Early Surgery versus Conservative Management of Dissecting Aneurysms of the Descending Thoracic Aorta

Background. Optimal management for patients who present acutely with uncomplicated type III dissections of the descending thoracic aorta remains controversial. Patients with dissecting aneurysms represent a subgroup at high risk of rupture who may benefit from early elective surgery as an alternative to standard medical therapy. Methods. The authors constructed a Markov decision model to compare the following clinical strategies: 1) early elective surgery immediately after diagnosis (EARLY SURGERY), 2) medical therapy with periodic computed tomography and with elective surgery when aortic diameter is projected to reach 6 cm (CT FOLLOW-UP), and 3) medical therapy with urgent surgery for dissection-related complications (WATCHFUL WAITING). Data sources included Medline (1966-1995) and a case series of patients with type III dissecting aneurysms who received medical therapy with radiographic follow-up. Results. For a typical 60-year-old patient with an acute, uncomplicated 5-cm dissecting aneurysm of the descending thoracic aorta and an operative 30-day mortality rate of 14% for EARLY SURGERY, the model predicts that EARLY SURGERY improves survival compared with CT FOLLOW-UP (9.91 vs 9.44 QALYs). Conservative management may be preferred for patients who have maximum aneurysm diameters ≤4 cm, are elderly (≥75 years), or have higher-than-expected risk of operative mortality. Conclusions. The choice between early surgery and medical therapy for uncomplicated dissecting aneurysm of the descending thoracic aorta should be tailored to the individual patient's operative risk, risk of dissection-related events, and age. Early surgery may be a reasonable alternative to medical therapy for carefully selected patients at centers with favorable perioperative mortality rates. Key words: thoracic aorta; dissecting aneurysm ; decision support techniques. (Med Decis Making 2000;20:377-393)