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1.  Limitations of using synthetic blood clots for measuring in vitro clot capture efficiency of inferior vena cava filters 
The purpose of this study was first to evaluate the clot capture efficiency and capture location of six currently-marketed vena cava filters in a physiological venous flow loop, using synthetic polyacrylamide hydrogel clots, which were intended to simulate actual blood clots. After observing a measured anomaly for one of the test filters, we redirected the focus of the study to identify the cause of poor clot capture performance for large synthetic hydrogel clots. We hypothesized that the uncharacteristic low clot capture efficiency observed when testing the outlying filter can be attributed to the inadvertent use of dense, stiff synthetic hydrogel clots, and not as a result of the filter design or filter orientation. To study this issue, sheep blood clots and polyacrylamide (PA) synthetic clots were injected into a mock venous flow loop containing a clinical inferior vena cava (IVC) filter, and their captures were observed. Testing was performed with clots of various diameters (3.2, 4.8, and 6.4 mm), length-to-diameter ratios (1:1, 3:1, 10:1), and stiffness. By adjusting the chemical formulation, PA clots were fabricated to be soft, moderately stiff, or stiff with elastic moduli of 805 ± 2, 1696 ± 10 and 3295 ± 37 Pa, respectively. In comparison, the elastic moduli for freshly prepared sheep blood clots were 1690 ± 360 Pa. The outlying filter had a design that was characterized by peripheral gaps (up to 14 mm) between its wire struts. While a low clot capture rate was observed using large, stiff synthetic clots, the filter effectively captured similarly sized sheep blood clots and soft PA clots. Because the stiffer synthetic clots remained straight when approaching the filter in the IVC model flow loop, they were more likely to pass between the peripheral filter struts, while the softer, physiological clots tended to fold and were captured by the filter. These experiments demonstrated that if synthetic clots are used as a surrogate for animal or human blood clots for in vitro evaluation of vena cava filters, the material properties (eg, elastic modulus) and dynamic behavior of the surrogate should first be assessed to ensure that they accurately mimic an actual blood clot within the body.
PMCID: PMC3656916  PMID: 23690701
blood clot; elastic modulus; polyacrylamide hydrogel; in vitro testing of vena cava filters
2.  Vena Cava Filters in Spinal Cord Injuries: Evolving Technology 
Asymptomatic deep venous thrombosis (DVT) has been reported in 60% to 100% of persons with spinal cord injury (SCI). Several guidelines have been published detailing recommended venous thromboembolism (VTE) prophylaxis after acute SCI. Low-molecular-weight heparin, intermittent pneumatic compression (IPC) devices, and/or graduated compression stockings are recommended. Vena cava filters (VCFs) are recommended for secondary prophylaxis in certain situations.
To clarify the use of vena cava filters in patients with SCI.
Literature review.
Prophylactic use of vena cava filters has expanded in trauma patients, including individuals with SCI. Filter placement effectively prevents pulmonary emboli and has a low complication rate. Indications include pulmonary embolus while on anticoagulant therapy, presence of pulmonary embolus and contraindication for anticoagulation, and documented free-floating ileofemoral thrombus. VCFs should be considered in patients with complete motor paralysis caused by lesions in the high cervical cord (C2 and C3), with poor cardiopulmonary reserve, or with thrombus in the inferior vena cava despite anticoagulant prophylaxis. Three optional retrievable filters that are approved for use are discussed.
Retrievable VCFs are a safe, feasible option for secondary prophylaxis of VTE in patients with SCI. Objective criteria for temporary and permanent placement need to be defined.
PMCID: PMC1864806  PMID: 16859222
Spinal cord injuries; Deep vein thrombosis; Venous thromboembolism; Pulmonary embolism; Trauma; Thromboprophylaxis; Vena cava filters; Greenfield filters; Recovery; OptEase; TrapEase
3.  Chiari network: A case report and brief overview 
The Chiari network is mobile, net-like structures occasionally seen in right atrium near the opening of inferior vena cava and coronary sinus. This is usually of no clinical significance and is often diagnosed incidentally. However, sometimes it may cause diagnostic confusion with right atrial pathologies, and may favour thromboembolism by causing flow obstruction. It may be associated with infective endocarditis, arrhythmias, and migraine. Sometimes, it acts as a physical barrier during invasive procedures. The Chiari network has also been described to protect from pulmonary embolism by acting as an inferior vena cava filter due to its sieve-like effect at the cavo-atrial junction. Here, the Chiari network has been described in a case of Ebstein anomaly of tricuspid valve which produced diagnostic confusion during echocardiography. A brief overview has also been presented.
PMCID: PMC3809461  PMID: 24174864
Coronary sinus; Inferior vena cava; Ebstein anomaly
4.  Detection of atrial septal defect with left-to-right shunt by inferior vena cava contrast echocardiography. 
British Heart Journal  1982;47(5):445-453.
Contrast echocardiography was used before cardiac catheterisation in 37 patients with atrial septal defect and a left-to-right shunt and in 18 patients with a raised right atrial and ventricular pressure to assess the contrast echo effect in the inferior vena cava. Using two dimensional contrast apical echocardiography we found a negative contrast echo effect within the right atrium in many but not all patients with atrial defect. Contrast echoes entering the inferior vena cava during presystole or early to mid-diastole were detected in patients with heart disease causing raised right atrial and ventricular pressures and also in all patients with atrial septal defect. No contrast echo effect in the inferior vena cava was detected in 10 normal subjects. The sensitivity of this contrast pattern in the inferior vena cava in diagnosing atrial septal defect was 100%. When other conditions causing raised right atrial pressure were excluded, the specificity and predictive accuracy were 100% for both. The presystolic contrast echo effect in the inferior vena cava, semiquantitatively graded, correlated with the size of the shunt determined by oximetry. In 20 patients re-examined after the surgical correction of the atrial septal defect, no presystolic contrast echo effect was detected in the inferior vena cava. Contrast echocardiography of the inferior vena cava is a valuable and reliable method for diagnosing atrial septal defect with left-to-right shunt.
PMCID: PMC481161  PMID: 7073905
5.  Using inferior vena cava filters to prevent pulmonary embolism  
Canadian Family Physician  2008;54(1): 49 - 55 .
To review the evidence for using inferior vena cava (IVC) filters to prevent pulmonary embolism (PE) in high-risk patients.
Ovid MEDLINE was searched from 1966 to 2006 for all English-language papers on IVC filters. Evidence was graded according to the 3-level classification system. Most evidence found was level II.
Inferior vena cava filters are used to prevent PE in patients with contraindications to, complications of, or failure of anticoagulation therapy and patients with extensive free-floating thrombi or residual thrombi following massive PE. Current evidence indicates that IVC filters are largely effective; breakthrough PE occurs in only 0% to 6.2% of cases. Contraindications to implantation of IVC filters include lack of venous access, caval occlusion, uncorrectable coagulopathy, and sepsis. Complications include misplacement or embolization of the filter, vascular injury or thrombosis, pneumothorax, and air emboli. Recurrent PE, IVC thrombosis, filter migration, filter fracture, or penetration of the caval wall sometimes occur with long-term use.
When used appropriately, IVC filters are a safe and effective method of preventing PE. Using retrievable filters might reduce long-term complications.
PMCID: PMC2293317  PMID: 18208955
6.  Early occlusion control of the intrapericardial inferior vena cava under femoral–femoral extracorporeal circulation using a technique to prevent pulmonary embolism during nephrectomy for renal cell carcinoma with tumor thrombus: two case reports 
BMC Research Notes  2014;7:683.
Renal cell carcinoma with tumor thrombus extension into the inferior vena cava occurs in approximately 5% of cases. Despite such situations, an aggressive surgical approach is recommended. However, intraoperative prevention of pulmonary embolism by a fragmended tumor thrombus is necessary. To prevent pulmonary embolism, placement of a temporary suprarenal filter has been attempted, however, the precise placement of a temporary filter between the level of the hepatic vein and right atrium is not always easy because of its migration, tilting, and strut fracture. Here we report a method for early occlusion control of the intrapericardial inferior vena cava to prevent pulmonary embolism during nephrectomy in level II or III renal cell carcinoma tumor thrombus.
Case presentation
Our first case was a 37-year-old Japanese man with left renal cell carcinoma extending into the inferior vena cava below the main hepatic vein (level II) and our second was a 75-year-old Japanese man with right renal cell carcinoma extending into the retrohepatic inferior vena cava at the main hepatic vein (level III). En block resection of the kidney and the tumor thrombus was performed with the aid of partial extracorporeal circulation; the postoperative course of both patients was uneventful.
Control of intrapericardial inferior vena cava is a feasible method to prevent pulmonary embolism.
PMCID: PMC4190328  PMID: 25270542
Intrapericardial inferior vena cava; Renal cell carcinoma; Tumor thrombus; Pulmonary embolism
7.  An Economic Evaluation of Venous Thromboembolism Prophylaxis Strategies in Critically Ill Trauma Patients at Risk of Bleeding 
PLoS Medicine  2009;6(6):e1000098.
Using decision analysis, Henry Stelfox and colleagues estimate the cost-effectiveness of three venous thromboembolism prophylaxis strategies in patients with severe traumatic injuries who were also at risk for bleeding complications.
Critically ill trauma patients with severe injuries are at high risk for venous thromboembolism (VTE) and bleeding simultaneously. Currently, the optimal VTE prophylaxis strategy is unknown for trauma patients with a contraindication to pharmacological prophylaxis because of a risk of bleeding.
Methods and Findings
Using decision analysis, we estimated the cost effectiveness of three VTE prophylaxis strategies—pneumatic compression devices (PCDs) and expectant management alone, serial Doppler ultrasound (SDU) screening, and prophylactic insertion of a vena cava filter (VCF)—in trauma patients admitted to an intensive care unit (ICU) with severe injuries who were believed to have a contraindication to pharmacological prophylaxis for up to two weeks because of a risk of major bleeding. Data on the probability of deep vein thrombosis (DVT) and pulmonary embolism (PE), and on the effectiveness of the prophylactic strategies, were taken from observational and randomized controlled studies. The probabilities of in-hospital death, ICU and hospital discharge rates, and resource use were taken from a population-based cohort of trauma patients with severe injuries (injury severity scores >12) admitted to the ICU of a regional trauma centre. The incidence of DVT at 12 weeks was similar for the PCD (14.9%) and SDU (15.0%) strategies, but higher for the VCF (25.7%) strategy. Conversely, the incidence of PE at 12 weeks was highest in the PCD strategy (2.9%), followed by the SDU (1.5%) and VCF (0.3%) strategies. Expected mortality and quality-adjusted life years were nearly identical for all three management strategies. Expected health care costs at 12 weeks were Can$55,831 for the PCD strategy, Can$55,334 for the SDU screening strategy, and Can$57,377 for the VCF strategy, with similar trends noted over a lifetime analysis.
The attributable mortality due to PE in trauma patients with severe injuries is low relative to other causes of mortality. Prophylactic placement of VCF in patients at high risk of VTE who cannot receive pharmacological prophylaxis is expensive and associated with an increased risk of DVT. Compared to the other strategies, SDU screening was associated with better clinical outcomes and lower costs.
Please see later in the article for Editors' Summary
Editors' Summary
For patients who have been seriously injured in an accident or a violent attack (trauma patients), venous thromboembolism (VTE)—the formation of blood clots that limit the flow of blood through the veins—is a frequent and potentially fatal complication. The commonest form of VTE is deep vein thrombosis (DVT). “Distal” DVTs (clots that form in deep veins below the knee) affect about half of patients with severe trauma; “proximal” DVTs (clots that form above the knee) develop in one in five trauma patients. DVTs cause pain and swelling in the affected leg and can leave patients with a painful condition called post-thrombotic syndrome. Worse still, part of the clot can break off and travel to the lungs where it can cause a life-threatening pulmonary embolism (PE). Distal DVTs rarely embolize but, if untreated, half of patients who present with a proximal DVT will develop a PE, and 2%–3% of them will die as a result.
Why Was This Study Done?
VTE is usually prevented by using heparin, a drug that stops blood clotting, but clinicians treating critically ill trauma patients have a dilemma. Many of these patients are at high risk of serious bleeding complications so cannot be given heparin to prevent VTE. Nonpharmacological ways to prevent VTE include the use of pneumatic compression devices to keep the blood moving in the legs (clots often form in patients confined to bed because of the sluggish blood flow in their legs), repeated screening for blood clots using Doppler ultrasound, and the insertion of a “vena cava filter” into the vein that takes blood from the legs to the heart. This last device catches blood clots before they reach the lungs but increases the risk of DVT. Unfortunately, no-one knows which VTE prevention strategy works best in trauma patients who cannot be given heparin. In this study, therefore, the researchers use decision analysis (the systematic evaluation of the most important factors affecting a decision) to estimate the costs and likely clinical outcomes of these strategies.
What Did the Researchers Do and Find?
The researchers used cost and clinical data from patients admitted to a Canadian trauma center with severe head/neck and/or abdomen/pelvis injuries (patients with a high risk of bleeding complications likely to make heparin therapy dangerous for up to two weeks after the injury) to construct a Markov decision analysis model. They then fed published data on the chances of patients developing DVT or PE, and on the effectiveness of the three VTE prevention strategies, into the model to obtain estimates of the costs and clinical outcomes of the strategies at 12 weeks after the injury and over the patients' lifetime. The estimated incidence of DVT at 12 weeks was 15% for the pneumatic compression device and Doppler ultrasound strategies, but 25% for the vena cava filter strategy. By contrast, the estimated incidence of PE was 2.9% with the pneumatic compression device, 1.5% with Doppler ultrasound, but only 0.3% with the vena cava filter. The expected mortality with all three strategies was similar. Finally, the estimated health care costs per patient at 12 weeks were Can$55,334 and Can$55,831 for the Doppler ultrasound and pneumatic compression device strategies, respectively, but Can$57,377 for the vena cava filter strategy; similar trends were seen for lifetime health care costs.
What Do These Findings Mean?
As with all mathematical models, these findings depend on the data fed into the model and on the assumptions included in it. For example, because data from one Canadian trauma unit were used to construct the model, these findings may not be generalizable. Nevertheless, these findings suggest that, although VTE is common among patients with severe injuries, PE is not a major cause of death among these patients. They also suggest that the use of vena cava filters for VTE prevention in patients who cannot receive heparin should not be routinely used because it is expensive and increases the risk of DVT. Finally, these results suggest that, compared with the other strategies, serial Doppler ultrasound is associated with better clinical outcomes and lower costs.
Additional Information
Please access these Web sites via the online version of this summary at
The US National Heart Lung and Blood Institute provides information (including an animation) on deep vein thrombosis and pulmonary embolism
MedlinePlus provides links to more information about deep vein thrombosis and pulmonary embolism (in several languages)
The UK National Health Service Choices Web site has information on deep vein thrombosis and on embolism (in English and Spanish)
The Eastern Association for the Surgery of Trauma working group document Practice Management Guidelines for the Management of Venous Thromboembolism in Trauma Patients can be downloaded from the Internet
PMCID: PMC2695771  PMID: 19554085
8.  Inferior Vena Cava Filter Migration to the Right Ventricle Causing Nonsustained Ventricular Tachycardia 
Texas Heart Institute Journal  2013;40(3):316-319.
Inferior vena cava filters are commonly used to prevent pulmonary embolism in patients who manifest deep vein thrombosis and recurrent pulmonary embolism despite anticoagulation, or in patients with contraindications to anticoagulation. We report the case of a 69-year-old man with a structurally normal heart who experienced migration of an inferior vena cava filter to the right ventricle, which caused the abrupt onset of recurrent episodes of nonsustained ventricular tachycardia unresponsive to intravenous antiarrhythmic medication. Cardiac imaging revealed the location of the filter within the right ventricle, and the device was removed, with subsequent resolution of the arrhythmia. We anticipate that the incidence of inferior vena cava filter migration might increase in the future because of recent changes in device construction. The sudden appearance of nonsustained ventricular tachycardia in a patient with an inferior vena cava filter might indicate the occurrence of this potentially life-threatening sequela and should lead to emergent cardiac imaging.
PMCID: PMC3709234  PMID: 23914030
Foreign-body migration; inferior vena cava filter; pulmonary embolism/prevention & control; tachycardia, ventricular/etiology/diagnosis; vena cava, inferior; vena cava filters/adverse effects/utilization; venous thrombosis; ventricular tachycardia
9.  Fractured Inferior Vena Cava Filter Strut Presenting with ST-Segment Elevation and Cardiac Tamponade 
Texas Heart Institute Journal  2015;42(2):181-183.
The fracture of an inferior vena cava filter strut and its migration to the heart is a rare sequela of implanted inferior vena cava filters. Perforation through the right ventricle into the pericardium with resultant cardiopulmonary compromise is even less frequent. We report the case of a 53-year-old man who presented with chest pain and hypotension consequent to cardiac tamponade. A fractured inferior vena cava filter strut had migrated and perforated his right ventricle. The fractured strut was successfully removed by means of cardiac surgery. Inferior vena cava filters should be placed when necessary to minimize the risk of pulmonary embolism, and regular radiologic monitoring should be performed; however, the eventual extraction of retrievable filters should be considered. In addition to discussing the patient's case, we briefly review the relevant medical literature.
PMCID: PMC4382892  PMID: 25873837
Cardiac tamponade/etiology; device removal; equipment failure; foreign-body migration/complications/diagnosis/etiology/surgery; heart injuries/etiology; myocardial infarction/etiology; risk factors; treatment outcome; vena cava filters/adverse effects; vena cava, inferior/injuries
10.  IVC Filter Perforation through the Duodenum Found after Years of Abdominal Pain 
Patient: Female, 67
Final Diagnosis: IVC filter perforation through duodenum
Symptoms: Abdominal pain
Medication: —
Clinical Procedure: Esophagogastroduodenoscopy
Specialty: Gastroenterology and Hepatology
Challenging differential diagnosis
The number of IVC filter-related complications has increased with their growing utilization; however, IVC filter perforation of the duodenum is rare. It can manifest with nonspecific abdominal pain, gastrointestinal bleeding, cava-duodenal fistula, or small bowel obstruction.
Case Report:
A 67-year-old female presented with several years of right upper quadrant abdominal pain which was exacerbated by movement and food intake. She had a history of hepatic steatosis, cholecystectomy, and multiple DVTs with inferior vena cava filter placement. Physical exam was unremarkable. Laboratory tests demonstrated elevated alkaline phosphatase and transaminases. Esophagogastroduodenoscopy revealed a thin metallic foreign body embedded in the duodenal wall and protruding into the duodenal lumen with surrounding erythema and edema, but no active hemorrhage. Further evaluation with non-contrast CT scan revealed that one of the prongs of her IVC filter had perforated through the vena cava wall into the adjacent duodenum. Exploratory laparotomy was required for removal of the IVC filter and repair of the vena cava and duodenum. Her post-operative course was uneventful.
In patients with history of IVC filter placement with non-specific abdominal pain, a high clinical suspicion of IVC filter perforation of the duodenum should be raised, as diagnosis may be challenging. CT scan and EGD are valuable in the diagnosis. Excellent outcomes have been reported with open surgical filter removal. Low retrieval rates of IVC filters have led to increased complications; hence, early removal should be undertaken as clinically indicated.
PMCID: PMC4447199  PMID: 25979859
Duodenum; Endoscopy, Digestive System; Vena Cava Filters
11.  Image-Guided, Lobe-Specific Hydrodynamic Gene Delivery to Swine Liver 
Image-guided, lobe-specific hydrodynamic gene delivery to liver was assessed in pigs. The procedure involved image-guided insertion of a balloon catheter to the hepatic vein of the selected lobe from the jugular vein and hydrodynamic injection of plasmid DNA using a newly developed computer-controlled injection device. We demonstrated that the impact of the procedure was regional with minimal effects on neighboring lobes. Level of gene expression resulted from the procedure was 107 RLU/mg in the targeted lobes and 102−105 RLU/mg in the non-targeted lobes 4 hr after hydrodynamic injection of pCMV-Luc plasmids. Occlusion of blood flow in the inferior vena cava or inferior vena cava plus portal vein was effective in elevating hydrodynamic pressure in the targeted vasculature but did not enhance gene delivery efficiency. Physiological examination on pigs with inferior vena cava occlusion revealed transient decreases of blood pressure and respiration rate. Removal of occlusion from inferior vena cava resulted in a rapid and transient increase in heart rate. Occlusion of the portal vein and hepatic vein showed no effect on physiological and cardiac activities. No major changes in serum composition were observed. These results suggest that: (1) image-guided, lobe-specific hydrodynamic procedure is safe and effective for regional gene delivery to liver; (2) blockade in inferior vena cava should be avoided for hydrodynamic gene delivery to the liver; and (3) clinic application of hydrodynamic gene delivery to liver is feasible.
PMCID: PMC2680706  PMID: 19156134
Hydrodynamic gene delivery; gene therapy; gene delivery; nonviral vectors; hydrojector
12.  Malignant epithelioid angiomyolipoma invading the inferior vena cava: Using a temporary vena cava filter to prevent tumour emboli during nephrectomy 
Angiomyolipoma (AML) is generally considered to be benign and malignant angiomyolipoma is rare. This paper presents an extremely rare case of epithelioid AML with tumour thrombus invading inferior vena cava (IVC). We present the case of a 36-year-old woman with epithelioid AML with tumour thrombus invading inferior vena cava who underwent radical nephrectomy and IVC thrombectomy. As an adjunctive procedure, a temporary IVC filter was placed in suprarenal position before operation. One week after surgery, the temporary IVC filter was retrieved by femoral approach. Three months postoperatively, a computed tomography scan and abdominal ultrasonogaphy showed no evidence of thrombus in IVC or renal vein and no sign of tumour recurrence. Epithelioid AML is extremely rare and can be malignant, with invasion of the IVC or renal vein. Implanting temporary filter can prevent fatal pulmonary complication and avoid potential the side effects of permanent filter.
PMCID: PMC4137028  PMID: 25210566
13.  Retrieval of Gunther Tulip Vena Cava Filter with Thrombosed Hook and a Leg Incorporated into the Vena Cava Wall 
Annals of Vascular Diseases  2009;2(1):40-43.
A Gunther tulip vena cava filter was implanted in a patient with pulmonary embolism from deep venous thrombosis. The filter became unnecessary after therapy. However, retrieval by the standard method employing a vascular sheath placed via the transjugular approach in combination with a snare device was impossible. A thrombus occupying the apical hook made it difficult to snare the hook, also one filter leg was incorporated into the inferior vena cava wall. Therefore we modified an existing method to withdraw the filter. As the first step, the filter cone was snared using the snare-over-guide wire loop technique, and the cephalad site of the filter was introduced into the sheath. Then, a 12-French sheath was advanced from the femoral vein and, using a pusher, the distal legs of the filter were pushed, which resulted the filter leg that was incorporated into the inferior vena cava wall became detached. Finally the filter was successfully retrieved.
PMCID: PMC3595756  PMID: 23555355
embolism; pulmonary; interventional procedures; vena cava; filters
14.  Sonographic assessment of the inferior vena cava/aorta index measured with the transducer placed in the anterior median line and right anterior axillary line – a comparison 
Journal of Ultrasonography  2014;14(58):280-286.
The aim of the study was to compare the values of the sonographic inferior vena cava/ aorta index obtained with the transducer placed in the median line and right anterior axillary line.
Material and methods
The study enrolled 45 volunteers, including 33 women, aged 22.5 ± 1.26 with a negative history of circulatory and renal diseases. The study consisted in a sonographic assessment and measurement of the inferior vena cava and aorta by placing the transducer in the anterior median line and right anterior axillary line. The value of the inferior vena cava/aorta index was obtained by calculating the ratio of the diameters of the inferior vena cava and aorta. The diameter measurements were taken by placing the ultrasound transducer in the anterior median line and right anterior axillary line. Two examiners performed the measurement three times and used convex probes of 3.5–5 MHz. Additionally, the subjects’ weight, height and arterial blood pressure were taken.
Following a statistical analysis with the use of STATISTICA software, the following values of the inferior vena cava/aorta index were obtained: in the anterior median line – 1.43 ± 0.21, and in the right anterior axillary line – 1.285 ± 0.19. There was no statistically significant difference between the measurements obtained by the two examiners (p = 0.17). A strong correlation was noted between the inferior vena cava/ aorta indices calculated in both sites of transducer placement, which was irrespective of the examiners (the correlation coefficient: r = 0.61 and r = 0.71). The study indicate that the inferior vena cava/aorta index measured in the right anterior axillary line is a simple and reproducible method for determining the body fluid status; the examinations conducted in both sites may be used interchangeably. Further studies are needed to determine reference values for the inferior vena cava/aorta index measured in the right anterior axillary line.
PMCID: PMC4579682  PMID: 26674356
sonography; body fluid status; inferior vena cava; aorta; anterior axillary line
15.  Diagnosis and treatment of deep-vein thrombosis and approach to venous thromboembolism in obstetrics and gynecology 
Deep vein thrombosis (DVT) is a common condition in which the approach to its diagnosis has evolved over the years. Currently, an algorithm strategy combining pre-test probability, D-Dimer testing and compression ultrasound imaging allows for safe and convenient investigation of suspected lower-extremity thrombosis. Patients with low pre-test probability and a negative D-Dimer test result can have proximal DVT excluded without the need for diagnostic imaging. The mainstay of treatment of DVT is anticoagulation therapy, whereas interventions such as thrombolysis and placement of inferior vena cava filters are reserved for special situations. The use of low-molecular-weight heparin (LMW) allows for outpatient management of most patients with DVT. The duration of anticoagulation therapy depends on whether the primary event was idiopathic or secondary to a transient risk factor. More research is required to optimally define the factors that predict an increased risk of recurrent DVT to determine which patients can benefit from extended anticoagulant therapy. DVT is also a serious problem in the antenatal and postpartum period of pregnancy. Thromboembolic complications are the leading cause of both maternal and fetal morbidity and mortality. The incidence of venous thromboembolism during normal pregnancy is six-fold higher than in the general female population of childbearing age. The treatment of DVT during pregnancy deserves special mention, since oral anticoagulation therapy is generally avoided during pregnancy because of the teratogenic effects in the first trimester and the risk of fetal intracranial bleeding in the third trimester. LMW heparin is the treatment of choice for DVT during pregnancy. If acute DVT occurs near term, interrupting anticoagulation therapy may be hazardous because of the risk of pulmonary embolism. In this situation, placement of a retrievable inferior vena cava filter must be considered. However, there is no consensus as to what the appropriate dose should be and whether anti-Xa levels need to be monitored.
PMCID: PMC3939275  PMID: 24591986
Venous thrombosis; heparin; low- molecular- weight: heparin; anticoagulants; partial thromboplastin time; thromboembolism in pregnancy
16.  An Experimental Study to Determine the Role of Inferior Vena Cava Filter in Preventing Bone Cement Implantation Syndrome 
Iranian Journal of Radiology  2015;12(3):e14142.
Inferior vena cava filters (IVCF) are frequently used for preventing pulmonary embolism (PE) following deep venous thromboembolism.
The present study was designed to investigate whether IVCF could prevent or impede the occurrence of bone cement implantation syndrome (BCIS), since PE is considered as the central mechanism of BCIS.
Materials and Methods:
Fifteen sheep were divided into three groups: bone cement free (BCF) group, cement implantation (CI) group and IVCF group. In all the groups, an osteotomy proximal to the greater trochanter of left femur was carried out. In BCF group, the femoral canal was not reamed out or packed with any bone cement. In CI and IVCF groups, the left femoral canals were packed with bone cement, to simulate the cementing procedures carried out in hip replacement. An OptEase® filter was placed and released in inferior vena cava, prior to packing cement in the femoral canal in IVCF group, while the IVCF was not released in the CI group. The BCF group was considered as control.
Systolic blood pressure (SBP), saturation of oxygen (SaO2) and partial pressure of carbon dioxide (PaCO2) declined significantly 10 min after the bone cement packing, in CI group, compared to those in BCF group. This was accompanied by a rise in the arterial pH. However, IVCF prevented those changes in the CI group. On ultrasonography, there were dotted echoes in right atrium in the CI group, after bone cement packing, while such echoes were hardly seen in the IVCF group.
This study demonstrates that IVCF could prevent BCIS effectively, and, as a corollary, suggests that PE represents the leading cause of the constellation of BCIS symptoms.
PMCID: PMC4632131  PMID: 26557267
Bone Cement; Pulmonary Embolism; Vena Cava Filters; Arthroplasty, Replacement, Hip
17.  Protected Iliofemoral Venous Thrombectomy 
Texas Heart Institute Journal  2002;29(2):130-132.
Although thromboembolism is uncommon during pregnancy and the postpartum period, physicians should be alert to the possibility because the complications, such as pulmonary embolism, are often life threatening. Pregnant women who present with thromboembolic occlusion are particularly difficult to treat because thrombolysis is hazardous to the fetus and surgical intervention by any of several approaches is controversial.
A 22-year-old woman, in her 11th week of gestation, experienced an episode of pulmonary embolism and severe ischemic venous thrombosis of the left lower extremity. The cause was determined to be a severe protein S deficiency in combination with compression of the left iliac vein by the enlarged uterus.
The patient underwent emergency insertion of a retrievable vena cava filter and surgical iliofemoral venous thrombectomy with concomitant creation of a temporary femoral arteriovenous fistula. The inferior vena cava filter was inserted before the venous thrombectomy to prevent pulmonary embolism from clots dislodged during thrombectomy. When the filter was removed, medium-sized clots were found trapped in its coils, indicating the effectiveness of this approach. The operation resolved the severe ischemic venous thrombosis of the left leg, and the patency of the iliac vein was maintained throughout the pregnancy without embolic recurrence. At full term, the woman spontaneously delivered an 8-lb, 6-oz, healthy male infant. (Tex Heart Inst J 2002;29:130–2)
PMCID: PMC116741  PMID: 12075871
Femoral vein/surgery; heparin/therapeutic use; iliac vein/surgery; pregnancy complications, cardiovascular/surgery; pulmonary embolism/prevention & control; thrombectomy; thrombosis/therapy; vena cava filters; venous thrombosis/therapy
18.  Absence of inferior vena cava in 14-year old boy associated with deep venous thrombosis and positive Mycoplasma pneumoniae serum antibodies- a case report 
BMC Pediatrics  2015;15:40.
Absence of the inferior vena cava is a rare vascular anomaly, which usually remains asymptomatic in childhood. It is recognized as the risk factor for deep venous thrombosis, since the collateral circulation does not provide adequate drainage of the lower limbs. Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in school-aged children and adolescents. Mycoplasma pneumoniae infection might be associated with deep venous thrombosis but its pathophysiology remains unknown. According to previous reports, deep venous thrombosis due to Mycoplasma pneumoniae infection is associated with positive serum anticardiolipin antibodies. To our knowledge, we describe the first case of deep venous thrombosis associated with Mycoplasma pneumoniae serum antibodies indicating early stage of infection with negative anticardiolipin serum antibodies in adolescent with absence of inferior vena cava.
Case presentation
14-year old boy was admitted to the pediatric unit few days after the appendectomy complaining with pain of the left hip that caused him unable to walk. The pain was accompanied with subfebrile temperature. After clinical examination and additional tests, the boy was diagnosed with a deep venous thrombosis. Computed tomography revealed absence of the vena cava inferior distally to the hepatic veins and varices of the collateral circulation in the pelvis. Anticardiolipin IgM and IgG antibodies and antinuclear antibodies were not detected. Additionally, the Mycoplasma pneumoniae antibodies in classes IgM, IgA and IgG were detected in serum as another risk factor of thrombosis. After the initial treatment with low-molecular-weight heparin in combination with clarithromycin the clinical condition of the patient improved. The patient became a candidate for life-long anticoagulation therapy.
In this case Mycoplasma pneumoniae antibodies were associated with deep venous thrombosis in child with congenital absence of inferior vena cava. Uncommonly for deep venous thrombosis due to Mycoplasma pneumoniae infection, anticardiolipin antibodies were not detected in serum. It is important to remember in clinical practice that Mycoplasma pneumoniae affects coagulability and may trigger thrombosis, especially in the presence of other risk factors. The pathophysiology of this process remains unknown.
PMCID: PMC4399418  PMID: 25880637
Absence of inferior vena cava; Appendectomy; Deep venous thrombosis; Hypercoagulability; Low-molecular-weight heparin; Mycoplasma pneumoniae antibodies
19.  Inferior Vena Cava Filter Placement during Pregnancy: An Adjuvant Option When Medical Therapy Fails 
The authors present a case of a 27-year-old multiparous woman, with multiple thrombophilia, whose pregnancy was complicated with deep venous thrombosis requiring placement of a vena cava filter. At 15th week of gestation, following an acute deep venous thrombosis of the right inferior limb, anticoagulant therapy with low-molecular-weight heparin (LMWH) was instituted without improvement in her clinical status. Subsequently, at 18 weeks of pregnancy, LMWH was switched to warfarin. At 30th week of gestation, the maintenance of high thrombotic risk was the premise for placement of an inferior vena cava filter for prophylaxis of pulmonary embolism during childbirth and postpartum. There were no complications and a vaginal delivery was accomplished at 37 weeks of gestation. Venal placement of inferior vena cava filters is an attractive option as prophylaxis for pulmonary embolism during pregnancy.
PMCID: PMC3678500  PMID: 23781361
20.  A Population-Based Study of Inferior Vena Caval Filters in Patients Diagnosed With Acute Venous Thromboembolism 
Archives of internal medicine  2010;170(16):1456-1462.
To describe the frequency, indications, and outcomes following inferior vena cava (IVC) filter placement in a population-based sample of residents of the Worcester, MA, metropolitan area diagnosed with acute venous thromboembolism (VTE) in 1999, 2001, and 2003.
A retrospective chart review of inpatient and outpatient medical records was conducted. Recorded indication(s) for IVC filter placement was determined among a subset of cases from three Worcester tertiary care hospitals. Three thrombosis specialists assessed the appropriateness of IVC filter placement.
Among 1547 greater Worcester residents with validated acute VTE and without a prior IVC filter, 203 (13.1%) had an IVC filter placed after acute VTE. Patients with an IVC filter placed were older, had more co-morbidities, and had higher mortality during 3-year follow-up. There was unanimous agreement by panel members that use of an IVC filter was appropriate in 51% of cases, and inappropriate in 26% of cases, with no consensus in the remaining 23%.
In this community-based study, IVC filters were frequently utilized in the management of patients with acute VTE. Placement was deemed to be appropriate in approximately half of the patients, but was not appropriate or debatable in the remaining cases. Given increasing use of IVC filters, prospective studies are clearly needed to better define the indications for, and efficacy of, IVC filter placement.
PMCID: PMC3691870  PMID: 20837832
21.  The inferior vena cava (IVC) syndrome as the initial manifestation of newly diagnosed gastric adenocarcinoma: a case report 
Vena cava compression is a relatively rare initial manifestation of underlying malignancy. The superior vena cava syndrome, which is characterized by facial plethora, jugular venous distension, and arm swelling, is a well-known entity associated with bronchogenic carcinoma. Less common is the compression of the inferior vena cava. To the best of my knowledge, this is the first reported case of newly diagnosed gastric adenocarcinoma presenting initially as the inferior vena cava syndrome. The unique aspect about this case is that it highlights a rare presentation before diagnosis of gastric adenocarcinoma.
Case presentation
A 56-year-old Malaysian woman with a past medical history of iron deficiency anemia presented with lower extremity edema and progressive fatigue of 1 month’s duration. She had significant worsening of leg swelling after standing for short periods of time. She also reported epigastric discomfort, which led to an additional workup, including computed tomography of the abdomen and pelvis. This revealed a 3cm×2.9cm mass in the stomach, extensive hepatic metastasis, and severe inferior vena cava compression. The patient was examined further with esophagogastroduodenoscopy, and a biopsy showed gastric adenocarcinoma.
This report describes a case of a patient with inferior vena cava syndrome as a unique presentation of previously undiagnosed stage IV gastric adenocarcinoma. Patients presenting with inferior vena cava syndrome should undergo prompt evaluation for underlying malignancies that have a predilection for hepatic metastasis. This case is important because earlier recognition of this syndrome can lead to earlier workup and thus detection of malignancy. Prompt initiation of treatment, including chemotherapy or vena cava stent placement, can result in improved patient outcome.
PMCID: PMC4584485  PMID: 26411979
Gastric adenocarcinoma; Hepatic metastasis; Inferior vena cava; Paraneoplastic syndrome; Secondary prevention; Superior vena cava
22.  The ripped cava. 
Lacerations of the inferior vena cava are associated with a high mortality and may be difficult to repair. The majority of injuries are due to penetrating trauma. Rapid transportation to definitive surgical care with effective resuscitation may improve mortality. Surgical management includes adequate treatment of hypovolemic shock due to blood loss. Placement of intravenous infusion sites below the level of the diaphragm may be effective. Operative control of the inferior vena cava can be accomplished by directed digital compression followed by a proximal and distal control. Injuries of the inferior vena cava above the level of the renal veins are associated with an increased mortality. Retrohepatic and subdiaphragmatic injuries are highly lethal. This article discusses appropriate surgical approaches for repair of the inferior vena cava above and below the diaphragm.
PMCID: PMC2607809  PMID: 7752285
23.  Increasing abdominal pressure with and without PEEP: effects on intra-peritoneal, intra-organ and intra-vascular pressures 
BMC Gastroenterology  2010;10:70.
Intra-organ and intra-vascular pressures can be used to estimate intra-abdominal pressure. The aim of this prospective, interventional study was to assess the effect of PEEP on the accuracy of pressure estimation at different measurement sites in a model of increased abdominal pressure.
Catheters for pressure measurement were inserted into the stomach, urinary bladder, peritoneal cavity, pulmonary artery and inferior vena cava of 12 pigs. The pressures were recorded simultaneously at baseline, during 10 cm H20 PEEP, external abdominal pressure (7 kg weight) plus PEEP, external abdominal pressure without PEEP, and again under baseline conditions.
Results (mean ± SD)
PEEP alone increased diastolic pulmonary artery and inferior vena cava pressure but had no effect on the other pressures. PEEP and external abdominal pressure increased intraperitoneal pressure from 6 ± 1 mm Hg to 9 ± 2 mm Hg, urinary bladder pressure from 6 ± 2 mm Hg to 11 ± 2 mm Hg (p = 0.012), intragastric pressure from 6 ± 2 mm Hg to 11 ± 2 mm Hg (all p ≤ 0.001), and inferior vena cava pressure from 11 ± 4 mm Hg to 15 ± 4 mm Hg (p = 0.01). Removing PEEP and maintaining extraabdominal pressure was associated with a decrease in pulmonary artery diastolic but not in any of the other pressures. There was a significant correlation among all pressures. Bias (-1 mm Hg) and limits of agreement (3 to -5 mm Hg) were similar for the comparisons of absolute intraperitoneal pressure with intra-gastric and urinary bladder pressure, but larger for the comparison between intraperitoneal and inferior vena cava pressure (-5, 0 to -11 mm Hg). Bias (0 to -1 mm Hg) and limits of agreement (3 to -4 mm Hg) for pressure changes were similar for all comparisons
Our data suggest that pressure changes induced by external abdominal pressure were not modified by changing PEEP between 0 and 10 cm H20.
PMCID: PMC2912801  PMID: 20598159
24.  Venous outflow obstruction and portopulmonary hypertension after orthotopic liver transplantation 
Patient: Female, 54
Final Diagnosis: Suprahepatic inferior vena cava anastomosis stricture
Symptoms: Ascites • fatigue • lower limb edema • hepatomegaly
Medication: —
Clinical Procedure: —
Specialty: Transplantology • Critical Care Medicine
Unusual clinical course
Suprahepatic inferior vena cava anastomosis stricture is an unusual vascular complication after orthotopic liver transplantation with the “piggyback” technique. Clinical manifestations are dependent upon the severity of the stenosis. Portopulmonary hypertension after orthotopic liver transplantation is a complication that carries high mortality due to cardiopulmonary dysfunction. The pathogenesis of pulmonary vascular disorders after orthotopic liver transplantation remains uncertain.
Case Report:
We report a case of acute right heart pressure overload after surgical correction of the suprahepatic inferior vena cava anastomotic stricture in a 54-year-old woman who had preexisting pulmonary arterial hypertension associated with portal hypertension after orthotopic liver transplantation. Twenty months posttransplantation, she developed fatigue and progressive ascites. On admission, the patient had hepatomegaly, ascites, and lower limb edema. Symptoms in the patient developed gradually over time.
Recurrent portal hypertension by vascular complications is a cause of pulmonary arterial hypertension after orthotopic liver transplantation. Clinical manifestations of suprahepatic inferior vena cava anastomotic stenosis are dependent upon their severity. Sildenafil is an effective drug for treatment of pulmonary arterial hyper-tension after portal hypertension by vascular complications.
PMCID: PMC3775614  PMID: 24046802
liver transplantation; suprahepatic inferior vena cava; portopulmonary hypertension; pulmonary arterial hypertension; acute cor pulmonale
25.  Cross-sectional echocardiographic diagnosis of systemic venous return. 
British Heart Journal  1982;48(4):388-403.
To determine the sensitivity and specificity of cross-sectional echocardiography in diagnosing anomalous systemic venous return we used the technique in 800 consecutive children with congenital heart disease and whom the diagnosis was ultimately confirmed by angiography. Cross-sectional echocardiography was performed without prior knowledge of the diagnosis in all but 11 patients, who were recalled because of a known abnormality of atrial situs. The sensitivity of cross-sectional echocardiographic detection of various structures was as follows: right superior vena cava 792/792 (100%); left superior vena cava 46/48 (96%); bilateral superior vena cava 38/40 (95%); bridging innominate vein with bilateral superior vena cava 13/18 (72%); connection of superior caval segment to heart (coronary sinus or either atrium) (100%); absence of suprarenal inferior vena cava 23/23 (100%); azygos continuation of the inferior vena cava 31/33 (91%); downstream connection of azygos continuation, once seen, 21/21 (100%); partial anomalous hepatic venous connection (one hepatic vein not connected to the inferior vena cava) 1/1 (100%); total anomalous hepatic venous connection (invariably associated with left isomerism) 23/23 (100%). The specificity of each above diagnoses was 100% except in one infant with exomphalos in whom absence of the suprarenal inferior vena cava was incorrectly diagnosed. Thus cross-sectional echocardiography is an extremely specific and highly sensitive method of recognizing anomalous systemic venous return. It is therefore of great value of planning both cardiac catheterisation and cannulation for open heart surgery.
PMCID: PMC481265  PMID: 6751361

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