Modulation of aldosterone release by epidural analgesia impacts brain natriuretic peptide: a link to stress cardiomyopathy? Pilot study.

OBJECTIVE: Data pertaining to whether stress-induced aldosterone release is associated with cardiac disorders are lacking. This study was designed to compare whether the modulation of intra-operative aldosterone release by epidural analgesia had an effect on the brain natriuretic peptide (BNP) levels. DESIGN, PATIENTS, MEASUREMENTS: A study was pilot prospective, open label randomized one. Patients were randomized to one of two anaesthesia protocols: group 1 included 13 patients who received general anaesthesia, and group 2 included 12 patients who received combined general anaesthesia and epidural analgesia. Study protocol was by completed 25 male patients, median age 56 years, without significant comorbidities, who underwent radical cystectomy because of urinary bladder tumour. Serum aldosterone, BNP, cortisol (measured by radioimmunoassay), adrenocorticotropine hormone (ACTH) (by solid-phase ELSA), blood chemistry, complete blood count and vital signs were compared preoperatively, intra-operatively and at postoperative days (POD) 1 and 7. RESULTS: Hemodynamics was stable in both groups. Group 1 showed threefold serum aldosterone, (P = 0·001) 20-fold ACTH (P = 0·003) and twofold cortisol (P = 0·001) increases intra-operatively, unlike group 2. Both groups had a twofold BNP increase in POD 1 that remained above normal on POD 7 only in group 1 (P = 0·02; P = 0·019 vs group 2). CONCLUSION: Alleviation of aldosterone release by epidural analgesia modulated the postoperative serum BNP pattern in patients with a low risk for cardiac diseases who underwent noncardiac surgery.

Serum Lactate As Reliable Biomarker of Acute Kidney Injury in Low-risk Cardiac Surgery Patients.

BACKGROUND: Cardiac surgery-associated acute kidney injury (CSA-AKI) frequently occurs in patients assessed as low-risk for developing CSA-AKI. Neutrophil Gelatinase-Associated Lipocalin (NGAL), Kidney Injury Molecule-1 (KIM-1) and lactate are promising biomarkers of CSA-AKI but have not yet been explored in low-risk patients. AIM: To evaluate urinary NGAL (uNGAL), KIM-1 and lactate as biomarkers of CSA-AKI in patients with low-risk for developing CSA-AKI. METHODS: This prospective, observational study included 100 adult elective cardiac surgery patients assessed as low-risk for developing CSA-AKI. UNGAL, KIM-1 and lactate were measured preoperatively, at the end of cardiopulmonary bypass (CPB) and 3, 12, 24 and 48 h later. RESULTS: Fifteen patients developed CSA-AKI. Patients with CSA-AKI had significantly higher lactate but similar uNGAL and KIM-1 levels compared to patients without CSA-AKI. Unlike uNGAL and KIM-1, postoperative lactate was good biomarker of CSA-AKI with the highest odds ratio (OR) 2.7 [1.4-4.9] 24 h after CPB. Peak lactate concentration ≥ 4 mmol/L carried dramatically higher risk for developing CSA-AKI (OR 6.3 [1.9-20.5]). CONCLUSIONS: Unlike uNGAL and KIM-1, postoperative lactate was significant independent predictor of CSA-AKI with the highest odds ratio 24 h after CPB.