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.

Purpose
CTA
Computed tomography angiography (CTA) generates images of the arteries that can be evaluated for evidence of stenosis, occlusion, or aneurysms with the use of ionizing
radiation, which is a potential hazard in patients with impaired renal function.

Special Note
When vascular imaging of the aorta and both legs is desired (sometimes incorrectly requested as Abdomen and Pelvis CTA & Lower Extremity CTA), only one authorization request is required, using CPT Code 75635 CT Angiography, Abdominal Aorta with Lower Extremity Runoff. This study provides for imaging of the abdomen, pelvis, and both legs.

Policy
INDICATIONS FOR ABDOMEN PELVIS CT
ANGIOGRAPHY/VENOGRAPHY (CTA/CTV)
Abdominal Aortic Disease
Abdominal Aortic Aneurysm

• Asymptomatic known or suspected abdominal aortic aneurysms when prior ultrasound is inconclusive or insufficient AND a reason CTA is needed rather than CT has been provided, such as complex vascular anatomy or suspected complications.
• Symptomatic known or suspected Abdominal Aortic Aneurysm^1,2,3
  • Symptoms may include:
  • Abrupt onset of severe sharp or stabbing pain in the chest, back or abdomen
  • Acute abdominal or back pain with a pulsatile or epigastric mass
  • Acute abdominal or back pain and at high risk for aortic aneurysm and/or aortic syndrome (risk factors include hypertension, atherosclerosis, prior cardiac or aortic surgery, underlying aneurysm, connective tissue disorder [e.g., Marfan syndrome, vascular form of Ehlers-Danlos syndrome, Loeys-Dietz syndrome], and bicuspid aortic valve)^1,2,4

Aortic Syndromes
For initial diagnosis of suspected and follow-up of known aortic syndromes, including aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer

• Frequency for follow up is as clinically indicated

Postoperative Follow-up of Aortic Repair^1,2
Follow-up for post-endovascular repair (EVAR) or open repair of AAA or abdominal extent of iliac artery aneurysms at the following intervals (CT preferred for routine follow-up):

• Routine, baseline post-EVAR study when a reason CTA rather than CT is needed has been provided such as complex anatomy or suspected complications:
  • Within one month of procedure
  • Continued follow up imaging at the following intervals:
    • If no endoleak or sac enlargement is seen:
      • Annually monitor with ultrasound
        • When US is abnormal or insufficient CT/MR can be using to monitor annually
      • Every 5 years monitor with CT/MR
    • If type II endoleak or sac enlargement is seen at any point in time (US not needed):
      • Monitor every 6 months x 2 years, then annually (does not require US)
• Routine follow up after open repair of AAA when a reason CTA is needed rather than CT has been provided such as complex vascular anatomy or suspected complications:
  • Within 1 year postoperatively then
  • Annually monitor with ultrasound
    • When US is abnormal or insufficient CT/MR can be used to monitor annually
  • Every 5 years monitor with CT/MR
• If symptomatic or imaging shows increasing, or new findings related to stent graft – more frequent imaging may be needed as clinically indicated
• Suspected complications, such as new onset lower extremity claudication, ischemia, or reduction in ABI after aneurysm repair.

Ischemia or Hemorrhage

• To determine the vascular source of retroperitoneal hematoma or hemorrhage when CT is insufficient to determine the source (CT rather than MRA/CTA is the modality of choice for diagnosing hemorrhage)⁵
• Evaluation of known or suspected mesenteric ischemia/ischemic colitis⁶
• To localize active lower gastrointestinal bleeding, or non-localized intermittent bleeding in a hemodynamically stable patient when colonoscopy was unsuccessful, contraindicated or unavailable^7,8,9

Other Vascular Abnormalities

• Initial evaluation of inconclusive vascular findings on prior imaging
• For evaluation or monitoring of non-aortic large vessel or visceral vascular disease when ultrasound is inconclusive and imaging of both the abdomen and pelvis are needed^1,2,4,10
  • Includes abnormalities such as aneurysm, dissection, arteriovenous malformations (AVM), vascular fistula, intramural hematoma, compression syndromes and vasculitis involving any of the following: inferior vena cava, superior/inferior mesenteric, celiac, hepatic, splenic or renal arteries/veins
• As part of an extracardiac vascular assessment in patients with spontaneous coronary artery dissection (SCAD), can be done at time of coronary angiography¹¹
• Suspected complications of known aneurysm as evidenced by clinical findings such as new onset of abdominal pain

Venous Disease

• Suspected venous thrombosis (including renal vein thrombosis and/or portal venous thrombosis) if previous studies (such as ultrasound) have not resulted in a clear
• diagnosis¹²
• Known/suspected May-Thurner syndrome (iliac vein compression syndrome)^13,14
• Evaluation of suspected pelvic vascular disease or pelvic congestive syndrome with prior inconclusive ultrasound¹⁵
• For unexplained lower extremity edema (typically unilateral or asymmetric) with negative or inconclusive Abdomen and/or Pelvis CT¹⁶

Evaluation of Tumor

• When needed for clarification of vascular invasion from tumor (including suspected renal vein thrombosis)¹⁷
• For imaging of the deep inferior epigastric arteries prior to breast reconstructive surgery

Pre-Operative Evaluation and/or Pre-Procedural Evaluation

• Evaluation of interventional vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
• For imaging of the deep inferior epigastric arteries for surgical planning (breast reconstructive surgery)¹⁵
• Evaluation of vascular anatomy prior to solid organ transplantation
• Prior to repair of abdominal aortic aneurysm
• Evaluation prior to endovascular aneurysm repair (EVAR)
• Evaluation prior to Transcatheter Aortic Valve Replacement (TAVR)¹⁸

Post-Operative Evaluation and/or Post-Procedural Evaluation
Unless otherwise specified within the guideline:

• Follow-up study may be needed to help evaluate a patient’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.
• Evaluation of endovascular/interventional abdominal vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
• Evaluation of post-operative complications, e.g., pseudoaneurysms, related to surgical bypass grafts, vascular stents, and stent-grafts in abdomen and pelvis
• Suspected complications of IVC filters

Genetic Syndromes and Rare Diseases

• For patients with fibromuscular dysplasia (FMD):^19,20
  • One-time vascular study from brain to pelvis
• Vascular Ehlers-Danlos syndrome:^21,22
  • At diagnosis and then every 18 months
  • More frequently if abnormalities are found
• Marfan syndrome:²³
  • At diagnosis and then every 3 years
  • More frequently (annually) if EITHER: history of dissection, dilation of aorta beyond aortic root OR aortic root/ascending aorta are not adequately visualized on TTE (i.e., advanced imaging is needed to monitor the thoracic aorta)^1,24
• Loeys-Dietz:
  • At diagnosis and then every two years
  • More frequently if abnormalities are found²⁵
• Williams Syndrome:²⁶
  • 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)
• Neurofibromatosis Type 1 (NF-1):²⁷
  • Development of hypertension (including concern for renal artery stenosis)
• Takayasu's Arteritis:²⁸
  • For evaluation at diagnosis then as clinically indicated
• For other syndromes and rare diseases not otherwise addressed in the guideline, coverage is based on a case-by-case basis using societal guidance.

Combination Studies
Abdomen and Pelvis CTA and Abdomen and Pelvis CT (or MRI)

• When needed for clarification of vascular invasion from tumor (including suspected renal vein thrombosis)

Brain/Neck/Chest/Abdomen and Pelvis CTA

• For patients with fibromuscular dysplasia (FMD), a one-time vascular study from brain to pelvis^19,20
• Vascular Ehlers-Danlos syndrome: At diagnosis and then every 18 months; more frequently if abnormalities are found^21,22
• Loeys-Dietz: at diagnosis and then every two years, more frequently if abnormalities are found²⁹
• For assessment in patients with spontaneous coronary artery dissection (SCAD), can be done at time of coronary angiography¹¹

Chest and Abdomen or Abdomen and Pelvis CTA

• Evaluation prior to endovascular aneurysm repair (EVAR) when thoracic involvement is present
• Evaluation prior to Transcatheter Aortic Valve Replacement (TAVR)¹⁸
• Marfan syndrome:²³
  • At diagnosis and every 3 years
  • More frequently (annually) if EITHER: history of dissection, dilation of aorta beyond aortic root OR aortic root/ascending aorta are not adequately visualized on TTE (i.e., advanced imaging is needed to monitor the thoracic aorta)^1,24
• Williams Syndrome²⁶
  • 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)
• Acute aortic dissection³⁰
• Significant post-traumatic or post-procedural vascular complications reasonably expected to involve the chest, abdomen and pelvis

Neck/Chest/Abdomen and Pelvis CTA

• Takayasu's Arteritis: For evaluation at diagnosis then as clinically indicated²⁸

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 needed unless specified as highly suspicious or change was found on last follow-up exam.)

Rationale
Abdominal Aneurysms and General Guidelines for Follow-Up
The normal diameter of the suprarenal abdominal aorta is 3.0 cm and that of the infrarenal is 2.0 cm. Aneurysmal dilatation of the infrarenal aorta is defined as diameter ≥ 3.0 cm or dilatation of the aorta ≥ 1.5x the normal diameter. Evaluation of AAA can be accurately made by ultrasound which can detect and size AAA with the advantage of being relatively inexpensive, noninvasive, and not requiring iodinated contrast. The limitations are overlying bowel gas which can obscure findings and the technique is operator dependent. Ultrasound is used to screen for and to monitor aneurysms*. CT is used when US is inconclusive or insufficient. When there are suspected complications, complex anatomy and/or surgery is planned, CTA/MRA is preferred.

Risk factors for AAA include smoking history, age, male gender, family history of AAA (first degree relative) and personal history of vascular disease. Risk factors for rupture include female gender, large initial aneurysm diameter, low FEV, current smoking history, elevated mean blood pressure and patients on immunosuppression after major organ transplantation. The Society of Vascular Surgery recommends elective repair of AAA ≥ 5.5 cm in patients at low or acceptable surgical risk.²

Ultrasound Screening Intervals
From¹

• Aneurysm size 2.5 – 3 cm, every 10 years
• Aneurysm size 3.0 – 3.9 cm, every 3 years
• Aneurysm size 4.0 – 4.9 cm, annually
• Aneurysm size 5.0 – 5.4 cm, every 6 months

Iliac Artery Aneurysm
An iliac artery aneurysm is dilatation of the iliac artery to more than 1.5 times its normal diameter (common iliac artery ≥ 17 mm in men, ≥ 15 mm in women, internal iliac artery > 8 mm.) Surveillance is extrapolated from AAA surveillance and can be done by CTA if ultrasound is not successful.¹⁰

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 noncompatible defibrillator or pacemaker), metallic fragments in a high-risk location, patient exceeds weight limit/dimensions of MRI machine.

References 

1. Isselbacher E M, Preventza O, III J H B, Augoustides J G, Beck A W et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease. Journal of the American College of Cardiology. 2022; 80: e223-e393. doi:10.1016/j.jacc.2022.08.004.
2. Chaikof E L, Dalman R L, Eskandari M K, Jackson B M, Lee W A et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. Journal of Vascular Surgery. 2018; 67: 2-77.e2. 10.1016/j.jvs.2017.10.044.
3. Murillo H, Molvin L, Chin A, Fleischmann D. Aortic Dissection and Other Acute Aortic Syndromes: Diagnostic Imaging Findings from Acute to Chronic Longitudinal Progression. RadioGraphics. 2021; 41: 425 - 446. 10.1148/rg.2021200138.
4. Juntermanns B, Bernheim J, Karaindros K, Walensi M, Hoffmann J. Visceral artery aneurysms. Gefasschirurgie. 2018; 23: 19-22. 10.1007/s00772-018-0384-x.
5. Verma N, Steigner M L, Aghayev A, Azene E M, Chong S T et al. ACR Appropriateness Criteria® Suspected Retroperitoneal Bleed. Journal of the American College of Radiology. 2021; 18: S482 - S487. 10.1016/j.jacr.2021.09.003.
6. Lam A, Kim Y, Fidelman N, Higgins M, Cash B et al. ACR Appropriateness Criteria® Radiologic Management of Mesenteric Ischemia: 2022 Update. Journal of the American College of Radiology. 2022; 19: S433 - S444. 10.1016/j.jacr.2022.09.006.
7. Strate L, Gralnek I. ACG Clinical Guideline: Management of Patients with Acute Lower Gastrointestinal Bleeding. Am J Gastroenterol. Apr 2016; 111: 459-74. 10.1038/ajg.2016.41.
8. American College of Radiology. ACR Appropriateness Criteria® Radiologic Management of Lower Gastrointestinal Tract Bleeding. 2020; 2022:
9. Clerc D, Grass F, Schäfer M, Denys A, Demartines N. Lower gastrointestinal bleeding-Computed Tomographic Angiography, Colonoscopy or both? World J Emerg Surg. 2017; 12: 1. 10.1186/s13017-016-0112-3.
10. Wanhainen A, Verzini F, Van Herzeele I, Allaire E, Bown M et al. European Society for Vascular Surgery (ESVS) 2019 Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms. European Journal of Vascular and Endovascular Surgery. 2019; 57: 8-93. 10.1016/j.ejvs.2018.09.020.
11. Teruzzi G, Santagostino Baldi G, Gili S, Guarnieri G, Montorsi P. Spontaneous Coronary Artery Dissections: A Systematic Review. 2021; 10: 10.3390/jcm10245925.
12. Mazhar H R, Aeddula N R. Renal Vein Thrombosis [Updated 2023 Jun 12]. StatPearls [Internet]. Treasure Island (FL). 2023;
13. Knuttinen M, Naidu S, Oklu R, Kriegshauser S, Eversman W et al. May-Thurner: diagnosis and endovascular management. Cardiovascular diagnosis and therapy. 2017; 7: S159-S164.
14. Shammas N, Jones-Miller S, Kovach T, Radaideh Q, Patel N et al. Predicting Significant Iliac Vein Compression Using a Probability Scoring System Derived from Minimal Luminal Area on Computed Tomography Angiography in Patients 65 Years of Age or Younger. The Journal of invasive cardiology. 2021; 33: E16-E18.
15. American College of Radiology. ACR Appropriateness Criteria® Imaging of Deep Inferior Epigastric Arteries for Surgical Planning (Breast Reconstruction Surgery). 2023; 2023:
16. Gasparis A, Kim P, Dean S, Khilnani N, Labropoulos N. Diagnostic approach to lower limb edema. Phlebology. Oct 2020; 35: 650-655. 10.1177/0268355520938283.
17. Čertík B, Třeška V, Moláček J, Šulc R. How to proceed in the case of a tumour thrombus in the inferior vena cava with renal cell carcinoma. Cor et Vasa. 2015; 57: e95 - e100. https://doi.org/10.1016/j.crvasa.2015.02.015.
18. Hedgire S, Saboo S, Galizia M S, Aghayev A, Bolen M A et al. ACR Appropriateness Criteria® Preprocedural Planning for Transcatheter Aortic Valve Replacement: 2023 Update. Journal of the American College of Radiology. 2023; 20: S501 - S512. 10.1016/j.jacr.2023.08.009.
19. Gornik H L, Persu A, Adlam D, Aparicio L S, Azizi M et al. First International Consensus on the diagnosis and management of fibromuscular dysplasia. Vascular Medicine. 2019; 24: 164 - 189. 10.1177/1358863X18821816.
20. Kesav P, Manesh Raj D, John S. Cerebrovascular Fibromuscular Dysplasia - A Practical Review. Vascular health and risk management. 2023; 19: 543-556.
21. Bowen J M, Hernandez M, Johnson D S, Green C, Kammin T et al. Diagnosis and management of vascular Ehlers-Danlos syndrome: Experience of the UK national diagnostic service, Sheffield. European journal of human genetics : EJHG. 2023; 31: 749-760. 10.1038/s41431-023-01343-7.
22. Byers P. Vascular Ehlers-Danlos Syndrome. [Updated 2019 Feb 21]. GeneReviews® [Internet]. 2019;
23. Dietz H. FBN1-Related Marfan Syndrome. [Updated 2022 Feb 17]. GeneReviews® [Internet]. 2022;
24. Weinrich J M, Lenz A, Schön G, Behzadi C, Molwitz I et al. Magnetic resonance angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome. PLOS ONE. 2022; 17: true. https://doi.org/10.1371/journal.pone.0262826.
25. Loeys B, Dietz H. Loeys-Dietz Syndrome. [Updated 2018 Mar 1]. GeneReviews® [Internet]. 2018;
26. Morris C. Williams Syndrome. [Updated 2023 Apr 13]. GeneReviews® [Internet]. 2023; 27.
27. Friedman J. Neurofibromatosis 1. [Updated 2022 Apr 21]. GeneReviews® [Internet]. 2022;
28. Maz M, Chung S A, Abril A, Langford C A, Gorelik M et al. 2021 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis. Arthritis Rheumatol. (Hoboken, N.J.). 2021; 73: 1349-1365. 10.1002/art.41774.
29. Loeys B, Dietz H. Loeys-Dietz Syndrome. [Updated 2018 Mar 1]. GeneReviews® [Internet]. 2018;
30. Kicska G, Hurwitz Koweek L, Ghoshhajra B, Beache G, Brown R et al. ACR Appropriateness Criteria® Suspected Acute Aortic Syndrome. Journal of the American College of Radiology. 2021; 18: S474 - S481. 10.1016/j.jacr.2021.09.004.

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.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

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