IR Flashcards
how is size measured for puncture needles, catheters, dilators, sheaths, wires.
- puncture needle- Gauge. Outer
- catheter/dilator- French. Outer
- sheath- F. inner (Shy and stays in Shell)
- wires: outer diam (inch), length (cm). standard=0.035in and 180cm
T or F: larger the gauge, smaller the wire. Larger the F, larger the catheter.
True
how many inch = 1 mm. How many F = 1 mm
- 0.039 inch
- 3F
how are wires sized? what is the standard wire size for general purposes
- outer diam=inch. Standard= 0.035 inch
- length =cm, standard=180 cm
size of microwires
0.018, 0.014 inches
What size catheter will the standard 0.035 wire fit through?
4F (or bigger)
when are sheaths used? How are they sized?
- cases that require exchange of multiple catheters w/o losing access
- sized via inner lumen. Chosen according to largest catheter they will accommodate
- outer diameter usually 1.5-2F larger than inner lumen, ieL add 2F for outer diam (if you want to know how big the hole in the skin will be)
some conversions… How many F?
- 16G needle has outer diam of 1.65 mm
- 20G needle has outer diam of 0.97 mm
- 5F
- 3F
18G, 19G (seldinger technique) and 21G (micro puncture) needles accept what size guide wire?
- 0.038 in
- 0.035 in
0. 018 in (micropuncture)
when is micro puncture good and bad?
- Good-tough access (Ex: antegrade femoral puncture), lack of experience, anatomically sensitive (internal jugular, dialysis access)
- bad: scarring, obesity, flimsy 0.018 inch guide wire doesn’t give enough support for dilator when upsizing
2 flavors of guidewires
- non-steerable (supportive raises for catheters)
- steerable-tight spots, ex: hydrophilic
“long wire” length and uses
- 260 cm
- upper extremity from groin access, visceral circulation and need to exchange catheters, guide catheter >90cm, through and through situation (body flossing)
minimal guidewire length
-length of catheter + length of guide wire in pt
what’s more likely to cause dissection: short or long floppy tip guidewire
shorter
which guide wire for “tight spots”
hydrophilic
how should stiff guide wires be introduced?
through a catheter
Advantage of J tip guidewires. Significance of number associated with it?
- Don’t dig up plaque and miss branch vessels
- radius of curve (smaller miss small branch vessels, larger miss large branch vessels)
guidewire stiffness: noodle-like, normal, supportive, stiff, hulk smash
- Bentson (floppy tip) (BENdy)
- hydrophilic (standard 0.35 J or straight)
- stiff hydrophilic (heavy duty J or straight)
- flexfinder. Abplatzen stiff or extra stiff. 0.018 platinum plus. V18 shapeable tip
- hulk smash-lunderquist, back up Meier.)
more guide wire stiffness, more…
dissection
use of lunderquist (super stiff) guide wire?
-aortic stent grafting
catheter types
- nonselective (medium and large vessels)
- selective (diff shapes/angles for “selecting” branch vessel)
nonselective catheter types
- pigtail
- straight
selective catheter types
- end hole
- side + end hole
- acute angle (<60˚), curved (60-120˚), obtuse (>120˚)
what happens if you consistently inject through a pigtail
contrast goes out proximal side holes and not the tip –> con’t injection=clot in tip
what should you do before big injection with pigtail Cath?
-small test injection-make sure you’re not in a small branch vessel (pigtails are for medium/large vess)
what if pigtail fails to form as you retract the wire?
push catheter forward while twisting
morphology and utility of straight catheters
- side holes and end hole
- smaller vessels, classic loc=iliac
end hole vs side & end hole selective catheters
- end hold: hand injection. dx angiograms & embolization procedures
- side + end hold- pump injection. SMA angiogram. never use in embolization (material can track out side hole)
utility of angled tip, curved, and recurved selective caths
- angled (<60˚)- aortic arch vessels
- curved (60-120˚)- renal, ?SMA/celiac
- obtuse (>120˚)- celiac/sma/ima
“recurve”
1˚and 2˚ curves
- co-axial system
- guide catheter
- introducer
- microcatheter
- vascular sheath
- 1 catheter inside another catheter/sheath. Ex: catheter inside an arterial sheath
- large catheter guide up to desired vessel then shaped for more conventional distal cath
- introducer=long sheath
- microcath-2-3F for tiny vessels (super selection of peripheral or hepatic branches)
- sheath + hemostatic valve + side arm for flushing
20 for 30
20 cc/second for total of 30 s
-bigger artery, higher rate (try to displace 1/3 of blood per second to get adequate picture)
how are maximum flow rates determined and what is flow rate for 3F, 4F, 5F?
- internal diam, length and #side holes
- 8 mL/s, 16, 24 (~8/F)
Double vs single flush techniques
- double: aspirate –> attach new saline syringe (for neuro stuff) –> flush
- single: aspirate –> tilt 45˚ –> flush w/ SALINE only
what if you accidentally mix blood in with saline on aspiration?
discard syringe and double flush
what if you’re unable to aspirate blood?
1) jammed against side wall-pull back, manipulate cath
2) clot- pull out/clear clot OR blow clot inside (if embolizing that location anyways)
preference for picc line venous access
basilic > brachial > cephalic
preference for central lines/ports
- RIJ > LIJ > REJ > LEJ > Femoral > subclavian
- subclavian=thrombus, PTX
- femoral=infection
dose thrombin injection into pseudoaneurysm
-0.5-1 mL (500-1000u)
when should you not compress a pseudoaneurysm?
above inguinal lig
CI to thrombin injection
- local infection
- rapid enlargement
- distal limb ischemia
- large neck (first for propagation)
- pseudoaneurysm cavity size <1cm
when is surgery indicated for pseudoaneurysm rx
- thrombin fails
- inf
- tissue breakdown
- aneurysm neck too wide
mc arterial access site
femoral
femoral access too high or low
- high (above inguinal lig)-RP bleed
- low: AV fistula
steps when meeting resistance when advancing guide wire during arterial access
1) stop, pull wire out and confirm pulsatile flow
2) will not advance beyond top of needle- flatten needle (negotiate plaque)
3) stops after short distance-fluoro to confirm pw. 4F sheet. hydrophilic wire.
when would you want to do brachial access?
1) fem a out
2) obesity
3) upper limb angioplasty
risks brachial access
1) compartment syndrome
2) stroke if cath passes across GV/arch
3) spasm (small vessel. pox GTN)
* sheat larger than 7F may require surgical cut down
which arm do you use in brachial a access
- left if heading south (abd aorta or LE)
- right if headed north (thoracic aorta or cerebrum)
- equal?-left (non dominant, avoid cerebral vess)
- BP diff >20mmHg systolic sugg stenosis-use other arm
Radial access
1) no bedrest
2) allen test
CI to trans lumbar aortic puncture?
supra celiac aortic aneurysm
approach to trans lumbar aortic puncture?-pt position, spine level?
Prone, left side (avoid IVC)
-high-T12 endplate
mild backache s/p trans lumbar aortic puncture
-psoas hematoma (common)
arterial access anticoagulation pre-procedural requirements
- heparin 2 hrs (PTT < 1.2x 25-35s). can turn on 2 hrs after
- INR 1.5
- coumadin 5-7 d (vit K 25-50 mg IM 4 hrs, FFP/cryo)
- PC >50K
- ASA/plavix 5 d
when do pseudoanuerysms spon’t resolve and resp well to intervention?
<2cm
long narrow neck, small defect
ideal degree of balloon dilation
- 10-20% over normal a diameter
- take out stenosis + stretch a slightly
anticoagulation s/p angioplasty
-1-3 mo anti-platelets (AsA, clopidogrel)
general indications for angioplasty
- 50% stenosis + syxs
- a gradient > 10
- v gradient > 5
where do you not stent
- across joint
- site of possible surgical bypass
exception to angio + stent
FMD
stent types
1) balloon-precise deployment, ex: renal ostium
2) self-expandable- areas that get compressed (ie: superficial loc, ex: cervical carotid or SFA)
closed vs open cell stents
- closed-every segment connected by link. More radial force, less flexible, greater plaque coverage
- open= some stent segments deliberately abscenct-flexible/conforms to tortuous vess, less radial F)
ninitol
used in self-expanding stents vial thermal memory (soft at room T, more rigid at body T)
drug eluting stents
-retard neointimal HP
rough guessing guide for balloon size selecting-aorta, common iliac, ext iliac, CFA/prox SFA, distal SFA
- aorta: 10-15mm
- CI: 8 mm
- EI: 7 mm
- CFA, prox SFA=6mm
- distal SFA=5mm
- popliteal=4mm
stent size selection
- 1-2 cm longer than stenosis
- 1-2mm wider than unstenosed vess
next step: >30% residual stenosis
- pressure gradiant-if normal, stop
- if abN-elastic recoil–> stent
next step: waist won’t go away w/ balloon inflation
switch balloon to higher P or cutting
next step: distal embo
- angiographic run –> limb perfused? no intervention.
- not perfused? IL access and retrieve clot
next step: extravasation in setting of balloon angioplasty
-reinflate balloon
EVAR
endovascular abdominal aortic aneurysm repair
-includes iliacs
TEVAR
thoracic endovascular aortic aneurysm repair
anatomy criteria for EVAR
-proximal landing zone must be 10 mm long, non aneurysmal, <60˚ tortuosity
endograft vs open repair
- endo repair: 30 d mortality less
- aneurysm related mortality equal
- graft complications/re-intervention-higher w/ Endo
requirements of iliac vessels in setting of endograft device deployment
- iliac vessels have angulation >90˚ (esp in heavily calcified)
- iliac a diameter < 7mm -may need to cut down and place temporary conduit
absolute CI to infrarenal EVAR
- landing site won’t allow for aneurysm exclusion
- covering a critical a (IMA in setting of SMA + celiac occlusion, accessory renal feeding a horseshoe, dominant lumbar arteries feeding the cord)
describing aneurysms near renal
- para-renal-umbrella term near renals
- juxta renal- short neck (<1 cm) or encroaches on renal
- suprarenal- involves renal and ext into mesenterics
- crawford type 4 thoracoabdominal aortic aneurysm-ext from 12th intercostal space to iliac bifurcation w/ involvement of orgs of renal, SMA, and Celiac
crawford type 4 thoracoabdominal aortic aneurysm
ext from 12th intercostal space to iliac bifurcation w/ involvement of orgs of renal, SMA, and Celiac
when does paraplegia occ in setting of EVAR. Next step?
- artery of adamkiewicz territory covered (T9-12)
- next step=CSF drainage
vertebral level take off: celiac, sma, renal, ima
- T12
- L1
- L2
- L3
most common type of endoleak
type 2
which endoleaks must be treated?
- High flow, emergently: type I and III
- observe type 2, treat if enlarging
- type IV resolve ~48 hrs
embolizations options in setting of big vessel
permanent: coils (lung AVM)
temporary: gel foam pledget (trauma)
embolization options in setting of small vessel
- permanently kill: liquid (RCC ablation)
- permanently wound: particles (fibroid embo)
- temporary: microsphere (chemo)
embo option to slow flow but not occlude
- large proximal embolic (coils, plugs, large particles 500-100µm)
- ex: GI bleed
embo option to totally infarct
- distal embolic small particle, <250µm
- ex: tumor ablation
coils
permanently occlude large vessels
- diff sizes and shapes
- push via coaxial system OR chased via saline bolus if exact precision not needed
- complex: pack behind amplatzer or use as scaffolding to hook small coils to a large one
coil vs microcoil
- deployed via standard 4-7F cath
- micr: deployed via microcath. I f you try to to deploy standard cath and ball up inside thing and clog it
which coil to use in setting of accurate deployment
End hole detachable coil
device from which a coil should never be deployed
-side hole end hole.
amplatzer vascular plug (AVP)
- self expanding wire mesh made of nitinol mounted at end of delivery device/wire.
- when deployed: shrinks in length, widens
- use: high flow station when killing a single large vessel. Going to need a lot of coils to take that beast down.
particulate agents
- temporary- gelfoam, autologous blood clot
- permanent-PVA particles
- use: want to block mult vess, ex: fibroids
gel foam powder vs gel foam pledgets/sheets
powder- causes occlusion at capillary level (tissue necrosis)
-pledget/sheet-occlusion at arteriole or larger level (infarct less common)
when do you stop deploying deploying particulate agent
“to and fro”- if you get total occlusion, you risk refluxing
coils vs PVA particles
- size: coils for medium to small arteries. PVA for small a’s to caps
- need for repeat
next step: what do you do after placement of occlusion balloon in setting of particle embolization?
test injection to confirm adequate occlusion
liquid agents
- sclerosants-absolute EtOH (it hurts) and sodium dodecyl sulfate (SDS)
- non-sclerosants- onyx (ethylene-vinyl Alocohol copolymer), ethiodol
how do sclerosis agents work?
near immediate thrombosis/irreversible endothelial destruction
-nontargeted embo=devastating: know anatomy, f angiograms, balloon occlusion
what do you do prior to deflating occlusion balloon in setting of sclerosing agents?
-aggressively aspirate (w/ 60 cc syringe) to make sure all poison is out
onyx
- non sclerosant liquid embo agent used in neuro procedures.
- dries slowly (outside in) allowing for controlled delivery
ethiodol
- non sclerosant liquid embo agent. Oil that blocks vessels at arteriole level (same as small PVA particles)
- hepatomas love it
- radio-opaque- decreases non-target embolization, track tumor size on f/u
post-embolization syndrome
- pain/n/vom/low grade fever
- rule of 3
- classic for large fibroid
- ppx w/ anti=pyrexial, antiemetic
frequent limb embolic sites
- CF bifurcation
- popliteal trifurcation
triaging limb ischemia based on physical exam
- category 1 (viable)
- category 2a (threatened). Salvageable.
- category 2b-(threatened.) salvageable if immediate intervention
- category 3 (irreversible)
Category 1 limb ischemia
Viable. Not threatened.
- Capillary return in tact.
- No m paralysis or sensory loss.
- a doppler +
- v doppler +.
category 2a limb ischemia
Threatened. Salvageable.
- cap return intact/slow
- M paralysis (-)
- sensory loss-partial
- arterial doppler (-)
- venous doppler (+)
category 2b limb ischemia
Threatened. Salvageable if immediate intervention
- cap return slow/absent
- m paralysis-partial
- sensory loss-partial
- a doppler (-)
- venous doppler (+)
category 3 limb ischemia
Irreversible/not salvageable/amputation
- cap return (-)
- m paralysis (+)
- sensory loss (+)
- arterial doppler (-)
- venous doppler (-)
“critical limb ischemia”
rest pain for 2 wks (or ulceration or gangrene)
treating limb ischemia: inflow vs outflow
inflow first
surgery vs thrombolysis limb ischemia
- occluded <14d-thrombolysis
- occluded > 14d-sx
- isolated suprainguinal embo-sx
- fragmented distal emboli-thrombolysis
choosing values for ABI
- BP both arms & ankles. systolic measurement.
- use higher arm
- use higher dorsals pedis or pst tibial
categorizing ABI severity:
- N. ø syx
- 0.75-0.95-Mild. mild claudication.
- 0.5-0.75-moderate. claudication.
- 0.3-0.5-moderate/severe. severe claudication.
- <0.3-severe/critical. rest pain
toe pressure
- distal toe P in diabetics (these a’s not affected)
- N values: systolic >50mmHg, TBI > 0.6
at what toe pressure is ulcer less likely to heal?
<30 mmHg
segmental limb P
- modification to standard ABI
- pressures at thigh, calf, ankle
- drop of 20-30 mmHg-infer level
what makes limb spectral waveform triphasic?
high resistance tibial vascular tree-rebound effect via normal arterial compliance.
-lost in setting of PAD
ulcer location: venous stasis, ischemic/infected ulcer, neurotrophic ulcer
- medial ankle
- dorsum of foot
- plantar (sole)
Rutherford and fontaine?
categories and classification of sgx and syx PAD
post-op bypass vocab: primary patency
uninterrupted latency of graft with no procedure done on the graft itself
-repair of distal vessels or vessels at either anastomosis does not count as loss of primary latency
post-op bypass vocab: assisted primary patency
Patency never lost but maintained by ppx (stricture angioplasty, etc)
post-op bypass vocab: secondary patency
graft latency lost, then restored with intervention (thrombectomy, thrombolysis, etc)
best route of access for mx threatened limb: iliac
- IL CFA (1st choice)
- CL CFA
best route of access for mx threatened limb: CFA
CL CFA
best route of access for mx threatened limb: SFA
IL CFA
best route of access for mx threatened limb: fem-pop graft
IL CFA
fem-fem cross over
- direct stick (1st choice)
- inflow CFA
best route of access for mx treated limb
shortest, most direct
When would you use CL CFA for treating a lesion in setting of threatened leg
1) The IL CFA is occluded
- pt fat
antegrade vs retrograde access
- arterial flow
- antegrade=towards toes
- retrograde=towards heart
check angiography
-infusing TPA directly into clot. Check every 6-8 hrs for progress
what if you can’t cross the clot with a wire
it’s organized and probably won’t clear with thrombolysis
lytic stagnation
- clot not clearing during check angiogram
- stop the procedure
what if pt develop confusion in setting of thrombolysis
non-con ct
what if the pt level hypoTN and tachycardia in setting of TPA
- bedside eval
- ct abd/pelvis
- stop tpa
what’s the end point for tpa?
-typically stop after 48 hrs (even if not totally cleared)
varicose v treatment-“tumescent anesthesia”
- lots of diluted subcutaneous lidocaine provided
- ablated via endoluminal heat source
CI to varicose v rx?
-DVT
complications dVT
- acute PE
- chronic post thrombotic syndrome
predictive models for CTPA
- wells
- thrombus density ratio
Thrombus density ratio
DVT HU : normal v HU > 46.5 ==> likely a PE
phlegmasia alba
painful white leg seen in setting of massive DVT
- ø ischemia
- preserved collateral v’s
phlegmasia cerulea dolens
painful blue leg
-complete thrombosis of deep venous system, including collaterals
when are plegmasia alba and cerulean dolens terminology used?
- extreme sequela of May-Thurner
- any sitch w/ massive DVT, ie: pregnancy, trauma, malignancy, clogged IVC filter
post thrombotic syndrome (PTS)
sequelae of DVT.
- pain, ulcers
- RFs: >65 yo, prox DVT, recurr/persistent DVT, fat
- 6 mo-2yrs s/p DVT
what is done to prevent pst thrombotic syndrome
- catheter-directed intrathrombus lysis of iliofemoral DVT
- (not needed for femoropopliteal)
permanent vs retrievable vs temporary filters
- permanent-do not come out (10% thrombus w/I 5 yrs)
- retrievable-can but don’t have to.
- temporary-will come out. Component sticks outside body to retrieve
when are suprarenal IVCs placed?
- pregnancy-avoid compression
- clot in renal or gonads-get above clot
- duplicated IVCs
- circumaortic left renal v
risk of suprarenal ivc filter
renal v thrombosis (not at all proven)
ivc filter used based on IVC size
- IVC < 28 mm-any
- bird’s nest if bigger, up to 40mm
gunther tulip & Simon nitinol ivc filters
GT: superior end hook for retrieval
SN: low profile (7F), placed in smaller v’s (arm)
are IVC filters MRI compatible?
yes
check list bf placing filter
1) confirm IVC patency
2) measure IVC size
3) confirm 1 IVC
4) document position of renal v’s
complications/risks of ivc filters
- malposition-tip at renal v
- migration-heart requires sx. otherwise snare
- thrombosis-caval thrombosis=CI to removal; requires lysis
- ivc perforation-problem if aortic, ureteral, duodenal, lumbar vessel
- filter infection-bacteremia=relative CI
steaming effect
unspecified blood entering renal v’s let’s you infer correct position of IVC filter
IVC removal-first step
angiogram-evaluate for clot
- > 1 cm3=stays in
- <1 cm3= comes out
next step: meet resistance when removing IVC filter
stop
what should be done after IV filter removal?
angiogram-confirm no rupture
- if rupture: angioplasty–> covered stent
- if wall injury/dissection–> anticoag
MC dialysis AV fistula
radial a – cephalic v
pros of AV graft
- use w/I 2 wks
- easier to declot (thrombus usually confined to graft)
comps of AV graft
- less longevity (only 50% latency at 2 yrs). Require higher flow rates to remain patent
- HP venous intima or dostreat from graft v anastomosis–> stenosis, obstr
- inf+ (foreign)
- 6-10x (+) risk inf, thrombus
pros of AV fistula
-last longer, more durable
con’s of AV fistula
-3-4 mo maturation
when should you obtain diagnostic fistulogram in setting of AV graft/fistula slow flow?
- graft: <600 cc/min
- fistula: <500 cc/min
why do AV grafts/fistulas fail?
hyperplasia –> stenosis/occ/thrombus
*all must die
why’s a normal physical exam for AV graft
- easily compressible pulse
- low pitched bruit (systole & diastole)
- thrill-palpable w/ compression only at arterial anastomosis
high pitched bruit
stenosis
swollen arm, chest, cw collaterals in setting of av graft/fistula
central venous obstruction
where is the problem usually in av grafts?
venous outflow
if you fix a stenotic av fistula, they’re good to go, right?
reoccur 75%
systolic thrill in av fistula
stenotic.
should be con’t at anastomosis
2nd thrill in av fistula
another stenosis. should only be 1
steal syndrome in setting of av fistula
- blood preferentially going to fistula due to stenosis in native artery distal to fistula –> cold painful fingers.
- rx= sx. distal revascularization and interval ligation of extremity (DRIL), or flow reduction banding.
CI to accessing/treating av fistulas/grafts
- infection=absolute
- <3- d
- long segm 7 cm stenosis
what dir do you access av graft
- toward venous anastomosis, ie: antegrade
* assuming v is the problem, which it usually is
how do you look at arterial anastomosis
obstruct venous outflow –> contrast reflux into artery
what are moves for angioplasty of a narrow spot?
- heparin 3000-5000u
- exchange cath for 5 or 6F sheath over standard 0.035
- dilate w/ 6-8 mm balloon
when do you place stent in setting of av fistula/graft stenosis
1) bad elastic recoil
2) recurrent stenosis w/I 3 mo angioplasty
role of nitro in av fistula/graft stenosis
differentiate spasm vs stenosis
what’s considered a success rx for av fistula/graft stenosis
1) improved syxs
2) <30% residual stenosis