Radiation-associated bioprosthetic valve dysfunction: an initial case-control analysis

Radiation therapy (RT) for intrathoracic and breast malignancies has been associated with long-term valvular heart disease (VHD) in native valves. However, its impact on bioprosthetic heart valves remains unclear. We aimed to assess changes in transvalvular gradients following RT in patients with previously implanted bioprosthetic valves.

We identified 23 patients who underwent bioprosthetic valve implantation followed by chest RT and compared them with matched controls who did not receive RT. Serial echocardiographic gradients were analyzed post-implantation, pre-RT, and at two intervals post-RT (within 12 months and at 12-24 months). Univariable linear regression was used to evaluate associations between RT dose metrics, timing of RT, and changes in transvalvular gradients.

Transvalvular gradients remained stable in control patients but increased significantly over time in the RT group (Friedman's test P < 0.0001). Both total RT dose and mean heart RT dose significantly predicted increases in transvalvular gradients within 12 months (R² = 0.41, P = 0.001) and between 12 and 24 months (R² = 0.62, P < 0.0001) of RT completion. Shorter time between valve implantation and RT also predicted greater gradient increases. No patients required re-intervention during the follow-up period.

Chest RT is associated with early, dose-dependent elevations in transvalvular gradients among patients with bioprosthetic valves. Although the observed changes were modest and did not necessitate re-intervention, these findings highlight the need for long-term surveillance and further research to understand the durability of irradiated bioprosthetic valves.