Takahiro Teshima

Quantitative assessment of mitral regurgitation (MR) in dogs with myxomatous mitral valve disease (MMVD) is influenced by the method used to estimate left ventricular volume. This study aimed to evaluate the impact of different left ventricular volume estimation methods on quantitative MR assessment, using the modified Simpson’s method of discs (Disc method) as a reference. Echocardiographic data from 167 dogs with MMVD and 19 healthy control dogs were analyzed. Regurgitant volume (RVol), body size-normalized RVol, and regurgitant fraction (RF) were calculated using diameter-based methods (Cube, Gibson, Meyer, and Teichholz) and compared with values obtained using the Disc method. All diameter-based methods showed significant positive correlations with the Disc method. However, Bland–Altman analyses demonstrated wide limits of agreement and systematic bias. Between-method discrepancies increased with advancing disease stage, with diameter-based methods tending to overestimate RVol and RF, particularly in dogs classified as American College of Veterinary Internal Medicine (ACVIM) stages B2 and C/D. Although relative trends in regurgitant indices were consistent across methods, substantial differences were observed in absolute values. These findings indicate that diameter-based methods are not interchangeable with the Disc method for absolute quantification of MR severity in dogs with MMVD, especially in advanced disease stages.

Mesenchymal stromal cells (MSCs) are a promising cell source for the treatment of dogs with refractory chronic inflammatory enteropathy (CIE). Although sev

Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy in cats and is classified as obstructive (HOCM) or non-obstructive based on anatomical differences in the left ventricular outflow tract (LVOT). In severe obstructive cases, while beta-blockers are the recommended initial treatment in humans, some patients exhibit treatment resistance. For these cases, the addition of the antiarrhythmic agent disopyramide is common. However, its use in cats has only been documented in a case report. In this study, the use of disopyramide resulted in a significant reduction in the LVOT velocity and cardiac troponin I levels. Additionally, no significant adverse effects were observed. These findings suggest that disopyramide could be a potential therapeutic option for the treatment in cats with HOCM.

Hypertrophic cardiomyopathy (HCM) is the most common cardiac disease in cats. HCM is classified into obstructive HCM (HOCM) and non-obstructive HCM (HNCM) forms based on the presence or absence of left ventricular outflow tract obstruction (LVOTO). In humans, LVOTO is a known poor prognostic factor and a target for therapeutic intervention. In contrast, LVOTO has been reported not to contribute to prognosis in cats. This study demonstrated significant correlations between cTnI levels and a maximal LV outflow tract velocity (LVOTV). This finding suggests that LVOTO is associated with myocardial cell injury.

A 12-year-old castrated male Labrador Retriever presented with asymptomatic hypercalcemia. Based on elevated parathyroid hormone levels and an enlarged parathyroid gland, primary hyperparathyroidism was suspected, and parathyroidectomy was performed, but the hypercalcemia did not improve. Histopathology of three resected parathyroid glands revealed hyperplasia and hypertrophy of the principal cells. After surgery, the fractional excretion of calcium examined in a spot urine sample was close to that in healthy dogs, but lower than that in a dog with primary hyperparathyroidism. Autoantibodies against calcium-sensing receptor (CaSR) were confirmed by incubating a cell line expressing canine CaSR with a serum sample from the hypercalcemic dog. Our report is the first to describe the diagnosis of acquired hypocalciuric hypercalcemia in a dog.

An 8-year-old Leonberger receiving immunosuppressive treatment with clinical signs of acute dyspnea, cyanosis, and difficulty standing was referred to our institution (Day 1). Treatment including oxygen, clopidogrel, and low-molecular-weight heparin was initiated for suspected pulmonary thrombosis. However, exertional dyspnea persisted until Day 10, and increased tricuspid regurgitation velocity, pulmonary vascular resistance, and McConnell's signs also were observed. Thus, beraprost sodium was administered PO on Day 11 to treat suspected pulmonary hypertension. On Day 13, contrast-enhanced computed tomography identified extensive contrast defects in the pulmonary arteries, and IV monteplase was administered on Days 14 and 18, with marked improvement in respiratory status and exertional dyspnea on Day 20. Right ventricular function and McConnell signs also improved, and tricuspid regurgitation velocity and pulmonary vascular resistance decreased. On Day 250, echocardiography indicated further improvement in pulmonary hypertension pathophysiology. The patient was still progressing well with antithrombotic and pulmonary vasodilator treatment 400 days later.

Previous reports have shown that various oral pulmonary vasodilators are effective against canine pulmonary hypertension (PH). However, no studies have compared their hemodynamic effects. We aimed to compare the hemodynamic effects of 15 µg/kg beraprost sodium, 1.0 mg/kg sildenafil, and their combination, in dogs with experimentally induced mitral regurgitation. This experimental crossover study evaluated the hemodynamic and functional effects of oral pulmonary vasodilators by application of right-sided heart catheterization and echocardiography. Beraprost significantly decreased pulmonary and systemic vascular resistance. Additionally, beraprost increased right-ventricular stroke volume and left-ventricular cardiac output without worsening left-heart size and left-atrial pressure. The pulmonary vasodilatory effects of sildenafil were stronger, and its systemic vasodilatory effects were weaker than those of beraprost. However, sildenafil significantly increased the left-ventricular volume, left-atrial pressure indicator, and right-ventricular cardiac output. Combination therapy resulted in the strongest pulmonary and systemic vasodilating effects without worsening the left-heart size and left-atrial pressure indicators. Both beraprost and sildenafil were effective against canine PH; however, sildenafil was associated with the risk of worsening left-heart loading. Combination therapy with beraprost and sildenafil synergistically dilated pulmonary and systemic vessels, indicating a more potent treatment option for severe PH cases.