Large proportion of patients are found not to have LVO stroke after transfer has taken place, a retrospective study finds.
More than half of stroke patients with suspected large-vessel occlusion (LVO) who are transferred to an endovascular-capable center do not undergo thrombectomy, according to a retrospective, single-center study. Performing CT angiography (CTA) prior to transfer could provide a practical means of reducing the number of unnecessary transfers, the study authors argue.
“Over the last 2 years, our stroke team has noticed a large number of thrombectomy transfers who do not end up undergoing the procedure,” write Julia Yi, MD (University of Illinois, Chicago, IL) and colleagues. “To minimize time to recanalization, the decision to transfer a patient for thrombectomy is often based on the severity of the clinical exam rather than brain vascular imaging.” The most commonly used clinical score is the National Institutes of Health Stroke Scale (NIHSS).
To determine whether there might be a more effective way to identify those eligible for thrombectomy, Yi and colleagues retrospectively reviewed clinical and transfer data on 192 consecutive patients transferred to a single endovascular-capable center for possible thrombectomy via stroke code activation from 2015 through 2016.
The findings were published online March 30, 2017 ahead of print in the Journal of NeuroInterventional Surgery.
Overall, 105 transferred patients (54%) did not undergo thrombectomy. The most common reason was absence of LVO on CTA after transfer (68%). In addition, a NIHSS score < 10 was the strongest predictor of not undergoing thrombectomy, with 88% of such patients not having the procedure, while 52% of those with a NIHSS > 20 did undergo thrombectomy (P < 0.001).
Transfer via helicopter was associated with lower likelihood of having thrombectomy, while those who arrived within 5 hours of symptom onset were more likely to undergo the procedure.
According to the study authors, “primary stroke centers … have reason to develop the capability to rapidly acquire and interpret a CTA in patients with suspected LVO prior to transfer. Such efforts may reduce the costs associated with unnecessary thrombectomy transfers.”
‘Futile’ Transfers Likely to Continue
But in an email, Maxim Mokin, MD, PhD, (University of South Florida, Tampa, FL), who was not affiliated with the study, told Neurovascular Exchange that futile transfers are unlikely to ever be eliminated completely.
“This study confirms the previous published findings where approximately 30-60% of acute stroke transfers initially considered for thrombectomy end up ‘futile.’ Each of these publications is unique, representing experience from different types of hospital networks and geographic locations,” Mokin said. “It is unlikely that based on clinical severity evaluations alone we could reach 90-100% accuracy, thus the issue of ‘futile’ strokes is likely to persist.”
As to whether CTA prior to transfer is the best approach, however, Mokin said he remains uncertain. “While a vascular study at an outside hospital could more reliably confirm or rule out large-vessel occlusion, the question remains whether such an approach would adversely affect the outcomes by greatly increasing transfer time and thus delaying thrombectomy,” he added.
A recent study by Liang et al suggested that pre-transfer CTA does not delay transfer if it takes place rapidly, at the same time that arrangements for transfer are being made.
Mokin also identified another hole in currently available information. “We lack the data on how many patients who qualify for thrombectomy do not get transferred to endovascular-equipped hospitals,” he noted. “What happens to such patients? What are their clinical and imaging characteristics, and outcomes? Thus, the overall understanding of this issue remains incomplete.”
Mokin also observed that large multicenter trials and national registry trials are needed in order to develop “a deeper understanding and to design more effective ways to select and transfer patients with acute stroke.”
Source:
Yi J, Zielinski D, Ouyang B, et al. Predictors of false-positive stroke thrombectomy transfers. J NeuroInterv Surg. 2017;Epub ahead of print.
Disclosures:
Yi and Mokin report no relevant conflicts of interest.
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