VIR Flashcards
in Subclavian steal syndome, what is the direction of flow seen within the vertebral artery?
”- retrograde vertebral artery flow –> antegrade distal subclavian artery flow
- Subclavian steal syndrome is seen angiographically on the arch aortogram (Fig. 1) and selective left subclavian arteriogram (Fig. 2).
- A dissection flap limits antegrade flow through the proximal subclavian artery resulting in reversal of flow in the left vertebral artery.
- Late-arterial retrograde filling of the left vertebral artery occurred once contrast passed through collateral pathways (not shown).
- Conservative management is often appropriate for asymptomatic patients, while endovascular stenting is preferred over surgical bypass for symptomatic individuals.
- As stated, a subclavian dissection flap is the cause of the steal in this case, not atherosclerotic plaque which more commonly causes subclavian steal syndrome.
- On these early arterial phase images, duplex imaging would reveal reversal of flow within the left vertebral artery, not systolic deceleration. “
Types of Biopsy techniques
“With the coaxial needle technique a single introducer is passed through overlying tissues, and the biopsy needle is then passed through this introducer, thereby minimizing the number of passes.
- Both fine-needle aspiration and the single-needle technique require the needle to pass repeatedly through overlying tissues.
- The Seldinger technique is a vascular access technique.”
what is adrenal vein sampling used for?
“Adrenal vein sampling is used to guide treatment of primary aldosteronism.
- Renin is collected during renal vein, not adrenal vein, sampling to diagnose renovascular hypertension.”
what connective tissue disease is associated with Marfans syndome?
Annuloaortic ectasia (tulip bulb ascending aorta) is present in 75% of patients with Marfan syndrome. The most devastating complication of Marfan syndrome is a type A aortic dissection. Pregnant women with Marfan syndrome are at particular risk of aortic dissection and surveillance imaging should be considered.
Which two muscles are associated with subclavian vein stenosis (thoracic outlet obstruction)?
1) Subclavius muscle and 2) anterior scalene
Pulmonary AVM - indication for surgery?
1) a. Enlarging or b. feeding vessel 3mm,
2) symptomatic (with paradoxical emboli)
What size limit do femoral pseudoaneurysm need to be treated?
2.0 cm is the size limit (above this, unlikely to heal spontaneously and increased risk of distal embolism)
How do you treat Renal artery stenosis? do you stent or not?
“Medical, endovascular or surgery. Medical alone is prefered (no benefit for endovascular treatement)
- WHne you do treat (flash pulmonary edema), need to both plasty and stent.”
How do you treat FMD?
Only angioplasty
What are the two approaches used in portal vein embolization? why is it performed?
”- The patient in Fig. 1 had the embolization performed from a contralateral approach and the embolic agent used was n-butyl cyanoacrylate glue, which appears as a radiopaque cast filling the right portal ducts . The contrast that was injected through the contralateral percutaneous access catheter shows a patent left portal vein , main portal vein , and a small right portal vein filling hepatic segment 6 .
- patient in Fig. 2 underwent PVE via an ipsilateral approach. Particles were initially used as the embolic agent and these were carefully injected into the right segmental portal vein branches. Following embolization with the particles, coils were deployed.
- PVE involves mechanical occlusion of segments of the intrahepatic portal venous system, with the goal of increasing the future remnant liver (FRL) volume in patients in whom partial hepatectomy is planned. Segments of the liver to be resected are embolized distally, typically with glue or particles, resulting in compensatory hypertrophy of the non-embolized hepatic segments. Surgery is performed 4-5 weeks after PVE, which allows time for hypertrophy of the future remnant liver, but limits time for tumor growth within the segment that is to be resected.”
What rate of bleeding can you target for 1)CT, 2) transcatheter embolization and 3)Tagged RBC?
“RBC: 0.1ml/min
angiogram: 1ml/min
CT: need 5ml/min?
angiogram: need 1mg/min
transcatheter embolization of the bleeding source arising from the left colic artery should be possible, as long as the rate of bleeding continues at > 0.5 mL/min.
2) CT: 0.3
(conventional angiography=1; CT is 0.3ml/min; tagged RBC is 0.1ml/min)”
What are the causes of a “failure of a fistula to mature”?
”- Failure of a fistula to mature can be due to multiple issues including 1) stenosis of the fistula outflow vein or of the central veins, 2) arterial anastomotic stenosis and 3) competing collateral outflow veins. Fistula salvage rates of 75% can be achieved following percutaneous intervention.
- images show a brachiocephalic hemodialysis fistula . The only abnormality shown is a competing collateral outflow vein arising from the body of the fistula. This was subsequently embolized by placing an endovascular coil within the collateral vein so as to occlude the competing outflow that was preventing maturation. According to the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (KDOQI)™ guidelines, a mature and functional fistula with have flow rates > 600 mL/min, will be > 0.6 cm in diameter and the depth will be less than 0.6 cm from the skin surface. “
WHich hepatic vein is used in a transjugular liver biopsy?
Right hepatic vein (aim the needle anterior)
what is the normal anatomy of brachial arteries?
”- Arise T5-6
- 2left and 1 right
- need to avoid artery of adamkiewitz (arises T9-12 and on the left)”
Normal flow following TIPS insertion?
”- Flow towards the TIPS (normal velocities of 50-200 cm/s) with
- Main portal vein: pulsetile flow with velocity >30cm.s
- Right and left portal: reversal
- hepatic vein: increased flow
- NOTE: if there is recanalizaed paraumbilical vein, there can be antegrade flow within the Left portal vein (i.e. it does not definitely indcicate TIPS malfunctino but could)”
