Platelet Distribution Width Difference as Biomarker for Acute Kidney Injury in Cardiac Surgery: Study

AKI is a common and severe clinical condition that occurs after cardiac surgery with an increased risk of morbidity and mortality. It is caused due to multiple reasons and is more frequently seen in individuals with preexisting kidney disease. PDW is a marker for platelet activation and is a biomarker used for platelet size variability. Previous research shows that platelet distribution width (PDW) can potentially predict AKI due to its links with inflammatory and cardiovascular conditions. Cardiac surgery can influence PDW due to changes in hemodynamics, the onset of inflammation, and the need for blood transfusion. Elevated PDW has been linked to renal injury due to chronic kidney disease. As there is ambiguity on PDW’s role in predicting AKI after cardiac surgery, researchers conducted a study to investigate the potential role of PDW as a predictive marker for AKI in cardiac surgery patients.

A retrospective study was carried out by including adult cardiac surgery patients with preoperative renal dysfunction (eGFR between 15 and 60 ml/min/1.73m²). Necessary clinical data was collected from electronic medical records including cardiac function metrics, surgery details, and postoperative outcomes. The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines were used to assess the AKI and daily serum creatinine measurements were used to monitor postoperative renal function. PDW was measured preoperatively and immediately after postoperatively and the difference (dPDW) between the two was calculated. Multivariable logistic regression models assessed the association between dPDW and AKI, with adjustments for confounders. Subgroup analyses were also done to verify consistency across groups.

Findings:

• AKI occurred in 53.10% (513/966) of patients, and all the patients showed a significant increase in PDW (P < 0.001).
• After adjusting confounders, dPDW was identified as a significant risk factor for AKI.
• When compared to the patients in the lowest quartile, those in the highest dPDW quartile (Q4) had a 195% higher AKI risk.
• Trend analysis showed an increase in the risk of AKI with higher dPDW quartiles (P for trend < 0.001).
• Youden index showed that dRDW = 1.1 was identified as the optimal diagnostic cut-off value for AKI.
• Subgroup analyses and interaction tests showed a robust association between dPDW and AKI in all subgroups (P for interaction > 0.05).

Thus, the study concluded that PDW can be used as a potential biomarker for AKI risk in cardiac patients. Monitoring the difference in PDW helps in the early identification and timely management of individuals with an increased risk for AKI. Further research can be done to use this PDW measurement in clinical practice for timely intervention.

Further reading: Su, Y., Xu, X., Luo, Z. et al. Association between perioperative platelet distribution width changes and postoperative acute kidney injury in patients with renal insufficiency: a retrospective study. BMC Nephrol 25, 393 (2024). https://doi.org/10.1186/s12882-024-03802-9