Patients' perception about risks and benefits of antithrombotic treatment for the prevention of venous thromboembolism (VTE) after orthopedic surgery: a qualitative study

Background

The 9th edition of the American College of Chest Physicians’ Antithrombotic Therapy and Prevention of Thrombosis guidelines emphasize the importance of considering the risk–benefit ratio of “patient-important” outcomes. However, little is known about patients’ perception and understanding regarding the different outcomes of antithrombotic treatment after orthopedic surgery, and the factors that influence their decision to use these treatments. Using a series of semi-structured interviews, we explored patients’ understanding and perception concerning the benefits and risks of antithrombotic treatment for the prevention of venous thromboembolism (VTE) after joint replacement surgery.

Methods

A series of semi-structured interviews were conducted with patients who had undergone knee or hip replacement surgery at a tertiary care hospital (Brigham and Women’s Hospital, Boston, MA) in 2014. Discussions were recorded and transcribed. Two investigators independently coded and analyzed the data to identify important themes and concepts using the constant comparative method.

Results

Of 64 patients who were invited, 12 patients (19 %) completed the interviews. The majority of patients (92 %) were aware of the benefits of antithrombotic therapy for reducing the risk of blood clots, while less than half of them had a clear understanding of deep vein thrombosis and pulmonary embolism. While all patients were aware of risk of minor bleeding, only 6 patients (50 %) considered the risk of major bleeding as a possible side effect of antithrombotic treatment. Overall, patients perceived bleeding as a less important outcome than a thrombotic event. The lack of awareness about the risk of major bleeding, the assumption that a short-term exposure would not meaningfully affect bleeding risk, and the assumption that bleeding is a controllable event influenced their perception. Most patients (83 %) stated that their decision to use antithrombotic medications was mainly based on the trust in their physician’s expertise.

Conclusions

Patients perceived thrombotic events as more important outcomes than bleeding events. Patients’ understanding of thrombotic and bleeding events varies and may play a key role in their preferences. The majority of patients stated that trust in their physician’s expertise had a large influence on their decision to use antithrombotic medications.

Preoperative dosing of low-molecular-weight heparin in hepatopancreatobiliary surgery

BACKGROUND

Venous thromboembolism is a common cause of morbidity. Guidelines recommend perioperative thromboprophylaxis, but clinicians remain cautious of bleeding after major oncologic resections.

METHODS

Retrospective analysis of a single institution's prospective hepatopancreatobiliary database was performed for patients undergoing surgery between January 2010 and February 2013. A total of 223 patients received postoperative thromboprophylaxis and 93 patients were dosed with low-molecular-weight heparin (LMWH) preoperatively.

RESULTS

Two hundred twenty-three patients were analyzed; 50.6% underwent pancreatic and 49.3% underwent liver resection. There were no differences in previous venous thromboembolism (3.8% vs 3.3%; P = .56) or preoperative venous thromboembolism scores (5.74 vs 5.67; P = .82). Estimated blood loss (537 mL vs 592 mL; P = .54), transfusions (25.4% vs 30.4%; P = .25), and complications (52.3% vs 43.5%; P = .12) were equivalent. Incidence of thromboembolic events was lower (6.1% vs 1.1%; P = .05); however, bleeding requiring intervention was increased in the preoperative LMWH group (10.9% vs 3.1%; P = .026).

CONCLUSIONS

Caution must be exercised when using LMWH, as bleeding remains a concern for oncologic hepatopancreatobiliary surgery.

Incidence of postoperative venous thromboembolism after laparoscopic versus open colorectal cancer surgery: a meta-analysis

The objective of this study was to systematically compare the incidence of postoperative venous thromboembolism (VTE; deep vein thrombosis and/or pulmonary embolism) in patients with colorectal cancer after laparoscopic surgery and conventional open surgery. A systematic search of Medline, EMBASE, and the Cochrane Central Register of Controlled Trials was conducted. Eleven randomized control trials involving 3058 individuals who reported VTE outcomes were identified, of whom 1677 were treated with laparoscopic therapy and 1381 underwent open surgery. The combined results of the individual trials showed no statistically significant difference in the odds ratio for overall VTE (odds ratio 0.64, 95% confidence interval, 0.33-1.23, P=0.18), as well as in subgroups of deep vein thrombosis and anticoagulant prophylaxis between these 2 approaches. In conclusion, laparoscopic resection could achieve similar outcomes in terms of the incidence of VTE, which are associated with long-term benefits of the patients.

Timing and perioperative risk factors for in-hospital and post-discharge venous thromboembolism after colorectal cancer resection

INTRODUCTION

We postulated that the risk of venous thromboembolic disease (VTE) may persist after discharge and tested this hypothesis in patients undergoing colorectal resection for cancer.

METHODS

The American College of Surgeons National Surgery Quality Improvement Program database was queried for patients undergoing colorectal resections for cancer from 2005 to 2009. The outcome analyzed was a 30-day deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Multivariable forward stepwise regression was used to identify independent predictors of VTE.

RESULTS

The database contained 21 943 colorectal cancer resections. The 30-day DVT rate was 1.4% (306 of 21 943), 29% (89 of 306) were diagnosed post-discharge. The 30-day PE rate was 0.8% (180 of 21 943), 33% (60 of 180) was diagnosed post-discharge, the combined DVT/PE rate was 2.0% (446 of 21 943). The median time to diagnosis of VTE was 9 days (interquartile range 4-16) after surgery. Post-discharge VTE rates in patients with length of stay (LOS) less than 1 week (0.6%) were similar to patients with LOS greater than 1 week (0.7%, Fisher exact P not significant). Independent risk factors for post-discharge VTE were preoperative steroid use for chronic condition (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.51-5.57, P = .001) and preoperative systemic inflammatory response syndrome (OR 2.26, 95% CI 1.24-4.10, P = .008).

CONCLUSIONS

Diagnosis of almost one third of postoperative VTE in this patient population occurred after discharge. The duration of the prothrombotic stimulus of surgery is not well defined, and patients with malignancy are at high risk of VTE; thromboprophylaxis after discharge should be considered for these patients.

Platelet-dense granule deficiency causes postoperative hemorrhage in patients receiving enoxaparin: a novel observation with dramatic clinical implications

BACKGROUND

Inherent hemorrhage risk has impeded the universal adoption of low-molecular-weight heparin (LMWH) for venous thromboembolic prophylaxis in surgical patients. Coagulation pathway parameters and platelet numbers routinely are evaluated preoperatively; scant attention has been directed toward evaluation of platelet function. We hypothesized that administration of LMWH may unmask latent platelet dysfunction and result in postoperative hemorrhage.

METHODS

Postoperative hemorrhage occurred in 15 (3.5%) of 423 consecutive patients undergoing laparoscopic gastric bypass. All patients received LMWH (enoxaparin, 40 mg) preoperatively. Hematologic evaluation included measurement of von Willebrand's factor level and activity, factor VIII level, and electron microscopic enumeration of platelet-dense granules.

RESULTS

All patients had normal preoperative platelet counts and coagulation profiles. Ten patients underwent hematologic evaluation: coagulation pathway parameters were normal in all; however, all patients had a markedly decreased number of platelet-dense granules.

CONCLUSIONS

Platelet-dense granule deficiency may cause postoperative hemorrhage in patients receiving LMWH.

Venous thromboembolism in elective operations: balancing the choices

BACKGROUND

Venous thromboembolism (VTE) is a recognized cause of morbidity and mortality in hospitalized patients and is reported to account for 250,000 deaths annually. Recent shifts in prophylaxis administration are occurring among surgical specialty groups after observing a lower rate of VTE among patients undergoing elective operation. We report the incidence of VTE from 3 sources to provide an estimate of the true risk of the complication in elective surgery.

METHODS

Data from the Surgical Care Improvement Project (SCIP), University HealthSystem Consortium (UHC), and Kentucky Cabinet for Health and Family Services (CHFS) databases were queried for 2004 for the same operative patient groups.

RESULTS

Of 5,285 operations performed within SCIP 2004, the incidences of deep venous thrombosis (DVT) and pulmonary embolus (PE) were 0.4% and 0.3%, respectively, with no reported deaths. Of 966,474 operations recorded in the UHC 2004 data, rates of DVT and PE were 1.2% and 0.5%, respectively. The incidence rates of DVT and PE among 20,563 patients in the CHFS 2004 database were 0.5% and 0.3%, respectively, and included 3 deaths.

CONCLUSION

VTE and associated mortality rates are extremely low in these 3 large data sources. We believe patients will benefit from an ongoing assessment of real need and complications of carefully risk-adjusted VTE prophylaxis.