Clinical Experiences of High-Risk Pulmonary Thromboembolism Receiving Extracorporeal Membrane Oxygenation in Single Institution / 결핵및호흡기질환

Background@#The main cause of death in pulmonary embolism (PE) is right-heart failure due to acute pressure overload. In this sense, extracorporeal membrane oxygenation (ECMO) might be useful in maintaining hemodynamic stability and improving organ perfusion. Some previous studies have reported ECMO as a bridge to reperfusion therapy of PE. However, little is known about the patients that benefit from ECMO. @*Methods@#Patients who underwent ECMO due to pulmonary thromboembolism at a single university-affiliated hospital between January 2010 and December 2018 were retrospectively reviewed. @*Results@#During the study period, nine patients received ECMO in high-risk PE. The median age of the patients was 60 years (range, 22–76 years), and six (66.7%) were male. All nine patients had cardiac arrests, of which three occurred outside the hospital. All the patients received mechanical support with veno-arterial ECMO, and the median ECMO duration was 1.1 days (range, 0.2–14.0 days). ECMO with anticoagulation alone was performed in six (66.7%), and ECMO with reperfusion therapy was done in three (33.3%). The 30-day mortality rate was 77.8%. The median time taken from the first cardiac arrest to initiation of ECMO was 31 minutes (range, 30–32 minutes) in survivors (n=2) and 65 minutes (range, 33–482 minutes) in non-survivors (n=7). @*Conclusion@#High-risk PE with cardiac arrest has a high mortality rate despite aggressive management with ECMO and reperfusion therapy. Early decision to start ECMO and its rapid initiation might help save those with cardiac arrest in high-risk PE.

Pharmacotherapy for pulmonary embolism: new anticoagulants

Pulmonary embolism is associated with reduced survival and considerable economic burden worldwide. In Korea, the incidence of pulmonary embolism has been gradually increasing. Older individuals are at an increased risk for pulmonary embolism and anticoagulation-related bleeding events. Typically, heparin and vitamin K antagonists are employed to treat pulmonary embolism; however, these agents present numerous limitations. Hence, novel anticoagulants with improved safety and efficacy profiles are urgently needed.Current Concepts: Direct oral anticoagulants (DOACs), including direct thrombin (coagulation factor II) inhibitors and selective inhibitors of coagulation factor Xa, have emerged as alternative agents. Phase III, large-scale clinical trials have revealed that DOACs are non-inferior to standard therapy during initial and long-term treatment of pulmonary embolism, considering the safety profile. Evidence-based clinical guidelines recommend that primary care clinicians employ DOACs over warfarin to achieve anticoagulation.Discussion and Conclusion: For over 70 years, the standard therapy for most patients with pulmonary embolism has involved heparin administration, overlapped and followed by a vitamin K antagonist. Recently developed DOACs against coagulation factor Xa or thrombin might overcome limitations of standard therapy, including the need for injection and regular dose adjustment with laboratory monitoring. These limitations hinder the management of patients with pulmonary embolism and negatively impact the patient’s quality of life. Four DOACs, including apixaban, dabigatran, edoxaban, and rivaroxaban, are currently available for treating pulmonary embolism in Korea, which could simplify the therapeutic strategy.

Incidence of Venous Thromboembolism: The 3 rd Korean Nationwide Study

Background@#The incidence of venous thromboembolism (VTE) has gradually increased in the Korean population. This study aimed to evaluate the annual age- and sex-adjusted incidence rates (ASR) of VTE and anticoagulation trends between 2014 and 2018. @*Methods@#Using the Korean Health Insurance Review and Assessment Service database, we retrospectively identified VTE patients between 2014 and 2018 using both diagnostic and medication anticoagulant codes assigned within 6 months of the initial index event. Anticoagulant patterns were classified as follows: direct oral anticoagulants (DOAC), panticoagulants, warfarin, and mixed anticoagulation regimens. @*Results@#We identified 95,205 patients with VTE (female, 56.8%). The ASR for VTE per 100,000 person-years increased from 32.8 in 2014 to 53.7 cases in 2018 (relative risk of 1.63; 95% confidence interval, 1.6–1.67). The VTE incidence rates were 25 times higher in the ≥ 80 group than in the 30s group. VTE occurred 1.29 times more often in women than in men. The proportion of DOAC prescriptions increased from 40.5% to 72.8%, whereas warfarin prescriptions decreased from 27% to 5.6% in 2014 and 2018. @*Conclusion@#In Korea, the ASRs of VTE continued to increase since 2014, but the rate of increase slowed in 2018. The VTE occurred more often in the elderly and in women. Five years after the introduction of DOACs in 2013, they accounted for 73% of all anticoagulants used to treat VTE.

Electronic Cigarette or Vaping Product Use-Associated Lung Injury: A Case Report

Electronic cigarette (e-cigarette) or vaping product use-associated lung injury (EVALI) has emerged as a social issue as e-cigarette use is rapidly increasing worldwide and is related to many deaths in the United States. To our knowledge, this is the first case report of EVALI in South Korea of a 24-year-old man with acute respiratory symptoms and a history of e-cigarette use. Chest CT revealed diffuse bilateral ground-glass opacities with subpleural sparing, airspace consolidation, and centrilobular micronodules as typical patterns of EVALI with organizing pneumonia and diffuse alveolar damage. Infection was excluded with meticulous laboratory examinations, and the patients’ illnesses were not attributed to other causes. EVALI was diagnosed by meeting the diagnostic criteria with consistent clinico-radiologic findings through a multidisciplinary approach. Radiologists should have good knowledge of EVALI radiologic findings and play a cardinal role in the proper diagnosis and management of EVALI.

Venous thromboembolism associated with combined oral contraceptive use: a single-institution experience

Objective@#Combined oral contraceptives (COCs) are used for various reasons. However, venous thromboembolism (VTE), a significant side effect, can be fatal. This study reports the first case series in Korea involving patients with COC-associated VTE registered at a university hospital. @*Methods@#This study recruited 13 patients diagnosed with COC-associated VTE between June 2006 and May 2018. Risk factors, including age, body mass index, smoking habits, estrogen dosage, type of progestin, and duration of COC use, were evaluated. @*Results@#Among patients with VTE, 9 showed pulmonary embolism (PE) concomitant with deep vein thrombosis (DVT). However, the remaining patients showed DVT (1 patient), PE (1 patient), and cerebral venous thrombosis (2 patients). The median duration between the onset of symptoms and a hospital visit was 3 days, and it sometimes took as long as 32 days. Among the 10 patients with PE, 1 high-risk group and 2 intermediate-high risk groups were treated with tissue plasminogen activators before anticoagulants. There were no cases of recurrence among patients who continued to take anticoagulants for 3 months. @*Conclusion@#These findings emphasize that healthcare professionals who prescribe or dispense COCs to women must inform them of the risk of VTE, including the risk factors, differences in risk depending on the type of progestin present in the product, and pertinent signs and symptoms. Efforts should also be made to inform patients of VTE, even through information campaigns such as brochures. Most importantly, women should remain alert for signs and symptoms of VTE when using COCs.

Venous thromboembolism associated with combined oral contraceptive use: a single-institution experience

Objective@#Combined oral contraceptives (COCs) are used for various reasons. However, venous thromboembolism (VTE), a significant side effect, can be fatal. This study reports the first case series in Korea involving patients with COC-associated VTE registered at a university hospital. @*Methods@#This study recruited 13 patients diagnosed with COC-associated VTE between June 2006 and May 2018. Risk factors, including age, body mass index, smoking habits, estrogen dosage, type of progestin, and duration of COC use, were evaluated. @*Results@#Among patients with VTE, 9 showed pulmonary embolism (PE) concomitant with deep vein thrombosis (DVT). However, the remaining patients showed DVT (1 patient), PE (1 patient), and cerebral venous thrombosis (2 patients). The median duration between the onset of symptoms and a hospital visit was 3 days, and it sometimes took as long as 32 days. Among the 10 patients with PE, 1 high-risk group and 2 intermediate-high risk groups were treated with tissue plasminogen activators before anticoagulants. There were no cases of recurrence among patients who continued to take anticoagulants for 3 months. @*Conclusion@#These findings emphasize that healthcare professionals who prescribe or dispense COCs to women must inform them of the risk of VTE, including the risk factors, differences in risk depending on the type of progestin present in the product, and pertinent signs and symptoms. Efforts should also be made to inform patients of VTE, even through information campaigns such as brochures. Most importantly, women should remain alert for signs and symptoms of VTE when using COCs.

Rifampin-Induced Immune Hemolytic Anemia during Treatment of Pulmonary Tuberculosis in a Patient with Primary Sjogren's Syndrome / 대한수혈학회지

Drug-induced immune hemolytic anemia is a rare disease that occurs in 1 in 1 million individuals of the general population. Rifampin-induced immune hemolytic anemia is caused by drug-dependent antibodies and this can be treated without complication by drug cessation. Herein, we present a case of rifampin-induced immune hemolytic anemia in a patient with primary Sjogren's syndrome (pSS) which occurred during treatment of pulmonary tuberculosis. At admission, the patient's laboratory tests revealed hemolytic anemia and positive direct antiglobulin test result. Since the incidence of autoimmune hemolytic anemia (AIHA) in pSS is reported to be 3 percent, which is higher than that of the general population, differential diagnosis between AIHA and rifampin-induced immune hemolytic anemia was required for planning future anti-tuberculous treatment. We identified rifampin-dependent antibody by drug-induced immune complex test and diagnosed rifampin-induced immune hemolytic anemia. Based on this experience, if rifampin administration is considered in patients with systemic autoimmune disease such as pSS, which has a high incidence of AIHA, we suggest evaluating the presence and the cause of hemolytic anemia at baseline by testing serum lactate dehydrogenase, haptoglobin, and direct and indirect antiglobulin tests before drug administration to promptly identify the cause of hemolysis if hemolytic anemia develops.

Screening and Treatment of Latent Tuberculosis Infection among Healthcare Workers at a Referral Hospital in Korea

BACKGROUND@#Healthcare workers (HCWs) have a high risk of tuberculosis (TB) infection. Since August 2017, Korea has mandated the testing of latent TB infection (LTBI) and recommended treatment from HCWs at medical institutions. However, the acceptance/completion rate and adverse events of LTBI treatment have not been analyzed.@*MATERIALS AND METHODS@#From February to August 2017, we conducted a retrospective study at a referral university hospital in Korea, to screen the interferon-gamma release assay (IGRA) tests conducted for all HCWs for detecting and treating LTBI. HCWs diagnosed with LTBI were offered a 9-month isoniazid (9H), 3-month isoniazid/rifampin (3HR), or 4-month rifampin regimen. We investigated the acceptance/completion rate, adverse events, and causes of discontinuation or change in LTBI medication. A major adverse event was one wherein a patient had any adverse event ≥grade 3 causing LTBI treatment interruption.@*RESULTS@#Of the 1,538 HCWs, 1,379 underwent IGRA testing for LTBI. Among them, 13.6% (187/1,379) tested positive and 73.3% (137/187) received treatment. The overall completion rate was 97.8% (134/137). HCWs were significantly more likely to complete first-line therapy with 3HR than with 9H (91.4% vs. 76.7%, P = 0.02). The most common major adverse event was hepatotoxicity (n = 7), followed by thrombocytopenia (n = 1) and anaphylactic shock (n = 1). Hepatotoxicity and hepatotoxicity (≥ grade 2) were more frequent in 9H than in 3HR (39.5% vs. 17.2%, P = 0.006 and 18.6% vs. 3.7%, P = 0.005, respectively). The median time to hepatotoxicity was 96 days (interquartile range, 20 – 103 days).@*CONCLUSION@#Completion of first-line therapy for LTBI is more likely with 3HR than with 9H. This might be related to the development of hepatotoxicity after around 3 months of treatment. Anaphylactic shock and platelet count should be carefully monitored in those receiving rifampin-containing regimens.

Predictors of Recurrent Venous Thromboembolism after Pulmonary Embolism in Korea / 결핵

No abstract available.

Aggressive Contact Investigation of In-Hospital Exposure to Active Pulmonary Tuberculosis

BACKGROUND: In-hospital detection of newly diagnosed active pulmonary tuberculosis (TB) is important for prevention of potential outbreaks. Here, we report our experience of the aggressive contact investigation strategy in a university hospital in the Republic of Korea after healthcare workers (HCWs), patients, and visitors experience an in-hospital exposure to active pulmonary TB. METHODS: A contact investigation after the unexpected detection of newly diagnosed active pulmonary TB (index patients) was performed in a university hospital from August 2016 to April 2017. Initial and 3-month-post-exposure chest radiographs were advised for all patients, visitors, and HCWs in close contact with the index patients. An additional tuberculous skin test or interferon gamma releasing assay was performed at the time of exposure and 3 months post-exposure in HCWs in close contact with the index patients. RESULTS: Twenty-four index patients were unexpectedly diagnosed with active pulmonary TB after admission to the hospital with unassociated diseases. The median time from admission to TB diagnosis was 5 days (range, 1–22 days). In total, 1,057 people were investigated because of contact with the index patients, 528 of which had close contact (206 events in 157 HCWs, 322 patients or visitors). Three months post exposure, 9 (9.2%) among 98 TB-naïve close contact HCWs developed latent tuberculosis infections (LTBIs). Among the 65 close contact patients or visitors, there was no radiological or clinical evidence of active pulmonary TB. CONCLUSION: An aggressive contact investigation after an unexpected in-hospital diagnosis of active pulmonary TB revealed a high incidence of LTBI among TB-naïve HCWs who had contact with the index patients.

Increased antioxidant activity after exposure of ozone in murine asthma model

BACKGROUND: Ozone is well known as an important component of ambient air pollutants. Ozone can aggravate respiratory symptoms in patients with bronchial asthma, but, not in healthy person. We hypothesized asthma itself may show different response to ozone compared to nonasthma. OBJECTIVE: This study was performed to evaluate the differences of response to ozone between normal and asthmatic mice model in terms of status of oxidant injury and antioxidant activity. METHODS: Three parts per million of ozone was exposed to ovalbumin (OVA)-induced murine asthma model for 3 hours at 3, 7, 14, 21 days after completion of asthma model. Airway responsiveness to methacholine was measured after completion of asthma model. Bronchoalveolar lavage (BAL), protein extraction from lung for Western blot and immunohistochemistry of 4-hydroxy-2-nonenal (4-HNE), proliferating cell nuclear antigen (PCNA), NF-E2 related factor 2 (Nrf-2), and activity of glutathione were performed at before and each ozone exposure day. RESULTS: Airway hyper-responsiveness and increased eosinophils in BAL fluid were observed in asthma model. In asthma model, the expression of 4-HNE already more increased at baseline (without ozone) compared to those in sham model. This increased expression is more enhanced at 3 days after ozone exposure. The expression of PCNA was significantly increased in OVA-model compared to those in sham model. The expression of Nrf-2 was observed at baseline, and 3 and 7 days after exposure ozone in asthma model, but not in sham model. The activity of glutathione increased significantly after exposure of ozone, but not in sham model. CONCLUSION: Murine asthma model has enhanced oxygen toxicity and antioxidant activity response to ozone.

Quality of Anticoagulation with Warfarin in Korean Patients with Atrial Fibrillation and Prior Stroke: A Multicenter Retrospective Observational Study

BACKGROUND AND PURPOSE: The quality of anticoagulation is critical for ensuring the benefit of warfarin, but this has been less well studied in Korean ischemic stroke patients with atrial fibrillation (AF). METHODS: This study retrospectively analyzed the data of patients who had an AF-related ischemic stroke and were treated with long-term warfarin therapy in 16 Korean centers. The quality of warfarin therapy was primarily assessed by the time in therapeutic range [TTR; international normalized ratio (INR), 2.0–3.0] and additionally by the proportion of INR values within the therapeutic range. RESULTS: The long-term warfarin-treated cohort comprised 1,230 patients. They were aged 70.1±9.7 years (mean±SD), 42.5% were female, and their CHA₂DS₂-VASc score was 4.75±1.41. The TTR analysis included 33,941 INR measurements for 27,487 months: per patients, 27.6 (SD, 22.4) INR measurements for 22.4 (SD, 12.9) months. The mean TTR of individual patients was 49.1% (95% confidence interval, 47.9–50.3%), and the TTR quartiles were 64.5%. None of the 16 centers achieved a mean TTR of >60%. Of all INR measurements, 44.6% were within the therapeutic range, 41.7% were 3.0. CONCLUSIONS: In Korean ischemic stroke patients who had AF, the quality of warfarin therapy was low and might be inadequate to effectively prevent recurrent stroke or systemic embolism.

The Perioperative Management of Antithrombotic Therapies Using Enoxaparin

Oral anticoagulant therapy is frequently and increasingly prescribed for patients at risk of arterial or venous thromboembolism (VTE). Although elective surgical or invasive procedures have necessitated temporary interruption of anticoagulants, managing these patients has been performed empirically and been poorly investigated. This study was designed to evaluate the adequacy of perioperative anticoagulation using enoxaparin. This was a retrospective, single-center study that evaluated the efficacy and safety of therapeutic-dose enoxaparin for bridging therapy in patients on long-term warfarin at Soonchunhyang University Hospital in Korea between August 2009 and July 2011. Warfarin was discontinued 5 days before surgery, and enoxaparin was administered twice daily by subcutaneous injection at a dose of 1 mg per kg from 3 days before the procedure to the last dose 24 hours before the procedure. Anticoagulation was restarted if proper hemostasis had been confirmed. There were 49 patients, of whom 25 (51%) were men, and the mean age was 63 years. Thirty-four (69%) received warfarin therapy for VTE, and 9 (18%) for atrial fibrillation. Twenty-nine patients (59%) underwent major surgery and 20 (41%) minor surgery. The mean postoperative duration of enoxaparin was 4 days. No patients had thromboembolic complications through 30 days after the procedure. The overall 30-day mortality rate was 0%. In conclusion, our findings demonstrate that bridging therapy with therapeutic-dose enoxaparin is feasible and associated with a low incidence of major bleeding and no thromboembolic complications. However, the optimal approach to managing patients perioperatively is uncertain and requires further evaluation.

Incidence and Risk Factors of Pneumonia in Hospitalized Patients with Seasonal Influenza A or B / 결핵및호흡기질환

BACKGROUND: Most patients with influenza recover spontaneously or following treatment with an anti-viral agent, but some patients experience pneumonia requiring hospitalization. We conducted a retrospective review to determine the incidence and risk factors of pneumonia in hospitalized patients with influenza A or B. METHODS: A total of 213 patients aged 18 years or older and hospitalized with influenza between January 2012 and January 2015 were included in this study. A reverse-transcriptase polymerase chain reaction assay was used to detect the influenza A or B virus in the patients' sputum samples. We collected demographic and laboratory data, combined coexisting diseases, and radiologic findings. RESULTS: The incidence of pneumonia was higher in patients in the influenza A group compared to those in the influenza B group (68.6% vs. 56.9%), but this difference was not statistically significant. The presence of underlying respiratory disease was significantly associated with pneumonia in the influenza A group (adjusted odds ratio [OR], 3.975; 95% confidence interval [CI], 1.312–12.043; p=0.015). In the influenza B group, the white blood cell count (adjusted OR, 1.413; 95% CI, 1.053–1.896; p=0.021), platelet count (adjusted OR, 0.988; 95% CI, 0.978–0.999; p=0.027), and existence of an underlying medical disease (adjusted OR, 15.858; 95% CI, 1.757–143.088; p=0.014) were all significantly associated with pneumonia in multivariate analyses. CONCLUSION: The incidence of pneumonia was 65.7% in hospitalized patients with influenza A or B. The risk factors of pneumonia differed in hospitalized patients with influenza A or B.

One-year Follow-up of Three Cases of Smoking-related Interstitial Fibrosis / 대한내과학회지

Smoking-related interstitial fibrosis (SRIF) is characterized by marked alveolar septal fibrosis seen as distinct thick collagen bundles, along with emphysema and respiratory bronchiolitis. In 2010, SRIF was deemed a new entity that differed from idiopathic pulmonary fibrosis (IPF) clinically, pathologically, and radiologically. No case of SRIF has been reported in Korea and it is rare worldwide. Here, we report the 1-year follow-up of three cases of SRIF.

Different Responses to Clarithromycin in Patients with Cryptogenic Organizing Pneumonia / 결핵및호흡기질환

Cryptogenic organizing pneumonia (COP) is an idiopathic interstitial pneumonia characterized by a subacute course and favorable prognosis with corticosteroids. However, some patients show resistance to steroids. Macrolides have been used with success in those patients showing resistance to steroids. A few reports showed treatment failure with macrolides in patients with COP who were resistant to steroids. In this report, we described two cases of COP who showed different responses to clarithromycin. One recovered completely, but the other gradually showed lung fibrosis with clarithromycin.

Effect of Rivaroxaban on Fibrinolytic Therapy in Massive Pulmonary Embolism: Two Cases / 결핵및호흡기질환

The risk of dying from a pulmonary embolism (PE) is estimated to be about 30% if inotropic support is required and no cardiopulmonary arrest occurs. Fibrinolysis in massive PE is regarded as a life-saving intervention, unless there is a high risk of bleeding following the use of the fibrinolytic therapy. Rivaroxaban is an oral factor Xa inhibitor, however its anticoagulation effects before or after administration of fibrinolytics in massive PE are still unknown. Two patents were admitted: 61-year-old woman with repeated syncope, and a 73-year-old woman was admitted with dyspnea and poor oral intake. Systemic arterial hypotension with radiologic confirmation led to a diagnosis of massive PE in both patients. Rivaroxaban was administered before in one, and after firbrinolytic therapy in the other. One showed similar efficacy of rivaroxaban with currently used anticoagulants after successful fibrinolysis, and the other one without antecedent administration of the fibrinolytic agent showed unfavorable efficacy of rivaroxaban.

Prevention of Venous Thromboembolism, 2nd Edition: Korean Society of Thrombosis and Hemostasis Evidence-Based Clinical Practice Guidelines

In 2010, we proposed the first Korean Guidelines for the Prevention of Venous Thromboembolism (VTE). It was applicable to Korean patients, by modifying the contents of the second edition of the Japanese guidelines for the prevention of VTE and the 8th edition of the American College of Chest Physicians (ACCP) evidence-based clinical practice guidelines. From 2007 to 2011, we conducted a nationwide study regarding the incidence of VTE after major surgery using the Health Insurance Review and Assessment Service (HIRA) database. In addition, we have considered the 9th edition of the ACCP Evidenced-Based Clinical Practice Guidelines, published in 2012. It emphasized the importance of clinically relevant events as opposed to asymptomatic outcomes with preferences for both thrombotic and bleeding outcomes. Thus, in the development of the new Korean guidelines, three major points were addressed: 1) the new guidelines stratify patients into 4 risk groups (very low, low, moderate, and high) according to the actual incidence of symptomatic VTE from the HIRA databases; 2) the recommended optimal VTE prophylaxis for each group was modified according to condition-specific thrombotic and bleeding risks; 3) guidelines are intended for general information only, are not medical advice, and do not replace professional medical care and/or physician advice.

p53 Expression in a Malignant Mesothelioma Patient during Seven-Year Follow-up / 결핵및호흡기질환

Malignant mesothelioma (MM) is the aggressive tumor of serosal surfaces. There are crude pathogenetic results regarding the biology of MM. Coordinated upregulations of p53 gene expression are shown in malignancies. We believed that there are changes in the p53 expression with transformation from reactive hyperplasia to MM. A 65-year-old male was admitted the hospital because of left pleuritic chest pains in 2004. Chest computed tomography (CT) results showed left pleural effusions with loculation and pleural thickening. Pathologic findings revealed reactive mesothelial hyperplasia. In 2008, the patient again felt left pleuritic chest pains. Chest CT showed progressive thickening of the left pleura. Pathologic diagnosis was atypical mesothelial hyperplasia. In 2011, chest CT showed progressive thickening of his left pleura. He was diagnosed with well-differentiated papillary mesothelioma. Serial change was analyzed by immunohistochemical staining for p53 of pleural tissues. There were no remarkable changes in p53 expressions during the transformation to MM.

Prevention of Venous Thromboembolism in Medical Intensive Care Unit: A Multicenter Observational Study in Korea

Patients admitted to medical intensive care unit (MICU) are at increased risk for venous thromboembolism (VTE); and prophylaxis is recommended. However, the actual range and frequency of VTE prophylaxis administered to MICU patients are not well defined. Patients over 40 yr of age and expected MICU stay of more than 48 hr were eligible for this observational cohort study of 23 MICUs in Korea. Patients already on anticoagulation therapy or those requiring anticoagulation for reasons other than VTE were excluded. Among 830 patients, VTE prophylaxis was given to 560 (67.5%) patients. Among 560 patients, 323 (38.9%) received pharmacoprophylaxis, 318 (38.4%) received mechanical prophylaxis and 81 (9.8%) received both forms of prophylaxis. About 74% of patients in the pharmacoprophylaxis group received low molecular weight heparin and 53% of the patients in the mechanical prophylaxis group used intermittent pneumatic compression. Most of the patients (90%) had more than one risk factor for VTE and the most common risk factor was old age, followed by heart and respiratory failure. In this observational cohort study of 23 MICUs in Korea, 67.5% of patients received thromboprophylaxis. Further studies are needed to clarify the role and efficacy of VTE prophylaxis in Korean critically ill patients.