Tissue vs. Mechanical Aortic Valve Replacement in Medicare Beneficiaries

S. Wolfe¹, L. Wei², A. Hayanga¹, D. Chauhan³, C. Mascio³, J. Rankin⁴, V. Badhwar¹, J. Mehaffey^1
1West Virginia University, Morgantown, West Virginia ²WVU Heart and Vascular Institute, Morgantown, West Virginia ³WVU Medicine Children's Hospital, Morgantown, West Virginia ⁴WVU, Morgantown, West Virginia

Purpose: Prosthesis selection for aortic valve replacement (AVR) must balance valve durability with need for oral anticoagulation (OAC) as part of shared decision-making. Given evolving strategies of lifetime patient management, we evaluated longitudinal outcomes of patients aged 65 years or greater undergoing tissue vs mechanical AVR in the modern era.

Methods: Using the United States Centers for Medicare and Medicaid Services claims database, we evaluated all beneficiaries undergoing isolated surgical AVR with tissue or mechanical valves between January 2018 and December 2022. Procedures were identified using diagnosis-related group and International Classification of Diseases 10th revision codes. The primary outcomes were 5-year survival, readmission for stroke, bleeding complications, or valve reintervention. Doubly robust risk-adjustment was performed using inverse probability weighting (IPW) propensity scores as well as multilevel regression and Cox Proportional Hazards time to event analysis. Separate subgroup analyses evaluated patients aged 65-70, as well as those with preoperative end stage renal disease on dialysis.

Results: A total of 81,741 beneficiaries were identified as undergoing tissue (n=73,751) or mechanical (n=7,990) AVR. Over the 5-year study period, prior to risk adjustment, valve reintervention was very low in both groups (0.8% vs 0.7%, p=0.121) with higher rates of readmission for bleeding in the mechanical group (3.6% vs 1.2%, p< 0.0001). After robust risk adjustment, compared to a mechanical AVR, tissue AVR was associated with superior longitudinal survival (HR 0.68, p< 0.0001) and lower all cause readmission (HR 0.83, p< 0.0001), stroke (HR 0.84, p=0.008), bleeding (HR 0.40, p< 0.0001) and composite stroke, bleeding, valve reintervention or death (HR 0.77, p< 0.0001, Figure) with no difference in valve reintervention (p=0.437). Similar findings were observed in the youngest subgroup, age 65-70 years (mechanical= 1,852 vs tissue= 17,698), with tissue valves being associated with superior survival (HR 0.63, p< 0.0001), lower all cause readmission (HR 0.91, p< 0.0001) and bleeding (HR 0.36, p< 0.0001) but no difference in valve reintervention (HR 0.90, p=0.313). In risk-adjusted patients with renal failure on dialysis (688 mechanical vs 1926 tissue), tissue AVR was associated with significantly lower readmission for bleeding (HR 0.27, p< 0.0001) but significantly higher valve reintervention (HR 1.93, p=0.002) with no difference in 5-year survival (HR 1.01, p=0.926).

Conclusion: In Medicare beneficiaries, tissue AVR was associated with improved survival and freedom from bleeding complications with similar reintervention rates compared to mechanical valves in all subgroups except those with end-stage renal disease. These data support the use of tissue valves in patients aged 65 and older without renal failure.

Identify the source of the funding for this research project: NIH NHLBI # 2UM1 HL088925 12