Aortic Valve Prosthesis Choice in Dialysis Patients: A Review of Medicare Data

W. Lutfi¹, M. Grasty², N. J.. Goel¹, A. Iyengar³, S. Pan¹, M. Ibrahim⁴, K. M. Lawrence¹, W. Y. Szeto¹, N. D. Desai¹, C. Brown^1
1University of Pennsylvania, Philadelphia, Pennsylvania ²Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania ³University of Pennsylvania, Flushing, Michigan ⁴University of Pennsylvania, wyndmoor, Pennsylvania

Purpose: The optimal choice between bioprosthetic or mechanical surgical aortic valve replacement (SAVR) for dialysis patients is debated. The rapid adoption of transcatheter aortic valve replacement (TAVR) complicates decision-making further. This study compared outcomes between prosthesis choices for AVR using Medicare data.

Methods: Inpatient Medicare MedPAR files from 2009 to 2019 were queried for dialysis patients who underwent de novo bioprosthetic AVR (bAVR), mechanical AVR (mAVR), and TAVR. Patients who had concomitant mitral valve, tricuspid valve, aortic arch surgery, or infective endocarditis were excluded. ICD 9 and 10 procedure codes were used to identify bAVR, mAVR, and TAVR procedures. Two parallel but separate comparisons were made: bAVR versus mAVR and SAVR (bAVR + mAVR) versus TAVR. Propensity score matching (1:1) was used to match for age, sex, Elixhauser comorbidities, years on dialysis, and coronary revascularization either surgical or percutaneous. The primary outcome was overall survival analyzed using Kaplan-Meier methods and secondary outcomes were 3-year and 5-year rates of aortic valve reintervention, readmission for heart failure readmission for endocarditis, readmission for bleeding complications, ischemic stroke, and kidney transplant. Cumulative incidence functions with death as a competing risk were used to compare the secondary outcomes.

Results: 2,590 patients underwent mAVR, 4,752 bAVR, and 7,739 TAVR; respectively, the mean ages were 61.5, 66.6, and 73.2 years (P < 0.001) and mean Elixhauser scores were 9.2, 9.7, and 11.3 (P < 0.001). 1,080 (41.7%) mAVR patients had a concomitant coronary artery bypass graft compared to 2,264 (47.7%) bAVR, and rates of percutaneous coronary intervention within 3 months of AVR were 359 (13.9%), 684 (14.4%) and 1,788 (23.1%) for mAVR, bAVR, and TAVR respectfully. Unmatched Kaplan Meier analysis yielded median survivals of 2.3, 2.1, and 1.7 years for mAVR, bAVR, and TAVR respectively (P < 0.001).
Matching between mAVR and bAVR yielded 2,467 patients each. Overall survival was similar (Figure 1) with median survivals at 2.3 years for mAVR and 2.2 years for bAVR (P=0.252). Table 1 shows the cumulative incidence with death as a competing risk modelling for secondary outcomes. Rates of valve reintervention (lower for mAVR), GI bleeding, and bleeding readmissions (higher for mAVR) were significantly different between groups.
Matching between SAVR and TAVR yielded 3,206 patients each. Overall survival curves cross (Figure 1) with worse early survival for SAVR (P=0.650). Comparing secondary outcomes (Table 1) demonstrates lower CHF readmissions and higher endocarditis and kidney transplant rates for SAVR compared to TAVR.

Conclusion: Dialysis patients undergoing SAVR and TAVR have poor survival and high bleeding risk regardless of prosthesis choice. Bleeding complications were higher for mAVR compared to bAVR. While the incidence of valve re-intervention is significantly higher for bAVR versus mAVR the overall incidences of re-intervention were low.

Identify the source of the funding for this research project: This study was internally funded by the department of cardiothoracic surgery.