Normal preoperative white blood cell count is predictive of outcomes for endovascular procedures

Abstract

An abnormally elevated preoperative white blood cell count (WBC) has been associated with postoperative morbidity and mortality. However, it is unknown if a normal WBC is predictive of postoperative outcomes following vascular interventions. Thus, the objective of this study is to determine if a WBC within the normal range is predictive of outcomes following vascular interventions. The medical records of patients undergoing endovascular and open repair of carotid stenosis, aortic aneurysm, and peripheral arterial disease from 1999 to 2009 were retrospectively reviewed. Major adverse events (MAE) were defined as death, stroke, and myocardial infarction. Of 1773 cases with normal preoperative WBC (3.5-10.5 K/μL), there were 804 [45.3%] endovascular and 969 [54.7%] open vascular surgeries. Patients with complications (55) or MAE (19) after endovascular intervention had higher preoperative WBC compared with patients without complications (WBC 7.7 ± 1.47 vs 7.1 ± 1.57, respectively, P = .002) or MAE (WBC 8.3 ± 1.26 vs 7.1 ± 0.06, respectively, P = .001). No difference was observed for patients who received open surgery. Patients undergoing endovascular intervention were 2.3, 4.8, and 22 times more likely to experience complications (P = .004), MAE (P = .003), or death (P = .036) when WBC exceeded 7.5 K/μL. Multivariate analysis showed that preoperative normal WBC was an independent predictor of complications, MAE, and death in patients after endovascular procedures but only for death in patients after open vascular procedures. This study demonstrates a strong linear correlation between an increasing preoperative WBC within the normal range and an increased risk for postoperative complications and death following endovascular interventions. The study also found a significant curvilinear U-shaped relation between a normal preoperative WBC and death in the open surgical cohort, with patients in the very low and very high normal WBC range at an increased risk of death.