TP 13312

•	Foreword
•	Section 1
•	Section 2
•	Neurology
•	Cardiovascular
•	Diabetes
•	Asthma
•	Other Policies
•	Contacts
•	Alternate Formats

Stroke and Transient Ischemic Attack (TIA)

• General
• Modifying Considerations
• Transient Ischaemic Attacks
• Lacunes
• Cerebral Venous Thromosis
• Pregnancy in Stroke
• Asymptomatic Stenosis
• Arterial Dissections
• Ruptured Aneurysms
• Arterio Venous Malformations
• Cavernomas

General

Stroke is the third most common cause of death and a leading cause of disability in Canada. The risk of a recurrent stroke following an initial TIA or stroke has been looked at in a number of trials of various antiplatelet medications. These studies show about an 8% per annum risk of recurrence and about 2-3% risk of a myocardial infarction. The probability of recurrence does depend on the number of risk factors present and the degree of carotid artery stenosis.
Blood pressure control, cholesterol control, antiplatelet medications and cessation of smoking have made significance inroads into reducing the risk of stroke. Surgery has been particularly successful in patients who have significant carotid stenosis. Nevertheless, despite these management techniques, the risk of recurrent stroke remains high. Therefore, the vast majority of applicants who have had a stroke, will remain permanently unfit. All applicants with stroke secondary to an intracerebal hemorrhage are permanently unfit.

Modifying Considerations

Transient Ischaemic Attacks

The applicant who has a TIA must be evaluated carefully as some will in reality be migraine without headache, seizures, vestibular dysfunction, failure of ocular fusion, multiple sclerosis, brain tumors, subdural hematoma, hypoglycemia or syncope. Risk factors have to be carefully evaluated including possible cardiac sources of embolus. Applicants with negative imaging of brain, neck and heart and with minimal other risk factors can be considered for medical certification at three years after the event. 

Lacunes

These are a specific symptom complex with an appropriate abnormality on neuroimaging ascribed to a lacune. The majority are secondary to small vessel occlusion, others may be secondary to an embolus of various possible origins. They pose two problems one is the risk of recurrent infarct which is significant and the second is the accumulation of lacunes without obvious symptomatology but leading to the insidious onset of dementia The majority of applicants with
lacunar infarcts are therefore unfit. Occasional individuals who never had significant deficits and who fully recovered may be considered on an individual basis. These individuals require extensive work-up, including carotid Doppler studies and
echocardiography. They need an MRI to show if there is evidence of significant lacunar disease. If the above investigations do not show significant pathology, the risk factors are controlled and if after four years, the MRI does not show any increase of lacunar disease, the applicant could be considered on an individual basis for medical certification. Applicants with multiple lacunes are a concern, as they may be developing dementia and are unfit. 

A patent foramen ovale should not be considered a risk factor for stroke according to recent trials, unless associated with an atrial septal aneurysm. 

Cerebral Venous Thrombosis

Approximately 70% of people who have venous thrombosis, have a clear predisposing factor, such as factor 5 Leiden deficiency, Protein C or S deficiency, anti-thrombin 3 deficiency, or, PGM deficiency, trauma, infection or dehydration, anovulents, pregnancy and Methylenedioxymetamphetamine (Ecstasy). If there is no evidence of an ongoing or recurrent risk, if there has been no evidence of epilepsy and if the person has no significant sequelae from the thrombosis, they can be considered medically fit two years after the event. 

Pregnancy in Stroke

During pregnancy and puerperium the risk of stroke is 44 per 100,000. The cause for this type of stroke must to be sought as often multiple factors predispose towards such strokes. One has to look particularly for thrombophilia, anti-phospholipid antibodies, dehydration, cardiac disease and dissection. In those individuals where there has been no significant sequelae, particularly no cognitive difficulties or history of epilepsy and if the etiology of their stroke is not going to be a recurrent or ongoing problem, then they could be considered fit two years after the event. 

Asymptomatic Stenosis

Applicants who are found to have an 80% or greater stenosis of the carotid artery are at increased risk of stroke , TIA or myocardial infarct. They are unfit. An endarterectomy will not resolve this problem, as they probably have other arteries significantly involved. 

Arterial Dissections

Arterial dissections are one of the most common causes of stroke in the young. Applicants who have had a good recovery, in which imaging does not show any evidence of cerebral infarction, who have had no evidence of epileptic seizures, can be considered for medical certification after two years. They need imaging to show good restitution of flow, with no evidence of aneurysm. There should be no evidence of having had a subarachnoid hemorrhage. There should be no predisposition to further dissections.

Ruptured Aneurysms

The majority of applicants who have had a subarachnoid hemorrhage are permanently unfit. There are occasional people who have been successfully treated, who had excellent recovery, and who have never had seizures. Those individuals in
which repeated angiography shows that the treatment has been successful can be considered for medical certification at two years. If they had an endovascular approach, an angiogram should be repeated yearly for two further years, to show that successful repair has been maintained. An EEG at two years should not show significant abnormalities and particularly no potentially epileptiform discharges. Those who have perimesencephalic bleeds with normal angiography, could be considered fit at one year if they have had an excellent recovery, as is usually the case. Those with asymptomatic intracranial aneurysms less than 10 mm can be considered as continuing to be medically fit.

Arterio Venous Malformations

Those who are asymptomatic usually have a risk of 2-4 % per year of hemorrhage. Those who have been previously symptomatic have a risk as high as 33% in the first year. Therefore those with arteriovenous malformations are permanently unfit.

Cavernomas

Applicants with cavernomas that are deep, with no evidence of previous hemorrhage may be considered fit, all others should be considered unfit.