Every year there are approximately 152,000 strokes in the UK. Most people affected are over 65, but anyone can have a stroke, including children. Stroke can have a huge effect on the patient and their family. There are many preventative and acute treatment strategies to help patients.
Professor Michael Hanna discusses how recent advances in acute stroke therapies have shown that acute clot removal therapies (thrombectomy) can increase good patient outcomes over and above that achieved with the established clot busting treatments (thrombolysis).
Professor Hanna also reviews the best ways to reduce the risk of having a stroke in the first place and the importance of multidisciplinary stroke rehabilitation.
Reorganisation of national stroke services has improved patient outcomes
A major development in the acute treatment of stroke in recent years has been the reorganisation of stroke services nationally. Reorganised stroke services has meant that a greater proportion of patients who develop symptoms of stroke can have rapid assessment at so called "hyper acute stroke units" and can be considered for clot busting treatment within 3-4.5 hours.
Many acute stroke patients who receive this treatment have better outcomes than patients who do not receive this treatment. However, it is also clear that despite receiving clot busting treatment some patients do not do well and clot busting treatment is not the best solution for all patients. Some patients may not be eligible for clot busting treatment if they have a history of previous brain haemorrhage or coagulation problems.
Recent new studies of "clot removal therapy" show promise
Recently, three new studies have provided important evidence that specialised techniques, known as "thrombectomy" or "endovascular treatment", a treatment process undertaken by radiologists, can significantly help certain patients.
Thombectomy is a process where the blood clot is removed from the artery in the brain by using a very fine tube (catheter device) which is usually inserted in an artery in the groin. The catheter is passed through the arterial tree to reach the relevant artery in the brain where it can "capture" and remove the blood clot.
One of the studies was termed "multicentre randomised clinical trial of endovascular treatment of acute ischaemic stroke in the Netherlands" (MR-CLEAN). It showed that patients who received the new thrombectomy treatment had significantly better outcomes (and less disability) than patients who had only the standard treatment. Two further studies by other international groups confirmed these benefits. One of the additional studies confirmed that thrombectomy combined with clot busting treatment was better than clot busting therapy alone.
These studies and the implications for clinical practice are summarised in a recent editorial in the Lancet:
What does this mean in clinical practice for patients with acute strokes?
The main implication of these new findings is that when patients present with acute strokes in hospital doctors should consider if they are eligible for acute clot removal therapy as well as clot busting therapy.
However, this has important implications for how acute stroke services are organised. It means that all acute stroke therapy centres must have a trained radiology team ready to undertake the procedure acutely. Such acute services are now being planned in stroke centres so patients can benefit from these new findings in the next 1-2years.
Professor Hanna discusses more about stroke and its prevention
What is a Stroke?
Stroke is also known as cerebrovascular accident (CVA) or cerebrovascular insult (CVI) is when the blood flow to part of the brain is acutely interrupted causing brain cell death and injury. There are two main types: ischemic due to lack of blood flow, and hemorrhagic due to bleeding. They result in part of the brain not functioning properly. Symptoms may include loss of ability to feel or move on one side of the body, problems understanding or speaking, dizziness, or loss of vision to one side among others. Symptoms usually come on very quickly.
If symptoms last less than 24 hours it is known as a transient ischemic attack (TIA). Hemorrhage strokes may also be associated with a severe headache. The symptoms and disability from a stroke can be permanent.
The main risk factors for stroke are high blood pressure, smoking, high blood cholesterol, obesity, lack of exercise, diabetes, previous TIA, heart valve disease and heart rhythm problems such as atrial fibrillation.
An ischemic stroke is typically caused by blockage of a blood vessel. A hemorrhagic stroke is caused by bleeding either directly into the brain or into the space surrounding the brain. Bleeding may occur due to a brain aneurysm.
Diagnosis, prevention and acute treatment of Stroke
Diagnosis is based on careful clinical assessment and physical examination followed by medical imaging such as an MRI scan. Other tests such as an electrocardiogram (ECG), carotid artery doppler scan, echocardiogram and blood test are done to determine risk factors and rule out other possible causes. Low blood sugar may cause similar symptoms to an acute stroke.
Prevention includes decreasing risk factors and may in some cases include surgery to open up the carotid arteries to the brain in those with narrowing, and warfarin in those with atrial fibrillation.
An acute stroke requires emergency care. An ischemic stroke, if detected within three to four and half hours may be treatable with a medication that can break down the clot (Thrombolysis). Aspirin should be used. Some hemorrhagic strokes benefit from surgery. Treatment to try to recover lost function is called stroke rehabilitation and ideally takes place in a stroke unit.
Hypertension accounts for 35-50% of stroke risk. Blood pressure reduction of 10 mmHg systolic or 5 mmHg diastolic reduces the risk of stroke by ~40%. Lowering blood pressure has been clearly shown to prevent both ischemic and hemorrhagic strokes. It is equally important in secondary prevention (ie preventing stroke recurrence in a patient who has had a stroke). Even patients older than 80 years and those with isolated systolic hypertension benefit from antihypertensive therapy.
Statins which lower cholesterol have been shown to reduce the risk of stroke by about 15%.
Diabetes mellitus increases the risk of stroke by 2 to 3 times.
Antiplatelet and Anticoagulation drugs
Several studies have shown that aspirin and antiplatelet drugs are highly effective in secondary prevention after a stroke or transient ischemic attack. Low doses of aspirin (for example 75–150 mg) are as effective as high doses but have fewer side effects. Thienopyridines (clopidogrel) are effective and have a decreased risk of gastrointestinal bleeding.
Patients with atrial fibrillation have a 5% a year risk of stroke, and this risk is higher in those with valvular atrial fibrillation. Depending on the stroke risk, anticoagulation with medications such as warfarin, new anticoagulant drugs (e.g. rivoroxaban) or aspirin is useful for prevention.
Nutrition, specifically the Mediterranean-style diet, has the potential for decreasing the risk of having a stroke significantly. Lowering levels of homocysteine with folic acid may affect the risk of stroke.
Carotid endarterectomy or carotid angioplasty can be used to remove atherosclerotic narrowing (stenosis) of the carotid artery. There is evidence supporting this procedure in selected cases. Endarterectomy for a significant stenosis has been shown to be useful in the prevention of further strokes in those who have already had one. Carotid artery stenting has not been shown to be equally useful. Patients are selected for surgery based on age, gender, degree of stenosis and time since symptoms. Surgery is most efficient when not delayed too long.
When an acute stroke is suspected by history and physical examination, the goal of early assessment is to determine the cause and if acute treatment is safe and appropriate. Acute stroke patients should all be admitted to a hyperacute stroke unit (HASU) where they are assessed for eligibility for acute treatments including thrombolysis or thrombectomy. After acute treatments, patients will be transferred to a "stroke unit". A stroke unit is a specialised dedicated area in hospital staffed by nurses and therapists with experience in stroke treatment. It has been shown that people admitted to a stroke unit have a higher chance of surviving than those admitted elsewhere in hospital.
Stroke rehabilitation is the process whereby patients undergo treatment to help them return to normal life as much as possible by regaining and relearning the skills of everyday living. It also aims to help patients adapt to difficulties, prevent secondary complications and educate family members to play a supporting role.
A rehabilitation team is multidisciplinary team involving staff with different skills working together to help the patient. The team includes neurological physicians, clinical pharmacists, nursing staff, physiotherapists, occupational therapists, speech and language therapists, and orthotists. Psychologists are also key members of the team since 30-40% of the people manifest post stroke depression. Good nursing care is fundamental in maintaining skin care, feeding, hydration, positioning, and monitoring vital signs such as temperature, pulse, and blood pressure. Stroke rehabilitation begins almost immediately.
Disability affects 75% of stroke survivors enough to decrease their employability. Stroke can affect people physically, mentally, emotionally, or a combination of the three. The results of stroke vary widely depending on size and location of the lesion. Dysfunctions correspond to areas in the brain that have been damaged. Rehabilitation programmes can significantly help patients and families.
More information for patients available at the stroke association website