Interventional Radiology: BasicsRam Gurajala

Interventional Radiology

What is Interventional Radiology?

Sub specialty of Radiology

Image-Guided Surgery or Surgical Radiology

Performing minimally invasive therapies under imaging guidance.

Some of these procedures are done for purely diagnostic purposes (e.g., angiogram), while others are done for treatment purposes (e.g., angioplasty).

MINIMAL ACCESS – MAXIMUM RESULT

Who are Interventional Radiologists?

Physicians who specialize in minimally invasive, targeted diagnosis and treatments.

Offer the most in-depth knowledge of disease processes using least invasive methods of advanced diagnosis in complex ailments and treatments

Via pin-hole accesses. Externally, there is no more than a tiny scar at the pin hole marking the site of access.

They require strong diagnostic and clinical experience across several fields of medicine in all age groups.

They use X-rays, MRI, CAT/CT, ultrasound and other imaging modalities.

What do we do?

Vascular/angiography

Peripheral Vascular Disease

Interventional Oncology

Gastrointestinal, Genitourinary, Hepatobiliary

Women’s health

Biopsies and Drainages

Musculoskeletal

Neurointerventional

What's in Interventional radiology?

These procedures can replace certain surgeries:

Faster recuperation than with surgery

Usually no hospital admission required (done as an outpatient)

Local anesthetic or moderate sedation can be used instead of general anesthesia for majority of the procedures.

Safe and effective

History1929: Dr Werner Forssmann accessed

the heart from the peripheral circulation using a catheter

1964: Dr Charles Dotter performed the 1 st peripheral angioplasty

1977: Dr Andreas Grutzig performed the 1 st percutaneous transluminal coronary angioplasty

The balloon catheter was first used to perform PTCA in 1977, which led to many subsequent advances in the field of interventional cardiology

1977: Beginning of Angioplasty era

1994: Beginning of the stent era

2002: Beginning of the DES era

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=341888 http://www.nobel-winners.com/Medicine/werner_forssmann.htm www.ohsu.edu/dotter/images/ctdotter.jpg

Basics

Patient preparation

Contrast media

Needles, Sheaths, Wires

Catheters, Balloons and inflation devices

Stents

Drainages and percutaneous biopsy

IVC Filters

Gastrointestinal access catheters

Central venous catheters

Embolization

Equipment (Ultrasound, Fluoroscopy, Cone beam CT, CT)

Patient Preparation

Consent

Skin Preparation

Antibiotic prophylaxis

Local Anesthetic

Sedation

Anticoagulation

Boring but Important!

Contrast media

Osmolarity

Reactions: Flushing, metallic taste, headache

Pain/warmth particularly uncomfortable for direct arterial injections in medium/small vessels

Allows better grey scale visualisation

Contrast injection

Non-selective angiography

Selective angiography

Flow rates

Injector pumps

Alternatives: CO2, Gadolinium

Contrast induced nephropathy(CIN)

CRF common in patients undergoing angiographic procedures.

CIN is common following contrast :

Have pre-existing CRF

Diabetes

Multiple myeloma

CCF

Elderly

High dose examination.

Anaphylactic reactions

Incidence (LOCM): 0.04% 1 in 2500

0.004%-very serious reactions

Know the protocols- Go on a course (it’s changed a lot recently!) Know where your crash trolleys are.

High risk patients:- Use something else

Steroid prophylaxis?

PO/IV?

Must be started 24 hours prior to administration.

Test dose (need to wait for 30 minutes)

NeedlesTwo types for vascular needles

One part

Single wall puncture (in theory!)

More traumatic to vessel wall

More important consideration with antegradepunctures

More likely to induce dissection?

Two part

Less traumatic

inevitable 2 wall puncture

Needle size

Needle gauge is inversely proportional to diameter

10 gauge= 3.4mm

15gauge=1.8mm

20gauge= 0.92mm

It does not tell you the internal diameter

Wires Measured in imperial inches

Hundreds of types

Two typesHydrophillicMetal

Guide wiresDesigned to have an a-traumatic tip to prevent

damage of the vessel

3 basic tip shapesJ tip is atraumaticAngled is for irregular strictures-to steer roundStraight is for smooth strictures or smooth vessels

Shaft:gives its flexibilitygives its torsional rigidity or push

SheathsTypes:

StandardShaped“Armoured”

Measured in ‘French’Refers to outside circumference

ComponentsA introducer/dilatorThe shaft of the sheathA haemostatic valveA side arm with tap

AdvantagesMore comfortableLess traumatic

Disadvantages: Inevitable larger hole on arteryMay reduce flow in critically narrowed vesselsMay not be room for sheath

Catheters

Types of catheters:

Non selective

Selective

Flushing

Hundreds of catheters

Choosing a selective catheter

Guiding catheters

Superselective catheterisation:

Microcatheters

BalloonsThe basic tool for angioplasty

Dual lumen catheter – guidewire and inflate/deflate lumen

Variable catheter shaft lengths 75 – 120cm

CharacteristicsDiameter - when inflated Length – Indicated by radio-opaque markers

Choosing a balloonLengthShaft

Types:ComplianceHigh pressureMono railCutting

Inflation device

Allows you to achieve correct pressure within the balloon

Rated burst pressure (RBP): At least 99.9% of the balloons (with a 95% confidence)

will not burst at or below their rated burst pressure

Graduated plastic syringe

Plunger on a screw thread

Locking device

Pressure gauge

Connecting tube

StentsAn expandable wire form or perforated tube

inserted into a natural conduit

To prevent or counter act a disease induced localized flow constriction

Types:Metal- balloon or self expandingCovered metal - stent graftsDrug elutingBio absorbablePlastic Fenestrated and branched EVAR

Ideal Stent:Low profileHigh radioopacityFlexible but strongResistant to thrombosis/intimal hyperplasiaMR compatibleCheap

Non Vascular Stents

Choosing an Arterial stent: Strength -balloon >self expandingPrecise positioning - balloon=self expandingConformability - self expandingRisk of compression-(carotid/popliteal)-self

expanding Short lesions –balloon expanding Long lesions –self expanding

Arterial Stenting –Tips:Balloon mounted –pre dilate or use long sheath

Self expanding –may extrude forwards

Over bifuraction approach –use long sheath

Guide to safe stenting: Angiogram centred over deployment area Identify landmarks or use road map Measure lesion length + diameter Position stent Check angiogram with stent in position Deploy under continuous fluoroscopy Balloon stent,completion angio,check run off Remove delivery system under fluro

Secondary arterial stenting:Failed PTA

Residual stenosis

Flow limiting dissection

Thrombus

Arterial rupture

Drainages and biopsy

Drainage procedures:

Simple and complex collections – chest, abdomen and pelvis

US, CT, Fluoroscopic guidance

Drainage equipment

Planning:

Shortest, safest, most dependent position

Avoid blood vessels, bowel

Assess the nature of the collection (septations)

Needle? Catheter ? Guide wire? Dilator? Lock?

22g needle

6F-24F catheters Locking or non-locking

Guidewires Rigid enough to guide dilator/catheter

Able to coil within abscess

Short for convenient use

Heavy duty/von Rosen/Amplatz

Dilator

Lock

Secure

Aspirate/Drainage

Percutaneous biopsy

Co-axial needles

Biopsy needles

Visualisation US/CT/Fluoroscopy guidance

IVC Filters

Contraindications:MegacavadiameterVCI > 30 mm No approachNo spaceHypercoagulopathy e.g. proteinC-deficiencyfibrinolysis

Absolute Indications (Proven VTE)Recurrent VTE –acute or chronic –despite

adequate AC

Contraindication to AC

Complication of AC

Inability to achieve/maintain therapeutic AC

Prophylactic Indications (no VTE, primary prophylaxis not feasible)

Trauma patient with high risk of VTE

Surgical procedure in patient at high risk of VTE

Medical condition with high risk of VTE

Relative Indications (proven VTE)

Iliocaval DVT

Large, free-floating proximal DVT

Difficulty establishing therapeutic AC

Massive PE treated with thrombolysis/ thrombectomy

Chronic PE treated with pulmonary artery thrombendarterectomy

Thrombolysis for iliocaval DVT

VTE with limited cardiopulmonary reserve

Recurrent PE with filter in place

Poor compliance with AC medications

High risk of complication of AC (such as ataxia or frequent falls)

When to Use a Retrievable Vena Cava FilterThe risk of clinically significant pulmonary

embolism is transient.

The contraindication to anticoagulant medications is transient.

Life expectancy of at least six months.

Gastrointestinal access catheters

Indications Short term

Long term

Approach Anatomy

NG tube

Access Kit

US, Fluro, Dyna CT guidance

Safety

Central Venous Access

Tunneled HICKMAN

LEONARD

TDC (TUNNELED DYALYSIS CATHETER)

TRANSLUMBAR

TRANSHEPATIC

APHERSIS

PORT

HOHN

Guidance:

US, Fluoro, Cone beam CT

Non-tunneled QUINTION

PICC

TRYALYSIS

CVP

Embolisation

The goal:

To reduce the blood pressure at the bleeding site

allow a stable clot to form without causing tissue ischemia or necrosis.

Risks:

cannot be retrieved once they are released.

Occlusion of a vessel or vascular territory

PurposeControl of haemorrhagePrevention of complicationCell deathObliteration of functionDrug delivery

Routes of approachTrans-arterialRetrograde trans-venousDirect puncture

Embolic agentsParticlesClot

Suture

Gelfoam

PVA

Spheres

CoilsMicrocoils

Fibred

Detach

GDCLiquidsAlcohol

IBCA

OnyxBalloons

Equipment

Advanced Applications in IR

Did I include All IR?

MSK

Neuro

Other: Sclerotherapy

Lymphangiogram and embo

Thrombectomy

The LIST GOES ON AS IR IS ALWAYS READY TO ACCEPT CHALLENGES AND ASSIST IN THE MANAGEMENT OF PATIENT CARE

Summary

One session, in fact fellowship is not sufficient to understand all about IR

Practical knowledge of basic understanding of the tools, equipment and their availability is a necessity

Each case is a challenge, which can range from simple to complex.

Better planning of the cases is always an advantage

Finally, Who are we?Specialists in performing minimally invasive, targeted diagnosis and treatments, using X-rays, MRI,

CAT/CT, ultrasound and other imaging modalities.

We have the most in-depth knowledge of disease processes using least invasive methods of advanced diagnosis in complex ailments and treatments

Majority of cases, all we leave is no more than a tiny scar marking the site of access.

MINIMAL ACCESS – MAXIMUM RESULT