Objectives: During the last years, age recommendations for the use of biological prostheses rather than mechanical prostheses for surgical aortic valve replacement (sAVR) have been lowered considerably. We evaluated survival rates, major adverse cardiac events (MACEs), and reoperation risks after surgical (sM-AVR) and biological (sB-AVR) AVR, to provide data for the optimal prosthesis choice for middle aged patients between 50 and 65 years. Methods: We performed a population-based cohort study using Austrian Health System data from 2010-2020. Patients undergoing isolated sAVR (n=3761) were categorized into sM-AVR (n=1018) and sB-AVR (n=2743) groups. Propensity score matching (PSM) was applied to balance covariates. The primary endpoint was all-cause mortality. Secondary endpoints included MACEs, reoperation, stroke, bleeding, and survival post-reoperation. Outcomes were assessed using Cox regression and Kaplan-Meier analyses. Results: Patients undergoing sM-AVR had significantly lower all-cause mortality compared to sB-AVR (HR=1.352, p=0.003). sB-AVR was associated with higher risks of MACEs (HR=1.182, p=0.03) and reoperation (HR=2.338, p=0.002). Stroke and bleeding rates were comparable. All results were sustained after PSM. Conclusion: The findings highlight increased mortality, MACEs and reoperation risks associated with sB-AVR compared to sM-AVR. We observed superior long-term outcomes after sM-AVR, suggesting the need to reevaluate the expanding use of sB-AVR in younger patients.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics committee/IRB of lower Austria (GS1-EK-4/722-2021) gave ethical approval for this work

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors