Perioperative thromboprophylaxis is highly variable in general surgery: results from a multicentre survey

Optimal Timing of Perioperative Chemical Thromboprophylaxis in Elective Major Abdominal Surgery: A Systematic Review and Meta-analysis

OBJECTIVE

To investigate the effect of the timing of chemoprophylaxis on venous thromboembolisms (VTEs) and bleeding rates in patients undergoing major abdominal surgery.

BACKGROUND

Postoperative bleeding and VTE incur significant morbidity, mortality, and health care costs. Chemoprophylaxis is used routinely to prevent VTEs but increases bleeding risk. The perioperative timing of chemoprophylaxis initiation may influence both VTE and bleeding risks. The optimal window for commencing chemoprophylaxis in the perioperative period is unclear.

METHODS

MEDLINE, EMBASE, Cochrane Library, and Web of Science databases were searched using PRISMA guidelines. Randomized trials and cohort studies published between January 1, 2000 to May 10, 2022, which reported on chemoprophylaxis timing as well as the incidence of VTE and bleeding after elective abdominal surgery were meta-analyzed.

RESULTS

From 6175 studies, 14 (24,922 patients) were meta-analyzed. Bariatric (4 studies), antireflux (1 study), hepato-pancreatic-biliary (5 studies), colorectal (1 study), ventral hernia (1 study), and major intra-abdominal surgeries (2 studies) were included. Chemoprophylaxis was initiated before skin closure in 10,403 patients, and postoperatively in 14,519 patients. Both symptomatic [risk ratios (RR), 0.81; 95% CI, 0.45-1.43; P =0.460] and overall (RR, 0.74; 95% CI, 0.45-1.24; P =0.250) VTE rates were comparable between study groups. Compared with postoperative chemoprophylaxis, early usage increased the risk of all bleeding (RR, 1.56; 95% CI, 1.13-2.15; P =0.007), major bleeding (RR, 1.63; 95% CI, 1.16-2.28; P =0.005), blood transfusion (RR, 1.48; 95% CI, 1.24-1.76; P <0.001), and reintervention (RR, 1.94; 95% CI, 1.19-3.18; P =0.008).

CONCLUSIONS

Our findings advocate for initiating chemoprophylaxis postoperatively in elective abdominal surgery to minimize bleeding risk without compromising VTE protection.

Postoperative Timing of Chemoprophylaxis and Its Impact on Thromboembolism and Bleeding Following Major Abdominal Surgery: A Multicenter Cohort Study

BACKGROUND

Major abdominal surgery is associated with bleeding and venous thromboembolism (VTE) risks. Chemoprophylaxis prevents VTE but increases bleeding risk. When compared with pre- and intra-operative chemoprophylaxis, recent evidence suggests that starting chemoprophylaxis postoperatively lowers the risk of bleeding without compromising VTE protection. This study investigates whether an optimal window exists in the postoperative period for initiating chemoprophylaxis in patients undergoing major abdominal surgery.

METHODS

Analysis of pooled data from four multicenter PROTECTinG studies, which investigated the timing of perioperative chemoprophylaxis on bleeding and VTE outcomes following major abdominal surgery. Patients that commenced chemoprophylaxis postoperatively were separated into quartiles based on timing of administration within the first 24 h post-surgery.

RESULTS

Overall, 4729 (Abdominal visceral resection N = 668, cholecystectomies N = 573, major ventral hernia repair N = 1701, antireflux surgery N = 1787) consecutive patients had chemoprophylaxis commenced within 24 h following elective surgery. Baseline characteristics were comparable between quartiles. Across quartiles and within each procedural type, the timing of starting chemoprophylaxis was not associated with bleeding (2.6, 1.7, 2.7 and 3.2%, p = 0.130) or clinical VTE (0.8, 0.2, 0.8 and 0.5%, p = 0.131), and did not predict their occurrences on multivariate analysis.

CONCLUSION

Chemoprophylaxis can be safely started at any time within 24 h post-skin closure in major abdominal surgery, without affecting bleeding or VTE risks. This finding encourages the standardization of chemoprophylaxis timing in the postoperative period to pre-defined times during the day to improve workflow efficiency and chemoprophylaxis compliance.

Optimal Timing of Perioperative Chemoprophylaxis in Patients With High Thromboembolic Risk Undergoing Major Abdominal Surgery: A Multicenter Cohort Study

OBJECTIVE

To determine whether early (before skin closure) versus postoperative chemoprophylaxis affects the incidence of venous thromboembolism (VTE) and bleeding following major abdominal surgery, in a high thromboembolic risk population.

BACKGROUND

Major abdominal surgery incurs both VTE and bleeding risks. Patients with high preoperative VTE risk derive the most benefit from chemoprophylaxis, but carry an increased risk of bleeding. The optimal window for chemoprophylaxis in the perioperative period, whereby both VTE and bleeding risks are minimized, is unknown.

METHODS

Analysis of pooled data from 5 multicenter studies including only high thromboembolic risk (Caprini score >4) patients. Clinical VTE was defined as radiographically proven symptomatic disease <30 days postsurgery. Major bleeding was defined as the need for blood transfusion, reintervention, or >20 g/L fall in hemoglobin.

RESULTS

From 5501 cases, chemoprophylaxis was initiated early in 1752 (31.8%) patients and postoperatively in 3749 (68.2%) patients. Baseline characteristics were similar between study groups. The incidence of clinical VTE was not associated with chemoprophylaxis timing [early 0.7% vs. postop 0.7%, odds ratio (OR): 1.11, 95% confidence interval (CI): 0.60-2.15, P =0.730]. Contrastingly, compared with postoperative chemoprophylaxis, early usage increased the risk of all bleeding (5.1% vs. 2.6%, OR: 2.04, 95% CI: 1.52-2.73, P <0.001) major bleeding (3.6% vs. 1.8%, OR: 1.99, 95% CI: 1.40-2.81, P <0.001), and reintervention (2.0% vs. 1.0%, OR: 2.10, 95% CI: 1.32-3.35, P =0.003). Early chemoprophylaxis independently predicted postoperative bleeding (OR: 1.71, 95% CI: 1.25-2.34, P <0.001), but not VTE.

CONCLUSIONS

In high VTE risk patients undergoing major abdominal surgery, chemoprophylaxis commenced postoperatively reduces bleeding risk without affecting clinical VTE risk.

Electronic Health Record Risk-Stratification Tool Reduces Venous Thromboembolism Events in Surgical Patients

Background

Venous thromboembolism is a preventable cause of morbidity and mortality after surgery. To ensure that patients receive appropriate venous thromboembolism chemoprophylaxis, a nonmandatory risk-stratification tool based on patient clinical condition was implemented through the electronic health record to stratify patient risk and recommend chemoprophylaxis. We hypothesized that implementing this tool would reduce postoperative venous thromboembolism events in general surgery as well as across all surgical services.

Methods

All adult patients undergoing inpatient surgical operations (January 2012–December 2019) at a single quaternary care center and Level 1 trauma center were abstracted from institutional electronic health record database and stratified into patients admitted before and after venous thromboembolism risk-stratification tool implementation. Bivariable analyses compared venous thromboembolism chemoprophylaxis prescription and venous thromboembolism events with implementation and screening among all surgical patients as well as in general surgery patient subset.

Results

A total of 64,377 adults underwent operations: 27,819 preimplementation and 36,558 postimplementation. A significant reduction in venous thromboembolism events occurred from pre- to post-tool implementation for all cases (0.77% vs 0.47%, P < .001). General surgery patients (n = 15,723) had a significant increase in chemoprophylaxis prescription (81.9% vs 86.0%, P < .001) and a significant reduction in venous thromboembolism events (1.41% vs 0.59%, P < .001). After tool implementation, use of extended postdischarge chemoprophylaxis was greater among general surgery patient subset than the entire patient cohort (46.7% vs 29.6%, P < .001).

Conclusion

The integration of a nonmandatory electronic health record risk-stratification tool was associated with a significant reduction in venous thromboembolism events. Extended chemoprophylaxis was prescribed in nearly half of general surgery patients at very high risk for postdischarge events.

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Implementing an electronic VTE risk-stratification tool reduced surgical VTE events.

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Even as a nonmandatory tool, risk stratification led to overall fewer VTE events.

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Postoperative VTE events were reduced by 39% after the tool was integrated in EHR.

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With the tool, general surgery had 58% less VTE events and improved prophylaxis use.

Early Versus Postoperative Chemical Thromboprophylaxis Is Associated with Increased Bleeding Risk Following Abdominal Visceral Resections: a Multicenter Cohort Study

BACKGROUND

Abdominal visceral resections incur relatively higher rates of postoperative bleeding and venous thromboembolism (VTE). While guidelines recommend the use of perioperative chemical thromboprophylaxis, the most appropriate time for its initiation is unknown. Here, we investigated whether early (before skin closure) versus postoperative commencement of chemoprophylaxis affected VTE and bleeding rates following abdominal visceral resection.

METHODS

Retrospective review of all elective abdominal visceral resections undertaken between January 1, 2018, and June 30, 2019, across four tertiary-referral hospitals. Major bleeding was defined as the need for blood transfusion, reintervention, or > 20 g/L fall in hemoglobin from baseline. Clinical VTE was defined as imaging-proven symptomatic disease < 30 days post-surgery.

RESULTS

A total of 945 cases were analyzed. Chemoprophylaxis was given early in 265 (28.0%) patients and postoperatively in 680 (72.0%) patients. Mean chemoprophylaxis exposure doses were similar between the two groups. Clinical VTE developed in 14 (1.5%) patients and was unrelated to chemoprophylaxis timing. Postoperative bleeding occurred in 71 (7.5%) patients, with 57 (80.3%) major bleeds, requiring blood transfusion in 48 (67.6%) cases and reintervention in 31 (43.7%) cases. Bleeding extended length-of-stay (median (IQR), 12 (7-27) versus 7 (5-11) days, p < 0.001). Importantly, compared to postoperative chemoprophylaxis, early administration significantly increased the risk of bleeding (10.6% versus 6.3%, RR 1.45, 95% CI 1.05-1.93, p = 0.038) and independently predicted its occurrence.

CONCLUSIONS

The risk of bleeding following elective abdominal visceral resections is substantial and is higher than the risk of clinical VTE. Compared with early chemoprophylaxis, postoperative initiation reduces bleeding risk without an increased risk of clinical VTE.