Late dissection of the ascending aorta after previous cardiac surgery: risk, presentation and outcome.

OBJECTIVE: Aortic dissection is a potentially life-threatening condition and may follow surgical interventions as a complication with distinct presentation and high mortality. Information on the incidence and etiology of aortic dissections following cardiac surgery is sparse and inconsistent. The true incidence of this entity may so far have been underestimated.
METHODS: Data of 223 operations on the thoracic aorta performed exclusively at our institution between January 1990 and May 2001 were analysed for clinical and prognostic features. Patients with Marfan syndrome and traumatic cases were not included. Cases of type A aortic dissection following cardiac surgery were investigated further.
RESULTS: Dissection of the ascending aorta occurred in 83 patients, of whom 11 (13.2%, six acute and five chronic) had undergone previous cardiac surgery (four aortic valve replacements (AVR), two double valve replacements (DVR), two AVR+coronary artery bypass grafts (CABG), three CABGs). The time interval between first operation and dissection was 0.2-17 years (median 3.3 years). Eight (72%) patients had arterial hypertension. The aortic diameter was >or=50mm in all 11 cases upon presentation. Dissections were treated with Bentall procedures (3), Cabrol procedure (1), supracoronary tube graft (6) including concomitant CABG (3) and AVR with local repair (1). Total in-hospital mortality was 54% (6/11), and 66% (4/6) in cases with acute dissection due to low cardiac output (3) and myocardial infarction (3).
CONCLUSIONS: Type-A aortic dissection can follow cardiac operations at any time with no typical interval or associated histology and with high overall hospital mortality. Male patients with arterial hypertension are at increased risk. Clinical presentation may differ from primary dissection with implications for management and risk estimation.