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Thoracic aortic aneurysm: How to counsel, when to refer

Cleveland Clinic Journal of Medicine. 2018 June;85(6):481-492 | 10.3949/ccjm.85a.17039
June 1, 2018|Cleveland Clinic Journal of Medicine
Frank Cikach, MD;Milind Y. Desai, MD, FACC, FAHA, FESC;Eric E. Roselli, MD, FACS;Vidyasagar Kalahasti, MD
Author and Disclosure Information

Frank Cikach, MD
Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Milind Y. Desai, MD, FACC, FAHA, FESC
Haslam Family Endowed Chair in Cardiovascular Medicine, Department of Cardiovascular Medicine, Medical Director, Aorta Center, Heart and Vascular Institute, Cleveland Clinic; Professor, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Eric E. Roselli, MD, FACS
Chief, Adult Cardiac Surgery, Surgical Director, Aorta Center, Director, Heart and Vascular Condition Centers, Heart and Vascular Institute, Cleveland Clinic; Clinical Assistant Professor, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Vidyasagar Kalahasti, MD
Director, Marfan and Other Connective Tissue Disorders Clinic, Aorta Center, Heart and Vascular Institute, Cleveland Clinic; Assistant Professor, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Address: Vidyasagar Kalahasti, MD, Heart and Vascular Institute, J1-5, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; kalahav@ccf.org

Dr. Roselli has disclosed consulting for Bolton Medical, Medtronic, Sorin Group, and W.L. Gore & Associates and teaching and speaking for Cook Medical, Edwards Lifesciences, Sorin Group, St. Jude Medical, and Terumo.  

ABSTRACT

Thoracic aortic aneurysm (TAA) is usually clinically silent and progresses slowly until a tipping point is reached, after which the aortic diameter can expand more rapidly and the condition can potentially end in aortic dissection or rupture. Causes include bicuspid aortic valve and genetic syndromes (Marfan, Loeys-Dietz, and Ehlers-Danlos syndromes) and familial associations, but many cases are idiopathic. Clinicians should therefore be alert for clues on chest imaging, and consider screening in first-degree relatives of patients known to have aortic disease. Early referral to a cardiologist specializing in aortic disease is key.

KEY POINTS

  • Screening and referral depend on clinical context. A size-based model to determine screening, referral, follow-up, and management serves most cases but should be modified in the context of connective tissue disease or family history of aneurysm and dissection.
  • Medical management involves strict blood pressure and heart rate control with beta-blockers and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. Activity modifications should be tailored to the individual, although extreme isometric exercises and heavy lifting should be discouraged.
  • Patients with TAA should be followed up annually, unless the patient is presenting for initial evaluation or significant changes are seen with dedicated imaging.

HOW SHOULD PATIENTS BE SCREENED? WHAT FOLLOW-UP IS NECESSARY?

Initial screening and follow-up

Follow-up of TAA depends on the initial aortic size or rate of growth, or both. For patients presenting for the first time with TAA, it is reasonable to obtain definitive aortic imaging with CT or magnetic resonance angiography (MRA), then to repeat imaging at 6 months to document stability. If the aortic dimensions remain stable, then annual follow-up with CT or MRA is reasonable.2

Figure 5. Initial screening and follow-up of thoracic aortic aneurysm.
Figure 5. Initial screening and follow-up of thoracic aortic aneurysm.
MRA may be preferable to CT over the long term to limit radiation exposure.2 Echocardiography should be used if the aortic root or ascending aorta is well visualized, but in most patients the view of the mid to distal ascending aorta is limited. Echocardiography also offers evaluation of left ventricular size and function and allows for follow-up of aortic valve disease.

Our flow chart of initial screening and follow-up is shown in Figure 5.

Screening of family members

In our center, we routinely recommend screening of all first-degree relatives of patients with TAA. Aortic imaging with echocardiography plus CT or MRI should be considered to detect asymptomatic disease.2 In patients with a strong family history (ie, multiple relatives affected with aortic aneurysm, dissection, or sudden cardiac death), genetic screening and testing for known mutations are recommended for the patient as well as for the family members.

If a mutation is identified in a family, then first-degree relatives should undergo genetic screening for the mutation and aortic imaging.2 Imaging in second-degree relatives may also be considered if one or more first-degree relatives are found to have aortic dilation.2

We recommend similar screening of first-degree family members of patients with bicuspid aortic valve aortopathy. In patients with young children, we recommend obtaining an echocardiogram of the child to look for a bicuspid aortic valve or aortic dilation. If an abnormality is detected or suspected, dedicated imaging with MRA to assess aortic dimensions is warranted.

BACK TO OUR PATIENT WITH A BICUSPID AORTIC VALVE

Our patient with a bicuspid aortic valve had a 4.6-cm root, an ascending aortic aneurysm, and several affected family members.

We would obtain dedicated aortic imaging at this patient’s initial visit with either gated CT with contrast or MRA, and we would obtain a cardioaortic surgery consult. We would repeat these studies at a follow-up visit 6 months later to detect any aortic growth compared with initial studies, and follow up annually thereafter. Echocardiography can also be done at the initial visit to determine if valvular disease is present that may influence clinical decisions.

Surgery would likely be recommended once the root reached a maximum area-to-height ratio greater than 10 cm2/m, or if the valve became severely dysfunctional during follow-up.

BACK TO OUR PATIENT WITH MARFAN SYNDROME

The young woman with Marfan syndrome has a 4.6-cm aortic root aneurysm and 2+ aortic insufficiency. Her question pertains to the threshold at which an operation would be considered. This question is complicated and is influenced by several concurrent clinical features in her presentation.

Starting with size criteria, patients with Marfan syndrome should be considered for elective aortic root repair at a diameter greater than 5 cm. However, an aortic cross-sectional area-to-height ratio greater than 10 cm2/m may provide a more robust metric for clinical decision-making than aortic diameter alone. Additional factors such as degree of aortic insufficiency and deleterious left ventricular remodeling may urge one to consider aortic root repair at a diameter of 4.5 cm.

These factors, including rate of growth and the surgeon’s assessment about his or her ability to preserve the aortic valve during repair, should be considered collectively in this scenario.

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