Focused Cardiac Ultrasonography in Cats

The Pathological and Histopathological Findings in Cats with Clinically Recognised Hypertrophic Cardiomyopathy Are Related to the Severity of Clinical Signs and Disease Duration

Hypertrophic cardiomyopathy (HCM) is the most frequent type of cardiac disease in cats. Due to its high prevalence and risk of sudden and severe signs, the disease is an important topic of various research. Despite the focus on the clinical course of the disease, studies presenting the pathological and histopathological patterns are rare. The study was conducted as a retrospective analysis of feline patients subjected to postmortem examination in the Cardiopathology Unit due to a clinical diagnosis of hypertrophic cardiomyopathy based on echocardiographic examination and ACVIM guidelines. Thirty-four cats clinically diagnosed with HCM were enrolled in the study. During the postmortem examination, hearts were subjected to gross morphometric and histopathological evaluation. Our results show that the histopathological pattern in cats with clinically stated HCM is very diverse, affecting both ventricles and atria. The histopathological picture is more complex in animals diagnosed earlier and treated for a longer period. Moreover, it is generally unrelated to wall thickness, with only left ventricular fibrosis affecting the thickness of the left ventricular wall. In conclusion, further research combining clinical and pathological results is required to unambiguously determine the histopathological remodelling that takes place in the myocardium of cats with hypertrophic cardiomyopathy.

Feline caudal vena cava to aorta ratio reference interval

OBJECTIVES

The primary objective of this investigation was to ultrasonographically evaluate the caudal vena cava to aorta (CVC:Ao) ratio in healthy, conscious cats and to generate reference intervals. A secondary objective was to identify the site of examination with the least intra- and inter-observer variability. This investigation was undertaken to assess whether the CVC:Ao ratio holds promise as a technique to assess intravascular volume responsiveness in cats.

METHODS

In total, 42 healthy cats were included for reference interval generation. Ultrasound examinations were performed by two operators with each examination performed twice by each operator on the same occasion. Examinations were performed on conscious cats in left lateral recumbency. Ultrasound sites investigated were the subxiphoid, hepatic intercostal, hepatorenal and iliac bifurcation. Operators also assessed each site for 'ease of visualisation' on a scale of 0-3.

RESULTS

Reference intervals were generated for the CVC:Ao ratio at all four ultrasonographic sites. While each site demonstrated low variability around its mean ratio, all sites exhibited significant intra- and inter-observer variability. The hepatorenal and iliac bifurcation sites were found to be the easiest to visualise (score 3; well-defined visualisation of both vessels) and had reference intervals of 0.8-1.41 and 0.75-1.2, respectively.

CONCLUSIONS AND RELEVANCE

The ultrasonographic assessment of the CVC:Ao ratio was possible at four anatomical locations in the cat. The hepatorenal and iliac bifurcation may offer more readily assessable CVC:Ao ratios. Further studies are necessary to assess the utility of the CVC:Ao ratio in disease states, including in hypovolaemia and hypervolaemia.

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.

Utility of focused cardiac ultrasonography training in veterinary students to differentiate stages of subclinical myxomatous mitral valve disease in dogs

BACKGROUND

Differentiation of the subclinical phases of myxomatous mitral valve disease (MMVD) in dogs relies heavily on echocardiography. Focused cardiac ultrasonography (FCU) is a point-of-care technique that can assess heart size.

HYPOTHESIS/OBJECTIVES

Veterinary students trained in FCU can differentiate dogs with subclinical MMVD based on left ventricular (LV) and left atrial (LA) dimensions.

ANIMALS

Forty-eight dogs with subclinical MMVD.

METHODS

Veterinary students were trained to measure LV dimension and LA-to-aortic root dimension ratio (LA : Ao) using FCU. Dogs were categorized into 2 cohorts based on whether or not the LV normalized internal diastolic dimension was ≥1.7 and LA : Ao was ≥1.6. Agreement between FCU and echocardiographic studies performed by cardiologists was evaluated.

RESULTS

One-hundred and forty-six FCU examinations were performed by 58 veterinary students on 48 dogs. Overall agreement between students and cardiologists was moderate (Fleiss' kappa, 0.54; 95% confidence interval [CI], 0.39-0.69; P < .001). Percentage accuracy in observations with heart dimensions less than the cutoffs (86/89, 97%) was significantly higher than in observations in with larger hearts (31/57, 54%; P < .001). Agreement increased from moderate to good as heart sizes became more extreme. Degree of confidence by students in performing FCU was significantly higher at the end vs start of the study.

CONCLUSIONS AND CLINICAL IMPORTANCE

Categorization of dogs with subclinical MMVD by veterinary students using FCU was associated with moderate to good agreement with echocardiography. Focused cardiac ultrasonography is a point-of-care method that can help assess clinical stage in dogs with subclinical MMVD.