Natural History Of Below-knee Deep Vein Thrombosis In Neurosurgical Patients
Georgios Tzavellas, MD1, Nektarios Charisis, MD1, Pavlos Texakalidis, MD2, Spyridon Giannopoulos, Medical Student1, Doreen Elitharp, RN, NP-C1, Apostolos Tassiopoulos, MD1.
1Stony Brook University Hospital, Stony Brook, NY, USA, 2Department of Neurosurgery, Emory University, Atlanta, GA, USA.
Objective: Neurosurgical procedures are associated with an increased incidence of perioperative venous thromboembolic (VTE) events often involving only the below-knee deep venous system. Our aim was to study the natural history of the below-knee VTE events in these patients.
Methods: In our hospital every VTE event is recorded and analyzed by a dedicated VTE team. A retrospective single-center chart review, of all neurosurgical patients who developed a below-knee Deep Venous Thrombosis (DVT) between 2014 and 2018, was performed. The rate of proximal propagation and of documented Pulmonary Embolism (PE) was recorded. A variety of clinical factors were investigated to determine predictors of VTE propagation. Descriptive statistics, univariate and multivariate logistic regression analyses were performed.
Results: We identified 221 neurosurgical patients who developed below-knee DVT during the study period. The mean age was 68 years (range 26-98). Of the 221 patients, 122 had undergone brain intervention, 37 spinal surgery and 62 were operated for traumatic brain or spinal cord injury. Seventy-three percent (73%) of the patients had contraindication for pharmacological thromboprophylaxis. Following the initial DVT diagnosis, 21 patients (9.5%) were treated with therapeutic anticoagulation, 64 patients (29%) were started on chemical thromboprophylaxis and serial duplex scans and 136 patients (61.5%) underwent only serial surveillance duplex. The incidence of proximal propagation of DVT was 1.8% (N=4), while the incidence of PE was 9.5% (N=21). In all patients with DVT propagation and in 15 patients with subsequent PE the intramuscular veins (gastrocnemius/ soleal) were involved. Former smoking (OR=3.3, CI=1.11-9.76, p=0.031) and current smoking (OR=4.48, CI=1.08-18.44, p=0.038) were independent predictors of PE following DVT. Patients who received mechanical thromboprophylaxis as compared to no treatment following diagnosis of DVT, showed a reduction in the risk of PE in univariate (OR=0.27;CI=0.06-1.02, p=0.055) and multivariate (OR=0.27;CI=0.06-1.13, p=0.07) analysis respectively; however statistical significance was not reached.
Conclusions: The incidence of proximal DVT propagation and PE in neurosurgical patients who developed acute below-knee DVT in the postoperative period were 1.8% and 9.5% respectively and occurred only in patients with contraindication to thromboprophylaxis. Involvement of the intramuscular veins (gastrocnemius/ soleal) and smoking history increased the risk of PE. Most PEs were small, however the high incidence may suggest a need for selective IVC filter placement in patients with below-knee DVT that involves the intramuscular veins.
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