Download Left Ventricle: Ischemia and Function Small Group Discussion

Left Ventricle: Ischemia and Function
Small Group Discussion
Mark A. Taylor, MD
Allegheny Health Network
Temple University
Pittsburgh, PA
John Fox, MD
Brigham and Women’s Hospital
Boston, MA
Learning Objectives:
1. Review the normal LV anatomy and function using 2D ultrasound and
Doppler.
2. Describe systolic LV function using 2D ultrasound and Doppler under
conditions of alterations in loading conditions, dyssynchrony and pacing
effects.
3. Describe how to calculate different echocardiographic measures of left
ventricular volume and function
4. Recognize the echocardiographic manifestations of regional LV systolic
dysfunction.
Case 1: A 64 yo presents for elective coronary artery bypass graft surgery for severe
three-vessel coronary artery disease. Planned surgical approach is a LIMA to the LAD
and SVGs to the RCA and CX distribution.
Question:
What standard views will you obtain to evaluate LV global
and segmental function?
Key point: To evaluate LV global and segmental function, 6 standard views of the heart
are obtained and include:
ME 4-chamber
ME 2-chamber
ME LAX
TG Midpapillary SAX
TG Basal SAX
TG Apical SAX
Question:
Describe how you will systematically evaluate LV global
systolic function?
Key point:
Evaluate all 6 images and assess overall contractility qualitatively and
quantitatively. Overall wall motion and systolic thickening of all 16 segments should be
included in this global measure. Qualitative interpretation should be followed by
quantitative measures. Ejection fraction represents the difference between EDVESV/EDV x 100 or SV/EDV x 100. Normal systolic ejection fraction is 55-70%.
Measurements below 52% in males and 54% in females are abnormal and lower values
are consistent with evidence of heart failure or cardiomyopathy. An EF between 40 and
55% indicates myocardial damage but may not represent heart failure. Heart failure is
classified as either:
Heart failure with preserved ejection fraction (HFPEF)
-diastolic heart failure
Heart failure with reduced ejection fraction (HFREF)
-systolic heart failure.
Question:
Describe how you will systematically evaluate the LV segmental function?
Key point:
Evaluate all 6 imaging views for the left ventricle and on each image the
corresponding 6 or 4 segments at each level of the ventricle (apex, mid
pap, and base). To each segment assess regional function, inward radial
motion, and systolic wall thickening.
Regional Function
Normal or
hyperkinesis
Hypokinesis
Akinesis
Dyskinesis
Grade
1
Inward Radial Motion
> 30%
Systolic Wall Thickening
Marked
2
3
4
10% to 29%
<10%
Paradoxical systolic
motion
Reduced
Negligible
Systolic Thinning
Aneurysmal or Grade 5 is no longer a recommended wall motion grade and aneurismal
segments can be either akinetic or dyskinetic.
Case 2: An 86 year old patient presents for a coronary artery bypass graft. The
surgeon asks you to assess global and regional function. You see the referring
cardiologist and the cardiologist ask you what the patients wall motion score index is for
this patient. Your assessment is as follows:
Level
Segment(s)
Basal (6)
Anterior
Anteroseptum
Inferoseptum
Inferior
Inferolateral
Anterolateral
Anterior
Anteroseptum
Inferoseptum
Inferior
Inferolateral
Anterolateral
Anterior
Septal
Inferior
Lateral
Apical cap
MidPapillary (6)
Apex (4 or 5)
Regional
Function
Grade
2
2
1
1
1
2
3
3
2
1
1
4
4
4
4
4
-
Key Point:
Wall motion score index is a semi-quantitative analysis of regional
function and equals sum of all scores divided by the number of segments visualized. In
the example above, WMSI = 39/16 which equates to 2.44. A normal ventricle with no
segmental wall motion abnormalities will have a WMSI of 1 and increasing values of
WMSI towards 4 indicates more significant regional wall motion abnormalities.
Case 3:
You are called urgently into small bowel resection for an elderly female
suffering from a long-standing small bowel obstruction. She presented to the OR
dehydrated and anemic. After induction, she becomes hypotensive and despite 2 liters
of IV fluid and two units of packed red blood cells remains hypotensive and is on a
neosynephrine infusion. You are asked to perform an urgent transesophageal
echocardiogram to assess for left ventricular volume and function.
Question:
How do you assess left ventricular preload by transesopheageal
echocardiography?
Question:
How do changes in contractility and SVR affect TEE findings?
Key Points: Echocardiography can be utilized to qualitatively and semiqualitatively
assess preload as the volume at the end of diastole. Left ventricular end diastolic area
(EDA) may serve as a surrogate for preload. Graded hypovolemia, in both pediatric and
adult patients demonstrate changes in LVEDA (TG mid pap SAX), which mirror changes
in volume status.
EDA index (cm2/m2) = LVEDA/BMI
An EDA indexed to BSA less than 5.5 cm2/m2 defines hypovolemia. A decrease left
ventricular end systolic area (ESA) or end-systolic cavity obliteration can suggest
hypovolemia but has low specificity for predicting a decrease in preload. In addition to
hypovolemia, an increase in ejection fraction or a decrease in systemic vascular
resistance can lead to end systolic cavity obliteration.
Question
In this same hypovolemic patient, how do you calculate the following
quantitative parameters of LV function?
Fractional Shortening
Fractional Area Change
LVOT Stroke Volume and cardiac output
Ejection Fraction?
Key Points: Transesophageal echocardiography can be used to calculate the
following quantitative parameters of LV function:
Fractional Shortening: % FS = [(LVEDD-LVESD) / LVEDD] x 100
Based upon mmode echocardiography and ventricular diameters
Fractional area change: %FAC = [(LVEDA-LVESA)/LVEDA] x 100
Based upon 2D imaging of TG mid papillary area measurement
LVOT Stroke Volume and cardiac output
SV = Area x VTI where area is the area of the LVOT or the aortic valve and VTI
is the velocity time integral of blood passing through the respective area being
measured.
CO = SV x HR
Ejection Fraction EF = (EDV-ESV/EDV) x 100
Volumes obtained by Simpson’s Method of disc measurements from the ME 4chamber and ME 2-chamber views. One may use 3D TEE to obtain accurate
volumes by 3D analysis.
Case 4:
You have just completed an Aortic Valve Replacement (AVR) and the
patient is requiring pacing to separate from cardiopulmonary bypass due to conduction
block following surgery.
Question:
function?
Question:
How does ventricular pacing with epicardial wires affect left ventricular
How do other conduction abnormalities affect left ventricular function?
Key Points: Ventricular pacing and intraventricular conduction delays can create
regional wall motion abnormalities including septal dyskinesis. In the immediate post
bypass period, echocardiographic examination of regional wall motion can be evaluated
with patients paced and unpaced (if appropriate) to determine the effects of pacing.
Case 5:
You are contemplating upgrading your TEE service line to all 3D
equipment and are asked to write a proposal outlining the clinical benefits for your
chairman.
Question:
How will 3D TEE change your approach to the qualitative evaluation of LV
systolic function?
Question:
How will 3D TEE change your approach to the quantitative evaluation of
global systolic function including ventricular volumes and ejection fraction?
Question:
How will 3D TEE change your approach to the qualitative and quantitative
evaluation of regional left ventricular function?
Key Points: Advantages of 3D ventricular volume measurements over 2D techniques
include avoidance of geometric assumptions. Complete systolic and diastolic volumes
can be obtained and then calculation of volume-based functions including stoke volume
and ejection fraction can be determined. Global left ventricular volumes, EF
measurements and function using real-time 3D TEE is quick, more accurate and
reproducible than with 2D echocardiography and correlate highly with cardiac MRI.
Interobserver variability in volume determination is less with 3D echocardiography in
comparison to 2D. 3D echocardiography has been demonstrated to be useful in the
assessment of global and regional left ventricular wall motion and quantification of
systolic dyssynchrony. A systolic dyssynchrony index (SDI) may be calculated which is
the standard deviation of regional ejection times. A recent study by Meris, et al,
investigating intraoperative 3D TEE and its role in quantification of LV global function,
demonstrated that image acquisition time, and reproducibility was not statistically
different than conventional 2D imaging. 3D TEE quantification though was associated
with larger volumes and longer analysis times but these larger volumes did not affect the
overall LV function classification models. Based upon the closer limits of agreement with
MRI and better reproducibility the 2D echocardiography, 3D echocardiography can be
recommended for standard utilization to determine LV volumes and ejection fraction. As
stated by the EAE/ASE consensus statement regarding 3D echocardiography, “3D TTE
and TEE assessment of LV volumes and ejection fraction is recommended over the use
of 2D echocardiography.”
Further Reading:
1. Reeves ST, Finley AC, Skubas NJ, et al. Basic perioperative
transesophageal echocardiograpy examination: A consensus statement of
the American Society of Echocardiography and the Society of Cardiovascular
Anesthesiologist. Anes Analg 2013;117:543-558.
2. Hahn RT, Abraham T, Adams MS, et al. Guidelines for performing a
comprehensive transesophageal echocardiographic examination:
Recommendations from the American Society of Echocardiography and the
Society of Cardiovascular Anesthesiologists. Anes Analg 2014;118:21-68.
(also in J Am Soc Echocardiogr 2013;26:921-964.)
3. Lang RM, Bierig M, Devereux RB, et al. Recommendations for chamber
quantification: A report from the American Society of Echocardiography’s
Guidelines and Standards Committee and the Chamber Quantification
Writing Group, developed in conjuction with the European Association of
Echocardiography, a branch of the European Society of Cardiology. J Am
Soc Echocardiogr 2005;17:1086-1119.
4. Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for cardiac
chamber quantification by echocardiography in adults: An update from the
American Society of Echocardiography and the European Association of
Cardiovascular Imaging. J Am Soc Echocardiogr 2015;28:1-39.
5. Meris A, Satambrogio L, Casso G, et al. Intraoperative three-dimensional
versus two-dimensional echocardiography for left ventricular assessment.
Anes Analg 2014;118:711-720.
6. Lang RM, Badano LP, Tsang W, et al. EAE/ASE recommendations for image
acquistion and display using three-dimensional echocardiography. J Am Soc
Echocardiogr 2012;25:3-46.