The ARREST trial involved 616 London Ambulance Service clinicians, 860 of our patients and 35 hospitals across London. It took 10 years from inception to completion and was made possible thanks to a generous research grant from the British Heart Foundation. The project was coordinated by the Clinical Audit & Research Unit at LAS with support from the London School of Hygiene and Tropical Medicine and Kings College London.
What was ARREST?
ARREST was a randomised controlled trial which compared direct conveyance to a Cardiac Arrest Centre (one of the 7 Heart Attack Centres, HACs, in London) with the current standard of care (conveyance to the geographically closest Emergency Department, ED). Patients were included if they were successfully resuscitated following an out of hospital cardiac arrest with a presumed cardiac cause, and did not meet the current criteria for HAC conveyance (ST elevation on their ECG).
Why was ARREST needed?
We know that certain groups of patients benefit from being taken by our clinicians directly to specialist hospitals, even if that means driving past the closest Emergency Department. We already have pathways for this in London for patients with STEMI (heart attack), Stroke and Major Trauma.
It would seem sensible to also convey patients following a cardiac arrest directly to a hospital which has 24/7 access to specialist cardiac and intensive care facilities so that they have immediate access to specialist treatment. But the existing evidence didn’t tell us for sure if this was beneficial or not. The International Liaison Committee on Resuscitation (ILCOR) said that a clinical trial was needed so that we could know for sure what the best thing to do for this group of patients was.
ARREST was the first and only randomised trial in the world to answer this specific question.
What did it show?
ARREST showed that survival amongst patients resuscitated following an Out of Hospital Cardiac Arrest, who do not have ST elevation on their ECG, was no different when they were taken to a specialist hospital compared with the local ED. These patients also had no difference in their neurological outcomes at hospital discharge or 3 months after their cardiac arrest. This is good news as it indicates that not all patients after cardiac arrest need really aggressive intervention, and what they actually need is a period of stabilisation and supportive treatment which can be delivered in any hospital in London.
What does it mean for LAS?
Conveyance pathways in LAS are determined based on all of the available evidence and in partnership with the wider healthcare system. There is currently no specific pathway for resuscitated patients without ST elevation on their ECG and LAS clinicians should continue to follow JRCALC+ guidelines and refer to the admission criteria for specialist centres outlined in the Patient Care Handbook.
For most patients without ST elevation on their 12-lead ECG following cardiac arrest, the current guidelines recommend conveyance to the nearest Emergency Department, and ARREST shows that this is safe and appropriate.
Additionally, it means our current pathway of conveying most patients quickly to the nearest ED, and reserving the specialist centres for those with specific needs such as those having a STEMI cardiac arrest is probably the best course of action.
Results: The full results have been published in The Lancet, one of the world’s leading scientific journals.