Cerebral perfusion issues in acute type A aortic dissection without preoperative malperfusion: how do surgical factors affect outcomes?

Objectives: Both preoperative (disease-related) and operative (management-related) variables make the assessment of the outcomes of acute type A aortic dissection (ATAAD) surgery a difficult task. Our aim was to evaluate the impact of operative factors, including arterial cannulation site, route of cerebral perfusion and surgeon's specific experience with ATAAD ('aortic surgeon'), on the early results of surgical management, with particular attention to neurological injury.

Methods: Penn classification was used to identify clinically homogeneous risk groups of ATAAD patients undergoing surgery. Between January 2007 and June 2014, 111 of 183 ATAAD patients treated with open surgery in a single centre were in Penn Class Aa (no ischaemic complications at presentation). They were divided in two groups depending on the arterial cannulation site: femoral artery (FemA; 56 patients) or right axillary artery (RAxA; 55 patients). Study outcomes included: 30-day mortality, major adverse cardiac and cerebrovascular events at 30 days, neurological complications and in particular, patterns of stroke as defined by Bamford classification.

Results: No significant differences in preoperative variables were observed between cannulation-site groups, except for myocardial ischaemic time (60.9 ± 30.4 min in the RAxA group vs 81.7 ± 52.3 in the FemA group, P = 0.014) and cerebral perfusion time (42.1 ± 25.5 min in the RAxA group vs 52.9 ± 32.6 in the FemA group, P = 0.048). Outcomes in terms of mortality and neurological injury did not differ except for a higher incidence of lacunar cerebral infarction (LACI) in the RAxA group (14.5 vs 3.6%, P = 0.043), mainly but not exclusively explained by a higher incidence of LACI in unilateral (17.2%) than in bilateral cerebral perfusion (6.9%) within the RAxA group. The 'non-aortic surgeon' was associated instead with 30-day mortality and composite outcome in multivariable analysis (respectively, OR 6.40, P = 0.002 and OR 4.68, P = 0.001).

Conclusions: The RAxA cannulation and FemA cannulation are associated with comparable 30-day mortality following surgery for aortic dissection. However, the possible higher risk of LACI-type strokes in the RAxA group, especially when associated with unilateral brain perfusion, should be considered when RAxA cannulation is performed in ATAAD. The hypothesis that more experienced surgeons may produce better earlier outcomes warrants further investigation.