The efficacy of intra-arterial therapy for the treatment of acute ischaemic stroke has now been established, but it has also been observed that the faster the brain is reperfused, the higher the chance of a good outcome. Therefore, says Tudor Jovin (University of Pittsburgh School of Medicine, Pittsburgh, USA), the efficiency and workflow of the entire team caring for the acute stroke patient must now gravitate around how the procedure can be made faster. He maintains that a time of 90 minutes to move the patient from door-to-groin puncture is still too long and the goal should be to reduce that time to 60 minutes or less.
Speaking at the Live Interventional Neuroradiology & Neurosurgery Course (LINNC; 22–24 June, Paris, France) Jovin said that it has been discovered that roughly every 30 minutes delay from symptoms onset to reperfusion translates to about 10% decrease in the likelihood of a good outcome. “It is clear that there is a very strong relationship between time of symptoms onset and reperfusion and we need to get these patients to the angiosuite to reperfuse as fast as possible,” he said.
Jovin explained that there are critical steps in the treatment process in which stroke teams have the opportunity to shorten these times, stemming from first medical contact at the hospital on arrival; emergency room arrival; first image; groin puncture; and finally, reperfusion.
“Around these critical steps we have to start to develop some metrics that we use to measure our efficiency. Very useful metrics are picture-to-puncture or picture-to-reperfusion. These are physiological metrics. They reflect the time that you spend from when you establish that the patient has a small infarct, that the patient has mismatch, that the patient has favourable physiology for treatment to when you reperfuse the brain. The other important metric is the metric that captures the efficiency of a system to move the patient through as fast as possible, which is door-to-groin. Both picture-to-puncture and door-to-groin have been shown to be strongly correlated with outcome,” Jovin said.
He presented the door-to-groin times that were recorded in the Merci Registry, which he believes is the most representative dataset that captures how efficient in terms of treatment US hospitals treating endovascular stroke were at the time IMS III was ongoing. The door-to-groin time in the Merci Registry was 2.7 hours median, which Jovin maintains is “very sobering” and largely explains why all the previous trials (IMS III, MR RESCUE) were negative. “Every 30 minutes lost represents a 10% chance of a good outcome, therefore, if we take three hours to move the patient from door-to-groin, then there is no surprise that these trials were negative,” Jovin said. He described those results as a wakeup call to stroke teams to get their act together.
On the pre-hospital side, the task now, he said, is to develop systems of care that will allow patients to be adequately identified in the field and send them to the appropriate hospital where they can be treated with endovascular therapy.
In this vein, Jovin pointed out that while the era of solid evidence of thrombectomy has been established in a number of trials, it should be noted that many of these trials used hand-picked centres from the standpoint of expertise in acute stroke interventions; therefore, these treatment times are not representative for every stroke centre, and an average stroke centre is likely to have worse times than what was reported in these trials.
For example, in ESCAPE (the most efficient trial) median door-to-groin time was 90 minutes, while in SWIFT PRIME it was 95 and in REVASCAT it was 109. Picture-to-puncture time was 50 minutes in ESCAPE, 63 minutes in SWIFT PRIME and 68 minutes in REVASCAT. Putting those figures into perspective, Jovin reported that in the treatment of myocardial infarction, the door-to-balloon time (equivalent to door-to-reperfusion) has to be 60 minutes, and if a certain proportion of patients do not fulfil this metric at a particular hospital Medicare may impose financial consequences. In comparison, neurointerventionalists are far behind.
“The recent trials took place in the best possible centres and they achieved times that cardiologists are just laughing about. How can we improve? Clearly 90 minutes from door to groin is still too long. We need to get to 60 minutes or to 30 minutes. We need to develop systems of care within the hospital that will allow us to achieve these times,” Jovin stressed.
According to a secondary analysis from REVASCAT presented at the European Stroke Organisation Conference (17–19 April, Glasgow, UK), somewhat surprisingly, the time from symptom onset to imaging does not correlate that much with treatment effect, but the workflow metric that is strongest correlated to outcome according to Jovin is the time from imaging to reperfusion. Nonetheless, a shorter time from onset to imaging translates into more patients meeting imaging criteria for treatment. In order to achieve faster onset-to-imaging and imaging-to-reperfusion times, Jovin suggested that centres should measure efficiency; engage the EMS providers and emergency department physicians; activate the interventional radiology (IR) teams as early as possible; minimise imaging to the minimum necessary; start the consent process early; avoid anaesthesia and intubation; and finally, minimise transport steps.
Jovin reported that based on all of these measures at his centre, the door-to-puncture time has been reduced from 103 minutes to 67 minutes and the puncture-to-reperfusion time has been reduced from 63 minutes to 47 minutes. He explained that at his centre, direct transfer patients (drip and ship) are now mostly taken straight to the angiosuite. In a series of patients treated using this paradigm, he said, median hospital door-to-groin puncture time was 15 minutes.
“I think ultimately the future is going to be some kind of imaging in the angiosuite. We should use collateral imaging to give us information about tissue viability—that would be a paradigm I would like to see being done more in the future. I do think that we need specialised stroke emergency departments with imaging. We need to get from the door-to-groin time of 90 minutes achieved in the most workflow efficient trial (ESCAPE) to 30 minutes. You will not be able to achieve this in every single patient, but you have to set metrics so that 80–90% of your patients can achieve a picture-to-puncture time of 30 minutes, a picture-to-reperfusion of 60 minutes, door-to-groin of 60 minutes, and door-to-reperfusion of 90 minutes,” Jovin maintained.
Concluding, he noted that these dramatic reductions in workflow times, improved treatments and consequent good clinical results can only be achieved in collaborative, multidisciplinary teams.