Dysfunctional but viable myocardium Ischemic heart disease assessed by MRI and SPECT

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Dysfunctional but viable myocardiumIschemic
heart disease assessed by MRI and SPECT

• Martin Ugander, MD
• Department of Clinical Sciences, Lund
• Department of Clinical Physiology
• Lund University

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• Supervisor Håkan Arheden, MD, PhD
• Clinical Physiology, Lund
• Co-supervisor Peter Cain, MBBS, PhD
• Wesley Heart Clinic, Brisbane, AU
• Funding
• Swedish Research Council
• Swedish Heart Lung Foundation
• Faculty of Medicine at Lund University
• Region of Scania

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Aim

• To further elucidate the pathophysiology of
  dysfunctional but viable myocardium in patients
  with ischemic heart disease.

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Outline of Studies

• Study I - Method for quantitative MRI SPECT
• Study II - Wall thickening vs. Infarct
  transmurality
• Study III - LVEF vs. Infarct size
• Study IV - Time course of perfusion function
• after revascularization

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Study I

• Quantitative polar representation of left
  ventricular myocardial perfusion, function and
  viability using SPECT and cardiac magnetic
  resonance initial results
• Cain PA, Ugander M, Palmer J, Carlsson M, Heiberg
  E, Arheden H.
• Clin Physiol Funct Imag 2005 (25) 215-222

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Background

• Clinical management of CAD involves complex
  assessment of the extent and severity of changes
  in function, perfusion and viability.
• No adequate research tools for quantitative
  assessment exist.

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Aims

• To explore the feasibility of integrative
  quantitative representation of LV perfusion,
  function and viability in polar plots.
• To determine agreement between visual scoring and
  quantitative measures.

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Methods

• 10 patients scheduled for CABG
• rest/stress SPECT
• Cine and delayed enhancment CMR
• Quantification with in-house software
• Comparison with visual scoring using Kendalls
  coefficient of concordance (W)

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Methods
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Results
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Results
Kendalls W 1.0 (plt0.001) 0.85 (plt0.001)
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Conclusions

• Side-by-side quantitative polar representation of
  LV perfusion, function and viability is feasible
  and may aid in the complex assessment of these
  parameters.
• The agreement between quantitative measurement
  and visual scoring was very good.

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Study II

• Infarct transmurality and adjacent segmental
  function as determinants of wall thickening in
  revascularized chronic ischemic heart disease
• Ugander M, Cain PA, Perron A, Hedström E, Arheden
  H.
• Clin Physiol Funct Imag 2005 (25) 209-214

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Background

• Regional LV function in patients with IHD may be
  influenced by many factors.

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Aims

• To explore how regional wall thickening in
  patients with chronic IHD is affected by both
  infarct transmurality and the function of
  adjacent segments.
• To compare with results from healthy subjects.

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Methods

• 20 patients
• 6 months after revascularization
• Cine CMR
• Delayed enhancement CMR
• 20 matched controls
• Cine CMR

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Multivariate analysis of parameters contributing
to wall thickening

• t p
• Infarct transmurality -4.5 lt0.001
• Number dysf. adjacent seg. -22.9 lt0.001

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Conclusion

• The number of dysfunctional adjacent segments is
  a greater determinant than infarct transmurality
  on regional wall thickening.
• Infarction is difficult to assess by resting
  function alone.
• DE CMR is an important tool in this setting.

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Study III

• A maximum predicted left ventricular ejection
  fraction in relation to infarct size in patients
  with ischemic heart disease
• Ugander M, Ekmehag B, Arheden H.
• Submitted

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Background

• An understanding of the relationship between LVEF
  and infarct size is important when assessing the
  potential benefit of revascularization in
  patients with IHD.

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Aims

• To explore the relationship between LVEF and IS.
• To determine a maximum predicted LVEF for a given
  IS.

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Methods

• 297 patients clinically referred for viability
  assessment by CMR
• LVEF
• Infarct size ( LVM)

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Methods
A
LVEF ()
B
?
C
Infarct size (LVM)
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Patient characteristics (IHD)
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Distribution of infarctions
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Distribution of number of coronary artery vessel
territories
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Results
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Cine
Contrast
2ch
4ch
LVEF29
IS36
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Cine
Contrast
2ch
4ch
LVEF25
IS6
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Conclusions

• LVEF cannot be used to estimate IS.
• IS cannot be used to estimate LVEF.
• LVEF can be used to estimate a maximum predicted
  IS.
• IS can be used to estimate a maximum predicted
  LVEF.

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Study IV

• Influence of the presence of chronic
  non-transmural myocardial infarction on the time
  course of perfusion and functional recovery after
  revascularization.
• Ugander M, Cain PA, Johnsson P, Palmer J, Arheden
  H.
• Manuscript

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Background

• The time course of recovery of LV function and
  perfusion after revascularization is not fully
  understood.

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Aims

• To study the effect of presence of infarction on
  the time course of recovery of perfusion and
  function after elective revascularization.

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Methods

• 15 patients (inclusion ongoing)
• first time elective CABG (n13) or PCI (n2)
• Imaging
• rest/stress SPECT
• cine and delayed enhancement CMR
• Before revasc., 1 6 months after revasc.

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Patient characteristics

• 14 men, 1 woman
• mean age 68 years (range 52-84)
• 3VD n6
• 2VD n6
• 1VD n3
• LVEF 49 ? 10

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Distribution of infarct transmuralities
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Conclusions

• Dysfunctional segments without infarction
  improved both perfusion and function at 1 month.
• Segments with infarction showed improved
  perfusion at 1 month and improved function at 6
  months.
• This may reflect more severe ischemic burden in
  segments with infarction.

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Summary

• Study I - Method for quantitative MRI SPECT
• Study II - Wall thickening vs Infarct
  transmurality
• Study III - LVEF vs Infarct size
• Study IV - Time course of perfusion function
• after CABG

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Conclusion

• It is important to perform quantitative
  assessment of function,perfusion and viability in
  combination when studying the pathophysiology of
  dysfunctional but viable myocardium in IHD.

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www.med.lu.se/cmr
Henrik Engblom, MD, PhD-student
Bo Hedén, MD PhD
Einar Heiberg ,PhD
Håkan Arheden, MD PhD
Ann-Helen Arvidsson, tech
Henrik Mosén, MD, PhD
Christel Carlander, tech
Karin Markenroth, PhD
Marcus Carlsson, MD, PhD-student
Erik Bergvall, MSc, PhD-student
Martin Ugander, MD, PhD-student
Erik Hedström, PhD
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The ischemic cascade
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Mahrholdt et al 2005 Eur Heart J
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