A new study from Barcelona has shown that in a subgroup of patients, direct transfer and triage in the angiosuite seems feasible, safe, and achieves significant reduction in hospital workflow times.
Marc Ribo (The Stroke Unit, Department of Neurology, Vall d’Hebron University Hospital, Vall d’Hebron Research Institute, Barcelona, Spain) and colleagues investigated the safety and feasibility of a new direct transfer to angiosuite protocol that they believe will dramatically reduce in-hospital workflow times.
In a number of acute ischaemic stroke studies conducted in recent years it has been shown that time from symptom onset to reperfusion is the most powerful predictor of outcome. In the first six to eight hours after symptom onset the chances of functional recovery without disability decrease 10–15% for each 30 minute delay to reperfusion.
Ribo et al studied in-hospital workflow metrics of all admitted patients with acute stroke at their comprehensive stroke centre who had undergone endovascular treatment between December 2015 and November 2016. They explain that in previous years, all patients with suspected acute stroke admitted to their institution followed one of two different admission protocols: (1) direct transfer to the emergency room (DTER) for initial clinical evaluation before a CT scan; or (2) direct transfer to the CT room (DTCT) for simultaneous clinical evaluation/CT scan. The second option was favoured but depended on preadmission notification by the emergency medical systems (Rapid arterial occlusion evaluation (RACE) score >47) and stroke team/CT scan immediate availability.
Starting June 2016, a third option was implemented: (3) direct transfer to the angiosuite (DTAS). This option was considered and favoured upon preadmission notification by the emergency medical systems (RACE score >4) and depending on stroke team/angiosuite immediate availability.
For the DTAS workflow protocol, patients underwent a quick neurological assessment performed by the stroke neurologist in charge before entering the angiosuite in order to confirm an NIHSS score >10, as a predictor of large vessel occlusion (LVO), and time from symptom onset <4.5 hours. If the NIHSS score was <10 or time from onset >4.5 hours the patient was excluded from the DTAS option and followed the DTER or DTCT admission protocol.
DTER and DTCT patients were selected for endovascular treatment according to a standard CT protocol (Alberta Stroke Program Early CT Score (ASPECTS) ≥6) and confirmation of LVO on CT angiography. DTAS patients underwent cone-beam CT (Xpert-CT, high dose/ fast acquisition, Allura Clarity FD 20/20 Philips 2015) in the angiosuite immediately before femoral artery puncture. Absence of intracranial haemorrhage and absence of large infarct signs were used as selection criteria for endovascular treatment. Confirmation of LVO could not be performed in the DTAS group.
All patients received IV t-PA, when indicated, after either conventional CT scan or Xpert-CT. Independently of the admission protocol, endovascular procedures were performed by experienced interventionalists using commercially available stent retrievers and aspiration catheters. At the end of the procedure recanalisation was assessed; complete recanalisation was considered if the thrombolysis in cerebral infarction (TICI) score was 2b or 3.
Between December 2015 and November 2016 (12 months) 201 patients were included: 87 DTER (43.3%), 74 DTCT (36.8%), 40 DTAS (19.9%).
“From the 40 patients in the DTAS group, 31 (77.5%) were transferred from another hospital where they had undergone a previous CT scan and 9 (22.5%) were primary admissions to our centre. Ten (25%) of the DTAS patients finally did not receive endovascular treatment: three patients (7.5%) showed an intracranial haemorrhage on Xpert-CT and seven (17.5%) did not show a treatable occlusion on the initial angiogram. The number of patients who did not receive endovascular treatment owing to the absence of a treatable occlusion on the initial angiogram, despite confirmation by previous CT angiography, was 1 (1.1%) in the DTER group and 4 (5.4%) in the DTCT group. The mean door-to-puncture time was significantly shorter in the DTAS group (17±8 min) than in the DTCT group (60±29 min; p<0.01). The door-to-puncture time was longer in the DTER group (90±53 min,) than in both other groups (p<0.01),” Ribo and colleagues write in the Journal of NeuroInterventional Surgery.
For analysis of the clinical outcome, only DTAS patients with confirmed LVO on the initial angiogram were included and compared with DTER and DTCT patients with confirmed LVO on the initial angiogram: DTAS: 30 patients, DTER: 86 patients, DTCT: 70 patients.
Ribo et al report that there were no significant differences in baseline characteristics between groups, including mean time from symptom onset to hospital admission (DTAS: 179 ±14 min, DTER: 199±20 min, DTCT 167±18 min, p=0.21) or the mean time from femoral puncture to recanalisation/end of procedure (DTAS: 61±6 min, DTER: 59±3 min, DTCT 57 ±3 min, p=0.88). However, the mean times from symptom onset to groin puncture (DTAS: 197±72 min, DTER: 279±156 min, DTCT 224±142 min, p=0.01) and symptom onset to recanalisation (DTAS: 257±74 min, DTER: 355±158 min, DTCT 279±146 min, p<0.01) were longer in the DTER group. The rate of complete recanalisation was similar between the three groups: DTAS: 83.3%, DTER: 82.6%, and DTCT: 72.5% (p=0.27).
Finally, safety was similar among the groups and there were no differences in the rate of symptomatic intracranial haemorrhage at 24 hours (DTAS: 5%, DTER: 6.9%, DTCT: 9.6%; p=0.66).
In terms of the median NIHSS score at 24 hours there were no differences: DTAS: 8 (5–15), DTER: 7 (2–18), DTCT: 8 (3–18) (p=0.81).
“However, the rate of dramatic improvement was significantly higher in the DTAS group, DTAS 48.6%, DTER 24.1%, DTCT 27.54% (p=0.01). We studied possible reasons for the association between DTAS and dramatic improvement. An adjusted model for admission NIHSS score, age, and recanalisation, showed that shorter onset-to-puncture time was an independent predictor of dramatic clinical improvement (OR=1.23, 95% CI 1.13 to 1.33; p<0.01). Patients who experienced a dramatic clinical improvement showed shorter times from onset to femoral puncture (182±70 vs. 215±90; p=0.03), and a receiver operating characteristic curve showed that >90% of such patients had a time from onset to femoral puncture of <298 min. The likelihood of achieving an onset-to-femoral puncture time <298 min was higher when the DTAS protocol was followed than with the other two protocols (OR=5.6; 95% CI 1.3 to 24.8; p=0.02),” the authors explain.
In conclusion, Ribo et al’s pilot study confirms that in patients with suspected acute stroke in the early time window, a direct transfer protocol to the angiosuite is feasible, safe, and helps to achieve a significant reduction in workflow times. Moreover, the authors maintain that this time saving might be associated with improved outcome in some cases.