TRANSESOPHAGEAL ECHOCARDIOGRAPHY

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TRANSESOPHAGEAL ECHOCARDIOGRAPHY
Dr. Richa Jain
University College of Medical Science GTB
Hospital, Delhi
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TRANSESOPHAGEAL ECHOCARDIOGRAPHY

• Introduction
• Equipment
• Advantages
• Disadvantages
• Procedure
• Indications
• Contraindications
• Complications
• Clinical uses

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INTRODUCTION

• In 1976, Dr Leon Frazin - concept of TEE.
• Echocardiography- the heart and great vessels
  probed with ultrasound (sound with frequency
  above 20 kHz).
• Echocardiography uses ultrasound waves with
  frequency of 2.5 7.5 MHz.
• Ultrasound sent into thoracic cavity and
  partially reflected by cardiac structures.
• From these reflections distance, velocity and
  density of objects within the chest derived.

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INTRODUCTION
ULTRASOUND WAVE AND ITS CHARACTERISTICS.
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IMAGING TECHNIQUES

• M MODE
• One-dimensional views of cardiac structures
  produced by single-crystal transducers .
• Density and position of all tissues in the path
  of a narrow ultrasound beam displayed as a scroll
  .
• It is a timed motion display.
• Principally used to view rapidly moving
  structures eg. valve leaflets.
• Disadvantages orientation and interpretation of
  spatial relationships difficult.

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M-mode transesophageal echocardiogram of a normal
aortic valve
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IMAGING TECHNIQUES

• 2D MODE
• Rapid, repetitive scanning along many different
  radii within an area in the shape of a fan
  (sector).
• A live (real time image) of heart is produced.
• Advantage the image obtained resembles an
  anatomic section and can be easily interpreted.

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• two-dimensional cross section of a normal aortic
  valve (AV)..

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IMAGING TECHNIQUES

• DOPPLER TECHNIQUE-
• Based on doppler principle.
• With doppler, blood flow velocity can be
  measured.
• Different types of Doppler techniques
• Pulsed wave doppler
• Continuous wave doppler
• Colour flow doppler

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Different types of doppler technique

• 1. Pulsed wave doppler-
• A small sampling volume (cursor) is placed in an
  area of interest with a 2D image.
• Adv measures blood flow velocities at selected
  areas of interest 3-5 mm wide along the
  ultrasound scan line.
• Disadv cannot measure fast blood flow
  velocities(gt1m/s).
• Use to measure blood flow velocities through the
  pulmonary veins and mitral valve.

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Pulsed wave Doppler echocardiogram of the main
pulmonary artery (MPA).
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Different types of doppler technique

• 2. Continuous wave doppler-
• Uses two sets of separate crystals one to
  continuously emit ultrasound and one to
  continuously receive it.
• Adv detects blood flow velocities upto 7m/s.
• Disadv cannot identify location of the peak
  velocity
• Use to measure blood flow velocities through
  aorta, aortic valve,regurgitant valvular jets
  etc.

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Continuous wave Doppler (CWD) of regurgitant
mitral valve.
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Different types of doppler technique

• 3. Colour flow doppler -
• Based on principle of PWD.
• Uses multiple sample volumes along a scan line.
• A colour code assigned to depict flow toward
  (red) and away (blue) from the transducer.
• 2 colour flow patterns
• Normal aliasing pattern due to laminar blood
  flow (as an area of homogenous color surface)
• Mosaic pattern due to turbulent blood flow ( as
  a mixture or mosaic of colour patterns known as
  colour jets)

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Different types of doppler technique
Normal color Doppler aliasing
Mosaic pattern
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Different types of doppler technique

• Colour doppler flow
• Adv presents the spatial relationships between
  structure and blood flow.
• Disadv like PWD, it cannot measure fast blood
  flow velocities.
• Use to enhance recognition of valvular
  abnormalities, aortic dissections, and
  intracardiac shunts.

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Different types of doppler technique

• TISSUE DOPPLER
• A new use of PWD technology
• To measure myocardial velocity.
• It measures the velocity of the descent of the
  mitral annulus (Sm) towards the apex of the heart
  during normal LV contraction.
• It decreases in presence of myocardial ischemia.

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TEE EQUIPMENT

• Monitor and TEE probe
• TEE probe a minaturized echocardiographic
  transducer (40mm long, 13mm wide and 11 mm thick)
  mounted on the tip of a gastroscpoe.
• Transducer a phased array configuration with 64
  piezoelectric elements operating at 3.7 to 7.5
  MHz.
• 2 knobs one controls anteflexion and
  retroflexion other controls rightward and
  leftward movement of the probe.
• One electronic switch to scan the heart in
  various axial views .

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ADVANTAGES OF TEE
Transducer 2-3 mm from heart high resolution image better image quality
Closer to posterior structures better visualization of LA,MV, LV, PV, Aorta etc.
Far from surgical field intraoperative monitoring
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DISADVANTAGES OF TEE

• Semi invasive procedure chances of injury
• Needs special set up, technique, preparation,
  instrumentation
• Needs orientation and expertise

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PROCEDURE

• Induction of anaesthesia and tracheal intubation
• Patients neck extended
• Well lubricated TEE probe introduced into the
  midline of hypopharynx with transducer facing
  anteriorly
• Probe advanced into esophagus
• During this manoeuvre, the control knob must be
  in neutral position.

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Terminology used to describe transesophageal
echocardiography probe movements.  
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I III II
I- UPPER ESOPHAGEAL II- MID ESOPHAGEAL III-
TRANSGASTRIC
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Transesophageal echocardiography cross sections
in a comprehensive examination.
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INDICATIONS FOR PERIOPERATIVE TEE

• Preoperative hemodynamically unstable patients
  with suspected thoracic aortic aneurysms,
  dissection, or disruption
• Intraoperative
• acute, persistent, and life-threatening
  hemodynamic disturbances
• valve repair, CHD surgery for lesions requiring
  cardiopulmonary bypass repair of hypertrophic
  obstructive cardiomyopathy endocarditis repair
  of aortic dissections pericardial window
  procedures.

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INDICATIONS FOR PERIOPERATIVE TEE

• In ICU unstable patients with unexplained
  hemodynamic disturbances, suspected valve
  disease, or thromboembolic problems.

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CONTRAINDICATIONS OF TEE

• ABSOLUTE
• Previous esophagectomy
• Severe esophageal obstruction
• Esophageal perforation
• Ongoing esophageal haemorrhage
• RELATIVE
• Esophageal diseases-diverticulum, varices,
  fistula
• Previous esophageal surgery
• Previous mediastinal irradiation
• Unexplained swallowing difficulty

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COMPLICATIONS OF TEE

• Oral and pharyngeal injuries (0.1 0.3)
• Transient hoarseness (0.1 12)
• Esophageal injuries
• Splenic injuries 2 case reports
• Endocarditis in outpatients

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CLINICAL USES

• EVALUATION OF LV FILLING
• TEE reveals changes in left ventricular preload
  and filling pressure.
• It measures EDA (end diastolic volume).
  EDA lt 12cm2 - hypovolemia
• Assessment of LV filling and function
  subjectively with the trained eye a valid
  method to guide fluid administration.
• Kuecherer a systolic fraction of pulmonary
  venous flow lt 55 - a sensitive and specific sign
  of LAP gt 15mmH. ( as predominance of flow during
  diastole).

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CLINICAL USES

• 2. ESTIMATION OF CARDIAC OUTPUT
• Real-time TEE images of LV filling and ejection
  permits qualitative, immediate detection of
  extreme changes in cardiac output.
• TEE quantify CO the velocity and the
  cross-sectional area of blood flow.
• SV v x ET x CSA
  
  SV
  stroke volume (ml)
  v
  spatial average velocity of blood flow (cm/sec)
  ET systolic ejection time
  (sec)
  CSA cross-sectional area of the vessel (cm2
  )

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CLINICAL USES

• 3. Assessment of ventricular systolic function
• Fractional area change (FAC) during systole a
  measure of global LV function.
• FAC EDA ESA / EDA
• EDA cross-sectional area at end diastole
• ESA cross-sectional area at end systole.
• Marked changes in FAC are apparent by simply
  viewing the real-time images.
• Hallmarks of severe RV dysfunction severe
  hypokinesis , enlargement of RV , change in shape
  of RV from crescent to round.

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CLINICAL USES

• 4. Assessment of ventricular diastolic function
• TEE is an ideal tool for assessment of diastolic
  function because of its unobstructed view of the
  mitral valve and pulmonary veins.
• Normal flow across the mitral valve in diastole
  has
• E wave an early higher-velocity component
  (generated by atrial pressure and ventricular
  relaxation)
• A wave lower-velocity component (generated by
  atrial contraction)
• At slower heart rates, these two waves are
  separated by a period of relatively little flow
  (diastasis).

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Line drawings representing simultaneous
transesophageal pulsed wave Doppler recordings
from the mitral annulus and right upper pulmonary
vein.
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CLINICAL USES

• 5. Detection of myocardial ischemia
• Acute myocardial ischaemia produce abnormal
  inward motion and thickening of affected
  myocardium.
• Short axis view of LV at level of papillary
  muscle best view
• Wall thickening more specific marker than wall
  motion.

CLASS OF MOTION CHANGE IN RADIUS
NORMAL gt30 decreased
MILD HYPOKINESIS 10 30 decreased
SEVERE HYPOKINESIS 0 10 decreased
AKINESIS None
DYSKINESIS Increased
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REFERENCES

• Ronald .D. Miller Transesophageal
  echocardiography. Millers Anaesthesia 7 th
  edition, 2010 1329-1356.
• Intraoperative echocardiography. Kaplans cardiac
  anaesthesia 3rd edition.

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