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Risk factors for acute kidney injury in aortic arch surgery with selective cerebral perfusion and mild hypothermic lower body circulatory arrest.

OBJECTIVES
Previous studies have reported a high incidence of acute kidney injury (AKI) after thoracic aortic surgery. However, the incidence of AKI in patients undergoing total arch replacement (TAR) with selective cerebral perfusion (SCP) and mild hypothermic lower body circulatory arrest (mild HLBCA) with a tympanic temperature of 25°C remains unknown. We studied AKI incidence and associated risk factors, as defined by the Acute Kidney Injury Network (AKIN).


METHODS
We examined 116 consecutive patients with aortic arch aneurysm undergoing non-emergency TAR. Our surgical method is standardized to use systemic cooling of the tympanic membrane temperature to 25°C for circulatory arrest, followed by SCP and myocardial protection by cold blood cardioplegia. Anastomoses were sequentially constructed at the distal arch, the proximal root, the left sub-clavian artery, the left carotid artery and the right brachiocephalic artery. Bladder temperature was generally around 30°C at the start of lower body circulatory arrest (mild HLBCA) until reperfusion of the distal aorta. The incidence of AKI was investigated, with multivariate analysis of its risk factors.


RESULTS
The mean operation time, cardiopulmonary bypass (CPB) time, mild HLBCA time and SCP time were 270.6 ± 72.5, 151.0 ± 46.4, 53.1 ± 20.1 and 99.0 ± 28.4 min, respectively. Hospital mortality occurred in 2 cases (1.7%). AKI occurred in 50 cases (43.1%); of which, 2 cases required renal replacement therapy (RRT). However, AKI had subsided in 44 cases by discharge. For contemporary perspective, the incidence of AKI was 32.8% in off-pump coronary bypass grafting and 38.9% in aortic valve replacement. Multivariate analysis of risk factors for AKI identified chronic kidney disease (CKD) (eGFR <60 ml/min/1.73 m(2)) and mild HLBCA time >60 min.


CONCLUSIONS
Our method of TAR was associated with low mortality and low rate of kidney injury by discharge. However, prolonged mild HLBCA and preoperative CKD might need additional consideration.