A comparative study of mechanical and homograft prostheses in the pulmonary position

Homografts (HGs) are considered the gold standard for pulmonary valve replacement. However, to avoid further operations, the use of mechanical valves (MVs) might be considered, especially in patients who had had multiple prior operations or require an additional MV in another position.

Data of 19 patients with MVs were compared with 19 patients with HGs, matched for age, sex, and follow-up time. Development of gradient and regurgitation were analyzed using hierarchical multilevel modeling. Mean follow-up time was 5.8 +/- 2.6 years.

The initial pressure gradient was significantly lower in HGs compared with MVs (11.7 mm Hg vs 19.2 mm Hg, p = 0.006), but the annual increase was significantly higher in HGs compared with MVs (4.0 mm Hg/year vs 1.1 mm Hg/year, p = 0.008). The initial regurgitation grade was significantly higher in HGs compared with MVs (0.81 vs 0.37, p < 0.001), and the annual increase was also significantly higher in HGs compared with MVs (0.09 grade/year vs -0.01 grade/year, p < 0.001). Reintervention was required in 3 HGs (stenosis), and in 2 MVs (thrombosis after irregular anticoagulation, dysfunction due to ingrowth of tissue). Freedom from reintervention was not significantly different between both groups (p = 0.32).

The hemodynamic performances of MVs are superior to HGs because gradient and regurgitation develop significantly slower. However, this does not lead to lower reintervention rates. Because reoperations of MVs can be prevented by appropriate surgical technique and strict anticoagulation, MVs should be considered for the pulmonary position, especially in patients who require anticoagulation treatment for additional MVs or rhythm disturbances.