The Surgical Management of Severe Aortic Stenosis In the Era of Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has emerged as a treatment option for severe and symptomatic aortic stenosis across the spectrum of surgical risk and has potentially transformed the surgical management of aortic stenosis. The objectives of this dissertation were: (1) To determine if the widespread introduction of TAVR had an impact on valve selection trends in those undergoing surgical aortic valve replacement (SAVR); (2) To compare valve-in-valve TAVR to redo surgery for a failed biological prosthesis; (3) To determine the safety and efficacy of adjunctive aortic root enlargement (ARE) to SAVR; (4) To determine the impact of various hypothetical scenarios of TAVR valve durability on the life expectancy of low-risk patients. Our piece-wise regression of 214,390 patients undergoing isolated primary mechanical or bio- logical SAVR from 2004-2016 in the United States estimated that the proportion of mechanical valves was decreasing more quickly during 2004-2009 (-2.81%/year, 95% confidence interval [95% CI], -3.03% to -2.60%), compared with 2010-2016. This suggest that the widespread introduction of TAVR did not, in of itself, accelerate the decline in mechanical valves. In a propensity-score matched analysis of 131 patient-pairs undergoing either valve-in-valve TAVR or redo surgery for a failed biological prosthesis, 30-day mortality (absolute risk difference: -7.5%; 95%CI: -12.6% to -2.3%), permanent pacemaker implantation, and blood transfusions were significantly lower with valve-in-valve. A multi-institutional propensity-score matched analysis showed that the addition of ARE to isolated SAVR was safe and did not confer additional early mortality or morbidity in 809 matched patient-pairs. Overall, these two analyses suggest ARE should be performed when necessary and may facilitate future valve-in-valve procedures, which may be the preferred approach for a failed biological prosthesis. Finally, in our discrete event simulation model, the durability of TAVR valves must be 70% shorter than that of surgical valves to result in reduced life expectancy in patients with similar demographics to those enrolled in the low-risk trials. However, in younger patients, the threshold for TAVR valve durability was substantially higher. These findings suggest that durability concerns should not influence the initial treatment decision regarding TAVR versus SAVR in older low-risk patients based on current evidence.

Department dc:contributor.department

Health Policy, Management and Evaluation

Year dc:date.issued

2020

Author dc:creator

• Tam, Derrick Y

Advisor dc:contributor.advisor

• Fremes, Stephen E.

• aortic stenosis
• aortic valve replacement
• decision analysis
• discrete event simulation
• health technology assessment
• transcatheter valves

Handle dc:identifier.uri

http://hdl.handle.net/1807/103298

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/103298