Vascular Access Devices and Catheters

• Main goal of puncture/access needles is to reach the vessel's lumen, whether arterial or venous
• Guidewires must fit inside the needle's inner diameter
• Once the needle comes out, the catheter must fit over the guidewire
• Needle sets often come in 3-part packages

Access Needle Components

• Cannula: Blunt-ended metal tube
• Lumen: Hole through the needle
• Obturator/Stylet: Thin metal rod inserted to block the lumen, prevents coring, and is removed for guidewire entry
• Coring: Cutting of a tissue plug as the needle passes through, prevented by the obturator
• Bevel: Angled surface formed by grinding the needle point
• Hub: Attaches to the cannula for syringe or device connection
• Luer Lock: Locks the needle to a syringe using a threaded hub

Needle Types & Applications

• Seldinger Needle: Two-part needle with a thin-walled outer cannula and inner stylet that can be beveled, diamond-shaped, or pointed and is used for arterial or venous puncture and available in 16-, 18-, and 20-gauge sizes
• Two-Part Needle System: Includes an outer beveled or non-beveled cannula and a removable sharp three-sided stylet and is commonly 18 or 21 gauge and 10, 15, or 20 cm in length and is used for percutaneous transhepatic cholangiography & splenoportography procedures, biopsies, and fine needle aspiration procedures but is not steerable due to the 3-sided tip
• Two-Part High-Gauge Needle: A beveled edge for steering, usually 20 or 22 gauge and 15 or 20 cm long and is used for biliary and renal access and also used for percutaneous transhepatic cholangiography & splenoportography procedures, biopsies, and fine needle aspiration procedures
• Three-Part Needle: Includes a beveled cannula, stylet, and fitted radiopaque Teflon outer sheath and is available in 16, 18, & 20 gauge sizes and is used for femoral, brachial, and axillary artery puncture, femoral vein, & for vascular grafts
• Three-Part Needle: A beveled outer cannula, a hollow, beveled stylet, and a blunt obturator and used for arterial and venous puncture and available in an 18-gauge size

Needle Sizes

• Needles are measured by the Stubbs needle gauge
• Larger Stubbs number means a smaller outside needle diameter
• Needle size ranges from largest (7g) to smallest (33g)

Guidewires

• Constructed from flexible stainless-steel coil
• Threaded through the needle's lumen
• Length should be a minimum of 10 cm longer than the catheter, often twice the catheter length
• Spring guide holders prevent contamination/bending
• Handling requires care to avoid contamination

Guidewire Properties

• Diameter, stiffness, and hydrophilic or non-hydrophilic composition are main properties
  • Hydrophilic coatings: Reduce friction for easier movement in tortuous vessels, slippery when wet
  • Non-hydrophilic wires: Easier to grip, less sticky, but may offer more resistance in narrow areas
• Pushability, steerability, torque, and opacity also characterize guidewires

Types of Guidewires

• Introduction Guidewire: Coated in Teflon, flexible straight or curved "J" tip, usually shorter ("short J guidewire")
• Exchange Guidewire: Very long with a flexible "J" tip, used to replace/exchange catheters during procedures
• Floppy Tip: Used to pass atherosclerotic narrowed lumens

Dilators

• May be required to dilate tissue and vessel walls
• Slipped over the guidewire to enlarge the opening
• Multiple dilators may be used in a procedure, ranging from smaller to larger sizes
• Stiffer and larger in inner diameter to fit over the guidewire
• Made of the same material as catheters but are stiffer

Introducer Vascular Sheaths

• Catheter type that maintains vessel access
• Includes a valve to prevent blood loss
• Allows exchange of instruments without losing access like guidewires, catheters, instruments
• Causes less trauma at the entry site
• Common length is 15 cm, longer sheaths (25 cm) are useful for iliofemoral artery tortuosity or atherosclerosis
• Peel away sheaths keep the catheter in position post-procedure, like drainage catheters or central lines

Catheters

• Long, narrow, disposable tubes for injecting contrast media and other substances into a vessel's lumen
• Two main categories: non-selective and selective

Non-Selective (Flush) Catheters

• Typically have many distal side holes with straight or pigtail shapes

Selective Catheters

• End-holed or side-holed, come in varied shapes and sizes for the varied branching of vessels

Super Selective Catheters

• End-holed or side-holed, fits the varied branching of smaller vessels
• Can be highly specialized for specific interventional procedures
• May have a hydrophilic coating for smoother advancement
• Non-vascular catheters share many characteristics but are typically larger in Fr. size (8-16 French) & stiffer for drainage function

Catheter Shapes

• Distal tip configuration describes the curve on the leading edge

Non-Selective Catheters

• Pigtail with side holes - 5 French at 20-25mL/s
• Straight with side holes - 5 French at 20-25mL/s

Selective Catheters

• Cobra (end hole or with side holes): Used for visceral and peripheral selective angiography, 3 curve sizes are available (C2 most popular)
• Vertebral (end hole only): Angled tip ideal for catheterization of forward-facing vessels, such as branches off the aortic arch
• Berenstein: Similar to vertebral, with a tip angle closer to 90 degrees

Catheters (cont.)

• Simmons “Sidewinder” or SIMS (end hole): Used for visceral selective angiography, 3 sizes available (1, 2 and 3) with progressively widening curves & longer limbs
• Renal Double Curve - RDC (end hole): For renal selective angiography
• Headhunter (end hole or with side holes): Primarily used to catheterize neck and head vessels, catheter springs into vessels

Parietal vs. Visceral

• Visceral: Structures related to organs
• Parietal: Structures related to the wall of the body cavity

Catheter Label Information

• Typically lists catheter material, French size and length, shape, maximum acceptable guidewire diameter, maximum acceptable flow rate & pressure, number of side holes or end holes, lot number, packaging date, and expiry date

Catheter Characteristics

• Memory: Ability to regain original shape after guidewire passage
• Torque: Response to twisting and turning, larger French size catheters have better torque control
• Friction co-efficiency: Coated in Teflon to reduce friction from vessel walls
• Thrombogenicity: Immersed with heparin to reduce thrombosis formation
• Shape: Straight or round tips
• Radiopaque polyethylene: Allows visualization during insertion process
• Designed in a variety of shapes and curves to select branch vessels that originate at different angles
• Round tip reduces the risk of damaging the vessel’s inner wall
• Side Holes: Tiny holes along the end of the catheter that reduces whiplash effect from fast injection can apply a greater volume and rate of contrast and resistance to infection and clotting

Catheter Sizes

• Measured in inches, millimeters, or French number
  • French scale: 1 French = ⅓ mm diameter
• Smaller French number, smaller the outside diameter
  • 1F = 0.33 mm diameter
  • 3F = 1mm outer diameter
  • 6F = 2mm outer diameter
• Package label shows size/shape/material/side holes, end hole, length, and suggested guidewire size
• Lengths commonly vary from 60 - 100 cm

Catheters with Specific Characteristics

• Equipped with tools/attachments like measuring instruments, angioplasty balloons, baskets/forceps for foreign body retrievals or biopsies, fiber optics, hemorrhage control devices, selective drug distribution, Bx and US imaging capabilities

Interventional Catheters

• Percutaneous Transluminal Angioplasty (PTA) catheters have an outer segment (balloon) at its tip that can be inflated to a pre-determined diameter
• Basket retrieval catheter

The Angiographic Tray

• Includes: Myelography Tray, Arthrography Tray, Seldinger Technique Tray and a Cut down tray

Tray Contents

Prep Group

• Sterile drapes, prep applicators, absorbent towels, 2x2 sponges, removable antiseptic basin, Sterile IR cover

Anesthetic Group

• 5ml Xylocaine
• 5 ml syringe
• 25g - 21g -18g needles

CM Injection Group

• 10ml - 20ml syringe
• Extension tubing
• Hemostats
• Scalpel
• Connectors
• Stopcock

Embolizing Agents

• A material or medication that creates a blockage in a blood vessel which is used to halt blood flow to a specific area and is delivered via catheters
• The interventionalist selects the best agent based on vessel type/size and the temporary or permanent need for the blocking of the blood vessels

Thrombolytic Agents

• Medications used to dissolve blood clots in the body, administered through an IV or catheter
• Used to treat heart attacks, pulmonary embolisms, and strokes
• Help dissolve blood clots related to DVT and PAD

Embolizing Agents (Types)

Mental Coils

• Gianturco
• Detachable
• Platinum coated

Particulate Agents (Permanent)

• Polyvinyl alcohol (100–1200 µ)
• Embosphere (100–1200 µ)

Particulate Agents (Temporary)

• Avitene (100–150 µ)
• Gelfoam powder (40–60 µ)
• Gelfoam sponges (cut to size)
• Tantalum powder is mixed with Gelfoam to make it radio-opaque

Liquid Agents (Occluding, Sclerosing)

• Ethanol
• Thrombin
• Hypertonic glucose
• Sodium tetradecyl sulfate
• Ethibloc
• EVAL
• Onyx

Procedure Steps

• Planning, preparation, performance, and post-procedure care

Planning The Procedure

• Schedule for urgency priority using a biplane Angiography unit for cerebral angiography
• Premedication is needed if the patient is allergic to iodine
• Team availability of the radiologist, technologist, nurse
• Material availability of catheters, embolizing agent, needles, CM, angioplasty balloons, etc.
• Fasting: Clear liquid intake or NPO 8 hours before examination prevents vomiting - aspiration
• Blood test ordering, verify results (PT & PTT, INR, Platelet count, White blood cell count, Creatinine & eGFR)
• Contact nurse or referring physician for instructions on preparing for the examination
• Hydration protocol pre and post procedure
• Coordinate immediate dialysis if applicable
• Review previous images (local PACS and DSQ /RID) and any other available/applicable medical information about patient

Preparing for the Procedure (Day Of The Exam)

• Verification of equipment and instruments to be used (C-arm, AI, US & x-ray unit, monitors)
• Review previous images (local PACS and DSQ/RID)
• Patient preparation
  • ID the patient with at least two identifications (name, MRN, DOB, address)
  • Explanation of procedure
  • Explanation of risks (radiologist responsibility) and signing of consent form
  • CM questionnaire filled out - if allergic to CM then premedication is needed, hydration protocol if applicable
  • CM to be used
  • Vital signs (baseline)
  • IV installation if necessary
  • Shave the puncture site
  • Antibiotics and light sedation if needed (cocktail of Versed and fentanyl)
• Confirmed Blood results: Creatinine, GFR, PT, PTT, INR
• Team meeting to go over the procedure plan and safety checklist
• Prepare material that will be used: catheters, guidewires, introducer sheet, puncture needle, embolizing material, thrombolysis material

During the Procedure

• Communicate with patient to assess mental state, pain level, comfort level
• Continuous monitoring of vital signs; BP every 10 minutes
• Oxygen saturation: Administer oxygen if level falls below 90%
• Level of sedation verified: Consult radiologist if sedation wearing off
• Operation of radioscopic equipment: LIH, AEC, DSA, Road mapping, bolus chasing, fluoroscopy time
• Operation of automatic injector

After the Procedure

• Care of patient:
  • Venous femoral punctures: Apply direct pressure for less than 5 minutes maximum
  • Arterial femoral punctures: Apply direct pressure for 5 to 10 minutes, check site, then gradually decrease pressure over next 10 – 20 minutes
  • Minimum of 4-hour bed rest before discharge following procedure with extremity kept straight, head may be raised up to 30 degrees if needed
  • Pedal pulse of extremity on side of puncture taken every 15 minutes for the first hour, then every 30 minutes
  • Vital signs: Taken every 15 minutes for the first hour, then every 30 minutes
  • Alert for development of hematoma
  • Increase fluid intake for 24 hours and minimal activity for the remainder of the day
  • Patient cannot be discharged unless someone can take patient home

Post Angio Procedure Care

• When the study has been completed, the catheter is removed, if the catheter has a shaped tip, the guide wire must be reinserted to remove the catheter.
• Apply manual pressure to the puncture site until bleeding stops, and note any abnormal condition of the patient on the chart and notify the physician.
• Move the patient to a designated location and keep on bed rest for 4 hours minimum which includes:
  • recording the pulse on the side of entry four times during the first hour at 15-minute regular intervals and twice an hour for the remaining 3 hours.
  • Vital signs should be checked at these intervals and recorded on the patient's chart.
  • Puncture site observed as part of the monitoring process for possible internal or external bleeding.
• The patient should be urged to take fluids by mouth even if intravenous hydration is being applied. If the patient appears to be stable after the prescribed period of bed rest and has someone who can care for him or her for a 24-hour period, the patient can be discharged.

Risks of Angiography

• Relatively safe procedure
• Major risk categories: catheterization and CM
• Catheterization complications include bleeding, thrombus formation, cholesterol embolization, pseudoaneurysm, arterial dissection, and rupture of an aneurysm
• Cardiac, renal, or neurologic blood flow can be compromised, resulting in ischemia, permanent organ damage, or death
• Continuous monitoring of vital signs and pulse can provide an early warning of complications
• Communicate effectively with personnel involved with the patient’s care before, during and post procedure, if applicable

Other Post Procedure Tasks

• Image Quality Control
  • DSA images (pixel shifting & remasking)
  • Reconstruction if applicable
• Selection of images to send to PACS
• Documentation of PROCEDURE in RIS and patient’s medical Chart if applicable
• Clean up the room

This lesson covers key concepts related to vascular access devices, catheters, and angiographic procedures, including needle gauges, guidewire properties, catheter types, and procedural considerations. It emphasizes the importance of communication with the patient during angiography. It also covers visceral regions during operations.