Posts Tagged ‘screening’

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Carotid stenting sounds like a wonderful solution to the layperson.  But the truth is always more complicated.  I’ll talk about it more here to give a better understanding of the disease, diagnosis, and treatment options.

The carotid arteries

The carotid arteries (along with the vertebral arteries) bring blood to the brain. Plaque embolization (or flecks of plaque breaking off diseased or blocked arteries) is one of the main causes of embolic (or non-bleeding) strokes.  In people with blockages in this artery, treating or removing the plaque can prevent stroke.

Today we will talk about screening and diagnosis.. Next time: treatment options.

Detecting Carotid Stenosis:

These blockages can be detected with the use of a carotid doppler (or ultrasound) to listen to the speed of the blood (velocities) in the carotid artery and to visualize blockages.  Some blockages can also be heard on physical exam –  as a bruit (bru-ee) but this is not always a reliable indicator, as the most severe stenoses (or narrowing from plaque) usually don’t have a bruit.

Results are reported as a range – and this decides treatment options.  Generally, in people that have NOT had a stroke – surgical treatment is not advised until the blockage is 70 – 80% blocked.  This is because the risk of stroke increases with the amount of blockage, as the speed of the blood increases to pass through the narrowed space.  (Picture a garden hose, now put your thumb over the end, covering most of it and make the water shoot out – that’s what we mean by increased velocity.)

If you have had a stroke or mini stroke from a plaque breaking off and travelling to the small vessels of the brain, the doctors will usually operate with lesser blockages – because you have already demonstrated a tendency to have pieces break off.

Now this is important – strokes usually happen because of high grade (70 or higher stenosis) not occlusions (or 100% blockages).  That’s because there is more than one vessel bringing blood to the brain – (remember the vertebrals we mentioned earlier..)  Doctors do not undo occlusions because that actually increases the risk of stroke at the time of surgery.

If you have an occlusion – count yourself as lucky that you didn’t have a stroke when it was 99%  and worry about keeping the remaining vessels as clean as possible with medicines.

Screening for Carotid Stenosis:

Currently there are no screening guidelines for asymptomatic individuals.  Since symptomatic means the person has had a stroke or TIA (mini-stroke) knowing when to screen is important.

Generally screening should be done in people at high risk for developing accelerated plaque formation – and in people with vasculopathic disease history (people with a history of plaque or blockages other places.)

High risk for accelerated plaques:

1. Diabetes – diabetes accelerates plaque formation, which is why new guidelines suggest ALL people with Diabetes, regardless of blood cholesterol tests should be on a statin drug (simvastatin, rosuvastatin, lovastatin, atorvastatin, pravastatin)*

2. History of smoking – smoking causes similar effects inside blood vessels as diabetes.  As I explain to patients in the office, it makes plaque form faster by irritating blood vessels and making plaque more likely to stick.  This is also important when we talk about ‘medical management’ of plaque diseases.

Note: ‘Medical Management’ is a term that means exactly that – managing conditions (not curing or fixing) by use of medications.  The disease won’t go away but the thought is that medicines will slow the worsening of the conditioning.

People with history of vasculopathic disease:  these people should be screened because they already have a history of artery blockages – but people don’t always realize that carotid arteries and other arteries are essentially the same highway, so to speak.

This includes:

1. People with a history of Coronary artery disease (CAD) such as people with previous heart stents or bypass surgery.  In fact, one-third of people screened for carotid artery while awaiting bypass surgery (also called CABG) have significant carotid disease or stenosis.

2. People with blockages elsewhere: Renal artery stenosis (kidneys), peripheral artery disease (PAD) aka blockages in the legs, mesenteric artery disease (abdomen).

3. People with an abnormal eye exam or Amarosis fugax – this is basically a small stroke or mini-stroke to the eye.  Sometimes people develop symptoms (amarosis fugax – which is described as a sudden loss of vision, like a shade coming down over your eye).  Other times, the ophthalmologist sees a plaque in the artery to the eye on exam.

I’ll talk about more in my next post – and I am happy to answer condition related questions but not offer medical advice.  My legal eagles have a fit otherwise..

*as I have previously mentioned in Hidden Gem – it is vitally important patients know the generic names of their medications, along with dosages and administration information.


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