Evolving stroke treatment guidelines may put added pressure on transfer systems.
Nearly half of transfers of patients from a primary to a comprehensive stroke center for endovascular therapy are futile in the semirural setting, according to research from France. The findings were published online October 16, 2018, ahead of print in the Journal of NeuroInterventional Surgery.
“Most of the studies about endovascular treatment are from comprehensive stroke centers with neuroradiology services onsite,” lead author Denis Sablot, MD (Centre Hospitalier de Perpignan, France), told Neurovascular Exchange in an email. “Thus, little is known about patients with acute ischemic stroke and large vessel occlusion who are admitted far away from these services.”
Sablot and colleagues conducted a retrospective analysis of data collected in a 6-year prospective registry of patients admitted to their primary stroke center within 4.5 hours of acute ischemic stroke symptom onset. All patients included in the study received an MR angiography indicating the presence of large vessel occlusion (LVO) without large cerebral infarction (DWI-ASPECTS ≥ 5).
Transfers Futile in 45% of Patients
Among the 529 patients screened for mechanical thrombectomy, 278 (52.6%) were transferred to a comprehensive stroke center. Transfer was found to be futile in 125 of these patients (45%). The three main reasons for futile transfer were: clinical improvement and reperfusion on MRI on arrival at the comprehensive stroke center (58.4%), clinical worsening and/or infarct growth (16.8%), and longer than expected inter-hospital transfer time (11.2%).
According to Sablot, there are several potential explanations for the high rate of futile transfer. These include the fact that his hospital is located at quite a distance from a comprehensive stroke center. During the long transfer time, he said, nearly 30% of the patients experienced recanalization with the use of recombinant intravenous tPA. Another potential risk is that patients will deteriorate during the transfer, which also occurred. “It is estimated that 1 to 2.5% of endovascular treatments will be not performed for each minute lost,” he reported.
Finally, “some of the patients were also transferred for prevention of an expected deterioration that did not occur,” Sablot noted.
Futile transfer can perhaps be minimized, he said, as new information on the predictive value of collateral status is gathered and utilized for clinical decision-making. Efforts also have been focused on shortening transfer times, but this is limited by the physical distance between primary and comprehensive stroke centers.
The investigators were unable to uncover any factors that predicted futile transfer due to clinical improvement/reperfusion on MRI. However, baseline higher NIHSS (21 vs 17; P = 0.01) and lower DWI-ASPECTS score (5 vs 7; P = 0.001) were associated with futile transfer due to clinical worsening/infarct growth on MRI.
Sablot emphasized that these findings are relevant only to semirural settings with stroke networks similar to his. He pointed out, however, that such settings are common in many regions around the world.
“The findings of this study would not apply to the majority of the US urban stroke systems of care,” said Maxim Mokin, MD, PhD (University of South Florida, Tampa), who commented on the study for NVX. “However, in more rural regions in the US, similar long distances between tPA only and endovascular-equipped stroke centers are not uncommon.” The authors described the distance of 156 km (97 miles) between the primary and comprehensive stroke center where the treatment was performed.
Transfer to Distant Sites Takes Too Long
“Transfers do take a long time,” noted Mokin. The process includes 87-94 minutes for door-in to door-out at primary stroke centers (PSC) plus 86-95 minutes to comprehensive stroke center (CSC) door-in. This averages close to 3 hours of transfer time for a distance of 97 miles, he noted.
“Our strategy [of] transferring patients to a distant comprehensive stroke center does not [allow for] adequate access to care for the population,” concluded Sablot. “The optimal distribution of interventional neuroradiology services should take into account transport times and effectiveness of endovascular therapy after transfer.”
Sablot wondered whether it is a good strategy “to transfer patients or [should we] convert some [remote] and high-volume primary stroke centers with a large population catchment area and with long transfer delays to comprehensive stroke centers?” If stroke networks centralize endovascular acute ischemic stroke therapy in larger comprehensive stroke centers, he added, “the benefits of such centralized care must be weighed against the risks related to longer transport times. Decisions on the optimal distribution of interventional neuroradiology services should take into account both transport times and the need to maintain adequate care access.”
As guidelines for stroke management change with emerging data, transfer systems will need to evolve to meet increasing demand, noted Mokin.
“There is emerging evidence that [endovascular therapy] may be of value in patients with mild (NIHSS < 6) stroke symptoms, and a randomized trial studying [it] in this population of patients is underway,” he said. “If thrombectomy proves of clinical value in such patients, even more patients with LVO will require transfers to CSCs. This will likely put a major strain on the systems that are involved in patient transfer. . . . Such geographically remote areas are likely the best target for ambulances capable of administering IV tPA.”
Source:
Sablot D, Dumitrana A, Leibinger F, et al. Futile inter-hospital transfer for mechanical thrombectomy in a semirural context: analysis of a 6-year prospective registry. J NeuroIntervent Surg. 2018;Epub ahead of print.
Disclosures:
Sablot and Mokin report no relevant conflicts of interest.
