Welcome back to Vascular Medicine – Advanced.
In this segment, we’re going to discuss
vascular malformations. Almost all of these
are congenital and they’re noticed in early
childhood. And indeed very few of these ever
come to the attention of an adult cardiologist
or an adult cardiac surgeon. They’re almost
always taken care of by pediatricians and
pediatric surgeons. We’ll go through the
various types though for completeness sake.
We’ll talk about the definition of the various
vascular malformations. We’ll talk about
the difference between hemangiomas and so-called
non-neoplastic – that is non-cancerous – vascular
malformations. And we’ll come up with some
So let’s start with the definition. Vascular
malformations are developmental abnormalities
of the vascular system. They involve systems
that can be shown as dilated capillaries,
as dilated venules or as dilated small arteries.
And the taxonomy – that is the classification
– differs depending upon which blood vessels
So here is the overall definitions and categorizations
of vascular malformations.
The most common are, as you see, hemangiomas.
These are often seen as we’ll talk in a
moment in young children. Often, they’re
noticed at birth. And they gradually involute
with time, that is they disappear. And they’re
Of the non-neoplastic vascular malformations
– that is the non-cancerous ones – there
are some that can actually cause quite severe
One can have an AV malformation. That is an
arterial venous connection in the brain that
leaks and bleeds and can cause strokes or
Another form of these non-neoplastic vascular
malformations is a cavernoma, which is a variety
of tangled blood vessels that’s fed by the
artery and the vein and usually a more discreet
lesion. These can also bleed often in the
brain and can also cause seizures and strokes.
One can have a variety of malformations of
the aorta in the chest. And we’ll talk about
how, in the embryonic development, there can
be residual arches that are only seen in embryonic
life and usually disappear in most people
but are retained in certain people. And then
we’ll talk a little bit about port wine
stains, which do persist into adult life and
are quite commonly seen and can be treated
as well if they’re a cosmetic problem.
So let’s start with the most benign one:
They are usually self-involuting. As I’ve
said before, that means they go away on their
own. They may have a little swelling over
them. They may grow for a while in early childhood
but then they go away. It occurs because of
abnormalities in the endothelial cells that
line the blood vessels. And it’s manifested
by an increase number of normal or slightly
abnormal vessels that are filled with blood
and therefore usually, since they occur in
the skin, they’re quite visible as you can
see from the cartoons here.
There are a number of different forms of hemangioma
depending upon which blood vessels are involved.
Many of them are just low flow. They don’t
actually contain very much blood at a high
velocity. They can involve just capillaries.
Interestingly they can involve lymphatics.
We’ll talk a bit about that in the next
lecture. Or they can involve veins or arteries.
The high-flow ones can be more of a clinical
problem because there’s a blood shunt which
can actually put a minor strain on the heart.
But these are often more symptomatic, the
combined arteriovenous AVMs. I’ll show you
some examples. And those often need to be
Very rare are combinations of capillaries
and hemangiomas, capillary and vein hemangiomas,
lymph vein hemangiomas, capillary lymph venous
hemangiomas. But these are very rare and
usually are not much trouble and also involute.
So the life cycle usually goes through three
phases. And you can see, by the way, the picture
to the right: a number of young children with
these hemangiomas on their face.
The first image of them is that they’re
seen as an erythematous – that is a red
– macular flat patch on the skin. And they
often change a little bit, deepening in colour
and grow a little faster than the growth of
the child. And most are seen by about 12 months
There’s a plateau phase where there’s
no growth lasting between generally 9 to 12
months in most children and then there’s
a slow process of involution. And most have
disappeared by age 5 to age 9.
I know my own daughter was born with a little
haemangioma on her thigh. And by age 2 or
3 it had disappeared. And that is almost always
the course with haemangiomas. They’re very
common. They’re very benign. Cosmetically,
they are of concern but they almost always
go away on their own.