Timely and effective reperfusion is necessary to reverse the ischemic penumbra and to increase the chance of a favorable clinical outcome . Previously published studies suggested that mechanical treatment methods—particularly stenting in extracranial occlusions— achieve better recanalization, higher favorable outcome rates, and lower death rates than IAT only in patients with AIS resulting from occlusion of the ICA [14, 15]. Acute treatment for ischemic stroke has been rapidly evolving over the past 5 years resulting in a drastic improvement of functional outcome after ischemic stroke in selected patients .
The use of a post-procedural dual antiplatelet agent had a significant correlation (p = 0.008) with the outcome at 3 months: 78.8% of patients who underwent this treatment had a 90-day mRS of 0–2 vs 53.3% of those who used only one antiplatelet agent or heparin. This variable is also associated with good revascularization, in fact a TICI score 2B-3 was found in 90.9% of patients who received dual antiplatelet therapy vs 8% of those who did not (p = 0.001).
The choice of post-procedural antiplatelet therapy (single or double) was established as follows:
• Dual therapy: patient with stent implantation, a patient already on ASA therapy before the ischemic event but who nevertheless developed an AIS.
• Single therapy: a patient who was not implanted with a stent and who was not on ASA therapy before the ischemic event, patient with an indication for dual therapy but who developed a hemorrhagic transformation
• No therapy: Patient with single therapy indications who developed a hemorrhagic transformation
EVT can cause endothelial damage resulting in vessel stenosis, dissections and reocclusions [17, 18]. Antiplatelets might prevent thrombus formation and vessel reocclusion in damaged vessel. Furthermore, administration of antiplatelets is required to prevent reocclusion of stents [19, 20]. However, previous studies showed an increase in bleeding complications in bridging patients who receive additional antiplatelet therapy during endovascular intervention: The ARTIS trial was stopped early because of an increased rate of sICH in the patient group in which infusion of 300 mg aspirin was started within 90 minutes of intravenous thrombolysis with alteplase, with no improvement in outcome. 
Fisher et al. did not detect an increase in rates of sICH, aICH or any bleeding complications, neither in patients receiving aspirin acutely nor in patients pretreated with antiplatelets , in particular sICH (5.6% without ASA vs 6.1% with ASA) and aICH (20% without ASA vs 18.8% with ASA). This data supports our results: we found hemorrhagic transformation in only 19% of patients treated with antiplatelet agents after EVT (not distinguishing between single and double anti-aggregation). Furthermore, none of these hemorrhagic transformations manifested themselves with symptoms and just 1 patient had parenchymal hematoma type 2 (PH2) (> 30% of infarct zone, substantial mass effect attributable to the hematoma) who died before the follow-up at 3 months. Therefore, based on our experience, antiplatelet therapy after EVT is appropriate and safe. No comparison was possible between patients who received antiplatelet therapy and those who did not, since antiplatelet therapy was administered to all but 3 patients (2 were given LMWH and had no bleeding, 1 was not given any therapy and had H2 hemorrhagic transformation).
A similar result is found when evaluating the association between post-procedural hemorrhagic transformation and the outcome at 3 months. In fact, patients who did not present it have an mRS 0–2 at 3 months in 90.2% of cases vs 50% of those who presented it (p = 0.009). Similarly, patients who do not have hemorrhagic transformation have a TICI score 2B-3 in 90.2% of cases while only 50% of patients who present with post-procedural hemorrhage have a TICI score 2B-3.
A significant association is observed between 90-day mRS and the degree of vascularization obtained at the end of the treatment defined as successful intracranial recanalization (TICI 2B-3); in fact, 81% of patients who had a TICI 2B-3 had a 90 day MRS < 2 while none of the patients with a TICI of 0-2A had a 90-day mRS of 0–2 (p < 0.001). Furthermore, this factor affects the mortality rate, which was 2% in the first group and 33% in the second group (p = 0.015). This data is in accordance with a previous study which found a correlation between recanalization and outcome in acute ischemic stroke: recanalization is strongly associated with improved functional outcome and reduced mortality [19, 33].
In our study, we analyzed both patients with single ICA occlusion and patients who presented with TL, who underwent EVT. At 3 months a favorable outcome was achieved in 34 patients (67%), while a mRS > 2 was found in 13 patients (25%) and 4 patients did not survive, resulting in a mortality rate of 8%. These data are in accordance with a previous study  which found that the occurrence of recanalization is associated with a 4- to 5-fold increase in the odds of good final functional outcome and a 4- to 5-fold reduction in the odds of death.
Importantly, early NIHSS scores have a strong prognostic value for long-term functional outcome after stroke [23–24]. In fact, in all 4 cases of death, the pre-treatment NHISS was higher than 12. However, the strong correlation between NIHSS and mRS scores does not ensure that the NIHSS is a valid surrogate endpoint : we did not find a relevant correlation between the degree of severity on the NIHSS scale and MRS at 3 months: all patients who presented a “severe” NIHSS at discharge at 3 months had an mRS of 0–2.
Emergency carotid artery stent placement is expected to reopen an extracranial ICA occlusion with reduction of intracerebral blood flow in the affected hemisphere. Also, early flow restoration across the tandem lesion in the MCA and/or distal ICA after extracranial ICA stent placement would aim to reverse the ischemic process by stopping the expansion of the ischemic core into the penumbra. The use of stents certainly allows immediate flow restoration but also increases the technical complexity of the procedure. TICI 2B-3 was reported in 95% of patients in which a stent was deployed vs 73 % among those a stent was not employed (p = 0.064). Stents were used both on isolated ICA lesion and in TL, with a TICI 2B-3 of 100% in the first group and 94% in the second group. Therefore, stent placement led to a good angiographic result even in the TL group even though they have a less favorable prognosis.
In our study, antiplatelet therapy with a glycoprotein IIb / IIIa inhibitor immediately after stent release was used in 18 patients (35%). No acute stent thrombosis was observed while the occurrence of clinically symptomatic bleeding was 17% in patients who received antiplatelet therapy vs 21% in patients in whom it was not administered. Therefore, in our series this therapy was not associated with a greater risk of hemorrhagic transformation than in patients in which it was not used. Pre-treatment antiplatelet therapy was used in 21 patients (41%), of these 17 patients (81%) had a 90-day mRS 0–2 vs 57% among those who did not use antiplatelet therapy (p = 0.081). This result is in accordance with the study by Valente et al. who showed that prior use of antiplatelet therapy improves successful recanalization rate and does not increase the risk of intracranial bleeding in patients affected by AIS due to LVO and treated with EVT . In patients who received pre-treatment antiplatelet therapy, a TICI score of 2B-3 was found in 86% of patients, slightly higher than that found in patients in whom pre-treatment antiplatelet therapy was not administered (80%).
Among the comorbidities we have considered (diabetes, hypercholesterolemia, hypertension and atrial fibrillation) only atrial fibrillation showed a correlation with worse outcome with a trend towards significance. In fact, only 57.1% of patients with atrial fibrillation had a TICI score 2B-3 vs 86% of those who had not this condition (p = 0.095). Furthermore, considering the Outcome of mRS < 1 at 90 days, the presence of diabetes showed a trend towards significance. In fact, in patients not suffering from diabetes, 54.3% had an mRS < 1 while in the group of diabetic patients this value dropped to 25% (p = 0.07). This data contrasts with a previous study  which showed that the mRS score at discharge did not differ between patients with and without diabetes. There is, however, a paucity of studies that assessed the relationship between type 2 DM and functional outcome at discharge in acute ischemic stroke [28, 29, 30]. It is also relevant to note that 3 out of 4 patients who died before the 3-month follow-up belonged to the group of diabetic patients. Less impactful but still worth noting is that a TICI score of 2B-3 is found in 86% of patients without diabetes and in 75% of those affected by this disease, without however reaching statistical significance (p = 0.43). These data can be supported by the observation that diabetes, in addition to being a systemic pathology that affects the patient's performance, is also related to greater arteriosclerosis and stiffness of the vessels, that significantly affect endovascular technical difficulties.
There were no serious procedure-related complications such as dissection or vessel rupture in our study. Ten patients (19.6%) experienced post-procedural hemorrhagic transformation (all asymptomatic), without a significant increase in mortality.
Similarly to what was shown in a previous study  we observed a lower mortality rate in our series (8%) compared to Nedeltchev et al. (20%)  We hypothesize that the use of new devices in our study and technical advances that have occurred since the time of the study by Nedeltchev et al, such as mechanical clot disruption and the mechanical thrombectomy device, most likely contributed to this difference .
The present study had several limitations. First, it was observational retrospective, so it was prone to selection and other biases. Second, we used multiple thrombectomy techniques for the treatment of tandem occlusions, such as pharmacologic thrombolysis, mechanical clot disruption, or a mechanical thrombectomy device, making it difficult to determine the effect of the different techniques. Third, we did not have a control group with which to compare outcome rates. Last, since the main focus of this study is the treatment technique, we did not analyze perfusion imaging to quantify the ischemic area before revascularization.