Hello, I’m Joseph Alpert and I’m here to talk with you about anomalous coronary arteries.
Let’s start with a case. A 17-year-old boy who has no past medical history collapses at school
during a basketball game after an episode of chest pain. He gets CPR.
Fortunately, there’s an ambulatory defibrillator there which shocks him back to sinus rhythm
and he’s brought to the hospital.
On admission, the electrocardiogram and the blood troponin level
led to a diagnosis of non-ST elevation myocardial infarction and a coronary angiogram
was performed and it showed a congenital abnormality of the coronary circulation.
I’m gonna show you that in more detail a little later but indeed,
that is a – can be a cause of sudden death. Let’s look at the normal coronary anatomy first.
On the left hand side, you see the sort of the typical heart diagram
with the left vein coronary artery coming off the left aortic sinus.
Splitting, the left vein splits into the circumflex and the LAD
and then, the right coronary comes off of the right coronary sinus.
If you look on the right, you’ll see the little diagram of – the red is the aorta,
the blue is the pulmonary artery which is right next to the aorta and you can see the left vein,
the left circumflex and the LAD coming off the left coronary sinus
and the right coming off of the right coronary sinus.
There are a number of normal variants of the coronary tree.
In fact, I always say the coronary anatomy is like fingerprints.
Everybody is slightly different but most 90% of people
will have the so called right dominant system
in which the back of the heart is supplied by the right coronary artery.
A few percent will have a co-dominant system in which the back of the heart is supplied
by both the right coronary and the left circumflex
and less than 10% will have left dominant in which the back of the wall
is supplied by the left circumflex artery
and the right coronary is quite small, supplying a little bit of the septum and the right ventricle.
Coronary anomalies occur and some of them are of significance.
There can be abnormalities in number of the coronaries in their origin,
in the course that they take and the termination.
They can occur in about one to five percent of patients.
And fortunately, most of them are benign.
They do not cause problems as we –
but some do cause problems as we saw in our first case, the 17-year-old boy who had a cardiac arrest.
One would think, “Oh, well, let’s do exercise testing on these
and anybody who has an anomaly that’s important will show up as a positive exercise test
or we could do intravascular Doppler studies.
They’re unfortunately poorly predictive.
So, what are the malignant features?
And I’m gonna go over this with some more detail later in the talk.
When the – a coronary artery arises from the wrong sinus,
let’s say the right coronary arises from the left sinus,
often, the ostium or the opening of the coronary artery is slit-like.
Thus, setting up a situation where ischemia might occur.
Why is that?
Because the right coronary has to take a sharp bend to get back to its original location
to supply the back of the heart and the right ventricle and part of the septum
and you’ll see that in a diagram later on.
That’s also perhaps one of the reasons there’s a slit-like opening
is because the acute angle of take-off from the cusp area.
Sometimes, the arteries take an intramural course that is there within the myocardium.
So, when the myocardium squeezes, no blood-flow goes through the coronary.
And occasionally, when a coronary takes its origin from the wrong sinus,
it has to cross between the aorta and the pulmonary trunk.
With exercise, the pulmonary artery dilates, the aorta dilates a bit,
and they can squeeze the artery and cause ischemia.
So, let’s take a look at how coronary anomalies could affect perfusion of the heart muscle.
So, here are some benign ones first of all that are not associated with ischemia.
Most anomalies in fact, are like this. One can have a split right coronary.
One can have an ectopic right coronary from a different part of a cusp that it usually comes from.
One can have an ectopic right coronary from a left cusp in which there’s no slit-like origin
and there’s no ischemia.
If there is an anomalous coronary from the opposite sinus,
there can be the slit-like opening or the sharp turn that the coronary artery takes in its origin
and this can lead to narrowing of the artery with reduced blood flow to the myocardium.
There are also entities called coronary artery fistulas.
That’s where the artery connects to the veins, usually, to a whole network of huge little veins,
results in a left to right shunt that can be significant
and sometimes, has to be managed and can lead to ischemia.
And then, there are myocardial bridges in which a piece of the myocardium
goes over off in the midpoint of an artery, more commonly, the LAD artery
and then, the result is that when the heart contracts, that squeezes the artery and can cause ischemia.
The most dangerous ones, the ones where there’s definitely ischemia,
so called obligatory ischemia are the anomalous origin of a coronary artery from a pulmonary artery.
You can imagine why that’s not good.
Pulmonary artery has very low oxygen and you’re gonna send low oxygen blood down a coronary artery
or where there is actually a narrowing or a disappearance almost of the beginning of a coronary artery,
the ostial atresia or sever stenosis.
Those are most dangerous.
Now, there’ve been a number of catheterization series
and I’m gonna give you the results from a number that show these anomalies are not all that common.
Here’s one series.
There were about 1,686 patients out of a total of 126,595 cath patients
that were collected in a database who had coronary anomalies.
Of those anomalies, you’ll see of the almost 1,700 anomalies,
only a little less than 200 involved a coronary origin from the opposite sinus.
In other words, a dangerous situation.
So, you see, it’s a very small percentage of these anomalies and again, just to reiterate,
benign is when the left-circumflex arises from the right sinus or from the right coronary
or when there’s a separate LAD and circumflex ostia,
in other words, there’s two ostia in the left coronary cusp.
Those are benign.
Usually serious are the anomalous left coronary artery from the pulmonary artery
as I already talked about because you’re putting deoxygenated blood down a coronary
or an anomalous right coronary artery from the pulmonary artery,
also, a same problem, blue blood going down a coronary artery.
Large coronary artery fistula and we’re gonna look at an example of that later
and anomalous coronary artery from the opposite sinus of Valsalva.
So, the left vein or the LAD from the right sinus or the right coronary from the left sinus.
Again, where you have to make a sharp bend in the abnormal coronary
and often, has a slit-like orifice.
So, here’s our boy who we presented in the beginning here
and you’ll notice he has the left circumflex coming off of the right coronary ostium.
And, so, that’s why he had some ischemia and a cardiac arrest when he was playing basketball.
Now, here’s another series of 1,950 US patients with coronary anomalies
and you can see a lot of them are the benign ones.
Here’s the split RCA, 1.23%.
Ectopic right coronary from the right sinus, that is not – the sinus is not –
the origin’s not exactly in the right place in the sinus.
You have an ectopic RCA from the left sinus.
This can be dangerous, 0.92% of the total.
Fistula, about again, almost 0.9%. An absent left main coronary artery.
This can be benign in the sense that if the LAD
and the circumflex take off from their own orifices
and there’s no left main, that’s relatively benign.
Circumflex arising from the right sinus can be a problem but can be benign as well.
Left coronary artery arising from the right sinus, that’s often a real dangerous situation
with potential for ischemia but fortunately, only 0.15 of the percent of the original.
Low origin of the RCA, low down in the sinus or even in the aortic wall, that’s also benign,
and then, all the other anomalies also, not very common.
Let’s look now at where both coronary arteries arise from the same sinus of Valsalva,
a potentially dangerous situation.
Look at the diagram on the left.
You’ll see that both the right coronary and the left coronary are arising from the same sinus
which is the right sinus and you’ll notice the left has to take a very perilous course
in between the aorta and the pulmonary artery and during exercise when both those dilate;
you could see that the left main coronary could be squeezed and result in ischemia.
Another problem is when both coronary arteries arise from the left sinus of Valsalva.
Here, you notice the right coronary has to emerge and pass between the aorta
and the pulmonary artery, the same thing can happen.
Exercise results in dilation of the aorta and the pulmonary artery
and can squeeze the right coronary resulting in ischemia.
Now, this can be defined with a contrast CAT scan.
Here, you see an example of that, of both coronaries arising from one of the sinuses.
And, again, often, you will see the same picture at a time of catheterization.
Here, we see another CAT scan. Here, you see both coronaries arising from the left sinus of Valsalva
and you can see that the right coronary has had to take a very perilous course
in between the aorta and the pulmonary artery.
As we’ve said before a couple of times, the cause of ischemia is due either to a slit-like orifice
because of the sharp turn that the coronary has to take when it’s coming off the wrong cusp.
But also, there can be a chance where it can be squeezed between the aorta and the pulmonary artery.
And here, you can see examples where the artery has to go between the pulmonary artery
and the aorta, somewhat similar to the last one.
In this case, both of them are coming – both coronary arteries are coming off of the right coronary sinus.
And you can see where that could be the slit-like orifice or the compression of the artery
as it passes between the aorta and the pulmonary artery.
And, again, just to show you the rest of it, you see it on the other side.
Again, the slit-like orifice compresses the critical coronary artery.
How frequent is this?
Well, here’s another series of – they only found 301 patients out of 210,700 cardiac catheterizations.
Seventy-nine percent of the 301 were anomalous right from the left sinus.
Twenty-one percent of the 301 were anomalous left-vein from the right sinus.
The diagnosis is of course, by angiography as we’ve shown you or by cardiac CT with 3D and contrast.
MRI will also show them and, of course, unfortunately, sometimes, we find them in autopsy
which, of course, we’re not happy about.
Remember, the way it’s fixed is that an intramural segment in the wall of the aorta is unroofed
and connect both the ostia so that that takes care of the slit-like ostia.
CABG of coronary bypass has been tried but there’s problems with competitive flow
between the bypass and the original coronary, and, so, sometimes, the CABG doesn’t stay open.
It turns out interestingly that some patients with congenital heart disease will have coronary anomalies.
So, patients with tetralogy of Fallot, three to seven percent have an abnormal origin of the LAD artery
from the right coronary artery or the right coronary cusp when present.
The LAD usually travels anterior to the pulmonary outflow tract in that case
and that means that there could be possible damage
during tetralogy of Fallot surgical right ventricular outflow tract repair.
The congenital heart surgeons know about this.
They always wanna see a coronary angiogram beforehand to make sure they know where the LAD is.
And this kind of thing happens a lot in D and L transposition patients as well.
They can have very abnormal coronaries.
Let’s take another example.
Here’s a 20-year-old college student present to your clinic with symptoms of heart failure
which have been getting worse for the last year.
The review of symptoms was positive for exertional chest pain but he said,
“Oh, he’s had that for as long as he can remember. He just thought that was normal.”
And this is, of course, an anomalous coronary arising from the pulmonary artery
and not from the aorta and as we talked about before,
you’re gonna have blue blood now going down the coronary artery instead of red blood.
And so, it’s not surprising that the myocardium is ischemic.
If it’s untreated in the absence of a big collateral network,
most infants with this 95% die within the first year.
But if there’s a lot of extensive collateral blood flow, patients may survive into adulthood
and end up with ischemic cardiomyopathy and often, here’s an angiogram showing you the treatment.
Rather, the picture and the treatment is, of course, to take the coronary artery off the pulmonary artery
and implant it into the aorta.
And here’s, again, an angiogram showing that.
And, so, here’s another one.
Another one of these abnormalities.
This is a fistula where there’s an abnormal communication between a coronary artery
and either the cardiac chamber or a major vessel.
For example, sometimes, you can have an artery that doesn’t go into the myocardium
but actually opens up into the right atrium.
So, if all you’re doing is just shunting blood through the coronary artery to the right atrium,
sometimes, they will end up in a large venous plexus,
a collection of abnormal venous blood vessels and again, not supply the myocardium very well.
It’s usually the RCA that’s involved in about 50% of these cases.
They can become quite large and in fact, can create a very measureable large left to right shunt.
And you can demonstrate them, of course, with coronary arteriography which is the best method.
Sometimes, they’re seen by Echo, MRI, also shows them, and CT also shows them.
And then, you have to decide whether to close them. It can be controversial.
We consider closing them if there’s a big volume overload cuz of a big left to right shunt.
If there’s evidence of myocardial ischemia due to a coronary steal syndrome,
if there are arrhythmias, or if there’s unexplained left ventricular dysfunction.
And often, they can be closed using PCI methods to block the fistula and it degenerates once blocked.
So, the take home message for clinicians is the following.
Coronary anomalies are relatively common but they rarely cause any symptoms.
Almost all of them are benign. They can be divided into anomalies of origin, course, vessel wall,
and destination, and as I said, most of them cause no trouble.
They’re just found at coronary angiography as, “Oh, look at that, surprise.”
But it’s not dangerous.
It’s important to understand which anomalies can occur with congenital heart disease
and which anomalies can be dangerous
because some of them can result in significant clinical consequences
including sudden death and many coronary anomalies are encountered just by chance,
fortuitously during routine coronary angiography.