Aortic Disease in Women

Educational Objectives

The goal of this program is to improve management of aortic disease in women. After hearing and assimilating this program, the clinician will be better able to:

1. Explain aortic structure and pathophysiology in relation to aortic aneurysms.
2. Cite differences in aneurysm between women and men.
3. List surgical considerations in aneurysm.

Summary

Aortic structure: it is composed of 3 layers; the inner layer is intima (an endothelium on connective tissue); the second layer is media (composed of smooth muscle cells, elastic fibers, collagen, and lamellar units with distinct fibromuscular layers); the outer layer is the adventitia (composed of fibroblast), which provides tension and strength to the aorta

Thoracic aortic aneurysm (TAA) vs abdominal aortic aneurysm (AAA): distinct pathology; TAA is more related to hypertension and hormone dysregulation; studies have shown that upregulating transforming growth factor-beta 1 (TGF-β1) causes complete disorganization of fibrolamellar units, which can lead to further connective tissue disorders (eg, Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome type IV, or familial TAA); AAA is mainly focused on atherosclerosis; excessive remodeling causes medial thinning or extracellular membrane fragmentation; increased inflammatory cytokines, lymphocyte infiltration, and degradation of the extracellular matrix; decreased smooth muscle cells, increased metalloprotease activity, and fragmentation; an initial cascade of genetic change or atherosclerotic accumulation usually leads to progression as the aorta begins to expand with smooth muscle cell degradation; risk factors (eg, smoking, infection, trauma, hypertension) can lead to rupture

Clinical perspective: true aneurysms involve all 3 layers of the arterial wall; ascending aneurysms arise anywhere from the aortic valve to the brachiocephalic trunk and account for ≈60% of aneurysms seen; aneurysms of the aortic arch can occur anywhere from the brachiocephalic trunk to the left subclavian artery and affect ≈10% of aneurysms; descending aortic aneurysms originate distal to the left subclavian artery; accounts for ≈40% of the population

Diagnosis and sizing for surgical evaluation: the cutoff sizes considered for surgical evaluation varies; for sinuses of Valsalva and women, >3 cm, for men >3.4 cm; for sinotubular junction, 2.6 to 3.2 cm for women and 2.9 to 3.6 cm for men are concerning; for ascending thoracic aorta, ≈2.7 cm for women and ≈3 cm for men are problematic; for proximal descending thoracic aorta, ≈1.9 cm for women and ≈2.1 cm for men warrant concern; for mid-descending thoracic aorta, 2.5 cm for women and 2.4 cm for men are cutoffs

2010 guidelines for thoracic aortic disease: published in the Journal of American College of Cardiology; the initial cut off for surgery with isolated ascending aortic aneurysms was >5.5 cm, growth rate of >0.5 cm in 1 yr, or have symptoms (eg, chest pain and compression-type symptoms such as cough, shortness of breath, voice changes); these patients should be referred to an aortic surgeon for further evaluation; additional considerations include coronary artery disease or valve pathology, which may warrant earlier referral to prevent rupture or dissection; patients with such pathology have different size criteria; for aneurysms of 3.5 to 4.4 cm or of 4.5 to 5.4 cm in patients already under evaluation, indication for operative repair remained 5.5 cm; for patients with new valve disease, repair is recommended at ≈4.5 cm; ascending aneurysms should be repaired in any patients undergoing surgery requiring opening of the chest for any other reason; criteria are 5.0 cm for patients with Marfan syndrome, 4.2 cm for patients with Loeys-Dietz syndrome, and 4.5 cm for bicuspid aortic valve

Aneurysm in men compared with women: current studies have been assessing changes in blood-flow velocity throughout aneurysm, and have shown a substantial difference between men and women; women are reported to have smaller diameter and larger maximum to normal diameter ratios than men; women have aneurysms with considerably more complex and dangerous blood flow than men; as a result, women have a 4 times higher rate of rupture of abdominal aortic aneurysm than men

Aortic aneurysm in women vs men: per Gao et al (2020), aorta in women are more saccular and forward facing, putting them at greater risk for rupture, whereas rupture in men is supported posteriorly by the lumbar vertebrae; women lack this support, and tend to rupture sooner, even at smaller sizes of aneurysm; there are differences in abdominal aortic aneurysm repair based on sex, and size and severity of aneurysm; in patients receiving elective repair, most are men and undergo endovascular repair

Surgical considerations: women tend to have shorter neck length and more angulation; based on current endovascular approaches, the more angulation or shorter the neck length a patient has, the less likely they are to have endovascular repair; patients who have undergone endovascular repair respond better in the long term and have fewer complications; ≈10% of patients with type A aortic dissections (occurring in the thoracic aorta [from the valve to the left subclavian artery]) and 40% of those with type B (occurring anywhere from the left subclavian artery down to the iliac arteries) survive at 1 yr; in-hospital mortality rates for patients with acute type A aortic dissections treated with surgery were found to be 26.6%, and 55.9% for those treated with medical therapy alone; even after surgical repairs, these patients face a significant mortality burden despite optimal medical management; female sex is also predictive of adverse events and higher in-hospital mortality rates; this could be related to delay in diagnosis related to nonclassic presentation, leading to delay in proper medical therapy and surgical treatment

Surgical treatment in women vs men: because of the anatomic differences between both sexes, women are less likely to be recommended surgical treatment, regardless of aneurysm size; women are also more likely to undergo open surgery over endovascular repair; patients undergoing open repair have lower survival rates than endovascular patients; women frequently have lower short-term (1 yr; 87% vs 90%) and long-term (10 yr; 28% vs 36%) survival rates; even after undergoing endovascular repair, women have risk-adjusted 10-yr survival rates that are 8% lower compared with men

Screening recommendations for women vs men: women are not recommended for routine screening for aneurysms, leading to presentation in extremis and poor overall survival; current US screening recommendations include an abdominal ultrasonography for men aged >65 yr who smoke; this is used to assess aortic diameter and has been shown to reduce aneurysm-related death by 50%; no indication or recommendation for ultrasonography screening for women because screening in women has not been shown to be cost-effective

Risk factors: women who smoke are at the highest risk for AAA; in women aged 75 yr who smoke, the risk for AAA is nearly 30 times higher compared with nonsmokers, men of the same age, and men who do not smoke; the highest risk for aneurysm is for men who are current smoker, followed by women who are current smokers; there is a substantial difference between current smokers in women who are aged ≥80 yr compared with women who have never smoked in the same age group; according to the speaker, this suggests it may not be cost-effective to screen all women aged >65, but perhaps to screen women aged >70 yr who smoke

Challenges: women have been found to be underrepresented in nearly all studies related to aortic disease; those of reproductive age were excluded to a greater extent from studies to limit exposure to experimental therapies that could affect fertility; most studies about aortic aneurysm repair, carotid revascularization, and lower-extremity revascularization have substantially underrepresented women

Readings

Boczar KE, Cheung K, Boodhwani M, et al. Sex differences in thoracic aortic aneurysm growth: Role of aortic stiffness. Hypertension. 2019; 73:190–196; Gao Z, Xiong J, Chen Z, et al. Gender differences of morphological and hemodynamic characteristics of abdominal aortic aneurysm. Biol Sex Differ 11, 41 (2020). https://doi.org/10.1186/s13293-020-00318-3; Hannawa KK, Eliason JL, Upchurch, Jr. GR. Gender differences in abdominal aortic aneurysms. Vascular. 2009 May–Jun; 17(Suppl 1):S30–S39; Isselbacher EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005; 111:816–828; Lo RC, Schermerhorn ML. Abdominal aortic aneurysms in women. J Vasc Surg. 2016 Mar; 63(3):839–844; Ramkumar N, Suckow BD, Arya S, et al. Association of sex with repair type and long-term mortality in adults with abdominal aortic aneurysm. JAMA Netw Open. 2020; 3(2):e1921240.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Klein was recorded at the 2022 Heart Health in Women Symposium, held virtually on February 5, 2022, and presented by the Virginia Commonwealth University School of Medicine. For information on future CME activities from this presenter, please visit medschool.vcu.edu. Audio Digest thanks the speakers and the Virginia Commonwealth University School of Medicine for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

AN641701

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.