“Among patients undergoing vascular surgery, thromboprophylaxis with anticoagulants showed a trend towards reduced incidence of VTE [venous thromboembolism] when compared to placebo,” Tarek Haykal (Duke University Medical Center, Durham, USA) and colleagues write in the Journal of Vascular Surgery: Venous and Lymphatic Disorders, reporting the main conclusion of a meta-analysis and systematic review of randomised controlled trials (RCTs). However, the authors note that this finding lacked statistical significance and state that there is a need for larger randomised prospective trials in the future.
VTE is a well-known complication associated with surgical procedures and Haykal et al relay that the implementation of thromboprophylaxis in this population has become a “vital aspect of perioperative care to decrease VTE-associated morbidity and mortality risk”. However, they add, data assessing the role of thromboprophylaxis for patients undergoing vascular surgery are lacking.
The objective of the present study was to assess the role of thromboprophylaxis by low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) in vascular surgery. Haykal and colleagues detail that they searched MEDLINE, Embase and the Cochrane Collaboration Central Register of Controlled Trials from inception until December 2020, for RCTs assessing the role of thromboprophylaxis in vascular surgery.
A total of eight RCTs met the inclusion criteria, including 3,130 patients, the authors communicate in their paper. The mean age of the patients was 55.35 years and 45% were female.
Haykal et al report that, compared to placebo, anticoagulant use was associated with a reduction of deep venous thrombosis (DVT; relative risk [RR], 0.34; 95% confidence interval [CI], 0.11–1.05; p=0.06; I2=68%), and pulmonary embolism (PE; RR, 0.17; 95% CI, 0.02–1.22; p=0.08; I2=41%), but this trend did not reach statistical significance.
There was no difference for bleeding outcomes between anticoagulants and placebo (RR, 0.9; 95% CI, 0.05–15.01; p=0.94; I2=76%), the researchers continue. Furthermore, they reveal that there was no significant difference in outcomes when LMWH was compared directly to UFH.
Haykal and colleagues conclude that, for patients undergoing vascular surgery, evidence from the studies included in this meta-analysis and systematic review suggest that thromboprophylaxis with anticoagulants (LMWH or UFH) is “likely effective” at preventing VTE when compared with placebo. However, this finding lacked statistical significance, “primarily due to underpowered studies and a lack of robust data to better prove the thromboprophylaxis benefit with anticoagulants in this patient population,” they write.
They stress that, in future, there is a need for larger randomised prospective trials that are “better designed and powered to detect any benefit”.