13 Feb 2024
Our latest Research Review sees Alex Gough delving into more veterinary studies in companion animal medicine, including investigations into infrared imaging, nasogastric tube placement and AI accuracy.
Alex Gough
Job Title
Feline hypertrophic cardiomyopathy (HCM) is a common heart disease in cats, but effective treatment options remain limited, in contrast to the improvements in treatment of heart disease in dogs over recent years.
Kapan et al1 performed a double-blinded randomised placebo-controlled trial to investigate the use of rapamycin, a drug that has been shown to prevent and reverse cardiac hypertrophy in experimental models, in feline hypertrophic HCM. A total of 43 cats with subclinical HCM were included in the study.
A panel of tests including echocardiography, total thyroxine, pro B-type natriuretic peptide, cardiac troponin and blood pressure were measured at baseline and follow-ups up to six months. At the end of the study, maximum left ventricular wall thickness was significantly lower in the rapamycin treated cats compared to placebo. No difference in adverse effects was reported between the two groups. The authors concluded that rapamycin was well-tolerated in cats, and may prevent or at least delay progressive left ventricular hypertrophy in cats with subclinical HCM.
Splenic neoplasia is less common in cats than dogs, but nevertheless is an important indication for splenectomy in this species.
Rossanese et al2 performed a retrospective study to report the prevalence of splenic neoplasia in cats undergoing splenectomy and to assess factors that were associated with outcome. A total of 62 cats presenting to four UK-based referral hospitals across 17 years were included in the study. Fifty of the cats had splenic malignancy, with mast cell tumour the most common at 42%, followed by haemangiosarcoma at 40%, and lymphoma only 6%, although the low prevalence of the latter in this study may reflect the fact that lymphoma is not usually treated surgically. Just under a quarter (24%) of cases presented with spontaneous haemoabdomen, and all of these had splenic neoplasia.
Cytology was 73% accurate in diagnosis of malignancy, but 100% accurate for mast cell tumour. The median survival time for cats with non-neoplastic splenic disease was 715 days, compared to 136 days for cats with neoplasia. Cats with mast cell tumours survived longer than cats with haemangiosarcomas. Metastatic disease and anaemia at presentation were associated with a poorer survival time, and the presence of anaemia, spontaneous haemoabdomen and the finding of a splenic mass on imaging increased the likelihood of the presence of haemangiosarcoma.
The authors concluded that benign splenic masses were uncommon, and the presence of spontaneous haemoabdomen was a marker for neoplasia in cats with splenic disease.
Infrared thermography (IRT) is an imaging technique using detection of infrared radiation to evaluate local temperature differences.
Finstad et al3 used the technology to evaluate its utility in detecting small intestinal foreign bodies in dogs. In this prospective study, 49 dogs were included. IRT was used to compare the small intestinal surface temperature differences at the site of foreign bodies and the sections of bowels oral and aboral to the obstruction, before and after surgical removal. No significant difference was reported in surface temperature between the different segments of bowel evaluated, but after foreign body removal, a significant overall drop in surface temperature was noted. However, although surface temperature also decreased following removal of a hard foreign body in the oral segment of bowel, it increased in that segment following removal of a soft foreign body.
The authors concluded that IRT may be useful to identify changes in surface temperature of the bowel associated with foreign bodies, but more studies are required to ascertain whether this is clinically useful.
Doxapram was previously routinely used to stimulate the onset of respiration in puppies immediately after delivery – especially after caesarean section. However, lack of evidence for its efficacy has meant that it is now used less commonly.
Hyndman et al4 performed a randomised double-blinded trial to assess the efficacy and safety of the drug in this setting. Seven-day mortality and repeated Apgar scores were the outcome measures. After delivery by caesarean section, a baseline Apgar score was recorded and then an intralingual injection of either saline or doxapram was administered. Included in the study were 171 puppies from 45 caesareans. No significant difference was reported in the odds of seven-day survival or a maximal Apgar score between the two groups.
The authors concluded that no evidence exists that suggests intralingual doxapram is useful or harmful in non-apnoeic puppies delivered by elective caesarean section.
Feeding tubes are recommended for patients that have working gastrointestinal tracts but are not taking in adequate nutrition voluntarily. However, misplacement of feeding tubes can lead to severe adverse effects.
Ramesh et al5 performed a prospective observational study to compare four point of care techniques used to assess nasogastric (NG) tube placement, with radiographs used as the reference standard. The four point of care techniques were air inflation with auscultation, fluid aspiration with pH measurement, ultrasonography and capnography. The study included 51 dogs which had NG tubes placed blindly, after which the four techniques were performed. Each technique was scored as to whether the clinician believed the tube to be in the gastrointestinal technique. Sensitivity, specificity and accuracy varied greatly between the techniques, with neck ultrasound the most accurate. Fluid aspiration had high specificity but low sensitivity. However, orthogonal view radiography was still most accurate method for assessing correct NG tube placement.
Artificial intelligence (AI) is growing rapidly in human medicine, but less so in the veterinary field. Nevertheless, the veterinary profession is catching up.
Pomerantz et al6 performed a retrospective diagnostic accuracy study on a commercially available AI product to assess its accuracy in detecting pulmonary nodules and masses. Included in the study were 56 radiographs with pulmonary nodules or masses diagnosed by CT, cytology or histology together with 32 controls. The AI system correctly classified 30 out of 32 of the control cases, but only 31 out of 56 of the confirmed cases, for a sensitivity of 55.4% and a specificity of 94%.
The authors discussed the current relevance of AI in the veterinary field.
Oclacitinib is a Janus kinase inhibitor used in the treatment of atopic dermatitis in dogs.
Hernandez-Bures et al7 performed a retrospective study to assess whether oclacitinib is useful in the treatment of pemphigus foliaceous (PF) in dogs. A total of 30 dogs with PF treated with either oclacitinib or azathioprine in combination with glucocorticoids were included in the study. No difference in induction of remission was found between the groups, with 13 out of 15 dogs in the azathioprine group experiencing partial or complete remission, compared to 11 out of 15 in the oclacitinib group. No significant difference was reported in ability to reduce glucocorticoid dose. The authors concluded that oclacitinib is a useful drug for the treatment of canine PF.
