Blood lactate predicts mortality after surgical repair of type A acute aortic dissection

Ischemia and malperfusion are strong predictors of poor postoperative outcomes in type A acute aortic dissection (TAAAD). Serum lactate is an accurate surrogate point-of-care marker of malperfusion. The aim of this study is to investigate the correlation between lactate, in-hospital outcomes, and 1-year survival following TAAAD repair.

One hundred and thirty-two patients underwent operative repair of TAAAD over a 4-year period at our institution 128 patients had serum lactate measurements at three stages peri-operatively-preoperatively, at the end of cardiopulmonary bypass (post-CPB) and 6 h postintensive care unit (ICU) admission. The primary outcomes were in-hospital mortality and 1-year survival. The secondary outcomes were the incidences of in-hospital morbidities.

Patients were divided into two groups: 88 (68.8%) with normal lactate and 40 (31.2%) with elevated lactate (>2.2 mmol/L). Lactate measured preoperatively (odds ratio 1.52, 95% confidence interval 1.17-2.07, p < .01), post-CPB (1.34, 1.14-1.64, p < .01) and 6 h post-ICU admission (1.29, 1.08-1.55, p < .01) was an independent predictor of in-hospital mortality. Following adjustment for the Penn Classification, lactate continued to have a significant correlation with in-hospital mortality at all three timepoints. There was a higher incidence of complications in the elevated lactate group and especially hemofiltration (20% vs. 9.1%, p = .08). 1-year survival was similar in both groups (p = .23).

There is a direct correlation between elevated serum lactate and postoperative mortality after TAAAD repair, which is independent of the Penn Classification status on admission.