This is a controlled clinical trial among non thrombolysed acute ischemic stroke patients to determine the effects of three levels of arterial pressure on death and neurological disability. After the admission in the vascular unit of the Emergency Department the patients are randomized to maintain during the first 24h the Systolic Arterial Pressure in tree levels of pressure: 140 to 160 mmHg; 161 to 180 mmHg and 181 to 200 mmHg. The end point of the study is the Modified Rankin score and mortality in three month after the discharge.

To maintain the tree levels of systolic arterial pressure during de first 24h we will use one of the two strategies:1) infusion of 500 to 1000ml of saline solution and/or norepinephrine solution to increase de systolic pressure or 2) infusion of esmolol or nitroprussiate solution to decrease de pressure. Every patient will have a transcranial doppler study in the first 24h to measure the mean velocity of cerebral arteries.

Inclusion Criteria:

• Patients 18 years or older, with the first Acute Ischemic Stroke within the first 6 hours of the symptoms and not candidate to thrombolysis
• We will also include patients with previous Ischemic Stroke with Ranking score 0 or 1

Exclusion Criteria:

• Improuvment of the symptoms rapidly (in the first 15 min after admission)
• Seizures not related do the acute ischemic stroke
• Previous ischemic stroke in the last 6 weeks and with Ranking score > 1
• Haemorrhagic stroke
• Anticoagulation
• Hypoglycemia
• Shock
• Acute heart failure