Letter by Seners and Baron Regarding Article, "Effect of Interhospital Transfer on Endovascular Treatment for Acute Ischemic Stroke".

Abstract

HomeStrokeVol. 50, No. 9Letter by Seners and Baron Regarding Article, “Effect of Interhospital Transfer on Endovascular Treatment for Acute Ischemic Stroke” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter by Seners and Baron Regarding Article, “Effect of Interhospital Transfer on Endovascular Treatment for Acute Ischemic Stroke” Pierre Seners, MD, PhD and Jean-Claude Baron, MD, ScD Pierre SenersPierre Seners Neurology Department, Sainte-Anne Hospital, INSERM U1266, Université de Paris, France Search for more papers by this author and Jean-Claude BaronJean-Claude Baron Neurology Department, Sainte-Anne Hospital, INSERM U1266, Université de Paris, France Search for more papers by this author Originally published5 Jul 2019https://doi.org/10.1161/STROKEAHA.119.026088Stroke. 2019;50:e259Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: July 5, 2019: Ahead of Print To the Editor:In their article, Venema et al1 assessed the effects of inter-hospital transfer on (1) time to treatment and (2) functional outcome, in acute stroke patients with large vessel occlusion (LVO) undergoing endovascular treatment (EVT). They compared these 2 outcomes between patients directly admitted to an EVT-capable center (mothership) and those transferred to such center from a non-EVT-capable center (drip-and-ship), using the MR-CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry, a nationwide prospective observational study of all patients treated with EVT across the Netherlands since EVT became standard-of-care. This registry includes all patients who receive groin puncture, regardless of whether the procedure was pursued or stopped at this stage.They found that (1) time from arrival at the first hospital to groin puncture was significantly longer in the drip-and-ship patients and (2) drip-and-ship patients less often achieved functional independence (modified Rankin Scale score 0–2, 34% versus 42%, respectively; adjusted odds ratio: 0.69 [95% CI, 0.54–0.89]). They conclude “Direct transportation of patients potentially eligible for EVT to an intervention center may improve functional outcome.”1An important feature of Venema et al’s1 study—intrinsic to the MR-CLEAN registry—is that only LVO patients who received groin puncture were considered, that is, the fraction of drip-and-ship patients transferred for potential EVT but who did not undergo groin puncture were excluded a priori. Indeed, as the authors indicate, patients who deteriorated or substantially improved during transfer underwent repeat computed tomography/computed tomography angiography on arrival at the EVT center,1 and those with early recanalization did not proceed to groin puncture and were, therefore, excluded. Given that 77% of their cohort received intravenous thrombolysis (IVT), this design likely impacted their results because post-IVT recanalization within 3hours of IVT start occurs in ≈20% of drip-and-ship patients,2,3 and early post-IVT recanalizers have lower baseline National Institutes of Health Stroke Scale, shorter thrombus and more distal occlusions,2,4 implying better functional outcomes. Consequently, excluding from the MR-CLEAN registry those drip-and-ship patients who have recanalized on repeat pre-EVT imaging inevitably leads to underestimating the functional outcome of real-life drip-and-ship patients. In their discussion, Venema et al1 briefly mention this limitation but do not discuss its potential impact, and go on to generalize their conclusion to the overall LVO stroke care pathway, whereas their findings apply only to those LVO patients who effectively undergo groin puncture.A similar design was also used in another study5 based on the STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) Registry of EVT-treated patients, which excludes all early recanalizers even if they underwent groin puncture. Unsurprisingly, it also found better 3-month functional outcome in the mothership subgroup.5 In contrary, another study on IVT-treated patients referred for EVT—including those who eventually did not receive EVT—, reported similar 3-month functional outcome in mothership and drip-and-ship patients.3Considering the time-dependence of the functional benefit from EVT and the longer treatment delays inherent to the drip-and-ship paradigm,1,3,5 better functional outcome may indeed exist in patients treated according to the mothership, as compared with the drip-and-ship, paradigm. However, Venema et al’s1 study only concerned the subset of LVO stroke population eligible for EVT who received groin puncture, and for the reasons explained above likely overestimated this difference. Ongoing trials are expected to provide the real effect of paradigm on functional outcome.Pierre Seners, MD, PhDJean-Claude Baron, MD, ScDNeurology DepartmentSainte-Anne HospitalINSERM U1266, Université de ParisFranceDisclosuresNone.FootnotesStroke welcomes Letters to the Editor and will publish them, if suitable, as space permits. Letters must reference a Stroke published-ahead-of-print article or an article printed within the past 4 weeks. The maximum length is 750 words including no more than 5 references and 3 authors. Please submit letters typed double-spaced. Letters may be shortened or edited.