Study highlights disparity in TAVI outcomes based on availability

Harindra C Wijeysundera

Research has highlighted significant regional variations in the availability of transcatheter aortic valve implantation (TAVI) and patient outcomes between Ontario, Canada and New York State, USA.

Patients in New York enjoyed better TAVI 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 published in the Canadian Journal of Cardiology.

According to current clinical guidelines, TAVI 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 TAVI varies significantly across regions.

Lead investigator Harindra Wijeysundera (University of Toronto, Toronto, Canada), stated that the potential benefits of centralising TAVI procedures to a fewer number of specialised 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 TAVI centres, which has increased the capacity but resulted in relatively low volumes at some facilities. Because low operator-hospital volume is linked to poorer TAVI outcomes, this raises concerns about the potential for poorer post-procedural outcomes as a possible clinical consequence if TAVI 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 the two regions as a natural experiment. They aimed to examine whether differences in healthcare delivery in regions with high versus low access to TAVI translated to differences in post-procedural mortality and readmissions. All Ontario and New York State residents aged 18 years or older who underwent TAVI between 1 January 2012, and 31 December  2018 were identified by the investigators. The primary outcomes of the study were post-TAVI 30-day in-hospital mortality and all-cause readmissions.

The study found significant differences in TAVI 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 TAVI procedures were performed at 11 hospitals, with access rates increasing from 18 in 2012 to 87 TAVI 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 TAVI 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.

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

In an editorial that accompanied the study, Stéphane Noble and colleagues from the University Hospital of Geneva (Geneva, Switzerland) highlighted that the increasing demand for TAVI is outpacing the growth in capacity, leading to longer waiting lists and an increased risk of death or hospitalisation for heart failure while patients wait for the procedure.

The authors also noted that high-volume centres tend to report better outcomes due to their organisation and protocols, and that low-volume operators perform better at high-volume centres compared to low-volume centres. The editorial concludes by emphasising that access to timely treatment is crucial, and that access to both high-volume centres with experienced operators and timely treatment is vital for optimal patient outcomes.


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