Age-stratified outcomes of bioprosthetic and mechanical aortic valve replacements in an Australian cohort of 13 377 patients

OBJECTIVES: To quantify age-stratified outcomes of bioprosthetic valve (BV) and mechanical valve (MV) surgical aortic valve replacement (AVR) in Australian patients. DESIGN: Retrospective cohort study using population-based linked hospital morbidity and mortality data. SETTING: Public and private hospitals. PARTICIPANTS: Patients aged 18 years and over undergoing AVR from 2001 to 2013, stratified by age (18–64 years; 65+ years). MAIN OUTCOME MEASURES: Age-standardized index AVR rates; rates and multivariable-adjusted (age, sex, Charlson Comorbidity Index) incidence rate ratios (IRRs) for reoperation, incident cardiovascular events (hospitalization or death for acute myocardial infarction (AMI), stroke, major hemorrhage or thromboembolism) and mortality (cardiovascular and all-cause). RESULTS: Our cohort comprised 13 377 patients, of whom 3464 (26%) were aged 18–64 years. Annual age-standardized AVR rates increased by 2.7% with BV implants increasing in both age groups. After 5 years of follow-up, patients implanted with BV had lower rates of stroke (IRR: 0.40, 95% CI 0.27 to 0.60) and hemorrhage (IRR: 0.36, 95% CI 0.26 to 0.50). Among patients 65+ years, those implanted with BV had lower rates of AMI, hemorrhage, and cardiovascular and all-cause mortality than those implanted with MV (IRR: 0.71, 95% CI 0.53 to 0.96; IRR: 0.77, 95% CI 0.62 to 0.95; IRR: 0.80, 95% CI 0.69 to 0.92 and IRR: 0.85, 95% CI 0.74 to 0.97, respectively). After 6–10 years of follow-up, reoperation rates among patients 18–64 years were markedly higher in those implanted with BV compared with MV (IRR: 5.48, 95% CI 2.38 to 12.62) and rates of AMI were lower among patients implanted with BV compared with MV (IRR: 0.49, 95% CI 0.26 to 0.94). Among patients 65+ years rates of cardiovascular and all-cause mortality remained significantly lower for patients implanted with BV compared with MV. CONCLUSIONS: This study provides real-world evidence of AVR use and outcomes. Use of BV implants is increasing irrespective of age. Valve choice in younger patients requires thorough evaluation of patient factors influencing both short-term outcomes and longer-term risks of reoperation, stroke and hemorrhage.