Brant and Helms Ch' 25 Interventional Radiology Hoon Kang

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Brant and Helms Ch. 25Interventional
RadiologyHoon Kang
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Basic Interventional Radiology

• Being Interventional Resident or Taking
  Interventional Call
• Assessment of patient/indication, etc
• Common Interventional Procedures

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Top Five Myths of IR Call/Rotation

• 1. Given 6, IR residents do not need to know the
  pager numbers of techs, nurses, or even the
  attending on call
• 2. The Best IR Resident refuses all the studies.
• 3. If you accept to do a procedure, it can be
  done in the morning
• 4. If the operator doesnt have your name, then
  you are not on call.
• 5. If order was put in without consulting you,
  then it was never ordered.

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Assessment/Screening patient for procedures

• Name, MR, location, attending and resident name
  and pager, procedure indicated, consents.
• Relevant labs, especially, coagulation, meds
• Relevant condition, Vents, Needs for
  Anesthesiology.

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Assessment of Patient Indication

• Patients Condition
• Is the patient stable for the Intervention?
• Is the patient consentable?
• Is the patient properly prepped? NPO?
• Indication?
• Why now? Is it emergent?
• Are there better alternatives?
• Contraindication?
• Prior Surgeries?
• Coagulopathies?
• Long term plan?

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Assessment of Patient Coagulation and Labs

• PT/INR lt 16 sec, INR lt 1.5
• PTT lt 40 sec
• Platelet gt 50,000
• Cre lt 1.5
• HH
• Current Anticoagulation, Pre-medication, ABX
  needs.

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Assessment of Patient Physical Examination

• Head/Neck Exam for conscious sedation/intubation
  needs.
• Vitals. Mental Status. Positioning needs
• Pulses groin, ant/post tibial, brachial, radial
  etc.

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Nonvascular Intervention

• Percutaneous Biopsy
• Abscess and Fluid Drainage
• GU Intervention (Nephrostomy)
• Biliary Intervention

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Percutaneous Biopsy

• CT, US, or Fluoroscopy is used to guide the
  biopsy needles.
• Fine needle Aspiration (FNA) uses 20 to 23 gauge
  for cytologic analysis or fluid sampling
• Core biopsy needles (uses the gun) are 14 to 20
  gauge cutting needles for histologic analysis.

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Percutaneous Biopsy

• Safest route is usually the shortest
• Except Liver
• To avoid crossing a fissure in the lung
• Most common complications included bleeding, and
  pneumothorax (monitor with follow up CXR).

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Abscess and Fluid Drainage

• Initial placement with needle (with sheath) is
  performed under guidance.
• After taking some amount of fluid out, wire may
  be introduced and exchanged with a catheter.
• Drainage catheters range from 6 F to 20 F.
• Viscous fluid require larger catheters (gt10 F)

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Piriformis. Sciatic Nerve
Sacrospinous ligament.
Transgluteal Percutaneous Abscess Drainage Stay
medial and inferior to avoid neuro-vascular
structures
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Abscess and Fluid Drainage

• Once Catheter is in place, it is secured and
  attached to gravity drain or low suction.
• The catheter should be irrigated at least once a
  day.
• The catheter may be removed with output less than
  10-20 cc per 24 hour period.

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Genitourinary Intervention

• Percutaneous Nephrostomy
• Ureteral Stents (Anterograde)
• Whitaker Test
• Abx Unasyn 3 G IV

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Percutaneous Nephrostomy

• Relief of mechanically obstructed renal
  collecting systems.
• Can be performed in transplanted kidney
• Provide urinary diversion for urinary leaks and
  fistulas until repair.

Malecot tube and Pigtail Catheter
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Nephrostomy Procedure

• Patient is in prone or prone-oblique.
• Skin entry is at the posterior flank below the
  12th rib.
• Needle entry should be at the Posterior Calyx
  (Brodel line) of the middle or lower pole.

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Nephrostomy Procedure

• Once the stylet is removed, and urine is returned
  if an obstruction is present.
• After confirming the location with contrast,
  subsequently wire, dilator, then the pigtail is
  exchanged

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Nephrostomy

• Most common complications are hematuria, bleeding
  (subcapsular hematoma, vascular injury) and
  infection

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Ureteral Stents

• Ureteral stent placement is often possible from
  an antegrade approach, at time of nephrostomy
  placement.
• Obstructed ureter is crossed with the use of
  simple curved angiographic catheters and
  hydrophilic guide wires.
• Nephrostomy is removed later, under fluoro

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Ureteral Stents
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Whitaker Test

• To determine if the dilated collecting system is
  due to obstruction in patient producing urine,
  when nuclear study is equivocal.
• A dilute saline-contrast mixture is perfused into
  the renal pelvis at 10 cc/min and pressure
  gradient is simultaneously measured at the renal
  pelvis and the bladder. Normal is lt 15 cm of
  water.

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Biliary Intervention

• Transhepatic cholangiography
• Percutaneous Biliary Drainage/ Biliary Stents
• Cholecystostomy
• Abx Unasyn 3 G IV ( or Amp/GentFlagyl)

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Transhepatic Cholangiography

• Cholangiogram is obtained when contrast is
  injected into the biliary tree transhepatically
  using a noncutting needle.
• If ERCP is not attainable or complicated by prior
  surgery.
• Biliary drainage/stents may be placed at the same
  time
• Risk bacteremia/sepsis, hemobilia, vascular
  injury, and peritonitis

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Transhepatic cholangiography
Sclerosing cholangitis
Klatskins Tumor
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Percutaneous Biliary Drainage

• Access obtained like cholangiography but drainage
  catheter is placed, possibly across the stenotic
  lesion
• Types External, Internal, Internal-external
• Stents can be either plastic or metallic
  (permanent, larger diameter).

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Dx Carolis Disease
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Cholecystogram.
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Cholecystostomy

• Treatment for acute cholecystitis in patients who
  are not operative candidates.
• US/CT/Fluoro guidance via Transhepatic approach
  through bare area in the gallbladder fossa
  (minimizes leakage)
• Catheter must be left in place 2-3 weeks.

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Basic Vascular Interventions

• Angioplasty (PTA)
• Vascular Stenting
• Thromblysis
• Embolization

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Angioplasty

• Percutaneous Transluminal Angioplasty (PTA)
• Procedure in which stenosed blood vessel is
  dilated by inflating a catheter-mounted balloon.
• Stenotic artery is successively dilated using
  incrementally larger balloon

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Angioplasty Mechanism

• 1. Dilation of the balloon stretches the vessel
  wall, fracturing the plauqe, intima and
  irreversibly disrupting the media (to prevent
  recoil).
• 2. Subsequent healing and remodeling results in
  a larger diameter vessel lumen.

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Angioplasty Indication

• Most vascular system in which hemodynamically
  significant stenoses result in clincally
  significant symptoms.
• Chronic Ischemia of Lower ExtremitiesClaudication
  , Nonhealing ulcers, gangrene.
• Upper extremitiesVertebral steal, claudication
• Renal Artery StenosisFMD, transplant, etc.
• Dialysis Graft, etc.

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Angioplasty Complication

• Intimal dissection
• Thrombosis
• Distal Embolization
• Vessel Rupture (rare)
• Greater in patients on chronic steroids or
  certain collegen vascular Dz (Ehler-Danlos type
  IV).

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Angioplasty Results

• Aortoilliac 1 year 90 patency, 5 year 70
• Femoropopliteal 1 year 60, 5 year 40
• Renal Artery Fibromuscular dysplasia (90
  success) Atherosclerotic disease (70)
• Shorter lesion (lt 3 cm) have better outcome than
  longer lesions (gt7 cm).
• Concentric lesions are better than eccentric.

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Dx? Fibromuscular Dysplasia
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Vascular Stenting

• Consists of struts, once embedded into the vessel
  wall, promotes rapid re-endothelialization and
  long term patency.
• Palmaz stent Rigit slotted tube with little
  elastic recoil
• Wallstent Self expandible, flexible wire mesh

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Vascular Stents

• Contraindicated in
• PTA induced vascular rupture
• Infection and bacteremia
• Results variable, depending on location
• Stent-grafts (nonporous) in the future may be
  useful in vascular rupture.

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Dx? SVC syndrome
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SVC syndrome
A Palmaz P308 stent mounted on a 12-mm balloon
was deployed in the superior vena cava after it
was predilated to 8 mm. The stent was
subsequently dilated to 14 mm
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Thrombolysis

• Process of clot dissolution, using a thrombolytic
  agents, via a catheter (need ICU monitoring
  during tx)
• Useful in peripheral vascular thromboelbolism
  causing occlusion and ischemia.
• In severely ischemic limbs with motor and sensory
  loss, surgery is indicated.

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Thrombolysis Contraindication

• Active bleeding
• Recent GI bleeding
• Intracranial tumor
• Recent Stroke or Neurosurgery
• Irreversible extremity ischemia

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Thrombolysis Mechanism

• Plasmin, derived from plasminogen, disrupts
  fibrin cross links to achieve clot dissolution.
• Urokinase (half life 17 min), and t-PA (5 min)
  activates plasminogen to form plasmin
• Streptokinase is an indirect plasminogen
  activator (allergic rxn more common)

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Embolization

• Used in variety of clinical setting of
  uncontrolled bleeding when medical and surgical
  therapy are unsuccessful.
• Permanent Coils, alcohol foam, absolute
  alcohol.
• Temporary Gelfoams

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Embolization for GI bleed
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Embolization Key points

• Embolization of end arteries will lead to tissue
  necrosis
• Do not overembolize as controlling the flow
  dynamic may be enough.
• Small particles increase the risk for tissue
  necrosis.

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Special Vascular Procedures

• Inferior Vena Cava Filters
• Dialysis Grafts
• Venous Acesss
• TIPS

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IVC Filter 4 main types

• Greenfield
• LGM-Vena Tech Self-centering
• Simon nitinol Small, flexible, may be placed
  from arm vein.
• Birds Nest May be used in larger IVC (but lt40
  mm)

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Trap-Ease, Greenfield, Simon Nitinol, Birds
nest
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IVC Filters Indication

• DVT or PE in patients who have contraindications
  to anticoagulation
• Recurrent PE despite adequate anticoagulation
• Large free floating clots, etc
• Not recommended for young patients with long life
  expectancy.

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IVC Filters Procedure

• 1. May be inserted from either femoral or
  internal jugular vein (right preferred)
• 2. IVC-gram is performed to assess presence of
  clot, IVC anatomy and size.
• 3. Best placed in the IVC immediately below the
  most inferior renal vein origin.

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Double IVC
Circumaortic renal vein?
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IVC Filter Complications

• Filter migration
• Malpositioning/tilting
• Caval perforation
• IVC thrombosis.

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Dialysis Grafts

• Have finite life span with average patency of 20
  months.
• Periodic interventional procedures may extend the
  patency.

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Dialysis Grafts

• Arteriovenous Bridge Grafts (more common) are
  made with synthetic PTFE in the forearm.
• Brescia-Cimino Fistulas are native AV fistula
  formed by anastomosis (radial artery and cephalic
  vein at the wrist)

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Dialysis Graft

• Most common failure is the stenosis at the venous
  anastomosis site.
• Other failures may be due to more proximal venous
  stenosis (arm or near SVC), arterial plug, or
  thrombosis.
• Tx Angioplasty and thrombolysis
• (75-100 success rate

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Venous Access

• Tunneled Central Catherers
• Groshong, Broviac, and Hickman, etc
• Dialysis catheters
• High flow double lumen
• PICC (peripherally inserted central catheters).
• Implantable Ports

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Venous Access

• All patients receive ANCEF 1 G IV (or Vanco)
• Acute Complications
• Air embolism, pneumothorax, arterial injury,
  brachial nerve injury, and cardiac arrhythmias.
• Late Complications
• Infection, thrombosis, fracture and migration or
  catheter fragment.

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An Amplatz snare has been used to strip off the
fibrin sheath. Note the free flow of contrast
material from the catheter tip
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Transjugular Intrahepatic Portosystemic Shunts
(TIPS)

• Indication
• Portal hypertension complicated by uncontrolled
  acute variceal bleeding.
• Recurrent variceal bleeding.
• Refractory ascites

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TIPS Contraindication

• Severe right-sided heart failure
• Polycystic liver disease
• Severe liver failure
• Relative Contraindication
• Portal vein thrombosis
• Vascular liver masses
• Poorly controlled hepatic encephalopathy
• Systemic infection

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TIPS Procedure

• After initial access via right IJ, TIP needle
  creates a connection between the proximal right
  hepatic vein and proximal right portal vein.
• Balloon angioplasty and Wallstent is used to
  maintain the parenchymal tract.

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CO2 contrast was used to visualize the portal vein
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Varices were embolized during TIPS
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TIPS

• Target portosystemic pressure gradient is 12 mm
  or less.
• There is resulting hepatofugal flow in the left
  portal vein.
• Final portovenogram is performed for confirmation
• Varices from the coronary veins may be embolized
  once TIPS is created.

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TIPS Results

• High immediate technical success (95-100)
• 75 6-month and 50 1 year patency (improves to
  85 1 year with follow up angioplasty)
• Common complication is encephalopathy.

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The End

• Brant and Helms, Chapter 25
• www.emedicine.com Especially section on
  vascular interventional radiology
• Numerous Journals that I wont mention here.