Original article
Adult cardiac
Pathologic Evaluation of 28 Mitroflow Pericardial Valves: A 12-Year Experience

https://doi.org/10.1016/j.athoracsur.2014.07.031Get rights and content

Background

Mitroflow pericardial valves (model A12) are used for aortic valve replacement with favorable hemodynamic results, and are ideal for patients with a small aortic annulus as the pericardium is mounted outside the stent frame. We report the morphologic findings in explanted Mitroflow valves from our institution and demonstrate pathologic changes leading to explantation.

Methods

From 2001 to 2013, 28 Mitroflow valves were analyzed at our institution. Demographic data was recorded. The excised valves were analyzed by gross and microscopic examination. After pathologic examination, mode of failure was determined.

Results

During the 12-year period, 28 valves were explanted. The 28 patients, with a mean age at implant of 72.2 ± 5.7 years (range, 60 to 81 years), included 16 males (57%). The mean interval between index surgery and explantation was 4.5 ± 3.4 years (range, 3 months to 11 years). Structural valve deterioration was seen in 18 (64%) patients; mean age at implantation was 72.1 ± 5.69 years with an implant duration of 6.25 ± 2.6 years. Findings in patients with structural valve deterioration included cusp thickening (n = 18), tears (n = 17), pannus deposition (n = 17), and calcification (n = 14). Nonstructural valve deterioration and endocarditis was seen in 1 (4%) and 7 patients (25%), respectively. One valve explanted at post mortem did not contribute to the patient’s death.

Conclusions

Structural valve deterioration was seen in 18 of 19 explanted valves with implant durations of at least 30 months, and is related to valve design. It appears that clinicians should carefully consider Mitroflow valve implantation in all patients, even in patients older than 65 years old, given the early presence of structural valve deterioration.

Section snippets

Material and Methods

After obtaining research ethics board approval, a review of pathology records was undertaken (January 2001 through July 2013). Demographic data (age at implant, sex, indication for implant and explant, implant duration, and blood and tissue cultures) were recorded. All specimens were fixed in 10% buffered formalin, photographed, and examined. All valves were examined for cusp tears (types I through IV), thickening, calcification (grades 0 through 4), pannus (grades 0 through 4), and thrombus 7,

Patient Demographics

Twenty-eight valves were available (Table 1), including those obtained from 2 patients explanted at post mortem and 1 patient explanted perioperatively because of paravalvular leak. Excluding the perioperative explant, and among the remaining 27 patients, with a mean age at implant of 72.2 ± 5.67 years (range, 60 to 81 years), there were 15 male patients (56%). The interval between index surgery and explantation was 4.5 ± 3.4 years (range, 3 months to 11 years). When we excluded those with IE,

Comment

Early models of the Mitroflow pericardial valve (model A11) were prone to failure in the aortic position in patients older than 70 years of age, with freedom from valve-related reoperation and SVD being 48% ± 5% and 39.2% ± 9.8% at 10 years, respectively 9, 10. In one study, 78% of patients were explanted because of SVD [3]. Early prosthesis failure was also reported in the mitral position, with re-replacement occurring at 55 months as a result of cusp tears and calcification [11]. The valve

References (31)

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