Comparison of computed tomography pulmonary angiography and point‐of‐care tests for pulmonary thromboembolism diagnosis in dogs

Abstract

ObjectivesTo evaluate the feasibility of CT pulmonary angiography for identification of naturally occurring pulmonary thromboembolism in dogs using predefined diagnostic criteria and to assess the ability of echocardiography, cardiac troponins, D-dimers and kaolin-activated thromboelastography to predict the presence of pulmonary thromboembolism in dogs.MethodsTwelve dogs with immune-mediated haemolytic anaemia and evidence of respiratory distress were prospectively evaluated. Dogs were sedated immediately before CT pulmonary angiography using intravenous butorphanol. Spiral CT pulmonary angiography was performed with a 16 detector-row CT scanner using a pressure injector to infuse contrast media through peripheral intravenous catheters. Pulmonary thromboembolism was diagnosed using predefined criteria. Contemporaneous tests included echocardiography, arterial blood gas analysis, kaolin-activated thromboelastography, D-dimers and cardiac troponins.ResultsBased on predefined criteria, four dogs were classified as pulmonary thromboembolism positive, three dogs were suspected to have pulmonary thromboembolism and the remaining five dogs had negative scans. The four dogs identified with pulmonary thromboembolism all had discrete filling defects in main or lobar pulmonary arteries. None of the contemporaneous tests was discriminant for pulmonary thromboembolism diagnosis, although the small sample size was limiting.Clinical SignificanceCT pulmonary angiography can be successfully performed in dogs under sedation, even in at-risk patients with respiratory distress and can both confirm and rule out pulmonary thromboembolism in dogs.

Retrospective evaluation of pimobendan and sildenafil therapy for severe pulmonary hypertension due to lung disease and hypoxia in 28 dogs (2007-2013)

“…Although D‐dimers were assessed in three dogs, their use for diagnosing PTE are not without limits as values may peak at 2 h post thromboembolic before declining in the subsequent 24 h (Goggs et al . ). Even if elevated D‐dimer values are identified in an animal, more recent studies (Epstein et al .…”

“…; Goggs et al . ) have shown a poor correlation between increased D‐dimer concentrations and PTE. A recent study found that thoracic computed tomography appears more sensitive than D‐dimer testing for the detection of PTE (Goggs et al .…”

“…A recent study found that thoracic computed tomography appears more sensitive than D‐dimer testing for the detection of PTE (Goggs et al . ), however, was not available at the authors’ institution at the time of this study. The diagnostic value of D‐dimers for dogs with severe PH remains unclear at this time.…”

ACVIM consensus statement guidelines for the diagnosis, classification, treatment, and monitoring of pulmonary hypertension in dogs

“…Dogs with a condition associated with acute or chronic PE/PT/PTE are at risk for PH. Examples include immune‐mediated hemolytic anemia, spontaneous hyperadrenocorticism, protein‐losing nephropathy, protein‐losing enteropathy, sepsis, neoplasia, and disseminated intravascular coagulation . Additionally, although heartworm disease and angiostrongylosis cause PH by multifactorial mechanisms, an important contributor to increased PAP is parasitic embolism.…”

Abnormal platelet activity in dogs and cats – impact and measurement

“…Although these signs may be marked, it can still be difficult to document an underlying thrombus and advanced imaging may be required (Goggs et al . ).…”