Preoperative Hematocrit Is Not Associated With Stroke After Surgery for Acute Type A Aortic Dissection

To determine the impact of hematocrit on adverse neurologic events after acute type A aortic dissection (ATAAD) repair under deep hypothermic circulatory arrest.

Retrospective study of consecutive aortic surgeries from 2010 to 2021.

Single institution.

Patients undergoing open ATAAD repairs, excluding those with preoperative cerebral malperfusion syndrome (defined as neurologic deficit with radiographic evidence of cerebral branch vessel malperfusion).

Patients were split into three groups: normal, low, and high hematocrit.

A total of 527 patients were included, of which 355 (67.3%) had normal hematocrit, 143 (27.1%) had low hematocrit, and 29 (5.5%) had high hematocrit. Overall, 20 (3.8%) patients had a postoperative stroke, which was comparable across groups (p = 0.59). Patients with normal hematocrit had lower in-hospital mortality (p = 0.02) and lower transfusion rates (p < 0.001), while re-exploration for bleeding was similar across groups (p = 0.68). After multivariable adjustment, there was no association between hematocrit and postoperative stroke (odds ratio [OR]: 1.00, 95% confidence interval [CI]: 0.99, 1.00, p = 0.79). Compared with normal hematocrit, there was no association between low hematocrit (OR: 1.59, 95% CI: 0.77, 3.28, p = 0.21) or high hematocrit (OR: 2.48, 95% CI: 0.74, 8.29, p = 0.14) and in-hospital mortality.

Preoperative hematocrit was not associated with stroke or mortality after ATAAD repair. The rheologic effect of hematocrit on cerebral perfusion under deep hypothermia may be minimal.