Diffusion-weighted magnetic resonance imaging lesions after repair of acute type A aortic dissection: association with neurocognitive outcomes†‡.

OBJECTIVES: We sought to analyse the preoperative status of arch vessels by postoperative diffusion-weighted magnetic resonance imaging (DWI) as a potential surrogate marker for cerebral thromboembolism and its relationship to neurocognitive outcomes. METHODS: Preoperative computed tomography (CT) and postoperative DWI were available for 50 patients who received surgery for acute type A aortic dissection. Two radiologists evaluated CT and DWI scans. Mini-mental status examinations (MMSE) were performed on the same day with DWI. RESULTS: Mean age of participants was 57 ± 14 years. MMSE and DWI were performed 6 ± 3 days after surgery. New cerebral embolisms were evident in 35 of 50 patients (70%) and often occurred as multiple lesions (28/35, 80%; range 2-21). Among patients with multiple lesions, 23 (66%) were clinically silent. Pathological lesions at the origin of the arch vessels correlated with the number and volume of new DWI lesions (P < 0.05). Degree of neurocognitive dysfunction tested by MMSE was negatively associated with age (r = -0.48, P < 0.0001) and left-sided DWI lesion number and volume (r = -0.74, P < 0.0001; r = -0.707, P < 0.0001). CONCLUSIONS: DWI revealed new cerebral embolisms in 70% of patients following surgery for acute type A aortic dissection. Lesion number and volume significantly correlated with pathological status of arch vessels. MMSE was representative of left-sided lesions.

Effects of intermittent lower body perfusion on end-organ function during repair of acute DeBakey type I aortic dissection under moderate hypothermic circulatory arrest.

OBJECTIVES: To avoid deep hypothermia-related side effects, moderate hypothermic circulatory arrest (HCA) is commonly employed during aortic arch repair, thereby jeopardizing end-organ protection. We sought to analyse the effect of intermittent lower body perfusion (ILBP) on end-organ function during repair of acute DeBakey type I aortic dissection (AIAD). METHODS: Between May 2008 and May 2011, 107 patients underwent surgical repair for AIAD. All operations were performed with selective cerebral perfusion (SCP) under either moderate HCA only (n = 57) or moderate HCA with ILBP (n = 50). Adverse outcomes, including operative mortality, permanent neurological deficit, temporary neurological deficit, renal failure requiring dialysis and hepatic dysfunction, were compared between the two groups. RESULTS: The mean body temperature at the initiation of SCP was 28.7 ± 1.9 °C. Overall operative mortality occurred in 6 (5.6%) patients. The incidences of permanent neurological deficit and temporary neurological deficit were 1.9 and 4.7%, respectively. None of the 9 (8.4%) patients who suffered postoperative renal failure requiring dialysis received ILBP. The laboratory data showed significantly lower levels of hepatic and kidney enzymes in the ILBP group (P < 0.05). CONCLUSIONS: Significantly lower levels of hepatic and kidney enzymes indicate more effective end-organ protection with the use of ILBP. Our data suggest that ILBP provides more effective end-organ protection during repair of aortic arch under moderate HCA.