Early and late outcome of operated and non-operated acute dissection of the descending aorta.

OBJECTIVE

At present debate continues concerning the optimal mode of treatment for type B dissections. Controversies are mainly due to discordant results regarding survival following medical or surgical treatment. We assessed early and long-term outcome of acute dissection of the descending aorta treated by emergency aortic replacement, medical treatment or delayed surgery.

METHODS

Between 1980 and 1995, 225 patients were hospitalized in the medical or surgical department of our institution with the diagnosis of acute type B aortic dissection. A total of 38 patients (16.8%) underwent replacement of the descending aorta within the first week after hospital admission. Primary indications for immediate surgery were: rupturing aneurysm (n = 15), diameter of the descending aorta (n = 13), malperfusion of the thoracoabdominal aorta (n = 8) and pseudocoarctation syndrome with uncontrollable hypertension (n = 2). All other patients (n = 187) underwent primary conservative treatment on the intensive care unit, including appropriate anti-hypertensive medication. In 12 of them, surgery was denied because of age or significant concomitant diseases.

RESULTS

Hospital mortality after urgent or emergency surgery was 21% (8/38 patients) for the overall time period. There has been a significant decrease in hospital mortality during the last 5 year-period (12% versus 30% between 1980 and 1994). Causes of death were: cardiac failure in 3, bleeding complications in 2, postoperative mesenteric ischemia in 2 and septicemia in one patient. From the 30 operative survivors, 9 (30%) patients required further surgery on the native aorta after a mean follow-up of 48 +/- 13 months. Hospital mortality during conservative treatment was 17.6% (33/187 patients). Main causes of death were rupture in 14, thoraco-abdominal malperfusion in 13 and cardiac failure in 3 patients, whereas in 3 patients, the cause of death could not be evaluated. In this group, 9 patients had to be shifted to early surgery during the initial hospitalization because of impending rupture (n = 4), rapidly increasing diameter (n = 2) and suspicion of intestinal ischemia (n = 3). After hospital discharge, surgery for chronic dissection was performed in 47 patients, mainly because of expanding descending aortic aneurysm. Hospital mortality was 8% (4/47 patients). Actuarial survival rates after surgery during the first admission were 85 +/- 6% at 5 years and 61 +/- 8% at 10 years, versus 76 +/- 5 and 50 +/- 7% respectively, following conservative treatment (P < 0.001).

CONCLUSION

Nowadays, acute type B dissection can be treated surgically with a reasonable perioperative risk. Despite aggressive anti-hypertensive treatment, hospital mortality of primary conservative treatment is still high and a substantial percentage of patients requires surgery during initial hospitalization. Main causes of death in both groups are rupture and abdominal malperfusion: therefore, closed clinical and radiologic assessment of the whole thoraco-abdominal aorta is of utmost importance. Long-term results are satisfying; unlimited radiographic follow-up allows for detection of potential severe complications and for proper planning of elective reoperations when indicated.