Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery

Abstract

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9 ± 2.6 post circulatory arrest to 3.4 ± 2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3 ± 3.5 mmol/L, intra-operatively, which normalized to 28.4 ± 2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25 ± 0.10, corrected to 7.43 ± 0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361 ± 104 and 253 ± 85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50 ± 35 minutes, respectively. The mean time required for systemic rewarming was 95 ± 66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.