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Segmental caudal vena cava (CVC) aplasia is a rare congenital vascular anomaly in dogs. Two dogs were diagnosed by CT imaging to have right adrenal tumors with concomitant segmental CVC aplasia. During surgery, a firm connection between the right adrenal gland and CVC was observed in both cases. The adrenal glands were found ventral to the CVC and the adrenal tumor was resected including the vascular wall. CVC venectomy for tumor removal will be required if the right adrenal gland is displaced in dogs with segmental CVC aplasia, even if there is no intravascular invasion.

Three canines were identified with aberrant drainage of the caudal vena cava to the left atrium, consistent with imperforate cor triatriatum dexter, and concurrent patent foramen ovale. All three had concurrent significant pulmonic stenosis with varying degrees of hypoplasia of the right ventricular outflow tract. Echocardiography, positive contrast studies, and angiography confirmed the diagnosis. Surgical redirection of the caudal vena cava bloodflow to the right atrium was attempted unsuccessfully in two symptomatic patients. The third patient was asymptomatic, and correction was not attempted. Possible embryologic causes and possible approaches in future cases are discussed.

This report describes the successful placement of a nitinol stent within the azygos continuation of the caudal vena cava in a 2-year-old, neutered female, English Bulldog with clinical and imaging signs related to venous return chronic obstruction, renal venous thrombi, and chronic renal insufficiency. This noninvasive, interventional radiology procedure was safe and clinically effective for the patient. The clinical signs were rapidly eliminated, and three years later, the patient is still in good clinical condition, with normal renal function. Venous stenting appears to be a useful, new, minimally invasive treatment option for symptomatic cavo-azygos vascular connection.

The objective of this study was to calculate the collapsibility index (CI) in a group of 15 healthy adult mixed breed cats via right hepatic intercostal ultrasound view. The minimal and the maximal diameters of the caudal vena cava (CVC) were obtained during inspiration and expiration, respectively, then CI was calculated. The mean diameter of the CVC was 0.5cm. The mean CI was 28±3% and CI was not significantly associated with gender. As in human medicine, there is a growing need for less invasive monitoring in small animal practice. The CI enables the assessment of estimated volemia without the need for a central venous catheter. This is the first reported study investigating CI in cats. RESUMO O objetivo deste estudo foi calcular o índice de colapsabilidade (IC) em um grupo de 15 gatos adultos, saudáveis e SRD, por meio da janela ultrassonográfica hepática intercostal direita. Os diâmetros mínimo e máximo da veia cava caudal (VCC) foram obtidos durante a inspiração e a expiração, respectivamente. O IC foi calculado, posteriormente. O diâmetro médio da VCC foi de 0,5cm. O diâmetro médio do IC foi de 28±3%, e o IC não foi significativamente associado ao gênero. Como na medicina humana, há uma necessidade crescente de monitoramento menos invasivo na prática de pequenos animais. O IC possibilita a avaliação da volemia estimada sem a necessidade de um cateter venoso central. Este é o primeiro estudo relatado sobre IC em gatos domésticos.

A seven-month-old cat was referred for evaluation of exercise intolerance and open-mouth breathing. Based on ultrasonographic examination, caudal vena cava (CVC) aneurysm associated with right congestive heart failure resulting from congenital heart disease was diagnosed. Conservative treatment for alleviating pulmonary hypertension mildly improved the clinical signs and decreased the heart size and CVC aneurysm diameter. However, the improvements were transient and four months after initiating therapy, the cat developed dyspnea and uncontrollable seizures and was euthanized.

Background Circumcaval ureter is a rare congenital anomaly resulting from the persistence of embryonic venous system. This anomaly is characterized by running of affected ureter around caudal vena cava (CVC). Case presentation In this report, circumcaval ureter was found in a 2‐year‐old female cat attending as normal sample group in another research. This cat passed all health checkup protocols before computed tomography (CT) was performed. Conclusion The contrast‐enhanced computed tomographic (cCT) images clearly revealed the dislocation of the right ureter that course around CVC and uterine body. This is the first report of feline circumcaval concurrent with circumuterine ureter detected by cCT., In this report, we have found the circumcaval ureter in a 2‐year‐old female cat attending as normal sample group in another research. This cat passed all health checkup protocols before computed tomography (CT) was performed. The contrast‐enhanced computed tomographic (cCT) images clearly revealed the dislocation of the right ureter that course around CVC and uterine body. This is the first report of feline circumcaval concurrent with circumuterine ureter detected by cCT.

Background: Caudal vena cava generally travels from the abdominal cavity to the right atrium and visible on lateral thoracic radiograph. Dilation of Caudal vena cava is generally considered as an abnormality for diagnosis of right-side heart failure. Normal range of ratio of caudal vena cava to associated structures can help in differentiating normal dogs from abnormal dogs. The present study was aimed to find such ratio in normal dogs and their clinical relevance. Methods: The present study was conducted on 19 healthy dogs of either sex belonging to different age-groups presented to the Department. They were anaesthetized and subjected to thoracic radiography in standard positions. The width of caudal vena cava (CVC), the descending aorta (AO), right fourth thoracic rib (R4) and the length of thoracic vertebrae (VL) were measured in left lateral (LeL) radiographic views to calculate ratios like CVC/AO, CVC/VL, CVC/R4, AO/VL, AO/R4. Result: The results revealed a wider range of some of such ratios than those reported so far by other workers for healthy dogs. Moreover, a wide variation in shape of CVC and size of R4 was noticed in individuals. It is concluded that the existing range of such ratio needs to be modified for better clinical relevance and overall such ratios do not represent a sensitive diagnostic modality.

Chronically sustained systemic hypertension in dogs can damage the kidneys, eye, brain, heart, and vessels. In human medicine, systemic hypertension has been implicated as the most common risk factor for aorta dilation, which can progress to an aneurysm. Abdominal ultrasound has been commonly used to monitor the size of the abdominal aorta in people with systemic hypertension. In this retrospective cross-sectional abdominal ultrasound study, evaluation of the size of the abdominal aorta relative to the caudal vena cava was performed in 18 control dogs and 128 dogs with confirmed systemic hypertension. Preexisting conditions contributing to systemic hypertension in these dogs were renal disease, hyperadrenocorticism, diabetes mellitus, adrenal tumors, and previous administration of phenylpropanolamine or palladia. The abdominal aorta and caudal vena cava were assessed from longitudinal images cranial to the trifurcation with measurements made from outer border to outer border of the walls, being careful not to compress the caudal vena cava that would alter its size. Our hypothesis was the ratio of the diameter of the abdominal aorta to caudal vena cava would be higher in dogs with systemic hypertension compared to dogs with normal blood pressure. The mean abdominal aorta-caudal vena cava ratio was 1.028 in control dogs with a normal blood pressure and 1.515 in dogs with systemic hypertension. In dogs with confirmed systemic hypertension, the abdominal aorta was dilated compared to the caudal vena cava in the caudal abdomen. An increase in the abdominal aorta-caudal vena cava ratio in a dog should raise suspicion for the presence of systemic hypertension and prompt evaluation of blood pressure.

Objective To investigate whether the donation of 1 unit of blood results in a significant decrease in the caudal vena cava diameter (CVCd) and the caudal vena cava diameter to aortic diameter (CVCd:Aod) ratio measured at the iliac location. Interventions Eight healthy client-owned Greyhounds underwent ultrasound of their caudal vena cava and aorta before and after blood donation. The principal investigator obtained M-mode images of the blood vessels from all dogs and a secondary investigator measured the CVCd and aortic diameter in a blinded manner from stored images. The ratio of CVCd:Aod was then calculated. After assessing for normality, paired-sample t-tests were performed to compare mean values before and after donation. Main results The mean (±SD) CVCd before and after blood donation were 15.84 mm (±5.06 mm) and 15.82 mm (±5.42 mm) and the CVCd:Aod ratios were 0.93 (±0.23) and 1.00 (±0.27), respectively. There was no statistical difference between pre- and postdonation values for CVCd (P = 0.99) or CVCd:Aod (P = 0.34). Conclusion The measurement of CVCd and CVCd:Aod ratio with ultrasound at the iliac location failed to detect mild-to-moderate blood loss produced by the donation of 1 unit of blood in Greyhounds.

Computed tomography is increasingly used as a treatment planning method in canine patients with diseases of the retroperitoneum, however, published information on normal variations in the caudal vena cava (CVC) are currently lacking. The objectives of this retrospective descriptive study were to characterize CVC variants using CT angiography in a sample of small breed dogs and localize the CVC bifurcations for each variant. Inclusion criteria were small breed dogs (weight ≤ 15) that underwent contrast-enhanced CT scans of the CVC, abdominal aorta, and CVC tributaries. A total of 121 small breed dogs were sampled. Four right-sided and one left-sided CVC variations were identified: normal (88/121, 72.7%), caudal-partial split (17/121, 14.0%), partial duplication (8/121, 6.6%), complete duplication (7/121, 5.8%), and left-sidedness (1/121, 0.8%). The mean lumbar vertebral levels of the CVC bifurcation were L6.39 ± 0.41, L5.70 ± 0.35, L4.39 ± 0.42, L2.74 ± 0.38, and L6.4 in the normal, caudal-partial split, partial duplication, complete duplication, and left-sidedness types, respectively. The location of the CVC bifurcation, the relationship between the aortic trifurcation and the CVC bifurcation, and the location of the bilateral deep circumflex iliac veins with respect to the CVC bifurcation were significantly different among the right-sided types (P ≤ .001). Bilateral deep circumflex iliac veins joined to the ipsilateral common iliac veins and the CVC in the caudal-partial split and duplication types, respectively. The results of this study indicated that canine CVC variants may be frequent and should be considered during surgery or diagnostic imaging of the retroperitoneum.

Radiology, an imaging technique, is used in checking small animals for cardiovascular and respiratory disorders. Cardiovascular disease such as congestive heart failure, pericardial heart disease, heart worms and disease that cause injury and lesion in the right atrium may lead to an enlarged right side of the heart and as a result cause the enlargement of caudal vena cava (CVC). It is not possible to make a complete comparison of CVC size, due to variety in size of the cats but the ratio of CVC size to the other anatomical structures makes this possibility that we have a better estimation of CVC size. So the aim of this study was to evaluate the ratio of CVC size to aorta (Ao), width of fourth rib (R4) and also the thoracic vertebral length (VL) in 20 male healthy and 20 Domestic Shorthair (DSH) cats with right heart failure (RHF). To this end, the ratio of CVC size to posterior aorta (Ao), the ratio of CVC size to width of the forth rib, the ratio of CVC size to the length of thoracic vertebrae above the site of trachea bifurcation, CVC/VL of 20 RHF cats to CVC/VL of 20 healthy SHD cats, and also Ao/VL ratios were calculated. Statistical analysis showed significant difference in the CVC/Ao and CVC/R4 between healthy and RHF cats. CVC/VL was increased in RHF cats in comparison to healthy ones (P

Objectives Ultrasonography of the caudal vena cava (CVC) has been previously established to assess fluid status in dogs but not in cats. The aim of this study was to determine CVC diameter changes during feline blood donation. Methods Inter- and intra-observer variability were assessed in 11 client-owned cats. Minimal and maximal CVC diameters were assessed longitudinally in the subxiphoid view (SV) and right paralumbar view (PV), and transversely in the right hepatic intercostal view (HV). Eighteen client-owned, healthy, anaesthetised cats were evaluated during 21 blood donation procedures of 10 ml/kg in the same anatomical locations before (T0) and after (T1) blood donation, and after volume resuscitation with 30 ml/kg lactated Ringer’s solution (T2). The CVC index was calculated. Results Intra-observer variability was acceptable for all probe positions, except for the HV, whereas inter-observer variability was considered unacceptable for all probe positions. Complete measurements were obtained during 21 blood donations at T0, T1 and T2 at the SV, during 18/21 blood donations at the HV and during 16/21 blood donations at the PV. At the SV, the minimal CVC diameter between T1 and T2 ( P Conclusion and relevance Significant probe position dependent CVC diameter changes with marked overlap were observed before and after blood donation, and after fluid bolus. No absolute CVC diameter could be used to indicate hypovolaemia. Ultrasonographic assessment of the feline CVC is highly operator-dependent. The CVC index is not useful in cats.

This paper aimed to describe the main clinico-epidemiological, laboratory, and anatomopathological findings in 10 cattle affected with caudal vena cava thrombosis. The main clinical signs observed were decreased milk production, reduced appetite, apathy, impairment of ruminal motility, cardiorespiratory disorders (tachycardia and tachypnea), epistaxis, hemoptysis, and ascites. Intercurrent diseases such as mastitis, metritis, and phlebitis were verified. The hematological findings were mild anemia, leukocytosis due to neutrophilia with regenerative left shift, and hyperfibrinogenemia. The pathological exams revealed thrombi in the caudal vena cava, hepatomegaly, ascites, liver abscesses, pulmonary edema and emphysema, and abscesses in the lungs. The association of epidemiological information, clinical signs such as respiratory distress, epistaxis or hemoptysis, in addition to anemia and leukocytosis due to neutrophilia, as well as the occurrence of thrombus in the caudal vena cava as pathological findings, are indicative elements of the clinical picture of vena cava thrombosis in cattle. It is reiterated that this disease has an unfavorable prognosis and, when diagnosed, the animal must be culled.

Background Ultrasonographic measurement of the vena cava and aorta (Ao) diameters and their ratios have been suggested to be a reliable way of quantifying hypovolemia. Objective To evaluate the feasibility and reliability of an ultrasonographic technique for measurement of Ao and caudal vena cava (CVC) and derived ratios using three different acoustic windows in a population of healthy neonatal foals. Correlation between Ao and CVC measurements and ratios and foals' age or bodyweight were also investigated. Methods In 14 healthy foals aged less than 7 days, the diameters of the Ao and of the CVC in long and short axis were measured by two observers from images obtained using three different ultrasonographic imaging planes (left dorsal, left ventral and right views). The Ao and CVC cross‐sectional area and the CVC/Ao diameter and area ratios were calculated. Image quality was subjectively assessed. Intraobserver and interobserver reliabilities for image quality scores and measurements were evaluated between the two observers. Simple linear regression models were used to identify correlations between the CVC/Ao measurements and ratios and the age and bodyweight of the foals. Results The left ventral view showed the highest reliability. A correlation between bodyweight and the short axis measurement of the CVC was found (R 2 = 0.385; p = 0.018). Age was positively correlated with the long axis of measurement of the CVC (R 2 = 0.426; p = 0.011) and CVC/Ao diameter ratio (R 2 = 0.625; p = 0.001). Conclusions The left ventral view allows the Ao and CVC cross sections to be easily visualized and measured in neonatal foals in right lateral recumbency., The present study evaluated the feasibility and reliability of an ultrasonographic technique for measurement of Ao and CVC and derived ratios using three different acoustic windows in a population of healthy neonatal foals. A left ventral view of the abdomen allowed for rapid imaging and measurement of the cross‐sectional diameter of both the aorta and the CVC in neonate foals in lateral recumbency, and might be a promising method to quantitatively assess the degree of hypovolemia.

Retrocaval ureters form due to a congenital malformation of the caudal vena cava. This anomaly has been reported in cats and is usually incidental. Retrocaval ureters are rare in dogs, but have been associated with ureteral obstruction. When presented with a dog with hydroureter and hydronephrosis an obstructed retrocaval ureter should be considered as a rare differential. This case report describes a left retrocaval ureter causing ureterohydronephrosis, diagnosed by computed tomography.

An ultrasonography was performed in 21 healthy male calves of Nellore (n = 8), Curraleiro Pe-duro (n = 7) and Pantaneiro (n = 6) breeds, between 8 and 12 months, with the objective to display information about size, position and ultrasonographic parenchymal patterns of the liver, in addition to the topography of the gallbladder, right kidney and major vessels. The measurements used were dorsal margin distance (DMD) and ventral margin distance (VMD) of the liver, viewable extension (VE) of the liver, the caudal vena cava (CVC), width (CVCW) and depth (CVCD) and the portal vein (PV), width (PVW) and depth (PVD). The measures DMD, VMD and VE were similar, and the organ's longest visible extension was in 11th ICS. CVC was more frequently observed in the 11th and 10th ICS, despite being visible from the 12th to the 9th ICS in Nellore and still 8th ICS in Curraleiro Pe-duro and Pantaneiro. CVCD was lower in the 10th and 9th ICS in Nellore. The PV presented higher observation frequency in the 10th ICS. The measures PVD and PVW were higher in Nellore in the 11th, 10th and 9th ICS. To our knowledge, this report is the first to document ultrasonographic findings in three healthy calves. Considering the three breeds, the results show no differences in the ultrasonographic features as regard to the measurements and visualization of the position, size and vasculature of the liver and there was no additional information about the topography of the gallbladder and the right kidney.

The formation of the caudal vena cava is a complex process involving development, regression, and anastomosis. In mammals, the normal caudal vena cava runs to the right side of the abdominal aorta, while duplication of the caudal vena cava has been identified as a congenital abnormality in both companion animals and humans. The present study demonstrates that Slc:Hartley guinea pigs frequently possess asymptomatic duplicated caudal vena cava. The prevalence was 30% and 24% for males and females, respectively, with no sex-related differences. In accordance with Saad et al. (2012)’s criteria, duplicated caudal vena cava were classified into two distinct variations. The dominant variation was a complete duplication without iliac anastomosis where the left caudal vena cava continued from the left common iliac vein and joined the left renal vein; the left renal vein ran to the right to join the right caudal vena cava. The alternative variation was an incomplete duplication where the left caudal vena cava joined the right infrarenal caudal vena cava at a more cranial point than in normal cases; the renal segment was unchanged. Iliac anastomosis was not found in any cases. Duplicated caudal vena cava neither affected the body weight nor the kidney weight. In conclusion, Slc:Hartley guinea pigs frequently possess asymptomatic duplicated caudal vena cava in the absence of iliac anastomosis and appear to be a novel and useful animal model for duplicated caudal vena cava in animals and humans.

In dogs, variation in the branching pattern of renal veins is rare with only few patterns reported. This report describes two unusual anomalies of the renal vein branching patterns in two dogs. In dog 1, a common renal trunk drained both kidneys, in a T-shape pattern, in the caudal vena cava after a long right perirenal course. In dog 2, a common venous trunk branched cranially from the pre-renal segment of an azygos-caudal vena cava venous trunk and divided into the renal veins in a Y-shape pattern. Proper knowledge of the possible anatomical variations in renal venous drainage may be helpful during imaging assessment and surgical planning of several canine diseases involving the abdominal vasculature and retroperitoneal space.

Key Clinical Message This case highlights the management and diagnostic evaluation of a dog with two individually rare conditions (lung lobe torsion and vena cava aneurysm) that ultimately resulted in fatal pulmonary thromboembolism.

Objectives The aims of this study were to describe a method for the sonographic assessment of volaemia, to determinate inter- and intra-operator variability and to assess the ability to detect blood loss after blood donation in healthy dogs. Materials and Methods The left kidney was identified in a spleno-renal view, and transverse views of the caudal vena cava and aorta were obtained in 12 dogs. Vessel diameters were measured in B-mode, in duplicate by two operators, and the caudal vena cava:aorta ratio was calculated. Intra- and inter-operator variabilities were assessed using a Bland–Altman method by plotting the differences between the repeated measurements obtained from the same subject by the same operator and by the two operators against their means. Before and after blood donation measurements were compared using paired t-tests or one-sample t-tests, if appropriate. Results Intra- and inter-operator variability was within the limit of agreement for the vast majority of measurements. After a blood donation of 9·8 ±2·2 mL/kg, the mean aorta measurements were not significantly different from those obtained before blood donation (1·11 versus 1·10, P=0·28), whereas the mean caudal vena cava measurements and caudal vena cava:aorta ratios were significantly lower (1·28 versus 1·01, P

In a four-year old Australian Cattle Dog bitch, CT angiography of the communication of the azygos vein with the interrupted caudal vena cava, without portocaval shunting is described. The communication of the azygos vein with the discontinued caudal vena cava is usually an incidental finding which does not appear with portocaval shunting. CT angiography and 3D multiplanar reconstruction (MIP and VR) enable us to distinguish the processes regarding the direction and size of anomalies of the blood vessels. By means of imaging in two basic projections using the velocity ratio (VR) a significant enlargement and the communication of the caudal vena cava with a significantly enlarged azygos vein and its connection with the cranial vena cava is shown.

Adrenalectomy has been recognised as the treatment of choice for adrenal tumours. However, excision of large tumours with or without vena caval tumour thrombi is difficult. The purpose of this case series was to describe the use of 3D conformal hypofractionated radiotherapy for unresectable adrenal tumours (over 7 cm long) in three dogs (bulldog, shih tzu and miniature dachshund). The tumours had invaded the caudal vena cava in two of the dogs. The irradiation protocols included 23.7 Gy/three fractions/three weeks or 26 Gy/four fractions/four weeks. Following the treatment, tumours in two cases showed a 34 and 40 per cent reduction in size. No radiation-related adverse events were detected. Metastatic lesions developed in all cases. The overall survival in the three dogs was 19, 25 and 27 months. Therefore, 3D conformal hypofractionated radiotherapy can treat adrenal tumours without severe complications, and prolong the survival in dogs.

Simple summary Knowledge of physiological portal and hepatic blood flow in cattle is essential for the use of Doppler ultrasound for diagnostic purposes. In this paper, we describe a protocol for the systematic ultrasonography evaluation of the portal and hepatic system in cattle and report the reference values for healthy cows. Abstract In the past, hepatic blood flow in cows was invasively characterized to investigate different pathologies and physiological conditions. However, hepatic blood flow can be easily evaluated with transabdominal Doppler ultrasound. Sixteen healthy adult non-lactating, non-pregnant Holstein-Friesian cows were examined using B-mode and Doppler ultrasound between the right flank and 9th intercostal space to establish the best approach to the different parts of the portal and hepatic vein systems, and determine normal blood flow characteristics. The main portal vein was characterized by a turbulent, high-velocity flow due to the opposing confluence of the splenic and cranial mesenteric veins, while hepatic and caudal vena cava veins have laminar blood flow, in which the phasicity is considered mainly respiratory in origin. Reference values were determined in relation to the anatomical point of observation. In conclusion, transabdominal Doppler ultrasound of the portal system is a simple technique that allows non-invasive characterization of portal and hepatic blood haemodynamics in cows.

Veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis) are the most popular chameleons over the world, and consequently, two of the most frequent species presenting to veterinary practices. However, published studies on normal ultrasonographic anatomy for these lizards are currently lacking. The objectives of this prospective anatomic study were to develop an ultrasound protocol for evaluation of the coelomic cavity in these species and describe the normal ultrasonographic anatomy of the coelomic organs. Seventeen healthy veiled chameleons and 15 healthy panther chameleons were included. A linear 18 MHz transducer was used. Chameleons were sedated and restrained in right lateral recumbency by an assistant. Longitudinal and transverse images were acquired, and authors recorded qualitative and quantitative ultrasonographic characteristics of the coelomic structures. The kidneys, liver, caudal vena cava, hepatic veins, portal vein, gallbladder, wall of the stomach and intestine, gonads and, when distended, urinary bladder could be visualized during ultrasonography of the coelomic cavity in both species. The spleen, pancreas, and adrenal glands could not be identified. Findings from the current study supported the use of ultrasonography for veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis) with suspected intracoelomic diseases and provided normal reference information for future studies of these chameleon species.

An 8-year-old neutered female Yorkshire terrier with mediastinal neoplasm and subsequent cranial vena cava invasion developed multiple venous collaterals from the brachiocephalic venous trunks to the caudal vena cava. Collateral venous pathways have been described in dogs with obstruction or increased blood flow resistance of the caudal vena cava but cranial vena cava collaterals have not been reported until now in veterinary patients. In this report, the CTA characteristics of such peculiar vascular routes are described and compared to similar findings reported in human medical literature. The recognition of such ancillary CT finding could help radiologists to reach a more accurate diagnosis of superior vena cava syndrome.

Introduction/objectives In humans with impaired right-sided cardiac function, the caudal vena cava (CVC) diameter serves as a marker of venous congestion. This study aimed to investigate whether ultrasonographic CVC variables could identify the presence of right-sided congestive heart failure (R-CHF) in dogs with right-sided heart disease (RHD). Animals Fifty client-owned control dogs and 67 dogs with RHD were enrolled. The dogs with RHD were subdivided into the non-R-CHF (n = 43) and R-CHF (n = 24) groups. Materials and methods We measured and compared the ultrasonographic CVC variables and echocardiographic variables among the groups. Receiver operating characteristic (ROC) curve analysis was performed to calculate the sensitivity and specificity of the variables at optimal cutoff values. Results We obtained the highest accuracies of the ratio of the shortest diameter (SD) of the minimal CVC area to the aorta diameter (Ao) during inspiration [SD(min)/Ao] and of the ratio of SD(min) to the longest diameter of the minimal CVC area during inspiration [LD(min),SD/LD(min)], with high sensitivities, specificities, and an area under the ROC curve greater than 0.925. Conclusions In addition to the echocardiographic assessment of right-sided cardiac function, the CVC variables in this study, especially SD(min)/Ao and SD/LD(min), would be useful diagnostic indices for identifying R-CHF in dogs with RHD.

Necropsy examination of an adult neutered male cat, which was humanely destroyed as it had feline immunodeficiency virus (FIV) infection, demonstrated the presence of a left retrocaval ureter that was entrapped around the left limb of a double caudal vena cava. These associated anomalies originate from the complex embryofetal development of the caudal vena cava. Since no clinical signs had been reported and no gross lesions related to this anomaly were observed, this manifestation should be simply considered as an anatomical variation.

In thoracic radiographic examination, routinely used in cases which cardiac evaluation is indicated, quantitative assessment of the heart is a useful role to be used in combination with subjective analysis. Numerous studies about objective assessment of the cardiac size have been performed in several species, including sheep; however, there is scarce information regarding cardiac parameters of young Bergamasca sheep. Therefore, the purpose of this study was to determine the average results and suggest the range of expected normal values for parameters related to the heart size of young female Bergamasca sheep by radiographic evaluation. Fifteen healty 8 months-old female Bergamasca sheep (mean weight: 41.13±4.71kg) were submitted to right lateral recumbency thoracic radiography. The length of the fourth and third to fifth thoracic vertebrae, cardiac height and width, vertebral heart size, cardiophrenic contact, caudal vena cava height, aorta caliber and tracheal angle were measured and the mean results found were, respectively: 2.46±0.11cm (95% CI 2.41-2.52), 7.53±0.30cm (95% CI 7.38-7.68), 13.83±0.57cm, (95% CI 13.54-14.12), 8.99±0.37cm (8.80-9.17), 8.99±0.27 vertebrae (95% 8.85-9.13), 4.55±0.70cm (95% CI 4.19-4.90), 1.88±0.19cm (95% CI 1.79-1.97), 2.05±0.11cm (95% CI 2.00-2.11) and 14.36±2.73° (95% CI 12.98-15.75). Cardiac height and width and the sum of these parameters were compared to the length of third to fifth thoracic vertebrae, resulting in the respective mean values: 1.84±0.08 (95% IC 1.80-1.88), 1.20±0.05 (1.17-1.22) and 3.04±0.11 (95% IC 2.98-3.09). Ratios of cardiophrenic contact to cardiac height and caudal vena cava height to length of fourth thoracic vertebra were also evaluated and the mean values obtained were 0.33±0.05 (95% IC 0.30-0.35) and 0.76±0.08 (95% IC 0.72-0.81), respectively. Authors suggest that the values available in this study may be used as reference for normal heart size in young female Bergamasca sheep and as basis for further studies. RESUMO: No exame radiográfico torácico, rotineiramente utilizado em casos em que a avaliação cardíaca é indicada, a análise quantitativa do coração é um recurso útil a ser usado em combinação com a avaliação subjetiva. Diversos estudos relacionados à análise objetiva do tamanho cardíaco têm sido realizados em várias espécies, incluindo ovinos; no entanto, há pouca informação sobre os parâmetros cardíacos de ovinos jovens da raça Bergamácia. Dessa forma, o objetivo deste estudo foi determinar as médias e sugerir o intervalo de valores esperados para os parâmetros relacionados ao tamanho cardíaco de borregas Bergamácia por meio da avaliação radiográfica. Quinze borregas Bergamácia de 8 meses de idade (média de peso: 41,13±4,71kg) foram submetidas à radiografia torácica em decúbito lateral direito. O comprimento do quarto e da terceira a quinta vértebras torácicas, a altura e a largura cardíaca, o tamanho do coração em relação à unidade de vértebra torácica, o contato cardiofrênico, a altura da veia cava caudal, o calibre da aorta e o ângulo traqueal foram mensurados, sendo encontrados os seguintes valores médios, respectivamente: 2,46±0,11cm (95% IC 2,41-2,52), 7,53±0,30cm (95% IC 7,38-7,68), 13,83±0,57cm, (95% IC 13,54-14,12), 8,99±0,37cm (95% IC 8,80-9,17), 8,99±0,27 vértebras (95% IC 8,85-9,13), 4,55±0,70cm (95% IC 4,19-4,90), 1,88±0,19cm (95% IC 1,79-1,97), 2,05±0,11cm (95% IC 2,00-2,11) e 14,36±2,73° (95% IC 12,98-15,75). A altura e a largura cardíaca e a soma desses parâmetros foram comparados com o comprimento da terceira a quinta vértebras torácicas, resultando nos respectivos valores médios: 1,84±0,08 (95% IC 1,80-1,88), 1,20±0,05 (1,17-1,22) e 3,04±0,11 (95% IC 2,98-3,09). Também foram avaliadas as relações entre o contato cardiofrênico e a altura cardíaca e entre a altura da veia cava caudal e o comprimento da quarta vértebra torácica, sendo determinados os valores médios de 0,33±0,05 (95% IC 0,30-0,35) e 0,76±0,08 (95% IC 0,72-0,81), respectivamente. Os autores sugerem que os valores disponíveis no presente estudo podem ser utilizados como referência na avaliação das dimensões cardíacas de borregas Bergamácia e como base para estudos futuros.

A 5-year-old spayed female English Bulldog was evaluated for acute anorexia, lethargy, respiratory distress, and syncope. Contrast-enhanced computed tomography revealed the vascular malformation of azygous continuation of the caudal vena cava with extensive thrombus formation and pulmonary arterial thromboembolic disease. The patient was hospitalized for supportive treatment and was prescribed long-term clopidogrel therapy. The patient survived to discharge and at last follow-up remained clinically stable. While this vascular malformation has been reported in canines, to the authors' knowledge, this is the first reported case of pulmonary thromboembolic disease in a canine concurrent with this condition.

Background Intravascular volume assessment in foals is challenging. In humans, intravascular volume status is estimated by the caudal vena cava (CVC) collapsibility index (CVC-CI) defined as (CVC diameter at maximum expiration [CVCmax] – CVC diameter at minimal inspiration [CVCmin])/CVCmax × 100%. Hypothesis/Objectives To determine whether the CVC could be sonographically measured in healthy foals, determine differences in CVCmax and CVCmin, and calculate inter- and intrarater variability between 2 examiners. We hypothesized that the CVC could be measured sonographically at the subxiphoid view and that there would be a difference between CVCmax and CVCmin values. Animals Sixty privately owned foals

Objective To evaluate cardiovascular focused assessment with sonography for trauma and triage (CV-FAST) interobserver agreement for echocardiographic parameters and caudal vena cava (CVC) diameter measurement, between a cardiologist and 2 non-cardiologists after a 6-hour training course. Setting University veterinary teaching hospital. Animals Fifteen healthy Beagle dogs. Interventions None. Measurements and main results Echocardiography parameters were assessed via standardized views. Caudal vena cava was assessed via a subxiphoid window (CVC-SubX) using 3 measurements (minimal and maximal CVC diameter, and collapsibility index) and via a dorsolateral window (CVC-DL) using 1 measurement (CVC diameter). Bland-Altman analysis assessed agreement of each non-cardiologist with the cardiologist; coefficients of variation (CoV) quantified variability between observers. The 95% limits of agreement (LOA) and CoVs were considered acceptable for left atrial diameter, left atrium to aortic ratio, normalized left ventricle diameter in diastole and systole but non-acceptable for fractional shortening and pulmonary vein to pulmonary artery ratio. For CVC-SubX, the 95% LOA for maximum CVC diameter were acceptable, while minimum CVC diameter and CVC collapsibility index were non-acceptable. The CoVs were good for maximum and minimum CVC (7%) and poor for collapsibility index (37%). For CVC-DL, the 95% LOA were non-acceptable, although the CoV was considered good (11%). Conclusions A 6-hour training course in echocardiography allows non-cardiologists to assess left atrial diameter, left atrium to aortic ratio, normalized left ventricle diameter in diastole and systole, and CVCmax of the CV-FAST exam in healthy Beagles. Standardization of the CVC-SubX technique and assessment of the impact of the respiratory phase on CVC diameter in dogs is needed. Further studies are required to determine whether interobserver agreement remains acceptable when including different breeds. Assessment of basic echocardiographic parameters and the CVC to estimate volume status in small animal medicine merits further clinical evaluation.

Caudal vena cava duplication has been rarely reported in small animals. The purpose of this retrospective study was to describe characteristics of duplicated caudal vena cava in a large group of dogs. Computed tomography (CT) and ultrasound databases from two hospitals were searched for canine reports having the diagnosis "double caudal vena cava." One observer reviewed CT images for 71 dogs and two observers reviewed ultrasound images for 21 dogs. In all CT cases, the duplication comprised two vessels that were bilaterally symmetrical and approximately the same calibre (similar to Type I complete duplication in humans). In all ultrasound cases, the duplicated caudal vena cava appeared as a distinct vessel running on the left side of the abdominal segment of the descending aorta and extending from the left common iliac vein to the left renal vein. The prevalence of caudal vena cava duplication was 0.46% for canine ultrasound studies and 2.08% for canine CT studies performed at these hospitals. Median body weight for affected dogs was significantly lower than that of unaffected dogs (P < 0.0001). Breeds with increased risk for duplicated caudal vena cava were Yorkshire Terrier (odds ratio [OR] = 6.41), Poodle (OR = 7.46), West Highland White Terrier (OR = 6.33), and Maltese (OR = 3.87). Presence of a duplicated caudal vena cava was significantly associated with presence of extrahepatic portosystemic shunt(s) (P < 0.004). While uncommon in dogs, caudal vena cava duplication should be differentiated from other vascular anomalies when planning surgeries and for avoiding misdiagnoses.

Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector-row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases.

The aim of this study was to estimate echocardiographic elevated mean left atrium pressure (MLAP) based on measurements from thoracic radiographs and to determine a cut-off value for each radiographic measurement that suggests a high MLAP. A retrospective cross-sectional study was performed to include cases admitted from January 2015 to December 2016. Thoracic radiographic examinations from 93 dogs with and without a high MLAP were included. Specific measurements were made from thoracic radiographs and compared with echocardiographic variables known to indicate high MLAP. This comparison was used to generate equations that allowed the estimation of echocardiographic surrogates from the radiographic measurements. The values indicative of high MLAP were obtained using a regression curve. Formulas that indicated high MLAP were generated using a number of radiographic measurements. Positive echocardiographic findings of high MLAP were used as the gold standard. These formulas helped to predict high MLAP in myxomatous mitral valve disease (MMVD) without the need for echocardiographic examination. The best formula was left atrium (LA):aorta (Ao)echo = 0.03×(vertebral heart score,VHS) + 0.14×(LA) + 0.27×(LA:caudal vena cava (CVC)rad). Values ? 12.2v for VHS, ? 4.5cm for LA, ? 3.3 for LA:Aorad and ? 3.2 for LA:CVCrad suggested high MLAP. Thus, we propose equations, based on measurements from thoracic radiographs, to identify high MLAP. Simple radiographic thoracic measurements, such as LA:CVCrad, can be used to define overload and a high MLAP in dogs with MMVD.

Objective To describe an intercostal (IC) approach to the right adrenal (RA) gland in dogs. Study Design Cadaveric study and case series. Animals Dogs with right adrenal (RA) tumors (n = 11) and normal canine cadavers (6). Methods Cadavers had an IC (n = 3) or paracostal (3) approach to the RA. The relative spatial position of the RA to the incision was evaluated. Medical records (June 2007–December 2012) of dogs that had an IC approach to the RA were reviewed. Perioperative data were recorded and described. Results In cadavers, the RA was closer to the cranial aspect of the surgical incision after an IC approach compared with a paracostal approach. The IC approach for right adrenalectomy was successfully performed in 11 dogs (6 adrenocortical carcinomas, 4 pheochromocytomas, and 1 osteosarcoma) with a mean anesthesia duration of 242 minutes and mean surgical of 144 minutes. Dogs had vascular invasion into the phrenicoabdominal vein (n = 11) and caudal vena cava (6). There were no significant intra- or postoperative complications. One dog was euthanatized intraoperatively. Median survival time for all dogs was 786 days. Conclusions The IC approach for right adrenalectomy offers superior exposure of the RA compared with a paracostal approach.

Objective—To determine the prevalence of circumcaval ureters and other caudal vena cava variations in cats and determine whether circumcaval ureters were associated with macroscopic evidence of ureteral obstruction. Sample—301 domestic cat cadavers obtained from an animal shelter. Procedures—All cat cadavers were examined, and anatomic variations of the ureters and caudal vena cava were recorded. In cadavers with a circumcaval ureter, kidney length, width, and height were measured, and the ureters were examined macroscopically to determine whether there was gross evidence of ureteral obstruction in cats with circumcaval ureters. Results—At least 1 circumcaval ureter was present in 106 of the 301 (35.2%) cats, with a right circumcaval ureter identified in 92 (30.6%) cats, a left circumcaval ureter identified in 4 (1.3%), and bilateral circumcaval ureters identified in 10 (3.3%). Twenty-one (7.0%) cats had a double caudal vena cava, including 2 cats in which the double caudal vena cava was the only anatomic abnormality identified. No sex predilection for anatomic abnormalities was found. Mean right kidney length was significantly greater than mean left kidney length in cats with a right circumcaval ureter. Conclusions and Clinical Relevance—Circumcaval ureter was present in approximately a third of cats in this study. Variation in the development of the caudal vena cava is the proposed cause. The clinical relevance of this variation is unknown.

Background The vervet monkey (Chlorocebus sabaeus) is used commonly in cardiorespiratory biomedical research. This study was performed to establish reference values for thoracic structures and to describe the normal radiographic appearance of the vervet monkey thorax. Methods Right lateral and dorsoventral thoracic radiographs of ten mature vervet monkeys were evaluated. Anatomic structures were characterized using descriptive statistics. Results Normal measurements of skeletal, pulmonary, mediastinal, and cardiovascular structures are reported herein. Several ratios were calculated to assess the cardiac silhouette, caudal vena cava, and pulmonary arteries and veins. Conclusions Consistent measurements could be made on the majority of the thoracic structures evaluated. The aorta on lateral radiographs and the pulmonary veins on dorsoventral radiographs were obscured by a mild bronchointerstitial pattern and body conformation. Caudal vena cava-tapering was occasionally noted and attributed to general anesthesia. Species-specific thoracic radiographic reference values should prove useful in vervet monkey disease diagnosis and management.

Objective To report a technique for, and short-term outcome of unilateral laparoscopic adrenalectomy in dogs positioned in sternal recumbency without abdominal support. Study Design Experimental and prospective clinical study. Animals Healthy dogs (n = 5) and dogs with unilateral adrenal gland tumor (n = 9). Methods Anesthetized dogs were positioned in sternal recumbency with 2 cushions placed under the dog to elevate the chest and pelvic area so that the abdomen was not in contact with the surgical table allowing gravitational displacement of the abdominal viscera. Three 5-mm portals were located in the paralumbar fossa. Adrenal glands were carefully dissected and surrounding tissues sealed and cut using a vessel-sealing device. A retrieval bag or part of a surgical glove finger was used to remove the adrenal gland from the abdomen. Surgical time and complications were recorded, and short-term outcome assessed. Results Adrenal glands in normal dogs and unilateral adrenal tumors (8 left, 1 right) not involving the caudal vena cava in affected dogs were successfully removed laparoscopically. There were no major intraoperative complications. Of the dogs with adrenal tumors, 1 dog died within 24 hours of surgery from unrelated causes. Eight dogs recovered within 1 day and were discharged within 72 hours. Surgical times ranged from 42 to 117 minutes and were significantly shorter than those reported previously. Conclusions Positioning anesthetized dogs in sternal recumbency with the abdomen suspended to facilitate gravitational displacement of the abdominal viscera improves access to, and visibility of, the adrenal gland for laparoscopic removal.

We may imagine dolphins as continuous breath-holding divers or marathon swimmers that continuously exercise. However, just by admitting this simple comparison, we immediately come out with a number of questions that has been difficult to answer: What about the energy required to move uninterruptedly in and out of the water surface? What about the oxygen stores required to perform prolonged breath-hold dives? What about heartbeat or breathing frequency, diaphragm movements, and the effects of external pressure? Some of these complex aspects of diving physiology are still partially unsolved in dolphins, and are outside the scope of the present book.

A noninvasive method for quantifying hydration status would be helpful for clinical management and for research applications in dogs. This prospective, experimental, pilot study aimed to assess the feasibility of ultrasonographic measurement of the caudal vena cava to aorta ratio as a method for quantifying volume depletion in dogs. In 12 normal beagle dogs, furosemide was administered intravenously at a dose of 1 mg/kg, every 2 h, for 8 h, to induce consecutive volume depletion. Every 30 min after administration, ultrasonographic images of the caudal vena cava and aorta, and physical and biological parameters related to dehydration were acquired. On transverse and longitudinal planes of caudal vena cava and aorta images, the height and area of the caudal vena cava and aorta were measured to calculate the caudal vena cava/aorta ratios. All images were acquired by approaching from the right intercostal space with the dogs in left lateral recumbency. A negative correlation was present between the percentage of weight loss in dogs and all four investigated caudal vena cava/aorta ratios (transverse plane width of the caudal vena cava [TW]/aorta; transverse plane height of caudal vena cava [TH]/aorta; longitudinal plane area of the caudal vena cava [TA]/aorta; and longitudinal plane maximal height of the caudal vena cava [L]/aorta). Significant differences (P

Adrenalectomy is the treatment of choice for adrenal tumors that are producing adverse clinical signs. Surgical planning prior to adrenalectomy is aided by identifying tumors with invasion into adjacent vessels or the presence of a tumor thrombus extending into the caudal vena cava. In this paper, we evaluated the sensitivity and specificity of ultrasound in determining if vascular invasion or tumor thrombus is present. Thirty-four dogs with 36 adrenal tumors were reviewed retrospectively. Overall, 36% of tumors had vascular invasion. Abdominal ultrasound was 100% sensitive and 96% specific in identifying the presence of a tumor thrombus in the caudal vena cava. The sensitivity and specificity was 76% and 96%, respectively, when all forms of vascular invasion were evaluated and included patients with vascular wall invasion without concurrent thrombus. Abdominal ultrasound is a good screening tool for identifying vascular invasion or tumor thrombus associated with adrenal tumors in dogs.

The venous drainage from reproductive organs of rats is described; new data on peculiarities of the venous drainage are obtained. Objects of study were adult Wistar white rats (20 animals). The animals have passed precision dissection of vessels in order to study anatomic peculiarities of venous drainage from the left spermary in male rats and internal genital organs in female rats in norm. It has been shown that the venous drainage from the left spermary follows the spermatic vein entering into the pampiniform plexus system, which continues into the single venous trunk, which, in its turn, divides into the ascending and descending veins. The descending vein runs into the common left iliac vein, while the ascending vein runs into the renal vein. The venous drainage from female reproductive organs follows through the uterine vein, which, taking the tubal and spermatic veins, runs from the left into the left renal vein and from the right into the caudal vena cava.

The objective of this study was to investigate the relationship between hepatic triacylglycerol content (TAG) and hepatic size and shape assessed by transcutaneous ultrasonography in dairy cows. In a second part, the usefulness of ultrasonographic measurements pertaining to the size and shape of the liver for the diagnosis of fatty liver was evaluated. Transcutaneous ultrasonographic examination of the liver was carried out in 133 German Holstein cows (BW: 578 ± 6 kg; age: 5 ± 0.2 yr; withers height: 145 ± 0.3 cm). The size of the liver, angle of the ventral liver margin, and thickness of the liver over the portal vein and caudal vena cava were measured in the 10th and 11th intercostal spaces via ultrasonography. As the gold standard, TAG was determined enzymatically in liver biopsies. Hepatic TAG ranged from 5 to 292 mg/g of liver fresh weight (FW). Cows were allocated to 4 groups according to their hepatic TAG content (TAG ≥150 mg/g of FW, n = 32; ≥100 to 150 mg/g of FW, n = 34; ≥50 to 100 mg/g of FW, n = 38