Resident Physician University of Colorado Aurora, Colorado, United States
Background: Cardiac surgery reduces long-term morbidity and mortality but is associated with a 1 in 50 chance of death within 30 days. Standard post-operative management is effective for most patients, but a minority experience complications leading to death. Early prediction of who is at an increased risk of death would allow time for intervention and a greater chance for survival. The most common cause of death after cardiac surgery is heart failure leading to tissue malperfusion and organ injury. The majority of platelets are consumed after cardiac surgery and must be replaced by new platelet production, which requires sufficient blood flow provided by the cardiac output. Therefore, we hypothesized that failure of platelet count recovery after cardiac surgery would be an early diagnostic indicator of increased risk of death.
Aims: Aim 1: Compare platelet count recovery after cardiac surgery between survivors and non-survivors. Aim 2: Determine the optimal platelet count and time for distinguishing between survivors and non-survivors.
Methods: The study was approved by the Colorado Multiple Institution Review Board. We performed a retrospective study of 2,306 patients undergoing cardiac surgery at the University of Colorado Hospital. We collected patient data from 2011 to 2022 from the electronic health record. We compared platelet count recovery in the first 7 days between survivors and non-survivors over time. We used JMP16 software to calculate Youden’s J statistic and determine the optimal cutoff point over the first 7 post-operative days.
Results: Survivors had a significantly higher platelet count on post-operative day 4 through 7 compared to non-survivors (Figure 1). A platelet count less than 112x10^9/L on day 4 discriminated between survivors and non-survivors (Table 1).
Conclusion(s): Platelet count recovery after cardiac surgery may be a pragmatic diagnostic tool for identifying patients at an increased risk of death and allow for therapeutic intervention.
