Why are post-TAVR stroke rates higher at comprehensive stroke centers?
Comprehensive stroke centers (CSCs) are associated with higher in-hospital stroke rates after transcatheter aortic valve replacement (TAVR), according to a new analysis published in JACC: Cardiovascular Interventions.[1] Does this mean these centers are providing below-average care? Or is there something more behind these findings?
Strokes remain one of the most significant complications seen in TAVR patients. Hospitals participating in clinical trials have long been linked to higher stroke rates than are typically seen in day-to-day practice—but what about CSCs? The study’s authors explored this issue at length.
“A CSC designation identifies the most comprehensive center with the highest level of resources and capabilities for recognition, management, and clinical care for acute stroke patients,” wrote first author Paul Michael Grossman, MD, an interventional cardiologist with the Frankel Cardiovascular Center at the University of Michigan, and colleagues. “Staff in CSCs are specifically trained in the recognition of signs and symptoms of stroke and to rapidly activate systems of care designed to diagnose and treat these patients. Whether CSC status is associated with post-TAVR stroke rates is unknown.”
Grossman et al. examined data from more than 6,000 patients who underwent TAVR from January 2016 to June 2019. All patients were treated at one of 22 facilities participating in the Michigan TAVR Collaborative, a partnership between the Blue Cross Blue Shield Michigan Medicine Collaborative and the Michigan State Thoracic and Cardiovascular Surgery Quality Collaborative. Those facilities were separated into two groups—centers that have received a CSC designation from the Joint Commission and centers that have not.
The group found that 62.3% of patients were treated at one of nine CSC sites included in the study. The remaining 37.7% of patients were treated at one of 12 non-CSC sites. There were slightly more men in both groups and the mean age was approximately 79 years old for both groups.
Overall, the mean stroke rate was significantly higher among patients in the CSC group (2.65%) than patients in the non-CSC group (1.15%). This may seem counterintuitive at first—since patients treated at CSCs were thought to face a lower stroke risk—but the study’s authors emphasized that it is likely because the CSCs are simply better at identifying the signs of stroke.
One finding that supports this possibility is that there was “no significant difference between CSC and non-CSC sites across other important post-TAVR clinical outcomes. The rates of in-hospital acute kidney injury, 30-day mortality and one-year survival, for instance, were all similar between the two groups.
Also, sites earn the CSC designation by putting the best possible systems in place to identify and treat stroke patients. So patients treated at these sites may be more likely to have their symptoms correctly identified.
In addition, CSC sites may have been more likely to experience in pivotal TAVR research in the procedure’s earlier days.
“CSC hospitals were more likely to have participated in the seminal TAVR randomized controlled trials and may be more likely to identify post-TAVR neurologic deficits because of their participation … in these clinical trials,” the authors wrote. “Moreover, it is possible that the rigorous protocols used to assess neurologic outcomes in these trials are likely to be incorporated into their clinical practice.”
The authors also noted that CSC hospitals may be more likely to care for complex patients—but further research is needed to explore that possibility.
Considering these different factors, Grossman et al. concluded that 30-day stroke rates may not an effective quality metric for evaluating patient care. More research is needed to learn more about this relationship between CSCs and post-TAVR stroke outcomes.
Read the full study here.
Additional insights on TAVR stroke rates
In a separate editorial, Alexandra Lansky, MD, a cardiologist with the Yale School of Medicine and Yale-New Haven Hospital, and co-author Yousif Ahmad, BMedSci, BMBS, MRCP, PhD, examined the implications of these findings.
In their evaluation, published in full in JACC: Cardiovascular Interventions, Lansky and Ahmad wrote that there are potential issues with publicly reporting post-TAVR stroke rates.[2] Sites could under-report strokes, for instance, or try to avoid treating certain high-risk patients.
“The current study speaks to some of the challenges of using post-procedural stroke as a basis for ranking or comparing TAVR programs,” the two co-authors wrote. “With the expansion of TAVR in the United States and moves to increase public reporting of TAVR outcome data, it is necessary to thoughtfully select metrics that will lead to the intended improvements in quality and patient outcomes rather than metrics that may affect physician or institutional behavior to the detriment of best practices and patient care. In this case, centers reporting higher stroke rates after TAVR, because they may be caring for higher-risk patients or have more integrated neurologic assessment and treatment approaches, should not be incentivized to lower their standards.”
Read more here.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.