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

Abstract

IntroductionLimited 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.MethodsSub-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.ResultsMean 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).ConclusionsAlkaline 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.

Preoperative Serum Alkaline Phosphatase and Clinical Outcome of Off-Pump Coronary Artery Bypass Surgery

“…13-15 A recent study reported that low ALP following cardiothoracic surgery in infants is independently associated with increased vasoactive/inotropic requirements, intubation time, and length of hospital stay. 16 Thus, vascular effects of ALP on clinical outcome may be offset by its protective effects in the attenuation of inflammatory reactions following OPCAB. 14 Using the Park et al data, 12 we evaluated the potential association between revascularization technique (OPCAB vs. PCI) and adverse outcome according to ALP level.…”

“…13- 15 In a previous study, low postoperative ALP level was associated with worse clinical outcome in infants undergoing cardiothoracic surgery. 16 Therefore, the relationship between ALP and adverse outcome in CABG patients may differ from that in PCI patients. If so, then ALP level could be used to determine the appropriate revascularization technique.…”

Alkaline Phosphatase as a Treatment of Sepsis-Associated Acute Kidney Injury

“…Indeed, BiAP infusion into sepsis patients with AKI showed that several well established serum markers of systemic inflammatory activity, such as C-reactive protein, interleukin-6, and LPS-binding protein, responded within several hours after treatment and their decrease remained more pronounced compared with the placebo group during the following days (Pickkers et al, 2012). In addition, a reduction in AP levels after cardiac surgery was recently demonstrated to be associated with increased procalcitonin levels and more pronounced hemodynamic instability (Davidson et al, 2012).…”

Bone matrix vesicle-bound alkaline phosphatase for the assessment of peripheral blood admixture to human bone marrow aspirates

“…However, since lower total ALP levels have been measured in patients after cardiac surgery, it is important to sample blood prior to sternotomy [37]. Furthermore, we used BM and PB serum instead of EDTA or heparin plasma during the ALP experiments, since EDTA inhibits ALP activity [18] and heparin causes ruptures in the agarose gel.…”