Machi et al1 have recently published a clinical study in which they proved the effectiveness and safety of Solitaire FR in acute stroke. Retrievable stents allow a high recanalization rate, and have been associated with few complications and a good outcome.2 ,3 However, the etiology of stroke is heterogeneous and may affect the success of different recanalization techniques.4

We analyzed data from a prospective register of 88 consecutive patients with acute ischemic stroke treated with endovascular procedure in our center between 2009 and 2011. Patients presenting within the first 4.5 h of the onset of symptoms without contraindications for thrombolysis received intravenous tissue plasminogen activator (tPA), according to European guidelines in the management of acute stroke. If CT/MR angiography demonstrated large vessel occlusion, and no substantial neurological improvement was observed after tPA infusion, endovascular treatment was performed. Patients underwent endovascular procedures directly if intravenous tPA was contraindicated. Retrievable stents (mainly Solitaire FR) were the first choice treatment. Stroke etiology was classified according to the TOAST criteria5: atherothrombotic, cardioembolic, other etiology and unknown etiology. For statistical evaluation, χ² distribution, ANOVA and Kruskall–Wallis tests were used.

Data from a total of 88 patients were collected and the main characteristics and results are summarized in table 1. The most outstanding features of our study were the lack of effectiveness of retrievable stents in patients with atherothrombotic stroke compared with the other etiologies. Although retrievable stents were the first choice device, intrinsic characteristics of atherothrombotic lesions usually determined the need to use other devices. Retrievable stents were successfully used in 83.3% of cardioembolic stroke, but other devices (mainly carotid stents, self-expandable or balloon mounted intracranial stents and angioplasty) were necessary in all cases in the atherothrombotic group. Consequently, the procedure lasted longer in atherothrombotic stroke compared with the other groups (122 min (72–122) vs 72.5 min (31.5–107.5); p=0.023). However, there were no significant differences in recanalization rate. A trend towards a better recanalization result was seen in the non-atherothrombotic groups, but Thrombolysis in Cerebral Ischemia (TICI) scale <2a was 13.3%, 9.1%, 11.1% and 10.5% in the atherothrombotic, cardioembolic, other etiology and unknown groups, respectively. Mortality and outcome were different between the groups but other factors in addition to etiology could be involved.

In conclusion, our data show a high recanalization rate using retrievable stents, confirming the results previously described by Machi et al.1 However, our study suggests that the effectiveness of these devices may be conditioned by the etiology of stroke. Retrievable stents allow high recanalization and reperfusion rates, especially in cardioembolic stroke. When atherothrombosis is the main cause, other recanalization techniques (carotid autoexpandable stent, intracranial stent, angioplasty, among others)6 are frequently necessary.