Decrease in serum alkaline phosphatase and prognostic relevance in adult cardiopulmonary bypass.

Area of Science:

• Cardiology
• Biochemistry
• Surgical Critical Care

Background:

• Cardiopulmonary bypass (CPB) triggers inflammatory responses.
• CPB may lead to alkaline phosphatase (AP) depletion due to its role in dephosphorylating detrimental extracellular nucleotides.
• Low AP levels post-cardiac surgery in children are linked to increased support needs and organ dysfunction, but this is less understood in adults.

Purpose of the Study:

• To investigate the perioperative development of AP depletion in adults undergoing CPB.
• To determine the clinical relevance and predictive value of AP depletion for early postoperative outcomes in adults.

Main Methods:

• Retrospective analysis of 183 adult patients undergoing mitral valve surgery with CPB.
• Serum AP levels were measured preoperatively and on postoperative days 1-15.
• Correlation of AP drop with perioperative parameters and outcomes using receiver operating characteristic (ROC) analysis.

Main Results:

• A >50% reduction in baseline AP predicted in-hospital mortality (AUC 0.807), prolonged ICU stay (AUC 0.707), prolonged mechanical ventilation (AUC 0.712), and dialysis requirement (AUC 0.736).
• Patients with >50% AP reduction had significantly decreased survival.
• High perioperative AP loss was associated with longer CPB duration and increased need for extracorporeal membrane oxygenation.

Conclusions:

• Increased perioperative alkaline phosphatase loss is associated with adverse early outcomes in adults undergoing CPB.
• Prospective trials are warranted to assess the efficacy of perioperative AP supplementation.