Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction.

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

Transhepatic inferior vena cava recanalization in a case of Budd Chiari syndrome: A novel approach.

Sharp recanalization for short-segment intravascular occlusion, using an endovascular route, has been described for inferior vena cava (IVC) occlusion. Often, the technical challenge to the endovascular management of Budd-Chiari syndrome (BCS) is the recanalization of the occluded hepatic vein or suprahepatic IVC. Presented here, the challenge was the level of occlusion of the suprahepatic IVC, with the resultant separation of both the patent IVC segments in a horizontal plane, making it technically challenging for sharp recanalization. We describe the use of percutaneous transhepatic access into the suprahepatic IVC via the middle hepatic vein under ultrasound guidance with eventual sharp recanalization of the occluded segment of the IVC, in a woman with BCS. This novel approach has not been described in the literature and can serve as an important addition to guide complex suprahepatic IVC recanalization.

Takotsubo cardiomyopathy after microwave ablation of hepatocellular carcinoma.

Takotsubo cardiomyopathy is a form of stress cardiomyopathy that can clinically mimic an acute ST-segment elevation myocardial infarction (STEMI). It involves transient anomalies in left ventricular wall motion secondary to myocardial stunning. Specific causes have still not been elucidated, and several mechanisms have been proposed, including catecholamine surges following intense emotional or physical stress. We present a case of a 74-year-old woman, diagnosed with Takotsubo cardiomyopathy following percutaneous microwave ablation of hepatocellular carcinoma. Although Takotsubo cardiomyopathy comprises a small percentage of acute coronary syndrome presentations, it should be considered in the differential for acute cardiac events as its management varies compared to other more common forms of acute cardiac events.

Portal Interventions in the Setting of Venous Thrombosis or Occlusion.

Portal vein thrombosis most commonly occurs as a complication of liver cirrhosis and can result in worsening symptoms of portal hypertension, which often can be challenging to treat with conventional decompression therapies. In addition, because complete portal vein thrombosis is associated with higher posttransplant morbidity and mortality, it is regarded as a relative contraindication to liver transplant. Often, the diagnosis of portal vein thrombosis is incidental; hence, imaging remains the mainstay for diagnosing this complication and is used to guide subsequent treatment. Although anticoagulation is the initial approach used to treat acute portal vein thrombosis, endovascular and/or surgical interventions may be necessary when there is concern for impending bowel ischemia. Treatment of chronic portal vein thrombosis is primarily aimed at alleviating the symptoms of portal hypertension and improving the chance of candidacy for liver transplant. Awareness of the portal venous anatomy to differentiate it from the periportal collaterals is key during recanalization of a chronically occluded portal vein. The authors provide an overview of the pathophysiology, acute and chronic imaging findings, and management of portal vein thrombosis, with a specific focus on endovascular management, as well as a summary of the current related literature. An invited commentary by Lopera and Yamaguchi is available online. ©RSNA, 2022.

Intrahepatic renal cell carcinoma implantation along a percutaneous biopsy and cryoablation probe tract.

A man in his 60s underwent percutaneous biopsy and cryoablation of a right upper pole clear cell renal cell carcinoma followed by repeat cryoablation 8 months later for possible residual disease. The patient was followed with imaging with documented stability for 19 months after repeat ablation. However, imaging at 32 months demonstrated intrahepatic nodular enhancing lesions along the initial percutaneous biopsy and ablation tract, consistent with metastatic implantation. The patient underwent repeat percutaneous biopsy and two rounds of microwave ablation for treatment of the intrahepatic implants, with no residual disease at 10 months postablation. While needle tract seeding is a known complication of percutaneous manipulation of various abdominopelvic malignancies, there have been no prior reports of intrahepatic metastatic implants related to percutaneous renal cell carcinoma ablation. Awareness of this potential complication is important for treatment planning, informed consent and surveillance. This report shares our experience of the management of intrahepatic metastatic implants.

Radiological correlation of mechanism of intravascular migration of the ventriculoperitoneal shunt and technical considerations for endovascular retrieval.

Migration of ventriculoperitoneal shunt into the pulmonary artery is a rare complication that can lead to shunt malfunction and cardiopulmonary complications. This case illustrates the significance of accidental transvenous placement of the shunt. Identification of the transvenous course of the catheter on cross sectional imaging can predict future catheter migration and also aid at surgical extraction. Formation of knot within the distal portion of the shunt catheter during migration or endovascular retrieval can occur, therefore measures to retrieve with knot and adhesions should be factored in before.

Feasibility of Creation of an Endovascular Arteriovenous Fistula in Patients Undergoing Preoperative Vascular Mapping.

Background: The first endovascular arteriovenous fistula (endoAVF) device (WavelinQ), a novel percutaneous technique of AVF creation, was approved by the Food and Drug Administration in 2018 and has been placed in a small number of United States patients on hemodialysis. It is unknown how often patients with advanced CKD have vascular anatomy suitable for WavelinQ creation. The goal of this study was to determine the proportion of patients with vascular anatomy suitable for WavelinQ creation and to assess patient characteristics associated with such suitability. Methods: All patients referred for vascular access placement at a large academic medical center underwent standardized preoperative sonographic vascular mapping to assess suitability for an AVF. During a 2-year period (March 2019 to March 2021), we assessed the suitability of the vessels for creation of WavelinQ. We then compared the demographic characteristics, comorbidities, and vascular mapping measurements between patients who were or were not suitable for WavelinQ. Results: During the study period, 437 patients underwent vessel mapping. Of these, 51% of patients were eligible for a surgical AVF, and 32% were eligible for a WavelinQ AVF; 63% of those suitable for a surgical AVF were also suitable for a WavelinQ AVF. Patients with a vascular anatomy suitable for WavelinQ were younger (age 55±15 versus 60±14 years, P=0.01) but similar in sex, race, diabetes, hypertension, coronary artery disease, and peripheral artery disease. Conclusions: Among patients with CKD with vascular anatomy suitable for a surgical AVF, 63% are also suitable for a WavelinQ endoAVF. Older patients are less frequently suitable for WavelinQ.

De Novo Central Vein Stenosis in Hemodialysis Patients Following Initial Tunneled Central Vein Catheter Placement.

Background: Central vein stenosis (CVS) is a common complication in hemodialysis patients following tunneled central venous catheter (CVC) insertion. Little is known about its incidence, association with patient characteristics, or relationship with duration of CVC placement. We systematically evaluated central vein stenosis in hemodialysis patients receiving their first CVC exchange at a large medical center. Methods: All new hemodialysis patients underwent an ultrasound before their internal jugular tunneled CVC placement, to exclude venous stenosis or thrombosis. After the initial CVC insertion, if the patients were referred for CVC exchange due to dysfunction, a catheterogram/venogram was performed to assess for hemodynamically significant (≥50%) central vein stenosis. During a 5-year period (January 2016 to January 2021), we quantified the incidence of CVS in patients undergoing CVC exchange. We also evaluated the association of central vein stenosis with patient demographics, comorbidities, and duration of CVC dependence before exchange. Results: During the study period, 273 patients underwent exchange of a tunneled internal jugular vein CVC preceded by a catheterogram/venogram. Hemodynamically significant CVS was observed in 36 patients (13%). CVS was not associated with patient age, sex, race, diabetes, hypertension, coronary artery disease, peripheral artery disease, or CVC laterality. However, the frequency of CVS was associated with the duration of CVC dependence (26% versus 11% for CVC duration ≥6 versus <6 months: odds ratio (95% CI), 3.17 (1.45 to 6.97), P=0.003). Conclusions: Among incident hemodialysis patients receiving their first tunneled internal jugular CVC exchange, the overall incidence of de novo hemodynamically significant central vein stenosis was 13%. The likelihood of CVS was substantially greater in patients with at least 6 months of CVC dependence.

Dialysis access-associated steal syndrome with percutaneous endovascular arteriovenous fistula creation.

BACKGROUND: Dialysis access-associated steal syndrome (DASS) is an infrequent complication after hemodialysis access creation. Clinical symptoms depend on the degree of steal. Percutaneous arteriovenous fistula creation offers a minimally invasive alternative to surgical creation, though complications have been reported. The following presents the first described case of DASS after percutaneous endovascular arteriovenous fistula creation, and discusses risk factors and management. CASE PRESENTATION: Our case is that of a 27-year-old male with end stage renal disease due to congenital renal dysplasia, who underwent left percutaneous arteriovenous fistula creation for initiation of dialysis. Two months after the procedure the patient complained of coldness, pain, tingling, and numbness in the left arm during dialysis, concerning for steal syndrome. The patient subsequently underwent brachial artery angiogram, which showed minimal antegrade flow through the ulnar and interosseous arteries towards the hand, and a focal, severe stenosis in the distal ulnar artery. Angioplasty of the stenosis was performed, though steal symptoms continued. CONCLUSIONS: DASS, though rare, can be seen with percutaneous arteriovenous fistula creation. Identification of the risk factors prior to creation can help avoid this complication. Management is largely guided by clinical presentation. As long as there is adequate collateral supply to the extremity, single vessel occlusion is not a contraindication to percutaneous arteriovenous fistula creation with the use of WavelinQ technology. Careful patient selection with pre-creation angiogram may reduce the risk of symptomatic steal.

An analysis of potential predictors of tunneled hemodialysis catheter infection or dysfunction.

PURPOSE: To assess the ability of various clinical factors to predict infection or dysfunction of tunneled hemodialysis catheters. METHODS: A retrospective review of all adult patients who had a tunneled hemodialysis catheter placed between 2012 and 2016 was performed. Tunneled hemodialysis catheters were considered infected based on clinical suspicion or culture-positive bacteremia. Dysfunction was defined as all other non-infectious causes for line failure. Time-to-removal or exchange was recorded. Clinical parameters analyzed as potential predictors of tunneled hemodialysis catheter infection or dysfunction, included the following: age, sex, site of placement, inpatient versus outpatient status at time of placement, body mass index, Charlson Comorbidity Index, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, platelet count, white blood cell count, international normalized ratio, and partial thromboplastin time. RESULTS: A total of 177 patients (95: female, 82: male; 71.7%: African American; mean age: 54.9 years) qualified for inclusion. The internal jugular vein was the site of placement in 97.1% of patients with 79.7% of lines being placed on the right side. One patient (0.5%) had minor bleeding after catheter insertion but no other complications were recorded. A total of 17 patients (9.6%) had lines removed or exchanged due to infection at a median of 86 (range: 13-626) days, while 68 patients (38.4%) had lines removed or exchanged due to dysfunction at a median of 42 (range: 1-531) days. A total of 92 patients (51.9%) had lines removed due to completion of therapy at a median of 68 (range: 7-433) days. Dysfunctional lines had a shorter time-to-removal than successful lines (p = 0.007). No difference was seen in time-to-removal between infected lines and successful lines (p = 0.16). Multivariate analysis showed that female sex (p = 0.003) and left-sided line placement (p = 0.007) were independent predictors of line dysfunction. No evaluated factors were predictive of tunneled hemodialysis catheter infection. CONCLUSION: Female sex and left-sided line placement were independent predictors of tunneled hemodialysis catheter dysfunction, but none of the evaluated parameters predicted tunneled hemodialysis catheter infection.

Chromosomal evidence for a new cryptic species of black fly in the Simulium praelargum complex (Diptera: Simuliidae) from West Bengal, India.

Analyses of polytene chromosomes revealed a new cryptic species of black fly, Simulium praelargum "IL", in the Simulium (Nevermania) feuerborni group from Darjeeling, West Bengal, India. This new species occurred sympatrically with two other previously recognized species in the S. praelargum complex: Simulium praelargum Datta sensu stricto and Simulium praelargum "IIIL-1.2". Chromosome arms IS, IIS, IIL, and IIIS of the new species showed no differences in banding patterns, compared with the sequences in Simulium praelargum s. s. and Simulium praelargum "IIIL-1.2". Chromosome arm IIIL of the new species was identical to that of S. praelargum s. s., but differed from that of S. praelargum "IIIL-1.2" by two fixed inversions. Chromosome arm IL of the new species differed from that of both species by four fixed inversions: IL-1, IL-2, IL-3, and IL-4. The new species and S. praelargum s. s. lacked a chromocenter, which was present in S. praelargum "IIIL-1.2". Sex chromosomes of the new species were cytologically undifferentiated (X0X0, X0Y0) and all specimens were monomorphic for autosomal inversion polymorphisms. Speciation in the S. feuerborni group, unlike in many other simuliid taxa, did not involve cytological differentiation of sex chromosomes.

Comparative Analysis of Intranodal Lymphangiography with Percutaneous Intervention for Postsurgical Chylous Effusions.

PURPOSE: To evaluate clinical success and time to resolution of intranodal lymphangiography (INL) alone or with thoracic duct embolization (TDE) or thoracic duct disruption (TDD) based on initial effusion volume for postsurgical chylothorax. MATERIALS AND METHODS: Retrospective review was performed of 57 patients (mean age 63 y; 65% male) undergoing INL alone or in conjunction with other percutaneous techniques for postsurgical chylous effusions. INL alone was performed when chylothorax output was ≤ 500 mL/d and no leak was identified during fluoroscopy. RESULTS: INL was technically successful in all patients. There was 1 major and 2 minor complications. Clinical success rate was 71% (40/56). Clinical success rate meeting algorithmic inclusion criteria was 71.4% (5/7) for INL only, 41.7% (5/12) in INL with TDD, and 90.5% (19/21) in INL with TDE. Hazard ratio (HR) of clinical success of INL with TDE versus INL only was not statistically significant (HR 2.3, 95% confidence interval [CI], 0.70-5.87, P = .19). Median time to resolution was 14 days for INL only (95% CI, 0 days to not reached), 7 days for INL with TDD (95% CI, 4 days to not reached), and 3 days for INL with TDE (95% CI, 2 to 5 days) (P = .007). No statistically significant difference in median time to resolution existed between INL with TDE and INL only (P = .04). CONCLUSION: In patients with postsurgical chylothorax, INL alone had similar rates of clinical success and time to resolution compared with INL with TDE when initial effusion volume was ≤ 500 mL/d and no leak was visualized during fluoroscopy.

Percutaneous Hepaticojejunostomy Using a Radiofrequency Wire for Management of a Postoperative Bile Leak.

Postoperative biliary complications following extensive hepatic resections are complex, often requiring a multidisciplinary team approach. We describe a case of a free bile duct leak following extended right hepatectomy and surgical hepaticojejunostomy treated with percutaneous transhepatic hepaticojejunostomy in which a radiofrequency guidewire was used to gain enteral access. A modified internal/external biliary catheter was left in place. The patient was enrolled in a benign biliary stricture protocol, and 8 months later, the catheter was removed following a normal cholangiogram and biliary manometric perfusion testing. At 3-month follow-up after catheter removal, the patient is asymptomatic with no clinical, biochemical, or radiographic evidence of biliary leak or obstruction.

Mediastinal Hibernoma: A Rare Case with Radiologic-Pathologic Correlation.

Hibernomas, especially located in the mediastinum, are extremely rare benign tumors, which are important to consider in the differential diagnosis of a heterogeneously enhancing mass with areas of fat attenuation on imaging of an often incidentally discovered mass. Other common possibilities in the differential include malignant tumors, such as liposarcoma, hence histopathology is usually required to confirm the diagnosis. Hibernomas often follow the distribution of sites of persistence of brown fat in adults, and intrathoracic locations are unusual. We present a very rare case of a mediastinal hibernoma in a 53-year-old woman. She presented to the emergency department with severe, progressive right neck and shoulder pain with radiation down her arm and was found to have a right apical posterior mediastinal mass on imaging. Initial radiographs of the shoulder showed a soft tissue mass within the apical right hemithorax. Further imaging with CT revealed a well circumscribed, heterogeneously enhancing mass with areas of fat attenuation. Pathology confirmed the diagnosis of mediastinal hibernoma, and the mass was completely excised. Fourteen months after surgery, the patient had a normal chest radiograph, and thirty-two months after surgery, she remains asymptomatic.

Sensitivity of endoscopic ultrasound, multidetector computed tomography, and magnetic resonance cholangiopancreatography in the diagnosis of pancreas divisum: a tertiary center experience.

OBJECTIVES: There are limited data comparing imaging modalities in the diagnosis of pancreas divisum. We aimed to: (1) evaluate the sensitivity of endoscopic ultrasound (EUS), magnetic resonance cholangiopancreatography (MRCP), and multidetector computed tomography (MDCT) for pancreas divisum; and (2) assess interobserver agreement (IOA) among expert radiologists for detecting pancreas divisum on MDCT and MRCP. METHODS: For this retrospective cohort study, we identified 45 consecutive patients with pancreaticobiliary symptoms and pancreas divisum established by endoscopic retrograde pancreatography who underwent EUS and cross-sectional imaging. The control group was composed of patients without pancreas divisum who underwent endoscopic retrograde pancreatography and cross-sectional imaging. RESULTS: The sensitivity of EUS for pancreas divisum was 86.7%, significantly higher than the sensitivity reported in the medical records for MDCT (15.5%) or MRCP (60%) (P < 0.001 for each). On review by expert radiologists, the sensitivity of MDCT increased to 83.3% in cases where the pancreatic duct was visualized, with fair IOA (κ = 0.34). Expert review of MRCPs did not identify any additional cases of pancreas divisum; IOA was moderate (κ = 0.43). CONCLUSIONS: Endoscopic ultrasound is a sensitive test for diagnosing pancreas divisum and is superior to MDCT and MRCP. Review of MDCT studies by expert radiologists substantially raises its sensitivity for pancreas divisum.

The salivary gland chromosomes of the Himalayan black fly Simulium (Simulium) dentatum (Diptera: Simuliidae).

Proper identification of the black files is facilitated by chromosomal characteristics when morphotaxonomic parameters are Insufficient to distinguish a species. Using photo composites, we constructed and describe from the salivary glands of larvae a standard polytene chromosome map of a Himalayan black fly, Simulium (Simulium) dentatum, in the multistriatum group (Diptera: Simuliidae). This species has three metacentric polytene chromosomes (n=3), with homologues more or less Intimately paired and having a prominent centromere. The largest chromosome (I) was 40.55% of total complementary length (TCL); chromosomes II and III were 30.14% and 29.31%, respectively. Chromosome I is characterized by the presence of a prominent nucleolar organizer at IS 19. Chromosome II is characterized by the presence of a Balbiani ring at MS 41B, followed by bulge and a Parabalbiani ring at IIL 64 B. Prominent homogeneously stained centromeres of chromosomes I, II, and III lie at the map positions L21A, L55, and L84, respectively.

Higher incidence of persistent chronic infection of Chlamydia pneumoniae among coronary artery disease patients in India is a cause of concern.

BACKGROUND: There is growing evidence that Chlamydia pneumoniae may be involved in the pathogenesis of atherosclerosis, as several studies have demonstrated the presence of the organism in atherosclerotic lesions. C. pneumoniae infections, which are especially persistent infections, have been difficult to diagnose either by serological methods or isolation of the organism from the tissue. Nucleic Acid Amplification tests (NAATs) has emerged as an important method for detecting C. pneumoniae. Inspite of high prevalence of C. pneumoniae specific antibodies in coronary heart disease patients, direct detection of C. pneumoniae in circulating blood of coronary artery disease (CAD) patients by sensitive nucleic acid amplification tests nested PCR (nPCR), multiplex PCR (mPCR) has not been carried out is required. Further correlation of the presence of C. pneumoniae in blood of CAD patients with C. pneumoniae specific IgA and IgG antibodies, which may indicative of the status of infection with the progression of atherosclerosis. This will help in order to prepare strategies for the antibiotic intervention to avoid the progression towards CAD. METHODS: Venous blood was obtained from 91 CAD patients and 46 healthy controls. Nucleic acid amplification tests viz. nested-, semi-nested- and multiplex PCR were used for detection of C. pneumoniae. ELISA carried out prevalence of C. pneumoniae specific IgG and IgA antibodies. RESULTS: 29.67% (27/91) patients were positive for C. pneumoniae using nested PCR. The sensitivity and specificity of semi-nested and multiplex PCR were 37.03%, 96.96% and 22.22%, 100% with respect to nested PCR. Positive nPCR patients were compared with presence of C. pneumoniae specific IgA, IgA+IgG and IgG antibodies. Among 27 (29.67%) nPCR C. pneumoniae positive CAD patients, 11(12%) were IgA positive, 13(14.2%) were IgA+IgG positive and only1 (1.1%) was IgG positive. A significant presence of C. pneumoniae was detected in heavy smokers, non-alcoholics and with family histories of diabetes and blood pressure group of CAD patients by nPCR. CONCLUSION: The results indicate synergistic association of C. pneumoniae infection and development of CAD with other risk factors. We also detected increased positivity for C. pneumoniae IgA than IgG in nPCR positive CAD patients. Positive nPCR findings in conjunction with persisting high C. pneumoniae specific antibody strongly suggest an ongoing infection.