PracticeUpdate: Conference Series - EHA 2018

Low-Dose Heparin May Be Warranted in Patients Undergoing Lower Limb Surgical Revascularization Prudent to start thromboprophylaxis 3.5–4 days after surgery

The 2012 American College of Chest Physicians (ACCP) guidelines for the prevention of venous thromboembolism in non-orthopedic surgical patients recommend the use of pneumatic compression devices (PCDs), but pharmacological thromboprophylaxis with low-dose heparin may be warranted in patients undergoing lower limb surgical revascularization. T he research team, led by Anmol Baranwal, MD, with the MacNeal Hospital in Berwyn, Illinois, concluded that because bleeding is a potential

of detection was more than a week after surgery,” he added, noting that the authors’ recommenda- tion for delaying chemoprophylaxis for 3–4 days is contradicted by findings from the Michigan Surgical Quality Collaboration. That study, published in the Journal of Vascular Surgery earlier this year, found that approximately 75% of patients received phar- macological chemo prophylaxis after major vascular surgery. In these patients undergoing lower extremity bypass, the incidence of DVT was only 1.1%. “They examined the timing of initiation of chemoprophylaxis post-operatively and found that it was most effec- tive if initiated within 24 hours post-op, the so-called 'early group', rather than at a later time point, and that early chemoprophylaxis was not associated with an increase in the risk of hemorrhagic side effects,” Dr. Eidt said. Javier Vasquez, MD, with Texas Vascular Associates and Medical Director of Surgical Services with the Baylor Scott & White Heart and Vascular Hospital, noted that the average time to identification of DVT noted in the study, 7.6 days, raised questions about the role ambulation and the calf pump effect would have had on the results. He cited a recent large multicenter retrospective review in the United States that found only 30% of hospitalized vascular patients received adequate DVT prophylaxis. “This was certainly surprising considering the recent pres- sure on hospital systems in the US to adhere to this certain ‘core measure.’ [It] certainly points to a need for improvement.” Several obstacles are present in post-operative vascular patients that are unique to this specialty, said Dr. Vasquez. These include the prevalence

complication in patients undergoing lower limb sur- gical revascularization, who are not good candidates for PCDs, it might be prudent to start thromboprophy- laxis 3.5–4 days after the surgery. Charts for 359 patients who had a lower limb surgical revascularization were evaluated for postoperative deep vein thrombosis (DVT) or consequential pulmo- nary embolism (PE). Overall, 5 patients (1.4%) were recognized to have a new DVT/PE within 3 months of the surgery. Patients had a newDVT/PE on average at 7.6 days after surgery. “It has generally been thought by vascular surgeons that the risk of post-operative DVT following lower extremity bypass surgery is relatively low in com- parison to other types of surgery. The basis for this belief is the fact that systemic intravenous heparin is administered during the operation when patients are thought to be at highest risk for venous stasis,” John F. Eidt, MD, vice chair of vascular surgery with the Baylor Scott & White Heart and Vascular Hospital in Dallas, told Elsevier’s PracticeUpdate . With respect to the present study, Dr. Eidt noted that there did not appear to be a standardized imag- ing protocol to detect subclinical DVT. “Thus, only patients with clinical indications for testing would have been evaluated. This would suggest that some cases of asymptomatic DVT would go undetected due to the retrospective nature of this study.” “The absence of a routine screening protocol might also explain the fact that the average time

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PRACTICEUPDATE CONFERENCE SERIES • EHA 2018