanted the valve was withdrawn from the market in 1988 after at least 46 cases of leaflet escape were registered by the manufacturer.…”

Unravelling Surface Modification Strategies for Preventing Medical Device‐Induced Thrombosis

“…[116] On the other hand, due to scratches at the valve hinge location, PyC components continue to malfunction and discharge carbon particles into the blood, potentially contaminating it. [117] Diamond-Like Carbon Coatings: Tetrahedral carbon (TaC) and diamond-like carbon (DLC) films made of amorphous carbon have strong wear resistance, low friction coefficients, and chemical inertness, all of which contribute to good corrosion resistance. [118,119] As containing significant amounts of sp 3 hybridized carbon atoms, DLC possesses typical properties of diamond, meanwhile TaC is regarded as the purer type of DLC with trace of sp 2 hybridized bonded carbon.…”