• Stent

A study by Sheth et al1 has examined the safety and efficacy of thrombectomy for acute ischemic stroke (AIS) using the Solitaire stent retriever device for patients treated in the roll-in phase of the Solitaire With the Intention For Thrombectomy (SWIFT) trial. This is a well designed study aimed at determining the learning curve for operators who had not previously used Solitaire for the treatment of emergent large vessel occlusion (ELVO). The roll-in period entailed treatment of two patients with the Solitaire device, before proceeding to the randomized phase of the trial. This represented the first clinical use of the stent retriever for these operators. Compared with randomized patients, those treated with Solitaire in the roll-in period achieved equivalent rates of reperfusion (55% vs 61%), adverse events (13% vs 9%), and good neurological outcomes (63% vs 58%).1 The authors concluded that “thrombectomy in AIS using the Solitaire stent retriever device can be performed safely and effectively when used by experienced neurointerventionalists without previous experience with the device”.1

The publication of this article, somewhat fortuitously, coincided with the recent presentations of four large, overwhelmingly positive, acute endovascular stroke trials.2–5 Results from these trials will certainly change the landscape of acute stroke treatment moving forward. Understanding the conclusions stated by Sheth et al in the proper context of the investigators’ study design and methodology is of paramount importance. The authors’ conclusion, taken out of context, can be misleading. Enrolling investigators in the study were experienced neurointerventionalists. Study site criteria explicitly required previous experience with clinical research and mechanical thrombectomy procedures. All participating sites had proficiency with the Merci retriever prior to the study launch, having participated in the Merci or Multi-Merci clinical trials or having Merci devices on shelf, and an annual volume of ≥30 endovascular interventions for AIS.1 These were not only experienced neurointerventionalists, but also operators well versed in the management and treatment of AIS.

Previous studies have demonstrated that procedural volume is associated with outcome in facilities performing mechanical thrombectomy for AIS.6 Extrapolating the findings of the current study to proceduralists/interventionalists without neurological training is speculative and, potentially, dangerous. This assumption undermines the critical importance of the techniques specific to neurointerventional procedures and the knowledge of cerebrovascular anatomy, physiology, and the collateral circulation. The advent of graphite shafts and oversized heads on golf drivers does not enable us all to drive the ball 300 yards straight down the fairway. Nor does ownership of a Les Paul custom guitar translate to guitar solos that sound like those of Jimi Hendrix. Simply put, it is not solely the equipment, but also the specialized skill and knowledge of the operator.

This study clearly indicates that thrombectomy in ELVO using the Solitaire stent retriever device can be performed safely and effectively when used by experienced neurointerventionalists without previous experience with the device. The critical qualifier here is ‘experienced neurointerventionalists’. It is quite possible that operators could achieve favorable mechanical thrombectomy results without experience treating AIS or extensive prior experience with neurointerventional procedures, but that remains to be seen. The question was not posed, nor the hypothesis tested, in this study.

A total of 0.4% of AIS patients received endovascular therapy between 2004 and 2009.7 Should the positive results of the recent AIS studies published in the New England Journal of Medicine2–4 serve to substantially increase the number of patients presenting for endovascular thrombectomy, we as a society will need to insure that our supply of capable operators matches patient demand. This may be achieved through efficient systems of care, increased exposure to ELVO during residency and fellowship training, or mobilizing existing operators as members of stroke treatment teams. Also critical will be efforts to improve patient access to centers performing mechanical thrombectomy procedures, and decreasing time from stroke symptom onset to presentation/treatment.8 ,9

Sheth et al demonstrated a rapid learning curve for experienced neuroendovascular surgeons treating ELVO with the Solitaire stent retriever device. The data suggest that favorable mechanical thrombectomy results can be achieved without prior device experience. What must be remembered is the vast amount of neurointerventional ‘experience’ the operators had before ever using the device.