Lack of consistency in the relationship between asymptomatic DVT detected by venography and symptomatic VTE in thromboprophylaxis trials

The efficacy and safety of low-molecular-weight heparin in patients undergoing knee arthroscopic surgery and anterior cruciate ligament reconstruction

Purpose

To inveatigate how effective LMWH was at preventing venous thromboembolism (VTE), major bleeding events, and minor bleeding events after simple knee arthroscopic surgery and anterior cruciate ligament reconstruction (ACLR).

Methods

We conducted a comprehensive search of PubMed, EMBASE, Cochrane Library, and the CNKI database for potentially eligible articles. The outcomes were evaluated in terms of odds ratio (OR) and the associated 95% confidence intervals (CIs). Meta-analysis was performed using the Stata software and subgroup analyses were performed based on the surgical setting including ACLR and simple knee arthroscopic surgery.

Results

A total of eight studies with 2249 patients and 1794 controls were included in this meta-analysis. In patients undergoing simple knee arthroscopic surgery, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic deep venous thrombosis (DVT), symptomatic pulmonary embolism (PE), symptomatic VTE, and did not increase the risk of major bleeding events, but did have a higher risk of minor bleeding events (OR = 1.95, 95% CI 1.34-2.84, P = 0.000) and a lower risk of asymptomatic DVT (OR = 0.14, 95% CI 0.04-0.53, P = 0.004) in comparison with non-LMWH prophylaxis. In patients undergoing ACLR, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic DVT, symptomatic PE, symptomatic VTE, and did not increase the risk of major bleeding events and minor bleeding events, but did have a lower risk of asymptomatic DVT (OR = 0.43, 95% CI 0.23-0.78, P = 0.006).

Conclusion

When compared to a control group, this meta-analysis found that LMWH had little potential benefit in preventing major VTE (symptomatic VTE, symptomatic DVT, and symptomatic PE) after simple knee arthroscopy and ACLR. As a result, LMWH should not be considered routinely in patients undergoing knee arthroscopic surgery.

Development and validation of a newly developed nomogram for predicting the risk of deep vein thrombosis after surgery for lower limb fractures in elderly patients

Background

Prevention of deep vein thrombosis (DVT) is indispensable in the treatment of lower limb fractures during the perioperative period. This study aimed to develop and validate a novel model for predicting the risk of DVT in elderly patients after orthopedic surgeries for lower limb fractures.

Methods

This observational study included 576 elderly patients with lower limb fractures who were surgically treated from January 2016 to December 2018. Eleven items affecting DVT were optimized by least absolute shrinkage and selection operator regression analysis. Multivariable logistic regression analysis was performed to construct a predictive model incorporating the selected features. C-index was applied to evaluate the discrimination. Decision curve analysis was employed to determine the clinical effectiveness of this model and calibration plot was applied to evaluate the calibration of this nomogram. The internal validation of this model was assessed by bootstrapping validation.

Results

Predictive factors that affected the rate of DVT in this model included smoking, time from injury to surgery, operation time, blood transfusion, hip replacement arthroplasty, and D-dimer level after operation. The nomogram showed significant discrimination with a C-index of 0.919 (95% confidence interval: 0.893-0.946) and good calibration. Acceptable C-index value could still be reached in the interval validation. Decision curve analysis indicated that the DVT risk nomogram was useful within all possibility threshold.

Conclusion

This newly developed nomogram could be used to predict the risk of DVT in elderly patients with lower limb fractures during the perioperative period.

Post-hepatectomy venous thromboembolism: a systematic review with meta-analysis exploring the role of pharmacological thromboprophylaxis

PURPOSE

Patients undergoing hepatectomy are at moderate-to-high risk of venous thromboembolism (VTE). This study critically examines the efficacy of combining pharmacological (PTP) and mechanical thromboprophylaxis (MTP) versus only MTP in reducing VTE events against the risk of hemorrhagic complications.

METHODS

A systematic review of major reference databases was undertaken, and a meta-analysis was performed using common-effects model. Risk of bias assessment was performed using Newcastle-Ottawa scale. Trial sequential analysis (TSA) was used to assess the precision and conclusiveness of the results.

RESULTS

8 studies (n = 4238 patients) meeting inclusion criteria were included in the analysis. Use of PTP + MTP was found to be associated with significantly lower VTE rates compared to only MTP (2.5% vs 5.3%; pooled RR 0.50, p = 0.03, I² = 46%) with minimal type I error. PTP + MTP was not associated with an increased risk of hemorrhagic complications (3.04% vs 1.9%; pooled RR 1.54, p = 0.11, I² = 0%) and had no significant impact on post-operative length of stay (12.1 vs 10.8 days; pooled MD - 0.66, p = 0.98, I² = 0%) and mortality (2.9% vs 3.7%; pooled RR 0.73, p = 0.33, I² = 0%).

CONCLUSION

Despite differences in the baseline patient characteristics, extent of hepatectomy, PTP regimens, and heterogeneity in the pooled analysis, the current study supports the use of PTP in post-hepatectomy patients (grade of recommendation: strong) as the combination of PTP + MTP is associated with a significantly lower incidence of VTE (level of evidence, moderate), without an increased risk of post-hepatectomy hemorrhage (level of evidence, low).

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomized controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in coronavirus disease 2019 (COVID-19). We performed an aggregate data meta-analysis from available trials to quantify effect on nonfatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) vs prophylactic anticoagulation in adults with laboratory-confirmed COVID-19 through 19 January 2022. We used random-effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events (at end of follow-up or discharge) and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (N = 5873). Intensified vs prophylactic anticoagulation was not associated with a mortality reduction up to 45 days (risk ratio [RR], 0.93 [95% confidence interval {CI}, .79–1.10]). There was a possible signal of mortality reduction for non–intensive care unit (ICU) patients, although with low precision and high heterogeneity (5 studies; RR, 0.84 [95% CI, .49–1.44]; I² = 75%). Risk of venous thromboembolism was reduced (RR, 0.53 [95% CI, .41–.69]; I² = 0%), with effect driven by therapeutic rather than intermediate dosing (interaction P = .04). Major bleeding was increased with intensified anticoagulation (RR, 1.73 [95% CI, 1.17–2.56]) with no interaction for dosing and clinical setting.

Conclusions

Intensified anticoagulation has no effect on mortality among hospitalized adults with COVID-19 and is associated with increased bleeding risk. The observed reduction in venous thromboembolism risk and trend toward reduced mortality in non-ICU settings requires exploration in additional RCTs.

Clinical Trials Registration. CRD42021273449 (PROSPERO).

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomised controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in Covid-19. We performed an aggregate data meta-analysis from available trials to quantify effect on non-fatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) versus standard prophylactic dose anticoagulation in adults with laboratory-confirmed Covid-19 through 19 January 2022. The primary efficacy outcome was all-cause mortality at end of follow-up or discharge. We used random effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events, and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (n = 5873). Intensified anticoagulation was not associated with a reduction in mortality for up to 45 days compared with prophylactic anticoagulation: 17.5% (501/2861) died in the intensified anticoagulation group and 18.8% (513/2734) died in the prophylactic anticoagulation group, relative risk (RR) 0.93; 95%CI, 0.79 - 1.10. On subgroup analysis, there was a possible signal of mortality reduction for inpatients admitted to general wards, although with low precision and high heterogeneity (5 studies; RR 0.84; 95% CI, 0.49 - 1.44; I ² = 75%) and not significantly different to studies performed in the ICU (interaction P = 0.51). Risk of venous thromboembolism was reduced with intensified anticoagulation compared with prophylaxis (8 studies; RR 0.53, 95%CI 0.41 - 0.69; I ² = 0%). This effect was driven by therapeutic rather than intermediate dosing on subgroup analysis (interaction P =0.04). Major bleeding was increased with use of intensified anticoagulation (RR 1.73, 95% CI 1.17 - 2.56) with no interaction for dosing and clinical setting.

Conclusion

Intensified anticoagulation has no effect on short term mortality among hospitalised adults with Covid-19 and is associated with increased risk of bleeding. The observed reduction in venous thromboembolism risk and trend towards reduced mortality in non-ICU hospitalised patients requires exploration in additional RCTs.

Summary

In this aggregate data meta-analysis, use of intensified anticoagulation had no effect on short term mortality among hospitalised adults with Covid-19 and was associated with increased risk of bleeding.

Primary thromboprophylaxis in ambulatory cancer patients with a high Khorana score: a systematic review and meta-analysis

Guidelines suggest thromboprophylaxis for ambulatory cancer patients starting chemotherapy with an intermediate to high risk of venous thromboembolism (VTE) according to Khorana score. Data on thromboprophylaxis efficacy in different Khorana score risk groups remain ambiguous. We sought to evaluate thromboprophylaxis in patients with an intermediate- to high-risk (≥2 points) Khorana score and an intermediate-risk score (2 points) or high-risk score (≥3 points) separately. MEDLINE, Embase, and CENTRAL were searched for randomized controlled trials (RCTs) comparing thromboprophylaxis with placebo or standard care in ambulatory cancer patients. Outcomes were VTE, major bleeding, and all-cause mortality. Relative risks (RRs) were calculated in a profile-likelihood random-effects model. Six RCTs were identified, involving 4626 cancer patients. Thromboprophylaxis with direct oral anticoagulants (DOACs) or low molecular weight heparin (LMWH) significantly reduced VTE risk in intermediate- to high-risk (RR, 0.51; 95% confidence interval [CI], 0.34-0.67), intermediate-risk (RR, 0.58; 95% CI, 0.36-0.83), and high-risk patients (RR, 0.45; 95% CI, 0.28-0.67); the numbers needed to treat (NNTs) were 25 (intermediate to high risk), 34 (intermediate risk), and 17 (high risk), respectively. There was no significant difference in major bleeding (RR, 1.06; 95% CI, 0.69-1.67) or all-cause mortality (RR, 0.90; 95% CI, 0.82-1.01). The numbers needed to harm (NNHs) for major bleeding in intermediate- to high-risk, intermediate-risk, and high-risk patients were 1000, -500, and 334, respectively. The overall NNH was lower in DOAC studies (100) versus LMWH studies (-500). These findings indicate thromboprophylaxis effectively reduces the risk of VTE in patients with an intermediate- to high-risk Khorana score, although the NNT is twice as high for intermediate-risk patients compared with high-risk patients.

DOACs vs LMWHs in hospitalized medical patients: a systematic review and meta-analysis that informed 2018 ASH guidelines

Venous thromboembolism (VTE) is a relatively frequent complication in hospitalized patients, especially in those with risk factors. The benefit of using direct oral anticoagulants (DOACs) for prevention is controversial. This systematic review was performed as part of the American Society of Hematology (ASH) guidelines on VTE, developed in partnership with McMaster University. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Epistemonikos were used as data sources from date of inception to November 2019. We included randomized trials in patients hospitalized for an acute medical disease, evaluating any DOACs vs other pharmacological prophylaxis, and included 3 trials with low risk of bias. We analyzed the effects of DOACs vs low-molecular-weight heparins (LMWHs) at 2 different time points: at the end of the short-term treatment phase (both drugs given for the same period of time) and at the end of the extended prophylaxis period (extended DOACs vs a shorter course of LMWHs). We observed that the use of DOACs did not reduce the risk of pulmonary embolism or symptomatic deep venous thrombosis (DVT) in comparison with LMWHs. However, the risk of major bleeding was slightly increased. Additionally, we observed that the benefit of DOACs previously reported was largely based on the reduction of asymptomatic DVT and was not apparent when only symptomatic events were considered. The use of DOACs in hospitalized medical patients slightly increases the risk of major bleeding with no appreciable benefit over LMWHs.

Use of Pre-operative Pharmacologic Venous Thromboembolism Prophylaxis for Robotic Partial Nephrectomy

OBJECTIVE

To determine whether a single dose of preoperative enoxaparin for venous thromboembolism (VTE) prophylaxis impacts rates of thrombotic and bleeding events after robotic partial nephrectomy (RPNx).

METHODS

A retrospective cohort study of RPNx patients from 2009 to 2020 was performed. Clinical characteristics and perioperative outcomes were compared between patients receiving a single dose of preoperative enoxaparin and those who did not. The primary outcome was 30-day hemorrhagic complications (transfusion ≥2 units, embolization, or reoperation for bleeding). Secondary outcomes were 30-day VTE events. Multivariable logistic regression was performed to control for significant differences between groups and to identify predictors of hemorrhagic complications among patients.

RESULTS

Among 945 RPNx procedures, 794 (84%) received preoperative enoxaparin (PPx) and 151 (16%) did not (NPPx). The PPx cohort was older (P = .004), had lower BMI (P = .03), lower ASA class (P = .049), and fewer smokers (P = .03). Warm ischemia time was longer for PPx patients (P < .001). 4.9% and 2.6% of the PPx and NPPx cohorts, respectively, developed postoperative hemorrhagic complications (P = .29). After adjustment for potential covariates, pharmacologic prophylaxis was not associated with 30-day hemorrhagic complications (P = .39). On multivariable regression, longer warm ischemia time (OR 1.05, 95% CI 1.01-1.10, P = .02) and greater tumor size (OR 1.27, 95% CI 1.03-1.56, P = .02) were predictors of hemorrhagic complications. 30-day readmissions, VTE events, and mortality were similar between groups (all P> 0.05).

CONCLUSION

Similar rates of thrombotic and bleeding events occurred between patients receiving pharmacologic prophylaxis and those who did not. Single dose of preoperative enoxaparin did not significantly alter perioperative outcomes after RPNx.

Incidence, prognostic factors, and outcomes of venous thromboembolism in critically ill patients: data from two prospective cohort studies

Background

The objective of this study was to describe the prevalence, incidence, prognostic factors, and outcomes of venous thromboembolism in critically ill patients receiving contemporary thrombosis prophylaxis.

Methods

We conducted a pooled analysis of two prospective cohort studies. The outcomes of interest were in-hospital pulmonary embolism or lower extremity deep vein thrombosis (PE-LDVT), in-hospital nonleg deep vein thrombosis (NLDVT), and 90-day mortality. Multivariable logistic regression analysis was used to evaluate the association between predefined baseline prognostic factors and PE-LDVT or NLDVT. Cox regression analysis was used to evaluate the association between PE-LDVT or NLDVT and 90-day mortality.

Results

A total of 2208 patients were included. The prevalence of any venous thromboembolism during 3 months before ICU admission was 3.6% (95% CI 2.8–4.4%). Out of 2166 patients, 47 (2.2%; 95% CI 1.6–2.9%) developed PE-LDVT and 38 patients (1.8%; 95% CI 1.2–2.4%) developed NLDVT. Renal replacement therapy (OR 3.5 95% CI 1.4–8.6), respiratory failure (OR 2.0; 95% CI 1.1–3.8), and previous VTE (OR 3.6; 95% CI 1.7–7.7) were associated with PE-LDVT. Central venous catheters (OR 5.4; 95% CI 1.7–17.8) and infection (OR 2.2; 95% CI 1.1–4.3) were associated with NLDVT. Occurrence of PE-LDVT but not NLDVT was associated with increased 90-day mortality (HR 2.7; 95% CI 1.6–4.6, respectively, 0.92; 95% CI 0.41–2.1).

Conclusion

Thrombotic events are common in critically ill patients, both before and after ICU admittance. Development of PE-LDVT but not NLDVT was associated with increased mortality. Prognostic factors for developing PE-LDVT or NLDVT despite prophylaxis can be identified at ICU admission and may be used to select patients at higher risk in future randomized clinical trials.

Trial registration

NCT03773939.

Should You Treat This Acutely Ill Medical Inpatient With Venous Thromboembolism Chemoprophylaxis?: Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Venous thromboembolism (VTE), which includes both deep venous thrombosis and pulmonary embolism, is a common and potentially fatal condition. Medical inpatients are at high risk for VTE because of immobility as well as acute and chronic illness. Several randomized trials demonstrated that chemoprophylaxis, or low-dose anticoagulation, prevents VTE in selected medical inpatients. The 2018 American Society of Hematology clinical practice guideline on prophylaxis for hospitalized and nonhospitalized medical patients conditionally recommends chemoprophylaxis for non-critically ill medical inpatients, leaving much to the discretion of the treating physician. Here, 2 experts, a hematologist and a hospitalist, reflect on the care of a woman hospitalized with a rheumatologic disorder. They consider the risks and benefits of chemoprophylaxis, discuss VTE risk stratification, and recommend which patients should receive chemoprophylaxis and with which agents.

Pharmacological thromboprophylaxis to prevent venous thromboembolism in patients with temporary lower limb immobilization after injury: systematic review and network meta-analysis

BACKGROUND

Thromboprophylaxis has the potential to reduce venous thromboembolism (VTE) following lower limb immobilization resulting from injury.

OBJECTIVES

We aimed to estimate the effectiveness of thromboprophylaxis, compare different agents, and identify any factors associated with effectiveness.

METHODS

We undertook a systematic review and network meta-analysis (NMA) of randomized trials reporting VTE or bleeding outcomes that compared thromboprophylactic agents with each other or to no pharmacological prophylaxis, for this indication. An NMA was undertaken for each outcome or agent used, and a series of study-level network meta-regressions examined whether population characteristics, type of injury, treatment of injury, or duration of thromboprophylaxis were associated with treatment effect.

RESULTS

Data from 6857 participants across 13 randomized trials showed that, compared with no treatment, low molecular weight heparin (LMWH) reduced the risk of any VTE (odds ratio [OR]: 0.52; 95% credible interval [CrI]: 0.37-0.71), clinically detected deep vein thrombosis (DVT) (OR: 0.39; 95% CrI: 0.12-0.94) and pulmonary embolism (PE) (OR: 0.16; 95% CrI: 0.01-0.74), whereas fondaparinux reduced the risk of any VTE (OR: 0.13; 95% CrI: 0.05-0.30) and clinically detected DVT (OR: 0.10; 95% CrI: 0.01-0.86), with inconclusive results for PE (OR: 0.40; 95% CrI: 0.01-7.53).

CONCLUSIONS

Thromboprophylaxis with either fondaparinux or LMWH appears to reduce the odds of both asymptomatic and clinically detected VTE in people with temporary lower limb immobilization following an injury. Treatment effects vary by outcome and are not always conclusive. We were unable to identify any treatment effect modifiers other than thromboprophylactic agent used.

A Caprini Risk Score-Based Cost-Effectiveness Analysis of Enoxaparin for the Thromboprophylaxis of Patients After Nonorthopedic Surgery in a Chinese Healthcare Setting

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is an important cause of post-surgery morbidity and mortality. However, it is unclear whether thromboprophylaxis with the low-molecular-weight heparin (LMWH) enoxaparin after non-orthopedic surgery could balance the cost and clinical outcomes or not.

OBJECTIVES

The purpose of this research was to evaluate the cost-effectiveness of enoxaparin for the universal prophylaxis of VTE and associated long-term complications in patients after non-orthopedic surgery compared with no prevention in a Chinese healthcare setting.

METHODS

A decision model, which included both acute VTE and long-term complications, was developed to assess the economic outcomes of the two strategies for patients after non-orthopedic surgery. Quality-adjusted life years (QALYs) and direct medical costs were measured over a 5-year horizon. Incremental cost-effectiveness ratios (ICERs) were calculated.

RESULTS

Compared with no prevention, patients under enoxaparin treatment with Caprini risk scores of 3-4, 5-6, 7-8, and ≥ 9 increased by 0.012, 0.017, 0.034, and 0.102 in QALYs, respectively. The results were either that ICERs of thromboprophylaxis with enoxaparin over no prevention were lower than the thresholds or that thromboprophylaxis with enoxaparin was dominant. For patients with a Caprini risk score ≥ 9, thromboprophylaxis with enoxaparin is dominant across the whole drug use duration range. The sensitivity analysis confirmed the results.

CONCLUSIONS

As the first analysis evaluating the economic outcomes of enoxaparin in patients undergoing general non-orthopedic surgery, this study suggests that thromboprophylaxis with enoxaparin is highly cost-effective compared with no prevention in patients with Caprini risk score ≥ 3.

Effectiveness of Sequential Compression Devices in Prevention of Venous Thromboembolism in Medically Ill Hospitalized Patients: A Retrospective Cohort Study

Objective:

To evaluate the effectiveness of sequential compression devices (SCDs) for venous thromboembolism (VTE) prevention in medically ill hospitalized patients.

Materials and Methods:

Adult patients admitted to a teaching hospital from April 2015 to March 2016 were included. Patients on anticoagulants with or without SCDs were excluded. We analyzed VTE risk, length of hospital stay, and other comorbidities among propensity score-matched patients on SCDs and those without thromboprophylaxis (NONE).

Results:

Among 30,824 patients, 67 patients (0.22%) developed VTE during their hospital stays, with deep vein thrombosis (DVT) in 55 cases and pulmonary embolism (PE) in 12. VTE was seen in 47 out of 20,018 patients on SCDs (41 DVT, 6 PE) and 20 out of 10,819 patients without SCDs (14 DVT, 6 PE). Risk-adjusted analysis showed no significant difference in VTE incidence in the SCD group compared to NONE (odds ratio 0.99, 95% confidence interval 0.57-1.73, p=0.74).

Conclusion:

Compared to the NONE group, SCDs are not associated with decreased VTE incidence during hospital stay.

Venous thromboembolism prophylaxis may cause more harm than benefit: an evidence-based analysis of Canadian and international guidelines

A majority of deep vein thromboses identified in screening studies of hospitalized patients remain clinically insignificant. Guidelines based on these studies markedly overestimate the risk of clinical venous thromboembolism (VTE) and the benefit of heparin prophylaxis. Accordingly, in 2012, the American College of Chest Physicians (ACCP) removed screening studies from the 9th edition of its Antithrombotic and Thrombolytic Therapy guideline (AT9), and downgraded recommendations. Involvement of authors of the 8th edition (AT8) was restricted due to financial and intellectual conflicts of interest. However, the first author of AT8 subsequently wrote a "Getting Started Kit," widely distributed to help Canadian hospitals develop VTE protocols. Based on screening studies reporting asymptomatic VTE, it lacks estimates of the magnitudes of benefit or harm from low molecular weight heparin (LMWH), yet advises prophylaxis in almost all hospitalized patients. Most Canadian hospitals have implemented guidelines based on this kit. Guidelines from the U. K National Institute for Health and Care Excellence and the U.S. Agency for Healthcare Research and Quality recommend a similar approach. However, a critical review of evidence reveals that most hospitalized patients have a risk of clinical VTE equal to or lower than the bleeding risk from LMWH. Most hospitalized patients should not receive LMWH until and unless randomized trials show more benefit than harm. Guidelines recommending liberal LMWH prophylaxis in hospitalized patients are not evidence based and should be critically re-examined.

Efficacy and safety of low-molecular-weight heparin after knee arthroscopy: A meta-analysis

Background

Venous thromboembolism (VTE) is considered a potentially serious complication of knee arthroscopy and leads to conditions such as deep venous thrombosis (DVT) and pulmonary embolism (PE). Low-molecular-weight heparin (LMWH) is widely employed in knee arthroscopy to reduce perioperative thromboembolic complications. However, the efficacy and safety of LMWH in knee arthroscopy remains unclear.

Methods

Seven randomized controlled clinical trials on LMWH in knee arthroscopy were identified and included in this meta-analysis. The main outcomes of the effectiveness (prevention of DVT and PE) and complications (death, major bleeding, and minor bleeding) of LMWH in knee arthroscopic surgery were assessed using Review Manager 5.3 software.

Results

The meta-analysis indicated that LMWH prophylaxis comprised 79% of asymptomatic DVT. No association was found in symptomatic VTE (RR: 0.90; 95% confidence interval [CI]: 0.39–2.08; P = 0.80), symptomatic DVT (RR: 0.79; 95% CI: 0.28–2.23; P = 0.66), symptomatic PE (RR: 1.36; 95% CI: 0.37–4.97; P = 0.64) and major bleeding (RR: 0.70; 95% CI: 0.12–3.95; P = 0.68) risk during LMWH prophylaxis were identified. Death was not reported in these studies. Moreover, there was a lower incidence of minor bleeding (RR: 0.64; 95% CI: 0.49 to 0.83; P = 0.001) in the control group than in the LMWH group.

Conclusion

Compared with the control group, the group treated with LMWH after knee arthroscopy was no association in reducing the symptomatic VTE rate, symptomatic DVT rate or symptomatic PE rate. The symptomatic VTE rate was 0.5% (11/2,166) in the LMWH group versus 0.6% (10/1,713) in the control group. Although the limitations of this meta-analysis cannot be ignored, the results of our study show that LMWH after knee arthroscopy is ineffective. We recommend that LMWH should not be routinely provided for knee arthroscopy.

Trial registration

ClinicalTrials.gov NCT03164746

Assessment of clinically relevant bleeding as a surrogate outcome for major bleeding: validation by meta-analysis of randomized controlled trials

Essentials Surrogacy of clinically relevant bleeding (CRB) for major bleeding has never been validated. Our meta-analysis evaluated CRB surrogacy in trials of new versus traditional anticoagulants. Surrogacy was not validated in orthopedic surgery, venous thromboembolism or atrial fibrillation The difficulty in demonstrating the surrogacy may reflect a lack of homogeneity in its definition SUMMARY: Background Clinically relevant bleeding (CRB), comprising major bleeding and clinically relevant non-major bleeding, has been used as a surrogate for major bleeding in most anticoagulant trials. The validity of this surrogate to estimate trade-off between thrombotic and bleeding events in clinical trials was never assessed. Methods We systematically reviewed randomized phase III trials comparing new anticoagulants with the standard of care for venous thromboembolism prevention following major orthopedic surgery, venous thromboembolism (VTE) treatment, or stroke and systemic embolism prevention in atrial fibrillation (AF), and reporting both major bleeding and CRB rates. The validity of CRB as a surrogate for major bleeding was assessed according to the strength of the association between the relative risks of major bleeding and CRB, measured by the use of R2trial and its 95% confidence interval (CI). Results In the postoperative prophylactic setting (13 studies), major bleeding and CRB rates were 1.12% and 3.56%, respectively, and R2trial was 0.69 (95% CI 0.34-0.93). For acute VTE studies (n = 12), major bleeding and CRB rates were 1.87% and 9.07%; the corresponding R2trial values were 0.28 (95% CI 0.01-0.80) and 0.68 (95% CI 0.09-1.00) when only double-blind studies were considered (n = 7). For AF studies (n = 7; 22 strata), major bleeding and CRB rates were 4.82% and 15.3%, and R2trial was 0.59 (95% CI 0.15-0.82). Conclusion Despite an apparent correlation between CRB and major bleeding in major orthopedic surgery, AF, and double-blind acute VTE studies, the wide CIs suggest that CRB might not be an acceptable surrogate outcome in any of these settings.