Effect of lower-body ischemia duration in aortic arch surgery under mild-to-moderate hypothermic circulatory arrest

Abstract

Objectives

Aortic arch surgery is performed at increasingly higher circulatory arrest temperatures. This might affect visceral protection. We analyzed the effect of visceral ischemic time in arch surgery under mild-to-moderate hypothermia.

Methods

We divided the population into 3 groups: group 1 (visceral ischemic time ≤30 minutes), group 2 (31-60 minutes), and group 3 (>60 minutes). The link between visceral ischemic times and in-hospital outcomes, and visceral function biomarker levels were retrospectively analyzed through chi-square test, nonparametric analysis of variance, and cubic spline interpolation.

Results

From 1995 to 2023, 1325 patients underwent aortic arch surgery under circulatory arrest at our center. Mild-to-moderate hypothermia (nasopharyngeal temperature ≥25°) was used in 960 cases. There was no significant difference among the groups for in-hospital death (group 1 = 8.5%, group 2 = 13.2%, group 3 = 11.3%; P = .224), renal complications (group 1 = 13.0%, group 2 = 19.7%, group 3 = 22.6%; P = .056), and gastrointestinal complications (group 1 = 5%, group 2 = 5.5%, group 3 = 7.1%; P = .696). However, respiratory complications (group 1 = 19.4%, group 2 = 28.1%, group 3 = 21.4%; P = .027) and transient dialysis (group 1 = 2.8%, group 2 = 7.8%, group 3 = 11.3%; P = .011) were linked to longer visceral ischemic times. Groups 2 and 3 presented significantly higher levels of creatinine (P < .01), glutamic-oxaloacetic transaminase (P < .05), and glutamic pyruvic transaminase (24 and 48 hours postsurgery, P < .01). Cubic spline analysis showed that the incidence of renal complications reached a minimum at a low visceral ischemic time and then consistently increased. Respiratory complications showed a maximum incidence at approximately 50 minutes of visceral ischemic time and then subsequently decreased.

Conclusions

Mild-to-moderate hypothermia is a safe strategy for visceral organ protection regardless of visceral ischemic time. However, longer visceral ischemic times are linked to renal complications.