GENERAL INFORMATION  

It is an expectation that all patients receive care/services from a licensed clinician. All appropriate supporting documentation, including recent pertinent office visit notes, laboratory data, and results of any special testing must be provided. If applicable: All prior relevant imaging results and the reason that alternative imaging cannot be performed must be included in the documentation submitted. 

Where a specific clinical indication is not directly addressed in this guideline, medical necessity determination will be made based on widely accepted standard of care criteria. These criteria are supported by evidence-based or peer-reviewed sources such as medical literature, societal guidelines and state/national recommendations.

IMPORTANT NOTE
When vascular imaging of the aorta and both legs, i.e., CTA aortogram and runoff is desired (sometimes incorrectly requested as Abd/Pelvis CTA & Lower Extremity CTA Runoff), only one authorization request is required, using CPT Code 75635 Abdominal Arteries CTA. This study provides for imaging of the abdomen, pelvis, and both legs The CPT code description is CTA aorto-iliofemoral runoff; abdominal aorta and bilateral ilio-femoral lower extremity runoff. 

When separate requests for CTA abdomen and CTA Pelvis are encountered for processes involving both the abdomen and pelvis (but do NOT need to include legs/runoff), they need to be resubmitted as a single Abdomen/Pelvis CTA (to avoid unbundling). Otherwise, the exam should be limited to the appropriate area (i.e., abdomen OR pelvis) that includes the area of concern.

INDICATIONS
Peripheral Vascular Disease^1,2,3,4

• For evaluation of known or suspected lower extremity arterial disease):
  • For known or suspected peripheral arterial disease (such as claudication, or clinical concern for vascular causes of ulcers) when non-invasive studies (pulse volume recording, ankle-brachial index, toe brachial index, segmental pressures, or doppler ultrasound) are abnormal or equivocal OR
  • For critical limb ischemia with ANY of the below clinical signs of peripheral artery disease (prior ultrasound is not needed; if done and negative, CTA should still be approved)^5,6
    • Ischemic rest pain
    • Tissue loss
    • Gangrene
  • After stenting or surgery with signs of recurrent symptoms, abnormal ankle/brachial index, abnormal or indeterminate arterial Doppler, OR abnormal or indeterminate pulse volume recording

NOTE: When vascular imaging of the aorta and both legs, i.e., CTA aortogram and runoff is desired (sometimes incorrectly requested as Abd/Pelvis CTA & Lower Extremity CTA Runoff), only one authorization request is required, using CPT Code 75635 CTA Aortogram.

This study provides for imaging of the abdomen, pelvis, and both legs. A separate authorization for Lower Extremity CTA is NOT needed.

Pre-operative/Procedure Evaluation

• Evaluation of interventional vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia

Post-Operative/Post-Procedural Evaluation

• Evaluation of post-operative complications, e.g., pseudoaneurysms related to surgical bypass grafts, vascular stents, and stent-grafts
• Follow-up study may be needed to help evaluate apatient’s progress after treatment,

procedure, intervention, or surgery.

• Documentation requires a medical reason that clearly indicates why additional imaging is needed for the type and area(s) requested.

Further Evaluation of Indeterminate Findings on Prior Imaging
Unless follow-up is otherwise specified within the guideline:

• For initial evaluation of an inconclusive finding on a prior imaging report that requires further clarification
• One follow-up exam of a prior indeterminate MR/CT finding to ensure no suspicious interval change has occurred. (No further surveillance unless specified as highly suspicious or change was found on last follow-up exam)

Genetic Syndromes and Rare Diseases

• Williams Syndrome:⁷
  • When there is concern for vascular disease (including renal artery stenosis) based on abnormal exam or imaging findings (such as diminished pulses, bruits or signs of diffuse thoracic aortic stenosis)
• For other syndromes and rare diseases not otherwise addressed in the guideline, coverage is based on a case-by-case basis using societal guidance

Combinations Studies
Abdominal Aorta CT Angiography With Lower Extremity Runoff and Chest CTA

• To evaluate for an embolic source of lower extremity vascular disease when other imaging such as echocardiography suggests a cardiac source of the embolism
• Williams Syndrome: When there is concern for vascular disease (including renal artery stenosis) based on abnormal exam or imaging findings (such as diminished pulses, bruits or signs of diffuse thoracic aortic stenosis)⁷

Rationale
BACKGROUND
Contraindications and Preferred Studies

• Contraindications and reasons why a CT/CTA cannot be performed may include: impaired renal function, significant allergy to IV contrast, pregnancy (depending on trimester).
• Contraindications and reasons why an MRI/MRA cannot be performed may include: impaired renal function, claustrophobia, non-MRI compatible devices (such as non- compatible defibrillator or pacemaker), metallic fragments in a high-risk location, patient exceeds weight limit/dimensions of MRI machine.

Suspected Peripheral Arterial Disease
CTA (or MRA) is an excellent tool to diagnose lower extremity peripheral arterial disease (PAD). Benefits include the fast-scanning time and accurate detection of occlusions and stenosis. According to the Society for Vascular Surgery guidelines, “Measurement of the ankle-brachial index (ABI) is the primary method for establishing the diagnosis of PAD. An ABI of ≤ 0.90 has been demonstrated to have high sensitivity and specificity for the identification of PAD compared with the gold standard of invasive arteriography.” (2) The presence of a normal ABI at rest and following exercise almost excludes atherosclerotic disease as a cause for leg claudication.^1,7

When an ABI is > 1.40 (suggesting noncompressible calcified vessels) and clinical suspicion is high, other tests such as toe-brachial index < 8, a resting toe pressure < 40 mm Hg, a systolic peak posterior tibial artery flow velocity < 10 cm/s may be used. “In symptomatic patients in whom revascularization treatment is being considered, we recommend anatomic imaging studies, such as arterial duplex ultrasound, CTA, MRA, and contrast arteriography.”

(2) This later statement is accompanied by a “B” (moderate) rating for the accompanying evidence (“A” = high, “C” = low) “In patients with limited renal function or planned surgical intervention, noninvasive imaging tests (particularly MRA and CTA) may obviate the need for diagnostic catheter angiography to visualize the location and severity of peripheral vascular disease.”²

Follow-up imaging post vascular surgery procedures have not been well researched without clear surveillance protocols in place. Clinical exam, ABI and EUS within the first month of endovascular therapy are generally recommended to assess for residual stenosis, and again at 6 and 12 months, then annually. More sophisticated imaging with CTA, MRA, or invasive catheter angiography is reserved for complex cases.⁸
 

References

1. Azene E M, Steigner M L, Aghayev A, Ahmad S, Clough R E et al. AACR Appropriateness Criteria® Lower Extremity Arterial Claudication-Imaging Assessment for Revascularization: 2022 Update. Journal of the American College of Radiology. 2022; 19: S364 - S373. 10.1016/j.jacr.2022.09.002.
2. Conte M S, Pomposelli F B, Clair D G, Geraghty P J, McKinsey J F et al. Society for Vascular Surgery practice guidelines for atherosclerotic occlusive disease of the lower extremities: management of asymptomatic disease and claudication. J Vasc Surg. 2015; 61: 2s-41s. 10.1016/j.jvs.2014.12.009.
3. Singh-Bhinder N, Kim D H, Holly B P, Johnson P T, Hanley M et al. ACR Appropriateness Criteria® Nonvariceal Upper Gastrointestinal Bleeding. Journal of the American College of Radiology. 2017; 14: S177 - S188. 10.1016/j.jacr.2017.02.038.
4. Werncke T, Ringe K I, von Falck C, Kruschewski M, Wacker F. Diagnostic confidence of run-off CT- angiography as the primary diagnostic imaging modality in patients presenting with acute or chronic peripheral arterial disease. PLoS One. 2015; 10: e0119900. 10.1371/journal.pone.0119900.
5. Shishehbor M H, White C J, Gray B H, Menard M T, Lookstein R et al. Critical Limb Ischemia: An Expert Statement. J Am Coll Cardiol. 2016; 68: 2002-2015. 10.1016/j.jacc.2016.04.071.
6. Browne W F, Sung J, Majdalany B S, Khaja M S, Calligaro K et al. ACR Appropriateness Criteria® Sudden Onset of Cold, Painful Leg: 2023 Update. Journal of the American College of Radiology. 2023; 20: S565 - S573. 10.1016/j.jacr.2023.08.012.
7. Morris C. Williams Syndrome. [Updated 2023 Apr 13]. GeneReviews® [Internet].2023.

Coding Section 

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive. 

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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