Andrew Ronald

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When should you wriggle your TOEs in Theatre?

• Andrew Ronald
• Consultant Anaesthetist
• Aberdeen Royal Infirmary
• andrew.ronald_at_nhs.net

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Is there a role for Transoesophageal
Echocardiography (TOE) in Non-Cardiac Surgery?
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TOE in Non-Cardiac Surgery

• Introduction to TOE
• What does TOE tell us that other monitors dont
• Indications and Contraindications
• Can we identify Non-Cardiac Surgical patients who
  might benefit from TOE, and is there any evidence
  base to support that assertion?
• Are there disadvantages to TOE?
• When do I think we should consider using TOE

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A Brief History of TOE

• 1953/54 Edler Hertz - Ultrasound
  cardiography
• 1955/56 Yoshida - Doppler ultrasound to detect
  cardiac motion
• 1971 2D Echocardiography introduced
• 1974-76 Development of Transoesophageal
  Echocardiography (TOE)
• early 2000s Development of 3D-Echo
• 2006-2007 Introduction of real-time 3D TOE into
  clinical practice

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Physics of TOE

• Echo is very high frequency sound (2-10 MHz)
• follow physical laws of reflection and refraction
  and can be focused and orientated like beams
• reflected by dense materials and attenuated at
  depth
• propagates freely through liquids but poorly
  through air
• return of waveform signal dependant on structures
  it hits
• timed firing of multiple phased array of
  piezo-electric crystals can create a scanning
  front across area of interest

ffrequency cycles/sec Hz) ?wavelength cspeed
of sound in tissues and blood 1540m/sec f
1/T C f? Tissue penetration ? ?
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Physics of TOE

• US transducers on gastroscope body
• imaging from oesophagus
• insertion / withdrawl of probe
• anteflexion / retroflexion / lateral flexion
• rotation of US beam axis
• series of standard views recommended by ASA / SCA

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Modes of Echocardiography

• 2D echo
• M-mode
• Doppler
• 3D Echo

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2-Dimensional Echocardiography

• Conventional anatomical tomography of structures
  within field
• Real-time 2-D assessment of myocardial structure
  / function
• Frequency, beam width, pulse length transducer
  radius affect resolution
• Freeze / cine-loop enables off-line analysis

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M-mode Echocardiography

• Charts movements of structures along an
  interrogation line against time
• Useful for rapidly moving structures
• Useful for accurate measurements of cardiac
  dimensions

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Doppler Echocardiography

• Doppler echocardiography
• ..apparent change in received frequency due to
  relative motion between a sound source and sound
  receiver.
• ?Fd2FtVCos?/C
• Ft transmitted Doppler freq
• V blood flow
• Cos? cosine of angle between blood flow and US
  beam (Cos 0?1 Cos 90?0)
• C speed of sound in tissue
• ?P4V2

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3-Dimensional Echocardiography

• Until recently unavailable in real-time
• Involves acquisition of large amounts of data,
  only a fraction of which is actually used for 3DE
  reconstruction
• Allows visualisation of structures from multiple
  viewpoints

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TOE in Non-Cardiac Surgery

• What does TOE tell us that other monitors dont?

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What does TOE tell us?

• Dynamic Real-Time Anatomy, Physiology and
  Pathology
• Dynamic Cardiac Function
• You can see the heart and the proximal great
  vessels
• Changes in wall motion precede all other signs of
  ischaemia
• Monitor response to interventions directly
• Direct measurement / monitoring of systolic
  diastolic function
• FAC, FS, EF, SV, CO
• Dynamic Valvular function
• Normal / Abnormal
• Tailor management to abnormality
• Monitor response to interventions directly

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What does TOE tell us?

• ..a picture is worth a thousand words..

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TOE in Non-Cardiac Surgery

• Indications Contraindications

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Contraindications to TOE

• Absolute Contraindications
• Cardiac practice - probably no absolute
  contraindications
• Non-cardiac practice - gastro-oesophageal surgery
• Relative Contraindications
• varices
• oesophageal tumour
• UGI bleeding
• Use with care
• dysphagia
• hiatus hernia
• anticoagulation

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• Category I indications
• supported by strongest evidence / expert opinion
• TOE frequently useful in improving outcome
• Category II indications
• supported by weaker evidence / expert opinion
• TOE may be useful in improving outcome
• Category III indications
• little current evidence / expert opinion
• TOE infrequently useful in improving outcome
• Do any of the general indications identified for
  Cardiac Surgery extrapolate to Non-Cardiac
  surgery?

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What is a Category I indication?

• Evaluation of acute, persistent, life
  threatening haemodynamic function in patients in
  whom ventricular function and its determinants
  are uncertain and who have not responded to
  treatment
• TOE frequently useful in improving outcome

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What is a Category II indication?

• Perioperative use in patients at increased risk
  of myocardial ischaemia / infarction,
  haemodynamic disturbance or cardiac trauma
• TOE may be useful in improving outcomes

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Why is TOE useful in patients with ? risk of
myocardial ischaemia / infarction

• Regional wall motion abnormalities precede ECG
  changes so myocardial ischaemia recognised early
• Indirect evidence that early Rx of myocardial
  ischaemia and MI improves outcomes

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Why is TOE useful in patients with ? risk of
haemodynamic disturbance?

• Quantitative assessment of ventricular dimensions
  enhances conventional monitoring
• Better assessment of pre-load (EDV) than PAC

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Why is TOE useful in patients with(Cardiac)
Trauma?

• (Usefulness of TOE in diagnosing Thoracic Aortic
  injuries well recognised)
• Shortcomings of other methods of assessing
  adequacy of LV filling well recognised
• Facilitates direct assessment of myocardial
  filling / emptying and obstructions to these
  e.g. tamponade
• (Facilitates direct assessment of cardiac valve
  competency and myocardial thickening)

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Can we identify patients from a non-cardiac
surgical population who in theory at least might
benefit from TOE?
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Category I Indications

• Probably a bit of a no-brainer
• Evaluation of acute, persistent, life
  threatening haemodynamic function in which
  ventricular function and its determinants are
  uncertain and have not responded to treatment
• ACC / AHA / ASE 2003 Guideline Update on the
  Clinical Application of Echocardiography
• Emergency use to determine the cause of an acute
  persistent and life-threatening haemodynamic
  disturbance
• Recommendation in 2007 ACC / AHA Guideline on
  Perioperative Cardiovascular Evaluation and Care
  for Non-Cardiac Surgery (Circulation 2007 116
  e418-e500)

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Category II indications

• Increased risk of myocardial ischaemia /
  infarction
• Increased risk of haemodynamic disturbance
• How do we identify these patients most at risk
  who might benefit?
• More more difficult!

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Revised Cardiac Risk IndexLee et al Circulation
1999 100 1043-1049

• Major risk factors
• High-risk type of surgery
• History of Ischaemic heart disease
• History of Congestive heart failure
• History of Cerebrovascular disease
• Preoperative Rx with Insulin
• Preoperative Serum Creatinine gt 2mg/dl
  (180 ?mol/l)

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• Cardiac Risk Indexes
• May give us some sort of starting point - but
  what is it?
• Do we TOE everyone with gt3 risk factors?
• Clearly impractical large numbers
• Tells us nothing on changing outcomes
• The question remains, at what level of risk do we
  consider perioperative TOE?
• Does it influence our outcomes in non-cardiac
  surgery?

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• Intraoperative transoesophageal echocardiography
  during non-cardiac surgery
• Suriani RJ et al. J Cardioth Vasc Anesth 1998
  12 274-280
• Perioperative use of transoesophageal
  Echocardiography by Anesthesiologists impact in
  non-cardiac surgery and in the intensive care
  unit
• Denault AY et al. Can J Anesth 2002 49 287-293
• Therapeutic impact of intra-operative
  transoesophageal echocardiography during
  non-cardiac surgery
• Hofer CK et al. Anaesthesia 2004 58 3-9
• Impact of intraoperative transoesophageal
  echocardiography during non-cardiac surgery
• Schulmeyer MCC et al. J Cardioth Vasc Anesth
  2006 20 768-771
• Use of transoesophageal echocardiography during
  cardiac arrest in patients undergoing elective
  non-cardiac surgery
• Lin T ey al. Br J Anaesth 2005 96 167-70

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What do they tell us?

• All show evidence that TOE can be used to guide /
  change therapy in the perioperative period
• Studies suggest TOE especially useful in the
  presence of Category I and less so in Category II
  indications
• TOE use can affect not only drug and fluid
  management but can also influence surgical
  management

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What do they tell us?

• TOE would appear to be particularly useful in
  management of patients with pre-op RWMA history
  of LVF, or Rt heart failure
• TOE is particularly useful in picking up new
  LV, RV or valvular dysfunction
• TOE may be useful in the non-cardiac surgery
  peri-arrest situation
• TOE may be used as a PAC substitute

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Why we should be cautious

• Level of evidence - all studies reported are
  essentially retrospective or prospective Cohort
  studies. PRCTs would give us a better level of
  evidence but clearly near impossible to perform
  in this study group
• There may be an inherent bias in retrospective
  review of the usefullness of TOE by TOE
  operators in certain studies.
• Mainly North American studies
• Inclusion criteria based mostly around old
  Category I and Category II indications really
  need more solid indications, criteria and level
  of risk for intervention.

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Why we should be cautious

• Some studies very protocol driven
• How does TOE compare to other monitoring
  modalities? There is a distinct lack of
  comparative studies.
• TOE may change perioperative management, but does
  it change long-term outcome?
• Although assumption that improved intra-operative
  management means better long-term outcomes
  probably valid, none of the non-cardiac studies
  actually demonstrate this

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Are there disadvantages to TOE?

• Expensive!
• TOE machine 100K
• Probes 20K
• Patient safety
• Consent issues
• Major morbidity
• Major complication rate 0-0.5
• Mortality 0.004
• Minor morbidity
• Common
• Who does it?
• Cardiologist
• Echocardiographer / Radiologist
• Anaesthetist

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Are there disadvantages to TOE?

• Training issues
• Intubation, image acquisition, handling
  interpretation
• Understanding of the implications of the
  perioperative setting
• Basic scanning vs full scanning
• Skills retention
• British Society of Echocardiography very clear as
  regards numbers, process and time course for
  accreditation
• How many do you need to perform to retain your
  skills?
• Is there any proven cost benefit?
• For monitoring not currently
• Lack of studies showing improvement in outcome

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TOE in Non-Cardiac Surgery

• When do I think we should consider using
  Perioperative TOE?

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My Indications for Perioperative TOE

• Diagnostic tool
• Not primarily. Diagnosis should be made prior to
  surgery
• Chance findings / diagnostic changes
• Monitoring tool
• Ultimate Cardiac monitor
• Subjective vs Objective - Look vs Measure
• use all available modes of Echo
• Monitor responses to therapy
• Other monitoring

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My Category I Indications for perioperative TOE

• Emergency use to determine the cause of an acute
  persistent and life-threatening haemodynamic
  disturbance

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• 69 year old male
• General surgery - splenectomy for myelofibrosis
• PMH incl previous MI (mild LV impairment) CVA
• Cardiac arrest day 4 on ward
• Resuscitated returned to theatre for
  laparoscopy / laparotomy - ? Intra-abdominal
  haemorrhage - negative
• Low BP despite inotropes
• High CVP ? PE
• On-table TOE requested

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• LV dilated with at least moderate impairment
• (FS 18 EF 37)
• New RWMAs
• Mild TR with mildly elevated PASP
• Elevated RAP
• Laminar flow in PA to bifurcation no evidence
  of PE in main PA proximal left PA or right PA
  3-4cm beyond bifurcation
• Pleural effusions small rim pericardial
  effusion

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• No PE
• Probable diagnosis cardiac arrest 2 to
  myocardial ischaemia

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My possible Category II Indications for
perioperative TOE

• Increased risk of haemodynamic instability
• Patients with significantly impaired cardiac
  function undergoing high-risk surgery
• A combination of both
• I cannot say what level of risk justifies TOE
  monitoring Risk Indexes may in future provide
  a starting point

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• Increased risk of haemodynamic instability
• severe cardiac disease
• aortic surgery
• extensive cancer surgery
• patients with HOCM
• risk of tumour or thrombus embolisation to heart
  with RVOT obstruction
• thoracic trauma

• Patients with significantly impaired cardiac
  function undergoing high-risk surgery
• severe cardiac failure
• severe LV dysfunction
• HOCM
• cardiomyopathy
• severe valvular disease

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• 28 year old female
• Gynaecological / General surgery
• Presented with abdominal pain / vomiting
• USS - ? Thrombus in IVC
• CT mass extending from iliac veins to IVC
• Diagnosis likely pelvic malignancy (? Uterine)
  extending up IVC
• PMH Myomectomy for uterine fibroid 3 yrs
  previously
• TOE requested to monitor thrombus / tumour in IVC
  and monitor for possible embolisation

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• Essentially normal heart
• Tumour / thrombus identified in IVC at hepatic
  level
• IVC not totally occluded turbulent flow around
  mass
• RA / Proximal PAs clear of abnormal tissue
  during / at end of procedure
• Hyperdynamic empty LV during removal of tumour
  from IVC with response to fluids.

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• Removal of IVC tumour / thrombus
• No obvious perioperative tumour / thrombus
• embolism to Rt heart

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• 65 year old female
• General urology ( Cardiac)
• Renal tumour with tumour / extension in IVC and
  RA
• TOE requested to monitor thrombus / tumour in IVC
  and monitor for possible embolisation

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• Dilated Rt heart with large variable echogenic
  mass extending out of IVC into RA and through TCV
  to RV
• Rt heart volume overload
• Good LV
• Tumour / thrombus mass broke free during handling
  mass now primarily in RV / RVOT prolapsing
  backwards into RA
• Post-CPB
• Rt heart failure severe RV dyskinesia
• Severe TR
• New LV RWMAs

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• IVC RA Tumour / thrombus embolism
• RVOT obstruction
• RV failure, then LV failure

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• 69 year old female with known HOCM
• Orthopaedics - Severe OA hip requiring THR
• PHM HOCM (gradient 84mmHg rest 110mmHg
  provoked) Hypertension COPD
• Initially turned down for surgery but pt keen to
  proceed and several Cardiological second opinions
  sought
• Proceeded to surgery with perioperative TOE
  monitoring

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• Uneventful rapid THR with blood loss lt500ml
• HOCM demonstrated anatomically and with CWD
• TOE used to guide management of apparent LV
  dysfunction
• ? Hypovolaemia
• ? Systolic anterior movement of Mitral valve /
  LVOT obstruction

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• HOCM
• Monitoring / minimisation of SAM / LVOT
  obstruction by appropriate fluid / drug
  management

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Conclusion

• Emergency use to determine the cause of an acute
  persistent and life-threatening haemodynamic
  disturbance during
• non-cardiac surgery
• There is good evidence to support
• use of emergent perioperative TOE

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Conclusion

• Increased risk of haemodynamic instability
• Patients with significantly impaired cardiac
  function undergoing high-risk surgery
• Jury is still out on the evidence available

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Conclusion

• More well-constructed directed studies are
  necessary to show whether perioperative TOE has a
  role for Category II indications in non-cardiac
  surgery
• We need to identify appropriate high or
  combination risk patient groups
• We need to demonstrate improved outcomes
• Whilst I cannot currently advocate routine use of
  perioperative TOE in non-Cardiac surgery, there
  will always be patients for whom TOE might
  provide that extra useful monitoring dimension
  and who might benefit from its use on a one-off
  case-by-case basis

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• My own personal feeling is that if we can address
  these issues then TOE-use in non-cardiac surgery
  might show benefit as it really is the ultimate
  cardiac monitor. However issues such as cost,
  equipment, trained personnel and skill retention
  will inevitably limit its use in the UK

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