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

Resolution of Exercise-Induced Syncope After Stenting of the Azygos Vein in a Dog with Segmental Aplasia and Azygos Continuation of the Levopositioned Caudal Vena Cava

A 1-year-old Maltese-Poodle mixed breed dog was referred to the cardiology service because of severe exercise intolerance and daily exercise-induced syncopal episodes. Physical examination revealed no abnormalities. Echocardiography showed intermittent underfilling of the heart. Abdominal ultrasound examination revealed a segmental aplasia of the caudal vena cava between the kidneys and the liver, and azygos continuation of the cava. The azygos vein dorsal to the right kidney showed a severe aneurysm with stasis of blood. Computed tomographic angiography showed that the right crus of the diaphragm was probably responsible for the intermittent compression of the dilated azygos vein, which was thought to have subsequently led to insufficient venous return to the heart. The underfilled ventricles could not produce sufficient cardiac output, which caused the assumed cerebral hypoperfusion due to presumed systemic arterial hypotension. Under general anesthesia a self-expanding nitinol stent was implanted into the azygos vein at the level of the diaphragm. All clinical signs resolved immediately after surgery. The dog remained free from clinical signs (6 months after surgery). This is the first report that describes the successful treatment of this congenital vascular anomaly. Ultrasonography of the caudal vena cava should be performed in dogs with unexplained syncope.

Viscoelastic coagulation monitoring parameters in cats with acute arterial thromboembolism

BACKGROUND

Hypercoagulability has been documented in cats with cardiac disease. However, hemostatic parameters, including viscoelastic coagulation monitoring (VCM) have not been reported in cats with arterial thromboembolism (ATE).

HYPOTHESIS/OBJECTIVES

Compare VCM parameters in cats with acute cardiogenic ATE and in control cats.

ANIMALS

Sixteen cats with ATE and 30 control cats.

METHODS

Multicenter university-based prospective study. Cardiogenic ATE was diagnosed based on physical examination and by ultrasonographically-diagnosed left atrial enlargement. Viscoelastic coagulation monitor analysis, CBC, serum biochemistry profile and coagulation profile were performed at admission in cats with ATE. Analysis from healthy control cats was performed using blood collected by direct venipuncture. Our objective was comparison of VCM parameters clot time (CT), clot formation time (CFT), alpha angle (Angle), maximum clot formation (MCF), amplitude at 10 and 20 minutes (A10 and A20, respectively) and clot lysis index at 30 and 45 minutes (LI30 and LI45, respectively) between ATE and control cats.

RESULTS

Cats with ATE had a decreased angle compared to control cats, with a median (range) of 43° (30-48°) compared to 47° (14-59°; P = .01). The parameters A10, A20 and MCF were decreased in ATE cats compared to control cats with a median (range) of 19 units (8-32) compared to 22 units (6-38), 24.5 units (11-40) compared to 29 units (10-47) and 29.5 units (13-44) compared to 33.5 units (14-53), respectively (P = .01, .01 and .01, respectively). The parameters CT, CFT, LI30 and LI45 were similar between groups (P = .22, .09, .62 and .34, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Cats with cardiogenic ATE cats have VCM parameters consistent with hypocoagulability compared with healthy cats.

Feline Aortic Thromboembolism: Recent advances and future prospects

PRACTICAL RELEVANCE

Feline aortic thromboembolism (FATE) is commonly encountered in clinical medicine, especially in emergency situations. This often devastating syndrome usually develops secondarily to severe heart disease, and has short- and long-term consequences.

CLINICAL FEATURES

The clinical presentation of FATE is consistent with peripheral ischemic neuropathy, usually in both pelvic limbs. Diagnosis is relatively straightforward, but can be assisted with Doppler ultrasound, point-of-care ultrasound or infrared thermal imaging.

RECENT ADVANCES AND FUTURE PROSPECTS

Interpretation of survival rates in cats with FATE has been hampered by historically high admission euthanasia, but recent studies suggest a survival rate with supportive care of 30-40%. Moreover, with advances in post-FATE thromboprophylaxis, median survival times of over 1 year are being achieved. Future directions include use of thrombolytic agents and treatment of common FATE sequelae such as acute kidney injury and reperfusion injury.

OUTLINE

This article, aimed at small animal veterinarians, including emergency practitioners, reviews key aspects of the clinical presentation, diagnosis and treatment options for FATE, with a view to guiding client and veterinarian decision-making. Three case studies are included to illustrate the practical application of information presented in the review.

EVIDENCE BASE

There are limited prospective studies on FATE, although the recent literature reflects a resurgence in clinical research interest in the past few years. Advances in FATE treatment will benefit many cats and it is important that research efforts continue to identify appropriate treatment modalities.

Pulmonary Thromboembolism and Myocarditis Resulting from a Large Pacing-Lead-Associated Right Ventricular Thrombus in a Dog with Chronic Cough as Presenting Sign

In the present case report, we describe the clinical course and postmortem findings of a 12-year-old Labrador retriever dog with a third-degree atrio-ventricular block that developed a chronic cough, and later dyspnea and weakness as a result of massive pulmonary thromboembolism 3 years after implantation of a transvenous permanent pacemaker. A large soft tissue mass was seen in the right ventricular chamber around the pacing lead with echocardiography. Initially, this was thought to be caused by mural bacterial endocarditis based on hyperthermia, severe leukocytosis and the appearance of runs of ventricular tachycardia, the latter suggesting myocardial damage. While blood culture results were pending, antibiotics were administered without a positive effect. Due to clinical deterioration, the owner elected for euthanasia and a post-mortem examination confirmed a right ventricular thrombus and surrounding myocarditis, without signs of bacterial infection, and a massive pulmonary thromboembolism. We conclude that pulmonary thromboembolism should be considered in dogs with a cough that have an endocardial pacing lead implanted. Serial screening for proteinuria before and after implantation of an endocardial pacing lead would allow timely initiation of prophylactic antiplatelet therapy. Local myocarditis can develop secondary to an intracavitary thrombus, which can subsequently lead to runs of ventricular tachycardia.

Bilateral lysis of aortic saddle thrombus with early tissue plasminogen activator (BLASTT): a prospective, randomized, placebo-controlled study in feline acute aortic thromboembolism

OBJECTIVES

The aim of this study was to investigate the impact of tissue plasminogen activator (TPA) on the treatment of feline aortic thromboembolism (FATE).

METHODS

Cats diagnosed with FATE involving ⩾2 limbs were enrolled in a prospective, multicenter, double-blinded, randomized, placebo-controlled study within 6 h of an event. Diagnosis was made by clinical findings and one confirmatory criterion. Cats received placebo or TPA (1 mg/kg/h with the first 10% by bolus). All cats received pain control and thromboprophylaxis. The primary outcome was a change from baseline in a published limb score at 48 h. Secondary outcomes included 48 h survival, survival to discharge and complication proportions. Statistical analyses included pattern-mixture models, logistic regression and Fisher's exact, Student's t- and Mann-Whitney-Wilcoxon tests.

RESULTS

Based on a power analysis, 40 cats were enrolled; however, only 20 survived to 48 h (TPA, n = 12; placebo, n = 8 [P = 0.34]). There was a statistically significant improvement in limb scores compared with baseline for both groups (P <0.001). Limb score at 48 h was 1 point lower (better) in the TPA group (P = 0.19). Thrombolysis had no statistically significant effect on 48 h survival (P = 0.22). Lower affected limb lactate was associated with better 48 h survival (odds ratio 1.53, 95% confidence interval 1.08-2.17; P = 0.02). The survival to discharge rates were 45% (TPA) and 30% (placebo; P = 0.51). Complications in the TPA and placebo groups included acute kidney injury (22% and 19%, respectively; P = 1.00) and/or reperfusion injuries (33% and 19%, respectively; P = 0.45).

CONCLUSIONS AND RELEVANCE

Survival and complication rates of acute FATE were not different with or without thrombolysis. High in-hospital mortality decreased the statistical power to detect a statistically significant difference between treatments with regard to our primary outcome.

Outcome and treatments of dogs with aortic thrombosis: 100 cases (1997-2014)

Background

Aortic thrombosis (ATh) is an uncommon condition in dogs, with limited understanding of risks factors, outcomes, and treatments.

Objectives/Hypothesis

To describe potential risk factors, outcome, and treatments in dogs with ATh.

Animals

Client‐owned dogs with a diagnosis of ATh based on ultrasonographic or gross necropsy examination.

Method

Multicentric retrospective study from 2 academic institutions.

Results

One hundred dogs were identified. Anti‐thrombin diagnosis, 35/100 dogs were nonambulatory. The dogs were classified as acute (n = 27), chronic (n = 72), or unknown (n = 1). Fifty‐four dogs had at least one comorbidity thought to predispose to ATh, and 23 others had multiple comorbidities. The remaining 23 dogs with no obvious comorbidities were classified as cryptogenic. Concurrent illnesses potentially related to the development of ATh included protein‐losing nephropathy (PLN) (n = 32), neoplasia (n = 22), exogenous corticosteroid administration (n = 16), endocrine disease (n = 13), and infection (n = 9). Dogs with PLN had lower antithrombin activity than those without PLN (64% and 82%, respectively) (P = .04). Sixty‐five dogs were hospitalized with 41 subsequently discharged. Sixteen were treated as outpatient and 19 euthanized at admission. In‐hospital treatments varied, but included thrombolytics (n = 12), alone or in combination with thrombectomy (n = 9). Fifty‐seven dogs survived to discharge. Sixteen were alive at 180 days. Using regression analysis, ambulation status at the time of presentation was significantly correlated with survival‐to‐discharge (P < .001).

Conclusions/Clinical Importance

Dogs with ATh have a poor prognosis, with nonambulatory dogs at the time of presentation having worse outcome. Although the presence of comorbid conditions associated with hypercoagulability is common, an underlying cause for ATh was not always identified.

Clinical, clinicopathologic, and gastrointestinal changes from aspirin, prednisone, or combination treatment in healthy research dogs: A double-blind randomized trial

Background

Dogs with immune‐mediated disease are often coadministered glucocorticoids and aspirin, but ulcerogenic effects of current protocols are unknown.

Objectives

To compare gastrointestinal changes among dogs administered aspirin, prednisone, and combination treatment.

Animals

Twenty‐four healthy research dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial of dogs administered placebo, aspirin (2 mg/kg q24h), prednisone (2 mg/kg q24h), or combination treatment PO for 28 days. Clinical signs were recorded daily, with laboratory work performed at baseline and day 28. Gastrointestinal mucosal hemorrhages, erosions, and ulcers were numerated for endoscopic studies performed on days 0, 14, and 28; endoscopic mucosal lesion scores were calculated. Results were compared using mixed model repeated‐measures analyses of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.

Results

Gastric mucosal lesion scores differed by treatment‐by‐time (F[6, 40] = 4.4, P = .002), treatment (F[3, 20] = 7.1, P = .002), and time (F[2, 40] = 18.9, P < .001). Post hoc analysis revealed increased scores in the aspirin (day 14 only), prednisone, and prednisone/aspirin groups during treatment. Ulcers were identified on 14 studies, representing 10 dogs. Dogs receiving prednisone and prednisone/aspirin had 11.1 times (95% CI, 1.7‐73.6) and 31.5 times (95% CI, 3.5‐288.0) higher odds, respectively, of having endoscopic mucosal lesion scores ≥4 than dogs receiving placebo (P ≤ .01).

Conclusions and Clinical Importance

Gastrointestinal bleeding occurs commonly in dogs administered aspirin, prednisone, or prednisone/aspirin treatment, with higher lesion scores for dogs receiving combination treatment. Even severe lesions are not accompanied by clinical signs.