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Medical Policy

Policy Num.     06.001.022
Policy Name:   Intravascular Ultrasound Imaging of Coronary Arteries
Policy ID          [06.001.022]  [Ar / B / M+ / P-]  [6.01.04]

Last Review:    August 31, 2023
Next Review:    Policy Archived
Issue:                2:2023

ARCHIVED

Related Policies: None

Intravascular Ultrasound Imaging of Coronary Arteries
 

summary

Transcatheter intravascular ultrasound (IVUS) imaging is a technique in which a miniaturized ultrasound transducer, mounted on the tip of a catheter, is inserted directly into an artery or vein to produce either 2- dimensional tomographic images or 3-dimensional computer-assisted reconstructions of planar IVUS images. As applied to intracoronary imaging, intravascular ultrasound is used as an adjunct to angioplasty, atherectomy, or placement of a stent. Intracoronary Doppler ultrasound, which provides a functional measure of flow across a coronary lesion, is addressed separately in Policy No. 6.01.19.

Acquiring an ultrasound image of the coronary arteries through a catheter is a technique where a miniaturized transducer is placed at the tip of the catheter and is inserted directly into an artery or vein to produce tomographic images two-dimensional or three-dimensional images reconstructed with the assistance of a computer. This methodology applied to ultrasound is used as a complement to the angioplasty, atherectomies, and in the placement of stents. This methodology is known such as IVUS and specifically assesses the shape of the artery wall.

Visual evaluation of a coronary stenosis, as demonstrated by a angiography, has generally been the basis  for decision-making where consideration is given to cardiac revascularization procedures, either PTCA, atherectomies or CABG. This visual assessment of strictures is not objective and the clinical  significance of lesions Intermediate (40-70% obstruction) is often unknown. The ultrasound Intravascular Doppler provides a functional measure of blood flow through a coronary lesion. The coronary flow  reserve (”coronary reserve flow”) or CRF has emerged as an additional evaluation to assess the clinical significance of strictures of the coronary arteries. The CRF is defined as the ratio between the low coronary flow Maximum arterial dilation and coronary flow under resting conditions. A CRF normal is any value over 3. To perform this evaluation, the transducer is progresses through the stenosis and determines the maximum blood velocity in that point. Then, vasodilatation is induced by injecting intracoronary adenosine and re-measures the velocity of blood flow.

Policy Statement

The use of IVUS in transcatheter revascularization therapy of coronary artery disease may be considered medically necessary as a technique of guiding transcatheter revascularization.

Intracoronary ultrasonography is considered for payment, to determine the significance of an intermediate stenosis (40% to 70% obstruction) or to determine the lesion to be revascularized in case of multiple lesions. The great advantage of intracoronary ultrasound is that the clinical significance of stenosis intermedia can be assessed at the time of angiography and treatment not postponed (PTCA or CABG) until performing  cardiac function tests.

 The IVUS is considered for payment under the following conditions:

• When through a pre-angiogram functional test (eg perfusion test cardiac) it is not possible to establish the diagnosis. The use of ultrasound will be required intravascular to determine the degree of obstruction.
• When a pre-angiogram functional test is positive for a lesion significant, but that at the time of  angiography lesions are found multiple. In this case, intravascular ultrasound would be used to determine which lesion or lesions would proceed to revascularize.

The routine use of intracoronary ultrasound and the concomitant use of Functional tests of the heart*, be  they pre or post angiogram will not be considered for payment. *Cardiac perfusion test.

Policy Guidelines

The American College of Cardiology Guidelines for Coronary Intervention (PCI), suggests that "the weight  of evidence/opinion is in favor of its value" in the following indications: 

• Evaluation of the position and determination of the minimum diameter of the stent lumen for  placement of a stent.
• Determination of the stent restenosis mechanism, helps enable selection of the appropriate  therapy.
• Assessment of coronary obstruction in a patient that has been difficult to assess for angiography suspicion of stricture obstruction.
• Evaluation of areas suboptimally visualized by angiograph.
• Diagnosis and management of coronary disease in heart transplant patients heart.
• Establish the presence and distribution of calcium in the coronary arteries.
• Determine the location and circumferential distribution of atheromatous plaques in those patients who are going to perform an atherectomy.

The following are the recommendations made regarding the use of IVUS for PCI, according to guidelines from the American College of Cardiology (ACC).[3]

CLASS IIa:

1. IVUS is a reasonable option to assess angiographically indeterminant left main CAD (Level of Evidence: B)
2. IVUS and coronary angiography are within reason 4 to 6 weeks and 1-year post cardiac transplantation to rule out donor CAD, detect rapidly progressive cardiac allograft vasculopathy, and provide prognostic information  (Level of Evidence: B)
3. IVUS is a reasonable option to determine the mechanism of stent restenosis (Level of Evidence: C)

CLASS IIb:

1. IVUS may be reasonable in assessing non–left main coronary arteries possessing angiographically intermediate coronary stenoses (i.e., 50% to 70% diameter stenosis)  (Level of Evidence: B)
2. IVUS may be considered for the guidance of coronary stent implantation, especially in cases of left main coronary artery (LMCA) stenting (Level of Evidence: B)
3. IVUS may be reasonable for the determination of the mechanism of stent thrombosis   (Level of Evidence: C)

CLASS III:

1. IVUS for routine lesion assessment is not a recommendation if revascularization with PCI or CABG is not being contemplated (Level of Evidence: C)

Benefit Application

BlueCard/National Account Issues

IVUS may be used prior to an intervention to determine the appropriate type of revascularization procedure, during the intervention, for example, to determine the appropriate placement of a stent, and  finally after the intervention to determine the acute procedural success. However, it is anticipated that only a single reimbursement for IVUS would be warranted.

Benefits are determined by the group contract, member benefit booklet, and/or individual subscriber certificate in effect at the time services were rendered.  Benefit products or negotiated coverages may have all or some of the services discussed in this medical policy excluded from their coverage.

Background

Angiography is limited in determining the anatomic severity of coronary artery stenoses because it represents only a projectional image of the vessel lumen without providing any information concerning vascular wall architecture.  Catheter-based intravascular ultrasound (IVUS) has been developed in the last few years to provide this unique perspective for viewing vascular disease and the effects of intervention.  As a complement to the information provided by coronary angiography, it has the unique ability to study vessel wall morphology in vivo, accurately displaying the details of vessel structure and tissue characterization by providing such critical information as the presence and degree of calcified plaque, quantifying luminal dimensions, and characterizing the composition of stenotic lesions into soft plaque, hard plaque, calcification, and type of thrombus.

Although these devices have only been available for a relatively short time, an array of studies demonstrating numerous diagnostic and therapeutic applications in interventional cardiology have been reported.  The maturity of the technology is such that IVUS currently has a place as a clinical decision-making tool in patients with symptoms and intermediate lesions, as a provisional study to assess left main stem disease suspected but not disclosed by coronary angiography, and as a method for both guidance of endoluminal devices and immediate assessment of the results of therapeutic techniques, including balloon angioplasty, atherectomy, and intravascular stent deployment.

Diagnosing Functionally Significant Non-Left Main Coronary Artery Disease and Determining Whether or Not To Proceed With the PCI of Intermediate Non-Left Main Coronary Artery Stenosis

Jang and colleagues (2016) noted that IVUS-guided PCI frequently results in unnecessary stenting due to the low positive predictive value of IVUS-derived minimal lumen area (MLA) for identification of functionally significant coronary stenosis.  In a meat-analysis, these investigators  appraised the diagnostic accuracy of IVUS-derived MLA compared with the fractional flow reserve (FFR) to assess intermediate coronary stenosis.  These investigators searched Medline and Cochrane databases for studies using IVUS and FFR methods to establish the best MLA cut-off values to predict significant non-left main coronary artery stenosis.  Summary estimates were obtained using a random-effects model.  The 17 studies used in this analysis enrolled 3,920 patients with 4,267 lesions.  The weighted overall mean MLA cut-off value was 2.58 mm2.  The pooled MLA sensitivity that predicted functionally significant coronary stenosis was 0.75 (CI: 0.72 to 0.77) and the specificity was 0.66 (CI: 0.64 to 0.68).  The positive likelihood ratio (LR) was 2.33 (CI: 2.06 to 2.63) and LR (-) was 0.33 (CI: 0.26 to 0.42).  The pooled diagnostic OR (DOR) was 7.53 (CI: 5.26 to 10.76) and the area under the summary receiver operating characteristic curve (ROC) for all the trials was 0.782 with a Q point of 0.720.  Meta-regression analysis demonstrated that an FFR cut-off point of 0.75 was associated with a 4 times higher diagnostic accuracy compared to that of 0.80 (relative DOR: 3.92; 95 % CI: 1.25 to 12.34).  The authors concluded that IVUS-derived MLA has limited diagnostic accuracy in predicting functionally significant coronary artery disease and cannot be used alone to make the decision whether or not to proceed with the PCI of intermediate non-left main coronary artery stenosis.

Regulatory Status

N/A

Rationale

Angiograms only produce a silhouette of the luminal wall. In contrast, intravascular ultrasound (IVUS) can provide information on the composition of the arterial wall and the amount of remaining atherosclerotic plaque. Therefore, IVUS has been extensively investigated as a technique to determine plaque composition, mechanism of action of PTCA, and to determine residual plaque at the end of a procedure; i.e., the acute procedural success. The major limitation of transcatheter revascularization techniques (i.e., angioplasty, atherectomy with and without stent placement) is the high rate of restenosis, thought to be related in part to the adequacy of the plaque disruption or removal. Therefore, increasing the acute procedural success, as measured by the minimal luminal diameter or the lumen cross-sectional area, has been investigated as a risk factor for future restenosis and as a tool to guide further patient management.

IVUS has probably been most extensively investigated as an adjunct to stent placement. The early experience with stents was plagued by a high acute restenosis rate related to thrombosis. Therefore, patients receiving stents required acute thrombolytic therapy (i.e., heparin and coumadin), which required an increased length of hospitalization and was associated with an increased incidence of complications. The results of IVUS suggested that the risk of thrombosis was in part related to improper stent placement or incomplete stent expansion. The use of IVUS to guide stent placement has now obviated the need for thrombolytic therapy. For example, Colombo and associates reported that 70% of stents that were associated with apparent success as judged by angiography, underwent further expansion to an optimal <20% residual stenosis, as judged by IVUS. (1) Patients were successfully discharged without systemic anticoagulation. A series of subsequent trials have also validated the use of IVUS to identify those patients with acute procedural success who could forego aggressive anticoagulational therapy. (2)

Restenosis is a similar concern in patients undergoing atherectomy. Similarly, IVUS has been used to determine the adequacy of atherectomy. For example, even when adequate angiogram results are present, IVUS can demonstrate significant residual atherosclerotic plaque and guide its removal in order to achieve the largest size lumen without damaging underlying vascular media or intima. Registry data suggest that IVUS-guided atherectomy results in lower rates of restenosis. (3)

IVUS has also been investigated as an initial technique to determine plaque composition, and thus guide selection, of revascularization technique, i.e., atherectomy, angioplasty, and/or stent placement. (4,5)

In 2001, the American College of Cardiology published guidelines for percutaneous coronary interventions, which included guidelines for the use of IVUS. (6) The guidelines include class I, II, and III recommendations, with class I defined as “conditions for which there is evidence for and/or general agreement that the procedure or treatment is useful and effective.” Class II is further divided into Class IIa and Class IIb, with class IIa defined as “Conditions for which there is conflicting evidence and/or divergence of opinion about usefulness of a procedure or treatment, but weight of evidence/opinion is in favor of usefulness/efficacy.” For IVUS, the ACC guidelines did not identify any Class I indications, but did identify Class IIa, Class IIb, and Class III indications. The class IIa indications are summarized in the Policy Guidelines section. The supporting text of these guidelines includes the statement, “IVUS is not necessary for all stent procedures. The results of the French Stent Registry study of 2900 patients treated  without coumadin and without IVUS reported a subacute closure rate of 1.8%. In the STARS trial, a subacute closure rate of 0.6% in patients having optimal stent implantation supports the approach that IVUS does not appear to be required routinely in all stent implantations. However, the use of IVUS for evaluating results in high-risk patients (i.e. those patients with multiple stents, impaired TIMI grade flow or coronary flow reserve, and marginal angiographic appearance) appears warranted.”

Promotion of greater diversity and inclusion in clinical research of historically marginalized groups (e.g., People of Color [African-American, Asian, Black, Latino and Native American]; LGBTQIA (Lesbian, Gay, Bisexual, Transgender, Queer, Intersex, Asexual); Women; and People with Disabilities [Physical and Invisible]) allows policy populations to be more reflective of and findings more applicable to our diverse members. While we also strive to use inclusive language related to these groups in our policies, use of gender-specific nouns (e.g., women, men, sisters, etc.) will continue when reflective of language used in publications describing study populations.

Population Reference No. 1

Suplemental Information

N/A

Practice Guidelines And Position Statements

N/A

Medicare National Coverage

https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=56823&ver=11

https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=56500&ver=27

References

1. Colombo A, Hall P, Nakamura S et al. Intracoronary stenting without anticoagulation accomplished with intravascular ultrasound guidance. Circulation 1995; 91(6):1676-88.

2. Russo RJ. Ultrasound-guided stent placement. Cardiol Clin 1997; 15(1):49-61.

3. Timmis SB, Davidson CJ. Intravascular ultrasound in the setting of directional coronary atherectomy and percutaneous transluminal coronary rotational atherectomy. Cardiol Clin 1997; 15(1):39-48.

4. Tenaglia AN. Intravascular ultrasound and balloon percutaneous transluminal coronary angioplasty. Cardiol Clin 1997; 15(1):31-8.

5. Gorge G, Ge J, Erbel R. Role of intravascular ultrasound in the evaluation of mechanisms of coronary interventions and restenosis. Am J Cardiol 1998; 81(12A):91G-95G.

6. Smith SC, Dove JT, Jacobs AK et al. ACC/AHA guidelines for percutaneous coronary interventions (revision of the 1993 PTCA guidelines – executive summary. J Am Coll Cardiol 2001; 37(8):2215-39.

Codes

Applicable Modifiers

N/A

Policy History