Direct to Angio‐Suite Large Vessel Occlusion Stroke Transfers Achieve Faster Arrival‐to‐Puncture Times and Improved Outcomes

Abstract

Background

For patients with large vessel occlusion (LVO) stroke, time to treatment with endovascular thrombectomy is crucial to prevent infarction and improve outcomes. We sought to evaluate the hub arrival‐to‐puncture times and outcomes for transferred patients accepted directly to the angio‐suite (LVO to operating room, LVO2OR) versus those accepted through the emergency department in a hub‐and‐spoke telestroke network.

Methods

Consecutive patients transferred for endovascular thrombectomy with spoke computed tomography angiography–confirmed LVO, spoke Alberta Stroke Program Early Computed Tomography score >6, and last known well–to–hub arrival <6 hours were identified. Our LVO2OR protocol began implementation in January 2017. The LVO2OR cohort includes patients who underwent endovascular thrombectomy from July 2017 to October 2020; the emergency department cohort includes those from January 2011 to December 2016. Hub arrival‐to‐puncture time and 90‐day modified Rankin scale score were prospectively recorded.

Results

The LVO2OR cohort was composed of 91 patients, and the emergency department cohort was composed of 90 patients. LVO2OR patients had more atrial fibrillation (51% versus 32%; P=0.02) and more M2 occlusions (27% versus 10%; P=0.01). LVO2OR patients had faster median hub arrival‐to‐puncture time (11 versus 92 minutes; P<0.001), faster median telestroke consult‐to‐puncture time (2.4 versus 3.6 hours; P<0.001), greater Thrombolysis in Cerebral Infarction score 2b to 3 reperfusion (92% versus 69%; P<0.001), and greater 90‐day modified Rankin scale score <2 (35% versus 21%; P=0.04). In a multivariable model, LVO2OR significantly increased the odds of 90‐day modified Rankin scale score <2 (adjusted odds ratio, 2.77 [95% CI, 1.07–7.20]; P=0.04) even when controlling for age, baseline modified Rankin scale score, atrial fibrillation, National Institutes of Health Stroke Scale score, M2 occlusion location, and Thrombolysis in Cerebral Infarction score 2b to 3.

Conclusions

In a hub‐and‐spoke telestroke network, accepting transferred patients directly to the angio‐suite was associated with dramatically reduced hub arrival‐to‐puncture time and may lead to improved 90‐day outcomes. Direct–to–angio‐suite protocols should continue to be evaluated in other geographic regions and telestroke network models.

Introduction

For patients with large vessel occlusion (LVO) stroke, time to treatment with endovascular thrombectomy (EVT) is crucial. ¹ , ² The optimal triage of patients with LVO first presenting to non–EVT‐capable hospitals in a telestroke network is unknown. Our hub‐and‐spoke system of care ³ involves rapid triage and transfer of eligible patients with LVO stroke from non–EVT‐capable to EVT‐capable hospitals via a direct–to–angio‐suite (LVO to operating room, LVO2OR) pathway. This pathway was implemented to reduce hub arrival‐to‐puncture times and improve patient outcomes by bypassing involvement of the hub emergency department (ED) and repeat imaging. Herein, we evaluate the impact of LVO2OR implementation for transferred patients on hub arrival‐to‐puncture time, telestroke consult‐to‐puncture time, EVT procedural results, and long‐term functional outcomes.

Methods

Included patients received initial assessment and treatment via our hub‐and‐spoke telestroke network, consisting of 24 spokes across 4 states. ⁴ A map of this network has been previously published. ³ Consecutive patients with anterior LVO stroke who presented to spoke hospitals and were transferred to the hub for EVT were identified from a prospectively maintained database, which includes demographics, medical history, presentations, treatments, and functional outcomes. ⁵

The LVO2OR protocol for transferred patients was implemented in January 2017. To be eligible for EVT through this protocol, patients were required to have spoke computed tomography (CT) angiography–confirmed LVO, Alberta Stroke Program Early CT score >6, and anticipated last known well–to–hub arrival <6 hours. All patients were directly transported from the hub helicopter landing pad or ambulance bay to the angio‐suite. Most patients do not experience significant changes in stroke severity during transfer, ⁶ but the National Institutes of Health Stroke Scale (NIHSS) was rapidly assessed en route to or in the angio‐suite before EVT. A decision was made about the need for intubation before EVT on angio‐suite arrival; conscious sedation was generally preferred. Flat‐panel CT was not routinely performed but was available at the discretion of the treating neurointerventionalist. For nearly all patients, EVT was pursued on the basis of prior spoke hospital imaging.

For the purposes of this study, the LVO2OR cohort includes patients who underwent EVT from July 2017 to October 2020. For the ED cohort, similar inclusion criteria were applied to identify transferred patients who underwent EVT within last known well <6 hours from January 2011 to December 2016 before LVO2OR implementation. During this period, our protocol was to obtain imaging on hub arrival, and 78% underwent hub magnetic resonance imaging before EVT. ⁷ Patients with posterior circulation LVO, those transferred with the intent of monitoring for decline instead of immediate EVT, and those with unavailable hub arrival time and/or arterial puncture time (3 patients) were excluded (Figure 1).

Figure 1.

Flow diagram of cohort inclusion and exclusion criteria.

ED indicates emergency department; LKW, last known well; and LVO2OR, direct‐to‐angio‐suite large vessel occlusion to operating room protocol.

Presenting NIHSS score and intravenous alteplase treatment candidacy at the spoke hospitals were determined by a hub neurologist via videoconference examination. ⁴ All patients underwent CT and CT angiography at the spoke hospital before transfer. ⁸ Alberta Stroke Program Early CT score and presence of LVO on CT angiography were determined by a vascular neurologist and confirmed by a neuroradiologist. ⁴ EVT treatment decisions at the hub were at the discretion of a vascular neurologist and neurointerventionalist. ⁹

Hub arrival‐to‐puncture time was obtained from the medical record and prospectively recorded. ¹⁰ Thrombolysis in Cerebral Infarction (TICI) scores were determined by a neurointerventionalist using the modified scale: 2a, partial filling <50%; 2b, partial filling ≥50%; and 3, complete perfusion. ¹¹ , ¹² Adequate reperfusion was considered TICI 2b to 3. ¹³ Symptomatic intracerebral hemorrhage was defined as intraparenchymal, intraventricular, or subarachnoid hemorrhage associated with symptoms during hospitalization. ¹⁴ The 90‐day modified Rankin scale (mRS) score was obtained by clinic evaluation or telephone call. ¹⁵

Median values with interquartile range were reported for continuous variables. Percentage and count were reported for categorical variables. Groups were compared using nonparametric Wilcoxon rank‐sum and Fisher exact tests, as indicated. Multivariable logistic regression analyses were performed to assess associations with outcomes. The primary outcomes were hub arrival‐to‐puncture time and 90‐day mRS score <2. Secondary outcomes were telestroke consult‐to‐puncture time and TICI 2b to 3 reperfusion. Patients with baseline disability were included in the primary analyses, but this variable was controlled for when analyzing 90‐day outcomes using a multivariable model. Furthermore, a sensitivity analysis was performed, excluding patients with baseline mRS score >1 as another means of controlling for this variable. It was determined a priori that covariates would include age, baseline mRS score, NIHSS score, TICI 2b to 3 status, and any other variables that were significantly different between groups. Two‐tailed P<0.05 was interpreted as statistically significant. Analyses were performed with SPSS version 23.0 (IBM Corp).

Results

A total of 181 transferred patients meeting inclusion criteria were identified. The mean age was 67±15 years, median NIHSS score was 18 (interquartile range, 13–21), and 48% were women. The LVO2OR cohort was composed of 91 patients, and the ED cohort was composed of 90 patients (Table). Rates of atrial fibrillation (51% versus 32%; P=0.02) and M2 occlusion location (27% versus 10%; P=0.01) were higher in the LVO2OR group. Otherwise, there were no significant differences in history or presentation, including NIHSS score and last known well–to–hub arrival time. 

Table  .

Comparisons in Transferred Patient Characteristics and Outcomes Between Those Accepted Through the ED and Those Accepted Directly to the Angio‐Suite (LVO2OR)

Characteristic	P value	ED cohort (N=90)		LVO2OR cohort (N=91)
		Average/count	Spread/%	Average/count	Spread/%
Age, mean, y	0.14	65	±15	69	±15
Female sex	0.88	44	49%	43	48%
Baseline mRS score >1	0.03	3	3%	12	13%
Baseline mRS score >2	0.70	3	3%	4	6%
Atrial fibrillation	0.02	29	32%	46	51%
Diabetes	0.59	17	19%	21	23%
Hypertension	0.12	64	71%	54	59%
Coronary disease	1.00	14	16%	14	15%
Stroke/TIA	0.20	9	10%	16	18%
Spoke alteplase	0.33	67	74%	60	67%
NIHSS score, median	0.86	17	14–20	18	12–22
LKW‐to‐arrival time, median, h	0.96	3.8	3.3–4.3	3.9	2.9–4.6
Hub arrival‐to‐puncture time, median, min	<0.001	92	61–118	11	9–16
Telestroke‐to‐puncture time, median, h	<0.001	3.6	3.1–4.2	2.4	2.0–2.8
ICA terminus occlusion	0.12	16	18%	8	9%
M1 occlusion	0.34	65	72%	58	64%
M2 occlusion	0.01	9	10%	24	27%
TICI 2b–3	<0.001	62	69%	80	92%
Stentriever used	0.23	44	49%	36	40%
Symptomatic ICH	0.19	10	11%	5	6%
90‐d mRS score <3	0.26	35	42%	37	48%
90‐d mRS score <2	0.04	18	21%	27	35%

Spread is SD or interquartile range, where appropriate. ED indicates emergency department; ICA, internal carotid artery; ICH, intracerebral hemorrhage; LKW, last known well; LVO2OR, direct‐to‐angio‐suite large vessel occlusion to operating room protocol; M1, first middle cerebral artery segment; M2, second middle cerebral artery segment; mRS, modified Rankin scale; NIHSS, National Institutes of Health Stroke Scale; TIA, transient ischemic attack; and TICI, Thrombolysis in Cerebral Infarction.

The LVO2OR cohort had a faster median hub arrival‐to‐puncture time (11 versus 92 minutes; P<0.001; Figure 2) and median telestroke consult‐to‐puncture time (2.4 versus 3.6 hours; P<0.001). Although there was more TICI 2b to 3 reperfusion in the LVO2OR cohort (92% versus 69%; P<0.001), there was no significant difference comparing the procedural approach, with a similar proportion of cases using a stentriever in both groups. There was also a similar proportion of symptomatic intracerebral hemorrhage in both groups.

Figure 2.

Effect of the direct–to–angio‐suite large vessel occlusion to operating room (LVO2OR) protocol on hub arrival‐to‐puncture times at the hub hospital.

The proportion of patients achieving 90‐day mRS score <2 was significantly higher in the LVO2OR cohort (35% versus 21%; P=0.04). In a multivariable model to control for confounding factors, LVO2OR significantly increased the odds of 90‐day mRS score <2 (adjusted odds ratio [OR], 2.77 [95% CI, 1.07–7.20]; P=0.04) even when controlling for age, baseline mRS score, atrial fibrillation, NIHSS score, M2 occlusion location, and TICI 2b to 3 status. In a sensitivity analysis excluding patients with baseline mRS score >1, the proportion of patients achieving 90‐day mRS score <2 was significantly higher in the LVO2OR cohort (41% versus 22%; P=0.01), and LVO2OR significantly increased the odds of 90‐day mRS score <2 (adjusted OR, 3.13 [95% CI, 1.37–7.15; P=0.01) even when controlling for age, atrial fibrillation, NIHSS score, M2 occlusion location, and TICI 2b to 3 status.

Discussion

In a hub‐and‐spoke telestroke network, a direct–to–angio‐suite transfer protocol (LVO2OR) for EVT‐eligible patients with LVO stroke reduced hub arrival‐to‐puncture times. LVO2OR patients also had improvement in EVT procedural efficacy as well as improved functional outcomes.

The LVO2OR transfer protocol decreased hub arrival‐to‐puncture time by over an hour, demonstrating the effectiveness of such a pathway in expediting acute care for patients with LVO stroke in telestroke networks. Although previously studied telestroke metrics focus on the timeliness of tPA (tissue‐type plasminogen activator) “drip‐and‐ship” administration or other elements of transport infrastructure, ³ this study demonstrates a singular intervention for dramatic reduction in diagnosis‐to‐intervention time. ¹⁶ Moreover, this reduction in time may have contributed to the measured improved functional outcomes. ¹⁷ Furthermore, there are likely additional, unmeasured benefits to the approach, including hub ED resource use optimization.

Other studies of direct–to–angio‐suite protocols, although not using organized telestroke networks like ours, have shown mixed results. Two corroborate our findings of significant time savings, ¹⁸ , ¹⁹ whereas another showed that overall arrival‐to‐procedure end time was similar. ²⁰ Indeed, the 2 with significant time savings reported improved 90‐day outcomes, as well. ¹⁸ , ¹⁹ These mixed data support the need for further studies within different geographies using different emergency medical services and hospital transfer approaches.

The ED cohort before implementation of our LVO2OR protocol did experience longer than expected hub arrival‐to‐puncture times, with a median of 92 minutes. There are several factors that may relate to delay to treatment. Perhaps the most significant is that our protocol was to obtain imaging upon hub arrival during this period, and 78% underwent hub magnetic resonance imaging before EVT. ²¹ There was also significant time spent for the evaluation of patients by ED providers; our current LVO2OR protocol bypasses repeated imaging and the ED entirely. Although telestroke was used during both cohorts, our advanced notification system was less protocolized during the ED cohort period. An optimized telestroke system is an essential part of the successful implementation of our direct–to–angio‐suite protocol (Figure 3). Critical components for the success of this network and expedited medical decision making include the following: an integrated multidisciplinary team of emergency clinicians, neurologists, and neurointerventionalists, videoconference capabilities, real‐time review of diagnostic data, and early activation of technicians, nurses, and anesthesia staff. ²² The early evaluation and identification of patients with LVO stroke at spoke hospitals likely enables efficient EVT preparation while patients are in transit, thereby reducing time to treatment and functionally expanding eligibility. ²³ , ²⁴

Figure 3.

Multidisciplinary process map for a direct–to–angio‐suite large vessel occlusion to operating room (LVO2OR) protocol.

ASPECTS indicates Alberta Stroke Program Early Computed Tomography score; CTA, compute tomography angiography; ED, emergency department; EMS, emergency medical services; ICU, intensive care unit; ID, identification; ETA, estimated time of arrival; LKW, last known well; LVO, large vessel occlusion; MRN, medical record number; OR, operating room; and RN, registered nurse.

This study has several limitations. Although our telestroke network represents a geographically large region, other networks have unique geographic and system considerations that may limit generalizability. Additional studies within other networks are warranted. Furthermore, a larger sample size may have allowed the detection of differences in outcomes using other mRS thresholds. Although procedural approaches to both groups were generally standardized (with equivalent stentriever use rates), advances in catheters and devices represent a possible confounder given the necessarily time‐staggered nature of the 2 groups. Still, we controlled for successful reperfusion in our outcomes analysis, and this consideration is unlikely to affect hub arrival‐to‐puncture times.

Our real‐world study demonstrates that in a large hub‐and‐spoke network, a direct–to–angio‐suite protocol for patients transferred with LVO stroke is associated with decreased hub arrival‐to‐puncture times and may lead to improved 90‐day outcomes. Direct–to–angio‐suite protocols should continue to be evaluated in other geographic regions and telestroke network models.

Sources of Funding

The National Institutes of Health, National Institute of Neurological Disorders and Stroke, supported this work (R25 NS065743).

Disclosures

None relevant.