Experience with the conventional and frozen elephant trunk techniques: a single-centre study

Abstract

The treatment of patients with extensive thoracic aortic disease involving the arch and descending/thoracoabdominal aorta is often performed using an elephant trunk procedure. We retrospectively analysed our results comparing two different techniques: the conventional elephant trunk (cET) and the frozen elephant trunk (FET) operation. Between January 2003 and December 2011, 171 consecutive patients underwent total aortic arch replacement with either a cET (n = 125) or FET (n = 46) technique. The mean age was 64 ± 13 years and was significantly higher in the FET group (P < 0.01). Acute Type A aortic dissection was the indication for surgery in 53.6% of cET and 17.4% of FET patients, and degenerative or atherosclerotic aneurysm accounted for 33.6% of cET and 58.7% of FET patients. The remaining patients were operated on for chronic Type A or acute or chronic Type B dissections with arch involvement. In-hospital mortality was 21.6 vs 8.7% for cET and FET patients, respectively (P = 0.1). Logistic regression analysis revealed Type A aortic dissection (odds ratio (OR) 3.1, P = 0.01) as the only independent predictor of hospital mortality. Stroke occurred in 16 vs 13% of cET vs FET patients (P = 0.4). Type A aortic dissection was an independent predictor of stroke by multivariable analysis (OR 2.6, P = 0.03), and axillary arterial cannulation was protective against stroke (OR 0.4, P = 0.04). The occurrence of new-onset paraplegia was significantly higher in the FET group (21.7 vs 4.0%, P < 0.001), and aortic repair with the FET technique was an independent predictor for paraplegia (OR 6.6, P = 0.001). Among patients receiving FET, a body core temperature during circulatory arrest of ≥ 28 °C in combination with a prolonged circulatory arrest time of >40 min was an independent predictor for permanent spinal cord injury (OR 5.0, 95% CI 1.1-20, P = 0.038). The estimated 1-, 3- and 5-year survival were 70 ± 4, 70 ± 4 and 68 ± 4% (cET) and 4 ± 7 and 60 ± 9, 40 ± 1% (FET), with mean survival time 5.2 ± 0.3 vs 3.8 ± 0.5 years (cET vs FET, log-rank P = 0.9). The FET procedure for extensive thoracic aortic disease is associated with an acceptable mortality rate, but with a higher incidence of perioperative spinal cord injury than cET. Arch replacement with a cET technique should be strongly considered in patients with expected prolonged circulatory arrest times, particularly if operated on under mild or moderate hypothermia. Axillary cannulation is associated with superior neurological outcomes and Type A acute aortic dissection is a risk factor for mortality and poor neurological outcomes in this patient population.