Description
Computed tomography angiography is a non-invasive imaging modality that may be used in the evaluation of thoracic vascular problems. Chest CTA (noncoronary) may be used to evaluate vascular conditions, e.g., pulmonary embolism, thoracic aneurysm, thoracic aortic dissection, aortic coarctation, or pulmonary vascular stenosis. The vascular structures as well as the surrounding anatomical structures are depicted by CTA.

OVERVIEW:
CTA and Coarctation of the Aorta — Coarctation of the aorta is a common vascular anomaly characterized by a constriction of the lumen of the aorta distal to the origin of the left subclavian artery near the insertion of the ligamentum arteriosum. The clinical sign of coarctation of the aorta is a disparity in the pulsations and blood pressures in the legs and arms. Chest CTA may be used to evaluate either suspected or known aortic coarctation and patients with significant coarctation should be treated surgically or interventionally.

CTA and Pulmonary Embolism (PE) — Note: D-Dimer blood test in patients at low risk for DVT is indicated prior to CTA imaging. Negative D-Dimer suggests alternative diagnosis in these patients.

CTA has high sensitivity and specificity and is the primary imaging modality to evaluate patients suspected of having acute pulmonary embolism. When high suspicion of pulmonary embolism on clinical assessment is combined with a positive CTA, there is a strong indication of pulmonary embolism. Likewise, a low clinical suspicion and a negative CTA can be used to rule out pulmonary embolism.

Low risk is not approved. Low risk is defined as NO to ALL of the following questions with intermediate and high risk defined based on the number of positive responses (Konstantinides, 2020):  

• Evidence of current or prior DVT;
• HR > 100;
• Cancer diagnosis;
• Recent surgery or prolonged immobilization;
• Hemoptysis;
• History of PE;
• Oral hormone use;
• Another diagnosis beside PE is less likely

CTA and Thoracic Aortic Aneurysms —Computed tomographic angiography (CTA) allows the examination of the precise 3-D anatomy of the aneurysm from all angles and shows its relationship to branch vessels. This information is very important in determining the treatment: endovascular stent grafting or open surgical repair.

CTA and Thoracic Aorta Endovascular Stent-Grafts —CTA is an effective alternative to conventional angiography for postoperative follow-up of aortic stent grafts. It is used to review complications after thoracic endovascular aortic repair. CTA can detect luminal and extraluminal changes to the thoracic aorta after stent-grafting and can be performed efficiently with fast scanning speed and high spatial and temporal resolution.

Policy 
INDICATIONS FOR CHEST CTA
Chest computed tomography angiography (CTA) is ordered for evaluation of the intrathoracic blood vessels. Chest CT and chest CTA should not be approved at the same time.

Suspected Pulmonary Embolism (PE)^1,2,3,4,5

• High risk for PE based on shock or hypotension
• Intermediate or high risk as determined by the parameters detailed in Overview section
• Positive D-dimer^2,4

Vascular Disease

• Superior vena cava (SVC) syndrome⁶
• Subclavian Steal Syndrome after positive or inconclusive ultrasound^7,8
• Thoracic Outlet Syndrome^9,10
• Takayasu’s arteritis¹¹
• Clinical concern for Acute Aortic dissection^12,13
  • Sudden painful ripping sensation in the chest or back and may include:
    • New diastolic murmur.
    • Cardiac tamponade.
    • Distant heart sounds.
    • Hypotension or shock.

Initial/Screening for Thoracic Aortic Disease^14,15,16

• Echocardiogram or chest X-ray show aneurysm
• Initial study for a suspected aneurysm
• Screening of first-degree relatives of individuals with a thoracic aortic aneurysm (defined as > 50% above normal) or dissection
  • Known connective tissue disease or genetic conditions that predispose to aortic aneurysm or dissection (e.g., Marfan syndrome, Ehlers Danlos or Loeys-Dietz syndromes)
• Screening of the thoracic aorta after a diagnosis of a bicuspid aortic valve (dilation of the ascending aorta may not be seen on echocardiogram)¹⁷
  • If normal, re-image 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^14,15,16

• 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 > 0.5 cm/year — Every six months
  • Genetically mediated (Marfans syndrome, aortic root or ascending aorta) (in cm)
    • 3.5 to 4.4 annual
    • 4.5 to 5.0 or growth rate > 0.5 cm/year — Every six months
    • Surgery generally recommended over 5.0 cm
  • Descending aorta (in cm)¹⁸
    • 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 post either root repair or AVR plus ascending aortic root/arch repair: baseline post-op, then annually
• 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 (Chest Magnetic Resonance Angiography preferred if pediatrics or repeat imaging)

• Thoracic malformation on other imaging (chest x-ray, echocardiogram, gastrointestinal study, or inconclusive CT)^19,20,21,22
• Congenital heart disease with pulmonary hypertension²³ or vascular anomalies
• Pulmonary sequestration²⁴

Pulmonary Hypertension based on other testing^25,26

• Echocardiogram
• Right heart catheterization

Atrial fibrillation with ablation planned²⁷

Preoperative/procedural evaluation

• Pre-operative evaluation for a planned surgery or procedure

Post-operative/procedural evaluation

• Post-operative complications^28,29
• Routine post-operative^30,31
  • Thoracic endovascular or open surgical aneurysm repair
    • 1 month
    • More frequent follow-up/possible intervention if complication detected
    • If stable, annual for 5 years

Chest CTA and Abdomen CTA or Abdomen/Pelvis CTA

• Transcatheter aortic valve replacement (TAVR)^13,32
• Acute aortic dissection¹²
• Takayasu’s arteritis¹¹
• Post-operative complications^28,29

References 

1. Achenbach S, Delgado V, Hausleiter J, et al. SCCT expert consensus document on computed tomography imaging before transcatheter aortic valve implantation (TAVI)/transcatheter aortic valve replacement (TAVR). J Cardiovasc Comput Tomogr. 2012; 6(6):366-80.
2. American College of Chest Physicians (ACCP). Choosing Wisely®: Five things physicians and patients should question. 2013. Retrieved from http://www.choosingwisely.org/clinician-lists/american-college-chest-physicians-american-thoracic-society-chest-ct-angiography-to-evaluate-possibly-pulmonary-embolism/.
3. American College of Radiology (ACR). ACR Appropriateness Criteria®. Retrieved from https://acsearch.acr.org/list. 2020.
4. American College of Radiology (ACR). ACR Appropriateness Criteria®: Imaging for transcatheter aortic valve replacement. ACR, 2017. Retrieved from https://acsearch.acr.org/docs/3082594/Narrative/.
5. American College of Radiology (ACR). ACR Appropriateness Criteria® Thoracic Outlet Syndrome. Published 2019. Accessed August 3, 2021. https://acsearch.acr.org/docs/3083061/Narrative/.
6. Ascha M, Renapurkar RD, Tonelli AR. A review of imaging modalities in pulmonary hypertension. Ann Thorac Med. 2017; 12(2):61–73.
7. Barman M. Acute aortic dissection. Euro Soc Cardiol. 2014; 12(25):02.
8. Bennet KM, Kent KC, Schumaker J, et el. Targeting the most important complications in vascular surgery. J Vasc Surg. 2017; 65(3):793-803.
9. 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. 2018;156(2):e41-e74. doi:10.1016/j.jtcvs.2018.02.115
10. Braverman A, Thompson R, Sanchez L. Diseases of the aorta. In: Braunwald’s heart disease, 9th ed, Bonow R, Mann D, Zipes D, Libby P (Eds), Elsevier, Philadelphia 2011. p.1309.
11. Choudhury M. Postoperative Management of Vascular Surgery Patients: A Brief Review. Clin Surg. 2017; 2:1584.
12. Corrigan D, Prucnal C, Kabrhel C. Pulmonary embolism: the diagnosis, risk-stratification, treatment and disposition of emergency department patients. Clin Exp Emerg Med. 2016; 3(3): 117–125.
13. 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. 2014; 35(41):2873.
14. Ferreira TDA, Chagas ISS, Ramos RTT, et al. Congenital thoracic malformations in pediatric patients: two decades of experience. J Bras Pneumol. 2015; 41(2):196-199.
15. Friedman T, Quencer KB, Kishore SA, et al. Malignant Venous Obstruction: Superior Vena Cava Syndrome and Beyond. Semin Intervent Radiol. 2017; 34(4):398.
16. Hannuksela M, Eva-Lena Stattin E, Johansson B, et al. Screening for familial thoracic aortic aneurysms with aortic imaging does not detect all potential carriers of the disease. Aorta (Stamford). 2015 Feb; 3(1): 1–8.
17. Hellinger JC, Daubert M, Lee EY, et al. Congenital thoracic vascular anomalies: Evaluation with state-of-the-art MR imaging and MDCT. Radiol Clin N Am. 2011; 49:969-996.
18. 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. 2010; 121(13):e266.
19. Karaosmanoglu AD, Khawaja RD, Onur MR, et al. CT and MRI of aortic coarctation: Pre- and postsurgical findings. AJR Am J Roentgenol. March 2015; 204(3):W224-33. Retrieved from https://www.ajronline.org/doi/10.2214/AJR.14.12529.
20. Keser G, Direskeneli H, Aksu K. Management of Takayasu arteritis: a systematic review. Rheumatology. 2014; 53(5):793–801.
21. Kirsch J, Brown RKJ, Henry TS, et al. ACR Appropriateness Criteria® Acute Chest Pain-Suspected Pulmonary Embolism. JACR. 2017; 14(Suppl 5):S2-S12.
22. Kolandaivelu A. Role of Cardiac Imaging (CT/MR) Before and After RF Catheter Ablation in Patients with Atrial Fibrillation. J Atr Fibrillation. 2012 Aug-Sep; 5(2):523.
23. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS): The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC). Euro Heart J. 2020; 41(4):543-603.
24. Konstantinides SV, Torbicki A, Agnelli G, et al. 2014 ESC Guidelines on the diagnosis and management of acute pulmonary embolism: The Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Euro Heart J. 2014; 35(43):3033–3080.
25. Lawrence PF. Society for Vascular Surgery: Recommendations for follow-up after vascular surgery procedures. SVS Practice Guidelines. 2018; 68(1):1. Retrieved from https://www.jvascsurg.org/article/S0741-5214(18)31069-3/fulltext.
26. Long Q, Zha Y, Yang Z. Evaluation of pulmonary sequestration with multidetector computed tomography angiography in a select cohort of patients: A retrospective study. Clinics (Sao Paul). 2016; 71(7):392–398.
27. Osiro S, Zurada A, Gielecki J, et, al. A review of subclavian steal syndrome with clinical correlation. Med Sci Monit. 2012;18(5): RA57-RA63.
28. Pascall E, Tulloh RMR. Pulmonary hypertension in congenital heart disease. Future Cardiol. 2018; 14(4): 343–353.
29. Poletto E, Mallon MG, Stevens RM, et al. Imaging review of aortic vascular rings and pulmonary sling. J Am Osteopath Coll Radiol. 2017; 6(2):5-14.
30. Potter BJ, Pinto DS. Subclavian Steal Syndrome. Circulation. 2014; 129:2320–2323.
31. Povlsen S, Povlsen B. Diagnosing thoracic outlet syndrome: Current approaches and future directions. Diagnostics (Basel). 2018; 8(1):21.
32. Rose-Jones, LJ, Mclaughlin VV. Pulmonary hypertension: Types and treatments. Curr Cardiol Rev. 2015; 11(1):73-79.
33. Sancak T. The role of contrast enhanced three-dimensional MR angiography in pulmonary sequestration. Interactive Cardiovascular and Thoracic Surgery. 2003;2(4):480-482. doi:10.1016/S1569-9293(03)00118-X.
34. Uthof H, Pena C, Katzen BT, et, el. Current clinical practice in postoperative endovascular aneurysm repair imaging surveillance. J Vasc Intervent Radiol. 2012; 23(9):1152–1159.
35. Zierler RE, Jordan WD, Lal BK, et al. The Society for Vascular Surgery practice guidelines on follow-up after vascular surgery arterial procedures. 2018 Jul 1; 68(1):256-84.

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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