Sepsis is the leading course of morbidity and mortality in critically ill patients. This study aimed to evaluate the predictive value of the platelet aggregation for mortality in patients with sepsis. In addition, the relationship between impaired mitochondria and the platelet aggregation was explored.

This was a prospective, observational cohort study. The platelet aggregation rate in response to adenosine diphosphate (ADP) was assessed. The primary outcome was 28-day mortality. Platelet mitochondrial parameters, including adenosine triphosphate(ATP), mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) opening, were measured. Platelet mitochondrial ultrastructure was observed using transmission electron microscopy.

86 patients with 65 survivors and 21 non-survivors were enrolled. Platelets of non-survivors with sepsis were hyporesponsive to ADP, in terms of maximal aggregation rate (P < 0.001). Receiver operating characteristic curves analysis demonstrated that the AUC estimated 28-day mortality for platelet aggregation rate was 0.814. At the optimal cut-off value of 35.8% for platelet aggregation rate, the sensitivity was 86.2% and the specificity was 66.7%. Kaplan-Meier analysis showed that a platelet aggregation rate of less than 35.8% was associated closely with poor survival. After adjusting for lactate by Cox regression analysis, platelet aggregation rate was identified as an independent predictor for the probability of 28-day mortality. Compared with survivors, non-survivors showed a significant reduction in platelet ATP and MMP-index (both P < 0.001), and a remarkable increase in mPTP opening (P < 0.001). ATP and MMP-index were positively correlated with platelet aggregation rate (R square=0.75, R square=0.44, respectively).

Platelet aggregation rate could be an early predictive biomarker for mortality in sepsis. Impaired platelet mitochondrial activity affects platelet aggregation and correlates with the severity of sepsis.