Correlation between preoperative anemia and lower extremity deep vein thrombosis in patients after elective lumbar fusion

Abstract

BACKGROUND: Lower extremity deep vein thrombosis is a catastrophic complication after lumbar spine fusion, and previous studies have shown that some patients, such as those with prosthetic arthroplasty and abdominal surgeries, suffer from a combination of preoperative anemia, which predisposes them to postoperative deep vein thrombosis of the lower extremities. However, whether preoperative anemia increases the risk of lower extremity deep vein thrombosis after lumbar spine fusion is unclear. OBJECTIVE: To investigate the correlation between preoperative anemia and deep vein thrombosis of the lower extremities in patients after lumbar fusion. METHODS: The clinical data of 1 178 patients who underwent lumbar spinal fusion treatment admitted to Third Affiliated Hospital of Anhui Medical University from January 2020 to December 2023 were retrospectively analyzed. According to whether or not the patients developed lower extremity deep vein thrombosis after the operation, the patients were divided into the deep vein thrombosis group (ultrasound report suggestive of lower extremity deep vein thrombosis) and the non-deep vein thrombosis group (ultrasound report suggestive of no lower extremity deep vein thrombosis). The incidence of anemia was compared between the two groups, and risk factors for lower extremity deep vein thrombosis in lumbar fusion patients were determined by univariate analysis and multivariate logistic regression analysis. RESULTS AND CONCLUSION: Among 1 178 patients, there were 43 cases (3.7%) in the deep vein thrombosis group and 1 135 cases (96.4%) in the non-deep vein thrombosis group. The incidence of preoperative anemia in the deep vein thrombosis group was 32.6%, significantly higher than that in the non-deep vein thrombosis group (10.9%, P < 0.05). Univariate analysis showed significant differences between the two groups in preoperative hemoglobin (P < 0.001), preoperative red blood cell count (P=0.028), D-dimer positivity (P=0.029), hypertension (P=0.019), number of fused segments (P=0.023), anemia (P < 0.001), and blood transfusion (P=0.006) (P < 0.05). Multivariate analysis showed that preoperative anemia (OR=4.221, 95%CI: 1.198-14.802, P=0.025) and D-dimer positivity (OR=2.023, 95%CI: 1.065-3.844, P=0.031) were risk factors for lower extremity deep vein thrombosis after lumbar fusion. These findings suggest that the incidence of preoperative anemia is relatively high in patients undergoing elective lumbar fusion, and preoperative anemia is an independent risk factor for deep vein thrombosis after lumbar fusion. It is recommended that preoperative anemia should be actively managed and corrected before elective lumbar fusion to reduce the risk of lower extremity deep vein thrombosis.

1. Introduction

Lumbar fusion is one of the common surgical procedures for adults with degenerative disc disease and lumbar spondylolisthesis causing chronic and debilitating symptoms [1-3]. Lower extremity deep vein thrombosis (DVT) is a common complication after elective orthopedic surgery and is an important factor leading to increased morbidity and mortality. According to studies by ZHAO et al. [4] and STROM et al. [5], the incidence of lower extremity DVT reaches 11.8% and 15.3%, respectively. Notably, DVT often lacks obvious symptoms, and routine lower extremity ultrasound screening has low sensitivity for asymptomatic DVT. In many cases, fatal pulmonary embolism is the first manifestation of lower extremity DVT. Therefore, identifying risk factors for DVT after lumbar fusion is particularly important.

For patients undergoing lumbar fusion, hemoglobin levels are often decreased due to advanced age, poor nutritional status, and unknown reasons. According to the National Health and Nutrition Examination Survey (NHANES), anemia is more common in the elderly than in younger individuals [6]. Studies have found considerable evidence of a significant association between preoperative anemia and surgical complications and mortality [7-10]. BARON et al. [11] studied 227,435 patients undergoing non-cardiac surgery and found that patients with preoperative hemoglobin below normal had higher in-hospital mortality than those with normal levels. Although preoperative anemia is not a direct causative factor for DVT, it significantly increases the risk of postoperative DVT through various indirect pathways, including tissue hypoxia/endothelial injury, hemodynamic changes, pro-inflammatory state, increased transfusion requirements, and limited mobility. Anemia often signals poor overall health and the presence of other potential prothrombotic factors [12-13]. However, in some domestic and international studies, it remains unclear whether preoperative anemia increases the incidence of lower extremity DVT after lumbar fusion.

Given this, the purposes of this study were: (1) to investigate the prevalence of preoperative anemia in patients undergoing lumbar fusion; (2) to investigate the incidence of lower extremity DVT; and (3) to determine whether preoperative anemia is a risk factor for lower extremity DVT after lumbar fusion.