Effects of dietary salt intake on renal function: a 2-year study in healthy aged cats.

BACKGROUND: Increasing salt intake to promote diuresis has been suggested in the management of feline lower urinary tract disease. However, high dietary salt intake might adversely affect blood pressure and renal function. OBJECTIVES: The objective of this study was to assess the long-term effects of increased salt intake on renal function in healthy aged cats. METHODS: This study was controlled, randomized, and blinded. Twenty healthy neutered cats (10.1 ± 2.4 years) were randomly allocated into 2 matched groups. One group was fed a high salt diet (3.1 g/Mcal sodium, 5.5 g/Mcal chloride) and the other a control diet of same composition except for salt content (1.0 g/Mcal sodium, 2.2 g/Mcal chloride). Clinical examination, glomerular filtration rate, blood pressure measurement, cardiac and kidney ultrasonography, and urinary and blood tests were performed before and over 24 months after diet implementation. Statistics were performed using a general linear model. RESULTS: Sixteen cats completed the 2 year study. The only variables affected by dietary salt intake were plasma aldosterone and urinary sodium/creatinine ratio, respectively, higher and lower in the control group all over the study period and urinary specific gravity, lower in the high salt diet group at 3 months. CONCLUSIONS AND CLINICAL IMPORTANCE: Glomerular filtration rate (GFR), blood pressure, and other routine clinical pathological variables in healthy aged cats were not affected by dietary salt content. The results of this 2 year study do not support the suggestion that chronic increases in dietary salt intake are harmful to renal function in older cats.

Echocardiographic and tissue Doppler imaging alterations associated with spontaneous canine systemic hypertension.

BACKGROUND: Feline systemic arterial hypertension (SHT) is associated with a wide spectrum of left ventricular (LV) geometric patterns as well as diastolic, and to a lesser extent, systolic myocardial dysfunction. However, little is known about SHT-related cardiac changes in dogs. HYPOTHESIS: SHT in dogs is responsible for morphological and functional cardiac alterations. ANIMALS: Thirty dogs with spontaneous untreated SHT and 28 age- and body weight-matched healthy dogs as controls. METHODS: Prospective observational study. Conventional echocardiography and 2-dimensional color tissue Doppler imaging were performed in SHT dogs by trained observers and compared with controls. RESULTS: Forty-seven percent of SHT dogs (14/30) had diffuse concentric hypertrophy. None had left atrial dilatation and 10/30 (33%) had aortic insufficiency (AoI) associated with proximal aortic dilatation. Longitudinal diastolic left ventricular free wall (LVFW) motion was altered in all SHT dogs at the base (early to late diastolic wave ratio, E/A = 0.5 ± 0.1 versus 1.3 ± 0.3 for controls, P < .0001) and the apex (E/A = 1.6 ± 1.7 versus 3.9 ± 3.1, P < .05). Longitudinal motion of the interventricular septum at the base (E/A = 0.7 ± 0.4 versus 1.1 ± 0.1, P < .01) and radial LVFW motion in the subendocardium (E/A = 0.9 ± 0.5 versus 1.6 ± 0.3, P < .01) were also altered in dogs with SHT. Longitudinal LVFW systolic velocities and gradients were also significantly decreased (P < .05) in SHT dogs. CONCLUSION AND CLINICAL IMPORTANCE: As in SHT in cats, SHT in dogs is associated with myocardial dysfunction independently of the presence of myocardial hypertrophy. However, unlike feline SHT, it results in a homogeneous LV geometric pattern with a relatively high prevalence of AoI.

Direct myocardial implantation of human embryonic stem cells in a dog model of Duchenne cardiomyopathy reveals poor cell survival in dystrophic tissue.

Duchenne muscular dystrophy is characterized by progressive muscle weakness and early death resulting from dystrophin deficiency. Spontaneous canine muscular disorders are interesting settings to evaluate the relevance of innovative therapies in human using pre-clinical trials.

Prospective echocardiographic and tissue Doppler imaging screening of a population of Maine Coon cats tested for the A31P mutation in the myosin-binding protein C gene: a specific analysis of the heterozygous status.

BACKGROUND: A mutation in the sarcomeric gene coding for the myosin-binding protein C gene has been identified in a colony of Maine Coon cats with hypertrophic cardiomyopathy (MyBPC3-A31P mutation). However, the close correlation between genotype and phenotype (left ventricular hypertrophy [LVH] and dysfunction) has never been assessed in a large population, particularly in heterozygous (Hetero) cats. OBJECTIVES: To investigate LV morphology and function with echocardiography and tissue Doppler imaging (TDI) in a population of Maine Coon cats tested for the MyBPC3-A31P mutation with focus on Hetero animals. ANIMALS: Ninety-six Maine Coon cats. METHODS: Prospective observational study. Cats were screened for the MyBPC3-A31P mutation and examined with both echocardiography and 2-dimensional color TDI. RESULTS: Fifty-two out of 96 cats did not have the mutation (wild-type genotype, Homo WT), 38/96 and 6/96 were Hetero- and homozygous-mutated (Homo M) cats, respectively. Only 11% of Hetero cats (4/38) had LVH and 29% (10/34) of Hetero cats without LVH were >4 years old (4.1-11.5 years). LVH was also detected in 2 Homo WT cats (4%). A significantly decreased (P < .05) longitudinal E/A (ratio between early and late diastolic myocardial velocities) in the basal segment of the interventricular septum was observed in Hetero cats without LVH (n = 34) compared with Homo WT cats without LVH (n = 50), thus confirming that the Hetero status is associated with regional diastolic dysfunction (P < .05). CONCLUSIONS: The heterozygous status is not consistently associated with LVH and major myocardial dysfunction. Moreover, Homo WT cats can also develop LVH, suggesting that other genetic causes might be implicated.

Comparison of 3 ultrasound methods for quantifying left ventricular systolic function: correlation with disease severity and prognostic value in dogs with mitral valve disease.

BACKGROUND: End-systolic volume index (ESVI) is a marker of systolic function, which can be assessed by the geometric (GM, based on Teichholz formula) or 2 planimetric methods (PM, Simpson's derived and length area methods). HYPOTHESIS: Systolic dysfunction (SyD) may be observed in dogs with mitral valve disease (MVD) and is better assessed by PM than GM, which does not take into account the longitudinal left ventricular systolic shortening. ANIMALS: Six healthy dogs were used to determine the variability of the tested variables (Study 1). These variables were then prospectively assessed (Study 2) in 101 small breed dogs: 77 dogs with MVD and 24 healthy controls (CD). METHODS: ESVI was measured by GM and PM in awake dogs. RESULTS: All within- and between-day coefficients of variation were <11% (Study 1). For Study 2, a nonlinear overestimation of ESVI was observed by GM compared with PM. PM-derived ESVI was significantly increased in ISACHC class 3 dogs compared with ISACHC class 1 dogs and exerted a significant influence on cardiac events at 5 months in dogs with MVD from ISACHC classes 2 and 3 (P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: ESVI can be calculated by GM and PM with good repeatability and reproducibility. However, GM overestimates ESVI in a nonlinear way. Therefore, PM-derived ESVI should be preferred for the detection of SyD that is present at the late stages of the disease.

Effect of benazepril on survival and cardiac events in dogs with asymptomatic mitral valve disease: a retrospective study of 141 cases.

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEIs) improve quality of life and extend the life span of dogs with naturally acquired ISACHC class II-III congestive heart failure (CHF). However, their effects on asymptomatic heart disease remain controversial. HYPOTHESIS: Benazepril (BNZ), an ACEI, could have beneficial effects at the asymptomatic stage of degenerative mitral valve disease (MVD). ANIMALS: Dogs with ISACHC class Ia MVD and moderate-to-severe mitral regurgitation (MR) assessed by the color Doppler mapping technique at entry (Day 0) were retrospectively included. METHODS: Dogs were assigned to the treated group (BNZ group) if they received BNZ (and no other cardiac medication) from Day 0 or to the untreated group (UT group) if they did not receive any cardioactive treatment until occurrence of CHF. RESULTS: A total of 141 dogs were included in the study, 66 in the BNZ group (dosage: 0.30 +/- 0.13 mg/kg) and 75 in the UT group. In the population (n = 93) including all breeds except Cavalier (CKC) and King Charles Spaniels (KC), median survival time to all causes of death in the BNZ group (n = 34, 3.3 years) was significantly longer than in the UT group (n = 59, 1.9 years) as was time to cardiac event (P < .05). Conversely, no effect of the BNZ treatment was observed in the CKC and KC population. CONCLUSIONS AND CLINICAL RELEVANCE: BNZ had beneficial effects in asymptomatic dogs other than CKC and KC affected by MVD with moderate-to-severe MR. Breed distribution should be taken into account for interpretation of clinical trials performed in dogs with cardiac disease.

Congenital heart diseases in the boxer dog: A retrospective study of 105 cases (1998-2005).

Subaortic stenosis (SAS) is one of the most common congenital heart diseases (CHD) in dogs with Boxers being predominantly affected. However, the increasing availability of modern diagnostic imaging systems now allows a better assessment of cardiac morphology and function, thereby facilitating early detection of CHD in awake animals. In this context, the case records of Boxer dogs diagnosed with CHD using echocardiography combined with Doppler mode, were retrospectively reviewed (1998-2005). One hundred and five Boxers exhibiting either a single CHD (53/105, 50.5%) or association of several CHD (52/105, 49.5%) were included. The most common CHD was atrial septal defect (ASD) observed in 56.2% of these animals (59/105), followed by mitral dysplasia (58/105, 55.2%), and SAS (49/105, 46.7%). SAS was associated with one or two CHD in 29.5% of cases (31/105). Most of the dogs with a low intensity left heart base systolic murmur had an isolated ASD whereas most of the dogs with a similar but high intensity murmur had SAS, either isolated or associated with a concurrent CHD. The incidence of ASD and mitral dysplasia in Boxer dogs is higher than previously assumed, and ASD is a common cause of left heart base systolic murmur in this breed of dog. This confirms that the detection of such a murmur should not be used as the unique criterion for diagnostic confirmation of SAS.

Persistent truncus arteriosus in a 6-year-old cat.

Truncus arteriosus (TA) was diagnosed in a 6-year-old neutered female domestic short-haired cat by two-dimensional and M-mode echocardiography, colour flow imaging and spectral Doppler examinations. The lesion was characterized by a single large artery originating from the right ventricle. A single ascending aorta and a single pulmonary trunk arose from the common arterial trunk. The residual pulmonary trunk immediately split into left and right branches. The lesion was identified as a type I (TA). This case is of interest because it is the first reported echo-Doppler description of such a malformation in felines, and because of the age of the cat at the time of diagnosis.

Longitudinal left ventricular myocardial dysfunction assessed by 2D colour tissue Doppler imaging in a dog with systemic hypertension and severe arteriosclerosis.

A 12-year-old sexually intact male Vendee Griffon Basset was presented for acute pulmonary oedema. Severe systemic systolic arterial hypertension (SAH) was diagnosed (290 mmHg). Despite blood and abdominal ultrasound tests, the underlying cause of the systemic hypertension could not be determined, and primary SAH was therefore suspected. Conventional echocardiography showed eccentric left ventricular hypertrophy with normal fractional shortening. Despite this apparent normal systolic function, 2D colour tissue Doppler imaging (TDI) identified a marked longitudinal systolic left ventricular myocardial alteration, whereas radial function was still preserved. Three months later, the dog underwent euthanasia because of an acute episode of distal aortic thromboembolism. Necropsy revealed severe aortic and iliac arteriosclerosis. SAH related to arteriosclerosis is a common finding in humans, but has not been previously described in dogs. Moreover, its consequence on longitudinal myocardial function using TDI has never been documented before in this species.