A presentation at this year’s Society of Thoracic Surgeons (STS) conference suggests mechanical valves might lead to better survival compared to bioprosthetic valves in patients aged 60 or younger undergoing SAVR even though it seems like they’re going out of style.
- Mechanical SAVR valves have been around in one form or another since the 1960s, but have fallen out of favor in recent years.
- Previous analyses suggested mechanical valves have advantages over tissue valves in middle-aged patients, but lifelong anticoagulation requirements makes them a hard sell.
Researchers examined STS registry data on ~109k patients ages 40 to 75 years who received isolated bioprosthetic (94k) or mechanical (15k) AVR over 11 years and found that mechanical valve use decreased by about half (from 20% in 2008 to below 10% in 2019).
Despite the declining use of mechanical AVR, its benefits were clear over the study’s median 5.4 year follow-up, with patients aged 40-59 seeing the most significant mortality benefits.
- Patients aged 40-49 had a 31% lower all-cause mortality risk when receiving mechanical AVR compared to bioprosthetic.
- For patients aged 50-59, the benefit was less dramatic, but still significant coming in at a 13% lower all-cause mortality risk.
While these mortality risks might seem convincing, there are several caveats to keep in mind, including the significant differences in patient characteristics between mechanical and bioprosthetic recipients.
- Patients receiving bioprosthetic valves tended to be older (65.2 vs 55.7 years).
- They also often had lower BMI (31.0 vs 32.2 kg/m2).
- Bioprosthetic patients also had higher rates of hypertension (78.7% vs 71.8%) or prior PCI (6.7 vs 3.7%).
- However, bioprosthetic recipients had severe aortic insufficiency less often (15.3% vs 23.6%).
The study’s design also wasn’t powered to make any certain conclusions due to its reliance on registry data, meaning a randomized head-to-head trial would be needed to confirm these outcomes.
The Takeaway
When it comes to AVR, it’s pretty clear that it’s not a “one-valve fits all” type of situation, especially in the case of mechanical valves. While the data is still less-than-certain, this presentation suggests that there could be benefits to keeping mechanical AVR on the table, at least for healthier patients under 60.
