Ascending Aortic Aneurysm Referral
Ascending aortic aneurysms require referral to cardiothoracic (cardiac) surgery, not vascular surgery. Cardiothoracic surgeons specialize in operations on the heart and great vessels within the chest cavity, including the ascending aorta, aortic root, and aortic arch, whereas vascular surgeons primarily manage peripheral arterial disease and descending/abdominal aortic pathology 1, 2.
Surgical Specialty Distinction
Cardiothoracic surgery manages all ascending aortic pathology because these operations require cardiopulmonary bypass, aortic cross-clamping, and often concomitant aortic valve procedures or coronary artery bypass grafting 1.
The ascending aorta extends from the aortic valve to the innominate artery origin, and surgical repair frequently involves composite valve-graft replacement, valve-sparing root remodeling, or supracoronary graft replacement—all procedures within the cardiac surgery domain 1, 3.
Vascular surgeons typically handle descending thoracic aortic aneurysms (via open repair or thoracic endovascular aortic repair [TEVAR]) and abdominal aortic aneurysms, but not the ascending aorta or aortic root 1.
Referral Thresholds for Cardiothoracic Surgery
For patients without genetic conditions or bicuspid aortic valve:
Refer when the ascending aortic diameter reaches ≥5.5 cm in asymptomatic patients, as the risk of dissection or rupture exceeds operative mortality at experienced centers 1, 2.
At experienced multidisciplinary aortic centers with surgical mortality <5%, referral at ≥5.0 cm is reasonable to allow preoperative optimization and surgical planning 2, 4.
For patients with genetic aortopathies:
Marfan syndrome: Refer at ≥5.0 cm (Class I indication), or at ≥4.5 cm if additional risk factors are present (family history of dissection, aortic regurgitation, growth >0.3 cm/year, or planned pregnancy) 1, 2.
Loeys-Dietz syndrome: Refer at 4.2–4.6 cm due to extremely high dissection risk at smaller diameters (mean age of death 26 years if untreated) 2, 3.
Bicuspid aortic valve with risk factors: Refer at ≥5.0 cm when coarctation, systemic hypertension, family history of dissection, or rapid growth (>0.3 cm/year) is present 1, 2.
Growth-rate triggers (independent of absolute diameter):
- Refer immediately if growth is ≥0.5 cm in 1 year or ≥0.3 cm/year sustained over 2 consecutive years, as this exceeds typical degenerative growth rates (0.1–0.2 cm/year) and signals high risk 5, 2, 6, 7.
Concomitant cardiac surgery:
- When a patient requires aortic valve repair/replacement, refer for concomitant ascending aortic replacement if the diameter is ≥4.5 cm, as the incremental risk is minimal when the chest is already open 1, 2, 4.
Urgent Referral Indications
Any symptoms attributable to the aneurysm (chest pain, back pain, hoarseness, dysphagia, dyspnea) mandate immediate cardiothoracic surgery consultation regardless of diameter, as symptoms suggest impending rupture or rapid expansion 5, 2, 4.
Approximately 60% of acute type A aortic dissections occur at diameters <5.5 cm, underscoring that diameter alone is an imperfect predictor and that symptomatic patients require urgent evaluation 5, 2.
Common Pitfalls to Avoid
Do not refer to vascular surgery for ascending aortic pathology, as this is outside their scope of practice and will result in delayed care and re-referral to cardiothoracic surgery 1.
Do not delay referral until the patient becomes symptomatic or the aneurysm reaches 6.0 cm, as the median size at rupture or dissection is 5.9–6.0 cm for ascending aneurysms, meaning half of patients will suffer catastrophic complications before reaching this threshold 6, 7, 8.
Do not use inconsistent imaging modalities for serial surveillance, as CT/MRI measurements are typically 1–2 mm larger than echocardiographic measurements, which can falsely suggest rapid growth 2.
For patients at extremes of height, calculate the aortic area/height ratio (surgery reasonable at ≥10 cm²/m) or Aortic Height Index (AHI = diameter/height; surgery reasonable at ≥3.21 cm/m), as absolute diameter thresholds may be inappropriate for very tall or short patients 5, 2, 4.
Multidisciplinary Aortic Team Approach
Optimal management occurs at centers with dedicated Multidisciplinary Aortic Teams comprising cardiothoracic surgeons, cardiologists, cardiac anesthesiologists, and genetic counselors, as these teams achieve lower operative mortality (<5% for elective ascending aortic surgery) 2, 4.
Verify that the referral center has low surgical mortality rates before applying lower intervention thresholds (e.g., 5.0 cm), as higher-volume centers achieve superior outcomes 4.