Stroke affects 26 million people annually globally, making it the second most common cause of death and a major contributor to long-term disability. One Two-thirds of strokes are caused by cerebral ischaemia, while one-third are caused by intracerebral or
subarachnoid haemorrhage. 1. Atherosclerosis in the cerebral circulation, blockage of cerebral small arteries, and cardiac embolism are some of the causes of ischaemic stroke. 2. Cardioembolic stroke is significant among these causes for two reasons. First, compared to other ischaemic stroke subtypes, cardiac embolism results in more severe strokes. 3. Second, in high-income nations like Canada, cardiac embolism has become a greater cause of strokes as the management of hypertension and dyslipidaemia advances. Since most cardioembolic strokes can be avoided, primary prevention measures for high-risk cardioembolic causes should be prioritised. Since most cardioembolic causes have a relatively high chance of reoccurring after a stroke caused by a cardiac embolism, secondary prophylaxis is also crucial.
Causes of Cardiogenic Embolic Stroke
Any cardiac insult that has the potential to fulfil the Virchow triad of endothelial damage, stasis, and hypercoagulability can result in cardioembolic strokes.
Typical causes include:1. Ventricular disorders, both structural and functional:- Ventricular aneurysms
- Septal aneurysms
- Heart failure characterised by a decreased ejection fraction, or general ventricular hypokinesia: Patients with heart failure with decreased ejection fraction (HFrEF) have an annual stroke rate of about 2%, and the degree of ventricular impairment is directly correlated with the risk of stroke.
2. Myocardial infarction: The incidence of myocardial infarction raises the risk of stroke, and the degree of risk is greatly influenced by the existence of arrhythmias, ventricular aneurysms or mural thrombus, and left ventricular dysfunction. Within the first four weeks of the infarction, about 2.5% of cases will experience a stroke, and over the course of six years, nearly 10% will. [expert_callback text="Book Online Consultation" buttontext="Request a Callback" link="]
3. Atrial disease:- Arrhythmias: The most common cause of cardioembolic strokes is thought to be atrial fibrillation, particularly non-valvular atrial fibrillation. [3] About 5% of those 65 and older experience this type of arrhythmia, which is thought to be the most common persistent arrhythmia. The majority of instances in western populations are thought to be due to hypertensive or ischaemic heart disease. Heavy drinking and hyperthyroidism are further contributing factors. There is a decrease in the number of cases with valvular heart disease, namely the involvement of the mitral valve. In terms of relative risk, however, those with valvular atrial fibrillation are 17 times more likely to experience a cardioembolic stroke than those without the condition, who are 2–7 times more likely to do so.
- Bradycardia-tachycardia syndrome, another name for sick sinus syndrome, is linked to a higher risk of stroke.
4. Valvular heart disease: This condition is associated with a higher risk of stroke even in the absence of arrhythmias. These consist of:
- Rheumatic mitral stenosis is the most prevalent type of rheumatic valvular illness. Stroke risk is extremely high in the absence of anticoagulation.
- About 10% of people who have infective endocarditis go on to have embolic strokes. Prior to starting antibiotic therapy or during the first two weeks of treatment, there is a higher chance of stroke. [4] Since anticoagulation is typically linked to superimposed microhemorrhages, it is contraindicated. Currently, anticoagulation should be started seven days following a stroke.
- Marantic endocarditis and other non-infectious endocarditis
- Valvular calcifications: The risk of having a cardioembolic stroke is increased by native valvular calcification, especially of the mitral valve. A relative risk of 2.1 for the occurrence of an embolic stroke is associated with mitral annular calcification. [6]
- Even in patients on oral anticoagulation, the stroke rate from mechanical prosthetic heart valves is between 2% and 4%. It is required to be on permanent anticoagulation with an INR of 2.5 to 3.5. Aspirin is advised unless the patient has atrial fibrillation, and bioprosthetic heart valves have a decreased risk of stroke.
- Anticoagulation is not advised in cases of mitral valve prolapse because the risk of stroke is low. On the other hand, long-term aspirin is advised.
Symptoms of Cardiogenic Embolic Stroke
There are many distinct clinical
symptoms of stroke. Sudden hemiparesis, hemisensory loss, disorientation, difficulties speaking, comprehension issues, vision loss, diplopia, ataxia, vertigo, or even an unexpectedly intense headache without a recognised reason can all be warning indicators of stroke. While some embolic strokes begin during rest or sleep, the majority of embolic occurrences take place during routine everyday activity. Other behaviours that are known to cause embolisms include sneezing, coughing suddenly, or getting up in the middle of the night to go to the toilet. In the Harvard Stroke Registry, 11% of patients with a cardioembolic stroke had a stuttering or stepwise course, while 10% exhibited fluctuations or increasing deficits, despite the fact that the deficit is usually highest at the beginning. If there is any later advancement, it usually starts within the first 48 hours. Transcranial Doppler (TCD) sonography has demonstrated a significant prevalence of acute MCA occlusion in patients with sudden-onset hemisphere strokes in recent years. The MCA does eventually recanalise, and the intracranial blood velocities return to normal.
The following are classic characteristics of cardioembolic stroke:- Sudden deterioration in mental health
- Shift in consciousness level
- Existence of neurological impairments
Treatment of Cardiogenic Embolic Stroke
The use of anticoagulants for secondary prevention is the cornerstone of treatment for cardioembolic strokes. The precise moment at which anticoagulation should be started is still up for debate, though. The aim is to achieve a careful equilibrium between the risk of a hemorrhagic change of the infarct and the risk of recurrence. [expert_callback text="Start Your Assessment" buttontext="Consult with Expert" link="https://medigence.com/appointment/book/vijita-jayan"]
1. According to current guidelines, which extrapolate from research based on heparin use, anticoagulation should be arbitrarily delayed for two weeks following the occurrence. Warfarin and other vitamin K antagonists are typically used for oral anticoagulation. Prothrombin time and the international normalised ratio (PT/INR) are serially assessed to track therapeutic response. The desired INR ranges from 2.0 to -3.0. For instances with metallic mitral valves, this goal is increased to 2.5 to 3.5. Despite being widely accessible and reasonably priced, these medicines' main disadvantages include a poorly predicted dose-response curve and a significant reliance on patient dietary compliance.
2. The new class of oral anticoagulants known as direct oral anticoagulants (DOACs) addresses the drawbacks of vitamin K antagonists. Apixaban, rivaroxaban, dabigatran, and edoxaban are among the agents that are available. The use of these more recent medicines eliminates the need for repeated monitoring and is thought to have a more predictable dose-response curve. The absence of a reversal agent was a major disadvantage of these DOACs, however this is no longer necessarily the case.
3. Another important strategy for preventing stroke recurrence is closing the patent foramen ovale. It has demonstrated non-inferiority to anticoagulation and a definite superiority to antiplatelet treatment. Patients under 60 years of age who have experienced a cardioembolic stroke should have their patent foramen ovale evaluated.
4. Patients who have recently had valve surgery or who have had an acute MI that required percutaneous coronary intervention may also experience a cardioembolic stroke. Although intravenous thrombolysis in this situation may result in surgical site haemorrhage, a few case series suggest that this event does not appear to have a significant impact on long-term results. However, when choosing to administer intravenous thrombolysis to postoperative patients, care must be taken because other bigger studies have discovered a connection between bleeding and exacerbated ischemia.
5. A number of devices, including the "WATCHMAN" device for left atrial appendage closure, have also been approved for the prevention of stroke. Patients with atrial fibrillation who cannot tolerate anticoagulation can benefit from such devices. These devices lower the risk of atrial thrombi, which arise from atrial fibrillation and emboli into the systemic circulation, by closing off the left atrial appendage.
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