Brain-protective strategies for acute type A aortic dissection (TAAD) remain controversial. Moderate hypothermia circulatory arrest (MHCA) without cerebral perfusion is not commonly used. However, we aimed to assess its safety and efficacy in 358 patients who underwent hemiarch replacement with MHCA for acute type A aortic dissection at our institution from August 2012 to August 2022.

Clinical outcomes were compared according to circulatory arrest time [≤15 min (S group, n = 52) vs ≥16 min (L group, n = 306)]. The primary outcome was postoperative stroke.

The S group had more older patients (72.5 vs 68.8 years; P = 0.04), a greater incidence of carotid artery malperfusion (21% vs 11%; P = 0.043) and a lower body mass index (21.7 vs 23.6 kg/m²; P < 0.01) and hemodynamic instability (3.8% vs 16%; P = 0.02) than the L group. The incidence of postoperative stroke (7.7% vs 12%; P = 0.33) and the rate of 30-day mortality (5.8% vs 6.5%; P = 0.83) did not significantly differ between groups. After adjusting for all potential confounding factors pre- and intraoperatively, there was no significant difference in postoperative outcomes between groups.

MHCA alone for TAAD had comparable postoperative outcomes with circulatory arrest times under and over 15 min. However, longer arrest times were associated with a higher risk of stroke.