Incidence of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy surgery at a surgical specialty clinic: 182 cases (2017-2021)

The objectives of this study were to evaluate the risk and predictive factors of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy at a surgical specialty clinic. Medical records, hematologic results, surgical reports, and histopathologic results from 182 dogs that underwent splenectomy for the treatment of splenic masses or nodules were reviewed retrospectively. The majority of dogs (57.7%) had benign splenic diagnoses with no malignancy. Hemangiosarcoma was diagnosed in 32.4% of the dogs. A final multivariable model indicated that thrombocytopenia, anemia, and a smaller diameter of the largest splenic nodule were risk factors for hemangiosarcoma (P<0.001), and hemoperitoneum (P = 0.01) was an additional risk factor when nodule diameter was not evaluated. There were 91 dogs that had hemoperitoneum, and 60.4% of those dogs had malignant splenic lesions. Of the 33 dogs that underwent a splenectomy for incidentally identified splenic lesions, 93.9% had benign splenic lesions. Breed size was not a significant predictor of splenic malignancy risk; however, all 6 of the German shepherds included in the study had a hemangiosarcoma diagnosis. Overall prevalence of splenic malignancy including HSA may be overestimated in some canine populations.

Evaluation of clopidogrel, hypercoagulability, and platelet count in dogs undergoing splenectomy for splenic masses

Dogs that had splenectomy are predisposed to fatal thrombotic conditions, and thrombocytosis is a risk factor for post-splenectomy hypercoagulability. However, in veterinary medicine, there are no specific therapeutic approaches for managing this hypercoagulability. This study aimed to determine the preventive effect of clopidogrel on post-operative hypercoagulability during the first 2 weeks post-splenectomy in dogs with splenic masses. This study included 12 dogs that had splenectomy. Seven dogs received no treatment (group A), and five were treated with clopidogrel (group B). Clopidogrel was loaded at 10 mg/kg on day 2 and continued at 2 mg/kg until day 14. Blood samples were collected on the day of surgery and 2, 7, and 14 days after splenectomy in both groups. In group B, thromboelastography (TEG) was performed on the same days. In group A, there was significant elevation of platelet counts on days 7 (p = 0.007) and 14 (p = 0.001) compared to day 0. In group B, the platelet counts were significantly elevated on day 7 (p = 0.032) but no significant difference was found on day 14 compared to day 0. Platelet counts on day 14 were significantly higher in group A than in group B (p = 0.03). The lower platelet counts were correlated with alterations in TEG parameters, and no significant differences were found in the K and α-angle values at all postoperative assessment points compared to day 0. Our study suggests that clopidogrel may reduce post-operative thrombocytosis and hypercoagulability in dogs that undergo splenectomy for splenic masses.

Use of human intravenous immunoglobulin for the treatment of 12 dogs with newly diagnosed malignant disease and presumed secondary immune-mediated thrombocytopenia

OBJECTIVES

To evaluate the safety and efficacy of human intravenous immunoglobulin in dogs with newly diagnosed malignancy and presumed secondary immune-mediated thrombocytopenia.

MATERIALS AND METHODS

Twelve client-owned dogs with newly diagnosed malignant disease and presumed secondary immune-mediated thrombocytopenia were prospectively enrolled to receive a single infusion of human intravenous immunoglobulin at a dose of 0.5 to 1 mg/kg intravenous over 8 hours. A complete treatment response was defined as a platelet estimation of ≥40,000 platelets/μL within 24 hours and a partial response within 48 hours from the completion of human intravenous immunoglobulin infusion. No treatment response was defined as a platelet estimation remaining <40,000 platelets/μL over 48 hours from the completion of the human intravenous immunoglobulin infusion. This pilot study had a prospective, open-label, uncontrolled design.

RESULTS

Out of the 12 enrolled dogs, seven completed the study. A complete treatment response to human intravenous immunoglobulin was identified in one lymphoma dog and a partial response was noted in another lymphoma dog. The remaining 10 dogs had no response to human intravenous immunoglobulin. No clinically relevant adverse reactions to human intravenous immunoglobulin occurred in any of the 12 initially enrolled dogs during the infusion and over a 3-month follow-up period for the seven surviving dogs.

CLINICAL SIGNIFICANCE

The results of this study suggest that the use of human intravenous immunoglobulin in dogs with newly diagnosed malignant disease and presumed secondary immune-mediated thrombocytopenia appears safe, but not effective for the treatment of thrombocytopenia. Larger multi-centre, prospective, double-blinded, placebo-controlled, outcome-based, malignancy-specific studies are needed to further evaluate these preliminary findings.

Splenic stromal sarcomas in dogs: Outcome and clinicopathological prognostic factors in 32 cases

Due to the low frequency and the changes in diagnostic techniques and terminology during the last few years, only little clinical information is available on splenic stromal sarcoma (SSS). This multi-institutional study aimed at gathering clinical cases of SSS in dogs and investigates their clinical behaviour, as well as analyse possible clinicopathological prognostic factors, including the use of adjuvant therapy. Dogs with a histologically confirmed SSS that underwent splenectomy were retrospectively included. To be included in the study, either FFPE tissue blocks or multiple tissue sections had to be available for histopathologic and immunohistochemical revision. Clinical and pathological variables, along with adjuvant therapy data, were collected. Cumulative incidence of metastatic disease was analysed through univariate and bivariate analyses. The impact of adjuvant chemotherapy on metastasis incidence and survival was assessed, considering an estimated propensity score. A total of 32 dogs were included. Among them, 22 developed metastases with an incidence of 37.5%, 59.38%, and 65.94% at 6, 12, and 24 months, respectively. Univariate analysis identified mitotic count, total scoring, and necrosis as prognostic factors. In bivariate analysis, mitotic count remained prognostic. The administration of adjuvant chemotherapy did not have an impact on metastasis incidence or survival time. The study found that dogs with SSSs are at high risk of metastasis, although a small subgroup may experience longer survival after splenectomy. Mitotic count was the only variable having a reliable prognostic impact. Adjuvant chemotherapy did not appear to decrease the incidence of metastasis or prolong survival in these dogs.

Evaluation of thrombin generation in dogs administered clopidogrel

Introduction

The antiplatelet effect of clopidogrel can vary between patients. A modified thromboelastography (TEG) protocol (TEG-Platelet Mapping assay® [TEG-PM]) can be used for clopidogrel monitoring but is not widely available. Thrombin generation (TG) assays could offer a novel alternative. The main objective of this pilot study was to assess TG assay variables (lag time, peak, endogenous thrombin potential [ETP]) in dogs before and after 7 days of clopidogrel administration and compare with TEG-PM variables (maximum amplitude [MA]-ADP and percentage (%) inhibition).

Methods

Six healthy mix-breed dogs were enrolled in this pilot study. Blood samples for platelet count, TG assays, and TEG-PM were obtained at two time points, corresponding to baseline, and after 7 days of clopidogrel administration (mean 2.3 +/- 0.3 mg/kg PO q24 hours). Data were then compared with a Student's t-test.

Results

There was no significant change in TG assay variables performed on platelet poor plasma after 7 days of clopidogrel administration: lag time (Day 1: 1.8 +/- 0.2 min, Day 7: 1.8 +/- 0.2 min, p = 0.42); peak (Day 1: 76 +/- 7 nM, Day 7: 72 +/- 10 nM, p = 0.49); and ETP (Day 1: 399 +/- 27 nM*min, Day 7: 392 +/- 32 nM*min; p = 0.49). There were significant changes in TEG MA-ADP (Day 1: 19 +/- 8 mm, Day 7: 9 +/- 6 mm, p = 0.04) and % inhibition (Day 1: 58 +/- 27, Day 7: 99 +/- 0.3, p = 0.02).

Discussion

Clopidogrel administration did not lead to changes in TG assay variables performed on platelet poor plasma samples, despite concomitant changes in TEG-PM variables consistent with platelet inhibition. Based on this pilot study, thrombin generation performed on platelet poor plasma may not be a useful antiplatelet monitoring tool in dogs.

Retrospective evaluation of surgical site infection after open splenectomies with and without perioperative prophylactic antibiotic coverage

OBJECTIVES

Perioperative prophylactic antibiotics (PPA) are widely used in veterinary medicine to prevent surgical site infections (SSI). Current guidelines advocate the use in clean procedures only if surgeries exceed 90 minutes, or in patients with an ASA score ≥3. Procedure specific recommendations are currently lacking. The following study aimed to analyze the protective effect of PPA in dogs undergoing open splenectomy.

METHODS

The electronic database of our institution was searched for dogs that underwent splenectomy between 10/2017 and 01/2023. Data collection included age at presentation, breed, weight, reason for splenectomy, diagnosis, ASA class, PPA regime, surgery time, anesthesia time, lowest blood oxygen concentration during anesthesia, lowest body temperature, and lowest blood pressure during surgery as well as duration of hospitalization. Dogs were included if a follow-up of 30 days after surgery was available, or if death occurred within this timeframe.

RESULTS

A total of 112 dogs were included. Of these, 46 dogs received PPA, and 66 did not. Most dogs were classified ASA 3 or higher (PPA 87%, non-PPA 80.3%). One SSI (1.5% SSI rate) occurred in the non-PPA group (overall SSI rate 0.9%). Due to the low SSI rate, statistical analysis of risk factors for SSI development was not possible.

CONCLUSION

The described infection rate of 1.5% without PPA indicates, that splenectomy does not qualify as high-risk surgery for SSI, even in patients with ASA class 3 or higher.

CLINICAL RELEVANCE

As splenectomies are frequently performed, the findings of the current study could have a major impact on the overall antimicrobial burden in routine veterinary practice.

Evaluation of the validity of the double two-thirds rule for diagnosing hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass: a systematic review

OBJECTIVE

To evaluate the validity of the double two-thirds rule for a diagnosis of splenic hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass.

SAMPLE

Systematic literature review.

PROCEDURES

3 databases (PubMed, CAB abstracts, and World of Science) were searched in November 2020. Articles were included if data on dogs with nontraumatic hemoperitoneum due to a splenic mass were included and subsequent pathologic diagnosis could be determined.

RESULTS

In total, 2,390 unique articles were identified, with 66 articles meeting the criteria for full-text review and 14 articles included for analysis. A total of 1,150 dogs were evaluated, with 73.0% (840/1,150) of dogs being diagnosed with a malignant splenic lesion and 27.0% (310/1,150) being diagnosed with a benign splenic lesion. Of the malignancies, 87.3% (733/840) were hemangiosarcoma. Levels of evidence were low, and bias was high as most included studies were retrospective case series.

CLINICAL RELEVANCE

The double two-thirds rule should be refined when evaluating dogs with nontraumatic hemoperitoneum from a ruptured splenic mass, with more dogs being diagnosed with a malignancy and hemangiosarcoma specifically than the double two-thirds rule indicates. These findings may be useful in an emergency setting to guide owners on potential diagnoses for dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass. However, there remains a portion of these dogs with benign conditions and nonhemangiosarcoma malignancies that may have a good long-term prognosis compared to dogs with hemangiosarcoma. Studies with higher levels of evidence, lower risks of bias, and large case numbers are needed in the literature.

[A multifactorial risk index for evaluation of anesthetic risk in dogs: the LeiV-Risk-Index]

OBJECTIVE

The Leipzig Veterinary Risk-Index - "LeiV-Risk-Index" is a multifactorial risk index developed to enable an improved objective assessment of the anesthetic risk in dogs. The scoring system is based on 10 risk factors affecting perioperative mortality. The aim of this study was to evaluate the applicability of the LeiV-Risk-Index and its risk factors as well as to perform a direct comparison with the ASA-classification.

MATERIAL AND METHODS

An online survey was conducted among veterinarians working in small animal medicine throughout Germany. Participants received a questionnaire containing information on 15 selected patients. They were asked to classify the patients according to the LeiV-Risk-Index and ASA-classification and to answer several questions concerning their professional background. The results were statistically analyzed considering the consistency among veterinarians of rating the different patients by using Fleiss'-Kappa. The correlation of LeiV-Risk-Index and ASA-classification was calculated.

RESULTS

The consistency of all assigned LeiV-risk classes between participants was moderate (κ = 0.55) and higher than classification by ASA (κ = 0.33). On average, 3 different LeiV-risk classes and 4 different ASA-classes were assigned for one patient. There was a positive correlation between LeiV-risk class and increasing ASA-class. No effect of gender or clinical experience of the veterinarian could be demonstrated on ranking patients. There was also no effect of how confident veterinarians felt in applying the LeiV-Risk-Index.

CONCLUSION UND CLINICAL RELEVANCE

The LeiV-Risk-Index is the first index available in veterinary medicine for assessing anesthetic risk that is based on objective risk criteria and whose objectivity exceeds that of the ASA classification. Anesthetic patients can thus be evaluated more consistently in veterinary medicine as well. Utility and practicability were positively received by 95 % of the participants. Further revision of individual risk criteria needs to be reconsidered.

Treatment and outcomes of two pigs treated for hemoabdomen secondary to splenic disease

OBJECTIVE

To report the management and outcomes of two pigs undergoing emergency surgery for hemoabdomen secondary to splenic disease.

STUDY DESIGN

Case report.

ANIMAL

Two adult pigs with hemoabdomen and suspected splenic pathology.

METHODS

Pigs were admitted for several clinical signs including lethargy, inappetence, vomiting, abdominal distention, hypothermia, and tachycardia. Abdominal ultrasound and abdominocentesis led to a diagnosis of hemoabdomen secondary to splenic disease.

RESULTS

The spleen was confirmed as the source of hemorrhage during midline exploratory celiotomy in both pigs. Splenic rupture resulted from splenic vein thrombosis in one pig and splenic torsion in the other. Complications included intraoperative hemorrhage and intraabdominal adhesion formation. Four years following splenectomy, one pig was euthanized because of widespread small intestinal adhesions causing luminal obstruction, while the other pig was euthanized following a diagnosis of chronic myeloid leukemia.

CONCLUSIONS

A ventral midline celiotomy provided adequate exposure for splenectomy. The procedure allowed resolution of signs in both pigs. Splenic pathology, such as vessel thrombosis or torsion, may result in splenic rupture and should be considered as a differential in pigs with hemoabdomen.

Complications and outcomes associated with laparoscopic-assisted splenectomy in dogs

OBJECTIVE

To report the perioperative characteristics and outcomes of dogs undergoing laparoscopic-assisted splenectomy (LAS).

ANIMALS

136 client-owned dogs.

PROCEDURES

Multicentric retrospective study. Medical records of dogs undergoing LAS for treatment of naturally occurring splenic disease from January 1, 2014, to July 31, 2020, were reviewed. History, signalment, physical examination and preoperative diagnostic test results, procedural information, complications, duration of hospitalization, histopathologic diagnosis, and perioperative outcomes were recorded. Perioperative complications were defined using the Veterinary Cooperative Oncology Group - Common Terminology Criteria for Adverse Events (VCOG-CTCAE v2) guidelines.

RESULTS

LAS was performed for treatment of a splenic mass (124/136 [91%]), immune-mediated disease (7/136 [5%]), splenomegaly (4/136 [3%]), or immune-mediated disease in conjunction with a splenic mass (1/136 [1%]). Median splenic mass size was 1.3 cm3/kg body weight. Conversion to open laparotomy occurred in 5.9% (8/136) of dogs. Complications occurred in 78 dogs, with all being grade 2 or lower. Median surgical time was 47 minutes, and median postoperative hospital stay was 28 hours. All but 1 dog survived to discharge, the exception being postoperative death due to a suspected portal vein thrombus.

CLINICAL RELEVANCE

In the dogs of this report, LAS was associated with low rates of major complications, morbidity, and mortality when performed for a variety of splenic pathologies. Minimally invasive surgeons can consider the LAS technique to perform total splenectomy in dogs without hemoabdomen and with spleens with modest-sized splenic masses up to 55.2 cm3/kg, with minimal rates of complications, morbidity, and mortality.

Pre-operative Hemostatic Status in Dogs Undergoing Splenectomy for Splenic Masses

Portal system thrombosis is a rare but potentially fatal complication of splenectomy in dogs. The mechanism behind development of post-operative portal system thrombosis is unclear but may include alterations of portal blood flow following surgery, acquired hypercoagulability and endothelial dysfunction. The aim of the study was to evaluate hemostatic biomarkers in hemodynamically stable (heart rate <130 beats/min, blood lactate < 2.5 mMol/L) and non-anemic (hematocrit >35%) dogs prior to splenectomy for splenic masses. Our hypothesis was that this population of stable dogs would have pre-existing laboratory evidence of hypercoagulability unrelated to shock, bleeding, anemia, or other pre-operative comorbidities. Pre-operatively, abdominal ultrasonography was performed and blood was collected for platelet enumeration, prothrombin time (PT), activated partial thromboplastin time (aPTT), kaolin-activated thromboelastography (TEG), fibrinogen, von Willebrand factor activity (vWF:Ag), antithrombin and thrombin-antithrombin complex (TAT). Histopathological diagnosis and 30-day survival were recorded. None of the 15 enrolled dogs had pre-operative sonographic evidence of portal system thrombosis. Three of fifteen dogs were thrombocytopenic, three had thrombocytosis, three were hyperfibrinogenemic, one had low vWF:Ag, three had mild prolongations of PT and none had abnormal aPTT. Based on the TEG G value, 13/15 dogs were hypercoagulable (mean ± SD 13.5 ± 5.4 kd/s). Antithrombin deficiency was identified in 9/15 dogs (mean ± SD 68.7 ± 22.7%) with 5/9 having concurrently elevated TAT suggesting active thrombin generation. No dogs developed portal system thrombosis and all achieved 30-day survival. Pre-operative hypercoagulability was recognized commonly but its association with post-operative thrombosis remains undetermined.

Epidemiology and Survival of Dogs Diagnosed with Splenic Lymphoid Hyperplasia, Complex Hyperplasia, Stromal Sarcoma and Histiocytic Sarcoma

Canine splenic fibrohistiocytic nodules traditionally encompassed benign lymphoid hyperplasia, complex hyperplasia, and malignant fibrous histiocytoma. The latter has been recently re-classified into histiocytic sarcoma and stromal sarcoma. Reliable indicators of post-splenectomy survival and demographic factors predisposing to the four types of nodules are not completely understood. This study aims to estimate frequency, survival times, and identify risk factors of splenectomized dogs diagnosed with lymphoid hyperplasia, complex hyperplasia, histiocytic sarcoma, and stromal sarcoma using medical records containing histopathological diagnosis from the VetCompass Australia database (1989−2018), which collects demographic, and clinical information from veterinary clinics. Out of 693 dogs, 315 were diagnosed with fibrohistiocytic nodules, mostly lymphoid hyperplasia (169/693, 24.4%), followed by stromal sarcoma (59/693, 8.5%), complex hyperplasia (55/693, 7.9%), and histiocytic sarcoma (32/693, 4.6%). Dogs aged 8−10 years were more likely to be diagnosed with histiocytic or stromal sarcoma than lymphoid hyperplasia. Dogs diagnosed with lymphoid hyperplasia had a longer survival time than those with other diagnoses (median > 2 years). Dogs diagnosed with histiocytic sarcoma had longer survival times (median 349 days) than stromal sarcoma (median 166 days). Results suggest that knowledge of the type of splenic fibrohistiocytic nodule, patients’ age, and sex can be used to increase prognostic accuracy.

Development of perioperative premature ventricular contractions as an indicator of splenic hemangiosarcoma and median survival times

OBJECTIVE

The objectives of this study are (1) to determine whether there is an association between dogs with splenic hemangiosarcoma (HSA) and the development of premature ventricular contractions (VPCs), (2) to determine if there is a higher likelihood for dogs with ruptured splenic masses to be diagnosed with HSA and to develop VPCs, (3) to determine if the development of VPCs affects median survival times compared to dogs with benign or non-HSA malignant splenic masses.

STUDY DESIGN

Retrospective case series.

ANIMALS

Forty-five dogs.

METHODS

Medical records of dogs undergoing splenectomy were reviewed for signalment, perioperative electrocardiogram (ECG), hematological values, histologic diagnosis, metastasis, and survival times. ECGs were performed preoperatively, intraoperatively, and continuously postoperatively. The presence of VPCs was recorded. The data were evaluated for an association between the development of VPCs and the histologic diagnosis of HSA.

RESULTS

Eighteen out of 45 (40%) dogs were diagnosed with HSA with 13/18 (72%) dogs having VPCs postoperatively (P = .02). Ruptured splenic HSA and VPCs were noted in 13 dogs (P = .73). An association between dogs with and without VPCs diagnosed with HSA and median survival times could not be established.

CONCLUSION

Postoperative VPCs were more likely with splenic HSA. Splenic masses were more likely to be HSA if ruptured but less likely to develop VPCs. Development of VPCs does not affect median survival times.

CLINICAL SIGNIFICANCE

Development of postoperative VPCs may be a potential indicator of HSA, however, this warrants further investigations. Development of VPCs does not have a deleterious effect on survival.

Retrospective evaluation of thrombocytopenia and tumor stage as prognostic indicators in dogs with splenic hemangiosarcoma

OBJECTIVE

To identify physical examination and perioperative CBC variables in dogs with splenic hemangiosarcoma (HSA) that could aid in predicting progression-free interval (PFI) and overall survival time (OST) in affected dogs.

ANIMALS

70 client-owned dogs with splenic HSA treated with splenectomy and chemotherapy between September 2004 and October 2016.

PROCEDURES

A retrospective search of the University of Minnesota Veterinary Medical Center medical records database was performed to identify dogs with splenic HSA treated with splenectomy and with evidence in the medical records of intent to treat with chemotherapy. Data collection included dog signalment and body surface area, results from CBCs performed within 6 days before to 2 days after splenectomy, whether dogs had hemoabdomen or received transfusions, and tumor stage. Hematocrit, WBC count, and platelet count were treated as categorical variables (divided into terciles: above, within, or below reference limits) because of variation among reference intervals for the numerous analyzers used. Associations between variables and PFI or OST were investigated with Cox regression analyses, and hazard ratios (HRs) for a shorter PFI or OST were reported. Population Pearson correlation coefficient (ρ) analysis was performed to identify potential associations between variables of interest.

RESULTS

Stage 3 HSA was identified as a negative prognostic indicator of PFI (HR, 6.6) and OST (HR, 4.5). Perioperative thrombocytopenia was similarly associated with shorter PFI (HR, 2.2) and OST (HR, 2.0). Results for Hct correlated (ρ = 0.58) with those for platelet count, and although our findings did not indicate a notable association between anemia and shorter PFI, such could not be ruled out.

CONCLUSIONS AND CLINICAL RELEVANCE

The prognostic value of thrombocytopenia warrants further substantiation to understand causal and mechanistic connections, and the presence of thrombocytopenia ultimately may prove valuable in guiding treatment recommendations for dogs with splenic HSA.

Evaluation of point-of-care coagulation tests as alternatives to anti-Xa activity for monitoring the anticoagulant effects of rivaroxaban in healthy dogs

OBJECTIVE

To evaluate a panel of coagulation assays for their potential utility in rivaroxaban monitoring as alternatives to the rivaroxaban-specific anti-Xa activity (RIVA).

DESIGN

Prospective experimental study.

SETTING

University research laboratory.

ANIMALS

Five healthy neutered male Beagles.

INTERVENTIONS

Dogs were administered a median dose of 1.8 mg/kg rivaroxaban (range, 1.6-1.8 mg/kg) orally once daily for 2 consecutive days as part of a pharmacodynamic study. Blood was collected from a preplaced jugular catheter at time points relative to their rivaroxaban administration (0, 2, 4, 8, 24, 36, and 48 h) for measurement of RIVA, prothrombin time (PT), activated partial thromboplastin time, RapidTEG, and thrombin generation variables.

MEASUREMENTS AND MAIN RESULTS

One hundred forty data points were available for analysis. There was poor correlation between RIVA and RapidTEG variables: R time (R) (min) (r = 0.554, P < 0.0001), K time (K) (min) (r = -0.204, P = 0.016), alpha angle (degrees) (r = 0.152, P = 0.073), Maximum amplitude (MA) (mm) (r = 0.106, P = 0.215), and G value (G) (dynes/s) (r = 0.108, P = 0.205). A good correlation was noted between thrombin generation variables and RIVA: lag time (min) (r = 0.827, P < 0.0001), peak (nM) (r = -0.752, P < 0.0001), and endogenous thrombin potential (nM·min) (r = -0.762, P < 0.0001). There was an excellent correlation between PT and RIVA (r = 0.915, P < 0.0001) and a good correlation between activated partial thromboplastin time and RIVA (r = 0.772, P < 0 .0001).

CONCLUSIONS

Of all the coagulation tests investigated, the PT correlated best with RIVA. There is potential for PT being a convenient second-line monitoring option in dogs receiving rivaroxaban, but further work is necessary to validate other PT assays. Thromboelastography performed with strong activators correlated poorly with anti-Xa activity.

The influence of feeding and gastroprotectant medications on the Factor Xa inhibitory activity of orally administered rivaroxaban in normal dogs

OBJECTIVE

Rivaroxaban is a new anticoagulant option for dogs, yet its reported oral bioavailability is as low as 60%. The objective of this study was to examine the influence of feeding and gastroprotectant medications on the bioactivity (anti-Xa activity) of rivaroxaban in healthy dogs.

DESIGN

Prospective experimental study.

SETTING

University research laboratory.

ANIMALS

Five healthy neutered male purpose-bred Beagles.

INTERVENTIONS

Dogs were administered a median dose of 1.8 mg/kg rivaroxaban (range, 1.6-1.8 mg/kg) orally once daily for 2 consecutive days with either (1) no food, (2) food, (3) sucralfate 30 minutes before rivaroxaban, or (4) omeprazole at the same time as rivaroxaban. Blood was collected from preplaced jugular catheters immediately before and at 6 time points after rivaroxaban administration (2, 4, 8, 24, 36, and 48 hours). A rivaroxaban calibrated anti-Xa activity assay (RIVA) was used to monitor anticoagulant effect.

MEASUREMENTS AND MAIN RESULTS

Rivaroxaban administration resulted in significant increases in RIVA (P = 0.02), with peak activities occurring 2 to 4 hours after dosingduring each study arm. No feeding was associated with significantly higher RIVA at the 36-hour time point compared to all other treatment arms (P < 0.0001), and feeding resulted in high RIVA at the 48-hour time point compared with sucralfate administration (P = 0.003). No significant changes in RIVA were otherwise identified with respect to feeding or gastroprotectant administration (P = 0.2).

CONCLUSIONS AND CLINICAL IMPORTANCE

Although administration without food demonstrated an apparent increase in RIVA 36 hours after drug administration, clinically relevant differences among treatment groups were not identified in combined analyses of time points. Based on these results, dogs treated with rivaroxaban do not require special modification of feeding practices or gastroprotectant drug administration.

Partial Gastrectomy at the Time of Splenectomy in Two Dogs With Splenic Neoplasia and Gastric Involvement

Splenic malignancies are reported in 30%-76% of dogs presenting with splenic masses, and splenectomy is the cornerstone in their management. However, long term prognosis is guarded due to the high rates of distant metastases reported both for HSA and nonangiogenic nonlymphomatous sarcomas. Metastases from splenic tumors usually occur to regional lymph nodes, liver, omentum, and lungs. These case series aim to describe 2 cases of splenic neoplasia with gastric involvement and report the surgical technique and outcomes associated with the condition. Two mixed-breed dogs were referred for a splenic mass and underwent explorative celiotomy. In both cases, the splenic mass was firmly attached to the gastric wall, and splenectomy with concurrent partial gastrectomy was thus performed. In case 1, liver lobectomy due to a hepatic mass was also performed. In case 2, the regional nodes were also excised due to lymphoadenomegaly. Both dogs recovered uneventfully from surgery and were discharged from the hospital at 72 and 96 hours. Histopathological examination was costent with splenic undifferentiated sarcoma and hepatic adenocarcinoma in one dog. The other dog had a diagnosis of malignant fibrous histiocytoma with nodal metastases. Neoplastic invasion of the stomach was histologically confirmed in both dogs. Adjuvant chemotherapy was refused, and both dogs were euthanized due to tumor progression at 71 and 58 days, respectively. According to our results, splenectomy with concurrent gastrectomy is feasible in dogs with splenic tumours involving the gastric wall. However, long term prognosis is poor, as previously reported for metastatic splenic sarcomas.

Postoperative thrombocytosis and thromboelastographic evidence of hypercoagulability in dogs undergoing splenectomy for splenic masses

OBJECTIVE

To determine the frequency and severity of thrombocytosis and thromboelastographic evidence of hypercoagulability during the first 2 weeks after splenectomy in dogs with splenic masses and to investigate relationships between platelet counts and thromboelastography values.

ANIMALS

34 dogs undergoing splenectomy for splenic masses.

PROCEDURES

Blood samples for platelet counts and thromboelastography were obtained at induction of anesthesia (day 0) prior to splenectomy and on days 2, 7, and 14.

RESULTS

Mean platelet counts were 167.9 × 10³/μL, 260.4 × 10³ μ/L, 715.9 × 10³/μL, and 582.2 × 10³/μL on days 0, 2, 7, and 14, respectively, and were significantly higher at all postoperative assessment points than on day 0. Thrombocytosis was observed in 3% (1/34), 6% (2/33), 81% (21/26), and 69% (18/26) of dogs on days 0, 2, 7, and 14. Platelet counts > 1,000 × 10³/μL were observed in 1 dog on day 2 and in 5 dogs on day 7. One or more thromboelastography values suggestive of hypercoagulability were observed in 45% (15/33), 84% (26/31), 89% (24/27), and 84% (21/25) of dogs on days 0, 2, 7, and 14. At each assessment point, higher platelet counts were correlated with thromboelastography values suggestive of hypercoagulability.

CONCLUSIONS AND CLINICAL RELEVANCE

Marked thrombocytosis and thromboelastography values suggestive of hypercoagulability were common during the first 2 weeks after splenectomy for the dogs of this study. If present, hypercoagulability could increase the risk for development of postsplenectomy thrombotic conditions such as portal system thrombosis and pulmonary thromboembolism.

Outcomes of 43 small breed dogs treated for splenic hemangiosarcoma

OBJECTIVE

To determine outcome and prognostic factors in small breed dogs in which hemangiosarcoma was diagnosed and whether outcomes differed between small and large breed dogs with splenic hemangiosarcoma.

STUDY DESIGN

Bi-institutional retrospective study.

ANIMALS

Forty-three small breed (<20 kg) and 94 large breed client-owned dogs.

METHODS

Medical records were reviewed to identify dogs treated with splenectomy for splenic hemangiosarcoma. Data acquired included signalment, preoperative staging, bloodwork results, surgical findings, histopathologic findings, administration of chemotherapy, presence/absence of metastatic disease, and survival time (ST). Cox proportional hazards regression analysis was performed to assess prognostic factors associated with survival.

RESULTS

The overall median ST was 116 days and 97 days for small and large breed dogs, respectively. The ST for dogs treated with surgery and chemotherapy was 207 and 139 days for small and large breed dogs, respectively. The disease-free interval (DFI) was 446 and 80 days for small and large breed dogs, respectively. Dog size was associated with DFI (P = .02) but not with ST (P = .09). The presence of metastasis at diagnosis was associated with decreased ST in small (P = .03) and large (P = .0009) breed dogs. Administration of chemotherapy (P = .02) was associated with increased ST (P = .02) in small breed dogs.

CONCLUSION

The ST was not different in small and large breed dogs with splenic hemangiosarcoma treated with splenectomy and chemotherapy.

CLINICAL SIGNIFICANCE

Prognosis remains poor despite aggressive therapies in small and large breed dogs.

Prospective observational study of dogs with splenic mass rupture suggests potentially lower risk of malignancy and more favourable perioperative outcomes

Haemoperitoneum secondary to ruptured splenic tumours can be either benign or malignant in origin. The majority of previous studies of canine haemoperitoneum have been retrospective, which are associated with well-recognized biases, such as the potential to underappreciate the diversity of outcomes in a complex presentation such as haemoperitoneum. This study seeks to prospectively define perioperative morbidity and mortality of haemoperitoneum in dogs secondary to ruptured splenic masses. Forty dogs with haemoperitoneum secondary to a ruptured splenic mass met the inclusion criteria. As expected, the cohort predominately consisted of older large breed dogs. All dogs underwent preoperative staging and had a splenectomy performed. Histopathologic analysis was performed on the splenic mass, as well as any possible metastatic lesions that were noted intra-operatively. Perioperative care outside of splenectomy was delivered in specialty practices using current conventional approaches to care (eg, transfusions and anti-arrhythmic medications). Fifteen dogs (37.5%) had benign splenic tumours and were cured with surgery alone, whereas 62.5% had malignant disease (most often haemangiosarcoma [HSA]). Surgical outcomes were highly favourable in the vast majority of dogs. Indeed, 38 dogs (95%) survived and were discharged after a median hospitalization of 39.5 hours. Independent predictors of longer hospitalization times included receiving a transfusion and the development of an arrhythmia. Although small, this cohort defines distinctive and optimistic perspectives for dogs with haemoperitoneum from splenic tumour rupture. These favourable outcomes from this prospective study are sufficient to ask if larger prospective studies should be conducted to better inform owners during this challenging cancer emergency presentation.

Influence of use of a bipolar vessel sealing device on short-term postoperative mortality after splenectomy: 203 dogs (2005-2018)

OBJECTIVE

To compare short-term postoperative mortality in dogs after splenectomy performed with or without a bipolar vessel sealing device (BVSD) and to identify variables associated with mortality.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Client-owned dogs (n = 203).

METHODS

Medical records of dogs that underwent splenectomy from 2005-2018 were reviewed. Mortality rates were compared between dogs that underwent splenectomy with or without BVSD. Causes of death and variables associated with short-term mortality were assessed.

RESULTS

Fifteen of 203 (7.4%) dogs died prior to discharge, and seven (3.4%) dogs died prior to suture removal for a total short-term mortality rate of 22 of 203 (10.8%). The estimated difference in proportion of deaths prior to discharge between the BVSD and non-BVSD groups was -0.01 (95% confidence interval = -0.08 to 0.06). Duration of anesthesia was longer when splenectomy was performed without BVSD (median 168 vs 152 minutes; P = .03). Multivariate analysis identified intraoperative (odds ratio [OR] 5.7) or postoperative (OR 13.6) administration of blood products, increasing duration of anesthesia (OR 1.15 per additional 16 minutes), and intraoperative ventricular arrhythmias (OR 6.8) as significantly associated with death prior to discharge. Intraoperative (OR 3.2) or postoperative (OR 7.7) administration of blood products was associated with death prior to suture removal.

CONCLUSION

Use of a BVSD did not appear to increase short-term mortality after splenectomy.

CLINICAL SIGNIFICANCE

Dogs undergoing splenectomy that require intraoperative or postoperative transfusions, experience intraoperative ventricular arrhythmias, or have prolonged anesthesia may be at risk for death in the short-term postoperative period.

Evaluation of cytological diagnostic accuracy for canine splenic neoplasms: An investigation in 78 cases using STARD guidelines

Cytology represents a useful diagnostic tool in the preliminary clinical approach to canine splenic lesions, and may prevent unnecessary splenectomy. However, few studies have evaluated diagnostic accuracy of cytology in the diagnosis of canine splenic neoplasms. The aim of this study was to determine overall accuracy, sensitivity, specificity, positive and negative predictive values (i.e. diagnostic accuracy indexes) of cytology for canine splenic neoplasms following Standards for the Reporting of Diagnostic Accuracy Studies (STARD) guidelines. A consecutive series of canine splenic cytological samples was retrospectively retrieved from the database of the Diagnostic Pathology Service of the Department of Veterinary Medicine (DIMEVET—University of Milan). Histopathology was set as the diagnostic reference standard. Cytological cases were enrolled when slides were available for review and when the same lesion was submitted for histopathology. Seventy-eight (78) lesions were included in the study. By histopathology, 56 were neoplastic and 22 were non-neoplastic. Cytology had an overall accuracy of 73.08% (95% C.I. 61.84%-82.50%), sensitivity of 64.29% (95% C.I. 50.36%-76.64%), specificity of 95.45% (95% C.I. 77.16%-99.88%), and positive and negative predictive values of 97.3% (95% C.I. 84.01%-99.60%) and 51.22% (95% C.I. 42.21%-60.15%), respectively. Low sensitivity and negative predictive value were balanced by very high specificity and positive predictive value. When positive for neoplasia, cytology represents a useful diagnostic tool to rule in splenic neoplasia, prompting surgery independently from other diagnostic tests. Conversely, a negative cytological result requires additional investigations to confirm the dog to be disease free.

Histiocytic Sarcoma and Hemangiosarcoma Update

Histiocytic sarcoma (HS) and hemangiosarcoma (HSA) are uncommon and aggressive neoplasms that develop much more frequently in dogs than in cats. Breed-specific predispositions have been identified for both cancers. The development of novel diagnostics is underway and may aid in earlier diagnosis. Therapeutic approaches to HS and HSA depend on the stage of disease and may include surgery, radiation therapy, and chemotherapy. Such interventions improve outcome; however, aside from a small number of clinical circumstances, both diseases are considered largely incurable. Continued efforts toward the identification of driver mutations and subsequent druggable targets may lead to improvements in long-term prognosis.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 1-Defining populations at risk

OBJECTIVES

Thrombosis is a well-recognized phenomenon in dogs and cats with a significant impact on morbidity and mortality. Despite growing awareness of thrombosis and increased use of antithrombotic therapy, there is little information in the veterinary literature to guide the use of anticoagulant and antiplatelet medications. The goal of Domain 1 was to explore the association between disease and thrombosis in a number of conditions identified as potential risk factors in the current veterinary literature, to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. Revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated included immune-mediated hemolytic anemia, protein-losing nephropathy, pancreatitis, glucocorticoid therapy, hyperadrenocorticism, neoplasia, sepsis, cerebrovascular disease, and cardiac disease.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Of the diseases evaluated, a high risk for thrombosis was defined as dogs with immune-mediated hemolytic anemia or protein-losing nephropathy, cats with cardiomyopathy and associated risk factors, or dogs/cats with >1 disease or risk factor for thrombosis. Low or moderate risk for thrombosis was defined as dogs or cats with a single risk factor or disease, or dogs or cats with known risk factor conditions that are likely to resolve in days to weeks following treatment.

CONCLUSIONS

Documented disease associations with thrombosis provide the basis for recommendations on prescribing provided in subsequent domains. Numerous knowledge gaps were identified that represent opportunities for future study.

Clinical application of the American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines to small animal cases

OBJECTIVE

To illustrate the application of the Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines to the management of dogs and cats at risk of developing thrombosis using a case-based approach.

ETIOLOGY

Dogs and cats become at risk of developing thrombosis from a wide range of conditions. These conditions often involve a specific insult followed by an inflammatory response and when combined with other contributing factors (eg, hypercoagulability, vascular endothelial injury, hemodynamic changes) create favorable conditions for thrombosis.

DIAGNOSIS

Development of thrombosis in small animals remains challenging to demonstrate. Compatible clinical signs, the presence of known risk factors, and supporting diagnostic tests may be highly suggestive of the development of thrombosis.

THERAPY

Therapeutic recommendations in accordance with the CURATIVE guidelines for dogs and cats are described in specific case vignettes presented. Discussion is centered on antithrombotic drug choices and dosing protocols, as outlined in Domains 2 and 3 of the CURATIVE guidelines. Where appropriate, guidelines related to therapeutic monitoring (Domain 4) and discontinuation of antithrombotics (Domain 5) were included.

PROGNOSIS

In small animals at risk of developing thrombosis, overall prognosis may be improved by following consensus-based recommendations on the use of antithrombotics as outlined in the CURATIVE guidelines. Whether such interventions have any impact on outcome requires further investigation.

Presurgical assessment of splenic tumors in dogs: a retrospective study of 57 cases (2012-2017)

The purpose of this study was to evaluate the clinical and imaging characteristics of canine splenic tumors and to establish guidelines for the presurgical assessment of splenic tumors in dogs. Fifty-seven dogs that underwent total splenectomy for the treatment of splenic tumors were evaluated by examining medical records, hematologic results, diagnostic imaging results, and histopathologic results. The maximum lesion size from ultrasonography was significantly different between malignant and benign tumors (p = 0.002). There was a correlation between tumor margination and type of splenic tumors (p = 0.045). Precontrast lesion attenuation on computed tomography was significantly different between splenic malignant and benign tumors (p = 0.001). The mean ± SD precontrast lesion attenuation of malignant tumors was 40.3 ± 5.9 Hounsfield units (HU), and for benign tumors, it was 52.8 ± 6.8 HU. In conclusion, some variables of the imaging examination could be used to distinguish the type of splenic tumor. Based on the study results, using a diagnostic flowchart would be effective in increasing the survival rate of patients with splenic malignant tumors. In addition, fine needle aspiration or magnetic resonance imaging prior to surgical exploration and histopathologic examination may be useful in achieving a more accurate diagnosis.

Survival time of dogs with splenic hemangiosarcoma treated by splenectomy with or without adjuvant chemotherapy: 208 cases (2001-2012)

OBJECTIVE

To determine survival time for dogs with splenic hemangiosarcoma treated with splenectomy alone, identify potential prognostic factors, and evaluate the efficacy of adjuvant chemotherapy.

DESIGN

Retrospective case series.

ANIMALS

208 dogs.

PROCEDURES

Medical records were reviewed, long-term follow-up information was obtained, and survival data were analyzed statistically.

RESULTS

154 dogs were treated with surgery alone, and 54 were treated with surgery and chemotherapy. Twenty-eight dogs received conventional chemotherapy, 13 received cyclophosphamide-based metronomic chemotherapy, and 13 received both conventional and metronomic chemotherapy. Median survival time of dogs treated with splenectomy alone was 1.6 months. Clinical stage was the only prognostic factor significantly associated with survival time. When the entire follow-up period was considered, there was no significant difference in survival time between dogs treated with surgery alone and dogs treated with surgery and chemotherapy. However, during the first 4 months of follow-up, after adjusting for the effects of clinical stage, survival time was significantly prolonged among dogs receiving any type of chemotherapy (hazard ratio, 0.6) and among dogs receiving both conventional and metronomic chemotherapy (hazard ratio, 0.4).

CONCLUSIONS AND CLINICAL RELEVANCE

Clinical stage was strongly associated with prognosis for dogs with splenic hemangiosarcoma. Chemotherapy was effective in prolonging survival time during the early portion of the follow-up period. Combinations of doxorubicin-based conventional protocols and cyclophosphamide-based metronomic protocols appeared to be more effective than either type of chemotherapy alone, but prolongations in survival time resulting from current protocols were modest.

Perioperative Monitoring of Heart Rate and Rhythm

Perioperative disorders of heart rate and rhythm are common and can contribute to patient morbidity and mortality. Management of perioperative arrhythmias is facilitated by understanding the basic mechanisms of arrhythmia formation and the role of transient imbalances. The decisions of when and how to treat perioperative arrhythmias are based on whether or not hemodynamic signs are present and the assumed risk of sudden arrhythmic death. Perioperative arrhythmias warrant careful monitoring and consideration of potential complications associated with antiarrhythmic therapy.