Determinants of Bioprosthetic Aortic Valve Degeneration

Abstract

Objectives: The aim of the present long-term study was to assess the incidence and mode of valve hemodynamic deterioration (VHD) of bioprosthetic aortic valves, as well as associated factors.

Background: Modern definitions of bioprosthetic valve deterioration recommend the use of echocardiography for the assessment of transprosthetic gradients and valvular regurgitation.

Methods: A total of 466 consecutive patients (mean age 73.5 ± 7.5 years, 56.0% women) underwent surgical bioprosthetic aortic valve replacement between 1994 and 2014. Clinical assessment, transthoracic echocardiography, and laboratory testing were performed at baseline and follow-up. VHD was defined as mean transprosthetic gradient ≥30 mm Hg and/or at least moderate valvular regurgitation on echocardiography. Patient-prosthesis mismatch was defined as an effective orifice area indexed to body surface area ≤0.8 cm²/m².

Results: Patients were followed for a median of 112.3 months (interquartile range: 57.7 to 147.7 months). Among patients with complete follow-up (n = 383), 70 subjects (18.3%; 4.8% per valve-year) developed VHD after a median of 32.4 months (interquartile range: 12.9 to 87.2 months; stenosis, n = 45; regurgitation, n = 16; both, n = 9). Factors associated with VHD by multivariate regression analysis were serum creatinine >2.1 mg/dl (hazard ratio [HR]: 4.143; 95% confidence interval [CI]: 1.740 to 9.866; p = 0.001), porcine tissue valves (HR: 2.241; 95% CI: 1.356 to 3.706; p = 0.002), arterial hypertension (HR: 3.022; 95% CI: 1.424 to 6.410; p = 0.004), and patient-prosthesis mismatch (HR: 1.931; 95% CI: 1.102 to 3.384; p = 0.022). By Kaplan-Meier analysis, elderly subjects showed faster development of VHD (age <70 years, 133.5 months [95% CI: 116.2 to 150.8 months]; 70 to 80 years, 129.1 months [95% CI: 112.4 to 145.7 months]; >80 years, 100.3 months [95% CI: 63.6 to 136.9 months]; p = 0.023). By multivariate Cox regression, age, diabetes, concomitant coronary artery bypass grafting, creatinine, and VHD (p < 0.05) were significantly associated with mortality.

Conclusions: On the basis of echocardiography, every fifth patient developed VHD after surgical bioprosthetic heart valve replacement. VHD was associated with renal impairment, the use of porcine tissue valves, arterial hypertension, and patient-prosthesis mismatch. Patients younger than 70 years were not affected by faster VHD.

Keywords: bioprosthetic aortic valves; echocardiography; risk factors; valve hemodynamic deterioration.