Post-TAVR strokes reported more frequently in comprehensive stroke centers
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In a cohort of patients who had transcatheter aortic valve replacement at 22 hospitals in Michigan, post-TAVR stroke was more common at institutions designated as comprehensive stroke centers, researchers reported.
Other outcomes did not vary by comprehensive stroke center status, indicating the difference might be due to better detection of stroke at comprehensive stroke centers, which suggests that raw stroke data as presently collected may not be the best way to determine the quality of an institution’s TAVR program, P. Michael Grossman, MD, interventional cardiologist at the University of Michigan Health Frankel Cardiovascular Center and professor of internal medicine and cardiovascular medicine at U-M Medical School, told Healio.
Data were derived from Grossman PM, et al. JACC Cardiovasc Interv. 2023;doi:10.1016/j.jcin.2022.10.020.
“Stroke is a publicly reported endpoint for TAVR centers,” Grossman said in an interview. “There may be a disincentive to report stroke, because centers that are theoretically doing a good job in reporting stroke might be put at a disadvantage in this public reporting model.”
Stroke after TAVR
Grossman and colleagues conducted an analysis of 6,231 patients (mean age, 79 years; 46% women) from 22 Michigan hospitals who underwent TAVR between January 2016 and June 2019 and were included in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry. Most patients were not treated with embolic protection devices.
The outcome of interest was in-hospital post-TAVR stroke, and the researchers compared data from patients who had procedures at Joint Commission-designated comprehensive stroke centers (CSC; 62.3%) vs. those who had procedures at non-CSC centers (37.7%).
“When we began looking at stroke, we saw that overall stroke rates were lower than had been reported in the pivotal trials” of TAVR systems, Grossman told Healio. “But we also saw significant variations in hospital stroke reporting, where some hospitals were essentially reporting no strokes, and others were reporting stroke rates of 2% to 3% annually. Looking at charts, the timing of the identification of stroke was very different across hospitals. And we knew there were different levels of stroke care among these hospitals, with some being Joint Commission-certified. We wondered if the level of stroke care might make a difference in what we have seen in reporting of stroke.”
CSC sites had higher rates of in-hospital post-TAVR stroke than non-CSC sites (2.65% vs. 1.15%; P < .001), Grossman and colleagues found. After adjustment, having the procedure at a CSC site was associated with elevated risk for in-hospital post-TAVR stroke (OR = 2.21; 95% credible interval, 1.03-4.62).
“Even after correcting for the variables that one would normally correct for in this kind of analysis, we found that hospitals that were certified stroke centers were more than twice as likely to identify patients with stroke as opposed to patients that were not,” Grossman told Healio. “That’s important because it might mean that we are underrecognizing strokes in some institutions. It was somewhat surprising to us that there was this big of a difference based on stroke center status.”
However, there was no difference between the groups in 30-day mortality (P = .428), acute kidney injury (P = .132), transfusion (P = .066) or 1-year survival with sustained quality of life (P = .855), according to the researchers.
Because there were no differences in these outcomes, differences in patient population are less likely to be the cause of the differences in stroke than the higher likelihood of a CSC to detect a stroke, Grossman told Healio.
“Patients treated at certified stroke centers numerically did just as well if not better” in the other outcomes, he said. “So we think there is something here about identification of stroke, and it may be, for lack of a better term, a more subjective outcome than the other objective endpoints that are used in these publicly reported quality metrics.”
Therefore, he told Healio, “agencies that are doing public reporting around these procedures should reconsider giving stroke the weight that it is given in their scoring systems.”
The way the data are currently collected does not allow major strokes to be separated from minor strokes in the reporting metrics, Grossman told Healio. “Ideally, we would get to a place where we could understand which patients are having major strokes that leave them debilitated vs. minor strokes,” he said. “However, there is a significant amount of data that suggests that even small strokes, or strokes identified only by differences on neuroimaging, have some long-term implications for patients. Neurocognitive function is worse in patients who have more embolic phenomena on these imaging studies. We want to do a better job at trying to prevent strokes during these procedures.”
‘Appropriate concern’
In a related editorial, Alexandra J. Lansky, MD, professor of medicine at Yale School of Medicine, cardiologist at Yale-New Haven Hospital and director of the Yale Heart and Vascular Clinical Research Program and the Yale Cardiovascular Research Center, and Yousif Ahmad, BMedSci, BMBS, MRCP, PhD, assistant professor of medicine and associate program director of the interventional cardiology fellowship at Yale School of Medicine, wrote that the differences in stroke rates could be due to ascertainment methods, but “could also be credibly explained by inherent differences in the treated patient populations. For example, alternative access TAVR is known to be associated with an increased risk of stroke and was more common in patients treated at CSC sites.
“A broader issue highlighted by this study is the prospect of stroke rates being used as a public reporting metric for TAVR centers,” they wrote. “The authors raise appropriate concern with this approach because sites treating higher-risk patients or with greater expertise in assessing and diagnosing stroke would be considered worse performers when the opposite may be true.”
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For more information:
P. Michael Grossman, MD, can be reached at pagross@med.mich.edu; Twitter: @grossman_md.
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