P53: Postoperative Leukocytosis Trends in Ventricular Assist Device Implantation and Coronary Artery Bypass Graft Surgery

Abstract

Background and Objective: Leukocytosis is a marker of inflammation due to infectious or non-infectious etiologies and is seen after coronary artery bypass graft surgery (CABG) and left ventricular assist device (LVAD) placement. Differentiating reactive postoperative leukocytosis from post-operative infection can drive antimicrobial stewardship initiatives. In this study, we aimed to describe the expected temporal trend of white blood cell (WBC) counts after LVAD placement compared to CABG. Methods and Analysis: We conducted a retrospective chart review of adult patients who underwent durable LVAD implantation or on-pump CABG between 2017-2019 at a single university-affiliated tertiary care hospital in Washington, DC. We excluded patients who were undergoing LVAD exchange, percutaneous VAD placement, had kidney failure requiring renal replacement therapy or transplant, had thromboembolism <14 days before the procedure, clinical or microbiological evidence of systemic infection <7 days before the procedure, were on steroids ≥5 mg prednisone daily, had a history of hematologic malignancy or acquired immunodeficiency syndrome. We compared the WBC count trend postoperatively after LVAD placement vs. CABG until day 24 or discharge, whichever was earlier. Secondary outcomes included comparing number of patients with bacteremia or clinical evidence of infection requiring antimicrobial therapy among the two groups. Results: We reviewed the charts of 116 LVAD patients and 134 CABG patients with median age 61 years [Interquartile Range (IQR) 53.0, 67.0] and BMI 28.4 kg/m2 [IQR 25.5, 32.8]. In the LVAD group, there was a peak in median WBC count to 14.2 (x103/ μL) [IQR 11.3, 17.6] on Day 2 post-operatively and another peak on Day 10 post-operatively to 14.1 [IQR 10.6, 18.4]. In the CABG group, median WBC peak was observed at Day 2 post-operatively at 11.8 [9.1, 14.2] (Fig. 1). There were 10 (8.6%) LVAD patients with clinical or microbiological evidence of infection compared to 2 (1.5%) CABG patients (p = 0.01). After excluding patients with infections there was no change observed in the trend of the postoperative WBC counts. Conclusion: Post-operative leukocytosis is common in cardiopulmonary bypass and peak WBC are higher in LVAD patients than CABG patients. WBC counts peak in LVAD patients at day 2 and 10 postoperatively. This expected peak should be taken into consideration while evaluating patients for infections and antimicrobial therapy.