Effective Treatments for Thoracic Aortic Aneurysms: A prospective cohort study (ETTAA)

The aorta is the main artery that carries oxygen-rich blood from the heart to the body. An aneurysm is a swelling or bulging in a blood vessel, which usually occurs where the wall has become weak and has lost its elastic properties, so it doesn’t return to its normal shape after the blood has passed through. A thoracic aortic aneurysm, or TAA for short, is an aneurysm in the section of the aorta in the chest [https://www.bhf.org.uk/informationsupport/conditions/thoracic-aortic-aneurysms] The ETTAA study aimed to investigate aneurysm growth rates, patient outcomes, quality of life and costs, including those from surgery. Surgical treatments include Open Heart Surgery, where the section of the aorta that contains the aneurysm is removed and replaced by a new aorta made from a synthetic material, and Stent Grafting, where tubes are inserted into arteries to allow blood to flow freely, using less invasive “keyhole” surgery. The existing research evidence was reviewed but data comparing the effectiveness of these two approaches was of sparse or limited quality, and outdated. Between 2014 and 2018, clinical experts were surveyed and 886 NHS patients with Chronic TAAs (≥4cm diameter) were observed to monitor aneurysm growth and patient outcomes. If patients were unfit or unwilling to have surgery, they had Conservative Management with medication and lifestyle changes. For small aneurysms, experts recommended Watchful Waiting, with regular monitoring, until the aneurysm grew to about 6cm in diameter. Open Surgery was preferred for larger arch aneurysms and for descending aneurysms in patients with genetic disorders. Otherwise Stent Grafting was preferred. The observational study recruited 321 women and 565 men from 30 English hospitals, average age 71 years. 489 patients underwent Watchful Waiting and 112 Conservative Management. Without surgery death rates were higher for women and older patients, while risk of dying doubled for each centimetre of aneurysm diameter at baseline. 150 patients had Stent Grafting and 135 had Open Surgery. One-year overall survival was 83% after Stent Grafting and 79% after Open Surgery but the difference could be due to chance. Factors affecting survival after stent grafting or open surgery were aneurysm location, age, breathlessness and time waiting for a procedure. Small aneurysms were at low risk, so that blood pressure management and smoking cessation are recommended. For larger aneurysms, it is important that surgery is not delayed, since longer waiting time to surgery meant outcomes were poorer. Only about half of patients who had surgery were considered suitable for both Stent Grafting and Open Surgery which limited ability to determine the best use of NHS resources. No comparative cost-effectiveness analysis was feasible. The main cost to an ESG procedure was the sent graft, and the main cost to an OSR procedure was ITU days.