Cardiac Catheterization

4 types of info rendered from cardiac catheterization:

• Cardiovascular pressure readings

• Blood flow determination

• Angiography

  • visualization of cardiac / vascular structures

• Electrophysiological studies

Cardiac Cath Personnel

• There will be many people in the Cath lab during a procedure

• some will be sterile while others will not

• when you are in the lab, be prepared to wear a lead shield / apron

• must work as a team!

Cardiac Cath Physician

Well trained Cardiologist

Cardiac Cath Nurses

• Prepare and monitor the pt

• give med’s

• prepare instruments / catheters

Cardiac Cath X-ray tech

• special procedures

• fluoroscopy

Hemodynamic assessment:

• Rt heart Cath

  • access vein (Femoral, Brachial, Subclavian)

  • pass cath through IVC into the RA and RV

When doing a rt heart cath, (1) do pressure measurements of:

• RA

• RVSP

• RVEDP

• mean PA

• SPAP

• PAEDP

• Pulmonary-Capillary Wedge

What precent of the left heart pressure is the right heart?

The rt heart pressure is 20% of the lt heart

When doing a rt heart cath, you take blood samples to check the oxygen saturation of:

• SVC

• IVC

• RA

• RV

• MPA

Left Heart Cath

• more difficult b/c assessing A instead of V

• pass catheter through Aorta into the LV

When doing a lt heart cath, you take pressure measurements of:

• LVSP

• LVEDP

• mean Ao

• systolic Ao

• diastolic Ao

• NO LA pressure taken

With a lt heart cath, the ventriculography / LV angiography will evaluate:

• assess LV function

• severity of MR

• shunt flow

  • aka: VSD / ASK

  • hole or communication between right and left heart

During a lt heart cath, a Coronary Arteriography / Angiography is placed:

• pass catheter through Aorta into the ostium of the CA’s

  • at the sinus of valsalva

During a lt heart cath, an aortic root angiography is the assessment of:

• Aortic aneurysms / dissection

• AI

• AS

Electrophysiological studies

• testing of Cardiac Pacing

• Tx of arrhythmias

Interventional / Special Techniques

• PTCA

• myocardial biopsy

• balloon balvuloplasty

• catheter ablation

  • irritable foci and accessory pathways are terminated

Electrophysical studies

• testing of Cardiac Pacing

• Tx of arrhythmias

Examples of Interventional / Special Techniques:

• PTCA

  • percutaneous transluminal coronary angioplasty

• myocardial biopsy

• balloon valvuloplasty

• catheter ablation

  • irritable foci and accessory pathways are terminated

Indications for a cardiac catheter:

• CAD

• MI

• Valvular heart disease

• Congenital heart disease

• Ao disease / dissection

• Pulmonary angiography

• Cardiomyopathy

• Pericardial constriction / fluid

• Pre- and s/p Cardiac transplant

Coronary Artery Disease (CAD)

atherosclerotic plaque blockage of the CA’s leading to insufficient blood flow to the myocardium

Symptoms of CAD:

• angina (chest pain)

• silent ischemia

• CHF

• positive stress test (EKG or Echo)

Contra-indications for a cardiac catheter:

• fever / infection

• anemia

• hemorrhage

• hypercoaguable state

• shock

• hypoxia

• uncooperative pt

  • dementia

Contra-indications for a cardiac catheter:

• pregnancy

  • no X-ray

• renal failure

  • can’t rid of contrast

• technical reasons

  • failed vascular access

    • calcified vessel

Cardiac Cath Pt Prep:

• explain procedure

  • should be MD’s responsibility

• Pre-Admission Testing

  • 12 lead EKG

  • Labs:

    • creatinine

    • BUN

    • prothrombin time

Cardiac Cath Pt Prep:

• Obtain informed consent

  • pt understands the risks and benefits of the procedure

• AKA to medications

• Pt fasting from midnight prior

• before pt comes to lab:

  • IV access

  • remove dentures / eyeglasses

  • shave groin area

Cardiac Cath Pt Prep:

• Pre-Cath sedation

  • valium or demoral

    • if very anxious about the procedure

• Lab set up

  • check crash cart supplies

  • run cinefilm

    • check current pt ID

  • sterile trays / equipment

    • needle

    • guide wire

    • catheter

    • med’s

Cardiac Cath Pt Prep:

• Attach EKG electrodes

• Explain procedures such as:

• Clean and drape entrance site

Entrance sites of cardiac catheter insertions:

• Femoral

• Subclavian

• Brachial (more vasc complications associated)

• Radial → becoming more and more popular

• Arm, Wrist, and/or Groin

Procedure and Protocol:

• monitor pt

  • check pt’s vital signs

• maintain records

  • puncture sites

  • types and gauge of catheter

  • pressure recordings

  • time/dosage of med’s

Procedure and Protocol:

• Pt supine

  • radiolucent, padded operating tavle

  • X-ray equipment

• sterile technique

  • surgical scrub

  • scrub suits, gloves, mask, booties

• radiation precautions

  • lead apron

    • do not go in if pregnant

  • radiation badges

Insertion steps:

• clean and drape access site

• inject local anesthetic

• needle inserted to puncture site

• guide wire fed through needle

  • used to avoid vessel damage

  • done w/ fluoroscopy to observe progress

    • real time x-ray

  • little sensation to pt

• remove needle and apply pressure

• vessel dilator inserted and removed

• insert catheter over guide wire

• remove guide wire

Following the cath procedure:

• monitor pt’s clinical S&S’s

  • pt placed in holding area for a few hours

• apply pressure to entrance site

  • 10-15 minutes

  • pt should not bend affected extremity

    • 4-6 hrs

• enter all procedure notes on pt chart

Cardiac Cath Complications:

• there are risks involved

  • morality rate: 3-4 / 1000 pts

  • always be performed by well trained physician / staff

  • up-to-date equipment

• risks need to be weighed against possible procedure benefits

Possible complications:

• Death

• MI

• Arrhythmia

• Vascular injury

  • pseudoaneurysm, AV fistula

• Cardiac perforation

  • may cause Cardiac Tamponade

    • severe pericardial effusiion

• Septal defects

  • ASK or VSD

• Allergic reaction to contrast media

Hemodynamic Data

• By using a fluid filled catheter, it is possible to determine pressures at almost any circulation site

• remember: fluid flows from a high to low pressure area

RA pressure AKA:

• Central Venous pressure

RA pressure

• represents the filling pressure of the RV

• 2-7 (0-5) mmHg

What is RA pressure normally equal to?

RVEDP

What causes elevated Central Venous pressure?

• increased RVEDP

• TS (Tricuspid Stenosis)

  • causes outflow obsruction from RA to RV

RV End Diastolic pressure (RVEDP)

• 2-6 mmHg

• increased RVEDP causes:

  • increased RA pressure

RV Systolic pressure (RVSP)

• 25 mmHg

• RVSP increases w/ pressure overload

RVSP pressure overload is caused by:

• Increased right-sided outflow resistance d/t:

  • Pulmonary stenosis (PS)

  • PHTN

SPAP

25 mmHg

DPAP

10-12 mmHg

Mean PAP

16 mmHg

There is an increase in Pulmonary Artery pressure (PAP) with:

• Pulmonary vascular obstruction

  • COPD

  • pulmonary embolism

• increased Pulmonary Capillary pressure

  • PHTN

  • Lt heart disease

Pulmonary Capillary pressure (PCP) AKA:

Pulmonary Capillary “wedge pressure” (PCWP) → b/c cath is wedged (via balloon on cath tip) into PA

Pulmonary Capillary pressure (PCP)

• mean pressure - 10-12 mmHg

• in pt’s with normal pulmonary symptoms:

  • PCP will approximate LA pressure

    • we cannot get a direct measure of the LA

Elevated pulmonary capillary pressure is a result of:

Mitral Stenosis

LA pressure

• represents the filling pressure of the LV

• mean - 10-12 mmHg

Elevated LA pressure is due to:

• MS

• Increased LVEDP

As LA pressure increases:

• So does PCP

  • PAP next

  • then RVSP

  • then RA pressure

LV end-diastolic pressure (LVEDP)

10-12 mmHg

What causes LVEDP to increase?

• dyastolic dysfunction

  • “relaxation” problems due to:

    • CAD & ischemia w/ resultant scarring

    • CHF

    • toxic (alcohol) damage (DCM)

    • constrictive pericarditis

    • MV and AoV insufficiency

What results from increased LVEDP?

• Increased LA pressure

  • therefore PCP, PAP, etc.

LV Systolic pressure (LVSP)

• 120 mmHg

• without AoV abnormalities:

  • LVSP will equal systolic BP

    • found w/ brachial BP cuff

Elevated LVSP is due to:

• systemic HTN

  • most common cause

• Atrial Stenosis (AS)

Systolic Aortic pressure (SAP)

120 mmHg

Diastolic Aortic Pressure (DAP)

80 mmHg

Mean Aortic Pressure (AP)

92 mmHg

Pressure Gradient

• difference in pressure between two chambers

• necessary for blood flow

What is the most accurate means of evaluating valvular function?

Pressure gradients across a valve

3 ways Cath measures pressure gradients:

1. Peak to Peak PG

   1. always slightly lower than peak instantaneous

1. Peak instantaneous PG

   1. always slightly higher than peak to peak

2. Mean PG

Peak to Peak PG

• represents difference between peak systolic pressures at two different locations, regardless of where they occur in the cardiac cycle

  • example: compare LVSP to Ao systolic pressure ( or RVSP to SPAP) to determine severity of semilunar valve stenosis

• reported from the Cath Lab only

Peak instantaneous PG (Max PG)

• represents pressures at two different locations at the same time during the cardiac cycle

• can be reported from the Echo Lab too

  • trace the spectral waveform obtained across a valve

True or False. Measurements reported in both Cath and Echo should be closely correlated.

True

Cardiac Output (CO)

• the volume of blood ejected by the heart per minute

• gives information about the amount of blood in circulation

Normal resting CO:

4-8 L/min

CO=

SV x HR

Stroke Volume (SV)

• the difference between end diastole and end systole volume per beat

• volume of blood ejected from the heart w/ each contraction

Heart Rate

Number of ventricular contractions per minute

Cardiac Index

• CO is used to find the CI

• CO expressed in relation to the pt’s body surface area (BSA)

  • CO / square meters of BSA

Normal cardiac index:

2.76 - 3.6 L/min/m²

3 methods to determine CO in the Cath Lab:

All are based on the Fick Principle

1. Fick Method

2. Indicator Dilution Technique

3. Thermodilution Technique

Fick Principle

In a closed steady-state system (heart and vessels), the amount of Indicator flowing into the system equals the amount of Indicator flowing out of the system

Fick Method

• Oxygen is used as the Indicator

• requires 3 pieces of data:

  • oxygen consumption

    • amt of O₂ taken up by the body

    • determined by having the pt breath into a mask to collect the expired air

  • oxygen content of arterial blood

  • oxygen content of venous blood

• O₂ consumption / A-V content

Indicator Dilution Technique

• Indocyanine Green dye

  • dye is injected into the right heart and the concentration of the dye is them measured on the arterial side w/ a Densitometer

• Rarely used

What was the Indicator Dilution Technique replaced with?

Thermodilution Technique

Thermodilution Technique

• utilizes a decrease in blood temp as the thermal Indicator

  • chilled saline is injected into the right heart and the difference is measured on the arterial side w/ a thermistor

O₂ Sats

Amount of oxygen contained in blood

Right Heart O₂ Sats:

• = 75%

  • IVC

  • RA

  • RV

  • MPA

Left Heart O₂ Sats:

• = 95%

  • LA

  • LV

  • Ao

Oxygen Step-up

• Cath Lab will check for this

• a “step-up” in the right heart will indicate a shunt from the left heart increased the amount of O₂ present

Angiography

• Contrast media is injected into the blood

  • causes the blood to appear as a radiopaque area under fluorosopy

    • a silhouette of the chamber or vessel containing the media will be seen

    • will aid in the assessment of:

      • chamber / vessel size

      • stenosis

      • contraction

Selective Angiography

• dye injection is done only near the area from which the info is desired

  • not circulated through the entire system

• used generally for 4 areas

  • will help identify or R/o pathology in the specific area

Types of angiography:

1. Coronary angiography

   1. stenosis / occlusion of CA’s and branches

2. Left Ventriculography

   1. wall motion, EF, MR, VSD

3. Pulmonary Angiography

   1. pulm embolism

4. Aortography

   1. dissection, aneurysm, rupture, etc

Balloon Angioplasty

• may be utilized in:

  • PAD

  • CAD

    • alternative to CABG

    • the heart is like the extremities in the presence of stenosis

      • blood flow will not be able to increase enough w/ stress (exercise) to supply the muscle (myocardium)

      • results in constructive pericardium (CP)

What is the re-stenosis rate balloon angioplasty?

25-35%

Balloon Valvuloplasty

• same principle as balloon angioplasty

  • used to open up stenotic valves

• balloon tipped cath is inserted across the affected valve

• balloon inflated to stretch the valve orifice

Coronary Stents

• a metalic coil is mounted on the balloon tipped catheter

• when the balloon is inflated, the coil expands

• the balloon catheter is then withdrawn

• the coil stays in place to maintain vessel patency

Coronary Laser Angiography

• uses a fiber-optic catheter to destroy plaque formations

  • difficult to only vaporize plaque and not vessel wall

Rotoblater (roto-rooter)

Uses rotating drill type catheter to break plaque into microscopic pieces

Atherectomy Catheter

• the catheter tip contains a tube-like structure w/ a window in it

• the tube rotates to cut or shave off the plaque

• the plaque is collected in the tube

Endomyocardial Biopsy

• removal of heart tissue for diagnostic purposes

• will be performed to:

  • assess possible rejection following transplant

  • diagnose myocardial disorders

    • Hypertrophic cardiomyopathy (HCM)

    • myocarditis

Implantable Cardioverter-Defibrillator (ICD)

• act as a pacemaker, defibrillator, and cardioverter

• detect and prevent sudden cardiac arrest

• device works by detecting a dangerous rapid heart beat and then delivering a shock to help restore a normal rhythm

  • no more discomfort than being kicked in the chest

Where is the generator of the ICD placed in the chest?

Below the collarbone and the leads are placed in