Venous thromboembolism (VTE) is a severe and possibly fatal complication of a surgical procedure. VTE can complicate the more than 300 million worldwide annually performed surgeries. They say pharmacological prophylaxis decreases the risk of a VTE event but can increase the risk of bleeding. When using a prophylactic dose of low-molecular-weight heparin (LMWH), the risk of bleeding is minimally increased if the surgical technique is well performed, I think.
In the present day, pharmacological prophylaxis (e.g., 40 mg Enoxaparin id) for 28 days following gastrointestinal cancer surgery is recommended based on worldwide literature. Unfortunately, VTE prophylaxis is not consistent among surgeons and among hospitals, because some doctors keep resisting using correct VTE prophylaxis. Why is that true? Some doctors say that it is a pharmaceutical company’s fabricated idea, while others are simply not updated. In fact, starting time and duration of prophylaxis are still crucial questions. As Caprini said, many surgeons start prophylaxis only after surgery because they say, “bleeding is a surgeon’s problem while thrombosis is a God’s problem”. They are thinking of lawsuits, of course. Additionally, some studies showed a reduction in VTE events if prophylaxis was initiated before surgery, yet not statistically significant. A Cochrane review concluded that extended prophylaxis has better results for VTE reduction than in-hospital-only prophylaxis for abdominal and pelvic surgeries. However, they did not separate cancer surgeries from benign surgeries. Does a patient submitted to laparoscopic repair of an abdominal wall hernia need extended prophylaxis? Early ambulation is also prophylaxis. Does an ambulatory surgery patient need prophylaxis other than early ambulation? If yes, that patient is probably unfit for ambulatory surgery.
A recent meta-analysis published in BJS by Tino Singh et al gives us accurate data about the timing of symptomatic VTE after surgery. These data are very important as they can change the mind of some surgeons and can influence guideline makers. To decide for how long a VTE prophylaxis should be administered, we must know when the postoperative VTE events occur. This group of doctors from Finland, Canada, the UK, and the Netherlands, reviewed 22 prospective studies that included patients from the year 2000 or later. They included 1864875 patients who underwent a surgical procedure (general surgery, urological, gynecological, orthopedic, thoracic, plastic, breast, transplant). All studies reported the timing of at least 20 symptomatic postoperative VTE events (PE or DVT). A drawback is that malignant disease is mixed with benign disease, making it impossible to take conclusions about in which procedures/diseases the events occurred. Although, 8 out of 22 studies included only malignant patients. Additionally, comorbidities were not considered nor were the patients’ mobility status.
The primary outcome was the occurrence of VTE events within the first 28 days (four weeks) after surgery. A total of 24927 VTE events were reported. Patients with a malignant disease were 85%. In 20 studies VTE was confirmed with imaging findings. Pharmacological prophylaxis and mechanical prophylaxis were estimated (0 to 27 days and 0 to 9 days, respectively). Because of the high risk of bias in 21 studies, the quality of the evidence was considered moderate. The results were consistent in all studies.
The majority of the postoperative VTE events occurred during the first week (47.1%). A total of 26.9% of events occurred during the second week, 15.8% during the third week, and 10.1 % during the fourth postoperative week. This means that 77.7% of postoperative VTE events occurred during the first two weeks. According to the authors these data “represent more accurate and up-to-date estimates of the timing of VTE within the first 28 days after surgery”. Although almost half of the VTE events occur during the first postoperative week, a substantial number of events occur during the third and fourth weeks. In that setting, it may prove the “importance of extended prophylaxis, especially in patients with a high risk of VTE”. As 85% of patients included in this meta-analysis were cancer patients, these data may eventually support the 28 days of postoperative pharmacological prophylaxis recommendation following cancer surgery (e.g., colorectal). However, in the study, the authors do not present data on the type of cancer and the proportion of VTE events per cancer type. Additionally, the proportion of VTE events in benign diseases is not given. All those data would be interesting to analyze.
Do you enjoy adrenal surgery?
Must have this new book!
Costa Almeida CE, editor. Posterior Retroperitoneoscopic Adrenalectomy.Indications, Technical Steps and Outcomes. Switzerland: Springer; 2023.
In sum, 77,7% of VTE events occur during the first two weeks after surgery, a substantial number of events occur in the third and fourth weeks, and extended prophylaxis is important in high-risk patients. However, the question of when to start prophylaxis is still lacking a correct answer. In my opinion, it should be initiated before surgery since the surgical procedure is an important risk factor for thrombus formation.
Link to article:
Dr. Carlos Eduardo Costa Almeida
General Surgeon
Comentários