Cava Syndrome Research Articles

Development of adult Dirofilaria immitis worms in the Rag2/Il-2rγ-/- mouse model

Dirofilaria immitis is the causative agent for one of the major parasitic infections in dogs. It is currently not possible to reliably diagnose the infection before the development of fertile adult female worms and the presence of microfilariae which takes six to 7 months. However, at this point adult worms already reside in the pulmonary arteries and can cause significant damage. Novel in vivo models may facilitate the development of new diagnostic tools and improve treatment options for both the early and late stages of D. immitis infections. In this paper, we aimed to increase the capabilities of recently published mouse models in which severely immune-deficient mice were shown to be susceptible to D. immitis. Our data shows that D. immitis may grow into fully developed mature male and female worms in C57BL/6 Rag2/Il-2rγ-/- mice with comparable growth rates to the natural canine host. The adult worms of D. immitis were shown to migrate into body cavities as well as the heart in this model. However, the presence of adult worms inside the heart of infected mice led to the development of caval syndrome in 36% of infected mice after five to 6 months. Overall, the current study complements recently published efforts to establish a D. immitis mouse model by extending the development of D. immitis into mature adult stages and will facilitate further preclinical research.

Efficacy and tolerability of the American Heartworm Society therapeutic protocol in dogs affected by heartworm disease without caval syndrome.

The American Heartworm Society medical protocol represents the current standard of therapy for canine heartworm disease without caval syndrome. However, data on the tolerability of this protocol are limited. This study aimed to describe efficacy and prevalence of possible treatment-related side effects in dogs with heartworm disease treated using the American Heartworm Society protocol. For this retrospective multi-centre cohort study, dogs diagnosed with classes 1 to 3 heartworm disease that completed the American Heartworm Society medical protocol were searched in four medical databases. Demographic, clinical, diagnostic, therapeutic and outcome data, including the number and type of possible treatment-related side effects, were retrieved. Thirty-five dogs were included. The median age and bodyweight were 6 years (1 to 13 years) and 17.3 kg (4.9 to 50 kg), respectively. Heartworm disease was classified as classes 1, 2 and 3 in 20 of 35, 11 of 35 and four of 35 dogs, respectively. In addition to the therapeutic recommendations of the American Heartworm Society, eight of 35 dogs underwent sedation to favour melarsomine administration, and 30 of 35 received ice at the injection site. After adulticide therapy, all dogs were hospitalised with cage rest [median time 12 hours (6 to 48 hours)]. All dogs survived the treatment. All dogs with long-term follow-up (32/35) became negative. Furthermore, treatment-related side effects were rare, mild and rapidly recovered without the need for supporting therapies; these included depression/lethargy (4/35 dogs), cough (2/35 dogs) and lameness, pain and gastrointestinal signs (1/35 dog each). The American Heartworm Society medical protocol is efficient and safe in dogs with classes 1 to 3 heartworm disease.

Management and outcome of intracardiac heartworms in dogs

BackgroundIntracardiac heartworm (IH) disease is a serious condition that can become life threatening if the patient develops caval syndrome. We aim to describe the management and outcome of IH in dogs evaluated by Medvet’s New Orleans cardiology service from November 2015 to December 2021.MethodsRecords of 27 dogs with IH were examined retrospectively. Follow-up information was obtained from phone conversations with referring veterinarians and owners.ResultsNine of 27 dogs had a previous diagnosis of heartworm disease and were undergoing “slow kill” treatment; 12/27 dogs' heartworm disease was a new diagnosis, and 6/27 had either scheduled or started adulticide therapy. Nine dogs had heartworm extraction. No dogs died during the heartworm extraction procedure. Four of 9 dogs have died (survival time 1; 676; 1815 and 2184 days). One dog died the day after the procedure secondary to continued respiratory distress; the other three died of non-cardiac causes. Five of nine are alive (median follow-up 1062 (range 648–1831) days. Eleven dogs had IH resolution. In 7/11 this occurred while undergoing stabilization for heartworm extraction. In 4/11 heartworm extraction was not recommended because of low IH burden. All dogs with IH resolution were discharged from the hospital. Four of 11 have died (survival time 6; 22, 58 and 835 days), and 6/11 are alive (median follow-up 523 (range 268–2081) days. One was lost to follow-up after 18 days. Five dogs were medically managed. In one of five dogs, extraction was not recommended because of low IH burden. In four of five extraction was recommended but declined. One of five has died (survival 26 days), and four of five are alive (follow-up 155, 371, 935 and 947 days). Two dogs were killed at the time of diagnosis. Fifteen of 27 dogs were considered to have caval syndrome.ConclusionThe results suggest that patients with IH resolution have a good long-term prognosis. Most often IH resolution occurred while the dog was undergoing stabilization for heartworm extraction. When IHs are present, heartworm extraction should still be considered the treatment of choice and recommended as first-line therapy whenever possible.Graphical

Evaluation of improved transvenous heartworm extraction brush in dogs with caval syndrome.

Heartworm infection in dogs is caused by Dirofilaria immitis and common in shelter animals and outdoors dogs. Caval syndrome can develop with severe infection and physical heartworm removal is essential with heartworm burdens. In this study, we used an improved transvenous heartworm extraction brush, which was expected to cause less cardiovascular damage and allow easier manipulation. This study aims to evaluate efficacy of this improved transvenous heartworm extraction brush. The brush was designed to improve upon the limitations of the previous brush-type devices. The brush was made of a polyvinyl chloride tube and threads of polyamides or polyglyconates. Metal material was inserted at the front tip for easy visualization under fluoroscopy. The eight dogs diagnosed with caval syndrome with large numbers of heartworms and pulmonary hypertension were used in this study. The removal procedure began with the dissection of the subcutaneous tissue around the right jugular vein. The device was inserted through the jugular vein. After insertion, the tube was rotated to catch the heartworms and extracted with the heartworms hanging on the threads. The procedure was repeated several times. Lastly, jugular vein and skin sutures were made. Adulticidal therapy was administered after heartworm removal. The mean number of removed heartworms was 10.5 ± 4.24 and mean number of remaining heartworms was 0.63 ± 1.06. Total procedure time was 72.63 ± 51.36. Except for three cases, heartworms were not detected on ultrasonography after the procedure. No procedure-related side effects were observed within the 1- to 2-mon. An improved transvenous heartworm extraction brush is efficient for heartworm removal in dogs with caval syndrome.

The wedge sign: A possible lung ultrasound sign for pulmonary thromboembolism.

To describe the finding of the lung ultrasound (LUS) "wedge sign" in dogs with presumptive pulmonary thromboembolism (PTE). This case series describes 2 dogs with predisposing risk factors of (1) right transvenous pacemaker terminating in its right ventricle, severe protein-losing nephropathy, and glucocorticoid therapy, and (2) caval syndrome, each having the LUS "wedge sign" in upper lung regions, a sign consistent with pulmonary infarction and peripheral PTE. Historically, the diagnosis of canine PTE has been made through supportive findings because the gold standard test, computed tomography pulmonary angiography (CTPA), poses limitations. The use of LUS has shown promise in people for detecting PTE, with the advantages of availability, being radiation- and contrast medium-sparing, rapid (<90s), point-of-care, real-time information. Our cases suggest a possible new first-line approach for suspecting canine PTE by using LUS and the finding of the "wedge sign" in nongravity-dependent caudodorsal and perihilar lung regions.

Catheter-related superior vena cava obstruction: A rare cause of chylothorax in maintenance hemodialysis patients.

With the extensive use of dialysis catheters in patients undergoing hemodialysis, superior vena cava (SVC) syndrome has gradually attracted attention in recent years. Chylothorax caused by SVC syndrome is rarely reported. In this paper, we report a case of chylothorax secondary to superior vena cava obstruction (SVCO) in a maintenance hemodialysis patient after multiple dialysis catheter placements. Relieving the SVCO through intravascular intervention could effectively treat chylothorax. In the past fourteen months, no recurrence of symptoms has been observed.

296 Case Report: Pacemaker Lead-Induced Fibrosis Resulting in Right Atrial and Tricuspid Stenosis Managed with An Open Surgical Approach

Abstract Pacemaker leads can result in localised inflammation and, over time, fibrosis. Rarely, this can significantly alter the anatomy of the heart and impair cardiac function. In this case, a fifty-year-old female had undergone pacemaker placement in her teens having experienced symptomatic bradycardia. Due to pacemaker pocket erosion, she had undergone a lead extraction where lead fragments had been left in-situ. Years after a new generator and leads were placed, she presented with symptoms of proximal venous congestion and superior vena cava (SVC) syndrome. A venogram demonstrated completely occluded brachiocephalic and innominate veins with significant adjacent venous collateralization. Computed tomography showed partial obstruction of the SVC and tricuspid stenosis. Initially, a decision was made not to intervene. After developing abdominal distension, she was diagnosed with hepatic congestion and cirrhosis secondary to elevated right sided pressures and right atrial congestion due to tricuspid stenosis. It was concluded that the patient’s symptoms were the result of occluded proximal veins, SVC syndrome, and functional tricuspid stenosis, all of which were likely the result of fibrotic tissue secondary to pacemaker lead-induced inflammation. Due to the severity of her symptoms, the patient accepted the risks associated with surgical management. Intra-operatively, electrocautery was used to debride the fibrotic tissue inhibiting the leaflets of the tricuspid valve. This worked to great effect and additional valve repair/replacement was not necessary. Whilst the patient has been left with SVC syndrome, her tricuspid stenosis symptoms are greatly improved. To our knowledge, such a case has not been previously described.

KAJIAN PUSTAKA: DIROFILARIASIS ANJING DAN KUCING KINI MEREBAK DI INDONESIA MERUSAK ARTERI PULMONALIS DAN PARU-PARU

Dirofilariasis, caused by Dirofilaria immitis, mostly known as heartworm disease, is an important mosquito-borne nematode zoonosis that naturally infects canids and other species such as cats, ferrets, and humans. There have been reports of heartworm infection from many countries in worldwide. Researchers have reported D. immitis is widely distributed in Southeast Asia because this parasitic zoonosis disease lives in temperate, tropical, and subtropical areas and can be found in colder regions. Therefore, the authors intended to provide an overview of Dirofilariasis cases in Indonesia from a global perspective. The published articles of dirofilariasis were collected and retrieved by an electronic literature search of three databases, including Google Scholar, PubMed, and Science Direct. The literature presented is intended to enhance our current understanding of the overview of D. immitis infection and its prevalence in Indonesia from a global perspective. D. immitis infection can cause caval syndrome in dogs as well as a cardiopulmonary syndrome known as Heartworm-Associated Respiratory Diseases (HARD), which can become fatal as the number of worms infecting the host increases. Whereas in cats, although the number of worms in the host are very few (one to six worms) they can cause pathological changes in the pulmonary arteries which result in a more serious infection than in dogs and endanger life.

Intracardiac heartworms in dogs: Clinical and echocardiographic characteristics in 72 cases (2010-2019).

BackgroundHeartworms, a cause of pulmonary hypertension (PH) in dogs, can migrate from the pulmonary arteries into the heart resulting in life‐threatening caval syndrome (CS).ObjectivesTo describe clinical and echocardiographic characteristics in dogs with intracardiac heartworms including estimated heartworm burden and frequency of PH and pigmenturia.AnimalsSeventy‐two client‐owned dogs with heartworms.MethodsRetrospective study. Data collected from an electronic medical records search for dogs with intracardiac heartworms included clinicopathologic, echocardiographic, and procedural findings. Dogs with heartworms isolated to the pulmonary arteries were excluded.ResultsEstimated intracardiac heartworm burden was low in 14 of 72 (19%) and high in 58 of 72 (81%) dogs. The majority were small breed (54/72; 75%; 29/72; 40% Chihuahuas) and had a high likelihood of PH (67/72; 93%). Pigmenturia was the second most common clinical finding (31/72; 43%) after lethargy (32/72; 44%). Anemia (37/55; 36%), pigmenturia (30/58; 52%), and bilirubinuria (28/36; 78%) were significantly more common in dogs with a high worm burden (P < .05). Based on the presence of anemia, pigmenturia, and clinical signs, 18 of 72 dogs (25%) were considered to have CS.Conclusions and Clinical ImportanceAlthough the majority of dogs with intracardiac heartworms had a high worm burden and high likelihood of PH, only 25% had clinical evidence of CS. Echocardiography is a useful tool to identify intracardiac heartworms, detect likelihood of PH, and could be useful for staging heartworm positive small breed dogs for intracardiac heartworm migration.

Abstract 16680: Endovascular Therapy of Svc Syndrome-a Systematic Review

Background: Superior vena cava (SVC) syndrome is caused by the occlusion of the SVC and can result in significant morbidity and mortality. Recently, endovascular therapy (ET) has become the standard of care for majority of these patients. We performed a systematic review of available literature to assess the contemporary technical success rate, restenosis rate, and recurrence rate of SVC syndrome following endovascular intervention. Methods: We searched PubMed, Cochrane Library, and Embase databases from 1988 to 2019 for studies on Endovascular Therapy for SVC syndrome. After screening 709 records, 13 studies were included. Screening was conducted using Rayyan QCRI software for systemic reviews. Studies included full-length journal articles on SVC syndrome and ET among adults (18+ years). Case reports, or case series with &lt;20 patients were excluded. Data analysis was performed using OpenMeta software. Proportions and 95% confidence intervals (CIs) were calculated using random effects models. Heterogeneity among studies was assessed using Q and I 2 statistics. We evaluated the end-points of the technical success, restenosis rate and recurrence rates in SVC syndrome patients after endovascular stenting Results: A meta-analysis of 13 studies included a total of 1024 patients. The results of our meta-analysis show a weighted technical success rate of 98.6% (95% CI 0.97 – 0.99) (Fig. 1A), restenosis rate of 11.8% (95 CI 0.08-0.14) (Fig 1B) and recurrence rate of 9.9% (95% CI 0.06-0.13) (Fig 1C). Our studies had a substantial heterogeneity (I 2 ) of 52-80%. Figures:Figure 1A Figure 1B Figure 1C Conclusions: Our systematic review revealed high technical success rate, low restenosis, and recurrence rates after endovascular therapy supporting the paradigm of endovascular therapy as first line treatment for patients with SVC syndrome. Disclosures: Dr. Bashir has equity interest in Thrombolex Inc.

Treatment of dogs with severe heartworm disease

Fortunately, the majority of dogs diagnosed with heartworm infection are asymptomatic (or have only mild symptoms such as intermittent cough) and go through adulticide therapy without complication. Complications occurring with heartworm infection and during its treatment most often directly reflect the pulmonary vascular and parenchymal injury inflicted by Dirofilaria immitis. Clinical signs may include exercise intolerance, frequent cough, hemoptysis, tachypnea, and dyspnea. Severe manifestations such as heart failure and caval syndrome may prove fatal. Acute hypersensitivity reactions after initiation of macrocyclic lactone preventive therapy in microfilaremic dogs or after melarsomine injection during adulticide therapy do occur, but are uncommon. This article reviews complications associated with heartworm infection.

Superior Vena Cava Syndrome from Percutaneous Right Ventricular Assist Device Use in Right Ventricular Failure

Percutaneous right ventricular assist device (RVAD) support with right internal jugular (IJ) vein access has emerged as a viable solution for treating refractory RV failure. Recent reports have shown that RVAD support with this approach can be beneficial in a variety of clinical scenarios including post cardiotomy RV failure, cardiogenic shock, and severe acute hypoxemic respiratory failure with associated RV dysfunction, as well as decreased mortality compared to surgically implanted RVADs. However, the safety profile of such devices has not been characterized. A comprehensive retrospective review was completed for all patients receiving percutaneous RVAD support via a right internal jugular route with either 28 or 31F cannula at our institution between April 2017 and December 2018. Preoperative patient demographics, intraoperative, and postoperative outcomes, with specific focus on device related complications. Fourty patients (27 men, 67.5%) with mean age of 52 years ± 15.6 and refractory RV failure were managed with a percutaneous RVAD inserted through the right IJ. Of these 40 patients, 3 (7.5%) patients demonstrated device related superior vena cava (SVC) syndrome resulting from obstruction of the SVC with the RVAD cannula. One patient managed by head of bed elevation and early removal of the device (I believe). Two were treated by connecting a "venting" tubing to the side port on the introducer sheath and placing into the ECMO circuit to for decompression. Symptoms resolved in all 3 patients and no deaths resulted from SVC syndrome. SVC syndrome related to percutaneous RVAD placement is an important, but previously undescribed postoperative complication of RVAD use. Early identification allows safe management of this complication, which does not detract from the safety of percutaneous RVAD support.

A CURIOUS CASE OF AN ELEVATED DIAPHRAGM CAUSING MARKED KINKING OF THE INFERIOR VENA CAVA

Inferior vena cava (IVC) syndrome is commonly due to obstruction from deep vein thrombosis or a mass effect. We present an unusual cause of IVC syndrome diagnosed by transthoracic echocardiography (TTE). A 74-year-old female with history of paraplegia and hypertrophic cardiomyopathy presented to

Malignant Rhabdoid Tumor of the Mediastinum: A Rare Variant of Thymic Carcinoma Presenting As Superior Vena Caval Syndrome

Malignant rhabdoid tumor (MRT) of the thymus is rare aggressive tumor and only 34 cases are reported in the literature till date. Index case report describes a middle adult, female, with superior vena caval syndrome and prevascular space mass on chest axial scan, and histological features revealing MRT of thymus and metastatic spread. Contrast-enhanced CT neck and chest revealed aggressive tumor causing severe narrowing of the right internal jugular and superior vena-caval junction. This case represents an example to consider MRT along with other tumors like lymphoma, germinoma and anaplastic carcinoma of thyroid in subjects with aggressive prevascular space mass, and to consider biopsy specimen evaluation rather aspiration cytology evaluation for evaluation of mediastinal masses.

Dirofilaria immitis infestation in imported police (K-9) dogs in Iraq:

Dirofilaria immitis, the cause of heartworm infestation (HWI) or dirofilariasis, affects members of the Canidae and remains a worldwide clinical problem. In Iraq, dirofilariasis was believed absent until 2009, when the Karbala Governorate was reported as an endemic area for canine dirofilariasis. Consequently, this study intended to investigate the occurrence of Dirofilaria immitis in police dogs in one police academy in Iraq and to study the gross and histopathological changes in 5 dead dogs, as well as to identify the species of the causative parasite using PCR technique. Thirty-nine police dogs, aged between 6 months and 12 years were included in this study. For the microfilariae investigation, 5 ml blood samples were collected from all dogs in EDTA tubes and examined by Knott’s method. The systemic necropsy performed in five dead dogs showed severe clinical signs of dirofilariasis and tissue specimens were sent for routine histopathological processing. For the molecular analysis, adult worms of the detected Dirofilaria spp. were used for DNA extraction andamplification of the cox1 gene. Fifteen of 39 (38.46%) dogs were diagnosed with moderate to severe microfilariasis. The dead dogs revealed typical severe clinical signs of dirofilariasis. Moreover, typical gross and histopathological changes were also seen, accompanied by generalized thromboembolic lesions, suggesting the occurrence of the caval syndrome. The PCR investigation confirmed that D. immitis was the species present in Iraq. In conclusion, this study establishes that Iraq is a newly reported endemic area for dirofilariasis. Moreover, the infestation occurring in these cases most probably happened inside Iraq. The authors recommend doing further epidemiological studies concerning the occurrence of D. immitis in local dogs as well as in the imported dogs in all Iraqi governorates to better understand the epidemiological map of this disease and to introduce an active treatment and preventive program. Awareness and education regarding this disease should be provided to the veterinarians, dog guiders and people in direct contact with dogs, as this disease is one of the important zoonotic diseases.

Evaluation of a structured individualised protocol as a potential cost-effective diagnostic and therapeutic approach to chronic diarrhoea in the dog.

Diagnostic investigation and management of chronic diarrhoea in dogs can be cost‐prohibitive to many owners. The objectives of this study were to evaluate evidence‐based, individualised diagnostic and therapeutic protocols for management of dogs with chronic diarrhoea, where financial constraints dictate a budget‐limited approach and where more expensive approaches are deferred until simple affordable protocols are unsuccessful. Twenty‐two client‐owned dogs with chronic (minimum 2 weeks duration) untreated small, large or mixed small/large bowel diarrhoea were enrolled in a budget‐limited step‐wise management protocol (maximum expenditure $300 over 6 weeks), with diagnostic testing and therapeutic trials managed in an individualised and evidence‐based fashion. Success was defined as complete resolution of diarrhoea for a minimum of 1 month. Dogs that failed to respond to a budget‐limited protocol were then enrolled for complete, referral‐level management. Four dogs exited the project early (one death due to caval syndrome, three lost to follow‐up). Thirteen out of the remaining 18 dogs had complete resolution of diarrhoea utilising a budget‐limited approach (success rate 72.2%, confidence intervals 46.5–90.3%) and five dogs were moved on to a referral‐level investigation, with complete resolution of diarrhoea in four out of five. Seventeen out of the 18 dogs therefore responded to a protocol based on a budget‐limited approach followed by extensive investigation only if needed, for an overall success rate of 94.4% (CI 72.7–99.9%). Comprehensive investigation of chronic diarrhoea can be deferred while simple affordable diagnostics and therapeutic trials are conducted in stable canine patients and, often, an extensive management approach will be unnecessary.

Underestimated awakening face-edema caused by a mediastinal syndrome

The syndrome is an oncological urgency but, in some situations as in the case report described below, it can present itself in a subtle and inextricable way with symptoms and signs that, if singularly evaluated, can be nonspecific. In particular, we report the case of facial edema and a rash that, developing in an unusual and progressive way during about 2 months, concealed a voluminous mediastinal formation due to the localization of non-Hodgkin B-cell lymphoma that caused a superior caval vein syndrome.

The role of chronic superior caval syndrome and stenosis of jugular veins in neurodegenerative diseases. Surgical treatment and preliminary results

The role of chronic superior caval syndrome and stenosis of jugular veins in neurodegenerative diseases. Surgical treatment and preliminary results

Διροφιλαρίωση του σκύλου: παθογένεια και διάγνωση ενός πολυδιάστατου νοσήματος

Canine heartworm disease (dirofilariosis) caused by Dirofilaria immitis is a parasitic disease frequently occurring in the para-Mediterranean countries. Global climate changes, animal transportation and inappropriate implementation of preventive measures in companion animals are some factors that have contributed to expansion of the disease in the last decades. Transmission of the parasite is carried out by mosquitoes, whilst the final hosts are members of the Canidae family or occasionally other animal species and humans. Apart from the endothelial lesions caused by the adult filariae, the endosymbiotic bacterium Wolbachia pipientis appears to play a role in the pathogenesis of the disease, through endotoxin production and production of specific IgG responses by the host against the bacterium’s surface proteins. Based on clinical and laboratory findings, dogs with the disease can be categorized into one of four clinical stages, ranging from asymptomatic to caval syndrome. Diagnosis of the disease can be reached after evaluation of clinical findings, in conjunction with paraclinical examinations, e.g., microfilarial and antigen testing, diagnostic imaging, haematological and blood biochemical examination.

From Anatomical Knowledge to Clinical Comprehension: a Peer-Oriented Learning Session to Help Medical Students Make the Leap

A number of active learning approaches are being used in medical schools and are shown to be effective for improving knowledge comprehension and retention. Here, we report the creation and successful implementation of an interactive activity that was created to help students to understand the concepts of anatomy. Our goal was to encourage them to think about human structure and function by demonstrating how anatomy is changed due to disease or trauma. This session consolidated clinically relevant concepts from different anatomy didactic sessions into one exercise. It also allowed application of basic anatomy principles to clinical scenarios by comparing normal thoracic anatomy with the trauma specimens such as those from chylothorax, traumatic aortic injury, superior vena cava (SVC) syndrome, and tracheobronchial injury with pneumomedistinum. The session was received very well by the students and resulted in their improved understanding and application of various principles of anatomy.