Rate Of Symptomatic Pulmonary Embolism Research Articles

Clinical and imaging outcomes of OptionELITE vena cava filter placement procedures

ObjectiveWe sought to determine the clinical and imaging outcomes after placement of the OptionELITE inferior vena cava (IVC) filter (Argon Medical Devices, Plano, TX). MethodsThe clinical characteristics and imaging findings of patients who had undergone OptionELITE filter placement at six affiliated hospitals between January 1, 2013 and April 19, 2019, were analyzed. Data were obtained from the Radiology Information System, imaging database, and electronic medical records. The patients were followed up until 1 month after filter removal, death, or the first clinic visit and imaging study after June 1, 2019. ResultsA total of 603 filter placement procedures in 594 patients were evaluated. Of the 603 procedures, 602 were technically successful (99.8%). Of the 594 patients, 356 had presented with acute pulmonary embolism and/or deep vein thrombosis. A total of 189 filters were retrieved from the 191 patients for whom retrieval had been attempted at 4.3 ± 6.3 months (median, 2.5 months) after placement. The 414 filters without removal procedures had been followed up for 14.8 ± 17.7 months (median, 6.9 months). During the follow-up period, 57 patients (9.5%) had developed new or worsening deep vein thrombosis caudal to the filter and 19 (3.2%) had experienced new symptomatic nonfatal pulmonary embolism after filter placement. One filter had migrated and fractured, and another filter had fractured and a strut was lost. Perforation was demonstrated equivocally in 12 (3%) and definitely in 17 (4.3%) of 399 patients with adequate imaging studies available, with penetration into surrounding structures in 13 patients (3.3%). Of 332 patients with adequate imaging studies, 12 (3.6%) had developed substantial IVC thrombosis and 4 (1.2%) had developed IVC occlusion. ConclusionsThe rates of symptomatic pulmonary embolism and filter-related complications were low after OptionELITE IVC filter placement, and filter retrieval, when attempted, was 99% successful.

Enoxaparin titrated by anti-Xa levels reduces venous thromboembolism in trauma patients.

Trauma is a major risk factor for the development of a venous thromboembolism (VTE). After observing higher than expected VTE rates within our center's Trauma Quality Improvement Program data, we instituted a change in our VTE prophylaxis protocol, moving to enoxaparin dosing titrated by anti-Xa levels. We hypothesized that this intervention would lower our symptomatic VTE rates. Adult trauma patients at a single institution meeting National Trauma Data Standard criteria from April 2015 to September 2019 were examined with regards to VTE chemoprophylaxis regimen and VTE incidence. Two groups of patients were identified based on VTE protocol-those who received enoxaparin 30 mg twice daily without routine anti-Xa levels ("pre") versus those who received enoxaparin 40 mg twice daily with dose titrated by serial anti-Xa levels ("post"). Univariate and multivariate analyses were performed to define statistically significant differences in VTE incidence between the two cohorts. There were 1698 patients within the "pre" group and 1406 patients within the "post" group. The two groups were essentially the same in terms of demographics and risk factors for bleeding or thrombosis. There was a statistically significant reduction in VTE rate (p = 0.01) and deep vein thrombosis rate (p = 0.01) but no significant reduction in pulmonary embolism rate (p = 0.21) after implementation of the anti-Xa titration protocol. Risk-adjusted Trauma Quality Improvement Program data showed an improvement in rate of symptomatic pulmonary embolism from fifth decile to first decile. A protocol titrating prophylactic enoxaparin dose based on anti-Xa levels reduced VTE rates. Implementation of this type of protocol requires diligence from the physician and pharmacist team. Further research will investigate the impact of protocol compliance and time to appropriate anti-Xa level on incidence of VTE. Therapeutic/care management, Level IV.

The Timing of Symptomatic Pulmonary Embolism in Patients With Nonwarfarin Anticoagulants Following Elective Primary Total Joint Arthroplasty

BackgroundThe purpose of this study is to investigate the incidence and timing of postoperative, symptomatic pulmonary embolism (PE) in patients receiving nonwarfarin treatment following primary total joint arthroplasty (TJA), to clarify the appropriate duration of postoperative VTE prophylaxis. MethodsWe retrospectively reviewed the medical records of 11,148 patients who underwent primary TJA, including total knee arthroplasty and total hip arthroplasty at our institution between January 2012 and March 2019. The median postoperative day of diagnosis of symptomatic PE and the interquartile range for day of diagnosis were determined. Multivariate Cox proportional hazards modeling was used to test the difference of timing for PE based on demographics and comorbidities. ResultsThe overall 90-day rate of symptomatic PE was 0.71%. The median day of diagnosis for symptomatic PE was 3 days postoperatively (interquartile range, 2-7 days). Factors showed statistical significance on multivariate analysis in association with earlier timing of PE occurrence in patients with atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke. ConclusionThe vast majority of symptomatic PE occurs in the early postoperative period after TJA, and atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke were independent factors affecting the timing of symptomatic PE.

Aspirin Alone Is Not Enough to Prevent Deep Venous Thrombosis After Total Joint Arthroplasty.

Thromboembolic events after total joint arthroplasty are potentially devastating complications. This study evaluated the efficacy of 4 different anticoagulants in preventing deep venous thrombosis and pulmonary embolism after total joint arthroplasty. The demographics and anticoagulant use (warfarin, enoxaparin, and aspirin with and without outpatient mechanical pumps) for patients who underwent primary unilateral total joint arthroplasties performed by a single surgeon from January 2013 to October 2014 were retrospectively reviewed. All patients underwent lower extremity ultrasound at the 3-week postoperative visit. A total of 613 primary unilateral total joint arthroplasties met the study inclusion criteria. There were 288 primary total knee arthroplasties and 325 primary total hip arthroplasties. The patients were 62.2% female, having a mean age of 67.6±10.6 years and a mean body mass index of 30.2±5.9 kg/m2. There were 119 patients in group 1 (aspirin alone), 40 patients in group 2 (aspirin plus pumps), 246 patients in group 3 (warfarin), and 208 patients in group 4 (enoxaparin). The overall 3-week symptomatic and asymptomatic deep venous thrombosis and symptomatic pulmonary embolism rates in the entire cohort were 5.7% and 0.3%, respectively. The venous thromboembolism rate was significantly affected by the anticoagulant of choice (P<.01). Compared with aspirin alone, warfarin decreased the risk of venous thromboembolism (P<.01). Increasing age led to increased risk of venous thromboembolism (P=.05). This study indicated that aspirin chemoprophylaxis alone was not as efficacious as warfarin and enoxaparin in preventing asymptomatic and symptomatic venous thromboembolism found during routine postoperative surveillance with lower extremity ultrasound. Aspirin alone may be inadequate and should be augmented with an outpatient mechanical pump as part of multimodal prophylaxis. [Orthopedics. 2019; 42(1):48-55.].

Perioperative incidence and locations of deep vein thrombosis following specific isolated lower extremity fractures

PurposeTo determine perioperative incidence and locations of deep vein thrombosis (DVT) in injured and uninjured lower extremities following isolated lower extremity fractures (ILEFs). MethodsRetrospective analysis of a prospectively collected data of a consecutive patient series with ILEFs who underwent surgical treatment between September 2014 and September 2017 was performed. Patients’ bilateral lower extremities were screened for DVT with duplex ultrasonography (DUS) before and after surgery. DVT occurrence was analyzed by location of DVT and fracture site. All patients received pharmacologic thromboprophylaxis while hospitalized. Data on demographics, time to surgery, time of DUS examinations, length of hospital stay and symptomatic pulmonary embolism (PE) was collected. Results1825 patients were included in the study. The incidence of symptomatic PE was 1.6%. All patients were screened with DUS of the bilateral lower extremities in a mean of 3.5 days (range: 0–18 days) after injury, and a mean of 3.6 days (range: 1–11 days) after surgery. Preoperative DUS detected DVT in 547 patients (30.0%), including 3.7% of patients with proximal DVT. 792 patients (43.4%) were found to have a DVT postoperatively, but only 6.2% of patients with proximal DVT. Proximal DVT was detected postoperatively of the represented fractures: 6.5% of the hip, 14.5% of the femoral shaft, 4.5% of the tibial plateau, 4.6% of the tibial shaft, 1.7% of the patellar, and 2.0% of the peri-ankle. Interestingly, the rate of DVT in an uninjured lower limb was significantly higher postoperatively compared to preoperatively (16.4% vs. 4.9%), however, only 0.2% of patients had proximal DVT. ConclusionsWhile the perioperative incidence of overall DVT is high following ILEFs, the majority were distal DVT, and the rate of symptomatic PE was low. Femoral shaft fractures were associated with the highest incidence for proximal DVT. The incidence was lower in more distal fractures. The majority of patients diagnosed with DVT postoperatively had already shown symptoms of DVT prior to surgery. DVT can occur in both the injured and uninjured leg, with an obviously higher incidence in the injured leg. The incidence of proximal DVT in an uninjured leg is rare.

A Systematic Review and Meta-analysis Comparing Anticoagulation versus No Anticoagulation and Shorter versus Longer duration of Anticoagulation for Treatment of Isolated Distal Deep Vein Thrombosis.

AbstractIsolated distal deep vein thrombosis (DVT) represents an important clinical problem but there is no consensus regarding its management. The aim of this review was to evaluate the safety, efficacy, and shorter versus longer duration of anticoagulation in patients with isolated distal DVT. A systematic search was conducted using MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systemic Reviews. Studies reporting rates of symptomatic pulmonary embolism (PE), recurrent DVT, proximal extension, and/or major bleeding were included. Fourteen studies (six randomized controlled trials, eight cohorts) involving 2,918 patients met the eligibility criteria (with a total of 13 meeting criteria for the meta-analysis). Compared with no anticoagulation, anticoagulation was associated with a significant reduction in proximal extension (odds ratio [OR]: 0.29; 95% confidence interval [CI]: 0.13–0.67; p &lt; 0.004), recurrent DVT (OR: 0.16; 95% CI: 0.04–0.65; p = 0.01), and the composite end-point of proximal extension/PE (OR: 0.34; 95% CI: 0.16–0.72; p = 0.005); however, no significant differences in PE (OR: 0.47; 95% CI: 0.17–1.34; p = 0.16) or major bleeding (OR: 1.49; 95% CI: 0.33–6.86; p = 0.60) were observed. Anticoagulation for a longer duration (≥8 vs. ≤6 weeks) was associated with a significant reduction in proximal extension (OR: 0.23; 95% CI: 0.11–0.48; p &lt; 0.001) but not for other outcomes.

Les complications thromboemboliques post-traumatique : incidence, facteurs de risques, physiopathologie et prévention

Venous thromboembolism (VTE) remains a major challenge in critically ill patients. Subjects admitted in intensive care unit (ICU), in particular trauma patients, are at high-risk for both deep vein thrombosis (DVT) and pulmonary embolism (PE). The rate of symptomatic PE in injured patients has been reported previously ranging from 1 to 6%. The high incidence of posttraumatic venous thromboembolic events is well known. In fact, major trauma is a hypercoagulable state. Several factors placing the individual patient at a higher risk for the development of DVT and PE have been suggested: high ISS score, meningeal hemorrhage and spinal cord injuries have frequently been reported as a significant risk factor for VTEs after trauma. Posttraumatic pulmonary embolism traditionally occurs after a period of at least 5 days from trauma. The prevention can reduce the incidence and mortality associated with the pulmonary embolism if it is effective. There is no consensus is now available about the prevention of venous thromboembolism in trauma patients.

Les complications thromboemboliques post-traumatique : incidence, facteurs de risques, physiopathologie et prévention

Venous thromboembolism (VTE) remains a major challenge in critically ill patients. Subjects admitted in intensive care unit (ICU), in particular trauma patients, are at high-risk for both deep vein thrombosis (DVT) and pulmonary embolism (PE). The rate of symptomatic PE in injured patients has been reported previously ranging from 1 to 6%. The high incidence of posttraumatic venous thromboembolic events is well known. In fact, major trauma is a hypercoagulable state. Several factors placing the individual patient at a higher risk for the development of DVT and PE have been suggested: high ISS score, meningeal hemorrhage and spinal cord injuries have frequently been reported as a significant risk factor for VTEs after trauma. Posttraumatic pulmonary embolism traditionally occurs after a period of at least 5 days from trauma. The prevention can reduce the incidence and mortality associated with the pulmonary embolism if it is effective. There is no consensus is now available about the prevention of venous thromboembolism in trauma patients.

Pulmonary Embolism Rates Following Total Hip Arthroplasty With Prophylactic Anticoagulation: Some Pulmonary Emboli Cannot Be Avoided

BackgroundA symptomatic pulmonary embolism (PE) after total joint arthroplasty has been described as a “never event.” Despite potent anticoagulants and improvements in patient care, PE continues to occur following total hip arthroplasty (THA). This study evaluates symptomatic PE rates over time in THA patients enrolled in multicenter randomized clinical trials (RCTs) assessing the efficacy of venous thromboembolism prophylaxis regimens. MethodsThe MEDLINE and Cochrane Central Register of Controlled Trials were searched to identify clinical trials assessing prophylactic anticoagulation in patients undergoing THA between January 1995 and December 2015. Inclusion criteria consisted of RCTs evaluating prophylactic anticoagulation in patients undergoing THA. A random effect model was used to combine PE rates across studies. ResultsA total of 21 studies (34,764 patients) were included. Patients were administered low molecular weight heparin (13,590 patients), oral factor Xa inhibitors (6609 patients), oral direct thrombin inhibitors (5965 patients), indirect factors Xa/IIa inhibitors (3444 patients), aspirin (2427 patients), and warfarin (489 patients). Mobile compression was used in 199 patients, and placebo was used in 2041 patients. Across all included studies, the estimated PE rate was 0.21% (95% confidence interval: 0.13%, 0.32%). Between 1997 and 2013, the proportion of PEs did not change in regression analysis. ConclusionAlthough the PE rate was low, it was consistent throughout the 17 years spanning these RCTs, which excluded patients with significant morbidity. These results suggest that even healthy THA patients receiving aggressive anticoagulation still have a risk for PE, and the “never event” designation requires reassessment.

Outcome during and after anticoagulant therapy in cancer patients with incidentally found pulmonary embolism.

Current guidelines suggest treating cancer patients with incidental pulmonary embolism comparably to patients with symptomatic pulmonary embolism.We used the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry to compare the rate of major bleeding and symptomatic pulmonary embolism during the course of anticoagulation and after its discontinuation in cancer patients with incidental pulmonary embolism.As of March 2016, 715 cancer patients with incidental pulmonary embolism had been enrolled in RIETE. During the course of anticoagulant therapy (mean 235 days), the rate of major bleeding was higher than the rate of symptomatic pulmonary embolism (10.1 (95% CI 7.48-13.4) versus 3.17 (95% CI 1.80-5.19) events per 100 patient-years, respectively), and the rate of fatal bleeding was higher than the rate of fatal pulmonary embolism (2.66 (95% CI 1.44-4.52) versus 0.66 (95% CI 0.17-1.81) deaths per 100 patient-years, respectively). After discontinuing anticoagulation (mean follow-up 117 days), the rate of major bleeding was lower than the rate of symptomatic pulmonary embolism (3.00 (95% CI 1.10-6.65) versus 8.37 (95% CI 4.76-13.7) events per 100 patient-years, respectively); however, there were no differences in the rate of fatal events at one death each.The risk/benefit ratio of anticoagulant therapy in cancer patients with incidental pulmonary embolism is uncertain and must be evaluated in further studies.

Does intermittent pneumatic compression increase the risk of pulmonary embolism in deep venous thrombosis after joint surgery?

The present study aimed to identify the incidence and risk factors of symptomatic pulmonary embolism and evaluate the safety of early intermittent pneumatic compression application in patients with deep venous thrombosis (DVT) after joint surgery. A total of 144 patients with DVT undergoing joint surgery were divided into two groups according to the appearance of symptomatic pulmonary embolism. Venography and computed tomographic pulmonary angiography were utilized as the assessment methods. The total incidence of symptomatic pulmonary embolism was 0.39% after joint surgery. However, the prevalence increased to 3.5% when computed in patients with DVT. Patients with symptomatic pulmonary embolism were older than those without symptomatic pulmonary embolism (69 ± 4 versus 61 ± 15 years, P = 0.04). The occurrence rate of symptomatic pulmonary embolism in patients with diabetes mellitus was much higher than that in the patients without diabetes mellitus (40.0% versus 8.6%, respectively, P = 0.02). The prevalence of symptomatic pulmonary embolism after joint surgery in patients with DVT was not distinctive. Increased age and diabetes mellitus put patients with DVT at risk of suffering symptomatic pulmonary embolism after joint surgery. In addition, early postoperative application of intermittent pneumatic compression was safe in these patients.

Venous thromboembolism after radical cystectomy: Experience with screening ultrasonography

ObjectivesTo detect the incidence of immediate postoperative deep vein thrombosis (DVT) using screening lower extremity ultrasonography (US) in patients undergoing radical cystectomy (RC) and to determine the rate of symptomatic pulmonary embolism (PE) after RC and identify risk factors for venous thromboembolic (VTE) events in a RC population. Patients and methodsWe performed a retrospective review of prospective data collected on patients who underwent RC between July 2008 and January 2012. These patients underwent screening US at 2/3days after RC to determine the rate of asymptomatic DVT. A chart review was completed to identify those who had a symptomatic PE. Univariate and multivariable analysis was used to identify risk factors associated with DVT, PE and total VTE events. ResultsIn all, 221 patients underwent RC and asymptomatic DVT was identified in 21 (9.5%) on screening US. Nine (4.5%) developed symptomatic PE at a median of 9days, of which no patients had positive lower extremity US postoperatively. Increased length of hospital stay, increased estimated blood loss, and lower body mass index were linked to risk of PE, and only a previous history of DVT was associated with postoperative DVT. ConclusionPatients who undergo RC are at high-risk for thromboembolic events and multimodal prophylaxis should be administered. Clinicians should be especially vigilant in those who demonstrate factors associated with higher risk for VTE events.

Fatal pulmonary embolism after arthroscopic rotator cuff repair: a case series

pulmonary embolism (PE) is a rare and serious complication of arthroscopic orthopaedic surgery. Currently there is great paucity in the literature regarding PE events following arthroscopic rotator cuff (ARCR) surgery. The purpose of this case series was to (1) report our known incidence rate of symptomatic PE following ARCR for a single surgeon and (2) describe five cases of pulmonary embolism following ARCR, detailing patient medical history and potential perioperative risk factors. the number of PE events were queried retrospectively from the institutional database with the ICD-9 code 415.1 within a 10 year time frame (2003-2013). Cases of PE identified by ICD-9 query were reviewed for type of procedure, postoperative day of event, and surgeon. Only patients with a confirmed diagnosis by computed tomography (CT) scan or post-mortem exam, were included in this study. Patient medical records belonging to affected patients were ordered and reviewed by a single investigator. Pre, intra, and postoperative information was obtained and summarized. 5 cases of PE were identified, two of which were fatal. All events occurred in the perioperative period following ARCR. The 10 year incidence rate for PE following ARCR was 0.89%. Medical record review revealed significant risk factors for these patients when compared to current VTE prophylactic guidelines. our ten year incidence rate of PE following arthroscopic shoulder surgery and ARCR was 0.25 and 0.89% respectively. These rates were found to be considerably higher than reported rates of PE in the general population and following arthroscopic shoulder surgery. In addition, our methods failed to detect subclinical PE events, resulting in the likelihood of this value to be an underestimate of the true incidence. Medical record review revealed risk factors which would qualify patients for chemoprophylaxis under certain guidelines, however, the validity of available risk stratification methods continue to be a topic of debate. Level IV; case series.

The Rate and Mortality of Postoperative Venous Thromboembolism of Moderate Risk Surgery in Asian Patients without Thrombo‐prophylaxis: Systematic Review with Meta‐analysis

The general gynecologic and neurologic surgeries are regard as carrying moderate risk for postoperative venous thromboembolism (VTE). This review analyzed the postoperative VTE rate of these surgeries in Asia. Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography, ultrasonography, or radionucleotide scan; and no thromboprophylaxis. The pooled proportion was back calculated from Freeman-Tukey variant transformation, using a random effect model. Medline, EMBASE, Cochrane Library, and KoreaMed were searched. Fourteen studies (total population of 1,625) published from 1974 to 2008 were included. In general surgery, the pooled rate of all-sites proximal, isolated distal DVT was 13.4, 2.1, and 11.8 % (radionucleotide scan). The cancer patients carried a higher all-sites DVT rate (19.7 % radionucleotide scan and 17.4 % ultrasound). Gynecologic and neurologic surgery had 3.1 % (ultrasound) and 3.8 % (radionucleotide scan) all-sites DVT rate. For general, gynecologic, and neurologic patients, the pooled rates of symptomatic DVT were 1.5, 0.2, and 1.0 % respectively. The pooled rate of symptomatic pulmonary embolism (PE) was 0.4 % for general surgery. No patients died from PE (pooled rate 0.2 %); however, a single PE death was reported in the excluded study. Postoperative symptomatic VTE was relatively low in Asia. Further study is required to stratify VTE risk and the need for thromboprophylaxis in individual patients.

A Prospective Comparison of Warfarin to Aspirin for Thromboprophylaxis in Total Hip and Total Knee Arthroplasty

Current orthopedic practice requires consideration of contradictory recommendations regarding pulmonary embolism (PE) prevention among patients undergoing total hip arthroplasty (THA) and knee joint arthroplasty (TKA). A total of 696 consecutive patients underwent elective THA or TKA. Two hundred eighty-one patients received PE risk stratification per American Academy of Orthopaedic Surgeons guidelines. Of these patients, 152 standard-risk patients received aspirin, and 129 elevated-risk patients received warfarin. The comparator group of 415 patients received American College of Chest Physicians–recommended warfarin without PE risk stratification. Primary study outcomes were symptomatic PE, deep venous thrombosis, major bleeding, and death. The rate of symptomatic PE and venous thromboembolism among standard-risk group patients receiving aspirin was greater than the comparator group (4.6% vs 0.7% and 7.9% vs 1.2%, respectively). Most events (16/18) occurred among patients undergoing TKA. Patients with total joint arthroplasty at standard risk for PE receiving aspirin had a higher rate of symptomatic PE and venous thromboembolism than did patients receiving anticoagulation.

Fertility rates and gross national incomes per capita

Current guidelines suggest treating cancer patients with incidental pulmonary embolism comparably to patients with symptomatic pulmonary embolism. We used the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry to compare the rate of major bleeding and symptomatic pulmonary embolism during the course of anticoagulation and after its discontinuation in cancer patients with incidental pulmonary embolism. As of March 2016, 715 cancer patients with incidental pulmonary embolism had been enrolled in RIETE. During the course of anticoagulant therapy (mean 235 days), the rate of major bleeding was higher than the&nbsp;rate of symptomatic pulmonary embolism (10.1 (95% CI 7.48–13.4) <i>versus</i> 3.17 (95% CI 1.80–5.19) events per 100 patient–years, respectively), and the rate of fatal bleeding was higher than the rate of fatal pulmonary embolism (2.66 (95% CI 1.44–4.52) <i>versus</i> 0.66 (95% CI 0.17–1.81) deaths per 100 patient-years, respectively). After discontinuing anticoagulation (mean follow-up 117 days), the rate of major bleeding was lower than the rate of symptomatic pulmonary embolism (3.00 (95% CI 1.10–6.65) <i>versus</i> 8.37 (95% CI 4.76–13.7) events per 100 patient-years, respectively); however, there were no differences in the rate of fatal events at one death each. The risk/benefit ratio of anticoagulant therapy in cancer patients with incidental pulmonary embolism is uncertain and must be evaluated in further studies.

Thromboembolism after total hip replacement

Total hip replacement (THR) is an elective procedure associated with an increased risk of venous thromboembolic events such as deep vein thrombosis (DVT) and pulmonary embolism (PE). Routine prophylaxis against thromboembolic events after THR remains the standard of care in the United States. Thrombus formation is associated with Virchow's triad (stasis, endothelial injury, and a hypercoagulable state) and occurs during the course of THR surgery. The choice of anesthesia and operative technique can affect the incidence of thromboembolic events. Warfarin and various low-molecular-weight heparins have been studied extensively in randomized trials and in large cohort studies. Both agents have been demonstrated to provide safe and effective prophylaxis, but they also have certain limitations. Recently, aspirin has received increased attention as a potential prophylaxis agent. Although aspirin appears to reduce symptomatic PE rates, further studies of this drug in randomized control trials are necessary. There is no consensus on the optimal length of postoperative thromboprophylaxis, although the occurrence of late thromboembolic events is recognized. Postdischarge prophylaxis is safe and effective and is recommended in this era of short hospital stays. Routine ultrasound surveillance appears to be unreliable and does not appear to reduce the risk of subsequent venous thromboembolic events in patients already receiving thromboprophylaxis. At the present time, all THR patients require prophylaxis to prevent symptomatic thromboembolic events. Balancing the risk and benefits of each prophylactic agent or a particular prophylactic regimen, the individual surgeon must choose and meticulously implement the method of prophylaxis that best fits his/her practice and patient population.

The efficacy of prophylaxis with low-dose warfarin for prevention of pulmonary embolism following total hip arthroplasty.

The selection of a prophylaxis regimen and its implementation have been influenced considerably by the decreased duration of hospital stays and the pressures of cost containment. The purpose of the present study was to determine the rate of symptomatic pulmonary embolism both before and after discharge, the number of days required to achieve an adequate level of anticoagulation, and the complications associated with the use of low-dose warfarin after total hip arthroplasty. Between 1987 and 1993, 1099 primary and revision total hip arthroplasties were performed in 940 patients who received low-dose warfarin for prophylaxis against thromboembolic disease. The average duration of prophylaxis was fifteen days (range, one to twenty-nine days). The target level of anticoagulation (as indicated by a prothrombin time of fourteen to seventeen seconds) was achieved an average of three days (range, one to sixteen days) after the operation. The level of anticoagulation was lower than the target range at the time of discharge after 257 total hip arthroplasties (23.4 per cent), and the target level was never achieved during the period of hospitalization after fifty-four such procedures (4.9 per cent). Twelve total hip arthroplasties were associated with a symptomatic pulmonary embolism; the over-all prevalence of this complication therefore was 1.1 per cent (95 per cent confidence interval, 0.4 to 1.9 per cent). Four pulmonary emboli were diagnosed before discharge and eight, after discharge. A fatal pulmonary embolism occurred after one procedure (0.1 per cent). Patients who had a history of symptomatic venous thromboembolic disease had a significantly increased risk of symptomatic pulmonary embolism after total hip arthroplasty (p = 0.001, Fisher exact test). A major bleeding episode occurred after thirty-two total hip arthroplasties (2.9 per cent). Patients who had a prothrombin time of more than seventeen seconds had a significantly increased risk of hematoma formation (p = 0.003, chi-square analysis). Prophylaxis with low-dose warfarin is safe and effective for the prevention of pulmonary embolism after total hip arthroplasty.