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- Author or Editor: Anthony H. Tobias x
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Abstract
Objective—To investigate the mechanisms by which corticosteroid administration may predispose cats to congestive heart failure (CHF).
Animals—12 cats receiving methylprednisolone acetate (MPA) for the treatment of dermatologic disorders.
Procedure—The study was conducted as a repeated-measures design. Various baseline variables were measured, after which MPA (5 mg/kg, IM) was administered. The same variables were then measured at 3 to 6 days and at 16 to 24 days after MPA administration. Evaluations included physical examination, systolic blood pressure measurement, hematologic analysis, serum biochemical analysis, thoracic radiography, echocardiography, and total body water and plasma volume determination.
Results—MPA resulted in a substantial increase in serum glucose concentration at 3 to 6 days after administration. Concurrently, RBC count, Hct, and hemoglobin concentration as well as serum concentrations of the major extracellular electrolytes, sodium and chloride, decreased. Plasma volume increased by 13.4% (> 40% in 3 cats), whereas total body water and body weight slightly decreased. All variables returned to baseline by 16 to 24 days after MPA administration.
Conclusions and Clinical Relevance—These data suggest that MPA administration in cats causes plasma volume expansion as a result of an intra to extracellular fluid shift secondary to glucocorticoid-mediated extracellular hyperglycemia. This mechanism is analogous to the plasma volume expansion that accompanies uncontrolled diabetes mellitus in humans. Any cardiovascular disorders that impair the normal compensatory mechanisms for increased plasma volume may predispose cats to CHF following MPA administration.
Abstract
Objective—To investigate cardiovascular changes and survival times following complete interventional device occlusion of uncomplicated left-to-right shunting patent ductus arteriosus in dogs.
Design—Retrospective cohort study.
Animals—24 dogs with uncomplicated patent ductus arteriosus that was fully occluded and reevaluated within 24 hours, approximately 3 months, and 1 year after the procedure.
Procedures—Information on medical history, diagnostic imaging findings, treatment received, and survival times were obtained from medical records. Patients were allocated into 2 groups on the basis of age (< 1 year [n = 14] and ≥ 1 year [10]) at the time of the procedure. Additional follow-up information was obtained through interviews of owners and referral veterinarians.
Results—Following ductal occlusion, decreases were detected in vertebral heart scale size, left ventricular chamber diameter in diastole and in systole, left atrial dimension, fractional shortening, aortic velocity, and ventricular wall thickness. There were no differences between age groups for postocclusion changes except vertebral heart scale size. Systolic dysfunction was detected in 14 (58%) patients on the final visit. Median survival time for all dogs after ductal occlusion was > 11.5 years.
Conclusions and Clinical Relevance—Complete ductal occlusion resulted in immediate removal of the volume overload state and eventual return of cardiac chamber dimensions to reference range, suggesting regression of eccentric hypertrophy. Systolic dysfunction persisted in some dogs but appeared to be clinically unimportant. Most cardiovascular changes were independent of patient age at the time of the procedure.
Abstract
Objective—To determine whether dogs with renal failure have higher serum cardiac troponin I (cTnI) concentrations than healthy dogs.
Design—Case-control study.
Animals—31 dogs with renal failure and 51 healthy dogs.
Procedures—Serum concentrations of creatinine and cardiac troponin I, urine specific gravity, and systolic arterial blood pressure were measured for all dogs. Dogs underwent a standardized physical examination, and any dog with evidence of cardiovascular disease or other nonrenal disease was excluded from final analyses. Dogs were considered to be in renal failure when the serum creatinine concentration was ≥ 3.0 mg/dL, urine specific gravity was between 1.007 and 1.030, and renal failure had been clinically diagnosed.
Results—Dogs with renal failure had significantly higher serum cTnI concentrations (median, 0.35 ng/mL) than did healthy dogs (0.20 ng/mL). The renal failure group also had a significantly higher median systolic blood pressure (156 mm Hg) than did healthy dogs (138 mm Hg), although serum cTnI concentration was not correlated with systolic blood pressure in dogs with renal failure. There was no significant difference in age between dogs with renal failure and healthy dogs, but dogs with renal failure had significantly higher serum creatinine concentration and lower urine specific gravity.
Conclusions and Clinical Relevance—Although dogs with renal failure did not have overt clinical signs of cardiac disease, they had high serum cTnI concentrations, which may have been associated with subclinical cardiovascular disease. The cause of the high serum cTnI concentration in these dogs requires additional investigation.
Abstract
Objective—To determine clinical characteristics and clinicopathologic findings, including results of pericardial fluid analysis, and determine the outcome associated with pericardial effusion caused by cardiac lymphoma in dogs.
Design—Retrospective case series.
Animals—12 dogs.
Procedure—Medical records of affected dogs were reviewed for echocardiographic findings, radiographic findings, results of pericardial fluid analysis, clinicopathologic findings, treatment protocols, and outcomes.
Results—Pericardial effusion was detected by echocardiography in all 12 dogs, and lymphoma was detected by cytologic examination of the effusion (11/12 dogs) or histologic examination of pericardium (3/12). Large-breed dogs were overrepresented; median weight was 40.5 kg (89.1 lb). Most hematologic and biochemical changes were mild and nonspecific. Survival time for dogs treated with combination chemotherapeutic agents was 157 days and for dogs that did not receive chemotherapy survival time was 22 days. This difference was not significant, but several dogs had long-term survival.
Conclusions and Clinical Relevance—Cardiac lymphoma is an uncommon cause of pericardial effusion, and results suggest that cardiac lymphoma does not always warrant the poor prognosis of other stage V, substage b lymphomas. (J Am Vet Med Assoc 2005; 227:1449–1453)
