Abdominal Sonographic Evaluation: In the Field, at the Hospital, and After Surgery.

Abdominal sonography is currently a routine procedure in the evaluation of colic in the horse. This imaging technique is used in both the assessment of the horse presented in the emergency setting with acute colic and the assessment of the horse presented for chronic or recurrent colic in the nonemergency setting. Sonography for colic evaluation is used by specialists in different disciplines and by general practitioners in the ambulatory and hospital settings. In this review, we will focus on indications and clinical interpretation of findings as well as recent developments in abdominal sonography.

Suspensory ligament size does not change after plantar fasciotomy and neurectomy of the deep branch of the lateral plantar nerve by ultrasonographic assessment.

OBJECTIVE: To determine the short-term effect of plantar fasciotomy and neurectomy (PFN) of the deep branch of the lateral plantar nerve on the proximal suspensory ligament (PSL) cross-sectional area (CSA) in horses with hindlimb proximal suspensory desmopathy (PSD). STUDY DESIGN: Analytical, observational, cohort study. SAMPLE POPULATION: Twenty-one horses. METHODS: Records of horses with chronic PSD treated by PFN were included if a preoperative ultrasonographic examination was available and at least one postoperative ultrasonographic examination. One masked observer measured the ultrasonographic cross-sectional area (CSA) of the PSL. Intraobserver reliability was determined by repeatedly measuring a subset of ultrasonographic images (n = 127). Two masked observers measured the cross-sectional area of the proximal suspensory ligament (PSL-CSA) on preoperative proton density (PD)-weighted transverse high field magnetic resonance images (n = 19 horses) . Agreements for PSL-CSA between preoperative ultrasonographic and MRI measures and between the two magnetic resonance imaging (MRI) observers were assessed. Follow up considered the horses' ability to return to exercise and their owners' satisfaction. RESULTS: The reliability of the ultrasonographic measurement of the PSL-CSA was excellent. Agreement between ultrasonographic assessment and MRI assessment of PSL-CSA was good. No difference was detected between preoperative (median, interquartile range; oblique-incidence, 2.07, 1.72-2.55; on-incidence, 2.23, 1.98-2.65) and postoperative (oblique-incidence, 2.08, 1.80-2.74; on-incidence, 2.28, 2.01-2.74) PSL-CSAs. At a median of 12 months (4-33 months), 16/20 (80%) owners reported the horse was "better" and 15/20 (75%) functioned at or above preoperative levels. CONCLUSION: Ultrasonographic measurement of the PSL-CSA was reproducible and in good agreement with MRI measurement. The PSL-CSA was not influenced by PFN. CLINICAL SIGNIFICANCE: The PSL-CSA cannot be used to guide return to function.

Ex vivo comparison of ultrasonographic intestinal wall layering with histology in horses: A feasibilty study.

Ultrasonography is increasingly being used as a clinical and research method for evaluating the gastrointestinal tract in horses, however published studies comparing ultrasonographic and histologic characteristics of equine intestinal wall layers are currently lacking. Objectives of this prospective, observational, methods comparison, case series study were to compare the layering pattern and thickness of the intestinal wall layers determined using ex vivo and in vivo ultrasonography with those determined using histology. For the ex vivo study, twelve horses were euthanized for reasons unrelated to gastrointestinal disease, and samples of the duodenum, jejunum, ileum, cecum, right dorsal colon, and small colon were collected and imaged sonographically ex vivo in an isotonic bath within 1 hour of euthanasia. For the in vivo study, ultrasonography was performed in four clinical cases, and findings were compared with histopathology. A 5-layer pattern of alternating echogenicity was observed in 70 of 72 ex vivo samples. Agreement between histologic and sonographic measurements was deemed good for all segments except the ileum. Formalin fixation did not alter the sonographic appearance or wall measurements. Findings from the four clinical cases illustrated the feasibility of also obtaining ultrasonographic images with sufficient sonographic detail in vivo to recognize wall layering and obtain comparable results to pathologic lesions. Findings from the current study can serve as background for future studies comparing ultrasonographic characteristics of the intestinal wall in horses with different gastrointestinal diseases.

Case-Control Study of Risk Factors for Equine Asthma in Texas.

Equine asthma is a common condition in horses, for which few host-related risk factors have been identified. The objective of this study was to identify host-related risk factors for the development of equine asthma. A retrospective, case-control study was performed, utilizing horses presented to the Texas A&M University, Veterinary Medical Teaching Hospital from January 2014 December 2018. Incident cases of mild to severe equine asthma (n = 37), diagnosed clinically with cytologic support of disease were examined. For each case, two control populations were identified, including one temporal control (n = 37) and one age-matched control (n = 37). Data collected included signalment, dietary and stable management, prior medical history, metabolic status, physical examination findings, and results of cytologic evaluation via bronchoalvelolar lavage or tracheal wash. Conditional logistic regression was used to compare data on equine asthma cases with data from each set of controls. Results indicated that obesity (Body Condition Score ≥ 7) was the only statistically significant risk factor for equine asthma in this population of horses. These results may aid in identification of targets for management, prevention, and further investigation into the pathogenesis of equine asthma. Early identification and intervention of horses at risk of lower airway disease could ameliorate the impact of disease.

Pocket-Sized Ultrasound Versus Traditional Ultrasound Images in Equine Imaging: A Pictorial Essay.

This pictorial essay aims to display the image quality of pocket-sized ultrasound devices and hospital-based equipment to provide clinicians visual information about the potential uses of point-of-care ultrasonography (POCUS) in equine practice. Twenty-two paired images were obtained using traditional ultrasound equipment and pocket-sized ultrasound devices from patients evaluated at veterinary teaching hospitals. Images of many common ultrasound windows and miscellaneous sonographic abnormalities were obtained using pocket-sized ultrasound equipment.

Cardiovascular findings in ponies with equine metabolic syndrome.

OBJECTIVE To determine whether hypertension, high sympathetic tone, resting and exercising arrhythmias, and echocardiographic changes consistent with hypertensive cardiomyopathy were associated with equine metabolic syndrome (EMS) in ponies. DESIGN Prospective case-control study. ANIMALS 19 privately owned ponies with a diagnosis of EMS (history of laminitis, body condition score ≥ 7/9, cresty neck score ≥ 3/5, and abnormal oral sugar test result; cases) and 20 healthy control ponies. PROCEDURES Heart rate (HR), noninvasively measured arterial blood pressure (BP), markers of autonomic tone (splenic volume and HR variability), 24-hour and exercising ECGs, and echocardiograms were compared between cases and controls. RESULTS Compared with controls, cases had a higher mean ± SD HR (44.5 ± 7.5 beats/min vs 38.6 ± 6.8 beats/min) and median mean left ventricular wall thickness (2.0 cm vs 1.8 cm). No differences were identified between groups in BP, splenic volume, HR variability, and number of premature complexes in ECGs. Mean wall thickness was correlated with BP (r = 0.54), high-frequency power (r = -0.71), and ratio of low-to high-frequency power (ϕ = 0.66). Relative wall thickness was correlated with serum insulin concentration (r = 0.71). CONCLUSIONS AND CLINICAL RELEVANCE Ponies with EMS had myocardial hypertrophy that was correlated with insulin response to an oral sugar test, sympathetic and parasympathetic tone, and BP. The heterogeneity and limited sample size of this preliminary study should be considered when drawing conclusions. Cardiovascular changes associated with this syndrome deserve further attention.

Myocardial contusion and rib fracture repair in an adult horse.

OBJECTIVE: To describe the clinical findings and management of myocardial injury secondary to blunt thoracic trauma and rib fracture in an adult horse. CASE SUMMARY: A 6-year-old Warmblood gelding presented for treatment of blunt thoracic trauma. Sonographic examination of the thorax revealed a complete, mildly comminuted fracture of the left 5th rib with a fragment overlying the left atrium and coronary artery, hemothorax, and subjective left ventricular dyskinesis. Evidence of myocardial injury included atrial fibrillation, ventricular ectopy, and increased plasma cardiac troponin I concentration. The rib fracture was repaired under general anesthesia using a wire and plate technique. The atrial fibrillation converted to normal sinus rhythm coincidentally with intraoperative local infusion of mepivicaine in administration of intercostal perineural analgesia. Continuous, resting, and exercising electrocardiograms, serial cardiac troponin I concentrations and echocardiograms were used to monitor the myocardial injury. The horse was discharged after 5 days of hospitalization. Reexaminations 3 and 15 months after the initial trauma showed healing of the fracture and no evidence of myocardial sequelae. NEW OR UNIQUE INFORMATION PROVIDED: To our knowledge, this is the first documentation of the diagnosis and monitoring of myocardial injury secondary to blunt thoracic trauma, as well as surgical repair of a rib fracture in an adult horse. Rib fractures and myocardial trauma can be successfully managed in adult horses and myocardial injury should be considered in cases of thoracic trauma.