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Reduced access to TAVR to treat aortic stenosis in Canada compared to the US may affect mortality risk, potentially threatening lives

Philadelphia | April 25, 2023

A new study in the Canadian Journal of Cardiology comparing outcomes and access to transcatheter aortic valve replacement (TAVR) between Ontario and New York State found that patients in Ontario are more likely to die within a month of the procedure, possibly due to inadequate availability and long wait times.

A new study has found substantial regional differences in access to transcatheter aortic valve replacement (TAVR) and patient outcomes between Ontario and New York State. New York residents had improved access to TAVR and improved outcomes compared to Ontario. Statistical modelling also indicated that the same New York residents would have had worse outcomes had they been treated in Ontario. Resultsopens in new tab/window are published in the Canadian Journal of Cardiologyopens in new tab/window.

TAVR has revolutionized options for treating patients with symptomatic severe aortic stenosis, one of the most common and serious types of heart valve disease and has become the standard of care for a wide spectrum of patients over the last two decades. Current clinical practice guidelines recommend TAVR as the treatment of choice for patients deemed at prohibitive or high risk for surgical aortic valve replacement (SAVR) and a reasonable alternative for patients at intermediate or low risk. However, there are wide regional variations in access to TAVR.

In many jurisdictions, the demand for TAVR has exceeded capacity, resulting in poor access, with potentially a higher threshold for offering therapy or longer wait times and substantial wait-time morbidity and mortality.

“These potential patient harms must be weighed against the possible benefits of centralizing TAVR procedures to fewer specialized centers with potentially higher procedural volumes,” explained lead investigator Harindra Wijeysundera, MD, PhD, FRCPC, Schulich Heart Program, Sunnybrook Health Sciences Centre, University of Toronto, Canada. “In jurisdictions such as New York, there has been rapid dissemination of new TAVR centers, providing additional capacity, but with relatively low volumes at some institutions. Given the relationship between low operator-hospital volume and poorer outcomes seen in TAVR, this raised concerns of potentially poorer postprocedural outcomes being a possible clinical consequence if the availability of TAVR was more widespread.”

Because little is known about how these two opposing scenarios compare (potentially sicker patients preprocedurally, but with potentially improved postprocedural outcomes given the higher operator-hospital experience, versus less-sick patients with shorter wait times, but potentially poorer postprocedural outcomes because of lower operator-volume experience) investigators developed a study to address this gap in knowledge.

Investigators compared outcomes between Ontario, Canada, and New York State, USA, as a natural experiment comparing two healthcare systems with substantially different capacities to perform TAVR. Their objective was to determine whether differences in healthcare delivery in jurisdictions with high versus low access of care to TAVR translate to differences in postprocedural mortality and readmissions. In this observational, retrospective cohort study, investigators identified all Ontario and New York State residents over 18 years of age who received TAVR from January 1, 2012, to December 31, 2018. The primary outcomes were post-TAVR 30-day in-hospital mortality and all-cause readmissions.

The investigators found substantial differences in access between the two jurisdictions. In Ontario, with a population of 14.8 million and a surface area of 1,076,395 square kilometers, there were 5,007 TAVR procedures performed at 11 hospitals, with access rates increasing from 18 in 2012 to 87 TAVR per million in 2018. In New York State, with a population of 19 million and a surface area of 141,300 square kilometers, there were 16,814 TAVR procedures performed at 36 hospitals, with access rates increasing from 32 in 2012 to 220 TAVR per million in 2018. There was no difference in the rate of readmission at 30 days (14.6% in Ontario and 14.1% in New York State), but 30-day in-hospital death was higher in Ontario (3.1%) than in New York State (2.5%). Investigators calculated the observed versus expected outcomes for New York patients had they been treated in Ontario.

Observed versus expected (O/E) outcomes for New York State residents had they been treated in Ontario. The O/E ratio for mortality within 30 days after the procedure was 0.70 (confidence interval 95%), showing that patients in New York State had better outcomes compared with Ontario. The O/E ratio for readmission within 30 days after discharge was 0.95 (confidence interval 0.85-1.07) (Credit: Canadian Journal of Cardiology).

“It appears that having greater access to TAVR is associated with improved outcomes, potentially because of intervention earlier in the trajectory of the disease,” commented Dr. Wijeysundera. “This calls for further research to understand the optimal balance between overall TAVR capacity, as well as individual operator and institution volume.”

In an accompanying editorial, Stéphane Noble, MD, Structural Heart Unit, University Hospital of Geneva, Geneva, Switzerland, and colleagues noted that as a direct consequence of the increasing demand for TAVR, procedures are not being matched by the growth in capacity, waiting lists are progressively growing, and this is associated with a risk of death and hospitalization for heart failure while waiting for the procedure. High-volume centers report better results than low-volume centers, and this is mainly because of their organization and protocols. In addition, low-volume operators perform better at high-volume centers than at low-volume centers. “Indeed, access to timely treatment is as important as having access to high-volume centers with experienced operators who can perform complex procedures,” commented Dr. Noble.

“TAVR remains underperformed in Ontario compared with New York State (three-fold greater access in New York) and western European countries mainly because of funding difficulties and lack of capacities to cover a large territory. Access to timely treatment earlier in the disease process of aortic stenosis could actually be more cost effective and associated with a better quality of life,” concluded Dr. Noble.


Notes for editors

The article is “Regional Differences in Outcomes for Patients Undergoing Transcatheter Aortic Valve Replacement in New York State and Ontario,” by Harindra C. Wijeysundera, MD, PhD, Mario Gaudino, MD, Feng Qiu, MSc, Molly A. Olson, MS, Jialin Mao, MD, MS, Ragavie Manoragavan, BSc, Lisa Rong, MD, Derrick Y. Tam, MD, Peter C. Austin, PhD, Stephen E. Fremes, MD, and Art Sedrakyan, MD, PhD ( in new tab/window).

This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health (MOH) and the Ministry of Long-Term Care (MLTC). This study is also partially supported by the Office of the Assistant Secretary for Planning and Evaluation Patient-Centered Outcomes Research Trust Fund under Interagency Agreement (#750119PE060048), through the U.S. Food and Drug Administration (FDA) (Grant number U01FD006936).

The editorial is “Geographic Determinants of Outcomes After TAVR: Should We Favour Timely Access to TAVR Rather Than High Volume Per Centre?” by Stéphane Noble, MD, Sarah Mauler-Wittwer, MD, and Nana K. Poku, MD ( in new tab/window).

Both articles appear online ahead of the Canadian Journal of Cardiology, volume 39, issue 5 (May 2023) published by Elsevier.

Full text of the articles is available to credentialed journalists upon request. Contact Eileen Leahy at +1 732 238 3628or [email protected]opens in new tab/window to obtain copies. Journalists wishing to speak to the study’s authors should contact Katherine Nazimek at [email protected]opens in new tab/window. To reach the editorial’s authors for comment, contact Stéphane Noble, MD, at [email protected]opens in new tab/window.

About the Canadian Journal of Cardiology

The Canadian Journal of Cardiologyopens in new tab/window is the official journal of the Canadian Cardiovascular Societyopens in new tab/window. It is a vehicle for the international dissemination of new knowledge in cardiology and cardiovascular science, particularly serving as a major venue for the results of Canadian cardiovascular research and Society guidelines. The journal publishes original reports of clinical and basic research relevant to cardiovascular medicine as well as editorials, review articles, case reports, and papers on health outcomes, policy research, ethics, medical history, and political issues affecting practice. www.onlinecjc.caopens in new tab/window

About the Editor-in-Chief

Editor-in-Chief Stanley Nattel, MD, is Paul-David Chair in Cardiovascular Electrophysiology and Professor of Medicine at the University of Montreal and Director of the Electrophysiology Research Program at the Montreal Heart Institute Research Center.

About the Canadian Cardiovascular Society (CCS)

The CCSopens in new tab/window is the national voice for cardiovascular clinicians and scientists, representing more than 2,300 cardiologists, cardiac surgeons and other heart health specialists across Canada. We advance heart health for all by setting standards for excellence in heart health and care, building the knowledge and expertise of the heart team, and influencing policy and advocating for the heart health of all Canadians. For further information on the CCS visit in new tab/window.

About Elsevier

As a global leader in scientific information and analytics, Elsevier helps researchers and healthcare professionals advance science and improve health outcomes for the benefit of society. We do this by facilitating insights and critical decision-making with innovative solutions based on trusted, evidence-based content and advanced AI-enabled digital technologies.

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Together with the Elsevier Foundationopens in new tab/window, we work in partnership with the communities we serve to advance inclusion and diversity in science, research and healthcare in developing countries and around the world.

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Eileen Leahy


+1 732 406 1313

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