Lactate as a Preoperative Predictor of Mortality in Patients Undergoing Emergency Type A Aortic Dissection Repair.

Aortic dissection is a life-threatening condition where emergent surgical repair is the standard of care. However, despite operative intervention, mortality is 10-15% in all patients. Objective markers to distinguish when surgical repair is more beneficial versus being futile are warranted. Currently, no such known measures are widely agreed upon. Since most complications from aortic dissection stem from malperfusion, serum lactate is thought to be a surrogate marker for malperfusion. This scoping review aims to examine the preoperative predictive value of lactate or lactate dehydrogenase (LDH) in assessing postoperative mortality in patients undergoing surgical repair for acute Stanford Type A aortic dissection (ATAAD). PubMed was searched for the following search terms: "Dissection, Ascending Aorta", "Dissection, Thoracic Aorta", or "Aortic Dissection". Prospective and retrospective randomized controlled trials, case reports, and cohort studies were included in the initial search. Studies were first screened for inclusion of preoperative lactate or LDH level with a search of "lac" or "LDH". Included studies consisted of patients aged 18 or older diagnosed with Stanford Type A/Debakey Type I and II aortic dissection with reported preoperative lactate or LDH levels and postoperative mortality treated within 14 days of symptom onset. Preoperative laboratory values were measured from samples collected prior to patient transfer to the operating room or before utilization of ECMO intraoperatively. A comprehensive database search identified a total of 4722 articles. After a rigid screening process, 46 studies fit the inclusion criteria. These papers reported a combined 4696 participants with either preoperative lactate or LDH levels and postoperative mortality. The mean preoperative lactate level was 2.4 mmol/L, whereas the LDH level was 424.9 U/L. Postoperative mortality was 16.51%. Average creatinine, BUN, platelets, INR, PT, PTT, and hemoglobin were all within normal lab analysis limits. Neither lactate nor LDH should be used as a solo predictor of postoperative mortality after ATAAD due to lack of consensus on the cut-off values. Accompanying clinical signs, lab abnormalities, and radiographic findings taken together may be better predictors of prognosis.