Download Imaging Complications of Myocardial Infarction

Imaging Complications of Myocardial Infarction
Julianna M. Czum, MD
Imaging of Complications
of Myocardial Infarction
Disclosure
Consultant: M2S, Inc.
Julianna M. Czum, MD
WEDNESDAY
Assistant Professor of Radiology and Cardiology
Director, Division of Cardiothoracic Imaging, Department of Radiology
Nobody dies from myocardial
infarction.
People
P
l die
di from
f
complications
li ti
off
myocardial infarction.
Complications of Myocardial
Infarction include:
• Acute
• Cardiogenic shock
• Myocardial rupture
• Tachyarrhythmia
• Bradyarrhythmia
• AV block
• Early pericarditis
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• Chronic
• Progressive remodeling
• Left ventricular failure
• Aneurysm formation
• Mural thrombus
• Post MI syndrome
(Dressler syndrome)
Complications of Myocardial
Infarction include:
Acute
• Cardiogenic shock
• Myocardial rupture
• Tachyarrhythmia
• Bradyarrhythmia
• AV block
• Early pericarditis
Chronic
• Progressive remodeling
• Left ventricular failure
• Aneurysm formation
• Mural thrombus
• Post MI syndrome
(Dressler syndrome)
Objectives
1. To recognize the radiographic appearance of
circulatory support equipment in cardiogenic
shock
2. To discuss similarities and differences between
true and false ventricular aneurysms on MR
and CT
Cardiogenic Shock: CXR
Cardiogenic Shock
• Definition
• Cardiac dysfunction with inadequate compensatory
mechanisms (e.g. hypotension despite tachycardia)
• Results in insufficient cardiac output to perfuse
peripheral organs
• Occurs in 7Ͳ10% of acute MI
• Twice as common with STEMI than NonͲSTEMI
• Principal cause of inͲhospital death from acute MI
• Mortality can exceed 80%
Pulmonary edema
Present or absent
or asymmetric
Symmetric
y
y
Heart size: often normal
Check for support equipment
How an IABP works
Cardiogenic Shock: Support Equipment
• Ventricular assist devices (VADs)
• Percutaneous
• SurgicallyͲimplanted
Proper IABP tip position
• Balloon length: ~22-27.5 cm
• Optimal placement:
• Proximal descending
thoracic aorta (distal to L
subclavian A origin)
• Avoid p
placing
g too high:
g
• Aortic arch cerebral
branch vessel ostial
occlusion
• Avoid placing too low:
• Renal and mesenteric
artery ostial occlusion
• Ineffective
counterpulsation
•
•
•
www.ganfyd.org
Balloon inflates in diastole: јafterload:
• јcoronary blood flow, esp. L main coronary lesions
• јmyocardial perfusion
Deflates before systole: љLVEDP
“Assists” LV ejection: љafterload in systole; modest јCO
WEDNESDAY
• Counterpulsation:
• IntraͲaortic balloon pump (IABP)
Percutaneous LV Assist Devices
• Purpose:
• Augment cardiac output for peripheral organ
perfusion
• Variable CO augmentation, up to 8L/min
• Indications:
• Cardiogenic shock (IABP inadequate)
• Temporary support during complex percutaneous
coronary interventions
• Post CABG recovery/weaning
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Percutaneous VAD: Tip in LV Chamber
Percutaneous VAD: Tip in LV Chamber
Pump motor incorporated
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Percutaneous VAD cannula
Percutaneous VAD cannula
Transfemoral placement of venous (inflow)
and arterial (outlow) cannulas.
Pump motor location: external to patient
Surgically Implantable LV Assist Devices
• Implantable electromechanical cardiovascular support device
• Improves CO to maintain effective endͲorgan perfusion
• Uses:
• Bridge to transplant in patients with heart failure
• Destination therapy (transplantͲineligible)
• Bridge to myocardial recovery:
• Cardiogenic shock
• Highly selected nonischemic cardiomyopathy, e.g. viral
myocarditis, postpartum CM
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Agarwal P, Cascade P, Pagnani F.
AJR 2009; 193:W14-W24
Examples of implanted VADs
Visible components: Cannulas, valved conduits, pumps
Carr CM, Jacob J, Park SJ, et al.
Radiographics 2010; 30: 429-444.
Mortality in Major Shock Categories
100
80
87.3%
78.5%
59.2%
60
55.0%
55.1%
55.0%
6.9%
1.4%
Overall
mortality
60.1%
40
Incidence
20
2.8%
0
LV pump
failure
RV pump
failure
3.9%
Mortality
Ventricular Papillary m
Free wall
septal
rupture
rupture with
rupture
(severe MR) tamponade
Myocardial Rupture
• Rupture of nonͲfree wall myocardium:
• Septum
• Papillary
• Rupture of the free wall:
• Anterior, inferior, lateral
Adapted from:
Hochman JS, Buller CE, Sleeper LA, et al.
J Am Coll Cardiol 2000;36[Suppl A]:1063-1070.
Papillary Muscle Rupture
RUL Pulmonary Edema from Acute MR
WEDNESDAY
• Results in:
• Flail mitral valve leaflet
postͲinfarction mitral insufficiencyy
• Acute p
• Heart may not be enlarged, but pulmonary edema is
frequently visible
Selective retrograde blood flow from the mitral
valve directly into the RUL pulmonary veins
Free Wall Myocardial
Rupture Spectrum
1/16/11: Admission for STEMI
1. Incomplete free wall rupture:
a. Intramyocardial Hematoma
b Subepicardial Hematoma
b.
2. Complete free wall rupture:
a. Hemopericardium (w/ or w/o
tamponade)
b. Pseudoaneurysm formation
SSFP (systole)
DE
Shiozaki AA, Filho AA, Dallan LA,
et al. J Cardiovasc Magn Reson
2007;9:719-721.
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...but LV contour deformity present on CT
images for attenuation correction
3/18/11: After ICD placement
9/16/11: ReͲadmission for dyspnea
WEDNESDAY
Anterior wall myocardial infarction on
myocardial perfusion scintigraphy/SPECT
(3/10/11)
Complete Free Wall Myocardial
Rupture with LV Pseudoaneurysm
• Rupture of the LV free wall
• Usually catastrophic
• Occurs in 4% of patients after MI
• Pseudoaneurysm
• Non-fatal
N f t l rupture
t
• Contained by pericardium
• Risk of further expansion & rupture
• Treatment: aneurysectomy
• Common location: (postero)lateral LV wall
• sPericardial delayed enhancement
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LV Pseudoaneurysm: Cardiac CT example
LV True Aneurysm
True versus False Aneurysms
• All 3 layers of wall present
• Myocardium intact but thin
• Abnormal motion
• Akinetic (without movement)
y
bulging)
g g)
• Paradoxical motion ((systolic
• Location:
• Apex /apicoanterior wall common
• Posterior wall uncommon
• +/Ͳ calcification and/or luminal thrombus
• Rarely ruptures
Short-axis DE cardiac MR
Note the enhancement of
surrounding pericardium and
presence of intracavitary
thrombus
Konen E, Merchant N, Gutierrez C, et al.
Radiology 2005; 236:65-70.
Chest Radiograph: Abnormality
on either view?
Apical Infarct
Rounded apical contour
Laminar thombus
Bulky thombus
WEDNESDAY
Apical myocardial thinning
Myocardial calcification
Thrombus
Chest Radiograph:
Abnormal Posterior LV Contour
Posterobasal LV Aneurysm: True or Pseudo?
*
*
2Ͳchamber/vertical longͲaxis SSFP cardiac MR images
Arrow = mitral regurgitation
Yellow asterisk = anteromedial [papillary muscle
Red asterisk = posterolateral papillary muscle
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Posterobasal LV True Aneurysm
• ShortͲaxis SSFP
cardiac MR images
• Mid to basal left
ventricle
WEDNESDAY
Posterobasal LV True Aneurysm
Posterobasal LV
Aneurysm
• No dedicated cardiac CT
for this patient
• Abdominal CT (obtained
for unrelated reasons)
demonstrates bottom half
of heart, including the
known posterobasal
aneurysm
Posterobasal LV True Aneurysm
Mid to basal LV inferior wall: transmural
infarct with aneurysm formation
• 4Ͳchamber/horizontal longͲaxis SSFP cardiac MR images
• MidͲchamber to inferior left ventricle
• Arrow = mitral regurgitation
ShortͲaxis delayed enhancement cardiac MR images
Review
S/P LV aneurysm and MV repair
Cardiogenic shock
• Pulmonary edema may be
present or absent
• Selective RUL edema
suggests papillary
ill
muscle
l
rupture with acute MR
• Anticipate and recognize
circulatory support
equipment
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Apical to mid LV inferior wall:
subendocardial infarct
True vs false aneurysm
• Closely scrutinize postͲMI
chest radiographs for signs
• Thin wall of true aneurysm
may be difficult to distinguish
from pericardium overlying
pseudoaneurysm
• Typical locations suggestive
• Ratio of neck to body better
discriminator