Percutaneous transabdominal embolization of thoracic duct lacerations in animals

Changes of thoracic duct flow and morphology in an animal model of elevated central venous pressure

Objective: Investigation of lymph fluid dynamics in thoracic duct during central venous pressure elevation.

Background: Lymphatic flow is affected by elevated central venous pressure (CVP) in congestive heart failure. The changes of thoracic duct (TD) lymph flow have not been studied chronically in the setting of elevated CVP. This study is to investigate fluid dynamics and remodeling of the TD in the elevated CVP animal model.

Methods: A flow probe was implanted on the swine TD (n = 6) and tricuspid regurgitation (TR) was created by cutting tricuspid chordae percutaneously. Six swine were used as control group animals. The TD flow was measured for 2 weeks (baseline) before TR and 4 weeks postop-TR surgery. Arterial pressure and CVP were measured. The pressure and flow in the TD were measured percutaneously. Histological and morphological analyses were performed.

Results: TR resulted in an increase in CVP from 4.2 ± 2.6 to 10.1 ± 4.3 mmHg (p < 0.05). The lymph flow in the TD increased from 0.78 ± 1.06 before TR to 8.8 ± 4.8 ml/min (p < 0.05) 2 days post-TR and remained plateau for 4 weeks, i.e., the TD flow remained approximately 8–11 fold its baseline. Compared to the 8.1 ± 3.2 mmHg control group, the TD average pressures at the lymphovenous junction increased to 14.6 ± 5.7 mmHg in the TR group (p < 0.05). The TD diameter and wall thickness increased from 3.35 ± 0.37 mm and 0.06 ± 0.01 mm in control to 4.32 ± 0.57 mm and 0.26 ± 0.02 mm (p < 0.05) in the TR group, respectively.

Conclusion: The elevated CVP results in a significant increase in TD flow and pressure which causes the TD’s outward remodeling and thickening. Our study implicates that the outward remodeling may result in the TD valve incompetence due to failure coaptation of leaflets.

Role of Interventional Radiology in the Management of Non-aortic Thoracic Trauma

Trauma remains a leading cause of death for all age groups, and nearly two-thirds of these individuals suffer thoracic trauma. Due to the various types of injuries, including vascular and nonvascular, interventional radiology plays a major role in the acute and chronic management of the thoracic trauma patient. Interventional radiologists are critical members in the multidisciplinary team focusing on treatment of the patient with thoracic injury. Through case presentations, this article will review the role of interventional radiology in the management of trauma patients suffering thoracic injuries.

Percutaneous Radiofrequency Ablation to Occlude the Thoracic Duct: Preclinical Studies in Swine for a Potential Alternative to Embolization

PURPOSE

To investigate the feasibility of percutaneous radiofrequency ablation (RFA) to occlude the thoracic duct (TD) in a swine model with imaging and histologic correlation.

MATERIALS AND METHODS

Six swine underwent TD RFA. Two terminal (4 hours; 1 open, 1 percutaneous) and four survival (30 days; all percutaneous) studies were performed. Two 20-gauge needles were placed adjacent to the TD under direct visualization after right thoracotomy or under fluoroscopic guidance using a percutaneous transabdominal approach after intranodal lymphangiography. Radiofrequency electrodes were advanced through the needles and ablation was performed at 90 degrees Celsius for 90 seconds. Lymphangiography was performed and the TD and adjacent structures were resected and examined microscopically at the end of each study period.

RESULTS

Four of six subjects survived the planned study period and underwent follow up lymphangiography. Two subjects in the survival group were euthanized early; 1 after developing an acute chylothorax and 1 due to gastric volvulus 14 days after ablation. Occlusion of the targeted TD segment was noted on lymphangiography in 3 of 4 remaining subjects (2 acute, 1 survival). Histology 4 hours after RFA demonstrated necrosis of the TD wall and hemorrhage within the lumen. Histology at 14 and 30 days revealed fibrosis with hemosiderin laden macrophages replacing the ablated TD. Collagen degeneration within the aortic wall involving a maximum of 60% thickness was noted in 5/6 subjects.

CONCLUSION

Percutaneous RFA can achieve short-segment TD occlusion. Further study is needed to improve safety and demonstrate clinical efficacy in treating TD leaks.

Embolization of the thoracic duct in patients with iatrogenic chylothorax

Chylothorax is leakage of lymphatic fluid accumulating in the pleural cavity due to the thoracic duct's (TD) trauma or obstructions. It generally occurs as a traumatic complication after general thoracic surgery procedures (0.4%), especially after esophagectomy (4.7-8.6%). Traditionally, surgical intervention is performed if conservative management fails, but reports of high mortality (2.1%) and morbidity (38%) have led to the development of a minimally invasive percutaneous treatment method; TD embolization (TDE). The records of all patients treated for chylothorax with TDE from April 2015 to June 2019 were reviewed. Only patients with iatrogenic chylothorax were included. The outcomes measures are defined as a technical and a clinical success. A technical success, is defined as the ability to perform the embolization procedure, thereby injecting embolizing material Histoacryl with or without coils. A clinical success is defined as a complete cessation of lymphatic leakage into the pleural cavity without surgical intervention and, therefore, a cured patient. Lymphography was performed in all patients, and visualization of cisterna chyli was achieved in 14/17 patients (82.4%). Of the 17 patients included, 15 patients were successfully embolized and cured of chylothorax (88.2%). Successfully embolized patients had a median discharge time of 7 days. Most patients reported postprocedural pain, which was dealt with using conventional pain medication. TDE seems like a safe percutaneous treatment technique with a high clinical success rate in iatrogenic chylothorax patients which can be readily implemented if the clinical experience is available..

Research Priorities in Lymphatic Interventions: Recommendations from a Multidisciplinary Research Consensus Panel

Recognizing the increasing importance of lymphatic interventions, the Society of Interventional Radiology Foundation brought together a multidisciplinary group of key opinion leaders in lymphatic medicine to define the priorities in lymphatic research. On February 21, 2020, SIRF convened a multidisciplinary Research Consensus Panel (RCP) of experts in the lymphatic field. During the meeting, the panel and audience discussed potential future research priorities. The panelists ranked the discussed research priorities based on clinical relevance, overall impact, and technical feasibility. The following research topics were prioritized by RCP: lymphatic decompression in patients with congestive heart failure, detoxification of thoracic duct lymph in acute illness, development of newer agents for lymphatic imaging, characterization of organ-based lymph composition, and development of lymphatic interventions to treat ascites in liver cirrhosis. The RCP priorities underscored that the lymphatic system plays an important role not only in the intrinsic lymphatic diseases but in conditions that traditionally are not considered to be lymphatic such as congestive heart failure, liver cirrhosis, and critical illness. The advancement of the research in these areas will lead the field of lymphatic interventions to the next level.

Traumatic Chylothorax: Approach and Outcomes

Traumatic chylothorax occurs more often now than in historic reports. In part, this is due to the increased ability to perform more advanced and aggressive thoracic resections and cardiovascular surgeries as well as the improved mortality of cancer patients. If untreated, chylothorax can result in significant morbidity and mortality, particularly in patients with underlying malignancy. Thoracic duct embolization for chylothorax was the first successful lymphatic intervention and has been performed for over 20 years. An overview of the clinical and technical approach to thoracic duct embolization for traumatic chylothorax is presented in addition to a review of outcomes.

Interventional Therapies for Thoracic Duct Injury and Intractable Chylothorax

Injury to the thoracic duct with resultant chylothorax can cause significant patient morbidity and mortality. Conservative treatment strategies often fail to address the problem. Open surgical and percutaneous approaches are often required to manage patients with refractory chylothorax. This review describes in detail the major role of minimally invasive interventional therapies for thoracic duct (TD) injury. The review emphasizes strategies for identifying the TD on preprocedural imaging and describes various techniques for percutaneous access to the TD. The advantages and disadvantages of several approaches for accessing the duct are discussed. The technique of duct embolization is highlighted. The role of the minimally invasive percutaneous approach over open surgical approaches is discussed with a review of clinical outcomes, as reported in the literature. This review will also briefly discuss the surgical approach to TD ligation.

Lymphangiography and Post-lymphangiographic Multidetector CT for Preclinical Lymphatic Interventions in a Rabbit Model

PURPOSE

To describe the feasibility of lymphangiography and the visibility of the lymphatic system using post-lymphangiographic multidetector CT (MDCT) for preclinical lymphatic interventions in a rabbit model.

MATERIALS AND METHODS

Lymphangiography via the popliteal lymph node or vessel after surgical exposure was performed, using six healthy female Japanese White rabbits. Lipiodol was manually injected for lymphangiography. Post-lymphangiographic MDCT examinations were performed in all rabbits. The dataset images were subjected to image processing analysis utilizing the three-dimensional maximum intensity projection technique. Three reviewers evaluated the degree of depiction of the lymphatic system using a four-point visual score (1, poor; 2, fair; 3, good; 4, excellent). The distance between the body surface and cisterna chyli was measured on post-lymphangiographic MDCT axial image.

RESULTS

Lymphangiography was successfully performed in all rabbits. The popliteal lymph node was detectable in 90%. The visualization of lymphatic system via the popliteal node was achieved in 89%. Mean visual scores of > 3.0 were realized by the right femoral lymphatic vessel, left femoral lymphatic vessel, left iliac lymphatic vessel, left lumbar lymphatic trunks and cisterna chyli, whereas mean visual scores of < 3.0 were yielded by the right iliac lymphatic vessel, right lumbar lymphatic trunks and thoracic duct. The distance between the body surface and cisterna chyli on post-lymphangiographic MDCT axial images was 4.33 ± 0.14 cm.

CONCLUSION

Lymphangiography is feasible, and the visibility of the lymphatic system on post-lymphangiographic MDCT in a rabbit model provides enough information for interventional radiologists to perform preclinical lymphatic interventions.

Lymphangiography and thoracic duct embolization following unsuccessful thoracic duct ligation: Imaging findings and outcomes

OBJECTIVE

To summarize the imaging findings and outcomes of thoracic duct (TD) embolization (TDE) performed in patients with chylous leaks persisting after TD ligation (TDL).

MATERIALS AND METHODS

In this review of 50 patients (30 males and 20 females; median age, 54 years) referred for TDE following unsuccessful surgical TDL, records were reviewed for lymphangiographic findings, technical success of TDE, and outcome of TDE. Comparisons between groups were performed using the Fisher exact test.

RESULTS

The causes of chylothorax were traumatic in 39 patients (78%) and nontraumatic in 11 (22%). Lymphangiography identified missed TDL in 30 patients (60%) and complete TDL in 15 patients (30%); however, in 12 of these 15 patients, collaterals around the ligation site supplying the leak could be identified. Incomplete ligation was observed in 4 patients (8%). In 1 patient (2%), a second TD was identified circumventing a complete ligation of the main TD. TDE was performed in 49 patients, and TD disruption was performed in 1 patient. Resolution of the chylous leak occurred in 45 patients (90%). There were 3 minor complications that resulted in no clinical sequela.

CONCLUSIONS

TDE produced cessation of chylous leak in the majority of the patients with persistent chylothorax after surgical TDL. Missed ligation is the most common finding on lymphangiography in patients with failed TDL. These findings support the use of image-guided closure of TD leaks.

MRI of the Central Lymphatic System: Indications, Imaging Technique, and Pre-Procedural Planning

Magnetic resonance imaging is increasingly being used to evaluate the lymphatic system. Advances in magnetic resonance (MR) software and hardware allow improved visualization of lymph nodes and lymphatic vessels. We describe how MR lymphangiography can be used to diagnose central lymphatic system anatomy and pathology, which can be used for diagnostic purposes or for pre-procedural planning.

Usefulness of CBCT and guidance software for percutaneous embolization of a lymphatic leakage after thyroidectomy for cancer

Lymphatic leakage can develop as an iatrogenic complication of thoracic, cardiac, and neck surgery. The management of this complication may be challenging and involves more specialists. Percutaneous, image-guided techniques may offer two advantages: mini-invasivity and ability to image and identify the anatomy and the site of the leakage. We report a case of refractory cervical chylous leakage after thyroidectomy and lymphadenectomy for cancer that was successfully treated with an ultrasound-guided intranodal lymphangiography and a percutaneous puncture of the leak performed using CBCT as imaging guidance.

Thoracic duct embolization for chylous leaks

Chylous leaks, such as chylothorax and chylopericardium, are uncommon effusions resulting from the leakage of intestinal lymphatic fluid from the thoracic duct (TD) and its tributaries, or intestinal lymphatic ducts. The cause can be either traumatic (thoracic surgery) or nontraumatic (idiopathic, malignancy). Treatment has traditionally consisted of dietary modification (nonfat diet) and/or surgery (TD ligation, pleurodesis). Thoracic duct embolization (TDE) has become a viable treatment alternative due to it high success rate and minimal complications. In this article, the authors describe the etiologies of chylothorax, patient population, outcomes, and long-term follow-up of TDE patients. Relevant lymphatic anatomy and physiology are reviewed, with special attention paid to the formation of the duct by tributaries at the cisterna chyli (CC). The technique of TDE is outlined, including bilateral pedal lymphangiography, TD cannulation, and embolic agents used for the procedure.

Management of chylothorax via percutaneous embolization

PURPOSE OF REVIEW

The purpose of this review is to present a novel radiologic percutaneous transabdominal technique for treating high-output chylothorax by thoracic duct embolization, and to demonstrate that it can be potentially safer than the traditional treatment by surgical open-chest thoracic duct ligation.

RECENT FINDINGS

Pedal lymphography is initially performed to opacify large retroperitoneal lymph channels; a suitable duct more than 2 mm in diameter is then punctured transabdominally to allow catheterization and embolization of the thoracic duct under fluoroscopic guidance. If feeding lymphatic channels are too small for catheterization, they can often be occluded by needle disruption. This percutaneous interventional technique, which has been used in 60 patients with mostly high-output chylothorax caused by thoracic surgery, resulted in a 65% cure rate with no morbidity. Back-up surgical thoracic duct ligation was performed promptly on suitable lower risk patients when the percutaneous procedure failed.

SUMMARY

We have found that two thirds of patients presenting with life-threatening chylothorax can be safely treated by percutaneous transabdominal thoracic duct blockage. When successful, this novel interventional procedure can obviate repeat major thoracic surgery and shorten hospital stays.

Management of unremitting chylothorax by percutaneous embolization and blockage of retroperitoneal lymphatic vessels in 42 patients

PURPOSE

To demonstrate the applicability, technique, and efficacy of percutaneous transabdominal catheter embolization or needle disruption of retroperitoneal lymphatic vessels in the treatment of high-output or unremitting chylothorax.

MATERIALS AND METHODS

Forty-two patients (21 men, 21 women; mean age, 56 y; range, 19-80 y) who had chylothorax with various etiologies were referred from the thoracic surgery department for treatment as soon as chylothorax was documented. The thoracic duct was punctured and catheterized via a peritoneal cannula to facilitate embolization with use of microcoils, particles, or glue; if there were no lymph trunks that could be catheterized, attempts were made to disrupt lymph collaterals with use of needles.

RESULTS

The thoracic duct was catheterized in 29 patients and embolized in 26 patients. In patients with lymph trunks that could be catheterized, treatment resulted in cure within 7 days in 16 patients and partial response with cure within 3 weeks in six patients. In the patients with lymph trunks that could not be catheterized (n = 16), disruption with use of needles resulted in cure in five patients and partial response in two patients. Cure and partial response rates after thoracic duct embolization and needle disruption were 73.8%, with no morbidity. Surgical thoracic duct ligation was performed in seven patients. The nonprocedural mortality rate was 19%. Follow-up was 3 months or longer.

CONCLUSIONS

Effective percutaneous treatment of high-output or medically uncontrollable chylothorax was performed promptly and safely in more than 70% of referred cases. This procedure should be attempted, especially if patients are very ill, before riskier surgical thoracic duct ligation is considered.

Invasive radiology for pediatric trauma

Interventional radiology has assumed an expanded role in the management of the pediatric trauma patient. Transcatheter endovascular embolization for the polytraumatized and bleeding patient has proven to be effective and potentially life saving. Nonvascular interventional techniques can be applied to the pediatric trauma patient with curative or temporizing effects. The minimally invasive nature and rapidity of these procedures allows their emergent use in both the unstable and stable pediatric trauma patient.

Management of chylothorax by percutaneous catheterization and embolization of the thoracic duct: prospective trial

PURPOSE

To prospectively assess the efficacy of percutaneous transabdominal thoracic duct catheterization and embolization in the management of patients with high-output chylothoracic effusions.

MATERIALS AND METHODS

Eleven consecutive patients (four women and seven men; mean age, 53 years) were referred with chylothorax secondary to esophagectomy (n = 4), lobectomy (n = 1), lung transplant (n = 1), coronary artery bypass (n = 1), aortic graft (n = 2), lymphangioleiomyomatosis (n = 1), and gunshot wound (n = 1). Two patients were brought by ambulance and referred back to their hospital on the same day. Pedal lymphography was used to opacify the cisterna chyli or major retroperitoneal lymphatic trunks. When patent, these were punctured under local anesthesia with a fine needle and the thoracic duct was catheterized over a microguide wire with use of a 3-F catheter; the duct was embolized with platinum coils. Patients were followed up for decrease in thoracic drainage output and morbidity.

RESULTS

There were no retroperitoneal ducts suitable for catheterization in six patients because of previous abdominal surgery, trauma, or lymphangioleiomyomatosis; the thoracic duct was successfully catheterized in five patients, a 45% technical success rate. Thoracic duct embolization was performed in four patients, with cure of effusion in two. In the other two patients, one with lymphangioleiomyomatosis and the other with nonchylous pleural fluid, continued effusion was successfully treated by means of pleurodesis. Of two patients with previous thoracic duct ligation, one was found to have the duct incompletely tied. The authors were surprised to find that previous major abdominal surgery, chronic aortic dissection, and lymphangioleiomyomatosis could obliterate major retroperitoneal lymphatic ducts and the cisterna chyli. Percutaneous study of the thoracic duct with aqueous contrast medium was more sensitive than lymphography with iodinated oil. There was no morbidity.

CONCLUSIONS

Catheterization of the thoracic duct was possible in all patients who had patent major retroperitoneal lymphatic trunks. Thoracic duct embolization was curative in patients with demonstrable duct leakage. Previous abdominal surgery, aortic dissection, and lymphangioleiomyomatosis can lead to silent occlusion of retroperitoneal lymphatic trunks. Percutaneous thoracic duct catheterization and embolization is safe and can replace surgical ligation in some patients.

Diagnosis and treatment of postoperative chyle leakage via percutaneous transabdominal catheterization of the cisterna chyli: a preliminary study

PURPOSE

To assess the feasibility of percutaneous transabdominal puncture and catheterization of the cisterna chyli or lymphatic ducts (PTCLD) in patients with postoperative chyloperitoneum and chylothorax, and to identify and possibly embolize the chylous fistula.

MATERIALS AND METHODS

Five patients had postoperative uncontrolled chyle fistulas. Two patients with chylothorax had thoracic duct (TD) ligation after esophagectomy and neck surgery. The other three patients had chylous ascites after surgery of the pancreas, the aorta, and the esophagus, respectively. After lymphographic opacification, the cisterna chyli (CC) or retroperitoneal lymph ducts were punctured transabdominally with a 21-gauge needle and catheterized with a 3-F catheter to reach the TD if possible. Microcoils were used to embolize a TD laceration.

RESULTS

Lymph ducts as small as 2-3 mm were catheterized successfully in three patients. The TD was catheterized in two patients; one TD fistula was embolized with cure of chylothorax. In one patient with a surgically tied TD, duct occlusion was confirmed despite continued pleural effusion. Three fistulas, not seen with lymphography, were identified in two of three chylous ascites and one chylothorax. There was no morbidity. As a result of this procedure, four of five patients did not require repeated operation.

CONCLUSIONS

PTCLD in the study of chyle fistulas was feasible and safe in the management of five patients and clinically useful in four patients; transabdominal catheter lymphography with aqueous contrast medium is more sensitive than pedal lymphography. Further evaluation is necessary.

Percutaneous transthoracic duct catheterization to the neck and esophagus: a feasibility study

PURPOSE

To assess the feasibility of inserting a drain catheter percutaneously from the cisterna chyli (CC) through the thoracic duct (TD) wall to the neck or esophagus for potential long-term T-cell sampling or drainage in acute or short-term experiments.

MATERIALS AND METHODS

Percutaneous transabdominal catheterization of the TD from the CC was performed in four animals to insert a 65-cm, 21-gauge needle over a microguidewire. In two dogs, the distal TD was perforated into the neck to connect the TD drain to an access port. In acute experiments on two swine, the esophagus was accessed by puncturing an intraluminal Foley-catheter balloon through the mid TD wall. In one animal, the TD catheter tip was left to drain in the distal esophagus; in the other animal, the catheter distal tip was pulled back through a gastrostomy until the proximal end had retracted into the proximal TD.

RESULTS

TD-to-neck port connection was well tolerated short-term. One dog developed dehiscence over the port at 10 days necessitating its removal; in the other dog, the whole drain retracted into the neck from the proximal TD. The technique for TD-to-esophagus catheterization in swine was feasible with no acute complications or mediastinal leakage of contrast medium.

CONCLUSIONS

Transabdominal percutaneous inside-out TD puncture for drainage to a neck port or to the esophagus is feasible in dogs and swine, respectively.