CHICAGO – Lower extremity duplex scans should be performed prior to colorectal surgery, and anticoagulation should be tailored to the result, findings from a randomized clinical trial suggest.
The findings also raise questions about the fairness of financial penalties imposed by the Centers for Medicare & Medicaid Services for perioperative venous thromboembolism, Dr. Karen Zaghiyan of Cedars Sinai Medical Center, Los Angeles said at the annual meeting of the American Surgical Association.
In 376 consecutive adult patients undergoing laparoscopic or open major colorectal surgery who had no occult preoperative deep vein thrombosis (DVT) on lower extremity venous duplex scan and who were randomized to preoperative or postoperative chemical thromboprophylaxis (CTP) with 5,000 U of subcutaneous heparin, no differences were seen with respect to the primary outcome of venous thromboembolism within 48 hours of surgery, Dr. Zaghiyan said.
“There was no significant difference in our primary outcome – early postoperative VTE [venous thromboembolism] – in patients managed with postoperative or preoperative prophylaxis,” she said, noting that three patients in each group developed asymptomatic intraoperative DVT, and two additional patients in the postoperative treatment group developed asymptomatic DVT between postoperative day 0 and 2.
Two additional patients in the postoperative treatment group developed clinically significant DVT between postoperative day 2 and 30.
“Both patients had a complicated prolonged hospital course, and developed DVT while still hospitalized. This difference still did not reach statistical significance, and there were no post-discharge DVT or PEs [pulmonary embolisms] in the entire cohort,” she said.
Bleeding complications, including estimated blood loss and number receiving transfusion, were similar in the two groups, she said, noting that no patients developed heparin-induced thrombocytopenia, and that hospital stay, readmissions, and overall complications were similar between the two groups.
Study subjects had a mean age of 53 years, and 52% were women. The preoperative- and postoperative treatment groups were similar with respect to demographics and preoperative characteristics. They underwent lower extremity venous duplex just prior to surgery, immediately after surgery in the recovery room, on day 2 after surgery, and subsequently as clinically indicated.
Thromboprophylaxis in the preoperative treatment group was given in the “pre-op holding area” then 8 hours after surgery and every 8 hours thereafter until discharge. Thromboprophylaxis in the postoperative treatment group was given within 24 hours after surgery, and then every 8 hours until discharge.
Preoperative and postoperative CTP were equally safe and effective, and since occult preoperative DVT is twice as common as postoperative DVT, occurring in a surprising 4% of patients in this study, the findings support preoperative scans and anticoagulation based on the results – especially in older patients and those with comorbid disease, Dr. Zaghiyan said.
The findings could help improve patients care; although VTE prevention and chemical prophylaxis in colorectal surgery have been extensively studied, current guidelines are vague, with both the American College of Chest Physicians and the Surgical Care Improvement Project recommending that prophylaxis be initiated 24 hours prior to or after major colorectal surgery, she said.
The findings could also help avoid CMS penalties for postoperatively identified VTE,” she added.
Further, those penalties may not be supported by the clinical data; in this study, the majority of early postoperative DVTs were unpreventable, with no additional protection provided with preoperative prophylaxis, she explained.
“CMS should reevaluate the financial penalties, taking preventability into account,” she said.
Dr. Zaghiyan reported having no disclosures.
The complete manuscript of this presentation is anticipated to be published in the Annals of Surgery pending editorial review.