IR Flashcards
Puncture Needle sizes are designated by the
outer diameter
Catheter and Dilator sizes are designated by the
outer diameter
Sheaths are designated
by their
INNER lumen
size, (the maximum
capacity of a diameter
they can accommodate)
Puncture Needles
• The smaller the “gauge” number, the bigger the needle. It’s totally
counterintuitive. For example, an 8G Needle is much bigger than
a 16G Needle. *This is the opposite o f a “French, ” which is used
to describe the size o f a catheter or dilator. The larger the French,
the larger the catheter.
• The Gauge “G” refers to the OUTER diameter of the needle.
Wires:
Just some general terminology:
• 0.039 inch = 1mm
* 0.035 inch is the usual size for general purposes
• 0.018 and 0.014 are considered microwircs
* “Glide Wires” are hydrophilic coated wires that allow for easier passage of occlusions, stenosis, small or tortuous vessels.
Catheters - General
• 3 French = 1 mm (6 French = 2 mm, 9 French = 3 mm) Diameter in mm = Fr / 3
• Important trivia to understand is that the French size is the external diameter of a catheter (not the
caliber of the internal lumen).
• The standard 0.035 wire will f it through a 4F catheter (or larger)
Sheaths
• Sheaths arc used during cases that require exchange of multiple catheters. The sheath allows you to
change your catheters / wires without losing access.
• They are sized according to the largest catheter they will accommodate.
• The outer diameter of a vascular sheath is usually 1,5F to 2F larger than the inner lumen.
Sheath
simplified
Size is Given by INNER Diameter
Add 2 F for the Outer
Diameter (1F + 1F = 2F) if
you want to know how big
the hole in the skin will be.
- This would be a 6F Sheath
- The hole in the skin would be 8F
Gamesmanship
3 French
= 1 mm, so 1 French = 0.3 mm
Gamesmanship
Puncture Needles, Guide Wires, and Dilators are designated with sizes that describe their
outer diameters
Gamesmanship
Sheaths are designated with sizes that describe their
inner diameter
Gamesmanship
The rubber part o f the sheath is about
2F (0.6 mm) thick, so the hole in the skin is about 0.6mm bigger than the size o f the sheath.
Gamesmanship
Wire DIAMETERS are given in
INCHES (example “0.035 wire” is 0.035 inches thick)
Gamesmanship
Wire LENGTHS is typically given in
CENTIMETERS (example “ 180 wire” is 180 cm long)
Puncture Needles some conversions
- 16G n eedle has an outer diameter of 1.65 m m , = 5 F c a th e te r;
- 20G n e ed le has an o u te r d iam e te r o f 0 .9 7 m m , = 3 F cath
Some Needle Wire Rules:
Old School S e ld in g e r Technique
- 18G n e ed le will a c c ep t a 0.0 3 8 inch g u id ew ire
* 19G n e ed le will a llow a 0 .0 3 5 inch g u id ew ire
*Remember 0.035 is probably
the most common wire used. Thus the
19G is the standard needle in many 1R suites.
M icro P u n ctu r e Style
• Initial p u n c tu re is p e rfo rm ed w ith a 21G (ra th e r th an a ty p ic a l 18G o r 19G) n e ed le .
• 21G n e ed le will a llow a 0 .0 1 8 inch g u id ew ire
• A fte r you have th a t tin y wire in , y o u can e x c h a n g e a few d ila to rs up to a stan d a rd
4 F -5 F sy stem with th e p o p u la r 0 .0 3 5 wire.
Micro Puncture is Good when
- Access is tough (example = a fucking antegrade femoral puncture)
- You suck (“lack experience”)
- Anatomically sensitive areas (internal jugular, dialysis access)
Micro Puncture is Bad when
• Scarred Up Groins
• Big Fat People
• When you try and upsize, sometimes that flimsy 0.018 wont give enough support for antegrade passage of a
dilator.
Non-Steerable guidewires
These are used as supportive rails for catheters. These are NOT for
negotiating stenosis or selecting branches
Steerable guidewires
These have different shaped tips that can be turned or flipped into tight spots.
Within this category is the “hydrophilic” coated which are used to fit into the tightest spots.
Hydrophilic Guidewires
overview
“Slippery when wet”. They are sticky when dry, and super slippery
when wet. At most academic institutions dropping one of these slippery strings on the floor
will result in “not meeting the milestone” and “additional training” (weekend PICC workups).
Hydrophilic Guidewires
next step quiestion 1
Could revolve around the need to “wipe the wire with a wet sponge
each time it is used.”
Hydrophilic Guidewires
next step quiestion 2
Pretty much any situation where you c an ’t get into a tight spot. This
could be a stenotic vessel, or even an abscess cavity.
Guidewire length
• Remember Diameter is in INCHES, Length is in CENTIMETERS
• 180 cm is the standard length
• 260 cm is the long one. These are used if you are working in the upper extremity (from a
groin access), working in the visceral circulation and need to exchange catheters, using a
guide cath that is longer than 90 cm, through-and-through situation (“body flossing”).
• Minimal guidewire length = length of catheter + length of the guidewire in the patient.
Guidewire floppy tips
A lot o f w ires have pointy ends and soft floppy ends. The floppy ends are
usually available in different sizes. The testable point is that the shorter the floppy part the greater the chance o f vessel dissection. For example, a 1 cm floppy tip has a greater risk of dissection compared to a 6 cm floppy tip. The practical tip is to choose a wire with a long floppy tip (unless you are trying to squeeze into a really tight spot).
Guidewire stiffness
classic
- Bentson (floppy tip) = Classic guidewire test for acute thrombus lysability
- Lunderquist (super stiff) = “The coat hanger.” This thing is pretty much only for aortic stent grafting.
- Hydrophilic = Trying to get into a tight spot. Yes a Bentson is also an option, but this is more likely the “read my mind” choice.
Guidewire stiffness
which is stiffer
Least to greatest
Noodle like- bentson
Normal - hydrophilic, standard 0.035 or j straight
supportive - stiff hyrophilic, heavy duty or j straight
stiff - flexfinder, amplatzer stiff or extra stiff, 0.018 platinum plus, v18 shapeale tip
hulk smash - lunderquist, backup meier
more stiff =
more dissection
Guidewire stiffness
trivia
Stiff guidewires should NEVER be steered through even the mildest o f curves. You
should always introduce them through a catheter (that was originally placed over a conventional guidewire).
J Tip Terminology
A “J Shaped” Tip supposedly has the advantages o f not digging up
plaque and o f missing branch vessels. Often you will see a number associated with the J
(example 3 mm, 5 mm, 10 mm, 15 mm e tc …). This number refers to the radius o f the
curve. Small curves miss small branch vessels, larger curves miss larger branch vessels. The
classic example is the 15mm curve that can be used to avoid the profunda femoris during the
dreaded arterial antegrade stick.
Catheters
The three numbers that you are going to see on the package are
the outer diameter size (in
French), the inner diameter size (in INCHES), and the length (in CENTIMETERS).
Remember that the outer diameter of a catheter defines it’s size (unlike the sheath which is
defined by the inner diameter), and that these sizes are given in French. 4F catheters are very
commonly used. 110 and 0.035 are not catheter sizes available for humans existing outside of
middle earth.
Remember that length of the catheter is given in centimeters. The standard lengths vary from
about 45 cm to 125 centimeters.
Lastly the inner diameter of a catheter is given in inches and will pair up with the size wire.
For example, the largest wire a 0.035 catheter will accommodate is a 0.035.
Non-Selective Catheters
These things are used to inject contrast into medium and large shaped vessels. This is why y o u ” ll hear them called “flush catheters.”
pigtail and straight
Selective Catheters
These things come in a bunch o f different shapes/angles with the
goal o f “selecting” a branch vessel (as the name would imply).
Endhole only, side + endholes
Pigtail catheter
For larger vessels this is the main workhorse. It’s called a “pigtail” because the
distal end curls up as you retract the wire. This curled morphology keeps it out o f small
branch vessels. The catheter has both side and end holes.
Q: What might happen if you consistently inject through the pigtail like a pussy?
A: All the contrast will go out the proximal side holes and not the tip. Eventually, if
you keep flushing like a pansy you will end up with a clot on the tip.
Q: What should you do prior to giving it the full on alpha male injection ?
A: Give a small test injection to make sure you aren’t in or up against a small branch
vessel. Pigtails are for use in medium to large vessels.
Q: What if the pigtail fails to form as you retract the wire?
A: Push the catheter forward while twisting.
Straight catheter
This one doesn’t curl up as you retract the wire. Otherwise, it’s the same as a pigtail with side holes and an end hole. The utility o f this catheter is for smaller vessels (with the caveat that they still need decent flow).
The classic location is the iliac.
End Hole Only
Hand Injection Only
*high flow injection can displace the catheter, or cause dissection
Utility = Diagnostic Angiograms and
Embolization Procedures
Side + End Holes
Works fine with Pump Injected runs (can handle a rapid bolus without displacing)
Utility = Classic would be a SMA Angiogram
NEVER use with Embolotherapy.
The fucking coils can get trapped in the
sideholes or the particulate matter/mush may go out a side hole and go crush the wrong vessel. “Non-targeted” they call it.
What catheter
Acute Angle ( < 60)
Example = Aortic Arch Vessels
“Angled Tip Catheter”
Berenstein or Headhunter
What catheter
Angle of 60-120
Example = Renals, Maybe SMA and Celiac
“Curved Catheter”
“FtDC” Renal Double Curve,
or a “Cobra”
What catheter
Obtuse Angle ( > 120)
Example = Celiac, SMA, IMA
“Recurved”
Sidewinder (also called a Simmons), or a “Sos Omni”
WTF is a “Recurve” ?
For whatever reason Academic Angio guys tend to spaz if residents don’t
understand why a “recurve” is different than a regular curved catheter.
Basically any curved catheter has a “primary” curve and a “secondary” curve.
On a regular curved cath both are in the same direction. However, on a
recurved cath the primary goes one way, and the secondary goes the other.
These catheters are good for vessels with an obtuse angle. You pull the
catheter back to drop into them.
“Co-Axial Systems”
Basically one catheter inside another catheter/sheath. The most basic example would be a catheter inside the lumen of an arterial sheath.
“Guide Catheters”
These are large catheters meant to guide up to the desired vessel. Then you can swap them for something more conventional for distal catheterization.
“Introducer Guide”
This is another name for a long sheath.
“Microcatheter”
These are little (2-3 French). They are the weapon of choice for tiny vessels (example “super-selection” of peripheral or hepatic branches).
“Vascular Sheath”
a sheath (plastic tube) + hemostatic valve + side-arm for flushing
“Give me 20 fo r 30 ”
typical angio lingo for a run at 20cc/sec for a total o f 30cc.
How do yo u decide what the correct flow rate is ?
For the purpose o f multiple choice, I ’ll ju st say memorize the chart below. In real life you have to consider a bunch o f factors: catheter size, catheter pressure tolerance, flow dynamics, vessel size, volume o f the distal arterial bed (hand arteries can tolerate less blood displacement compared to something like the spleen), and interest in the venous system (a common concern in mesenteric angiography - hence the relatively increased volumes in the SMA, IMA, and Celiac on the chart).
Bigger Artery = Higher Rate
You want to try and displace 1/3 o f the blood per second to get
an adequate picture.
Rate 1-2mL/sec
Volume 4-10 mL
Bronchial Artery
Intercostal Artery
Rate 4-8mL/sec
Volume 8-15 mL
Carotid subclavian renal femoral IMA
*IMA are typically given a higher volumes (15-30ml)
Rate 5-7mL/sec
Volume 30-40 mL
Celiac
SMA
Rate 20-30mL/sec
Volume 30-40 mL
aorta
aortic arch
ivc
pulmonary artery
*abdominal aorta has a slightly lower rate (15-20ml/sec) as it is smaller htan the thoracic aorta
Maximum Flow Rates:
The se are de te rmined by the IN T ERN A L diame te r, length, and n umb e r o f size
holes. In general, each French size g iv e s you a b o u t 8ml/s.
These are the n umber s I would gues s i f forced to on multiple choice. In the real
world its (a) written on the pa ckage and (b) a range o f number s
3F = 8 ml/s , 4F = 16 ml/s , 5F = 24 ml/s.
Double Flush Technique
This is used in situations where even the smallest thrombus or air
bubble is going to fuck with someone’s go lf game (neuro 1R / cerebral angiograms). The
technique is to (1) aspirate the catheter until you get blood in the catheter, then (2) you attach
a new clean saline filled syringe and flush.
Single Flush Technique
This is used everywhere else (below the clavicles). The technique
is to (1) aspirate until you get about 1 drop o f blood in a saline filled syringe, and (2) tilt the
syringe 45 degrees and flush with saline only.
What i f you accidentally mixed the blood in with the saline?
Discard the syringe and double flush
What i f you are unable to aspirate any blood ?
Hopefully you are just jammed against a side wall. Try pulling back or manipulating the
catheter. If that doesn’t work then you have to assume you have a clot. In that case your
options are to (1) pull out and clear the clot outside the patient, or (2) blow the clot inside the
patient - you would only do this if you are embolizing that location anyway (and a few other
situations that are beyond the scope of this exam).
Arterial Access
you meet resistance as you thread the guidewire
next step = stop. resistance is an angio buzzword for something bad. pull hte wire out and confirm pulsatile flow. reposition the needle if necessary.
Arterial Access
You meet resistance as you thread the guidewire. Next Step = STOP! “Resistance” is an
angio buzzword for something
Next step = flatten the needle agaisnt the skin. you are asssuming the need to negotiate by a plaque.
Arterial Access
The wire stops after a short distance
nest step = look under fluoro to the confirm the carrect anatomic pathway. if it is normal you could put a 4F sheath in and inject some contrast. after that monkeying around with a hydrophilic wire is the ocnventional answer.
Femoral artery access
Femoral Artery Access - This is the most common arterial access route.
Anatomy review = the external iliac becomes the CFA after it gives o ff the inferior epigastric.
The ideal location is over the femoral head (which gives you something to compress against),
distal to the inguinal ligament / epigastric artery and proximal to the common femoral
bifurcation.
* If you stick too high (above inguinal ligament): You risk retroperitoneal bleed
* If you stick too low, you risk AV Fistula
* If you stick at the bifurcation: You risk occluding branching vessels with your sheath.
Brachial Access - Possible situations when you might want to do this:
- Femoral Artery is dead / unaccessible.
- The patient’s abdominal pannus, vagina, or ball sack is really stinky.
- Upper limb angioplasty is needed
Brachial Access
Special Testable Facts/Trivia
• Holding pressure is often difficult. Even a small hematoma can lead to medial brachial fascial compartment syndrome (cold fingers, weakness) - and is a surgical emergency which may require fasciotomy.
• The risk o f stroke is higher (relative to femoral access), if the catheter has to pass across the great vessels / arch.
• A sheath larger than a 7F may require a surgical cut down.
• The vessel is smaller and thus more prone to spasm. Some people like to give prophylactic
“GTN” - glyceryl trinitrate, to prevent spasm.
Brachial Access
Which arm ?
- Left Side if headed south (abdominal aorta or lower extremity).
- Right Side if headed north (thoracic aorta or cerebral vessels).
- All things equal = Left side (it’s usually non-dominant, and avoids the most cerebral vessels).
- Blood pressure difference greater than 20 Systolic suggest a stenosis (choose the other arm).
Radial Access
This is also a thing. There are two pieces o f trivia that I think are the most
testable about this access type.
(1) Bedrest is not required after compression.
(2) You need to perform an “Allen Test” prior to puncture. The “Allen Test” confirms
collateral flow via the ulnar artery to the hand (just in case you occlude the radial artery).
The test is done by manually compressing the radial and ulnar arteries. A pulse ox placed
on the middle finger should confirm desaturation. Then you release the ulnar artery and
saturation should improve, proving the ulnar artery is feeding the hand.
Translumbar Aortic Puncture
overview
This was more commonly performed in the dark ages / Cretaceous period. You still see them occasionally done during the full-on thrash that is the typical type 2 endoleak repair.
Translumbar Aortic Puncture
trivia
- The patient has to lay on his/her stomach (for hours!) during these horrible thrashes
- Hematoma o f the psoas happens pretty much every case, but is rarely symptomatic.
- Known supraceliac aortic aneurysm is a contraindication
- Typically “high” access - around the endplate of T12 - is done. Although you can technically go “low” - around L3.
- The patient “Self compresses” after the procedure by rolling over onto his/her back.
- Complaining about a “mild backache” occurs with literally every one of these cases because they all get a psoas hematoma.
arterial access pre procedure trivia
Prior to an arterial stick you have to know some anticoagulation
trivia.
• Stop the heparin 2 hours prior to procedure (PTT 1.2x o f control or less; normal 25-35 sec)
• INR o f 1.5 is the number I’d pick if asked (technically this is in flux)
• Stop Coumadin at least 5-7 days prior (vitamin K 25-50 mg IM 4 hours prior, or FFP/ Cryo)
• Platelet count should be > 50K (some texts say 75)
• Stop ASA/Plavix 5 days prior (according to SIR)
• Per the ACR - diagnostic angiography, routine angioplasty, and thrombolysis are considered “ clean procedures.” Therefore, antibiotic prophylaxis is unnecessary.
arterial access post procedure trivia
By the book, you want 15 minutes o f compression. You can typically pull a sheath with an ACT o f <150-180. Heparin can get turned back on 2 hours post (assuming no complications). Groin check and palpate pulses should be on the post procedure nursing orders.
Closure Devices
Never used if there is a question o f infection at the access site.
PICC lines
Use the non-dominant arm. The preference is basilic > brachial > cephalic.
You do n ‘t place these in patients with CRF, on dialysis, or maybe going to be on dialysis.
Central Lines/Port
The right IJ is preferred. External jugular veins can be used. Subclavian access is contraindicated in patients with a contraindication to PICC lines. Don’t place any tunneled lines/ports in septic patients (they get temporary lines).
National Kidney Foundation-Dialysis Outcome Quality Initiative (NKF-KDOQI)
Order o f preference for access: RIJ > LIJ > REJ > LEJ. “Fistula First Breakthrough I n i t i a t i v e is the reason you do n ’t place PICCs in dialysis patients.
What is the preferred access site fo r a dialysis catheter?
The right IJ is the preferred
access, because it is the shortest route to the preferred location (the cavoatrial junction). It will thrombose less than the subclavian (and even if it does, you d o n ’t lose drainage from the arm - like you would with a subclavian). Femoral approach is less desirable because the groin is a dirty dirty place.
Bleeding
hypotensions
The word “hypotension” in the clinical vignette after an arterial access should make you think about high sticks / retroperitoneal bleeds.
Bleeding
things that might help
• Placing an angioplasty balloon across the site o f the bleeding (or inflow) vessel.
Bleeding
applying pressure
- Where dat hole b e?
The hole in the skin and
the hole in the artery don’t
typically line up.
• Antegrade Puncture = Below the skin entry point
• Antegrade Puncture on a Fatty = Well Below the skin entry point
• Retrograde Puncture = Above the skin entry
Pseudoaneurysm Treatment
As described in the vascular chapter, you can get a pseudoaneurysm after a visit to the cardiology cath lab (or other rare causes). A lot o f the time, small ones (< 2 cm) will undergo spontaneous thrombosis. The ones that will typically
respond to interventional therapy are those with long narrow necks, and small defects. There are 3 main options for repair: (1) open surgery, (2) direct ultrasound compression, or (3) thrombin injection.
Pseudoaneurysm Treatment
next step
Pain disproportionate to that expected after a percutaneous stick = Get an US to look for a pseudoaneurysm
Pseudoaneurysm Treatment
direct compression
Direct compression o f the neck (if possible avoid compression o f the sac). Enough pressure should be applied to stop flow in the neck.
Painful for the Patient (and
the Radiologist), can take 20
mins to an hour.
Don’t compress if it’s above
the inguinal ligament.
Pseudoaneurysm Treatment
thrombin injection
Needle into apex o f cavity
(aim towards the inflow
defect) - inject 0.5-1.0 ml
(500-1000 units).
Do NOT aspirate blood into
syringe - will clot.
Contraindications: Local infection , Rapid Enlargement, Distal Limb Ischemia, Large Neck (risk for propagation), Pseudoaneurysm cavity size < 1cm.
Pseudoaneurysm Treatment
surgery
May be needed if thrombin injection fails, there is infection, there is tissue breakdown, or the aneurysm neck is too wide.
Pseudoaneurysm Treatment
Infected
Actively Bleeding No
Skin Necrosis
Thrombotic Event
Surgical
Pseudoaneurysm Treatment
Combined AV Fistula
Probably a covered stent
Pseudoaneurysm Treatment
Cavity size >2 cm and neck < 1cm
Thrombin, then repeat US in 2 days, if not better then repeat
Pseudoaneurysm Treatment
Cavity size >2 cm and neck > 1cm, if above the inguinal ligament
probably a covered stent
Pseudoaneurysm Treatment
Cavity size >2 cm and neck > 1cm, if below the inguinal ligament
compression with us, repeat us in 2 days and repeat if not improved.
*Might br worth a try but wide neck reduces the success rate.
Surgical *if the neck is very wide (15mm or more), you might consider going straight to surgery
Pseudoaneurysm Treatment
Cavity size < 2cm
repeat us in 1 week. if it got bigger then go to neck size algorithm.
Thrombin Injection - Where do you stick the needle ?
The needle should be placed
in the apex of the cavity (tip
directed towards the inflow defect).
Ultrasound Compression - Where do you compress ?
Orthogonal plane to the neck of the
pseudoaneurysm. Pressure is directed to obliterate flow in the neck / sac.
Pseudoaneurysm Treatment
Trivia
- Anticoagulation has no effect on thrombin injection treatment - primary success**
- Anticoagulation does* increase the risk of recurrence (10%?) after thrombin injection treatment
- Anticoagulation is NOT a contraindication to attempting direct compression, although it DOES reduce success rate and most people will tell you to stop them prior to the procedure (if possible).
- Failure to respond to thrombin = Occult vascular issue (big puncture site laceration, infection)
- Untreated Pseudoaneurysm for greater than 30 days tend to resist compression and thrombin therapy to variable degrees. They do best if treated within 2 weeks.
- Attempted compression of a Pseudoaneurysm above the inguinal ligament can cause a RP bleed. It is still safe to try and thrombin inject
General Tips/Trivia regarding angioplasty
The balloon should be big enough to take out
the stenosis and stretch the artery (slightly). The ideal balloon dilation is about 10-20% over
the normal artery diameter. Most IR guys/gals will claim success if the residual stenosis is
less than 30%. Obviously you want the patient anticoagulated, to avoid thrombosis after
intimal injury. The typical rule is 1-3 months o f anti-platelets (aspirin, clopidogrel) following
a stent.
“Primary Stenting”:
This is angioplasty first, then stent placement. You want to optimize
your result. Stenting after angioplasty usually gives a better result than ju st angioplasty alone
(with a few exceptions - notably FMD - to which stenting adds very little). An important
idea is that a stent c an ‘t do anything a balloon can’t. In other words, the stent w o n ‘t open it
any more than the balloon will, it ju st prevents recoil.
S e lf Expandable stents
good for areas that might get compressed (superficial locations).
• Classic Examples = Cervical Carotid or SFA.
Balloon Expandable stents
good for more precise deployment
• Classic Example = Renal ostium
Closed vs Open Cell Stents
Vascular stent designs may be categorized as (a) closed-cell -
where every stent segment is connected by a link (less flexible, with better radial force) or
(b) open-cell in which some stent segment connections are deliberately absent (flexible/
conforms to tortuous vessels, less radial force).
Nitinol (magic?):
Nitinol is said to have a “thermal memory.’’ It is soft at room temperature, but can become more rigid at body temperature. This is exploited for self expanding stents.
Drug Eluting Stents
These things have been used for CAD for a while. The purpose o f the “drug” is to retard neointimal hyperplasia.
Balloon Selection
Balloons should be 10-20% larger than the adjacent normal (non-stenotic) vessel diameter. A sneaky move would be to try and get you to measure a post-stenotic dilation.
As a general rule, larger balloons allow for more dilating force but the risk of exploding the vessel or creating a dissection is also increased.
Balloon Selection
artery size
Aorta -15 mm Common Iliac - 8mm External Iliac - 7mm CFA, Prox SFA - 6mm Distal SFA - 5mm
Stent Selection
Stents should be 1-2 cm longer than the stenosis and 1-2 mm wider than the unstenosed vessel lumen
You have more than 30% residual stenosis (failed you have).
The first thing to do (if possible) is to measure a pressure gradient. If there is no gradient across the lesion, you can still stop and claim victory. If there is a gradient you might be dealing with elastic recoil (the lesion disappeared with inflation, but reappeared after deflation). The next step in this case is to place a stent.
You can’t make the waist go away with balloon inflation
Switch balloons to either a higher pressure rated balloon, or a “cutting balloon.”
You caused a distal embolization
First do an angiographic run. If the limb / distal vessels look fine then you don’t need to intervene. If you threatened the limb, then obtain ipsilateral access and go after the clot (“aspiration”).
You exploded the vessel (“Extravasation”).
This is why you always leave the balloon on the wire after angioplasty. If you see extravasation get that balloon back in there quickly, and perform a low pressure insufflation proximal to the rupture to create tamponade. You may need to call vascular surgery (“the real doctors”).
What does dissection look like
spiraling
“ EVAR”
Endo Vascular abdominal aortic Aneurysm Repair. These include the bifurcated iliac systems and unilateral aortic + iliac systems.
“TEVAR”
Thoracic Endo Vascular aortic Aneurysm Repair.
THIS vs THAT: E n d o g r a fts VS Open Repair
- 30 Day Mortality is LESS for Endovascular Repair (like 30% less)
- Long Term Aneurysm Related Mortality (and total mortality) is the SAME for open vs endovascular repair
- Graft Related Complications and Re-interventions are HIGHER with Endovascular Repair
Indications for EVAR
(1) AAA larger than 5 cm (or more than 2x the size o f the normal aorta)
(2) AAA growing “rapidly” (more than 0.5 cm in 6 months)
Anatomy Criteria for EVAR
- Proximal landing zone must be:
- 10 mm long,
- Non- aneurysmal (less than 3.2 cm),
- Angled less than 60 degrees.
Stent Device Deployment
Tortuosity and Vessel Size are issues for device deployment. The general rules are that you have
problems if:
• Iliac vessels have an angulation > 90 degrees (especially if heavily calcified)
• Iliac artery diameters < 7 mm (may need a cut down and the placement o f a temporary conduit).
Absolute Contraindication to Infrarenal EVAR
Landing sites that won’t allow for aneurysm exclusion
Covering a critical artery (IMA in the setting o f known SMA and Celiac occlusion. Accessory renals that are feeding a horseshoe kidney, dominant lumbar arteries feeding the
cord).
Graft stents
Para-Rena
which is an umbrella term for aneurysms near the renals
Graft stents
“Juxta-Renal”
Aneurysm that has a “short neck” (proximal landing zone < 1 cm) or one that encroaches on the renals.
Graft stents
“S u pra-R enal”
Aneurysm that involves the renals and extends into the mesenteries.
Graft stents
“Crawford Type 4 Thoracoabdominal Aortic Aneurysm ”
Aneurysm that extends from the 12th intercostal space to the iliac bifurcation with involvement o f the origins o f the renal, superior mesenteric, and celiac arteries.
Stent graft complications
The most feared/dreaded (testable) complication o f an aortic stent graft is paraplegia secondary to cord ischemia. You see this most commonly when there is extensive coverage o f the aorta (specifically T9- T12 Adamkiewicz territory), or a previous AAA repair. “Beware o f the hair pinned turn” - famously refers to the morphology o f Adamkiewicz on angiogram.
Symptoms o f possible / developing paraplegia post procedure. Next Step = CSF d ra in a g e .
Adamkiewicz level
T9-T12
Celiac level
T12
SMA level
L1
Renal artery level
L 2
IMA level
L3
AAA pre / po st E n d o g ra ft
Type 1
Leak at the top (A) or the bottom (B) o f the graft. They are typically high
pressure and require intervention (or the sac will keep growing).
AAA pre / po st E n d o g ra ft
Type 2
Filling o f the sac via a feeder artery. This is the MOST COMMO N type,
and is usually seen after repair o f an abdominal aneurysm. The most likely culprits
are the IMA or a Lumbar artery. The majority spontaneously resolve, but some may
require treatment. Typically, you follow the sac size and if it grows you treat it.
AAA pre / po st E n d o g ra ft
Type 3
This is a defect/fracture in the graft. It is usually the result o f pieces not
overlapping.
AAA pre / po st E n d o g ra ft
Type 4
This is from porosity o f the graft. ( “4 is from the P o re”). It’s o f historic
significance, and doesn’t happen with modem grafts.
AAA pre / po st E n d o g ra ft
Type 5
This is endotension. It’s not a true leak and it may be due to pulsation o f the
graft wall. Some people d o n ’t believe in these, but I’ve seen them. They are real
AAA pre / po st E n d o g ra ft
Treatment
The endoleaks that must he emergently treated are the high flow ones - Type 1
an d Type 3. Most IR guys / vascular surgeons (real doctors) will watch a Type 2 for at least a
year (as long as it’s not enlarging). Most Type 4s will resolve within 48 hours o f device
implantation.
Embolization
Big > permanent
coils (lung AVM)
Embolization
Big > temporary
Gelfoam pledget (trauma)
Embolization
Small > permanent > Kill
liquid agent (RCC ablation)
Embolization
Small > permanent> wound
PArticles (fibroid embo)
Embolization
Small > temporary
Microshpere (cheo)
Mechanical embo
coilds
Vascular plugs ( amplatzer)
Particulate embo
pva - particles (permanenet)
Gelfoam (temporary)
Autologous (temporary)
Liquid agents embo
sclerosants
non-sclerosants
Coils
overview
These are typically used to permanently occlude a
large vessel. They come in all kinds o f different sizes
and shapes. You can deploy them with a “push” via a
coaxial system, or if you do n ’t need exact precision
you can “ chase” them with a saline bolus.
It gets complicated and beyond the scope o f the exam
(probably), but there are a variety o f strategies for
keeping these in place. Just know you can pack these
things behind an Amplatzer, or you can use
scaffolding techniques to hook small coils to a large
one
Coils
buzzword
Accurate Deployment’’ = Detachable Coil
Coils
trivia 1
Remember never deploy these with a side-hole + end-hole catheter. You want endhole only for accurate deployment
Coils
trivia 2`
Never pack coils directly into an arterial pseudoaneurysm sac
THIS vs THAT:
Coils vs Micro-Coils
Coils: Deployed via standard 4-7F catheter Micro: Deployed via Micro- Catheter. If you try and deploy them through a standard cath they can ball up inside the thing and clog it.
Amplatzer Vascular Plug (AVP)
overivew
This is a self expanding wire mesh that is made of Nitinol (thermal memory James Bond
shit). You mount this bomb on the end of a delivery device/wire. When deployed it
shrinks in length and expands in width.
Amplatzer Vascular Plug (AVP)
best use
High Flow Situations, when you want to kill a single large vessel. If you are
thinking to yourself - I’m gonna need a bunch of coils to take that beast down the answer is
probably an amplatzer plug.
Particulate Agents
overview
- Temporary: Gelfoam, Autologous Blood Clot
* Permanent: PVA Particles
Particulate Agents
best use
Situations where you want to block
multiple vessels. Classic examples would be fibroids
and malignant tumors.
Particulate Agents
you are doing it wrong/aboiding reflux
An easy way to ask this would simply be “When do
you stop deploying the agent?
Particulate Agents
classic teaching
The classic teaching is to stop embolization when the flow becomes “to and fro.” If you
continue to pile the particulate agent in until you get total occlusion you risk refluxing the agent
into a place you don’t want it to go.
THIS vs THAT:
Gelfoam Powder vs
Gelfoam Pledgets/Sheets
Powder causes occlusion at the capillary level (tissue necrosis) Pledgets/Sheets cause occlusion at the arteriole or larger level (tissue infarct is uncommon)
THIS vs THAT: C o ils vs PVA P a r tic le s
In many cases if you can use coils, you can also use appropriately sized particles.
Size is one way to pick. Coils are good for medium to small arteries. PVA is good for
multiple small arteries or capillaries.
Smaller particles (less than 300 microns) are going to risk tissue necrosis in many cases -
so if you want to preserve the tissue, th a t’s probably the wrong answer.
Another tip for picking between the two is the need for repeat Access. The classic example
is the bronchial artery embolization. These things tend to re-bleed. So you should NEVER
ever use coils (this will block you from re-accessing).
Bronchial artery embolization = Particles (> 325 micrometers).
What do you do after placement o f an occlusion balloon in the setting o f particle embolization ?
Test injection to confirm adequate occlusion.
Liquid agents are grouped into
- Sclerosants: Absolute Alcohol (the one that hurts) and Sodium Dodecyl Sulfate (SDS)
- Non-Sclerosants: Onyx (Ethylene-Vinyl Alcohol Copolymer) , Ethiodol
Sclerosants:
As would be expected, the sclerosant agents work by producing near immediate thrombosis /irreversible endothelial destruction. As a result, non-targeted embolization can be fairly devastating. There are three main strategies for not causing a major fuck up (i.e. burning a hole in the dude’s stomach, infarcting his bowel, e tc …).
(1) Knowing the anatomy really well through careful mapping
(2) Frequent intermittent angiograms during the embolization procedure
(3) Use o f Balloon Occlusion to protect non-target sites.
What do you do prior to deflating the occlusion balloon?
Aggressively aspirate (with a 60 cc syringe) to make sure all the poison is out o f there.
Non-Sclerosants
Onyx:
Typically used for neuro procedure s , h ype rva scula r spine tumor s , shit like that.
It drys slowly (outside in) and allows for a s lower, more controlled delivery
Non-Sclerosants
thiodol:
This is an oil that blocks vessels at the arteriole level ( same as the really
small PVA particles). For some reason, h epa tomas love this stuff, and it will
preferentially flow to the hepa toma. It is also unique in that it is radio-opaque , which
helps decrease non-targeted emboliz a tion and lets you track tumo r size on follow up.
Autologous Blood Clot
Post-Traumatic High-Flow Priapism (or Priapism induced by the female
Brazilian Olympic volleyball team)
Varicocele (Spermatic Vein)
coils
Uterine Fibroid embolization (Bilateral Uterine Artery)
ery) = PVA or microspheres 500-1000
• Generic Trauma
Gel Foam in many cases.
Diffuse Splenic Trauma (Proximal embolization)
Amplatzer plug in the splenic artery proximal to the short gastric arteries. .
Pulmonary AVM
coils
Hemoptysis (Bronchial artery embolization)
PVA Particles (> 325 pm).
Hyper-vascular Spinal Tumor
onyx
Total Renal Embolization
Absolute ethanol
Partial or Selective Renal Embolization
Glue (bucrylate-ethiodized
Segmental Renal Artery Aneurysm
COILS
Main Renal Artery Aneurysm
Covered Stent (or coils after bare metal stent)
Peripartum hemorrhage
Gel Foam
Upper GI Bleed
Endoscopy First (if that fail then in most cases coils)
Lower GI Bleed
Usually Microcoils
LARGE Vessel •
Permanent
coils
amplatz occluder
small Vessel -
Permanent
particles
liquid scleorsants
thrombin
ethiodol
LARGE Vessel -
Temporary
gelfoam pledget/sheet
autologous clot
small Vessel -
Temporary
microspheres
gelfoam powder
Post Embolization Syndrome:
Pain, nausea, vomiting, and low grade fever - is basically an expected finding. You d o n ’t need to order blood cultures - without other factors to make you consider infection. There is a rule o f
3 days - it starts within the first 3 days, and goes away within 3 days o f starting. The vignette is most classic for a large fibroid embolization, but it’s actually common after a solid organ (e.g. liver) - the tumor ju st needs to be big. Some texts suggest prophylactic use o f
anti-pyrexial and antiemetic meds prior to the procedure.
“Threatened Limb
Acute limb ischemia can be secondary to thrombotic or embolic events.
Frequent sites for emboli to lodge are the common femoral bifurcation and the popliteal
trifurcation. You can also get more distal emboli resulting in the so called blue toe syndrome.
As crazy as this may sound to a Radiologist, physical exam is actually used to separate patients
into 3 categories: viable, threatened, or irreversible. This chart (or something similar) is how
most people triage.
Threatened limb
1
Category - Viable Not Threatened
capillary return - intact
muscle paralysis - none
sensory loss - none
arterial doppler - +
venous doppler - +
Threatened limb
2a
Category - Threatened Salvageable
capillary return - intact/slow
muscle paralysis - none
sensory loss - partial
arterial doppler - -
benous doppler - +
Threatened limb
2b
Category - Threatened Salvageable if immediate intervention
capillary return - slow/absent
muscle paralysis - partial
sensory loss - partial
arterial doppler - -
benous doppler - +
Threatened limb
3
Category -Irreversible NOT Salvageable *Amputation
capillary return - absent
muscle paralysis - complete
sensory loss - complete
arterial doppler - -
benous doppler - -
“Critical Limb Isc h em ia ”
h i s is described as
General Idea on Treatment
An important point to
realize is that lysis o f a clot only re-establishes the
baseline (which was likely bad to start with). So
after you do lysis, consider additional therapy
(angioplasty, surgery, stenting, e tc …). If there is
combined inflow and outflow disease, you should
treat the inflow first (they ju st do better).
Surgery vs Thrombolysis
If it has been occluded
for less than 14 days, thrombolysis is superior, if
more than 14 days, (surgery is superior).
ACR Appropriate:
Embolism Above / Below
the Common Femoral
Artery
- Isolated suprainguinal embolism probably should be removed surgically. - Fragmented distal emboli should have endovascular thrombolytic therapy
Ankle - Brachial Index (ABI)
overview
The idea behind the ABI is that you can compare the blood pressure in the upper arm, to that of
the ankle and infer a degree of stenosis in the peripheral arteries based on that ratio. In a normal
person, ratios are usually slightly greater than 1. In patients with occlusive disease, they will be
less than that - with a lower number correlating roughly with the extent o f disease.
Ankle - Brachial Index (ABI)
scores
1.0 Normal No Symptoms
0.75-0.95 Mild Mild Claudication
0.5-0.75 Moderate Claudication
0.3-0.5 Moderate - Severe Severe Claudication
< 0.3 Severe or “Critical” Rest Pain
Ankle - Brachial Index (ABI)
how they do it
You take blood pressures in both arms, and both ankles. You only use one o f
the arm measurements (the higher one). For the actual ratios, opinions vary on this - most
people do it by dividing the higher o f either the dorsalis pedis or posterior tibial systolic pressure
(at the ankle) by the higher o f either the right or left arm systolic pressure
Ankle - Brachial Index (ABI)
false numbers
Arterial calcifications (common in diabetics with calcific medial sclerosis) make compression difficult and can lead to a false elevation o f the ABI. This is when you will see ratios around 1.3 — those are bullshit, means the exam is non-diagnostic.
Ankle - Brachial Index (ABI)
toe pressures
As above, diabetics will have noncompressible vessels - which makes ABIs
worthless. What you can do is look at the toe pressure. The reason this works is because the
digital arteries are not as affected by this disease process. A normal systolic toe pressure is
greater than 50 mm Hg, and the ratio (toe-brachial index) should be more than 0.6. The testable
trivia is that i f the toe pressures are less than 30 mm ulcers are less likely to heal.
Ankle - Brachial Index (ABI)
segmental limb pressures
A modification to the standard ABI involves pressures at the thigh,
calf, and ankle — if there is a pressure drop o f more than 20-30 you can infer that this is the level
of disease. This allows you to sorta sorta sorta guess where the level of disease is.
Spectral Waveform Analysis:
The normal pulsatile wave is the result o f the
pumping action of the left ventricle
transmitted to the aortic root and then to the
foot. As the LV contracts you have a jet of
blood that dynamically expands the aortic
root. As the bolus o f blood travels towards
the feet the vessels will continue to expand
along the path — like a cartoon snake that has
eaten a mouse (or your neighbors cat). The
wave falls as the cardiac cycle enters diastole.
There is a secondary event which is the rebound off
the high resistance tibial vascular tree. This is why
the normal wave has an up-down-up look to it —
“triphasic” they call it. This bounce back or
rebound effect demonstrates normal arterial
compliance. As the vessel hardens you lose this.
With progressive disease there is less and less
compliance to the point where the primary wave
barely even stretches the vessel.
Ulcer Location Trivia
- Medial Ankle = Venous Stasis
- Dorsum o f Foot = Ischemic or Infected ulcer
- Plantar (Sole) Surface o f Foot = Neurotrophic Ulcer
Who are Rutherford and Fontaine
These are “useful” categories and classifications o f
signs and symptoms o f peripheral arterial disease.
PAd false numbers
Arterial calcifications (common in diabetics) make compression difficult and can lead to a false elevation o f the AB1
Post-Operative Bypass Vocabulary
Primary Patency
Uninterrupted patency o f the graft with no procedure done on the graft itself (repair o f distal vessels, or vessels at either anastomosis does not count as loss o f primary patency)
Post-Operative Bypass Vocabulary
Assisted Primary Patency
Patency is never lost, but is maintained by prophylactic
interventions (stricture angioplasty etc..).
Post-Operative Bypass Vocabulary
Secondary Patency
Graft patency is lost, but then restored with intervention
thrombectomy, thrombolysis, etc..
Where to Access
iliac
First Choice - Ipsilateral CFA. If that is down also
(which it often is). I’d pick the contralateral CFA
Where to Access
cfa
Contralateral CFA
Where to Access
sfa
Ipsilateral CFA
Where to Access
fem-fem crossover
First Choice - Direct Stick.
Second choice-inflow CFA
Where to Access
fem-pop graft
Ipsilateral CFA
When would yo u use the contralateral CFA for access
- The Ipsilateral CFA is occluded.
- The patient is very very fat. Even fatter than your normal acute leg patient. These are
the guys/gals who got the milkshake (instead o f the diet coke) with the baconator. As a
point o f gamesmanship, if the question header specifically mentions that the patient is
obese they are likely leading you towards contralateral access.
Watch out for “retrograde” vs “antegrade” access terminology in
the distractors.
The nomenclature for a downward (towards the toe) access is
“ antegrade.” The terminology is based on the directions o f the arterial flow.
Antegrade access
towards the toes
Retrograde access
towards the heart
General Procedural Trivia I Possible “Next Steps”
There are a whole bunch of ways to do this. In the most generic terms, you jam the catheter into the
proximal clot and infuse TPA directly into the mother fucker. Every 6-8 hours you check to see if you
are making progress. People call that “check angiography.”
What i f you can’t cross the clot with a wire?
If they spell that out in the vignette, they are trying to tell
you that this clot is organized and probably won’t clear with thrombolysis.
What i f there is no clearing o f the clot during a “check angiogram ” ?
If they specifically state this,
they are describing “lytic stagnation, ” which for most reasonable people is an indication to stop the
procedure.
The patient develops “confusion ” ?
Neuro symptoms in a patient getting TPA should make you think head bleed. Next step would be non-con CT head.
The patient develops “tachycardia and hypotension ” ?
This in the setting of TPA means the patient is
bleeding out. Next step would be (1) go to the bedside and look at the site. Assuming he/she isn’t
floating in a lake of their own blood (2) CT abdomen/pelvis and probably stopping the TPA
End Point ?
Most people will continue treating till the clot clears. Although continuing past 48 hours is typically bad form.
Varicose Vein Treatment
Just know that “tumescent anesthesia” (lots of diluted subcutaneous
lidocaine) is provided for ablation of veins. Veins arc ablated using an endoluminal heat source. A
contraindication to catheter-based vein ablation is DVT (they need those superficial veins).
DVT
The primary complications of DVT are acute PE and chronic post thrombotic syndrome (PTS).
There are several clinical predictive models to keep everyone who comes in the ER from getting a CTPA -
“Wells Score” is probably the most famous. Recently described is this “Thrombus Density Ratio” as a
superior predictor of PE in patients with known DVT on CTV. The density of thrombus on CTV has been
shown to be higher in patients with both DVT and PE relative to just DVT. Thrombus Density Ratio of
46.5 (thrombus HU / normal vein HU) = probable PE.
Phlegmasia alba (painful white leg) and Phlegmasia cerulea dolens (painful blue leg)
archaic
physical diagnosis terms that are high yield for the exam of the future. Phlegmasia alba = massive DVT,
without ischemia and preserved collateral veins. Phlegmasia cerulea dolens = massive DVT, complete
thrombosis of the deep venous system, including the collateral circulation. These are described as
extreme sequella of May-Thurner - but can occur in any situation where you get a punch of DVT
(pregnancy, malignancy, trauma, clogged IVC filter, etc..)
Post Thrombotic Syndrome (PTS):
This is basically pain and stuff (venous ulcers) after a DVT. Risk
factors include being old (>65), a more proximal DVT, recurrent or persistent DVT, and being fat.
PTS is usually diagnosed between 6 months and 2 years after DVT. VEINES-QQL is the scoring
system used to diagnose and classify severity of PTS. Catheter-directed intrathrombus lysis of
iliofemoral DVT is done to prevent post thrombotic syndrome. This is not needed as much with
femoropopliteal DVT as it will recanalize more frequently and have less severe post thrombotic
syndrome.
An IVC filter is used in the following situations
• Proven PE while on adequate anticoagulation
• Contraindication to anticoagulation with clot in the femoral or iliac veins
• Needing to come o ff anticoagulation - complications. There are a few additional
indications that are less firm (basically, we think he/she might get a DVT and we c an ’t anticoagulate).
IVC filter vocab
- Permanent Filters: Do Not Come Out
- Retrievable Filters: Can Come Out, But Do Not Have To
- Temporary Filter: Come out, and have a component sticking
outside the body to aide in retrieval
IVC filter why not leave them in
Depending on who bought you lunch (gave you a free pen), thrombosis rates vary. In general (for the purpose of multiple choice) about 10% o f the permanent filters thrombose within 5 years.
IVC filter position
The device is usually placed infrarenal with a few exceptions
(see below chart).
Why isn i it always ju s t positioned suprarenal? A supra-renal filter has a theoretic increased
risk o f renal vein thrombosis. There is zero evidence behind this - like most things in
medicine.
IVC filter
Pregnancy
Supra-renal To avoid compression
IVC filter
clot in the renals or gonadals
Supra-renal Get above the clot
IVC filter
duplicated ivcs
Either bilateral iliac, or
supra-renal (above the
bifurcation)
Gotta block them both
IVC filter
circumaortic left renal
Below the lowest renal
Risk o f clot by passing filter
via the renals
megA -Cava
If the IVC is less than 28 mm, then any filter can be placed. If it’s bigger
than that, you might need to place a b ird ’s nest type o f filter which can be used up to 40 mm.
You can also ju st place bilateral iliac filters.
IVF filter
random trivia
- A “Gunther Tulip” has a superior end hook for retrieval
- A “Simon-Nitinol” has a low profile (7F) and can be placed in smaller veins (like an arm vein).
- All filters are MRI compatible
Prior to placing the Filter
You need to do an angiographic run. Where I trained, the classic pimping question for residents on service was to “name the 4 reasons you do an angiogram prior to filter placement!” The only answer that would not result in “additional training” (more weekend
PICC workups) was:
1. Confirm patency o f the IVC
2. Measure the size o f the IVC
3. Confirm that you are dealing with 1 IVC
4. Document the position o f the renal veins
IVC Filter
Malposition
The tip o f the filter should be positioned at the level o f the renal vein. If it’s not, honestly it’s not a big deal
IVC Filter
Migration
The filter can migrate to another part o f the IVC, the heart, or even the
pulmonary outflow tract. If it goes to the heart, you need surgery. If it’s ju st superior, you need to snare it out.
IVC Filter
Thrombosis
Although the incidence o f PE is decreased, the risk o f DVT is increased.
Caval thrombosis is also increased, and you should know that clot in the filter is a
contraindication to removal (you need to lyse it, before you remove it).
IVC Filter
IVC Perforation:
A strut going through the caval wall is common and d oesn’t mean
anything. However, aortic penetration, ureteral perforation, duodenal perforation, or lumbar vessel laceration can occur (rarely) from a strut hanging out o f the cava - this is a bigger problem.
IVC Filter
Device Infection
A relative contraindication to IVC filter placement is bacteremia
Positioning the IVC Filter
Renals on an IVC Gram
There are two ways
to show the renals on an IVC Gram. There is
the nice way where they opacify normally and
it’s obvious, and there is the sneaky way where
you see the “steaming effect ” o f unopacified
blood allowing you to infer the position.
Obviously the sneaky way is more likely to
show up on the exam.
Positioning the IVC Filter
the tip
For standard anatomy, the standard answer for a cone shaped fdter is to put the apex
at the level o f the renals. Some people think the high flow in this location helps any clot that
might get stuck in the filter dissolve.
Positioning the IVC Filter
What i f there is clot in the IVC?
The filter should be positioned above the most cranial
extension o f the clot. As mentioned in my glorious IVC Filter position chart, if the clot extends
beyond the renals you need a suprarenal filter.
Positioning the IVC Filter
What i f you fuck up the deployment (severe tilt, legs won V open, etc…) ?
If it’s retrievable,
you may be able to snare it and restart. If it’s permanent you are kind o f hosed. Some people
will try and stick a second filter above the retarded one.
IVC Filter Removal
The longer these things stay in, the more likely they will thrombose. Prior to removal you
should perform an angiogram o f the IVC. The main reason to do this is to evaluate for clot.
• More than 1 cm3 o f clot = Filter Stays In
• Less than 1 cm-1 o f clot = Filter Comes Out
IVC Filter Removal
You snare the filte r but when you p ull on it you meet resistance ?
In the real world, people
will yank that mother fucker out o f there. The IVC is the Rodney Dangerfield o f vessels - no
respect. For multiple choice? Stop and assume that it can’t be retrieved.
IVC Filter Removal
after removal
Angiogram should also be done after removal o f the filter to make sure you didn’t rip a hole in
the IVC. I f you did rip a hole in it - Next Step - Angioplasty balloon with low pressure
insufflation to to create tamponade. If that doesn’t work, most people would try a covered stent
graft. If you created a wall injury/dissection ? Again - answers will vary, but the classic
answer is systemic anticoagulation
A V F istula
This is a subcutaneous anastomosis between an artery and adjacent native vein
(for example the radial artery to the cephalic vein). All things equal, the preferred access
(over the graft).
A V Graft
This is also a subcutaneous anastomosis between an artery and adjacent native
vein. Except this time the distance between the vessels is bridged with a synthetic tube graft.
Pros o f AV Graft:
- Ready for use in 2 weeks
- Easier to declot (clot is usually confined
to the synthetic graft)
Pros o f AV Fistula:
- Lasts Longer & More Durable
- Much less prone to development o f
venous neointimal hyperplasia at or
downstream from the artery-vein
anastomosis. - Fewer infections
Cons o f AV Graft:
-Less overall longevity
-Promotes hyperplasia o f the venous intima
at or downstream from the graft vein
anastomosis, resulting in stenosis and
eventual obstruction
-More infections (foreign graft material)
Cons o f AV Fistula:
-Needs 3-4 Months to “Mature” (vein to
enlarge enough for dialysis)
