Patients with tandem lesions (TL) are defined as patients with an acute ischemic stroke (AIS) with occlusion of an intracranial vessel of the anterior circulation and an occlusion or severe stenosis (70-99%) of the origin of the ipsilateral internal carotid artery (ICA). The greatest current limitation in the management of this type of lesion is the use of antithrombotic medication (double antiaggregation) in the acute phase that is required in case of placing extracranial stent to stabilize the atheroma plaque. In relation to this antiplatelet regimen, the latest clinical practice guidelines warn about the risk of combining intravenous fibrinolysis with antiplatelet medication in the acute phase, since it seems to increase the risk of symptomatic intracranial hemorrhage (sICH). However, the non-stabilization of the carotid atheroma plaque is associated with higher rates of cervical reocclusion, poorer functional prognosis, and higher mortality.

Therefore, the use of a single antiplatelet agent could be a reasonable alternative. To establish the best protocol for mono-antiaggregant therapy in the acute phase of TL, the investigators propose to carry out a prospective multicenter randomized clinical trial.

1. All patients with ischemic stroke secondary to TL in the anterior circulation candidates for mechanical thrombectomy in whom cervical endoprosthesis will be placed in the acute phase, will be included, randomized to two groups: 500 mg of intravenous (iv) Aspirin vs Low dose regimen of Tirofiban iv.
2. Carotid reocclusion rates and sICH rates will be evaluated within the first 24 hours after mechanical thrombectomy . As a secondary objective, the functional prognosis at 3 months in both groups will be analyzed, as well as a panel of biomarkers predictors of reocclusion in both groups. Establishing an antiplatelet management protocol in the acute phase in these patients would be an innovative strategy not developed by any other group worldwide, and would place us at the forefront of research in the field. Likewise, developing a clinical-biological predictive model of carotid reocclusion will allow us to establish risk patients in which to plan alternative treatments. Reference hospitals in the treatment of ischemic stroke at the national level with sufficient experience in the management of this pathology will participate in the project.

Inclusion Criteria:

• Patients with acute ischemic stroke of the anterior territory secondary to a tandem lesion, with an indication for thrombectomy treatment according to the current recommendations of the Clinical Practice Guidelines, and the need for cervical stent placement.
• The intracranial occlusion locations that may be included are: carotid "T", M1 and M2 segments of the middle cerebral artery, segment A1 of the anterior cerebral artery; and in the case that the posterior cerebral artery has fetal origin and is the site of intracranial occlusion.
• ASPECTS (Alberta Stroke Program Early computerized Tomography Score) ≥6.
• Greater than or equal to 18 years of age.
• Signed informed consent.

Exclusion Criteria:

• Patients under 18 years of age.
• Patients with ASPECTS <6.
• Bilateral strokes or those produced by simultaneous occlusion of an artery in the anterior and posterior territory.
• Patients whose carotid stenosis is due to a re-stenosis or reocclusion of a pre-existing cervical stent.
• Candidate patients for carotid puncture.
• Previous treatment with double antiplatelet therapy for another cause prior to inclusion.
• Severe comorbidity and / or reduced life expectancy.
• Modified Rankin scale (mRS)> 2.
• Severe allergy to contrast medium.
• Pregnant.
• Patients with intracranial occlusive arteriosclerotic disease or extra or intracranial dissection.
• Documented allergy to acetylsalicylic acid or Tirofiban.
• Personal history of platelet penia (Platelets <100,000)
• Concomitant anticoagulant treatment with presence of International Normalized Ratio (INR) > 1.7 in case of anti-vitamin K treatment or taking direct oral anticoagulant <48 hours ago)
• Medical history of the patient that carries a high risk of bleeding according to the investigator's criteria.