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1.  Vena Cava Filters in Spinal Cord Injuries: Evolving Technology 
Background:
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.
Objective:
To clarify the use of vena cava filters in patients with SCI.
Methods:
Literature review.
Results:
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.
Conclusion:
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
2.  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.
doi:10.2147/MDER.S42555
PMCID: PMC3656916  PMID: 23690701
blood clot; elastic modulus; polyacrylamide hydrogel; in vitro testing of vena cava filters
3.  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.
Images
PMCID: PMC481161  PMID: 7073905
4.  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.
doi:10.1016/j.jsha.2012.12.002
PMCID: PMC3809461  PMID: 24174864
Coronary sinus; Inferior vena cava; Ebstein anomaly
5.  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(1):683.
Background
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.
Conclusion
Control of intrapericardial inferior vena cava is a feasible method to prevent pulmonary embolism.
doi:10.1186/1756-0500-7-683
PMCID: PMC4190328  PMID: 25270542
Intrapericardial inferior vena cava; Renal cell carcinoma; Tumor thrombus; Pulmonary embolism
6.  Using inferior vena cava filters to prevent pulmonary embolism  
Canadian Family Physician  2008;54(1): 49 - 55 .
OBJECTIVE
To review the evidence for using inferior vena cava (IVC) filters to prevent pulmonary embolism (PE) in high-risk patients.
QUALITY OF EVIDENCE
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.
MAIN MESSAGE
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.
CONCLUSION
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
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.
Background
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.
Conclusions
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
Background
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 http://dx.doi.org/10.1371/journal.pmed.1000098.
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
doi:10.1371/journal.pmed.1000098
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.  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.
doi:10.1038/mt.2008.294
PMCID: PMC2680706  PMID: 19156134
Hydrodynamic gene delivery; gene therapy; gene delivery; nonviral vectors; hydrojector
10.  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.
doi:10.5489/cuaj.1814
PMCID: PMC4137028  PMID: 25210566
11.  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.
doi:10.3400/avd.AVDht08008
PMCID: PMC3595756  PMID: 23555355
embolism; pulmonary; interventional procedures; vena cava; filters
12.  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.
doi:10.5152/jtgga.2011.39
PMCID: PMC3939275  PMID: 24591986
Venous thrombosis; heparin; low- molecular- weight: heparin; anticoagulants; partial thromboplastin time; thromboembolism in pregnancy
13.  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
14.  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.
doi:10.1155/2013/821635
PMCID: PMC3678500  PMID: 23781361
15.  Increasing abdominal pressure with and without PEEP: effects on intra-peritoneal, intra-organ and intra-vascular pressures 
BMC Gastroenterology  2010;10:70.
Background
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.
Methods
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
Conclusions
Our data suggest that pressure changes induced by external abdominal pressure were not modified by changing PEEP between 0 and 10 cm H20.
doi:10.1186/1471-230X-10-70
PMCID: PMC2912801  PMID: 20598159
16.  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
17.  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
Objective:
Unusual clinical course
Background:
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.
Conclusions:
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.
doi:10.12659/AJCR.889261
PMCID: PMC3775614  PMID: 24046802
liver transplantation; suprahepatic inferior vena cava; portopulmonary hypertension; pulmonary arterial hypertension; acute cor pulmonale
18.  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.
Objectives
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.
Methods
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.
Results
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%.
Conclusions
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.
doi:10.1001/archinternmed.2010.272
PMCID: PMC3691870  PMID: 20837832
19.  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.
Images
PMCID: PMC481265  PMID: 6751361
20.  Two dimensional echocardiographic diagnosis of situs. 
British Heart Journal  1982;48(2):97-108.
At present there is no reliable method of recognising atrial isomerism by two dimensional echocardiography. We therefore used two dimensional echocardiography to examine 158 patients including 25 with atrial isomerism and four with situs inversus. Particular attention was paid to the short and long axis subcostal scans of the abdomen. Using the position of the inferior vena cava and the aorta with respect to the spine it was possible to separate those with situs solitus from the others. Two false positives for abnormal situs had exomphalos. In situs solitus the aorta lay to the left of the spine and the inferior vena cava lay to the right. One patient with situs solitus and azygos continuation of the inferior vena cava also had inferior vena cava to right atrial connection. In the four patients with situs inversus the mirror image of the normal pattern was present. In nine patients with right isomerism the inferior vena cava and aorta ran together on one or other side of the spine. The inferior vena cava, anterior to the aorta at the level of the diaphragm, received at least the right hepatic veins (normal or partial anomalous hepatic venous connection). Of the 16 patients with left isomerism, 14 had azygos continuation of the inferior vena cava which was visualised posterior to the aorta in all but two. All patients with left isomerism had total anomalous hepatic venous connection to one or both atria via one or two separate veins. Two dimensional echocardiography therefore provides the means of detecting abnormal atrial situs and of diagnosing right or left isomerism in the great majority of patients, if not all.
Images
PMCID: PMC481212  PMID: 7093090
21.  Inferior Vena Cava Filters for Recurrent Thrombosis 
Texas Heart Institute Journal  2007;34(2):187-194.
Inferior vena cava filters are often used as alternatives to anticoagulant therapy for the prevention of pulmonary embolism. Many of the clinical data that support the use of these devices stem from relatively limited retrospective studies.
The dual purpose of this review is to examine the incidence of thrombotic complications associated with inferior vena cava filters and to discuss the role of anticoagulant therapy concurrent with filter placement. Device-associated morbidity and overall efficacy can be considered only in the context of rates of vena cava thrombosis, insertion-site thrombosis, recurrent deep venous thrombosis, and recurrent pulmonary embolism.
PMCID: PMC1894721  PMID: 17622366
Anticoagulants/contraindications/therapeutic use; combined modality therapy; device removal; equipment design/safety/trends; evaluation studies; patient selection; prosthesis implantation; pulmonary embolism/prevention & control/therapy; recurrence; risk factors; thrombolytic therapy/methods; treatment outcome; vena cava filters/adverse effects/classification/contraindications/history/statistics & numerical data/trends/utilization; venous thrombosis/complications/prevention & control/therapy
22.  Duodenal perforation by an inferior vena cava filter in a polyarteritis nodosa sufferer 
Highlights
•Inferior vena cava filters are used in the management of venous thromboembolism.•Duodenal perforation is a rare but potentially life-threatening complication.•The pros and cons of IVC filter insertion must be considered in steroid dependent patients with concurrent vasculopathy.
INTRODUCTION
Inferior vena cava (IVC) filters are currently used in the management of pulmonary embolism (PE) and lower limb venous thromboembolism (VTE). Despite their widespread use, associated complications including duodenal perforation have been reported.
PRESENTATION OF CASE
We describe a unique case of duodenal perforation 2 years post IVC filter insertion in a patient with polyarteritis nodosa (steroid dependent) and thrombocytopenia secondary to chronic cyclophosphamide use.
DISCUSSION
IVC filters are commonly employed in the management of VTE. Associated complications have been reported including filter migration, fracture and adjacent organ perforation. There is growing consensus that temporary IVC filters should be retrieved as soon as possible with dedicated IVC filter registries to ensure patients are not lost to follow-up post insertion.
CONCLUSION
Duodenal perforation is a rare complication of IVC filter insertion. This case however illustrates the potentially catastrophic consequences of a relatively common endovascular procedure. Caution should be taken when considering the insertion of IVC filters in patients with longstanding vasculopathies who are on immunosuppressants.
doi:10.1016/j.ijscr.2014.11.030
PMCID: PMC4275850  PMID: 25437665
Duodenum; IVC filter; Perforation; Polyarteritis nodosa
23.  Flow during exercise in the total cavopulmonary connection measured by magnetic resonance velocity mapping 
Heart  2002;87(6):554-558.
Objective: To measure caval and pulmonary flows at rest and immediately after exercise in patients with total cavopulmonary connection (TCPC).
Design: An observational study using the patients as their own controls.
Setting: Using a combination of magnetic resonance (MR) phase contrast techniques and an MR compatible bicycle ergometer, blood flow was measured in the superior vena cava, the tunnel from the inferior vena cava, and in the left and right pulmonary arteries during rest and on exercise (0.5 W/kg and 1.0 W/kg).
Patients: Eleven patients aged 11.4 (4.6) years (mean (SD)) were studied 6.3 (3.8) years after TCPC operation.
Main outcome measures: Volume flow measured in all four branches of the TCPC connection during rest and exercise.
Results: Systemic venous return (inferior vena cava plus superior vena cava) increased from 2.5 (0.1) l/min/m2 (mean (SEM)) to 4.4 (0.4) l/min/m2 (p < 0.05) during exercise, with even distribution to the two pulmonary arteries. At rest, inferior vena caval flow was higher than superior vena caval flow, at 1.4 (0.1) v 1.1 (0.1) l/min/m2 (p < 0.05). During exercise, inferior vena caval flow doubled (to 3.0 (0.3) l/min/m2) while superior vena caval flow only increased slightly (to 1.4 (0.1) l/min/m2) (p < 0.05). The increased blood flow mainly reflected an increase in heart rate. The inferior vena caval to superior vena caval flow ratio was 1.4 (0.1) at rest and increased to 1.8 (0.1) (p < 0.05) at 0.5 W/kg, and to 2.2 (0.2) at 1.0 W/kg (p < 0.05).
Conclusions: Quantitative flow measurements can be performed immediately after exercise using MR techniques. Supine leg exercise resulted in a more than twofold increase in inferior vena caval flow. This was equally distributed to the two lungs, indicating that pulmonary resistance rather than geometry decides flow distribution in the TCPC circulation.
PMCID: PMC1767137  PMID: 12010939
flow; Fontan circulation; exercise; magnetic resonance imaging
24.  The Mid-Term Efficacy and Safety of a Permanent Nitinol IVC Filter (TrapEase) 
Korean Journal of Radiology  2005;6(2):110-116.
Objective
1) To evaluate the mid-term efficacy and safety of a permanent nitinol inferior vena cava (IVC) filter; 2) to evaluate filter effectiveness, filter stability and caval occlusion.
Materials and Methods
A prospective evaluation of the TrapEase IVC filter was performed on 42 patients (eight men, 34 women) ranging in age from 22 to 78 years (mean age 66 years). All patients were ill with a high risk of pulmonary embolism (PE). Indications for filter placement were: 1) deep vein thrombosis with recurrent thromboembolism; 2) and/or free-floating thrombus with contraindication to anticoagulation; and 3) complications in achieving adequate anticoagulation. Follow-up evaluations (mean: 15.4 months, range: 2 to 28 months) were performed at 6- and 12-month intervals after the procedure and included clinical histories, chart reviews, plain film, Doppler ultrasounds, and contrasted abdominal CT scans.
Results
In follow-up evaluations, the data analysis revealed no cases of symptomatic PE. There were no cases of filter migration, insertion site thrombosis, filter fracture, or vessel wall perforation. During the study, there was one case of filter thrombosis; early symptomatic thrombosis that was successfully treated in the hospital. Of the 42 subjects, eight died. These deaths were not related to the filter device or the implantation procedure, but to the underlying disease.
Conclusion
This study demonstrates that the TrapEase permanent IVC filter is a safe and an effective device with low complication rates and is best used in patients with thromboembolic disease with a high risk of PE.
doi:10.3348/kjr.2005.6.2.110
PMCID: PMC2686418  PMID: 15968150
Pulmonary thromboembolism; IVC Filter; IVC thrombosis
25.  Development of a spontaneously beating vein by cardiomyocyte transplantation in the wall of the inferior vena cava in a rat: A pilot study 
Purpose
The puopose of this study was to determine whether it is feasible to develop a vein that rhythmically beats by implanting immature cardiomyocytes in its wall.
Methods and Results
Neonatal cardiomyocytes (n=6, 5×106 cells each) or medium (n=6) only were transplanted into the wall of the inferior vena cava in female Fisher rats. At 3 weeks after transplantation, the grafted site of the inferior vena cava was exposed and videotaped. The vena cava was processed for histology. Distinct rhythmic beating of the vena cava at the site of cell injection (at a rate lower than aortic beating) was observed in 6 of 6 rats treated with neonatal cardiomyocyte injections, but 0 of 6 animals receiving media. The vena cava continued to beat spontaneously and rhythmically after the aortas were clamped and after the heart was excised. The beating was manifest by visual contraction and relaxation of the vessel wall. The spontaneous beating rate was 101 ± 7 beats per minute at 1~3 minutes after excision of the heart. Hematoxylin and eosin staining showed viable grafts in the wall of the vena cava in 6/6 vena cava implanted with neonatal cardiac cells; but in 0/6 vena cava receiving medium. Neonatal cardiomyocytes in the graft matured with cross striations and stained positive for the muscle marker sacromeric actin.
Conclusions
The present study demonstrates that neonatal cardiomyocytes survive, mature, and spontaneously and rhythmically contract when implanted in the wall of a vein.
doi:10.1016/j.jvs.2006.12.013
PMCID: PMC1983370  PMID: 17398391

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