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

Newswise —

A recent research discovered significant regional variations in the availability of transcatheter aortic valve replacement (TAVR) and patient results between Ontario and New York State. Patients in New York enjoyed better TAVR accessibility and outcomes compared to those in Ontario. Furthermore, statistical analysis suggested that if the same New York residents were treated in Ontario, they would have experienced poorer outcomes. The findings are featured in the Canadian Journal of Cardiology.

The treatment of patients with symptomatic severe aortic stenosis, one of the most severe and common types of heart valve disease, has been transformed by TAVR, which has become the standard of care for a diverse range of patients in the last 20 years. According to current clinical guidelines, TAVR is the preferred treatment for patients who are considered high-risk or ineligible for surgical aortic valve replacement (SAVR) and a viable option for those at intermediate or low risk. Despite this, access to TAVR varies significantly across regions.

In numerous jurisdictions, the demand for TAVR has surpassed the available capacity, leading to limited access, which can result in a higher threshold for treatment or longer wait times, leading to significant wait-time morbidity and mortality.

Lead investigator Harindra Wijeysundera, MD, PhD, FRCPC, Schulich Heart Program, Sunnybrook Health Sciences Centre, University of Toronto, Canada, stated that the potential benefits of centralizing TAVR procedures to a fewer number of specialized centers with potentially higher procedural volumes must be weighed against the possible patient harms. "In areas such as New York, there has been a rapid expansion of new TAVR centers, which has increased the capacity but resulted in relatively low volumes at some facilities. Because low operator-hospital volume is linked to poorer TAVR outcomes, this raises concerns about the potential for poorer post-procedural outcomes as a possible clinical consequence if TAVR availability becomes more widespread," he said.

As there is limited knowledge on how these two contrasting scenarios compare (potentially sicker patients before the procedure, but with potentially better post-procedural outcomes due to higher operator-hospital experience, versus less sick patients with shorter wait times, but potentially poorer post-procedural outcomes due to lower operator-volume experience), researchers conducted a study to bridge this knowledge gap.

To address this issue, the researchers conducted an observational, retrospective cohort study that compared outcomes between Ontario, Canada, and New York State, USA, as a natural experiment. They aimed to examine whether differences in healthcare delivery in regions with high versus low access to TAVR translated to differences in postprocedural mortality and readmissions. All Ontario and New York State residents aged 18 years or older who underwent TAVR between January 1, 2012, and December 31, 2018, were identified by the investigators. The primary outcomes of the study were post-TAVR 30-day in-hospital mortality and all-cause readmissions.

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

Dr. Wijeysundera noted that the study results suggest that greater access to TAVR is linked with better outcomes, possibly due to early intervention in the disease trajectory. He emphasized the need for additional research to determine the ideal balance between overall TAVR capacity and individual operator and institution volume.

In an editorial that accompanied the study, Dr. Stéphane Noble and colleagues from the University Hospital of Geneva in Switzerland highlighted that the increasing demand for TAVR is outpacing the growth in capacity, leading to longer waiting lists and an increased risk of death or hospitalization for heart failure while patients wait for the procedure. The authors also noted that high-volume centers tend to report better outcomes due to their organization and protocols, and that low-volume operators perform better at high-volume centers compared to low-volume centers. The editorial concludes by emphasizing that access to timely treatment is crucial, and that access to both high-volume centers with experienced operators and timely treatment is vital for optimal patient outcomes.

The editorial highlights the funding and capacity issues faced by Ontario in providing TAVR services, resulting in lower access compared to New York State and some western European countries. The editorial also emphasizes the importance of timely treatment in the disease process of aortic stenosis, which can be cost-effective and lead to a better quality of life for patients. Overall, the study and the accompanying editorial shed light on the need for further research to understand the optimal balance between TAVR capacity and individual operator and institution volume, as well as the importance of timely access to treatment for patients with aortic stenosis.