Blood Vessels

vasa vasorum

the vascular network that feeds the arteries.

What are arteries enclosed by?

within sheath that includes vein, artery, & nerve.

tunica intima

the innermost layer of a blood vessel

tunica media

middle layer of artery; made up of smooth muscle fibers and thick layer of elastic connective tissue
thicker in arteries

tunica adventitia

The outer layer of tissue of a blood vessel wall, composed of elastic and fibrous connective tissue.
Contains vasa vasorum.

ascending aorta

Branches off the left ventricle; carries oxygen rich blood to parts of the body above the heart

descending aorta

the descending part of the aorta that branches into the thoracic and abdominal aortae

abdominal aorta

continuation of the thoracic aorta that runs through the abdominal cavity
starts when it exits the diaphragm

root of aorta

arises from the left ventricular outflow tract in the heart

brachiocephalic artery

The first major branch off of the aorta and the major artery to the forelimbs and head.

common carotid artery

Artery that supplies blood to the face, head, and neck.

subclavian artery

Both a left and right, blood vessels that supply blood to the shoulders and upper limbs.

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aortic valve

The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back into the left ventricle.

coronary arteries

blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle

2cm below diaphragm

Where is the celiac axis?

Left gastric artery, splenic artery, common hepatic artery

What are the branches of the CT?

Common hepatic artery

arises from the celiac trunk to supply the liver
splits into proper hepatic and gastroduodenal artery

mesenteric/splanchnic arteries

Numerous arteries that go into the remainder of the small and all of the large intestines; come off the dorsal aorta.
Celiac trunk, SMA, IMA , and branches.

mesenteric ischemia

An interruption of the blood supply to the mesentery.
Symptoms: post prandial pain, weight loss.

What are the branches of the SMA?

inferior panccreaticoduodenal
jejunal/ileal br.
ileocolic
right colic
middle colic

lymphadenopathy

disease of the lymph nodes
enlarged lymph nodes
appear as hypoechoic spots between the SMA and AO (in the longitudinal view)

renal arteries

The two branches of the abdominal aorta that supply the kidneys.
Arise from the lateral sides of the aorta.
Inferior to the SMA.

RRA (right renal artery)

Arises from the lateral wall of the aorta, travels posterior to the IVC to the supply the kidney. Longer than the LRA.

renal artery stenosis

renal artery narrowing due to atherosclerosis or other disease process.
abnormal blood flow to the kidneys can result in secondary hypertension.

secondary hypertension

high blood pressure due to kidney disease

arterial stents

devices placed in arteries, typically the iliac, aorta, renal, or coronary arteries, to open occluded vessels.

renal angiography

x-ray examination (with contrast) of the blood vessels of the kidney

What do you assess with an aortic sonogram?

Assess diameter, calcification (adenosclerosis), thrombus, or dissection

atheroma

fatty deposit within the wall of an artery

aneurysm

ballooning of a weakened portion of an arterial wall
permanent localized dilation of an artery, with an increase in
diameter of greater than 1.5 times normal diameter

aortic aneurysm

A weakness in the wall of the aorta that makes it susceptible to rupture
3cm or more in diameter

abdominal bruit

a wishing sound by stethoscope when placed over the abdominal aorta

What are patient symptoms for arterial pathology?

- pulsatile abdominal mass
- abdominal pain radiating to back
- abdominal bruit
- hemodynamic compromise in lower legs

Abdominal Aortic Aneurysm (AAA)

A condition in which the walls of the aorta in the abdomen weaken and blood leaks into the layers of the vessel, causing it to bulge.

aortic dissection

diagnosis in which the arterial wall splits apart

arteriovenous (AV) fistula

An abnormal communication between an artery and a vein. It can also be created surgically to provide access for hemodialysis.

arteriosclerosis

hardening of the artery walls

Atherosclerosis

condition in which fatty deposits called plaque build up on the inner walls of the arteries

What are risk factors for aneurysm?

atherosclerosis & arteriosclerosis (most common)
trauma
congenital defects
syphilis
mycosis
cystic medial nercrosis
inflammation
hypertension
too much blood

fusiform aneurysm

circumferential enlargement of a vessel with tapering at both ends

saccular aneurysm

a sac-like bulge on one side of an artery

Aneurysms <4cm

followed every 6 months
intervention if the patient becomes symptomatic

aneurysms 4-5cm

surgical intervention if the patient is in good health

aneurysms >5-6cm

may benefit from surgical repair, especially if patient has other risk factors

aneurysms >6-7cm

pose greatest risk of rupture; risk increases with age and other medical conditions

aortic dissection

vessel wall defect
high pressure blood splits aortic layers apart: hypertension, trauma, Marfan's syndrome
very dangerous and painful
three classifications

aortic dissection stage 1

rupture of intima

aortic dissection stage 2

dissection of media

aortic dissection stage 3

rupture of vessel

aortic dissection type 1

begins at aortic root- may extend through the entire length of the aortic arch *most dangerous

aortic dissection type II (Marfan's)

a complication of Marfan's syndrome. connective tissue in the aorta is damaged.

aortic dissection type III

aortic dissection starting in the descending aorta

false lumen

a blood-filled channel that forms in the wall of an artery, most commonly the aorta, during an aortic dissection

true lumen

the true or original channel within a vessel

aortic graft

a surgical repair of an aneursym, typically made from flexible material such as Teflon or Dacron.

Pseudoaneurysm

Blood escapes through a hole in the intima but is contained by deeper layers of the artery or adjacent tissue.

What causes pseudoaneurysm?

surgery or trauma

How to correct pseudoaneurysm?

Compression

What is different in the tunic media of a vein versus an artery?

Veins have a diminished tunica media with little elastic fiber or muscle fiber.

Right atrium of the heart

Where does the IVC deliver deoxygenated blood?

valsalva maneuver

A process that involves expiring against a closed windpipe, creating additional intra-abdominal pressure and spinal stability.

congestive heart failure

What disease causes backwards flow in the IVC due to lack of function in the right side of the heart?

Common iliac veins

What two veins come together to form the IVC?

Where is the IVC?

Posterior to the liver, to the right of the spine

Right, middle, left hepatic veins

What are the three hepatic veins?

Four sections of the IVC

hepatic, prerenal, renal, postrenal

Right renal artery

What major artery runs behind the IVC?

Congenital anomalies in the IVC

Duplicated IVC
Missing sections (azygos veins will take over to get blood to the heart)

azygos vein

a vessel that drains blood from the chest wall and empties into the superior vena cava

What can cause a dilated IVC?

right ventricular failure
congestive heart failure
pregnancy: uterus compresses IVC
tumors or masses compress IVC

thrombosis

blood clot

IVC filters

tubular wire mesh that is implanted into the IVC to trap small emboli that may cause problems in the heart or lungs
-possible for it to migrate cranially or caudally and perforate IVC

LE DVT

Lower Extremity Deep Vein Thrombosis

Budd-Chiari

an occlusion in the IVC or hepatic vein
usually from a clot. can be congenital.

Left renal vein
Because left gonadal vein drains into it

Which renal vein is larger?
Why?

right hepatic vein

One of three main veins draining the liver via the IVC; drains the right lobe of the liver.

middle hepatic vein

One of three main veins draining the liver via the IVC; drains the caudate lobe.

left hepatic vein

One of three main veins draining the liver via the IVC; drains the left lobe.

hepatopetal

flow toward the liver

hepatofugal

flow away from the liver

how to identify hepatic veins

Thin Walls - not surrounded by bright
acoustic reflections
Drain Towards Diaphragm
Increase In Size Closer To Diaphragm
Move Blood Out (Hepatofugal) Of Liver

triphasic

vascular flow yielding three phases (hepatic veins)

hepatomegaly

enlargement of the liver

What causes dilated hepatic veins?

liver masses, hepatomegaly, IVC obstruction

splenic vein

- drains spleen, stomach, pancreas
- located posterior and superior to pancreas
- receives inferior mesenteric vein

inferior mesenteric vein

vein that drains most of the colon and dumps into the splenic vein

superior mesenteric vein

- drains small bowel and part of colon
- arises from the small bowel
- joins SV behind pancreas head

5-7cm

how long is the main portal vein?

esophageal, rectal, & superficial abdominal veins

what veins does the main portal vein anastomose with?

porta hepatis through lesser omentum

where the main portal vein enter the liver?

portal triad

a portal vein, hepatic artery, and bile duct in connective tissue sheath

left lobe and caudate lobe

what does the left portal vein supply?

coronary gastroesophageal shunting

Lower esophageal varices occur where esophageal branches of left gastric vein form anastomoses with branches of azygos and
hemiazygos veins in lower esophagus

paraumbilical vein

Appears as continuation of left portal vein and extends down anterior abdominal wall to umbilicus

Hemorrhoidal Anastomoses

Connections between superior and middle hemorrhoidal veins.

Retroperitoneal Anastomoses

-Vascular structures within the lesser omentum may cause thickening of the omentum, especially in children
-Small vessels may be seen around the pancreas
-Doppler is useful in distinguishing these

caput medusa

blood flows away from portal vein to superficial veins of anterior abdominal wall, then to SVC or IVC
"stone" appearing stomach

cavernous transformation of the portal vein

occurs when the native portal vein is thrombosed and myriads of collateral channels develop in the porta hepatis to bypass the occlusion

When do we use TIPS?

- advanced liver disease waiting on a transplant
- decompresses portal system

Transjugular Intrahepatic Portosystemic Shunt (TIPS)

using ultrasound to go through the jugular vein to the liver. creates a portocaval shunt between a portal vein and a vein that connects to the IVC.

why do we use Doppler in the abdomen?

- to detect blood flow
- blood flowing in the correct direction
- blood profile (resistance, plug, laminar, etc.)

why do we use color doppler in the abdomen?

helps locate vessels, get a quick perspective of blood flow, and aids in spectral doppler sample volume placement

why do we use spectral doppler in the abdomen?

more precise than color
gets accurate velocity
flow profile
flow direction (antegrade, retrograde)
flow characteristics (phases, pulses, damped, etc.)

laminar flow

a smooth pattern of flow

turbulent flow

Irregular flow with random variations in pressure.

SMA flow profile

high resistance before eating
low resistance after eating

Aorta flow profile

• Flow varies at different levels
• Proximal aorta has high systolic/low diastolic flow
• Distal demonstrates triphasic flow

celiac axis flow

-some spectral broadening
-unchanged after meals

hepatic artery flow

-spectral broadening
-crucial in heart transplants

splenic artery flow

-very turbulent flow pattern
-very prone to aneurysm

renal artery flow

-nonresistive
-spectral broadening

renal vein flow

- variable flow similar to inferior vena cava
- evaluate with transplants

inferior vena cava and hepatic vein flow

- varies with respiration
- flows above and below the baseline due to reflux from right atrium

portal vein flow

- hepatopetal flow
- continuous flow patterns, varies slightly with respiration

symptoms of IVC thrombosis

leg edema, low back pain, pelvic pain, gastrointestinal complaints, and renal and liver abnormalities.