Abbas Kharal, MD, MPH, and Richa Sharma, MD, MPH

Wei D, Oxley TJ, Nistal DA, Mascitelli JR, Wilson N, Stein L, et al. Mobile Interventional Stroke Teams Lead to Faster Treatment Times for Thrombectomy in Large Vessel Occlusion. Stroke. 2017

This retrospective analysis of the expediency of Mobile Interventional Stroke Teams (MIST) in the treatment of acute ischemic stroke (AIS) patients with large vessel occlusions (LVO) introduces an interesting method of delivering acute stroke care in a densely populated urban setting. Contrary to previously adapted AIS treatment models of drip-and-ship (transfer of patients from PSC to CSC) and mothership (transfer directly to CSC while bypassing nearby PSC), the trip-and-treat model introduces the concept of transferring the interventional team — including a neurointerventionalist attending, fellow and radiological technologist — to the PSC where the patient presents. Patients were treated by the trip-and-treat model or the drip-and-ship model based on relative availability of operating rooms and neurosurgical intensive care unit beds at the peripheral hospital and CSC. Interestingly, mean initial door-to-puncture time was shorter in the trip-and-treat model compared to the historic drip-and-ship model {143 mins vs. 222 mins, respectively (P<0.0001)}. Although there was a trend in longer puncture-to-recanalization times for trip-and-treat (P=0.0887), initial door-to-recanalization was still 79 minutes faster for trip-and-treat.

The implications of this study are perhaps much more in a densely populated urban setting where many PSCs are combined with a CSC to form a stroke network within a short distance. In such cases, transferring of patients between two closely located hospitals can be very time consuming, as it requires multiple steps, i.e. time for pass off between health care teams including EMS, ED to ED transfer, documentation, OR arrangement, and preparation times. However, in these cases, perhaps MIST models may be more efficient in delivering reperfusion therapies without interrupting ongoing acute stroke and medical care at the PSC. Importantly, for a MIST model to work, each PSC needs to have technology and resources available to allow for reperfusion therapy to be delivered there. This model may be applicable only in suburban and rural hospitals which have the equipment for endovascular therapy and stroke care services, but lack endovascular personnel. The times from door-to groin-puncture were longer likely due to unfamiliarity and presence of uniplane angiography instead of biplane, the overall time from arrival to revascularization was shorter, highlighting the greater efficiency of this model.

Another downside of the drip-and-ship model is that the patient is transported away from their neighborhood hospital, thus requiring transplantation of his or her support system. This adds additional driving burden to the patient’s family and caregivers for visitation in the hospital and potentially at rehabilitation. The trip-and-treat model would allow the patient to remain in his or her community and prevent the interruption of care being provided not only from a stroke perspective, but by other subspecialties, rehabilitation, and case management.

The greatest controversy and confounding factor in this study was that firstly this was a non-randomized study and was retrospectively analyzed. Secondly, the acute stroke care centers involved in this study were all part of a preformed health network where the capabilities of delivering mobilized care in the form of MIST was doable. Thirdly, this study was performed in a very densely populated urban setting where there were 4 PSCs within 20 miles, which is not the case usually for other stroke networks; therefore, it is difficult to generalize such results to health networks where PSCs are usually more geographically separated. The authors themselves point out that there may have been a selection bias in the study, as patients in the 2 groups did not initially present to the same set of hospitals because patients treated by the trip-and-treat model presented to hospitals with endovascular capacity, whereas patients treated by the drip-and-ship model presented to hospitals with or without endovascular capacity. Additionally, excluding patients spending >4 hours in the initial hospital to avoid including in-hospital strokes may have unintended consequences. It is possible that patients are waiting for transport to arrive for >4 hours, which would potentially skew the results. Also, the authors did not adjust for the effect of time of day. One can imagine scenarios where traffic patterns at certain times of day would be prohibitive for the mobile stroke team to reach a PSC and sending the patient by ambulance may be faster to bypass traffic. Furthermore, it is conceivable that OR suites may be more readily available at certain times of day to accept endovascular patients, depending on the case volume of procedures at the institution.

A randomized controlled clinical trial of the trip-and-treat vs. drip-and-ship models is an intriguing area of research worth exploring. Given that many telestroke networks currently include spokes which are greater than 20 miles away, it would be interesting to include PSCs at greater distances accessible by both road and air transportation. Medical complexity, number of comorbidities, baseline functionality, and code status would be interesting factors to consider. Outcome measures such as rate of intracranial hemorrhage post-procedurally, discharge and follow-up functional status, as well as patient and family satisfaction, would be helpful to include. This study serves as a good foundation for such a trial in the future, but hopefully in a more generalizable setting.