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.
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.
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.
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.
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.
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
Deep venous thrombosis prophylaxis is essential to the appropriate management of multisystem trauma patients. Without thromboprophylaxis, the rate of venous thrombosis and subsequent pulmonary embolism is substantial. Three prophylactic modalities are common: pharmacologic anticoagulation, mechanical compression devices, and inferior vena cava filtration. A systematic review was completed using PRISMA guidelines to evaluate the potential complications of DVT prophylactic options. Level one evidence currently supports the use of low molecular weight heparins for thromboprophylaxis in the trauma patient. Unfortunately, multiple techniques are not infrequently required for complex multisystem trauma patients. Each modality has potential complications. The risks of heparin include bleeding and heparin induced thrombocytopenia. Mechanical compression devices can result in local soft tissue injury, bleeding and patient non-compliance. Inferior vena cava filters migrate, cause inferior vena cava occlusion, and penetrate the vessel wall. While the use of these techniques can be life saving, they must be appropriately utilized.
The Tempofilter II is a widely used temporary vena cava filter. Its unique design, which includes a long tethering catheter with a subcutaneous anchor, facilitates the deployment and retrieval of the device. Despite this, the Tempofilter II has been used only in the inferior vena cava of patients with lower extremity deep venous thrombosis. In this article, we present a case of superior vena cava filtering using the Tempofilter II in patients with upper extremity deep venous thrombosis.
Embolism, pulmonary; Veins, extremities; Veins, thrombosis; Vena cavae, filter; Vena cavae, interventional procedure
A 14-year-old patient presented with bilateral pneumonia and pleural effusions, septic arthritis of the hip, deep venous thrombosis, and pulmonary thromboembolism. Methicillin-sensitive Staphylococcus aureus (S. aureus) containing the Panton Valentine Leukocidin (PVL) genes was isolated. Contraindication to anticoagulation prompted inferior vena cava filter placement. He completed 4 weeks of treatment with flucloxacillin, with good clinical outcome.
S. aureus containing PVL genes should be sought in cases of necrotizing pneumonia as it seems to increase the risk of severe multifocal infection and thrombotic complications.
There are few reports of placement of filters during S. aureus sepsis and bacteraemia. This case highlights that when anticoagulation is not feasible, an inferior vena cava filter can be inserted safely, even in patients with active sepsis and high risk for seeding of the filter. Long-term follow-up confirmed a successful outcome with sterilization of the septic thrombosis with no further pulmonary embolism or additional sepsis episodes.
Therapeutic and prophylactic inferior vena cava (IVC) filters should be placed based on currently accepted indications to prevent a fatal pulmonary embolism (PE). The protective effect of filters is offset by the potential for lower extremity deep venous thrombosis (DVT), caval thrombosis, and possible otherwise unnecessary life-long anticoagulation (AC). The duration of treatment for most DVTs or PEs is 3 to 6 months of AC/filter. Filters should be retrieved when duration of treatment for a DVT/PE has been met, the risk of a PE is no longer high, and/or there is no longer a contraindication to AC. An effective system that leads to improving the retrieval rate of filters must include education of the patient, a tracking system to minimize patient lost to follow-up, and dedicated personnel to oversee the process. If these goals are accomplished, interventionalists can help decrease the incidence of a fatal PE during the high-risk period, and also decrease the risk of a DVT or the use of otherwise unnecessary life-long AC in subsequent years. Currently, there is much room for improvement in the frequency that IVCF patients are systematically followed and filters are retrieved. The principles discussed in this report will be helpful in this process.
Retrievable inferior vena cava filters; tracking inferior vena cava filter patients; improving retrieval of inferior vena cava filters
Characteristics and outcomes of patients undergoing inferior vena cava (IVC) filter insertion are not well reported. Particularly, the role of long term anticoagulation in these patients is unclear.
(1) To describe in a cohort of patients undergoing IVC filter insertion, underlying diseases, indications for filter insertion, complications, and survival. (2) To determine the effect of long term anticoagulant treatment on thromboembolism and patient survival.
A retrospective analysis of 109 consecutive patients undergoing IVC filter insertion in two university hospitals.
Average age was 67.4 years. Median duration of follow up was two years. Indications for IVC filter insertion were: contraindication to anticoagulation (n = 61, 56%), prophylactic insertion (n = 29, 27%), thromboembolism while receiving adequate anticoagulation (n = 17, 15%), and non‐compliance with anticoagulation (n = 2, 2%). Insertion related complications were groin haematoma in four patients (3.5%) and localised infection at the puncture site in one patient (0.9%). Fifty six patients (51.4%) died during the study period. Of these, 22 received long term anticoagulants and 34 did not. Overall and thrombosis free survival was greater in the anticoagulant treated group (median survival not reached) than in the untreated group (median survival = 12 months). Patients not receiving long term anticoagulation after IVC filter insertion were nearly 2.5‐fold more likely to die or experience venous thromboembolism.
IVC filter insertion was a safe procedure and was performed for appropriate indications in the patients studied. In patients surviving for longer than 30 days, prolonged administration of oral anticoagulants was associated with improved survival with no significant increase in haemorrhagic complications.
vena cava filter; anticoagulation
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.
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.
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.
Pulmonary thromboembolism; IVC Filter; IVC thrombosis
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.
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.
Spinal cord injuries; Deep vein thrombosis; Venous thromboembolism; Pulmonary embolism; Trauma; Thromboprophylaxis; Vena cava filters; Greenfield filters; Recovery; OptEase; TrapEase
Inferior vena cava filters have been used frequently for decades to prevent pulmonary embolism in medical, surgical and trauma patients. With the advent of temporary or retrievable filters, the use of these filters has increased substantially. However, the enhanced design and attributes that make these devices attractive for short-term benefit and retrieval are not without risk. Two cases of symptomatic inferior vena cava wall penetration are reported – one of which required surgical intervention.
Inferior vena cava filter; Inferior vena cava filter complications; Inferior vena cava wall penetration; Retrievable filter
Inferior vena cava (IVC) filter thrombosis is a complex problem. Thrombus within an IVC filter may range from an asymptomatic small thrombus to critical IVC occlusion that affects both lower extremities. The published experience of IVC thrombosis management in relation to filters is either anecdotal or limited to a small group of patients; however, endovascular treatment methods appear to be safe and effective in patients with IVC thrombosis. This review focuses on filter-related IVC thrombosis and its endovascular management.
vena cava filters; vena cava inferior; venous thrombosis/therapy; thrombectomy/methods
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.
The purpose of this study was to examine the incidence of new or recurrent venous thromboembolism (VTE) after retrieval of inferior vena cava (IVC) filters and risk factors associated with such recurrence. Between March 2001 and September 2008, at our institution, implanted retrievable vena cava filters were retrieved in 76 patients. The incidence of new or recurrent VTE after retrieval was reviewed and numerous variables were analyzed to assess risk factors for redevelopment of VTE after filter retrieval. In 5 (6.6%) of the 76 patients, redevelopment or worsening of VTE was seen after retrieval of the filter. Three patients (4.0%) had recurrent deep venous thrombosis (DVT) in the lower extremities and 2 (2.6%) had development of pulmonary embolism, resulting in death. Although there was no significant difference in the incidence of new or recurrent VTE related to any risk factor investigated, a tendency for development of VTE after filter retrieval was higher in patients in whom DVT in the lower extremities had been so severe during filter implantation that interventional radiological therapies in addition to traditional anticoagulation therapies were required (40% in patients with recurrent VTE vs. 23% in those without VTE; p = 0.5866 according to Fisher’s exact probability test) and in patients in whom DVT remained at the time of filter retrieval (60% in patients with recurrent VTE vs. 37% in those without VTE; p = 0.3637). In conclusion, new or recurrent VTE was rare after retrieval of IVC filters but was most likely to occur in patients who had severe DVT during filter implantation and/or in patients with a DVT that remained at the time of filter retrieval. We must point out that the fatality rate from PE after filter removal was high (2.6%).
Pulmonary embolism; Thrombosis of extremities; Interventional procedures; Vena cava filters
Objectives: To describe the mode of presentation, interventions, and outcome of HIV infected patients with pulmonary embolism and a contraindication to anticoagulation, who were treated with a bird's nest filter.
Methods: Retrospective review of case records and imaging department database at UCL Hospitals, London, UK.
Results: Three patients had pulmonary embolism and contraindications to anticoagulation. Contraindications were concomitant intracerebral pathology in two patients (one also had bleeding from gastric Kaposi's sarcoma and the other was cognitively impaired with HIV associated dementia complex) and alcohol induced liver disease/binge drinking in the third patient. Anticoagulation was avoided by introducing a bird's nest filter into the inferior vena cava via the common femoral vein. During follow up (7, 8, and 21 months) no complications or recurrent pulmonary emboli occurred.
Conclusion: The bird's nest inferior vena cava filter has a role in preventing further pulmonary emboli in HIV infected patients with contraindications to anticoagulation.
Key Words: pulmonary embolism; HIV; AIDS; haemorrhage; anticoagulation
To examine the specific effect of extracellular fluid (ECF) volume expansion on phosphate excretion studies were performed in thyroparathyroidectomized dogs receiving saline solution intravenously. The natriuresis resulting from ECF volume expansion was consistently accompanied by an increase in phosphate excretion. The possible role of increased filtered load of phosphate was eliminated in experiments in which the filtered load of phosphate was reduced by acute reduction in the glomerular filtration rate. Despite considerable reductions in filtered phosphate, ECF volume expansion resulted in a consistent increase in phosphate excretion. Furthermore, the possible contribution of alteration in blood composition was investigated in experiments in which saline was infused during thoracic inferior vena cava constriction. In these experiments saline infusion failed to increase sodium or phosphate excretion. Cessation of saline infusion and release of caval constriction resulted in a prompt natriuresis and increased phosphate excretion. It is concluded from these studies that extracellular fluid volume expansion results in an increased phosphate excretion in the parathyroidectomized dog. This effect is the specific consequence of ECF volume expansion and is not due to increase in the filtered load of phosphate or alterations in blood composition.
The inferior vena cava (IVC) filter is known as an effective and safe method for preventing fatal pulmonary thromboembolism in patients with deep vein thrombosis. Usually, the remaining IVC filters are asymptomatic and do not cause clinical problems. We report a case of duodenal perforation caused by a remaining IVC filter.
Venous disease; Complication; Foreign bodies; Penetrating trauma; Vena cava filters
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.
Hydrodynamic gene delivery; gene therapy; gene delivery; nonviral vectors; hydrojector
Dislocation and migration of the inferior vena cava filter to the right heart is an uncommon but serious complication, requiring prompt diagnosis and appropriate therapy. We report the case of a seventy-year old man, who had previously undergone vena cava filter implantation and who was admitted to the Intensive Care Unit due to acute respiratory distress with the suspect of pneumonia-related sepsis. Due to the worsening of hemodynamics and the development of cardiogenic shock, the patient underwent bedside echocardiography, which on the contrary revealed dislocation of the filter and the entrapment of the device within the tricuspid valve and chordae tendineae. This evidence was confirmed also by the chest-abdominal X-ray. The patient underwent tricuspid valve surgical replacement and successfully recovered. The transthoracic and transesophageal echocardiographies performed in the intensive care unit were able to first orient the diagnostic efforts toward the correct cause.
vena cava filter; cardiogenic shock; echocardiography; intensive care unit
Heparin-induced thrombocytopenia type II (HIT II) is a rare immune-mediated complication of heparin. The diagnosis of HIT is considered in patients exposed to heparin, presenting with thrombocytopenia and thrombosis.
We present two cases with massive pulmonary embolism and HIT, successfully treated with the administration of fondaparinux, an alternative anticoagulant, combined with the insertion of an inferior vena cava filter for the prevention of new thromboembolic events. The two cases supplement the available data of the use of fondaparinux in patients with HIT and pulmonary embolism, before further large studies establish its efficacy and safety in this group of patients. Moreover, the management of these patients reveals the need for future evaluation of the combined therapy of alternative anticoagulant agents with the placement of vena cava filters.
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)
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
The objective of this study was to assess the clinical safety and efficacy of vena cava filter (VCF) placement, with particular emphasis on the incidence and risk factors of inferior vena cava thrombosis (VCT) after VCF placement.
Clinical data of patients with venous thromboembolism (VTE), with or without placement of VCF, were analyzed in a retrospective single-center audit of medical records from January 2005 to June 2009. The collected data included demographics, procedural details, filter type, indications, and complications.
A total of 168 cases of VTE (82 with VCF; 86 without VCF) were examined. Over a median follow-up of 24.2 months, VCT occurred in 18 of 82 patients with VCFs (11 males, 7 females, mean age 55.4 years). In 86 patients without VCFs, VCT occurred in only 6 individuals (4 males, 2 females) during the study period. VCT was observed more frequently in patients fitted with VCFs than in those without VCFs (22% vs. 7.0%).
The incidence of VCT in patients with VTE after VCF implantation was 22% approximately. Anticoagulation therapy should be continued for all patients with VCF placement, unless there is a specific contraindication. Almost all instances of VCT in patients with VCF implants in our study occurred after stopping anticoagulation treatment. The use of VCFs is increasing, and more trials are needed to confirm their benefit and accurately assess their safety.
vena cava filters; venous thromboembolism; complication
Use of inferior vena cava (IVC) filters has been increasing over time. However, because of the increased risk of deep vein thrombosis with permanent filters, placement of retrievable filters has been recommended. Little is known about the factors associated with planned retrieval of IVC filters.
To describe rates and predictors of plans to retrieve IVC filters in hospitalized patients.
We identified all IVC filter placements from 2001–2006 at an academic medical center and reviewed medical charts to obtain data about patient characteristics, filter retrieval plans, and retrieval success rates. Multivariable logistic regression was used to identify independent predictors of planned filter retrieval in patients with retrievable filters.
Out of 240 patients who underwent placement of retrievable IVC filters, only 73 (30.4%) had documented plans for filter retrieval. Factors associated with lower rates of planned filter retrieval included a history of cancer [adjusted odds ratio (OR) and 95% confidence interval 0.2 (0.1–0.5)] and not being discharged on anticoagulants [OR 0.1 (0.1–0.3)]. In addition, 36 (21.6%) of patients without retrieval plans had no contraindications to retrieval. Of the 62 patients who underwent attempted filter retrieval, 25.8% of filters could not be successfully removed.
Only 30.4% of patients who underwent placement of a retrievable IVC filter had documented plans for filter removal. Although most patients had justifiable reasons for filter retention, 21.6% of patients had no clear contraindications to filter removal. Efforts to improve rates of filter retrieval in appropriate patients may help reduce the long-term complications of IVC filters.
inferior vena cava; filter retrieval; deep vein thrombosis
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.
The present study demonstrates that neonatal cardiomyocytes survive, mature, and spontaneously and rhythmically contract when implanted in the wall of a vein.