Duration of Anesthesia, Vascular Surgical Trauma, and Venous Thromboembolism

Abstract

To the Editor: Jaffer et al,1Jaffer AK Barsoum WK Krebs V Hurbanek JG Morra N Brotman DJ Duration of anesthesia and venous thromboembolism after hip and knee arthroplasty.Mayo Clin Proc. 2005; 80: 732-738PubMed Google Scholar in the June 2005 issue of the Mayo Clinic Proceedings, reported a marked association between the duration of anesthesia and postoperative venous thrombo-embolism (VTE) in patients who underwent joint arthroplasty. The authors stated that during anesthesia, venous stasis occurs (venographically evidenced), probably resulting from both the supine position and the effects of anesthesia (increased venous capacitance). They concluded that longer duration of anesthesia may be an important risk factor for postoperative VTE. Although venous stasis is a very important pathogenic factor for the development of VTE, it is useful to remember that surgery of the knee joint (extremely close to the vein) has a risk of VTE similar to surgeries that usually induce greater tissue trauma (hip or abdominal surgery).2Anderson Jr, FA Spencer FA Risk factors for venous thromboembolism.Circulation. 2003; 107: I-9-I-16Google Scholar Furthermore, in patients recovering from hip replacement, 90% of proximal thrombi occur on the operated side,2Anderson Jr, FA Spencer FA Risk factors for venous thromboembolism.Circulation. 2003; 107: I-9-I-16Google Scholar suggesting a local venous problem. Time-consuming arthroplasty results usually from anatomical difficulties and/or from inexperience or inability of the surgeon, which may lead to greater local trauma. The pressure and traction exerted by bones or instruments over adjacent tissues are sometimes enormous, and the veins are extremely close to the hip and knee joints. Usually, the greater the difficulty, the greater the traction. Vascular endothelium, which has antithrombotic properties, is friable and is removed easily from vessels with simple cotton; vascular endothelium probably is removed when vessels are compressed as well. We suggest that the marked association between the duration of anesthesia and postoperative VTE may also result from local vascular or endothelial trauma caused by anatomical difficulties and/or by surgeon inexperience or inability. Duration of Anesthesia, Vascular Surgical Trauma, and Venous Thromboembolism: In ResponseMayo Clinic ProceedingsVol. 80Issue 9PreviewWe wholeheartedly agree with Dr Martins do Vale's comment that local trauma to the veins during knee and hip replacement is 1 plausible mechanism by which longer duration of orthopedic surgery predisposes patients to VTE. Indeed, in our original article, we stated that it was impossible to conclude that longer duration of anesthesia is a causal factor for VTE and that it may be just a marker for any number of complexities or complications that may occur in the operating room. Full-Text PDF