A stroke is a sudden problem causing loss of brain function. The commonest cause is due to blockage of the blood supply to the brain. The most common cause of stroke is furring up of the blood vessels, due to smoking, diabetes, high cholesterol etc. However in some people, more frequently if the stroke happens at a young age, the causes can be due to formation of a clot in the heart, or the veins in the legs.
This is when a clot forms in the legs, breaks off and travels in the circulation to the heart. In someone with a normal heart, a small clot will pass harmlessly to the lungs and will be filtered out there. If there is a “hole in the heart”, the clot can cross into the left side of the circulation (missing out the lung filter) and the clot can be pumped to the brain or other organ. If it goes to the brain and lodges in a small vessel it can cause a stroke, sometimes with catastrophic consequences. Some people are fortunate and have a small stroke or transient symptoms, sometimes called a TIA (transient ischaemic attack). In this case we usually offer closure of the hole (eg. PFO closure) or blood thinning with warfarin or a similar drug. Most people do not want to take blood thinners as these increase the risk of bleeding complications such as a bleed in the brain, which can also cause a stroke.
Atrial fibrillation and clot in the appendage
If people have a heart rhythm problem called atrial fibrillation (AF) then they can be at risk of stroke from a clot forming within a structure in the heart called the left atrial appendage (LAA). This is like the appendix, in that it is a finger-like structure that comes off the left atrium and has no clear purpose. Many people with AF have to take warfarin to prevent stroke in this case. For those that cannot take warfarin, or do not want to take warfarin, there is a keyhole procedure to block the appendage – LAA occlusion (LAAO), which has been shown to be better than taking warfarin after 4 years of follow up in a recent study. There are 2 devices to do this, the Watchman device and the Amplatzer Cardiac Plug. Dr Turner can offer this procedure at the Spire Hospital.
Assessing stroke risk
There are some population-based scoring systems to assess the stroke risk. However these can be refined by additional testing to look for AF, PFO and also to assess the LAA. Using transoesophageal echocardiography we can look for additional risk factors for stroke, not available with other techniques. This can refine decisions about the need for warfarin or LAAO and for some provide reassurance that the risk is not so high.