vascular variation Flashcards
how does development of the heart and vascular system begin?
begins early in development in the mesoderm w/in (embryonic) and outside (extra embryonic, yolk sac and placental) the embryo
in early development how many aorta are there?
4:
2 dorsal aortae
2 ventral aortae
explain development of the venous system
embryological development of the venous system is complex
early in development vitalise veins (which drain the yolk sac) and umbilical veins form
what are the veins above the heart called?
pre cardinal veins (bilateral anterior veins)
- lee et al 2010
what are the veins below the heart called?
post cardinal veins (bilateral posterior veins)
- lee et al 2010
explain the developmental process of many veins that are singular in the adult
many veins that are singular in an adult go through a developmental process that involves the development of bilateral vessels first and then one regresses to leave the adult for
explain the development of the superior vena cava
the right cardinal veins form the superior vena cava
the left anterior cardinal vein should regress
what happens if the left anterior cardinal vein does not regress?
then there are 2 SVCs (duplication of the SVC)
what is the incidence of duplicated SVC?
very rare
explain the implication of a duplicated SVC
usually asymptomatic
venous variations are often asymptomatic because as long as the area is being drained and into the correct vessel then there are no blood flow issues and so no symptoms
explain the role of the 2 dorsal aortae in development
they communicate w/ the developing aortic sac and trunkus arterioles via 6 embryonic arches before the most posterior parts of the dorsal aortae fuse together to form one descending aorta
what doe the 4th embryonic arch from the dorsal aorta form?
the adult arch of the aorta on the left side
the right subclavian on the right side
what is chromosome 22q11 deletion assoc w/ and what is the reference?
chromosome 22q11 deletion is assoc w/ congenital heart disease but also w/ isolated conotrunchal anomalies
momma et al 1999
what were the findings of momma et al 1999?
that there is lots of variant anatomy possible when chromosome 22q11 is deleted but the heart retains normal textbook anatomy
where does the brachiocephalic artery form?
from the right horn of the aortic arch
what is the incidence of brachiocephalic artery variation?
it is rare
explain the study carried out by Iterezote et al (2009) on the branchiocephalic artery
study on 110 cadavers found 1 anomaly in the brachiocephalic trunk (0.9%)
the anomaly was brachiocephalic trunk 3.4cm long and 1.9cm in diameter lying infront of the trachea
explain the study carried out by Cromer et al (2004) on the brachiocephalic artery
highlighting the same variant as Iterezote et al (2009) but to the left of the aorta
lead to serious haemorrhage during percutaneous tracheotomy
67y/o female cadaver
what study discussed anomalous vessel compression and what were the findings?
De-Giogio et al (2011)
40y/o male, sudden death
anomalous origin of the right coronary artery lead to massive aneurysm that eventually burst and caused the death of the pt
where is the right coronary artery meant to originate from?
from the R aortic sinus
where did the right coronary artery arise from in the 40y/o male who died suddenly in De-Giorgio et al (2011)?
from the L aortic sinus and passed between the aortic and pulmonary valves
why did the origin of the right coronary artery cause the death of the 40y/o man in De-Giorgio et al (2011)?
because it passed between the aortic and pulmonary valves meaning it was compressed by the expansion of the valves and altered the haemodynamics leading to the formation of an aneurysm
why are variations of the IVC more common than variations of the SVC?
because the developmental process of the IVC is more complex than that of the SVC
what is the most common variation of the IVC?
duplication
what are the 3 types of IVC duplication?
type 1: same caliber trunks and pre aortic trunk
type 2: same caliber trunk but larger pre aortic trunk
type 3: asymmetric trunk, R IVC is the largest
what is the normal IVC anatomy?
1 IVC to the R of the aorta
what are the symptoms of IVC duplication and why?
asymptomatic because blood flow is not restricted
what are the findings of Hardwick et al (2011)?
interrupted IVC - blood was draining into a grossly swollen azygous vein
what is the prevalence of interruption of the IVC?
1:5000
what are the symptoms of IVC interruptions?
normally asymptomatic - the more extensive the interruption the more likely symptoms will be to manifest early
what are the findings of Kondo et al (2009)?
27 y/o man w/ 1 month history of painful swelling in both legs (DVT)
MRI found that there was an absence of the intra-hepatic IVC and the collateral circulation that communicates between the ascending lumber veins and the azygous system was attempting to compensate and becoming v enlarged in doing so
what is agenesis of the IVC?
the IVC does not form at all
what happens in agenesis of the IVC?
blood will find alternative routes back to the heart and so there will be enlargement of vessels
what are the findings of Gil et al (2006)?
14 y/o boy w/ mass in abdo and L leg DVT
found to have IVC agenesis and enlarged azygous and hemiazygous veins
what is the prevalence of agenesis of IVC?
up to 1% in the general population
up to 5% of young pts w/ DVT
what is the standard anatomy of the ascending lumbar vein?
it passes between the lumbar transverse process and psoas
what are the findings of Karcaaltincaba and Akata (2004)?
46 y/o man R lumbar vein passed through the foramen in the pedicle of L3 and mimicked the appearance of a lesion in the bone
the L lumbar vein was normal and the pt was asymptomatic
what is the standard anatomy of the renal arteries?
1 renal artery entering each kidney at the hilum
what is the incidence of people who have accessory / supernumerary renal arteries?
25% of people have 2-4 renal arteries
where do accessory / supernumerary renal arteries enter the kidney?
usually not at the hilum
usually at the poles
what is the importance of accessory / supernumerary arteries?
they are end arteries meaning that if they get blocked the area they supply will become ischaemic
how can accessory renal arteries cause hydronephrosis?
if they cross over the ureter they can obstruct it causing hydronephrosis
which paper reported the highly variable nature of the renal arteries and why is this a robust paper?
Ozkan et al (2006)
robust because of the large sample size (855 patients) and so likely to have found many of the variations present in the population
what are the issues regarding transplant and accessory renal arteries?
you must connect the donor and recipient vessels to successfully plumb in the kidney transplant
very anomalous and very short vessels are difficult to connect
2what were the findings of Yoo et al (2003)?
embryological vessel - persistent vitelline artery in 74 y/o woman
was silent until a loop of intestine became twisted around it and surgery was needed
why can vein patterns be used in biometrics?
because veins are formed during individual environment in developing tissue and therefore venous patterns are unique to each individual and so can reused for biometric authentication
what is the classic textbook description of the branching pattern of the common carotid arteries?
classic textbook description is that the only branches of the common carotid arteries are the terminal branches of the internal and external carotid arteries
how does the branching pattern of the common carotid arteries vary in real life compared to the classic textbook description?
several branches that normally arise form the external carotid artery may branch from the common carotid instead
which 5 arteries have been reported as branches from the common carotid artery?
lingual artery
superior thyroid artery
occipital artery
thyroid IMA artery
right vertebral artery
what are the findings of Anangwe et al (2008) in their study of the bifurcation of the common carotid artery?
they found that C3 is the most common vertebral level for bifurcation of the common carotid into the internal and external carotid
(C3-4 is the textbook bifurcation level)
bifurcation levels ranged from C2 to C6/7
how does agenesis of the internal carotid artery occur?
compression of the internal carotid artery during development leads to regression and agenesis of the internal carotid artery
what are the findings of Naeini et al (2005) in their report on agenesis of the internal carotid artery?
38y/o woman presented w/ right sided headaches but no neurological deficit
cerebral angiography revealed no R internal carotid artery which caused anomalous supply to the circle of wills on that side
what is the estimated prevalence of internal carotid artery agenesis?
<0.01%
agenesis of the internal carotid artery alters the origin of which artery?
the ophthalmic artery
what are the findings of Nathal et al (1992) in their circle of wills study?
intraoperative findings of 134 patients
found that the circle of willis was the most frequent site of cerebral aneurysms
there was an assoc between anomalies and cerebrovascular disease
what are the findings of Bugricourt et al (2009) in their circle of willis and migraine study?
investigated whether incomplete circle of willis is assoc w/ migraine
27 pts who had migraine w/out air
77 control pts
incomplete circle of willis in 49% of migraine pts and 18% of control pts
how common is duplication of the internal jugular vein?
very rare
Padres et al (2002) found 4 / 1000 unilateral neck dissections
when there is a duplicated internal jugular vein what finding is commonly seen?
an accessory nerve passing between the 2 sides of the vein
why may changes to the pathway of the internal jugular vein alter cause issues during lymph node clearance in the neck?
because the deep nodes cluster around the internal jugular vein
