Aortic Dissection. What is it, and how is this condition mananged?

 

 

I received a telephone call here in Kuala Lumpur a few days ago from my eldest brother in Singapore  who together with my own relatives here in Malaysia and in Singapore who would normally consult me on their health problems. I shall not reveal my brother’s name for personal and ethical reasons, but I shall just address him here as ‘brother’.

I may also consider sharing out some medical cases for general discussions and updates  I normally encounter from many other patients, but they shall only  for educational purposes.  All patients’ names shall not be revealed as this is strictly for general medical information only.

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Dearest brother

I reviewed the results of your CT scan again a short while ago, and found you actually have what is called an “aortic dissection”.

What I explain here is just my personal opinion. You should also discuss what I mention here with your own vascular surgeon in Singapore.

Furthermore, your own son Lin Ming Shyue is a paediatrician and neonatologist, and your granddaughter is also a doctor, both in Singapore, with Anne Ann Ling Hsu our niece as a Senior Consultant Respiratory and Critical Care Physician in Singapore General Hospital. We also have so many of our relatives and their children who are also medical experts, medical and surgical consultants in Singapore, plus our youngest brother Lim Yew Cheng here in Gleneagles Hospital Kuala Lumpur who was a Professor of Surgery at the University Hospital, University of Malaya, and now a Senior Consultant Cardiothoracic Surgeon at Gleneagles, all of whom you should also seek their opinion. The more collective professional opinions the better.

However, since you have asked me, here’s my take on this is about your condition.

An aortic dissection can be serious as it may bust causing massive internal bleeding especially the blood will be flowing out from the aorta, the main artery in the body.

Let me explain a bit further.

There are three layers to the aortic wall. The inner wall or layer is called the tunica intima, the middle layer is called the tunica media, and the outer layer or wall is called the tunica adventitia.

Aortic dissection is the result from some tear in the aortic intima causing extravasation of blood into the aortic wall. This may result in aortic regurgitation and acute myocardial infarction, arrhythmias, haemopericardium, CVA, paraparesis, BP fluctuations in the extremities, bowel infarction and renal failure. 

The presentations are severe acute chest pains during onset, radiating to other areas. 

 Aortic dissection may be categorized according to DeBakey classification into

 1. Proximal to distal, from ascending aorta, arch down to the ascending aorta 

 2. Proximal, affects only the ascending aorta

 3. Distal, affects only the descending aorta, distal to left subclavian artery.

The urgent aim of treatment is to reduce systolic blood pressure to 100 to 120 mm Hg.

 The therapy of choice consists of giving IV nitroprusside combined with IV propranolol at 1 mg diluted in 5 ml of water every 5 minutes up to a maximum of 10 mg.

 Once BP is under control, surgery is considered for type 1 and type 2 

 Conservative treatment may be considered for type 3 aortic dissection. 

 

In your case, there was a tear between the inner intima and the middle media layer due to weakening of the walls of your aorta which is the main artery of your body. This weakening may be due to age as in your case, free radical damage, high blood pressure, or all 3 combined plus other causes as well.

 

The tear in the inner layer in your aorta caused the blood to enter between the inner and middle layers of the aorta to split (dissect) as shown in diagram from your CT scan. If the blood goes through the outside aortic wall, aortic dissection is often fatal as it will cause massive bleeding. However, in your case what I saw in the CT scan (I suppose it was a CT scan you showed without telling me further), the blood did not go any further into the tear along a long segment of your aorta. It stopped after a short segment. This may finally cause a blood clot to be formed in this area to block the blood from flowing any further into the segment between the intima and media (inner and middle walls of the aorta)  

 

In other words, the weakening of your aorta walls caused a tear in the intima and resulted in blood flowing between these two walls.  In other words, this caused blood to seep in between the walls of your aorta causing a bulge (aneurysm) there.  The weakening may also have caused that part of your aorta to bulge out like a balloon which your doctor there in Singapore initially reported as a pseudoaneurysm using ultrasound (Duplex ultrasound scan), but later confirmed it as a tear in the inner wall using CT scan.

 

A pseudoaneurysm is the result of an injury such as a tear to the blood vessel in your case. The artery then leaks out blood, which then pooled near the damaged spot. It's different from a true aneurysm, which happens when the wall of a blood vessel stretches and forms a bulge which may not necessarily bleed.  

 

As far as your question your doctor in Singapore wanted to follow up using CT  for you, I do not suggest that, because  it is NOT safe to use CT scans all the time as CT is actually x-rays, a prolonged exposure to this harmful radiation, often as long as 20 -30 minutes  which is not safe especially for your age, compared to ordinary x-rays that is just 1- 2 seconds of exposure.

 

CT scans means a computerized tomography that combines a series of X-ray images taken from different angles around your body and uses computer processing to create cross-sectional images (slices) of the bones, blood vessels and soft tissues inside your body. CT scan images provide more-detailed information than plain X-rays but are less sensitive than magnetic resonance imaging (MRI) that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body. MRI though much safer like ultrasound (ultrasonography such as Duplex) where harmful radiation is used in CT, it is more expensive.

Since we now know your case using a CT scan, is a tear in the inner lining of your aorta causing blood to flow between the intima and media, causing a pseudoaneurysm, I suggest you follow this up using only Duplex ultrasound to see if the bulge gets bigger over a short time. Initially, maybe you follow this up on a monthly basis for only 6 months, and if stable, follow it up only at a 3-month period, and if there is no further enlargement, follow it up 2 or 3 times more over a 6-month period.

 

If it is still stable, a yearly ultrasonography will suffice.  Then after a year, if it is still stable, you may do another CT scan (but much safer to use MRI) to see the condition of the tear and haemodynamic (blood flow) in that part of the lesion after a year.  

If during this period of monitoring, if the aneurysm becomes bigger which can easily be measured using the much cheaper and safer ultrasonography (Duplex), you can then consider using minimally invasive (keyhole) surgery (laparoscopy) to put a stent over that area to strengthen that part of the aortic wall. However, an aortic aneurysm stenting may also carry some risk of graft infection and possibly also narrowing of that part of the aorta (aortic stenosis) unless they use a drug-eluting stent which may only provide short-term solution after the anticoagulant drug is washed off by the continuous flow of blood through the main artery (aorta) of the body.  Here we may have another problem.

Furthermore, a clear patency benefit of a drug-eluting stent over bare metal stents for treating artery disease has not been definitively demonstrated.

In this surgical procedure, a cut is made in the upper thigh through which a catheter carrying the stent is inserted.  The stent graft is then guided using x-rays or by multi-detector CT Imaging through the arteries to the location of the aortic aneurysm. The stent graft is placed at the site and opened up.  Sometimes, they may use a fluoroscope which is also x-rays to guide the catheter in.  Whichever the procedure, you cannot avoid exposure to the radiation of x-rays.

Dye may then be injected into the blood after the stent graft is placed to make sure the entire procedure is in order and the stent is in place and working properly, and that blood is not leaking into the aneurysm. Injecting radiopaque dyes for x-ray monitoring itself is also not safe since your kidney functions are currently slightly below normal. Your blood creatinine and urea levels from the blood tests you showed me are slightly higher than normal, plus your glomerular filtration rate (GFR) is also lower than normal now. All these indicate your kidneys are less efficient now, and exposure to all these procedures may compromise your kidneys further.  The dye needs to be seen by X-rays which is yet another problem with the radio-opaque dye.

So, you need also to consider all these benefit / risk ratios for surgical options if the aneurysm becomes more pronounced on ultrasonographic measurements.

Aortic aneurysm besides aging is also linked to uncontrolled high blood pressure, and most common among elderly males.  If left untreated, the wall can fatally rupture which in the United States has 10,000 deaths annually. But I have no statistics in Singapore.

Consider all these first if you opt for surgery. But if I were you, I would just leave it and just monitor using Duplex ultrasonography.

Later, I shall find out if there are other alternative options such as the application of dietary and nutrition approaches to  strength the blood vessels from further damage or the use of botanical medicines such as the application of  yarrow, garlic, ginger, hawthorn,  Centella asiatica (Indian pennywort, pegaga, goto kola, etc), horse chestnuts, pine bark extracts, Butcher’s broom…etc, etc. that can support vascular health. But let me search the literature first to review studies done conclusively on these.  their dosages, period of application as much safer alternative therapeutic options.

Kindest regards,  

Your brother Lim ju boo