What is an acute ischemic stroke?
Acute ischemic stroke is a major vascular complication with a high rate of mortality. This catastrophic medical emergency arises due to a sudden blockage of blood flow in the brain, accompanied by the loss of neurological functions.1 Thrombotic and embolic occlusions in cerebral arteries remain a prime cause of acute ischemic stroke.2 A blood clot (thrombus) inside the vascular pipeline is the result of the failure of blood clotting/dissolution process.3 Further, embolism refers to a blood clot that travels inside vascular pipelines and is capable of obstructing blood flow in vital tissues.4,5
Global burden of Acute Ischemic Stroke
The stroke incidence rate is high, with nearly 17 million strokes occurring each year. It is defined as the second leading cause of death worldwide. In the United States, 130,000 deaths per year are caused by acute ischemic strokes alone. Acute ischemic strokes are not only associated with a high mortality rate but also physical deformities and disability as well.6 Similarly, a large number of stroke cases (about 62,000) are reported each year in Canada.7 There is a high rate of acute ischemic stroke in Middle Eastern countries as well.8 A study published in Seminar in Neurology in 2018 states that there has been a massive rise in the incidence (6.9 million), prevalence (18 million), disability (47 million), and death (3.3 million) caused by ischemic stroke worldwide during 1990-2013.9
Risk factors for Acute Ischemic Stroke
Several risk factors associated with acute ischemic stroke have been studied, including traditional, genetic, and environmental. Traditional risk factors can be categorized into modifiable and nonmodifiable. Hypertension, diabetes mellitus, high blood cholesterol, cardiovascular diseases, lifestyle, atrial fibrillation, smoking, and consumption of alcohol are classified as modifiable risk factors. Meanwhile, age, gender, ethnicity, and genetics are nonmodifiable risk factors for stroke.10
There is increasing evidence for the involvement of several genes in acute ischemic stroke. Several studies have demonstrated that multiple genes are involved in acute ischemic stroke such as Apolipoprotein E (APOE), methylenetetrahydrofolate reductase (MTHFR), Endothelial Nitric Oxide Synthase (ENOS), Factor V Leiden (F5), Cytochrome P450 4F2 (CYP4F2), beta-fibrinogen, and Phosphodiesterase 4D (PDE4D)(10). Additionally, socioeconomic status has a serious impact on stroke: people with lower socioeconomic status have been reported to have higher risk factors for stroke, such as hypertension, hyperlipidemia, excessive alcohol intake, smoking, obesity, and sedentary lifestyle.11
Diet and acute ischemic stroke
Diet and nutrition are both closely associated with the risk of stroke. A healthy lifestyle reduces the risk of stroke by 80%. Several clinical trial studies have demonstrated that Mediterranean style diet and food are beneficial in reducing stroke risk. A diet rich in olive oil, whole grains, fruits, vegetables, and legumes and lowering the intake of cholesterol and saturated fat was found effective in reducing stroke risk. Further, dietary supplements including minerals (such as magnesium) and vitamins (such as B-vitamins) are beneficial in reducing the risk of stroke.12-14 Also, plant secondary metabolites—polyphenols—are effective natural compounds that offer protection against cardiovascular diseases.15
Therapeutics for acute ischemic stroke
There are several therapeutic approaches available to reduce the risk of life-threatening acute ischemic stroke. However, early diagnosis defines the effectiveness of any therapy. The diagnosis of acute ischemic stroke involves several modern techniques including brain imaging, CT angiography, magnetic resonance imaging (MRI), magnetic resonance angiography, and CT perfusion. Effective therapy includes intravenous thrombolysis using the recommended dose of external clot-dissolving protein—tissue plasminogen activator (tPA), and endovascular therapy.16 Additionally, mechanical thrombectomy, use of anticoagulants or antiplatelet agents could be recommended as treatment options for acute ischemic stroke caused by thrombotic blockage.17
Preventive measures and reversal of acute ischemic stroke
Avoidance of an acute ischemic stroke relies on preventive measures such as early detection and lifestyle management, especially if risk factors are present. Timely monitoring of risk factors delivers a great advantage in the prevention and reversal of acute ischemic stroke.18 Common symptoms of a stroke are motor, speech, and language impairment, problems with swallowing, vision, sensation, and cognition.6 One of the serious complications from this condition is cerebral edema (CED)—an increase of pressure in and around the brain. Endothelial dysfunction of capillaries associated with disruption of the blood-brain barrier (BBB) is a major cause of cerebral edema.19 Clinical uses of t-PA, which allows the clot to be dissolved so it may pass safely through the blood vessel, deliver an effective means for reversal and treatment of acute ischemic stroke.20
Certainly, seeking immediate medical intervention is critical to the successful reversal of acute ischemic stroke, but evidence also indicates that lifestyle choices, specifically diet, play an important role in reducing overall risk. High cholesterol is one major risk factor for acute ischemic stroke, hence a balanced diet with a high intake of whole grains, fruits and vegetables, legumes, olive oil and canola oil, and minimal use of hydrogenated oils (trans fats) is beneficial.21 According to the American Heart Association statistical report from 2015, the percentage of people consuming a healthy diet has decreased, and this might be a cause for higher acute ischemic stroke cases.22 Being overweight and/or obese both significantly alter plasma lipid profiles and may trigger a stroke. A healthy lifestyle, diet and exercise are beneficial in controlling body weight indirectly reducing the risk of acute ischemic stroke.
Recommended therapeutics such as thrombolytics are the first choice for acute ischemic stroke management; however, following preventive measures offer a significant benefit in stroke prevention:23-27