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.

Policy:
INDICATIONS FOR CHEST MRA
Chest Magnetic Resonance Angiography (MRA) is ordered for evaluation of the intrathoracic blood vessels. Chest MRI and Chest MRA should not be approved at the same time.

Vascular Disease

• Superior vena cava (SVC) syndrome¹
• Subclavian Steal Syndrome after positive or inconclusive ultrasound^2,3
• Thoracic Outlet Syndrome^4-6
• Takayasu’s arteritis⁷
• Clinical concern for acute aortic dissection^8,9
  • Sudden painful ripping sensation in the chest or back and may include
    • New diastolic murmur.
    • Cardiac tamponade.
    • Distant heart sounds.
    • Hypotension or shock.
• For MRPA (MR Pulmonary Angiography) in patients with intermediate pretest probability with a positive D-dimer or high pretest probability (but only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated)
  • Risk can be determined by the parameters detailed in Background section.

Initial/Screening for Thoracic Aortic Disease^10-12

• Echocardiogram or chest x-ray show aneurysm
• Screening of first-degree relatives of individuals with a thoracic aortic aneurysm (defined as > 50% above normal) or dissection
• Evaluation in patients with known or suspected connective tissue disease or genetic condition that predisposes to aortic aneurysm or dissection, such as Marfan’s, Ehlers- Danlos, get a one-time study or for Loeys-Dietz syndrome- allow imaging at diagnosis and then every two years, or more frequently if abnormalities are found (Imaging may include head, neck, chest, abdomen and pelvis)(MRA preferred due to cumulative radiation risk)
• Screening of the thoracic aorta after a diagnosis of a bicuspid aortic valve (dilation of the ascending aorta may not be seen on echocardiogram)^13,14
  • If normal, reimage every three to five years
• Screening of first-degree relatives of patients with a bicuspid aortic valve
• Turner’s syndrome — Screen for coarctation or aneurysm of the thoracic aorta
  • If normal results, screen every 5 – 10 years
  • If abnormal, screen annually
• Suspected vascular cause of dysphagia or expiratory wheezing with other imaging is suggestive or inconclusive

Follow-up after established Thoracic Aneurysm^14-16

• Six months follow-up after initial finding of a dilated thoracic aorta, for assessment of rate of change
  • Aortic Root or Ascending Aorta (in cm)
    • 3.5 to 4.4 — annual
    • 4.5 to 5.5 or growth rate ≥ 0.5cm/year — every 6 months
  • Genetically mediated (Marfan syndrome, Aortic Root or Ascending Aorta) (in cm)
    • 3.5 to 4.4 — annual
    • 4.5 to 5.5 or growth rate ≥ 0.5cm/year — every 6 months
    • Surgery generally recommended over 5.0cm
  • Descending Aorta (in cm)¹⁷
    • 4.0 to 5.0 — annual
    • 5.0 to 6.0 — every 6 months
• Follow-up post medical treatment of aortic dissection:
  • Acute dissection: 1 month, 6 months, then annually
  • Chronic dissection: annually
• Follow-up TEVAR surveillance at 1 month, then 1 year post op if stable, then annually
• Follow-up open repair if no residual aortopathy within first post op year, then every 5 years (if have residual aortopathy or abnormal findings on surveillance, annual follow-up if needed)
• Re-evaluation of known ascending aortic dilation or history of aortic dissection with a change in clinical status or cardiac exam or when findings may alter management

Congenital Malformations

• Thoracic malformation on other imaging (chest x-ray, echocardiogram, gastrointestinal study, or inconclusive CT)^15-18
• Congenital heart disease with pulmonary hypertension¹⁹ or vascular anomalies
• Pulmonary Sequestration²⁰

Pulmonary Hypertension based on other testing^21,22

• Echocardiogram
• Right heart catheterization

Atrial fibrillation with ablation planned²³

Pre-operative/procedural evaluation

• Pre-operative evaluation for a planned surgery or procedure
• Pre-transplant CT or CTA/MRA chest approvable for surgical planning (to evaluate for vascular anatomy, mediastinal pathology, malignancy screening etc.)

Post-operative/procedural evaluation

• Post-operative complications^24,25
• See above indications for TAA follow up

Chest MRA and Abdomen MRA or Abdomen/Pelvis MRA

• Transcatheter Aortic Valve Replacement (TAVR)
• Acute aortic dissection
• Takayasu’s arteritis
• Post-operative complications
• To evaluate for an embolic source of lower extremity vascular disease (may also approved as a combination chest MRA, Abdominal MRA and a single LE MRA when LE runoff disease needs to be evaluated as well). Echocardiography is also needed, since the heart is the most commonly reported source of lower extremity emboli i, accounting for 55 to 87 percent of events.

Other Indications
 
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.)

BACKGROUND
Magnetic resonance angiography (MRA) is a noninvasive technique used to provide cross- sectional and projection images of the thoracic vasculature, including large- and medium-sized vessels, e.g., the thoracic aorta. MRA provides images of both normal and diseased blood vessels, and it quantifies blood flow through these vessels. Successful vascular depiction relies on the proper imaging pulse sequences. MRA may use a contrast agent, gadolinium, which is non-iodine-based, for better visualization. It can be used in patients who have history of contrast allergy and who are at high risk of kidney failure.

OVERVIEW
Coarctation of the Aorta — One of the most common congenital vascular anomalies is coarctation of the aorta, characterized by obstruction of the juxtaductal aorta. Clinical symptoms, e.g., murmur, systemic hypertension, difference in blood pressure in upper and lower extremities, absent femoral or pedal pulses, may be present. Gadolinium-enhanced 3D MRA may assist in preoperative planning as it provides angiographic viewing of the aorta, the arch vessels, and collateral vessels. It may also assist in the identification of postoperative complications.

Pulmonary Embolism (PE) — Studies show mixed results regarding the value of MRA versus CTA in detecting pulmonary embolism. A systematic review and meta-analysis found MRA to be inferior to CTA in detecting PE. Therefore, MRA should be used only if CTA is not available or contraindicated in a specific patient.²⁶

Central Venous Thrombosis — CTA/MRA is useful in the identification of venous thrombi. Venous thrombosis can be evaluated by gadolinium-enhanced 3D MRA as an alternative to CTA, which may not be clinically feasible due to allergy to iodine contrast media or renal insufficiency.

MRI and Patent Ductus Arteriosus — Patent ductus arteriosus (PDA) is a congenital heart problem in which the ductus arteriosus does not close after birth. It remains patent allowing oxygen-rich blood from the aorta to mix with oxygen-poor blood from the pulmonary artery. MRI can depict the precise anatomy of a PDA to aid in clinical decisions. It allows imaging in multiple planes without a need for contrast administration. Patients are not exposed to ionizing radiation.

Other MRA Indications — MRA is useful in the assessment for postoperative complications of pulmonary venous stenosis.
 

References:

1. Friedman T, Quencer KB, Kishore SA, Winokur RS, Madoff DC. Malignant Venous Obstruction: Superior Vena Cava Syndrome and Beyond. Semin Intervent Radiol. Dec 2017;34(4):398-408. doi:10.1055/s-0037-1608863
2. Osiro S, Zurada A, Gielecki J, Shoja MM, Tubbs RS, Loukas M. A review of subclavian steal syndrome with clinical correlation. Med Sci Monit. May 2012;18(5):Ra57-63. doi:10.12659/msm.882721
3. Potter BJ, Pinto DS. Subclavian steal syndrome. Circulation. Jun 3 2014;129(22):2320-3. doi:10.1161/circulationaha.113.006653
4. American College of Radiology. ACR Appropriateness Criteria® Thoracic Outlet Syndrome. American College of Radiology. Updated 2019. Accessed November 20, 2022. https://acsearch.acr.org/docs/3083061/Narrative/
5. Chavhan GB, Batmanabane V, Muthusami P, Towbin AJ, Borschel GH. MRI of thoracic outlet syndrome in children. Pediatr Radiol. Sep 2017;47(10):1222-1234. doi:10.1007/s00247-017- 3854-5
6. Povlsen S, Povlsen B. Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions. Diagnostics (Basel). Mar 20 2018;8(1)doi:10.3390/diagnostics8010021
7. Keser G, Direskeneli H, Aksu K. Management of Takayasu arteritis: a systematic review. Rheumatology (Oxford). May 2014;53(5):793-801. doi:10.1093/rheumatology/ket320
8. Barman M. Acute aortic dissection. ESC e-J Cardio Pract. 2014;12(25):02Jul2014. doi:https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-12/Acute- aortic-dissection
9. American College of Radiology. ACR Appropriateness Criteria® Thoracic Aorta Interventional Planning and Follow-up. American College of Radiology. Updated 2017. Accessed November 20, 2022. https://acsearch.acr.org/docs/3099659/Narrative/
10. Erbel R, Aboyans V, Boileau C, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: Document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J. Nov 1 2014;35(41):2873-926. doi:10.1093/eurheartj/ehu281
11. Hannuksela M, Stattin EL, Johansson B, Carlberg B. Screening for Familial Thoracic Aortic Aneurysms with Aortic Imaging Does Not Detect All Potential Carriers of the Disease. Aorta (Stamford). Feb 2015;3(1):1-8. doi:10.12945/j.aorta.2015.14-052
12. Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation. Apr 6 2010;121(13):e266-369. doi:10.1161/CIR.0b013e3181d4739e
13. Borger MA, Fedak PWM, Stephens EH, et al. The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Full online-only version. J Thorac Cardiovasc Surg. Aug 2018;156(2):e41-e74. doi:10.1016/j.jtcvs.2018.02.115
14. Verma S, Siu SC. Aortic dilatation in patients with bicuspid aortic valve. N Engl J Med. May 15 2014;370(20):1920-9. doi:10.1056/NEJMra1207059
15. Ferreira Tda A, Chagas IS, Ramos RT, Souza EL. Congenital thoracic malformations in pediatric patients: two decades of experience. J Bras Pneumol. Mar-Apr 2015;41(2):196-9. doi:10.1590/s1806-37132015000004374
16. Hellinger JC, Daubert M, Lee EY, Epelman M. Congenital thoracic vascular anomalies: evaluation with state-of-the-art MR imaging and MDCT. Radiol Clin North Am. Sep 2011;49(5):969-96. doi:10.1016/j.rcl.2011.06.013
17. Poletto E, Mallon MG, Stevens RM, CM A. Imaging Review of Aortic Vascular Rings and Pulmonary Sling. J Am Osteopath Coll Radiol. 2017;6(2):5-14.
18. Karaosmanoglu AD, Khawaja RD, Onur MR, Kalra MK. CT and MRI of aortic coarctation: pre- and postsurgical findings. AJR Am J Roentgenol. Mar 2015;204(3):W224-33. doi:10.2214/ajr.14.12529
19. Pascall E, Tulloh RM. Pulmonary hypertension in congenital heart disease. Future Cardiol. Jul 2018;14(4):343-353. doi:10.2217/fca-2017-0065
20. Sancak T, Cangir AK, Atasoy C, Ozdemir N. The role of contrast enhanced three-dimensional MR angiography in pulmonary sequestration. Interact Cardiovasc Thorac Surg. Dec 2003;2(4):480-2. doi:10.1016/s1569-9293(03)00118-x
21. Ascha M, Renapurkar RD, Tonelli AR. A review of imaging modalities in pulmonary hypertension. Ann Thorac Med. Apr-Jun 2017;12(2):61-73. doi:10.4103/1817-1737.203742
22. Rose-Jones LJ, McLaughlin VV. Pulmonary hypertension: types and treatments. Curr Cardiol Rev. 2015;11(1):73-9. doi:10.2174/1573403x09666131117164122
23. Kolandaivelu A. Role of Cardiac Imaging (CT/MR) Before and After RF Catheter Ablation in Patients with Atrial Fibrillation. J Atr Fibrillation. Aug-Sep 2012;5(2):523. doi:10.4022/jafib.523
24. Bennett KM, Kent KC, Schumacher J, Greenberg CC, Scarborough JE. Targeting the most important complications in vascular surgery. J Vasc Surg. Mar 2017;65(3):793-803. doi:10.1016/j.jvs.2016.08.107
25. Choudhury M. Postoperative management of vascular surgery patients: a brief review. Clin Surg. 2017;2:1584.
26. Li J, Feng L, Li J, Tang J. Diagnostic accuracy of magnetic resonance angiography for acute pulmonary embolism - a systematic review and meta-analysis. Vasa. 2016;45(2):149-54. doi:10.1024/0301-1526/a000509

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 non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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