1
|
Bilyalova G, Iskalieva S, Baibusunova A, Boshanova A. Acute inferior vena cava thromboembolism in pregnancy. BMJ Case Rep 2024; 17:e258667. [PMID: 38232997 PMCID: PMC10806888 DOI: 10.1136/bcr-2023-258667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024] Open
Abstract
A multigravida in her late 20s was diagnosed with inferior vena cava thrombosis (IVCT) and PE at 26 weeks of pregnancy after a routine prenatal care visit. The patient denied any diseases that could cause IVCT, as well as the presence of any symptoms. Progressive thrombocytopenia was diagnosed in the period until the implantation of the inferior vena cava filter (IVCF). Due to a rupture of foetal membranes and chorioamnionitis, labour was induced at 32 weeks of pregnancy. The IVCF remained in place and anticoagulants were continued through the postpartum period for up to 6 months.
Collapse
Affiliation(s)
- Gulshat Bilyalova
- Obstetrics & Gynecology, Astana Medical University, Astana, Kazakhstan
| | - Saira Iskalieva
- Obstetrics & Gynecology, Astana Medical University, Astana, Kazakhstan
| | - Aida Baibusunova
- Obstetrics & Gynecology, Astana Medical University, Astana, Kazakhstan
| | - Assel Boshanova
- Obstetrics & Gynecology, Astana Medical University, Astana, Kazakhstan
| |
Collapse
|
2
|
Zhang L, Hu WP, Zhang H, Xia SB, Wang HF, Song C, Lu QS. Retrievable Inferior Vena Cava Filter Trapped Embolus: A Risk Factor of Detachment of Thrombus Analysis Based on a Multicenter Prospective Observational Study. J Endovasc Ther 2023:15266028231205718. [PMID: 37882181 DOI: 10.1177/15266028231205718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
PURPOSE Up to now, the indications of inferior vena cava filter placement still remain controversial in the academic field. The aim of this study was to determine the risk factors of detachment of thrombus and to evaluate the necessity of inferior vena cava filter placement to prevent fatal pulmonary embolism. MATERIALS AND METHODS A total of 2892 patients participated in the multicenter prospective observational study from January 1, 2018, to December 31, 2018, and underwent retrievable inferior vena cava filter (RIVCF) placement in 103 centers in China. The primary endpoint of the study was RIVCF trapped embolus detected by inferior vena cava venography/ultrasound/computed tomography scanning or visible macroscopic thrombus before or during RIVCF retrieval. The relative factors of RIVCF trapped embolus were analyzed accordingly. RESULTS The average age of the patients was 61.0 (50.0-71.0) years. Retrievable inferior vena cava filter trapped embolus occurred in 308 patients (10.65%). The fracture location, surgery location, and endovascular intervention differed between RIVCF trapped embolus and non-RIVCF trapped embolus groups (p<0.001, respectively). By multivariate analysis, RIVCF trapped embolus were less common in older patients (odds ratio [OR]=0.998; p<0.001) and more common in patients with below-the-knee fracture (OR=1.093, p=0.038), thigh fracture (OR=1.118, p=0.007), and pelvis surgery (OR=1.067, p=0.016). In addition, compared with patients without endovascular intervention, patients with percutaneous mechanical thrombectomy (PMT) + catheter-directed thrombolysis (CDT) were more prone to develop RIVCF trapped embolus (OR=1.060, p=0.010). However, RIVCF trapped embolus was less common in patients with CDT (OR=0.961, p=0.004). CONCLUSIONS Lower limb fracture, pelvis surgery, and PMT + CDT are prone to cause trapped embolus. As a trapped embolus often represents the possibility of severe pulmonary embolism, lower limb fracture, pelvis surgery, and PMT + CDT could be risk factors of fatal pulmonary embolism. Due to the low incidence of trapped embolus, it is not necessary to place filters in elderly patients and CDT-only patients. CLINICAL IMPACT The purpose of this paper is to standardize the use of inferior vena cava filter and avoid unnecessary filter implantation through the summary and analysis of a large number of clinical data. At the same time, more attention should be paid to and active treatment should be given to high-risk groups of pulmonary embolism.
Collapse
Affiliation(s)
- Lei Zhang
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| | - Wen-Ping Hu
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
- Department of Vascular Surgery, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hao Zhang
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| | - Shi-Bo Xia
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| | - Hong-Fei Wang
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| | - Chao Song
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| | - Qing-Sheng Lu
- Department of Vascular Surgery, Changhai Hospital, Navy (Second) Military Medical University, Shanghai, China
| |
Collapse
|
3
|
Bajda J, Park AN, Raj A, Raj R, Gorantla VR. Inferior Vena Cava Filters and Complications: A Systematic Review. Cureus 2023; 15:e40038. [PMID: 37287823 PMCID: PMC10243179 DOI: 10.7759/cureus.40038] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2023] [Indexed: 06/09/2023] Open
Abstract
Inferior vena cava (IVC) filters have been used since the 1960s to treat patients with acute risk of pulmonary embolism (PE) to prevent migration of thrombus by trapping it within the filter. Traditional usage has been in patients with contraindication to anticoagulation that carry a significant mortality risk. In this systematic review, we sought to evaluate complications associated with placement of inferior vena cava filters based on published data from the past 20 years. A search was performed on October 6th, 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews, using three databases (ProQuest, PubMed and ScienceDirect) for articles published between the dates of February 1, 2002 and October 1, 2022. Results were filtered to include full-text, clinical studies, and randomized trials written in English pertaining to keywords "IVC filter AND complications", "Inferior Vena Cava Filter AND complications", "IVC filter AND thrombosis" and "Inferior Vena Cava Filter AND thrombosis". Articles identified by the three databases were pooled and further screened for relevance based on inclusion and exclusion criteria. Initial search results yielded 33,265 hits from all three databases combined. Screening criteria were applied, with 7721 results remaining. After further manual screening, including removal of duplicate hits, a total of 117 articles were selected for review. While there are no consensus guidelines for best practice, there is compelling evidence that IVC filters can provide significant protection against PE with minimal complications if the treatment window is appropriate. Increase in the variety of filter models has led to broader availability, but skepticism remains about their efficacy and safety, with ongoing controversy surrounding appropriate indications. Further research is needed to establish clear guidelines on appropriate indications for IVC placement and to determine time course of complications versus benefits for indwelling filters.
Collapse
Affiliation(s)
- Joe Bajda
- Anatomical Sciences, St. George's University School of Medicine, True Blue, GRD
| | - Ann N Park
- Medicine, St. George's University School of Medicine, True Blue, GRD
| | - Aishwarya Raj
- Vascular Surgery, St. George's University School of Medicine, True Blue, GRD
| | - Rhea Raj
- Anatomical Sciences, St. George's University School of Medicine, True Blue, GRD
| | | |
Collapse
|
4
|
Bistervels IM, Buchmüller A, Tardy B. Inferior vena cava filters in pregnancy: Safe or sorry? Front Cardiovasc Med 2022; 9:1026002. [DOI: 10.3389/fcvm.2022.1026002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
BackgroundPotential hazards of vena cava filters include migration, tilt, perforation, fracture, and in-filter thrombosis. Due to physiological changes during pregnancy, the incidence of these complications might be different in pregnant women.AimTo evaluate the use and safety of inferior vena cava filters in both women who had an inferior vena cava filter inserted during pregnancy, and in women who became pregnant with an inferior vena cava filter in situ.MethodsWe performed two searches in the literature using the keywords “vena cava filter”, “pregnancy” and “obstetrics”.ResultsThe literature search on women who had a filter inserted during pregnancy yielded 11 articles compiling data on 199 women. At least one filter complication was reported in 33/177 (19%) women and included in-filter thrombosis (n = 14), tilt (n = 6), migration (n = 5), perforation (n = 2), fracture (n = 3), misplacement (n = 1), air embolism (n = 1) and allergic reaction (n = 1). Two (1%) filter complications led to maternal deaths, of which at least one was directly associated with a filter insertion. Filter retrieval failed in 9/149 (6%) women. The search on women who became pregnant with a filter in situ resulted in data on 21 pregnancies in 14 women, of which one (6%) was complicated by uterine trauma, intraperitoneal hemorrhage and fetal death caused by perforation of the inferior vena cava filter.ConclusionThe risks of filter complications in pregnancy are comparable to the nonpregnant population, but could lead to fetal or maternal death. Therefore, only in limited situations such as extensive thrombosis with a contraindication for anticoagulants, inferior vena filters should be considered in pregnant women.
Collapse
|
5
|
Clements W, Marshall E, Lukies M, Joseph T, Tran H, Ban EJ, Koukounaras J. A retrospective cohort study assessing the incidence of inferior vena cava (IVC) occlusion following prophylactic IVC filter insertion: Is anticoagulation necessary during filter dwell? Injury 2022; 53:2763-2767. [PMID: 35773022 DOI: 10.1016/j.injury.2022.06.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/13/2022] [Accepted: 06/22/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Inferior vena cava (IVC) filters play a role in preventing venous thromboembolism after major trauma where deep venous thrombosis (DVT) risk is up to 80%. It has been suggested that IVC filters are thrombogenic and many patients are therefore placed on therapeutic anticoagulation during IVC filter dwell citing concern of in situ IVC thrombosis, even in the absence of existing DVT. METHODS Between 1 June 2018 and 31 December 2021, this retrospective study assessed the incidence of IVC thrombosis following prophylactic IVC filter insertion. Groups were defined according to the presence or absence of therapeutic anticoagulation during filter dwell. The primary outcome was the presence or absence of IVC thrombus at retrieval. RESULTS A total of 124 patients were included. Anticoagulation was prescribed in 29 and anticoagulation was not prescribed in 63. A further 32 patients developed a new thrombosis episode after the prophylactic IVC filter was placed, and 29 were prescribed anticoagulation part-way during filter dwell as a result of this diagnosis. No cases of IVC occlusion were observed in any patient group. CONCLUSIONS Caval thrombosis was not observed after prophylactic filter placement, with or without the prescription of anticoagulation. While prospective trials are needed to increase the level of evidence, based on these results the use of therapeutic anticoagulation during IVC filter dwell should not be dictated by the presence of an IVC filter alone but rather by the presence of a related thrombosis event.
Collapse
Affiliation(s)
- Warren Clements
- Department of Radiology, Alfred Health, Melbourne, Australia; Department of Surgery, Monash University, Australia; National Trauma Research Institute, Central Clinical School, Monash University, Melbourne, Australia.
| | - Elissa Marshall
- Department of Radiology, Alfred Health, Melbourne, Australia
| | - Matthew Lukies
- Department of Radiology, Alfred Health, Melbourne, Australia
| | - Tim Joseph
- Department of Radiology, Alfred Health, Melbourne, Australia
| | - Huyen Tran
- Australian Centre for Blood Diseases, Clinical Haematology Department, Monash University, Melbourne, Australia
| | - Ee Jun Ban
- National Trauma Research Institute, Central Clinical School, Monash University, Melbourne, Australia; Department of Trauma, Alfred Health, Melbourne, Australia
| | - Jim Koukounaras
- Department of Radiology, Alfred Health, Melbourne, Australia; Department of Surgery, Monash University, Australia
| |
Collapse
|
6
|
Zhang L, Li M, Zhu Y, Shi Z, Zhang W, Gao B, Li L, Fang Z, Yang G, Han W, Wang L, Yin L, Ke X, Yue J, Gu Z, Liu Z. Efficacy and safety of rivaroxaban in patients with inferior vena cava filter placement without anticoagulation contraindications (EPICT): a prospective randomised controlled trial study protocol. BMJ Open 2021; 11:e045530. [PMID: 34697109 PMCID: PMC8547359 DOI: 10.1136/bmjopen-2020-045530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Inferior vena cava (IVC) filters are commonly used in patients with venous thromboembolism to prevent fatal pulmonary embolism, but the thrombosis risk increases after filter placement. Warfarin is a widely anticoagulant, but long-term monitoring and dose adjustments are required. Anticoagulation with rivaroxaban is more straightforward as it dose not require laboratory monitoring. This study compares the efficacy and safety of rivaroxaban and warfarin as an in anticoagulation therapy for patients with IVC filter placement. METHODS AND ANALYSIS This is a multicentre, randomised controlled trial. In total, 200 patients with deep vein thrombosis (DVT) with IVC filter implantation from 10 hospitals will be recruited. The patients will be randomised to the experimental group (rivaroxaban) or the control group (nadroparin overlapped with warfarin). The primary outcomes include death of any cause, pulmonary embolism (PE)-related death, bleeding and recurrent PE/DVT. The secondary outcomes include the percentage of other vascular events, IVC filter retrieval failure and net clinical benefits. This study aims to provide reliable, verification for the efficacy and safety of rivaroxaban antithrombotic therapy after IVC filter placement. ETHICS AND DISSEMINATION The study was approved by the Human Research Ethics Committee of the Second Affiliated Hospital of Zhejiang University School of Medicine (approval number: (2019) 295). The results will be disseminated through presentations at scientific conferences and publications in peer-reviewed journals TRIAL REGISTRATION NUMBER: NCT04066764.
Collapse
Affiliation(s)
- Libin Zhang
- Vascular Surgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China
| | - Miaomiao Li
- Vascular Surgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China
| | - Yuefeng Zhu
- Vascular Surgery, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, Hangzhou, Zhejiang, China
| | - Zhenyu Shi
- Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Wan Zhang
- Vascular Surgery, Huadong Hospital Affiliated to Fudan University, Shanghai, China
| | - Bin Gao
- Vascular Surgery, Shanghai Fifth People's Hospital, Shanghai, China
| | - Lubin Li
- Vascular Surgery, Qindao University Medical College Affiliated Yantai Yuhuangding Hospital, Yantai, Shandong, China
| | - Zhengdong Fang
- Vascular Surgery, Anhui Provincial Hospital, Hefei, Anhui, China
| | - Guangwei Yang
- Vascular Surgery, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang, China
| | - Wei Han
- Vascualr Surgery, Zhejiang Xiaoshan Hospital, Hangzhou, Zhejiang, China
| | - Linjun Wang
- Vascular Surgery, Third Peoplles Hospital of Hangzhou, Hangzhou, Zhejiang, China
| | - Li Yin
- Vascular Surgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China
| | - Xueying Ke
- Vascular Surgery, Zhejiang University School of Medicine Sir Run Run Shaw Hospital, Hangzhou, Zhejiang, China
| | - Jianing Yue
- Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Zheng Gu
- Department of Clinical Medicine Engineering, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
| | - Zhenjie Liu
- Vascular Surgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China
| |
Collapse
|
7
|
Kobayashi T, Morishita E, Tsuda H, Neki R, Kojima T, Ohga S, Ochiai M, Adachi T, Miyata T. Clinical guidance for peripartum management of patients with hereditary thrombophilia. J Obstet Gynaecol Res 2021; 47:3008-3033. [PMID: 34169611 DOI: 10.1111/jog.14879] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/13/2021] [Accepted: 05/29/2021] [Indexed: 12/24/2022]
Abstract
Hereditary thrombophilia is a condition in which individuals are susceptible to the formation of thrombi due to a hereditary deficiency in anticoagulant factors, antithrombin (AT), protein C (PC), or protein S (PS). Many Japanese thrombophilia patients have PS deficiency, especially PS p.K196E (also called as PS Tokushima), which is exclusive to the Japanese population, and thrombosis sometimes occurs during pregnancy. At present, no management guidelines for pregnancy and delivery in thrombophilia patients have been developed. The Study Group for Hereditary Thrombophilia, one of the research groups of blood coagulation abnormalities in the Research Program on Rare and Intractable Diseases supported with the Research Grants of the Ministry of Health, Labour and Welfare Science, has therefore developed this clinical guidance to provide healthcare workers with necessary information on safe pregnancy, parturition and neonatal management, adopting a format of responses to seven clinical questions (CQ). At the end of each answer, the corresponding Recommendation Level (A, B, C) is indicated.
Collapse
Affiliation(s)
- Takao Kobayashi
- Department of Obstetrics and Gynecology, Hamamatsu Medical Center, Hamamatsu, Japan.,The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan
| | - Eriko Morishita
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Department of Laboratory Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Hiroko Tsuda
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Institute of Distribution Sciences, Nakamura Gakuen University, Fukuoka, Japan
| | - Reiko Neki
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Division of Counseling for Medical Genetics, Department of Obstetrics and Gynecology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Tetsuhito Kojima
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Medical Division, Aichi Health Promotion Foundation, Nagoya, Japan
| | - Shouichi Ohga
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masayuki Ochiai
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoko Adachi
- Department of Obstetrics and Gynecology, Aiiku Maternal and Child Health Center, Aiiku Hospital, Tokyo, Japan
| | - Toshiyuki Miyata
- The Study Group for Hereditary Thrombophilia, Research on Blood Coagulation Abnormalities, Research Program on Rare and Intractable Diseases, The Ministry of Health, Labour and Welfare Science Research Grants, Tokyo, Japan.,Department of Cerebrovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| |
Collapse
|
8
|
Jianping G, Razi M, Xu H, Ahmed M. Inferior vena cava filter thrombosis: An overview. INDIAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY 2020. [DOI: 10.4103/ijves.ijves_118_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
9
|
Geerts W, Selby R. Inferior vena cava filter use and patient safety: legacy or science? HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2017; 2017:686-692. [PMID: 29222322 PMCID: PMC6142573 DOI: 10.1182/asheducation-2017.1.686] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
There has been a dramatic increase in vena cava filter (VCF) use over the past 20 years in the absence of evidence that filters provide a net patient benefit or are required in most cases. This increase is largely attributable to the availability of retrievable filters and expanded indications, particularly as primary prophylaxis in patients thought to be at high risk of pulmonary embolism. Substantial variability in VCF use, unrelated to patient clinical factors, has been shown between hospitals, from region to region, and among various countries. Despite the lack of direct evidence for the benefit of VCFs for any indication, it is appropriate to insert a retrievable VCF in patients with a recent proximal deep vein thrombosis and an absolute contraindication to therapeutic anticoagulation and then to remove the filter once the bleeding risk decreases and the patient has been anticoagulated. Unfortunately, a high proportion of retrievable filters are not removed, even after the reason for their placement has long passed. Retrievable filters are associated with substantial rates of complications if they are not removed, including penetration of the vena caval wall, fracture and embolization of filter fragments, and caval occlusion. Patient safety priorities and medical-legal concerns mandate careful selection of patients for VCF placement and removal shortly after anticoagulation has been initiated.
Collapse
Affiliation(s)
- William Geerts
- Thromboembolism Program, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada; and
| | - Rita Selby
- Thromboembolism Program, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada; and
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|