Thrombocytopenia After Cardiopulmonary Bypass is Associated with Increased Morbidity and Mortality
Background
Thrombocytopenia is a risk factor for morbidity and mortality in critically ill patients, and is common following cardiopulmonary bypass (CPB). In this study, we evaluate whether thrombocytopenia following CPB is an independent risk factor for post-operative morbidity and mortality.
Methods
We retrospectively evaluated 1,364 patients requiring CPB at University of Colorado Hospital between January 2011 and May 2016. Platelet nadir, absolute change in platelets, and percent change in platelets were modeled as continuous variables. Patients with post-operative thrombocytopenia (defined a nadir <75×103/μL within 72 hours) were also compared to patients without thrombocytopenia in a propensity-matched model. The primary outcome was in-hospital mortality, and secondary outcomes included post-operative infection, post-operative acute kidney injury (AKI), post-operative stroke, and prolonged intensive care unit (ICU) and hospital lengths of stay (LOS).
Results
Post-operative thrombocytopenia occurred in 356 (26.0%) patients. In multivariable analysis platelet nadir was significantly inversely associated with mortality [0.955 (0.934-0.975), p<0.001], post-operative infection [0.992 (0.986-0.999), p=0.03], AKI (all stage) [0.993 (0.988-0.998), p = 0.01], AKI (stage 3) [0.966 (0.951-0.982), p <0.001], post-operative stroke [0.974 (0.956-0.992), p=0.006] prolonged ICU stay [.0986 (0.981-0.991), p<0.001], and hospital LOS [0.998 (0.997-0.999), p=0.001]. Percent change in platelets from baseline was also significantly associated with all primary and secondary outcomes.
Conclusions
Post-operative thrombocytopenia is independently associated with post-operative mortality, AKI, infection, stroke, and prolonged ICU and hospital LOS. Serial platelet monitoring may help identify patients at higher risk of post-operative complications. Further studies investigating strategies to reduce post-operative thrombocytopenia, including reducing CPB time, are needed.
