Alkaline phosphatase activity after cardiothoracic surgery in infants and correlation with post-operative support and inflammation: a prospective cohort study

• Published in: Critical care (London, England) Vol. 16; no. 4; p. R160
• Main Authors: Davidson, Jesse, Tong, Suhong, Hauck, Amanda, Lawson, D Scott, Jaggers, James, Kaufman, Jon, da Cruz, Eduardo
• Format: Journal Article
• Language: English
• Published: London BioMed Central 20.08.2012; BioMed Central Ltd
• Subjects: Alkaline phosphatase; Alkaline Phosphatase - blood; Analysis; Biomarkers - blood; C-reactive protein; C-Reactive Protein - metabolism; Calcitonin - blood; Calcitonin Gene-Related Peptide; Cardiac Surgical Procedures - adverse effects; Cardiotonic Agents - therapeutic use; Coronary artery bypass; Critical Care Medicine; Emergency Medicine; Female; Heart; Humans; Infant; Infant, Newborn; Infants; Inflammation; Inflammation - enzymology; Inflammation - etiology; Intensive; Intubation, Intratracheal; Length of Stay; Male; Medicine; Medicine & Public Health; Patient outcomes; Phosphatases; Postoperative Care; Prospective Studies; Protein Precursors - blood; Surgery; Thoracic Surgical Procedures - adverse effects; Moderate Inverse Correlation; Total Alkaline Phosphatase Activity; Alkaline Phosphatase Activity; Procalcitonin; Cardiac Intensive Care Unit
• ISSN: 1364-8535; 1466-609X; 1364-8535; 1466-609X
• DOI: 10.1186/cc11483

Introduction Limited evidence suggests that serum alkaline phosphatase activity may decrease after cardiac surgery in adults and children. The importance of this finding is not known. Recent studies, however, have identified a potential role for alkaline phosphatase as modulator of inflammation in multiple settings, including during adult cardiopulmonary bypass. We sought to describe the change in alkaline phosphatase activity after cardiothoracic surgery in infants and to assess for a correlation with intensity and duration of post-operative support, markers of inflammation, and short-term clinical outcomes. Methods Sub-analysis of a prospective observational study on the kinetics of procalcitonin in 70 infants (≤90 days old) undergoing cardiothoracic surgery. Subjects were grouped based on the use of cardiopulmonary bypass and delayed sternal closure. Alkaline phosphatase, procalcitonin, and C-reactive protein (CRP) levels were obtained pre-operation and on post-operative day 1. Mean change in alkaline phosphatase activity was determined in each surgical group. Generalized linear modeling and logistic regression were employed to assess for associations between post-operative alkaline phosphatase activity and post-operative support, inflammation, and short term outcomes. Primary endpoints were vasoactive-inotropic score at 24 hours and length of intubation. Secondary endpoints included procalcitonin/CRP levels on post-operative day 1, length of hospital stay, and cardiac arrest or death. Results Mean decrease in alkaline phosphatase was 30 U/L (p = 0.01) in the non-bypass group, 114 U/L (p<0.0001) in the bypass group, and 94 U/L (p<0.0001) in the delayed sternal closure group. On multivariate analysis, each 10 U/L decrease in alkaline phosphatase activity on post-operative day 1 was independently associated with an increase in vasoactive-inotropic score by 0.7 (p<0.0001), intubation time by 6% (p<0.05), hospital stay by 5% (p<0.05), and procalcitonin by 14% (P<0.01), with a trend towards increased odds of cardiac arrest or death (OR 1.3; p = 0.06). Post-operative alkaline phosphatase activity was not associated with CRP (p = 0.7). Conclusions Alkaline phosphatase activity decreases after cardiothoracic surgery in infants. Low post-operative alkaline phosphatase activity is independently associated with increased procalcitonin, increased vasoactive/inotropic support, prolonged intubation time, and prolonged hospital stay. Alkaline phosphatase may serve as a biomarker and potential modulator of post-operative support and inflammation following cardiothoracic surgery in infants.