While overlap exits in clinical presentation between ischemic and hemorrhagic stroke patients, embolic ischemic strokes are typically sudden and maximal at onset and correspond to the affected vascular territory, while intracerebral hemorrhage typically begins with symptoms such as headache developing into worsening focal deficits over minutes to hours.

Previous AHA / ASA guidelines for treatment of ischemic stroke with thrombolytics required an NIHSS of at least 4 as the treatment threshold. However, more recent guidelines from the AHA / ASA do not completely rule out thrombolytics for patients with low (NIHSS < 4) stroke scores. Instead the decision to treat with thrombolytics should be determined on the severity of symptoms and if those symptoms are disabling to the patient. 

Basic requirements for IV thrombolytic therapy include the absence of any absolute contraindications, a systolic blood pressure < 185

Last Known Well (LKW) < 3hrsAlteplase Aka tissue plasminogen activator (tPA), is the only thrombolytic approved for use in acute ischemic stroke patients by the FDA if presenting within 3hrs of symptom onset (last known well, LKW).

Last Known Well (LKW)  between 3 hrs - 4.5 hrs 

While currently not FDA approved for use in the USA up to 4.5 hrs after symptoms onset, thrombolysis with tPA is still recommended for appropriate candidates by the AHA / ASA. The inclusion criteria are similar to the < 3hr window, but includes an exception for patients > 80 years of age, patients on warfarin with INR < 1.7, and patients with known diabetes and prior stroke.

Review of inclusion and exclusion criteria can be reviewed elsewhere in the articles for further reading section. 

Icu Management 

ICU management for acute ischemic or post intervention stroke patients involves standard ICU care with special attention to parameters such as blood pressure control, additional head imaging,  initiation of secondary stroke prevention and DVT prophylaxis. 

1. Blood Pressure

• post tPA: Goal systolic BP < 180 / 105 mmHg. After 24hrs, may start reducing BP further

• No tPA: typically allow patient to autoregulate pressure up to systolic < 220 / 110mm Hg for first 24hrs before further reduction

• post NES intervention: optimal BP is variable depending on degree of recanalization and / or presence of intracranial stenting and is covered elsewhere

2. Additional Imaging 

• non-contrasted CT head / MRI Brain at 24 hrs post intervention (tpa / MT) 

3. Stroke Workup

   • all stroke patients in the ICU should have Hb A1c, B12, and Lipid Panel on admission.

4. Initiation of Secondary Stroke Prevention

   • secondary stroke prevention in most cases consists of the addition of antiplatelets after follow up imaging excludes hemorrhage or other complication

   • special considerations are given given to the timing of secondary stroke prevention (antiplatelet v anticoagulation) depending on the likely etiology, degree of clinical impairment, degree of radiographic stroke findings, as well as potential need for additonal interventions such as surgery. 

5. Nutrition

   • initiate early

6. DVT ppx

   • if 24-hour scan is negative, start DVT ppx

Mechanical thrombectomy should be a consideration for every ischemic stroke patient with a large vessel occlusion (LVO) involving the MCA, ICA, Basilar or vertebral arteries. 

Exclusion for MT include the absence of LVO or proximal LVO of CTA or large area of infarction already present on CTH imaging 

Evidence Supporting Mechanical Thrombectomy

Neuroendovascular techniques for ischemic stroke were born out of the need to expand the FDA approved 3hr treatment window for ischemic stroke and IV thrombolysis with tPA. 

2015 would usher in a new era in ischemic stroke intervention as 5 landmark trials for mechanical thrombectomy would be published and ultimately lead to this gold standard in acute ischemic stroke care.

An historical and contemporary review of endovascular therapy for acute ischemic stroke 

Degree of Revascularization:

Degree of revascularization with neuroendovascular intervention is graded with the Thrombolysis in cerebral infarction (TICI) scoring system. This scoring system is based on the  angiographic observation of blood flow immediately following the intervention.

TICI 0: no reperfusion 

TICI 1: minimal reperfusion

TICI 2a: partial filling, representing < 2/3rds of the entire vascular territory 

TICI 2b: complete refilling of the expected vascular territory but with slow filling

TICI 3: complete reperfusion