Coverage Policy Manual
Policy #: 2019001
Category: Radiology
Initiated: April 2019
Last Review: April 2022
  Myocardial Strain Imaging

Description:
The term ‘myocardial strain’ is used to describe the magnitude of shortening, thickening and lengthening of the myocardium through the cardiac cycle. The most frequent measure of myocardial strain is the deformation of the left ventricle (LV) in the long axis, termed global longitudinal strain (GLS).  During systole, ventricular myocardial fibers shorten with movement from the base to the apex. GLS is used  as a measure of global LV function, and provides a quantitative myocardial deformation analysis of each LV segment. Myocardial strain imaging is intended to detect subclinical changes in left ventricle function in patients with a preserved LV ejection fraction, allowing for early detection of systolic dysfunction. Since strain imaging can identify LV dysfunction earlier than standard methods, this raises the possibility of  heart failure prophylaxis and primary prevention before the patient develops symptoms and irreversible myocardial dysfunction. Potential applications of speckle-tracking echocardiography (STE) are coronary artery disease, ischemic cardiomyopathy, valvular heart disease, dilated cardiomyopathy, hypertrophic cardiomyopathies, stress cardiomyopathy, and chemotherapy-related cardiotoxicity.
 
Myocardial strain can be measured by either tissue Doppler imaging or by speckle-tracking echocardiography (STE). Tissue Doppler strain imaging has been in use since the 1990's but has limitations that include angle dependency and significant noise. Smiseth et al, reported that the most widely used method of measuring myocardial strain at the present time is STE (Smiseth, 2016). In STE, natural acoustic markers generated by the interaction between the ultrasound beam and myocardial fibers form interference patterns (speckles). These markers are stable, and STE analyzes the spatial dislocation (tracking) of each point (speckle) on routine 2-dimensional sonograms. Echocardiograms are processed using specific acoustic-tracking software on dedicated work stations, with offline semiautomated analysis of myocardial strain. The 2-dimentional displacement is identified by a search with image processing algorithms for similar patterns across two frames. When tracked frame-to-frame, the spatiotemporal displacement of the speckles provides information about myocardial deformation across the cardiac cycle. GLS provides a quantitative analysis of each LV segment, which is expressed as a percentage. In addition to GLS, STE allows evaluation of LV rotational and torsional dynamics.
 
Regulatory Status
A number of image analysis systems have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. For example, the Echolnsight software system (Epsilon Imaging) "enables the production and visualization of 2D tissue motion measurements (including tissue velocities, strains, strain rates) and cardiac structural measurement information derived from tracking speckle in tissue regions visualized in any Bmode (including harmonic) imagery loops as captured by most commercial ultrasound systems" ( K110447). The FDA determined that this device was substantially equivalent to existing devices (eg  syngo US Workplace, Siemens, K091286) for analysis of ultrasound imaging of the human heart.
 
Coding
 
There is no specific CPT code for this procedure. The following CPT code might be used:
 
0399T Myocardial strain imaging (quantitative assessment of myocardial mechanics using image-based analysis of local myocardial dynamics) (List separately in addition to code for primary procedure).

Policy/
Coverage:
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
Myocardial strain imaging does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.
 
For members with contracts without primary coverage criteria, myocardial strain imaging is considered investigational. Investigational services are specific contract exclusions in most member benefit certificates of coverage.

Rationale:
Myocardial Strain Imaging to Detect Cardiotoxicity
 
The purpose of MSI in patients who have an indication for a transthoracic echocardiogram is to inform a decision whether to modify monitoring and/or treatment before the patient develops symptoms and irreversible myocardial dysfunction.
 
The American College of Cardiology, American association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Hearth Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons (2019) published appropriate use criteria for multimodality imaging in the assessment of cardiac structure and function in nonvalvular heart disease (Doherty, 2019). The American College of Cardiology et al considered strain imaging by speckle or tissue Doppler appropriate for the following indications:
    • Initial evaluation prior to exposure to medications/radiation that could result in cardiotoxicity/heart failure,
    • Re-evaluation (one year) in a patient previously or currently undergoing therapy with potentially cardiotoxic agents
    • Periodic re-evaluation in a patient undergoing therapy with cardiotoxic agents with worsening symptoms, and
    • Evaluation of suspected hypertrophic cardiomyopathy.
 
The most developed evidence base on MSI is for cardiotoxicity, therefore, this evidence review will focus on clinical outcomes from use of strain imaging by speckle-tracking echocardiography (STE) or tissue Doppler imaging for the initial assessment and follow-up for cardiotoxicity.
 
Cardiovascular complications of cancer treatment can be either acute or chronic (early or delayed) and include heart failure, myocardial ischemia or infarction, hypertention, thromboembolism, and arrhythmias. Presymptomatic detection of cardiotoxicity may allow modification of cancer therapy combinations or use of cardioprotective agents.
 
For patients who are undergoing chemotherapy, current recommendations are to measure ejection fraction (EF) prior to chemotherapy, at completion of therapy, and six months later. It has been proposed that the measurement of myocardial strain in addition to EF will be helpful in cases when EF is in the lower normal range, and in these cases, the finding of subnormal strain should result in closer monitoring of cardiac function, modification of cancer therapy, and/or use of cardioprotective agents.
 
The most frequent measure of myocardial strain imaging is global longitudinal strain, which averages values over the length of the myocardial wall. Positive values indicate lengthening, thickening, or clockwise rotation. Greater deformation is indicated by lower strain values. Cardiac strain in a healthy individual is a generally around 20%, indicated in echocardiography by a negative number (-20). In a meta-analysis of 24 studies (2597 healthy volunteers), Yingchoncharoen et al, reported that global longitudinal strain varied from -15.9% to -22.1% (mean -19.7%,  95% confidence interval -18.9% to -20.4%) (Yingchoncharoen, 2013). Shortening of more than 20% is generally considered normal.
 
Thavendiranathan et al conducted a systematic review of myocardial strain imaging for the early detection of cardiotoxicity in patients during and after cancer chemotherapy (Thavendiranathan, 2014). Searches were conducted through November 2013. The reviewers included prospective or retrospective studies of at least ten patients that used echocardiographic-based myocardial deformation parameters as the primary method to detect cardiotoxicity. Studies had to provide data on changes in deformation parameters and LVEF during therapy. The authors focused the review on three clinical scenarios: 1) detection of early myocardial changes; 2) prediction of subsequent cardiotoxicity; and 3) detection of late consequences of therapy (>1 year posttreatment).
 
Detection of early myocardial changes: Thirteen single-center cohort studies (n=384) provided information on MSI parameters to detect early myocardial changes in patients treated with anthracycline-containing regimens. The earlier studies (n=7) used tissue Doppler imaging while more recent studies (n=6) used STE.  There was heterogeneity regarding patient age, types of cancer, strain techniques, and timing of follow-up but all of the studies found that changes in myocardial deformation occurred earlier than changes in LVEF. In addition, reductions in myocardial deformation occurred at doses lower than those historically considered cardiotoxic.
 
Prognosis for early cardiotoxicity: Eight observational studies (n=452) included in the systematic review evaluated the prognostic value of MSI for subsequent cardiotoxicity (LVEF reduction or the development of heart failure). The studies differed in duration of follow-up (6 months, 12 to 15 months), treatment regimens, and other factors but used a similar definition of cardiotoxicity. The researchers found that an early fall in global longitudinal strain  of 10% to 15% using STE predicted subsequent cardiotoxicity.
 
Prognosis for late cardiotoxicity: Nine case-control studies (n=436) were identified that compared findings in patients to controls. All of the studies used various myocardial deformation parameters to detect late subclinical cardiac injury but none provided data on subsequent cardiac events.
 
The authors identified the following areas for future research:
    • Determination of whether strain-based approaches could be reliably implemented in multiple centers, including nonacademic settings,
    • Study in  larger multicenter studies and in cancers other than breast cancer
    • Need to determine the optimum sampling (single or multiple)
    • Comparison with a traditional LVEF-based approach
    • Understanding the long-term effect of strain changes that occur during therapy
    • The use of vendor-neutral methods to measure strain
    • The prognostic significance of strain abnormalities in survivors of cancer and those receiving radiation therapy
    • Whether intervention would change the natural course of the cardiac disease.
 
No direct evidence of the clinical utility of MSI is currently available. The Strain Surveillance of Chemotherapy for Improving Cardiovascular Outcomes trial, currently in progress, will be the first randomized controlled trial of MSI and will provide evidence to inform guidelines regarding the place of MSI for surveillance for cardiotoxicity related to cancer chemotherapy. Preliminary descriptive results on the first 86 patients have been published (Negishi, 2018).
 
Practice Guidelines and Position Statements
 
American College of Cardiology
The ACC, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Hearth Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons published appropriate use criteria for multimodality imaging in the assessment of cardiac structure and function in nonvalvular heart disease (Doherty, 2019).
 
Using a modified Delphi approach, the panel rated indications as “appropriate”, “may be appropriate”, and “not appropriate” (Hendel, 2018). The specific studies that formed the basis of the ACC guidelines are not cited, however, they note that they used ACC/American Heart Association clinical practice guidelines whenever possible.
 
Of 81 indications considered for strain rate imaging, the panel rated only 4 as “appropriate”. Three of the four concerned evaluation (initial or follow-up) in patients prior to and following exposure to potentially cardiotoxic agents. The other indication was follow-up testing to clarify initial diagnostic testing for patients with suspected hypertrophic cardiomyopathy. The guidelines did not separate out imaging with speckle tracking and tissue Doppler, and did not make recommendations related to the comparative effectiveness of these imaging modalities.
 
The panel rated 14 other indications “may be appropriate”. According to the panel, interventions in this category should be performed depending on individual clinical patient circumstances and patient and provider preferences, including shared decision making (Hendel, 2018).
 
American Society of Clinical Oncology
The American Society of Clinical Oncology(2017) noted that measurement of strain has been demonstrated to have some diagnostic and prognostic use in patients with cancer receiving cardiotoxic therapies but that there have been no studies demonstrating that early intervention based on changes in strain alone can result in changes in risk and improved outcomes (Armenian, 2016). The American Society of Clinical Oncology also notes that screening for asymptomatic cardiac dysfunction using advanced imaging could lead to added distress in cancer survivors.
 
Ongoing and Unpublished Clinical Trials
 
Some currently ongoing and trials that might influence this review are listed below.
 
SUCCOUR is a randomized controlled trial that will evaluate clinical outcomes for patients who are monitored by myocardial strain imaging or conventional imaging. Patients with an abnormal test result will receive improved blood pressure and glucose control. Protective therapy with ACE inhibitors and beta blockers will be titrated to target dose.  This will be the first trial to assess clinical outcomes based on myocardial strain imaging compared to conventional imaging (limited to evaluation of ejection fraction and valve disease). The SUCCOUR trial will provide evidence to inform guidelines regarding the place of global longitudinal strain for surveillance for cardiotoxicity (Negishi, 2018).
 
NCT03543228 MyoStrain CMR for the Detection of Cardiotoxicity (Prefect) Planned Enrollment: 50 Completion Date: Jun 2019
 
NCT03825224 Evaluation of MyoStrain in Clinical Practice Planned Enrollment: 100 Completion Date: Feb 2020
 
NCT02286908 Global Strain and Mechanical Dispersion May Predict Death and Ventricular Arrhythmias Better Than Ejection Fraction Planned Enrollment: 3100 Completion Date: Dec 2021
 
NCT03297346 Early Detection of Cardiovascular Changes After Radiotherapy for Breast Cancer (EARLY-HEART) Planned Enrollment: 250 Completion Date: May 2021
 
NCT02608567 Prognostic Impact of Myocardial Longitudinal Strain in Asymptomatic Aortic Stenosis: a Meta-Analysis Planned Enrollment: 1000 Completion Date: Dec 2017
 
2020 Update
A literature search was conducted through March 2020.  There was no new information identified that would prompt a change in the coverage statement.  The key identified literature is summarized below.
 
American College of Cardiology
The ACC, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Hearth Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons published appropriate use criteria for multimodality imaging in the assessment of cardiac structure and function in nonvalvular heart disease (ACC, 2019).
 
2021 Update
Annual policy review completed with a literature search using the MEDLINE database through March 2021. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Strain is a dimensionless measure of tissue deformation (L – L0)/L0, where L is final length and L0 the original length; positive values indicate lengthening, and negative values indicate shortening (Trivedi, 2019).
 
2022 Update
Annual policy review completed with a literature search using the MEDLINE database through March 2022. No new literature was identified that would prompt a change in the coverage statement.

CPT/HCPCS:
0399TMyocardial strain imaging (quantitative assessment of myocardial mechanics using image based analysis of local myocardial dynamics) (List separately in addition to code for primary procedure)
93356Myocardial strain imaging using speckle tracking derived assessment of myocardial mechanics (List separately in addition to codes for echocardiography imaging)

References: Armenian, SS, Lacchetti, CC, Lenihan, DD.(2016) Prevention and Monitoring of Cardiac Dysfunction in Survivors of Adult Cancers: American Society of Clinical Oncology Clinical Practice Guideline Summary. J Oncol Pract, 2016 Dec 7;13(4). PMID 27922796.

Doherty, JJ, Kort, SS, Mehran, RR, et al.(2019) ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2019 Appropriate Use Criteria for Multimodality Imaging in the Assessment of Cardiac Structure and Function in Nonvalvular Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons. J Am Soc Echocardiogr, 2019 Feb 13. PMID 30744922.

Doherty, JJ, Kort, SS, Mehran, RR, Schoenhagen, PP(2019) ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2019 Appropriate Use Criteria for Multimodality Imaging in the Assessment of Cardiac Structure and Function in Nonvalvular Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons. J Am Soc Echocardiogr, 2019 Feb 13. PMID 30744922

Hendel, RR, Lindsay, BB, Allen, JJ, Brindis, RR, et al.(2018) ACC Appropriate Use Criteria Methodology: 2018 Update: A Report of the American College of Cardiology Appropriate Use Criteria Task Force. J. Am. Coll. Cardiol., 2018 Feb 24;71(8). PMID 29471942.

Negishi, TT, Thavendiranathan, PP, Negishi, KK, Marwick, TT, et al.(2018) Rationale and Design of the Strain Surveillance of Chemotherapy for Improving Cardiovascular Outcomes: The SUCCOUR Trial. JACC Cardiovasc Imaging, 2018 Jun 18;11(8). PMID 29909105.

Smiseth, OO, Torp, HH, Opdahl, AA, et al.(2015) Myocardial strain imaging: how useful is it in clinical decision making? Eur. Heart J., 2015 Oct 29;37(15). PMID 26508168.

Thavendiranathan, PP, Poulin, FF, Lim, KK, Plana, JJ, et al.(2014) Use of myocardial strain imaging by echocardiography for the early detection of cardiotoxicity in patients during and after cancer chemotherapy: a systematic review. J. Am. Coll. Cardiol., 2014 Apr 8;63(25 Pt A). PMID 24703918.

Trivedi SJ, Altman M, Stanton T, et al.(2019) Echocardiographic Strain in Clinical Practice. Heart Lung Circ. 2019 Sep;28(9). PMID 31064715

Yingchoncharoen, TT, Agarwal, SS, Popović, ZZ, Marwick, TT. Normal ranges of left ventricular strain: a meta-analysis.(2012) Normal ranges of left ventricular strain: a meta-analysis. J Am Soc Echocardiogr, 2012 Dec 12;26(2). PMID 23218891.


Group specific policy will supersede this policy when applicable. This policy does not apply to the Wal-Mart Associates Group Health Plan participants or to the Tyson Group Health Plan participants.
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