My husband has a 4.2 cm ascending thoracic aortic aneurysm. is it best to consult with a vascular surgeon or a cardiologist?

Aneurysm: Either of those specialists would be appropriate. At 4.2cm there is some time likely before the aorta would likely need surgery so either would be ok.

Close monitoring: Indications for surgical intervention are: symptomatic, larger than 5.5 cm, growth rate of greater than 0.5 cm in 6 months, or if you developed aortic valve disease ("leaky valve" or stenotic valve) or if greater than 5 cm and having open heart procedure for another reason. It sounds like you do not meet the criteria at this time but close monitoring is required. Ct and echo should be done.

Cardiac surgeon: Ascending aortic aneurysms are treated by cardiothoracic surgeons. But a vascular surgeon may be involved if the aneurysm involves the abdominal aorta. Your husband may need to see the cardiologist for his coronary arteries as well. The rate of growth of his aneurysm will need to be followed and a detailed family history.

Cardiothoracic: Sometimes the ascending and descending aorta are involved and collaboration of specialties is required. At 4.2 regular follow up with ct at 6 months is suggested. An echo of the heart with the aortic valve is a good baseline. If there is family history of marfan' s or other aneurysms you may want children evaluated early.

This represents mild: Enlargement and can be followed by echo, ct or MRI depending upon location...Any cardiovascular specialist can keep tabs on it...Generally this is a long way from requiring surgical intervention.

Cardio thoracic : Actually, your husband will need to see a cardiac surgeon. Vascular surgeons deal with descending thoracic aneurysms. Due to the close proximity of the ascending aneurysm and the heart, many times surgical repair requires cardio pulmonary bypass. Usually ascending aneurysms are not repaired until 6cm. It is likely that routine ct scan surveillance at yearly intervals will be recommended.