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-   -   CT Coronary Angiogram? (https://www.pprune.org/medical-health/602866-ct-coronary-angiogram.html)

noblues 7th Dec 2017 21:02

CT Coronary Angiogram?
 
I had some symptoms that possibly could have pointed towards a cardio issue of pains on my left side (shoulder, arm, and chest).

I was bounced off various consultants over a few month period by my GP, one of which was a Cardiologist who referred me for a CT Coronary Angiogram.

I held off having this scan as he thought from the description of my symptoms it 'was unlikely' to be cardio related and I wasn't keen on the radiation dosage if not 100% necessary. He said a CT Coronary Angiogram is the gold standard and would be 100% accurate.

I've now had an MRI of my neck which shows my C7 Disc has herniated and the spinal consultant thinks this the likely culprit for my issues.

I'm now in a major quandary if I should rule out any cardio risk?

My AME thinks it was unusual I wasn't given a stress ECG or echo before being referred for a CT Coronary Angiogram.

I'm worried about the radiation dosage if I don't really need the scan, but I am now thinking maybe I should clear my mind.
I have no family history of coronary heart disease.

cavortingcheetah 7th Dec 2017 21:40

As a patient, I believe very much in medical baselines when they serve a purpose of reassurance, yours or your specialists, in an otherwise slightly medical quandary. This might not be a view that is favoured by many on the medical side of the fence and that might be due in part because hypochondria walks hand in hand with medical paranoia. Nonetheless, when your livelihood is dependant upon that six monthly medical, it behoves one both to take care of the body and to be aware of any subtle internal changes of parameter that might presage something rotten this way coming.
The Mayo Clinic informs those interested that the risk of cancer caused by radiation from a CT coronary angiogram is small. There is of course no risk from radiation in a coronary angiogram but that might suit your requirements. The risk of death or life changing damage from a heart seizure or stroke might be greater?
There is one person on this forum who I am sure would be well able to answer your query. For my part, in the absence of specific medical advice, I'd take the non invasive procedure and have a definite answer to what seems to be a confused situation.

421dog 8th Dec 2017 01:04

A CT coronary angiogram does a good job of quantifying the amount of calcium present in your coronary vessels, but is no where near as good as traditional cardiac catheterization in terms of identifying (and allowing for treatment of) actual lesions.

There is an order of magnitude (at least) less radiation associated with a Gated Coronary CT than there is with the fluoroscopy required for an angiogram, even without intervention.

The quoted risk associated with a ct of that sort is something like a 0.05-0.1% increased lifetime risk of a malignancy (the baseline risk is on the order of 30% of ever getting cancer, so even at the high end, the CT would put you at 30.1% which ain't bad odds)

Some form of stress test (Bruce protocol, or some form of chemical stress test with a radioisotope or ultrasonic imaging) is a much better and safer screening tool in most circumstances.

Feel free to PM me if you have any questions.

Radgirl 8th Dec 2017 10:04

I would recommend you get your cardiologist to talk to your spinal surgeon. It is amazing how useful it is for 2 doctors to talk to each other. If your cardiologist then agrees there is no need for further investigation, and can appease your AME, all is sorted

If your cardiologist still believes there is a risk of coronary pathology, he can advise you which of the 3 tests to have - CTA, angiography or an exercise ECG. However, without further details angiography would rarely be the first test. I understand from my cardiology colleagues that for undiagnosed chest pain CTA is what is recommended by both the specialty and the NHS.

The radiation dose depends on the machine used. New machines have almost halved the dose in the last few years and quite frankly if your cardiologist feels it is clinically indicated I wouldnt give it a second thought. It will give you an unequivocal and immediate answer, and if there is an issue it may help you avoid an angiogram which apart from the much higher dose of radiation has other risks.

So I would agree with your cardiologist rather than your AME and reassure you the radiation on a new machine is irrelevant on a risk:benefit analysis

noblues 8th Dec 2017 12:11

Thanks for the replies:

My AME doesn't have an issue as the spinal consultant has written saying my symptoms are extremely likely due to my cervical disc herniation rather than anything cardiac.

I suppose personally I still have a small element of doubt!

I have been in touch with the radiologist who would do the CT Angiogram and has gone some way to reassure me about the radiation dosage which would be 3mSv. (Yes this used to be much higher with older machines).

To put that in perspective:
A dental X-ray is 0.005 mSv
A chest X-ray is 0.1 mSv

100mSv seems to be the recommended lifetime allowance, but having something blasting radiation at my heart muscle might well come back to haunt me in decades time.

421dog : Are you a cardiologist? Thanks for your other suggestions.

This is a quote from the radiologist who would do the scan:

I can understand your concerns with respect to radiation dose from the CT scan. At Paul Strickland Scanner Centre we use the latest CT scanner (Siemens Force dual source). Our average doses for cardiac CT scans range from 1.4 to 3 mSv. You can compare this with our natural background exposure of about 3 mSv every year, which we all receive. For someone in their middle age, the life time risk of cancer with a radiation dose of 5 mSv is about 1:4000. If you have a CT scan once a while (say once in 5 years), in my view the risk of getting any cancer during your life time from radiation itself is very low (except that one-third of us will die of a cancer any way- our natural risk, while 40% of us will die from cardiovascular disease).

Radgirl 8th Dec 2017 14:38

A milleSievert is a measurement of the amount of radiation absorbed so whether it hits your heart or anywhere else is irrelevant. The heart is made of muscle and far more resistant to the effects of radiation than many other tissues.

A healthcare worker is allowed to receive 50 mSv each and every year. Even looking at those people who have got close year after year for 40 years there is scant evidence of harm. Every long haul flight gives you 0.1 to 0.3 mSv. So you are worrying about a test that gives you the same exposure at perhaps only ten flights.

Everyone seems happy there is no risk of coronary issues so I would put the issue to bed and forget it. Should there be a problem you would most likely get a change of symptoms and we normally just send these people for a same day CTA. Most likely you will get no change, not have an issue, and fly for many years absorbing radiation with no consequences.

noblues 8th Dec 2017 17:46

Thanks Radgril, some interesting facts.

I didn't at first believe your quote of max 50mSv for health care workers, but see that is true in the UK. I find that unbelievable!

My father in his mid 40's during the late 1970's used to work in laboratories that made radioactive isotopes for medical use, he loved his job, the radiation levels were always monitored but invariably it was higher than someone who didn't work in that industry.

He got bowl cancer after 5yrs of doing that relatively young, luckily he survived but refused to go back in the laboratories.
In his early 80's he was very fit and healthy until out the blue he was diagnosed with a rare form of Leukaemia and was dead within six months.
Almost certainly that was from working with radiation 40yrs previously.

His best friend who did the same job had a string of cancers too ....

This is maybe why I am sooooo cautious over radiation, its like smoking a cigarette - Its not going to kill you now but years down the road who knows what the dice will throw ....

421dog 10th Dec 2017 00:00


421dog : Are you a cardiologist? Thanks for your other suggestions.
I am a general surgeon with a certificate of added qualification in critical care and also an FAA AME.

cavortingcheetah 10th Dec 2017 08:54

In the context of the OP raising the link between radiation exposure and cancers;
I don't think anyone has made a study of the thing but I do often wonder whether there is a correlation between flying older turbo prop airliners/aircraft for years at medium altitudes with their often less than efficient air filtration/conditioning systems and cancer.

Radgirl 10th Dec 2017 10:40

I dont want to hog this thread (nor I suspect do many of you!) and do not claim to be an expert but

noblues: the rules, regulations and monitoring have changed over the years. Lab work as opposed to clinical settings may well not have been so well monitored in the past. 50 mSv is not set as the edge of disaster but a totally safe level - in the rare instances where people go over they simply have to stay away from radiation for a time. I am not aware of occupational risk in healthcare workers who have now retired and for us younger ones!! the dose used continues to plummet. The latest generation of CT scanners for example use a third to a half less radiation than just 5 years ago

Cavortingcheetah: no I dont know the answer to your question, but a number of studies have failed to show any increase in cancers generally in pilots. The one exception is skin cancer which is increased but interestingly this may well be due to the effect of long haul on circadian rhythms.

Radiation is scary but the reality is that risk is tiny, and if radiation is needed for a medical test nowadays, on new equipment, I really wouldnt give it a second thought.

wiggy 10th Dec 2017 11:12

Radgirl will probably have the stats but the general cancer rates in the population are a bit horrible and often ignored....it's easier to focus on external factors that we think we can influence...I'll offer this as a FWIW:

Maternal Grandmother ( never flew..ever) died in the 1940s in her mid 40's from cancer.

Both of my parents died of cancer ( one pancreatic, the other bowel) before the age of each the age of 70, neither had ever flown for a living, probably been passengers for < 200 hours in their entire lifetime...

So despite over 40 years doing the day job I'm kind of reluctant to blame radiation for me winning the cancer bingo a couple of years back...third generation...what a surprise

I'm personally I think there's a lot to be said for the "healthy parents" theory and all that goes with it (but I know it's a theory that not many are keen on..)

noblues 10th Dec 2017 17:23

Maybe I am being way too sensitive to the risks of a CT scan, everything I read suggests dosages have as Radgirl says plummeted in recent years, and the benefits arguably outway the long term risk ....

A question I asked my radiologist was if they can tell me after the scan how much exposure I had, but he didn’t answer that! I can imagine their is a lot of skill to get accurate scans quickly with minimum repeats. But this thread is leading me to the conclusion that 1.5 to 3mSv of radiation exposure is insignificant.

I’m early 50s and one woud argue that I am more likely to keel over from a heart attack than die of a radiation related cancer in the next 30yrs.

I know several pilot colleagues who have had heart attacks, often fit and healthy individuals with no pre symptoms. I do sometimes question why years of Class 1 medical ECG testing can miss such a major killer, but gues its the nature of coronary heart disease.

obgraham 10th Dec 2017 17:33

We need to be careful and not draw general conclusions from specific cases. The fact that one's relatives had high incidences of cancer is not evidence that what they did for a living led to that cancer, or that the rest of us should avoid doing whatever he/she did.

Those "anecdotal" reports relate to individuals, not to populations at large.

I could choose the opposite approach: Harold McCluskey from my city absorbed the highest amount of Americium-241 in history from a nuclear production accident. He never developed any cancer, though he pee'd radioactive urine for years. Is that evidence that transuranic elements are not carcinogenic? -- of course not.

Qwikstop 28th Dec 2017 10:58

I think it's useful to consider the absolute risks of developing cancer from undergoing a CT. To put this in perspective the lifetime risk of dying from cancer is about 20%. A single CT, at a relatively high dose of 10 mSv, increases the average patient's risk of developing a fatal cancer from 20% to 20.05%.

With a modern scanner, slim patient and good heart rate control we can routinely get the radiation dose to under 2 mSv for a cardiac study (CTCA).

This is why NICE now recommend CTCA as the first line test for stable chest pain of suspected cardiac origin. No test is perfectly accurate but the negative predictive value (ie to rule out significant coronary artery disease) is around 99%.

noblues 28th Dec 2017 19:49

Thanks Qwikstop

The radiologist has quoted me 1.5 to 3 mSv for the cardio angiogram.

Do you know if they can tell me the exact exposure after the scan?

Do the CT machines have safeguards in place to avoid overdosing, say if a repeat scan was necessary due to patient factors like movement or too fast a heart beat?

I guess they must have to do initial setup scans for correct positioning, are these normally included in quoted mSV figures?

I'm warming towards having it done.

Qwikstop 28th Dec 2017 20:23

I wouldn’t get too fixated on the exact X-ray dose - but the range you give is typical. It will depend on a number of factors such as heart rate and body weight - as well as dose-reduction technology.

Alchemy101 28th Dec 2017 20:44

They won't know the exact dose delivered until the scan is done, only an estimate.

Scout films are relatively little exposure.

CTCA does involve a fair whack of radiation, albeit less than a dobutamine MIBI. 3mSv is about a 1 year's background dose at least here in Australia. A lot of doctors are pretty keen to run people through the scanner, (sometimes) myself included, but often it's worth thinking about. I agree with Qwikstop that the absolute risk of cancer is low, but there are other tissue effects from radiation that paradoxically increase vascular disease etc to contend with as well. Also, my perspective is different as I order about ~300 CT scans yearly so it doesn't take me much time to cause harm.

I woudn't rush to have it done if a stress test is normal and your pain best matches a proven cervical radiculopathy, unless the cardiologist thinks you still need it for other reasons.

I often find patients are enthusiastic about getting tests done because they want to 'just make sure everything is OK', not realising that the vast majority of tests are completely useless as screening tests because the uncertainty and harms from the tests themselves outweigh the benefits, and in a poorly selected patient a negative result doesn't reassure in any way.

That doesn't mean that the tests don't have utility, but you need to pick patients with a reasonable pre-test probability, and where the test will change your management. From what you have shared, your pre test probability is low now - but talk to your cardiologist.

noblues 29th Dec 2017 21:30

Thanks Alchemy101 and Qwikstop for those replies.

I read that Cardiac MRI's are getting a lot better with the obvious advantage of zero radiation, but it seems slightly ambiguous how good these are at seeing plaque build up in coronary arteries?

Qwikstop 30th Dec 2017 10:28

Cardiac MRI doesn't look at the coronary arteries directly (like CT), but is a functional test that assesses perfusion of the heart. Although there is no ionising radiation it does mean having an intravenous infusion, usually adenosine, as well as a simultaneous infusion of contrast medium. Asthma is a contraindication to adenosine, but otherwise it's a straightforward exam for most people.

It is usually considered in those with an intermediate pre-test probability of coronary artery disease or if the CTCA is non-diagnostic.

In general CTCA would be considered the first-line investigation in the UK for typical or atypical anginal chest pain, however in practice there is some variation depending on local expertise and availability.

Skip3662 26th Jul 2020 23:16

Follow up
 
Good morning, I understand this is an old thread, I am going through the same debate in my mind.

I’ve had intermittent left, pretty localised chest discomfort and in winter I get a both short of breath. EKG, 24hr Holter, Stress Echo = All OK. I’m only 38, no family history, no diabetes, I eat clean 90% of the time.

My cardiologist is not concerned and doesn’t recommend any further testing. BUT my GP has put doubt in my mind and said ‘why not have a CTCA it a reasonable thing to do’

Did you end up having the scan ?


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