Hemiarch Replacement with mild hypothermia at 30℃ for Acute Type A Aortic Dissection

Although hypothermic circulatory arrest combined with selective cerebral perfusion is a safe strategy, the optimal temperature of hypothermia has not been clearly determined. We verify safety of mild hypothermia for hemiarch replacement (HAR) of acute type A aortic dissection (AAAD).

This was a single-center, retrospective, cohort study between April 2011 and March 2017. A total of 86 patients underwent HAR of AAAD (mean age, 73.3±9.6 years; 27 male and 58 female). Moderate hypothermia (28℃; group A) was performed in 18 patients and mild hypothermia (30℃; group B) was performed in 67 patients.

No significant differences were found between group A and B with preoperative factor (coronary risk factor, renal dysfunction, atrial fibrillation, asthma and chronic obstructive pulmonary). The mean durations of cardiopulmonary bypass time accounted for 178 ± 53 min in group A and 172 ± 52 min in group B (p = 0.693). Aortic clamp time were 118 ± 37 min in group A and 116 ± 52 min in group B (p = 0.789). Circulatory arrest time were 42 ± 9 min in group A and 50 ± 11 min in group B (p = 0.005). Intraoperative bleeding was significantly different between 1925 ± 770 ml in group A and 1471 ± 846 ml in group B (p = 0.043). Postoperative permanent neurologic dysfunction occurred in none of group A and 1.5% (1 of 67) in group B (p = 1.000). Postoperative transient neurologic dysfunction occurred in 5.6% (1 of 18) in group A and 4.5% (3 of 67) in group B (p = 1.000). Thirty-day mortality was 5.6% (1 of 18) in group A and 7.5% (5 of 67) in group B (p = 0.348).

Mild hypothermia was safely applied to HAR of AAAD and is associated without postoperative neurological deficit.