Evaluation of atrial natriuretic peptide and cardiac troponin I concentrations for assessment of disease severity in dogs with naturally occurring mitral valve disease.

OBJECTIVE: To evaluate and compare the clinical usefulness of plasma atrial natriuretic peptide (ANP) and cardiac troponin-I (cTnI) concentrations for assessment of disease severity in dogs with naturally occurring mitral valve disease (MVD). ANIMALS: 316 dogs with MVD and 40 healthy control dogs. PROCEDURES: Each dog underwent a physical examination and echocardiographic and thoracic radiographic assessments. Blood samples were obtained and processed for measurement of plasma ANP and cTnI concentrations. Dogs with MVD were categorized into 3 groups (stages B1 [no clinical signs or evidence of cardiac enlargement], B2 [no clinical signs with evidence of cardiac enlargement], and C [history of congestive heart failure and pulmonary edema]) on the basis of American College of Veterinary Internal Medicine guidelines. Receiver operating characteristic curve analysis was used to evaluate the accuracy of plasma ANP and cTnI concentrations for assessment of MVD severity. RESULTS: Plasma ANP and cTnI concentrations increased as disease severity increased. Median plasma ANP concentrations for all 3 MVD groups and median plasma cTnI concentrations for the stage B2 and C groups were significantly greater than the corresponding concentrations for the control group. Plasma ANP concentration, but not cTnI concentration, appeared to be useful for detection of dogs with subclinical (stages B1 and B2) MVD, whereas both concentrations appeared useful for detection of dogs with stage C MVD. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that plasma ANP and cTnI concentrations should not be used independently to diagnose MVD but can be used to assess MVD severity and supplement echocardiographic findings.

Epidemiological study of indirect blood pressure measured using oscillometry in clinically healthy cats at initial evaluation.

We investigated the clinical characteristics of healthy cats in accordance with the target organ damage (TOD) risk category, on the basis of systolic blood pressure (SBP). This prospective multi-center study included 137 healthy cats. Indirect blood pressure was measured using an oscillometric technique. The median SBP in all cats was 147 mmHg (interquartile range: 134-158). On the basis of the TOD risk category, 57.7, 19.7, 21.9, and 0.7% of the cats were classified into categories I-IV, respectively. Age, sex, and body weight did not affect the SBP. This study provides basic information on the distribution of TOD risk categories in clinically healthy cats.

Diagnostic utility of cardiac troponin I in cats with hypertrophic cardiomyopathy.

BACKGROUND: Cardiac troponin I (cTnI) is useful for assessing hypertrophic cardiomyopathy (HCM) in cats. OBJECTIVE: To measure plasma cTnI concentrations in healthy cats and evaluate the clinical utility of cTnI in determining the severity of HCM. ANIMALS: Clinically healthy cats (n = 88) and cats with HCM (n = 93). METHODS: Multicenter prospective study. Cats with HCM, including hypertrophic obstructive cardiomyopathy at various stages, were diagnosed using echocardiography. Plasma cTnI concentrations were analyzed by a commercial laboratory. Receiver-operating characteristic curve analysis was used to evaluate the accuracy of plasma cTnI concentrations to detect HCM. RESULTS: The median cTnI concentration was 0.027 ng/mL (interquartile range, 0.012-0.048 ng/mL) in healthy cats. Concentrations were significantly higher in diseased cats than in healthy controls, and concentrations were significantly higher in cats with heart failure than in asymptomatic cats. A plasma cTnI concentration of 0.163 ng/mL had a sensitivity of 62.0% and specificity of 100% when used to distinguish normal cats from asymptomatic HCM cats without left atrial dilatation. A cutoff of 0.234 ng/mL had high sensitivity (95.0%) and specificity (77.8%) for assessing heart failure. The areas under the receiver-operating characteristic curves were 0.85 and 0.93, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Increased cTnI concentrations reflect the severity of HCM. If other causes of cardiac injury are ruled out, plasma cTnI concentration may be useful for predicting the severity of HCM in cats.

Relationship between indirect blood pressure and various stages of chronic kidney disease in cats.

Chronic kidney disease (CKD) is a common cause of secondary systemic hypertension in cats. We investigated the relationship between indirect blood pressure and the prevalence of systemic hypertension in various CKD stages in cats. Client-owned cats (24 control cats and 77 cats with CKD) were included. Biochemical examinations of plasma were conducted by a commercial laboratory. Diseased cats were divided into two groups based on the International Renal Interest Society (IRIS) guidelines (II and III-IV). Indirect blood pressure was measured using an oscillometric technique. Severe hypertension was diagnosed if systolic blood pressure (SBP) was ≥180 mmHg. Indirect blood pressures were significantly higher in IRIS stage III-IV than in the control cats. Of 77 cats with CKD, 25 (32.5%) had severe hypertension. The frequency of severe hypertension increased with an increase in IRIS stage; 0% in the controls, 27.6% in the IRIS stage II, and 47.4% in the IRIS stage III-IV, respectively. The indirect SBP was weakly correlated with urea nitrogen (r=0.27) and creatinine (r=0.23) concentrations in plasma. Binary logistic regression analysis showed that if plasma creatinine concentration is >3.7 mg/dl, cats with CKD had an increased risk for developing severe hypertension (P<0.001). Our results suggest that indirect blood pressure was correlated with the severity of CKD, and the prevalence of severe hypertension increased in cats with severe CKD. The risk of severe hypertension may be high in cats with severe CKD.

Fluorescein sodium-guided resection of intracranial lesions in 22 dogs.

OBJECTIVE: To evaluate the safety of an intraoperative fluorescein sodium (FS) injection and elucidate the relationships between the MRI findings, pathological diagnoses, and intraoperative staining characteristics of intracranial lesions in 22 dogs. STUDY DESIGN: Prospective case series. ANIMALS: Twenty-two dogs with intracranial lesions. METHODS: FS was intravenously administered to 22 dogs undergoing craniotomy for suspected intracranial tumors to evaluate perioperative and postoperative adverse effects. The intensities and patterns of gadolinium (Gd) enhancement on preoperative magnetic resonance imaging and intraoperative FS staining were graded, and their relationship was evaluated. Intraoperative FS staining characteristics and pathological diagnoses were compared. RESULTS: The only adverse effect noted was repetitive vomiting in 2 dogs. The intensities and patterns between preoperative Gd enhancement and intraoperative FS staining appeared to agree. High-grade glioma and histiocytic sarcoma had more intense FS staining. Lesions with strong Gd enhancement, including meningiomas and choroid plexus tumors, also had intense FS staining. CONCLUSION: The intraoperative use of FS is a simple and safe technique to guide the resection of intracranial lesions in dogs. The findings on Gd enhancement, FS staining, and histopathology appeared to agree but require validation in a larger set of cases. CLINICAL SIGNIFICANCE: The intraoperative use of FS may improve the prognosis of dogs with brain tumors by guiding the resection of lesions.

Influence of storage conditions on in vitro stability of atrial natriuretic peptide and of anesthesia on plasma atrial natriuretic peptide concentration in cats.

OBJECTIVE To investigate the in vitro stability of atrial natriuretic peptide (ANP) in plasma samples under various storage conditions and the influence of anesthesia on plasma ANP concentration in cats. ANIMALS 1 cat with congestive heart failure and 5 healthy adult mixed-breed cats. PROCEDURES A plasma sample from the cat with heart failure was serially diluted, and dilutional parallelism of ANP concentration was evaluated. Plasma samples containing aprotinin or serum samples from the 5 healthy cats were kept at room temperature (27°C) for ≤ 12 hours. Plasma samples from the same healthy cats were stored at -70°, -20°, or 4°C for ≤ 14 days. Plasma samples were obtained from the healthy cats before and during isoflurane anesthesia. Plasma ANP concentrations were measured at a commercial laboratory by use of a human ANP chemiluminescence assay. RESULTS Intra- and interassay coefficients of variation were 1.5% and 2.5%, respectively, and dilutional parallelism was established. Although ANP concentration decreased by 82.4 ± 13.6% (mean ± SD) after sample storage for 12 hours at room temperature, this decrease was prevented by aprotinin. Plasma ANP concentrations were stable for 7 days at -20°C and for 14 days at -70°C. However, concentrations decreased markedly to 57.6 ± 6.9% at -20°C and to 18.0 ± 3.0% at 4°C after 14 days. Plasma ANP concentration decreased significantly in cats during anesthesia and was correlated with blood pressure. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that aprotinin should be added routinely in preparation of plasma samples from cats for measurement of ANP concentration, and those samples, if stored, should be frozen immediately at ≤ -20°C. General anesthesia or systemic blood pressure may affect plasma ANP concentration in cats.

Indirect arterial blood pressure measurement in healthy anesthetized cats using a device that combines oscillometry with photoplethysmography.

We investigated the basic characteristics of indirect arterial blood pressure (ABP) measurement using a device that combines oscillometry and photoplethysmography in cats. Dobutamine was infused intravenously in four anesthetized cats. Direct ABP was measured by a catheter. Indirect ABP was measured from the left forelimb. Dobutamine significantly elevated both systolic arterial pressure (SAP) and mean arterial pressure (MAP) in a dose-dependent manner. The indirect SAP, MAP and diastolic arterial pressure (DAP) values were closely correlated with the direct ABP values (r=0.88, 0.89 and 0.83, respectively). The mean bias for SAP, MAP and DAP was 3.4, 0.2 and -2.4 mmHg, respectively. The indirect ABP measured by this device may be used to reliably monitor ABP changes in anesthetized cats.