To assess the safety of high-moderate (24.1-28.0°C) and low-moderate (20.1-24.0°C) systemic hypothermia (MHCA) during circulatory arrest in patients with acute DeBakey I aortic dissection (DeBakey I AAD), particularly concerning spinal cord protection. Between 2009 and 2020, 1759 patients with DeBakey I AAD who underwent frozen elephant trunk and total arch replacement surgery at a tertiary center were divided into preoperative malperfusion (viscera, spinal cord, or lower extremities) and non-malperfusion subgroups. The baseline differences were balanced using propensity score matching. Prognoses were compared between those who were subjected to high-MHCA (nasopharyngeal temperature, 24.1-28.0°C) and low-MHCA (20.1-24.0°C). In the non-malperfusion subgroup (n=1389), 469 pairs of matched patients showed lower in-hospital mortality and incidence of acute kidney injury in the high-MHCA group than in the low-MHCA group (in-hospital mortality, 7.0% vs. 10.2%, P=0.01; acute kidney injury, 57.1% vs. 64.6%, P<0.01). The duration of mechanical ventilation was shorter in the high-MHCA group than that in the low-MHCA group (P=0.03). No significant difference in the incidence of paraplegia was observed between the two groups. In the malperfusion subgroup (n=370), 112 pairs of matched patients showed a higher incidence of paraplegia in the high-MHCA group than in the low-MHCA group (15.9% vs. 6.5%, P=0.04). The safety of high-MHCA, a commonly used temperature management strategy during aortic arch surgery, was recognized in most patients with DeBakey I AAD. However, among patients with preoperative distal organ malperfusion, low-MHCA may be more appropriate because of an increased risk of postoperative paraplegia associated with high-MHCA.