Assessment of Canine Pancreas-Specific Lipase and Outcomes in Dogs with Hemodialysis-Dependent Acute Kidney Injury

Background

Renal replacement therapies can be life‐saving for dogs with severe acute kidney injury (AKI), however, comorbidities including pancreatitis might affect outcome.

Hypothesis/Objectives

To investigate the prevalence of pancreas‐specific lipase (Spec cPL) measurements consistent with pancreatitis (≥400 μg/L) in dogs undergoing intermittent hemodialysis (IHD) for treatment of AKI and to determine whether there were associations between 30‐days outcomes and Spec cPL measurements.

Animals

Fifty‐three client‐owned dogs presented to teaching hospitals between November 2008 and September 2016 that underwent IHD.

Methods

Retrospective medical record review from dogs that received IHD for management of AKI and also had a Spec cPL measurement. Association between survival, dialysis‐dependency, and Spec cPL measurements was assessed.

Results

Forty of 53 (76%) dogs were alive at 30‐days and 33/53(62%) had a Spec cPL result ≥400 μg/L. Spec cPL was not significantly different either between surviving (635.5 μg/L, range 29–1,001) and nonsurviving dogs (860 μg/L, range 56–1,001; P = 0.75) or between dialysis‐dependent (1,001 μg/L, range 177–1,001) and nondialysis‐dependent dogs (520 μg/L, range 29–1,001; P = 0.08). Spec cPL ≥400 μg/L was not significantly associated either with survival (P = 0.74) or dialysis‐dependency (P = 0.33).

Conclusions and Clinical Importance

Results revealed a high prevalence of Spec cPL ≥400 μg/L in dogs with AKI treated with IHD. No significant associations between Spec cPL and survival or dialysis‐dependency in dogs with AKI at 30 days were identified in the current study, however, the latter could be due to lack of power in this study.

The Use of Darbepoetin to Stimulate Erythropoiesis in the Treatment of Anemia of Chronic Kidney Disease in Dogs

Background

Darbepoetin alfa (darbepoetin) is an erythropoiesis‐stimulating agent used for the treatment of anemia secondary to chronic kidney disease (CKD) in dogs, but reports describing response are lacking.

Hypothesis/Objectives

To evaluate the effectiveness of darbepoetin in dogs with anemia secondary to CKD, dosing protocols, and adverse events.

Animals

Thirty‐three client‐owned dogs with naturally occurring CKD, including 26 with comorbidities.

Methods

Multi‐institutional retrospective study.

Results

The median starting dosage and highest dosage of darbepoetin administered were 0.5 and 0.8 μg/kg SC once weekly, respectively. Response to treatment was defined as achieving a packed cell volume (PCV) ≥30% or an increase in PCV ≥10%. Twenty‐eight of 33 dogs (85%) achieved a PCV ≥30% and 22 of 33 (67%) dogs achieved an increase in PCV ≥10%. Median time to achieve a PCV ≥30% was 29 days. A higher starting dosage was associated with achieving an increase in PCV ≥10% (P = .01). No dog sustained a response at a dosing interval >q21d. Potential adverse events included increased blood pressure requiring treatment (n = 12), seizures (n = 5), vomiting (n = 3), diarrhea (n = 3), and possible pure red cell aplasia (PRCA) (n = 2).

Conclusions and Clinical Importance

Darbepoetin, when combined with treatment of comorbidities, is an effective treatment for anemia secondary to CKD in dogs. A dosing interval >q21d was ineffective at maintaining a response to treatment. PRCA was a possible adverse event in 2 of 33 dogs (6%).

Validation of a Clinical Scoring System for Outcome Prediction in Dogs with Acute Kidney Injury Managed by Hemodialysis

Background

A scoring system for outcome prediction in dogs with acute kidney injury (AKI) recently has been developed but has not been validated.

Hypothesis

The scoring system previously developed for outcome prediction will accurately predict outcome in a validation cohort of dogs with AKI managed with hemodialysis.

Animals

One hundred fifteen client‐owned dogs with AKI.

Methods

Medical records of dogs with AKI treated by hemodialysis between 2011 and 2015 were reviewed. Dogs were included only if all variables required to calculate the final predictive score were available, and the 30‐day outcome was known. A predictive score for 3 models was calculated for each dog. Logistic regression was used to evaluate the association of the final predictive score with each model's outcome. Receiver operating curve (ROC) analyses were performed to determine sensitivity and specificity for each model based on previously established cut‐off values.

Results

Higher scores for each model were associated with decreased survival probability (P < .001). Based on previously established cut‐off values, 3 models (models A, B, C) were associated with sensitivities/specificities of 73/75%, 71/80%, and 75/86%, respectively, and correctly classified 74–80% of the dogs.

Conclusions and Clinical Relevance

All models were simple to apply and allowed outcome prediction that closely corresponded with actual outcome in an independent cohort. As expected, accuracies were slightly lower compared with those from the previously reported cohort used initially to develop the models.

Urinary Neutrophil Gelatinase-associated Lipocalin as a Marker for Identification of Acute Kidney Injury and Recovery in Dogs with Gentamicin-induced Nephrotoxicity

BACKGROUND

Acute kidney injury (AKI) is associated with high mortality rates in dogs, which may be a consequence of late recognition using traditional diagnostic tests. Neutrophil gelatinase-associated lipocalin (NGAL) is a protein-induced during kidney injury that may identify AKI earlier than traditional tests.

OBJECTIVES/HYPOTHESIS

To evaluate urinary NGAL (uNGAL) and uNGAL-to-urinary creatinine ratio (UNCR) as early markers of kidney injury and recovery in an AKI model in dogs. It was hypothesized that these markers would document AKI earlier than serum creatinine concentration.

ANIMALS

Five purpose-bred dogs.

METHODS

Prospective study. Acute kidney injury, defined as a > 50% increase in serum creatinine concentration above baseline, was induced in dogs by gentamicin administration (8-10 mg/kg SC q8h). Blood and urine collected for biochemical analyses and uNGAL and urinary creatinine concentrations, respectively, during AKI induction and recovery.

RESULTS

Acute kidney injury was diagnosed significantly earlier based on a 7-fold increase in UNCR compared to a > 50% increase in serum creatinine concentration (day 8; range, 2-10 mg/dl vs day 16; range, 14-19 mg/dl; P = .009). During recovery, the initial decrease in UNCR preceded the decrease in serum creatinine concentration by a median of 2 days. The uNGAL changes paralleled UNCR changes, but the increase in uNGAL was triphasic; the initial peak occurred earlier than UNCR (median, day 11 versus median, day 19).

CONCLUSIONS AND CLINICAL IMPORTANCE

The UNCR was early marker of gentamicin-induced AKI and its decrease documented onset of renal recovery. Additional studies are needed to validate this marker in dogs with naturally occurring renal injury.

Evaluation of Canine Pancreas-Specific Lipase Activity, Lipase Activity, and Trypsin-Like Immunoreactivity in an Experimental Model of Acute Kidney Injury in Dogs

Background

Diagnosis of pancreatitis in dogs is complicated by extrapancreatic disorders that can alter the results of laboratory tests. Extrapancreatic disorders can also affect the diagnosis of exocrine pancreatic insufficiency (EPI). The effects of acute kidney injury (AKI) on pancreas‐specific lipase activity (Spec cPL^® Test), serum lipase activity and trypsin‐like immunoreactivity (TLI) in dogs have not been evaluated.

Hypothesis/Objectives

Serum Spec cPL, lipase activity, and TLI concentrations will increase secondary to decreased kidney function.

Animals

Five purpose‐bred dogs.

Methods

Experimental prospective study. Gentamicin was used to induce AKI in 5 purpose‐bred dogs. Serum samples were collected for measurement of creatinine, Spec cPL, lipase activity and TLI over 60 days, during both induction of, and recovery from, AKI.

Results

All dogs developed and recovered from AKI. Six of 52 (12%) serum Spec cPL concentrations were increased (2 in the equivocal zone and 4 consistent with pancreatitis) in 2 of 5 (40%) dogs. Two of 51 (4%) serum lipase activity values were increased in 2 of 5 dogs. Serum TLI was increased above the reference range in 17 of 50 (34%) samples in 3 of 5 dogs. For all biomarkers, there was no consistent correlation with increases in serum creatinine concentration.

Conclusions and Clinical Importance

Decreased renal excretion during experimental AKI did not cause consistent and correlated increases in serum Spec cPL, lipase activity, or TLI in this cohort of dogs.

Cardiovascular-renal axis disorders in the domestic dog and cat: a veterinary consensus statement

OBJECTIVES

There is a growing understanding of the complexity of interplay between renal and cardiovascular systems in both health and disease. The medical profession has adopted the term "cardiorenal syndrome" (CRS) to describe the pathophysiological relationship between the kidney and heart in disease. CRS has yet to be formally defined and described by the veterinary profession and its existence and importance in dogs and cats warrant investigation. The CRS Consensus Group, comprising nine veterinary cardiologists and seven nephrologists from Europe and North America, sought to achieve consensus around the definition, pathophysiology, diagnosis and management of dogs and cats with "cardiovascular-renal disorders" (CvRD). To this end, the Delphi formal methodology for defining/building consensus and defining guidelines was utilised.

METHODS

Following a literature review, 13 candidate statements regarding CvRD in dogs and cats were tested for consensus, using a modified Delphi method. As a new area of interest, well-designed studies, specific to CRS/CvRD, are lacking, particularly in dogs and cats. Hence, while scientific justification of all the recommendations was sought and used when available, recommendations were largely reliant on theory, expert opinion, small clinical studies and extrapolation from data derived from other species.

RESULTS

Of the 13 statements, 11 achieved consensus and 2 did not. The modified Delphi approach worked well to achieve consensus in an objective manner and to develop initial guidelines for CvRD.

DISCUSSION

The resultant manuscript describes consensus statements for the definition, classification, diagnosis and management strategies for veterinary patients with CvRD, with an emphasis on the pathological interplay between the two organ systems. By formulating consensus statements regarding CvRD in veterinary medicine, the authors hope to stimulate interest in and advancement of the understanding and management of CvRD in dogs and cats. The use of a formalised method for consensus and guideline development should be considered for other topics in veterinary medicine.

World Small Animal Veterinary Association Renal Pathology Initiative: Classification of Glomerular Diseases in Dogs

Evaluation of canine renal biopsy tissue has generally relied on light microscopic (LM) evaluation of hematoxylin and eosin-stained sections ranging in thickness from 3 to 5 µm. Advanced modalities, such as transmission electron microscopy (TEM) and immunofluorescence (IF), have been used sporadically or retrospectively. Diagnostic algorithms of glomerular diseases have been extrapolated from the World Health Organization classification scheme for human glomerular disease. With the recent establishment of 2 veterinary nephropathology services that evaluate 3-µm sections with a panel of histochemical stains and routinely perform TEM and IF, a standardized objective species-specific approach for the diagnosis of canine glomerular disease was needed. Eight veterinary pathologists evaluated 114 parameters (lesions) in renal biopsy specimens from 89 dogs. Hierarchical cluster analysis of the data revealed 2 large categories of glomerular disease based on the presence or absence of immune complex deposition: The immune complex-mediated glomerulonephritis (ICGN) category included cases with histologic lesions of membranoproliferative or membranous patterns. The second category included control dogs and dogs with non-ICGN (glomerular amyloidosis or focal segmental glomerulosclerosis). Cluster analysis performed on only the LM parameters led to misdiagnosis of 22 of the 89 cases-that is, ICGN cases moved to the non-ICGN branch of the dendrogram or vice versa, thereby emphasizing the importance of advanced diagnostic modalities in the evaluation of canine glomerular disease. Salient LM, TEM, and IF features for each pattern of disease were identified, and a preliminary investigation of related clinicopathologic data was performed.

Glomerular filtration rate, urine production, and fractional clearance of electrolytes in acute kidney injury in dogs and their association with survival

Background

Acute kidney injury (AKI) is common in dogs. Few studies have assessed sequential changes in indices of kidney function in dogs with naturally occurring AKI.

Objective

To document sequential changes of conventional indices of renal function, to better define the course of AKI, and to identify a candidate marker for recovery.

Animals

Ten dogs with AKI.

Methods

Dogs were prospectively enrolled and divided into surviving and nonsurviving dogs. Urine production was measured with a closed system for 7 days. One and 24‐hour urinary clearances were performed daily to estimate solute excretion and glomerular filtration rate (GFR). Solute excretion was calculated as an excretion ratio (ER) and fractional clearance (FC) based on both the 1‐ and 24‐hour urine collections.

Results

Four dogs survived and 6 died. At presentation, GFR was not significantly different between the outcome groups, but significantly (P = .03) increased over time in the surviving, but not in the nonsurviving dogs. Fractional clearance of Na decreased significantly over time (20.2–9.4%, P < .0001) in the surviving, but not in the nonsurviving dogs. The ER and FC of solutes were highly correlated (r, 0.70–0.95).

Conclusion and Clinical Impact

Excretion ratio might be used in the clinical setting as a surrogate marker to follow trends in solute excretion. Increased GFR, urine production, and decreased FC of Na were markers of renal recovery. The FC of Na is a simple, noninvasive, and cost‐effective method that can be used to evaluate recovery of renal function.

Evaluation of neutrophil gelatinase-associated lipocalin as a marker of kidney injury in dogs

BACKGROUND

Acute kidney injury (AKI) is a common and often fatal disorder in dogs.

HYPOTHESIS

Urine neutrophil gelatinase-associated lipocalin (NGAL)/creatinine ratio is a sensitive and specific biomarker of AKI in dogs.

ANIMALS

Ninety-four dogs.

METHODS

Prospective study. Dogs were classified as follows: (1) healthy dogs, (2) dogs with lower urinary tract disorders, (3) dogs with chronic kidney disease (CKD), (4) dogs with azotemic International Renal Interest Society (IRIS) AKI Grades II-V, and (5) dogs with IRIS AKI Grade I (nonazotemic). Urinary NGAL was quantitated in each dog using an ELISA assay and concentrations were expressed as a ratio to urinary creatinine concentration from the same specimen, and designated the urinary NGAL/creatinine ratio (UNCR).

RESULTS

There was a significant difference in UNCR among the study groups (P < .001). Both the azotemic and nonazotemic AKI groups had higher UNCR when compared with all other groups (P < .001 for all pairs). There was a statistically significant difference in UNCR between dogs diagnosed with CKD compared with dogs with lower urinary tract diseases (P = .005) as well as between dogs with CKD and healthy dogs (P = .001). Receiver operator characteristics (ROC) analysis of UNCR as an indicator of azotemic and nonazotemic AKI had an area under the ROC curve of 0.94 and 0.96, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

NGAL/creatinine ratio is a sensitive and specific marker of AKI. It can be used to screen patients at risk for AKI and can be utilized to diagnose milder forms of AKI potentially earlier in the course of the disease.

A retrospective study of acute kidney injury in cats and development of a novel clinical scoring system for predicting outcome for cats managed by hemodialysis

BACKGROUND

Information regarding acute kidney injury (AKI) in cats is limited, and there are no reliable tools to objectively assess disease severity and predict outcome.

OBJECTIVES

To assess clinical signs, clinicopathologic abnormalities, etiology, and outcome of cats with AKI, and to develop models using clinical metrics and empirically derived scores to predict outcome.

ANIMALS

One hundred and thirty-two client-owned cats.

METHODS

Retrospective study. Bivariate logistic regression analyses were performed to identify variables predictive of 30-day survival. Continuous variables outside the reference range were divided into quartiles to yield quartile-specific odds ratios (OR) for survival. Models were developed incorporating weighting factors assigned to each quartile based on the OR. A predictive score for each model was calculated for each cat by summing all weighting factors. A second, multivariable logistic regression model was created from actual values of the same variables. Receiver operating characteristic curve analyses were performed to determine the models' performance. Models were further tested using a subset of cases not used in initial assessment.

RESULTS

Fifty five of 132 cats (42%) remained dialysis-independent for at least 30 days after discharge, and the remaining 77 cats either died (n = 37, 28%) or were euthanized (n = 40, 30%). The most common etiology was ureteral obstruction (n = 46, 35%). Higher scores were associated with decreased probability of survival (P < .001). Models correctly classified outcomes in 75-77% of the cases and 84-89% of the cases in the subsequent evaluation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Models can provide objective guidance in assessing AKI prognosis and severity, but should be validated in other cohorts of cats.

Renal amyloidosis in dogs: a retrospective study of 91 cases with comparison of the disease between Shar-Pei and non-Shar-Pei dogs

BACKGROUND

Renal amyloidosis (RA) is a progressive and fatal renal disease.

HYPOTHESIS

Clinical and pathologic manifestations of RA differ between Chinese Shar-Pei (CSPs) and non-Shar-Pei (NSPs) dogs.

ANIMALS

91 client-owned dogs.

METHODS

Retrospective review of medical records of dogs with a histological diagnosis of RA. Clinical and clinicopathologic data, hospitalization, complications, and outcome were compared between CSPs and NSPs.

RESULTS

Comorbid diseases were present in 64% of all dogs. CSPs were significantly younger compared to NSPs (median, 4.8 years; range: 3.6-17 versus median: 9.0 years; range: 2.4-11.1; P < .0001). The frequency of hypoalbuminemia, the most common biochemical abnormality, was higher in NSPs compared to CSPs (100% versus 64.7%, respectively; P < .001). Median serum creatinine concentration at presentation was 5.5 mg/dL, and was 3-fold higher in CSPs compared to NSPs (P = .005). Increased urine protein : creatinine ratio was present in 96% of all dogs. Nephrotic syndrome was present in 10% of NSPs but not in CSPs. Glomerular amyloid deposition, present in both CSPs (78.6%) and NSPs (95.6%) was most commonly diffuse, global, and severe. Renal medullar amyloidosis was more common in CSPs (100%) compared to NSPs (49.0%, P = .002), as was extrarenal amyloid deposition. The median survival time of all dogs was 5 days (range: 0-443 days). Serum creatinine concentration was significantly and negatively associated with survival (P = .025).

CONCLUSIONS AND CLINICAL RELEVANCE

The clinical and pathologic manifestations of amyloidosis differ between CSPs and NSPs. The survival time observed herein was unexpectedly low, and argues for early surveillance and management of the underlying predisposing conditions.

A novel clinical scoring system for outcome prediction in dogs with acute kidney injury managed by hemodialysis

BACKGROUND

No reliable tool to predict outcome of acute kidney injury (AKI) exists.

HYPOTHESIS

A statistically derived scoring system can accurately predict outcome in dogs with AKI managed with hemodialysis.

ANIMALS

One hundred and eighty-two client-owned dogs with AKI.

METHODS

Logistic regression analyses were performed initially on clinical variables available on the 1st day of hospitalization for relevance to outcome. Variables with P< or = .1 were considered for further analyses. Continuous variables outside the reference range were divided into quartiles to yield quartile-specific odds ratios (ORs) for survival. Models were developed by incorporating weighting factors assigned to each quartile based on the OR, using either the integer value of the OR (Model A) or the exact OR (Models B or C, when the etiology was known). A predictive score for each model was calculated for each dog by summing all weighting factors. In Model D, actual values for continuous variables were used in a logistic regression model. Receiver-operating curve analyses were performed to assess sensitivities, specificities, and optimal cutoff points for all models.

RESULTS

Higher scores were associated with decreased probability of survival (P < .001). Models A, B, C, and D correctly classified outcomes in 81, 83, 87, and 76% of cases, respectively, and optimal sensitivities/specificities were 77/85, 81/85, 83/90 and 92/61%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

The models allowed outcome prediction that corresponded with actual outcome in our cohort. However, each model should be validated further in independent cohorts. The models may also be useful to assess AKI severity.

Use of capillary electrophoresis to quantitate carbamylated hemoglobin concentrations in dogs with renal failure

OBJECTIVE

To evaluate quantification of the amount of carbamylated hemoglobin (CarbHb), using capillary electrophoresis (CE) and a new dynamic capillary coating system to separate hemoglobin derivatives, and to assess the use of CarbHb amounts to evaluate long-term urea exposure and differential diagnoses of azotemia in dogs.

ANIMALS

8 dogs with renal failure, 2 dogs with diabetes mellitus, and 7 control dogs.

PROCEDURE

Optimal analytic conditions for separation of CarbHb and other hemoglobin derivatives in blood samples obtained from dogs were determined, using a commercial analysis system developed for the detection of glycohemoglobin Hb A1c (GlycHb) in human blood samples. Relative content of hemoglobin derivatives in blood from 10 dogs with renal failure or endocrine diseases were compared with values for 7 dogs without renal or endocrine diseases.

RESULTS

Satisfactory resolution of hemoglobin derivatives was obtained, which permitted identification and quantitation of the amount of CarbHb as a percentage of the total amount of hemoglobin. Normal or increased amounts of GlycHb did not interfere with CarbHb analysis. Dogs with chronic renal failure had considerably higher peak amounts of CarbHb than dogs with acute renal failure, a dog with chronic renal failure that was treated by use of hemodialysis, or dogs without renal disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Amounts of CarbHb in blood samples obtained from dogs can be readily quantified by use of capillary electrophoresis. Assessment of the amount of CarbHb can be used to facilitate evaluation of the cause of azotemia in dogs.

Effects of enalapril versus placebo as a treatment for canine idiopathic glomerulonephritis

A blinded, multicenter, prospective clinical trial assessed the effects of enalapril (EN) versus standard care in dogs with naturally occurring, idiopathic glomerulonephritis (GN). Twenty-nine adult dogs with membranous (n = 16) and membranoproliferative (n = 13) GN were studied. Dogs were randomly assigned to receive either EN (0.5 mg/kg PO q12-24h; n = 16) or placebo (n = 14) for 6 months (1 dog was treated first with the placebo and then with EN). All dogs were treated with low-dose aspirin (0.5-5 mg/kg PO q12-24h) and fed a commercial diet. At baseline, serum creatinine (SrCr), systolic blood pressure (SBP), and glomerular histologic grade were not different between groups, but the urine protein/creatinine ratio (UP/C) was greater in the EN group compared with the placebo group (8.7 +/- 4.4 versus 4.7 +/- 2.3). After 6 months of treatment, the change in UP/C from baseline was significantly different between groups (EN = -4.2 +/- 1.4 versus 1.9 +/- 0.9 in the placebo group). When data were adjusted for changes in SrCr (SrCr X UP/C) a similar significant reduction was noted ( 2.2 +/- 15.2 versus 8.4 +/- 10.1). The change in SBP after 6 months of treatment also was significantly different between groups (EN = -12.8 +/- 27.3 versus 5.9 +/- 21.5 mm Hg in the placebo group). Response to treatment was categorized as improvement (assigned a value of 2), no progression (assigned a value of 1), and progression (assigned a value of 0). Response was significantly better in the EN group (1.4 +/- 0.8) compared with the placebo group (0.3 +/- 0.5). These results suggest that EN treatment is beneficial in dogs with naturally occurring idiopathic GN.

Effect of hemodialysis on plasma amino acid concentrations in healthy dogs

OBJECTIVE

To characterize the effect of maintenance hemodialysis on plasma amino acid concentrations and to quantitate free amino acid losses into the dialysate during hemodialysis in healthy dogs.

ANIMALS

8 healthy adult dogs.

PROCEDURE

Five dogs received hemodialysis treatments 3 times per week for 4 weeks. Plasma amino acid concentrations were evaluated once per week for 4 weeks in each of the 5 dogs prior to hemodialysis (time 0), 90 minutes during hemodialysis, and immediately after hemodialysis (180 minutes). Total free amino acid concentrations and plasma amino acid concentrations (time 0, 90 minutes, and 180 minutes) in the dialysate were evaluated in 3 dogs that received 1 hemodialysis treatment.

RESULTS

Significant time versus week interactions with any plasma amino acid were not detected; however, significant decreases in all plasma amino acid concentrations measured were detected at the midpoint of dialysis (46 +/- 2%) and at the end of each dialysis session (38 +/- 2%). Mean (+/- SEM) total free amino acid loss into the dialysate was 2.7 +/- 0.2 g or 0.12 g/kg of body weight.

CONCLUSIONS AND CLINICAL RELEVANCE

Hemodialysis is associated with significant alterations in plasma amino acid concentrations and loss of free amino acids into the dialysate. Loss of amino acids into the dialysate, coupled with protein calorie malnutrition in uremic patients, may contribute to depletion of amino acid stores.

Treatment and outcome of dogs with leptospirosis: 36 cases (1990-1998)

OBJECTIVE

To characterize serologic and clinical features and outcome of dogs with leptospirosis that were treated conservatively (i.e., medical management alone) or with hemodialysis.

DESIGN

Retrospective study.

ANIMALS

36 dogs with leptospirosis.

PROCEDURE

History; results of physical examinations, ultrasonography, and serologic, hematologic, and serum biochemical analyses; time to resolution of azotemia; and outcome were obtained from medical records. Dogs were treated conservatively (n = 22) or with hemodialysis (14).

RESULTS

Between 1990 and 1998, amount of rainfall was positively correlated with number of cases of leptospirosis identified per year. Serum antibodies against 6 Leptospira serovars were measured, and titers were highest to Leptospira pomona in 16 (44%) dogs, L bratislava in 9 (25%) dogs, and L hardjo in 1 (3%) dog. Eight (22%) dogs had equally high titers to L pomona and L bratislava, 1 (3%) had equally high titers to L grippotyphosa and L canicola, and 1 (3%) had high titers to L grippotyphosa, L pomona, L canicola, and L bratislava. During initial evaluation, all dogs were azotemic. Thirty (83%) dogs survived, including 12 of 14 (86%) dogs treated with hemodialysis and 18 of 22 (82%) treated conservatively. Serum creatinine concentration was similar in both groups after resolution of clinical signs.

CONCLUSIONS AND CLINICAL RELEVANCE

Infection with L pomona and L bratislava was recognized as a cause of leptospirosis in dogs, and resulted in development of acute renal failure with various degrees of azotemia. Prognosis for dogs with mild to moderate azotemia was good with conservative treatment, whereas treatment with hemodialysis appeared to improve prognosis for dogs with severe azotemia.

Evaluation of environmental, nutritional, and host factors in cats with hyperthyroidism

The pathologic changes associated with hyperthyroidism (adenomatous hyperplasia, adenoma of the thyroid gland) have been well characterized in cats, but the pathogenesis of these changes remains unclear. In this research, we undertook a case-control study to search for potential risk factors for this disease. Owners of 379 hyperthyroid and 351 control cats were questioned about their cats' exposure to potential risk factors including breed, demographic factors, medical history, indoor environment, chemicals applied to the cat and environment, and diet. The association between these hypothesized risk factors and outcome of disease was evaluated by conditional logistic regression. Two genetically related cat breeds (ie, Siamese and Himalayan) were found to have diminished risk of developing hyperthyroidism. Cats that used litter had higher risk of developing hyperthyroidism than those that did not. Use of topical ectoparasite preparations was associated with increased risk of developing hyperthyroidism. Compared with cats that did not eat canned food, those that ate commercially prepared canned food had an approximate 2-fold increase in risk of disease. When these 4 variables (breed, use of cat litter, consumption of canned cat food, and use of topical ectoparasite preparations) from the univariate analysis were selected for further study as candidate risk factors and analyzed by multivariate conditional logistic regression, a persistent protective effect of breed (ie, Siamese or Himalayan) was found. In addition, results suggested a 2- to 3-fold increase in risk of developing hyperthyroidism among cats eating a diet composed mostly of canned cat food and a 3-fold increase in risk among those using cat litter. In contrast, the use of commercial flea products did not retain a strong association. The results of this study indicate that further research into dietary and other potentially important environmental factors (eg, cat litter) is warranted.

Plasma amino acid profiles in cats with naturally acquired chronic renal failure

OBJECTIVE

To characterize potential changes in preprandial plasma amino acid concentrations in cats with naturally acquired chronic renal failure (CRF), compared with healthy cats, and to assess potential effects of the severity of renal failure on plasma amino acid concentrations in these cats.

ANIMALS

62 adult cats.

PROCEDURE

Preprandial plasma amino acid concentrations were evaluated in 38 cats with mild, moderate, or severe CRF and in 24 apparently healthy cats. Effects of severity of renal failure, amount of dietary protein, degree of weight loss, appetite, and body condition on plasma amino acid profiles were evaluated.

RESULTS

Cats with various stages of CRF had significantly (P< 0.05) decreased plasma concentrations of o-hydroxyproline, glutamate, proline, glycine, alanine, tyrosine, tryptophan, and arginine, and significantly increased plasma concentrations of asparagine, citrulline, ornithine, 1-methylhistidine, and 3-methylhistidine. Significant (P < 0.05) alterations in amino acid concentrations also were identified when cats with CRF were grouped by appetite or severity of renal disease. Amount of dietary protein, body condition, or degree of weight loss had no significant effect on plasma amino acid concentrations.

CONCLUSIONS

Compared with those in healthy cats, preprandial plasma amino acid profiles in cats with mild, moderate, or severe CRF are abnormal.

CLINICAL RELEVANCE

Despite frequency of altered plasma amino acid concentrations in cats with CRF, the magnitude of these changes is mild and of little clinical relevance. Short-term use of a commercial protein-restricted diet has no deleterious effects on plasma amino acid concentrations.

Gastrin concentrations in plasma of cats with chronic renal failure

OBJECTIVE

To determine the prevalence of hypergastrinemia in cats with naturally developing chronic renal failure (CRF) and the correlation between gastrin concentration in plasma and severity of CRF.

DESIGN

Cohort study.

ANIMALS

30 cats with naturally developing CRF and 12 clinically normal control cats.

PROCEDURE

Gastrin concentrations in plasma were determined by double-antibody radioimmunoassay of blood samples obtained from cats after food was withheld 8 hours. Concentrations were compared, using a nonparametric Kruskal-Wallis ANOVA.

RESULTS

18 cats with CRF had high gastrin concentrations (median, 45 pg/ml; range, < 18 to > 1,333 pg/ml), compared with those for control cats (< 18 pg/ml). Prevalence of hypergastrinemia increased with severity of renal insufficiency. Three of 9 cats with mild CRF, 6 of 11 cats with moderate CRF, and 9 of 10 cats with severe CRF had high gastrin concentrations. Gastrin concentrations were significantly different between control cats and cats with CRF, regardless of disease severity.

CLINICAL IMPLICATIONS

The potential role of high concentrations of gastrin on gastric hyperacidity, uremic gastritis, bleeding from the gastrointestinal tract, and associated clinical signs of hypergastrinemia (e.g., anorexia and vomiting) may justify use of histamine2-receptor antagonists or proton pump inhibitors to suppress gastric acid secretion in cats with CRF that have these clinical signs.

Comparison between the scintigraphic uptake and plasma clearance of 99mTc-diethylenetriaminepentacetic acid (DTPA) for the evaluation of the glomerular filtration rate in dogs

The scintigraphically measured percentage dose uptake of 99mTc-DTPA by the kidneys and the plasma clearance of 99mTc-DTPA have been reported to correlate well with inulin clearance. These two parameters were evaluated in seven dogs with known or suspected naturally occurring renal disease and compared to simultaneously measured renal inulin clearance. Correlation between inulin clearance and the 99mTc-DTPA plasma clearance was better (p = .0016) than the correlation between the percentage DTPA uptake by the kidney. It was concluded that measurement of 99mTc-DTPA plasma clearance is a more accurate method to estimate global glomerular filtration rate (GFR) than the percentage kidney uptake.

Use of recombinant human erythropoietin for management of anemia in dogs and cats with renal failure

OBJECTIVE

To test efficacy and safety of recombinant human erythropoietin (r-HuEPO) administration in dogs and cats with naturally developing chronic renal failure.

DESIGN

Case series.

ANIMALS

6 client-owned dogs and 11 client-owned cats with chronic renal failure.

PROCEDURES

r-HuEPO was administered intravenously or subcutaneously. Erythropoietic effects were monitored by determining CBC, performing cytologic examination of bone marrow aspirates, and measuring serum iron concentration before and during treatment. Development of adverse effects was monitored by performing sequential clinical assessments, CBC, and serum biochemical tests and by measuring indirect blood pressure and anti-r-HuEPO antibody titers.

RESULTS

Administration of r-HuEPO increased RBC and reticulocyte counts, hemoglobin concentration, and Hct comparably in dogs and cats. Assessments of clinical well-being, including appetite, energy, weight gain, alertness, strength, and playfulness, were improved variably. Adverse effects, including anemia, anti-r-HuEPO antibody production, seizures, systemic hypertension, and iron deficiency, were demonstrated inconsistently in dogs and cats.

CLINICAL IMPLICATIONS

Anemia contributes to clinical manifestations of chronic renal failure in dogs and cats. Administration of r-HuEPO has the potential to resolve anemia and improve clinical well-being. However, its administration poses risks of antibody production and adverse effects associated with correction of RBC mass. Use of r-HuEPO in dogs and cats requires conscientious assessment of risks and benefits until homologous forms of erythropoietin are available.

Use of carbamylated hemoglobin concentration to differentiate acute from chronic renal failure in dogs

OBJECTIVE

To determine usefulness of carbamylated hemoglobin (CarHb) concentration for differentiation of acute renal failure (ARF) from chronic renal failure (CRF) in dogs.

SAMPLE POPULATION

Samples from dogs with ARF or CRF and from nonazotemic control dogs.

PROCEDURE

CarHb concentration was determined in heparinized blood samples by measuring the micrograms of valine hydantoin (VH) per gram of hemoglobin (Hb), using a high-performance liquid chromatography assay, in which carbamyl valine is converted to VH via acid hydrolysis.

RESULTS

CarHb concentration was significantly higher in dogs with ARF and CRF, compared with values in control dogs (ARF vs control, P < 0.05; CRF vs control, P < 0.001). Furthermore, CarHb concentration was significantly (P < 0.001) higher in dogs with CRF, compared with that in dogs with ARF. Carbamylated hemoglobin concentration did not correlate with serum urea nitrogen or creatinine concentration. Using a cutoff value of 100 micrograms of VH/g of Hb, the sensitivity and specificity of CarHb concentration for differentiating ARF from CRF was 96.1 and 84.2%, respectively.

CONCLUSIONS

CarHb concentration was useful in the differentiation of ARF from CRF in the dogs of this study.

CLINICAL RELEVANCE

CarHb concentration may be used to increase the accuracy of identifying ARF, so that early, aggressive management can be instituted, thereby increasing the chance of recovery.

Applications and outcome of hemodialysis in cats: a review of 29 cases

Hemodialysis (HD) has been used in the management of renal failure in dogs, but its feasibility has not been reported for uremic cats. Therefore, we investigated the technical possibility, efficacy, and complications of intermittent HD in cats with severe uremia. A total of 160 HD treatments were performed on 29 cats with acute renal failure (ARF) (n = 15), chronic renal failure (CRF) (n = 6), or acute on CRF (n = 8) between November 1993 and June 1996. Hemodialysis treatments were performed with transcutaneous dialysis catheters using a bicarbonate-based delivery system, sodium modeling, and volumetric-controlled ultrafiltration. Presenting serum chemistries (mean +/- SD) for all cats were creatinine, 16.4 +/- 7.5 mg/dL; blood urea nitrogen (BUN), 229 +/- 87 mg/dL; phosphate, 15.4 +/- 5.4 mg/dL; potassium, 6.0 +/- 1.6 mEq/L; and HCO3-, 16.0 +/- 4.4 mEq/L. For intensive HD treatments, pre-HD versus post-HD creatinine changed from 10.3 +/- 4.4 to 1.6 +/- 0.9 mg/dL and BUN from 105 +/- 33 to 8 +/- 10 mg/dL. One or more adverse events occurred during 111 (69%) treatments. Dialysis-related events included hypotension, dialysis dysequilibrium, clotting, and bleeding. Nine of 15 (60%) cats with ARF and 1 cat with CRF recovered sufficiently to survive without ongoing need for HD. For the remaining cats, the proximate causes of death were dialysis related in 9 cats, uremia related in 6 cats, and iatrogenic or unknown in 4 cats. Hemodialysis is technically feasible and effectively controls the biochemical disturbances of uremic cats. It is especially valuable for the management of severe ARF, permitting recovery in a large number of cats refractory to conventional therapy. Technical complications and chronic debility, however, may limit its usefulness for cats with advanced CRF.

Comparison of blood pressure measurements obtained in dogs by use of indirect oscillometry in a veterinary clinic versus at home

OBJECTIVE

To compare blood pressure and heart rate measurements performed in a veterinary clinic to similar measurements performed in a dog's home.

DESIGN

Prospective study.

ANIMALS

14 client-owned, clinically normal dogs.

PROCEDURE

Sequential blood pressure and heart rate measurements were recorded from the metatarsus and metacarpus of conscious dogs by indirect oscillometry. Measurements were performed in the dogs' homes and were repeated in a veterinary clinic. Blood pressures and heart rate were derived from 7 serial estimates over 8 to 10 minutes. Statistical differences between the home and clinic and between recording sites were calculated.

RESULTS

Systolic, diastolic, and mean blood pressure and heart rate measurements obtained from the metatarsus and metacarpus in the dogs' homes were significantly lower than measurements from the metatarsus in the clinic, but were similar to measurements from the metacarpus in the clinic. Significant differences were not found between blood pressure measurements from the metatarsus and metacarpus in the dogs' homes, but systolic and mean blood pressure and heart rate measurements from the metacarpus in the clinic were significantly lower than measurements from the metatarsus. Whereas all dogs had normal blood pressure in their homes, 5 of 14 dogs had transient hypertension (systolic pressure > 165 mm of Hg or diastolic pressure > 95 mm of Hg) in the clinic.

CLINICAL IMPLICATIONS

Blood pressure and heart rate measurements obtained in the clinic initially overestimate comparable measurements in a dog's home. The differences are best explained by transient autonomic responses to the stress of the clinic. Blood pressure must be measured by use of standardized techniques on dogs acclimated to the clinic environment.

Systemic arterial blood pressure and urine protein/creatinine ratio in dogs with hyperadrenocorticism

OBJECTIVE

To determine prevalence and severity of systemic arterial hypertension and proteinuria in dogs with naturally developing hyperadrenocorticism and to determine whether these abnormalities resolve with adequate management of the disease.

DESIGN

Case series and cohort study.

ANIMALS

77 dogs with naturally developing hyper-adrenocorticism examined once; 15 dogs examined before and after treatment.

RESULTS

Among dogs examined only once, hypertension was diagnosed in 21 of 26 dogs with untreated pituitary-dependent hyperadrenocorticism (PDH), 17 of 21 with inadequately controlled PDH, 8 of 16 with well-controlled PDH, 10 of 10 with an untreated adrenocortical tumor, and 0 of 4 that had undergone adrenalectomy because of an adrenocortical tumor. Untreated dogs and dogs with inadequately controlled PDH had significantly higher blood pressures than did other dogs. Proteinuria was documented in 12 of 26 dogs with untreated PDH, 5 of 16 with inadequately controlled PDH, 3 of 14 with well-controlled PDH, 5 of 8 with an untreated adrenocortical tumor, and 1 of 3 that had undergone adrenalectomy. Dogs with untreated PDH and dogs with an untreated adrenocortical tumor had higher urine protein/creatinine ratios than did dogs with well-controlled PDH. Among dogs evaluated before and after treatment, blood pressure and urine protein/creatinine ratio did not change in 8 dogs with inadequately controlled hyperadrenocorticism, but decreased in 7 dogs with well-controlled disease.

CLINICAL IMPLICATIONS

Results suggest that systemic hypertension and proteinuria are common in dogs with untreated hyperadrenocorticism and that successful treatment of hyperadrenocorticism will result in resolution of these abnormalities in many, but not all, dogs.

Role of hemodialysis in the management of dogs and cats with renal failure

Hemodialysis is a technically sophisticated therapy used to remove accumulated uremia toxins and correct the electrolyte, hydrogen ion, and fluid imbalances associated with renal failure. Hemodialysis is indicated when the morbidity or potential mortality from either acute or chronic renal failure cannot be alleviated by conventional therapies. Additionally, it is useful for the rapid removal of excessive fluid loads associated with congestive heart failure or iatrogenic fluid administration and the elimination of dialyzable poisons like ethylene glycol. The requirements for hemodialysis include repeated access to the vasculature, an artificial kidney, and a dialysis delivery system. Technologic advancements in all these requirements make the delivery of hemodialysis feasible, effective, and safe for both dogs and cats. To date, the limitation of facilities offering dialytic therapy has restricted its use in uremic animals but current improvements in dialysis techniques and the increased sophistication of specialty practice make hemodialysis a realistic adjunct to the conservative management of uremia in veterinary medicine.

Clinical and pathological features of protein-losing glomerular disease in the dog: a review of 137 cases (1985-1992)

Medical records of 137 dogs with protein-losing glomerular disease (PLGD) were evaluated. Cases with amyloidosis (23%) were more likely to be azotemic at presentation, with significantly greater proteinuria and hypoalbuminemia than those cases with glomerulonephritis (GN; 77%). The prognosis for all cases was poor, with a median survival time of just 28 days. The most common causes of death in cases with idiopathic disease were chronic renal failure (69.5%) or thromboembolic complications (22.2%). Progression of glomerular disease was unpredictable, with no apparent correlation between survival time and biochemical parameters at presentation.

Case-control study of the association between intraoperative administration of nafcillin and acute postoperative development of azotemia

OBJECTIVE

To describe 7 cases of acute postoperative azotemia in dogs and to examine by use of a case-control study the possible association between this complication and administration of nafcillin.

DESIGN

Retrospective and case-control study.

ANIMALS

7 case dogs and 28 matched control dogs.

PROCEDURE

Cases of acute renal failure or acute renal insufficiency were identified by retrospective study of records of dogs treated between July 1, 1992, and Feb 28, 1995, and from information received from a practitioner. A random sample of records of dogs undergoing invasive procedures between Dec 1, 1992, and Nov 30, 1993, was examined to determine the prevalence of nafcillin use. Each case dog was matched with 4 control dogs, and data were subjected to logistic regression analysis, employing exact conditional inference on the parameter estimates.

RESULTS

Case dogs were between 1 and 9 years old and weighed between 21 and 60 kg. Preoperatively, none of the dogs had a history of renal disease, and BUN concentrations, hematocrit, and plasma protein concentrations were within reference ranges. Postoperatively, each dog became azotemic and had clinical signs consistent with uremia. Hyponatremia was recorded in 6 case dogs. One dog did not respond to treatment and was euthanatized. Two dogs had persistent isosthenuria, and 4 dogs recovered. Nafcillin was used in approximately 502 of 2,184 (23%) dogs that underwent invasive procedures between Dec 1, 1992, and Nov 30, 1993. The use of nafcillin ceased on Nov 30, 1993, and no further cases were recorded in the following 15 months. In the case-control study, the only factor that was significantly associated with the occurrence of acute postoperative azotemia was administration of nafcillin.

CLINICAL IMPLICATIONS

Intraoperative use of nafcillin maybe associated with development of acute postoperative azotemia in dogs.

Decreased urinary catecholamines in a cat with dysautonomia

Feline dysautonomia was diagnosed in a 2-year-old cat with a history of regurgitation, constipation, mydriasis, and dry eyes. The diagnosis of parasympathetic and sympathetic failure was confirmed by abnormal physiologic autonomic function tests and decreased urinary catecholamine measurements. Despite intensive supportive care, the cat failed to improve and was euthanatized 70 days after the onset of illness. Feline dysautonomia is rarely reported in the United States, and the cat had no history of travel to a country where the disease is more prevalent.

Hemodialysis for treatment of oxytetracycline-induced acute renal failure in a neonatal foal

Acute renal failure in a 4-day-old foal secondary to oxytetracycline toxicosis was treated by hemodialysis. Oxytetracycline had been administrered as treatment for forelimb flexor tendon contracture. Conservtive treatment with fluids, furosemide, and dopamine partially alleviated serum electrolyte concentration imbalances, but was ineffective in promoting diuresis or decreasing azotemia. Three hemodialysis treatments over 4 days were administered, after which the clinical appearance of the foal improved, and biochemical and electrolyte values returned to within reference ranges. The nephrotoxic potential of oxytetracycline should be considered prior to its administration. Hemodialysis may be a treatment option in management of acute renal failure in foals that are nonresponsive to conservative medical treatment.

Pathophysiology and management of anemia in chronic progressive renal failure

Hypoproliferative anemia is a predictable and serious complication of progressive renal failure and contributes significantly to the overall morbidity of the uremic state. Until recently, there has been no satisfactory therapy to resolve the anemia. Now the anemia can be explicitly corrected with erythropoietin-replacement therapy, and the clinical debility generally attributable to renal insufficiency can be lessened and retarded. Anemia must no longer be regarded as an intractable consequence of the uremic syndrome and should be managed as conscientiously as the other polysystemic features of uremia.

The Fontan procedure: a historical review

Complete bypass of the right ventricle was first performed successfully and subsequently reported by Fontan and Baudet for patients with tricuspid atresia. By eliminating congenital and surgical shunts, ventricular volume overload and pulmonary hypertension were avoided. A logical extension of its predecessor, the partial right heart bypass procedure introduced by Glenn, the Fontan operation has great application for patients with various forms of univentricular heart. It is one of the historic advances in the surgical treatment of congenital heart disease.

Response to radiation therapy of recurrent lymphangioma in a dog

A recurrent lymphangioma in a 5-year-old Airedale Terrier was treated successfully with cobalt-60 radiation. The neoplasm had been excised twice before being treated with radiation.

Effects of combination cyclosporine/mizoribine immunosuppression on canine renal allograft recipients

Heterotopic renal allografts following bilateral nephrectomies were placed in 21 healthy mongrel dogs. One group of 11 dogs received cyclosporine (5 mg/kg/24 hr, orally), and 1 group of 10 dogs received cyclosporine and mizoribine (5 mg/kg and 3 mg/kg/24 hr, orally). Body weights, blood cell counts, serum chemistry profiles, serum electrolyte levels, urinalysis with cytology and culture, lymphocyte stimulation assays, immunoglobulin levels, whole blood levels of cyclosporine, and serum levels of mizoribine were followed. At the end of each survival period, necropsy and histopathologic examinations were performed. The mean survival time for the cyclosporine group was 12.8 +/- 7 days. The mean survival time for the cyclosporine/mizoribine group was 33.6 +/- 16.4 days, significantly longer (P = .0006) than the cyclosporine group. Death in the cyclosporine/mizoribine group was attributed to the combined effects of renal allograft rejection and development of a mizoribine-dependent enteritis. Serum levels of mizoribine were greater in the last half of the survival period due to compromised renal excretion of the drug. There were no complications due to infection, myelosuppression, or hepatotoxicity. Combination cyclosporine/mizoribine immunosuppression enhanced canine renal allograft survival in this study. Monitoring serum concentrations of mizoribine is imperative to determine toxic (enteritis) levels. Availability of an intravenous form of mizoribine would facilitate immunoregulation during periods of variable intestinal absorption or renal excretion.

Effects of mizoribine on canine renal allograft recipients

Heterotopic renal allograft transplantation and bilateral nephrectomies were performed on 12 mixed-breed dogs. Histoincompatibility was confirmed by serologically defined and lymphocyte-defined antigen testing. Mizoribine (5 mg/kg, q 24 h) was administered orally starting the day of surgery. Body weights, blood cell counts, serum biochemical and electrolyte values, immunoglobulin concentration, and serum mizoribine concentrations were determined. Complete urinalyses, including bacteriologic culturing and lymphocyte stimulation assays were performed. The mean survival time for the allograft recipients was 20 +/- 14 days; significantly longer than nontreated historic controls surviving 8.1 +/- 0.6 days (P = 0.0098). Death was attributed to the combined effects of renal allograft rejection and development of a mizoribine-dependent gastroenteritis. Serum mizoribine concentrations were greater in dogs undergoing rapid allograft rejection because of compromised renal excretion of the drug. This resulted in a rapid onset of gastroenteritis. There were no complications resulting from infection, myelosuppression, or hepatotoxicosis.

Ventricular septal defect due to nonpenetrating chest trauma: use of the intra-aortic balloon pump

Nonpenetrating traumatic ventricular septal defect is rare. A triad of blunt chest trauma, holosystolic precordial murmur, and ECG abnormalities should suggest the diagnosis. Surgical repair, when indicated by progressive failure, rising pulmonary artery pressures, or significant (2:1 or larger) left-to-right shunt, has been shown to be very effective. Optimally, a period of several weeks from the injury should elapse before operative intervention is undertaken. Intra-aortic balloon pump may be helpful to stabilize patients acutely, and, in selected instances, allow delay of surgical repair so that the tissue around the defect may hold sutures more securely.

A practical approach to prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is an infrequent but dread complication, occurring in 1 to 2% of patients both early (less than 60 days) and late postoperatively. Diagnosis is always (99%) possible by two sets of blood cultures, but occasional exogenous causes of bacteremia may cloud the diagnosis, as will culture-negative cases of PVE and skin contaminants. With obvious exogenous sources of bacteremia, achieving sterile blood cultures after eradication of the noncardiac source permits discontinuation of antibiotics after two weeks. When skin contaminants are suspected, withholding antibiotics and obtaining two sets of blood cultures is recommended, because the bacteremia with PVE is continuous. Preventive measures, including perioperative antibiotics, are warranted but will probably not significantly reduce the low incidence of infection already achieved. The major cause of improved survival in recent years is earlier operation (valve rereplacement). This has been demonstrated in the last ten years and is absolutely indicated for major heart failure, ongoing sepsis, fungous etiology, valve obstruction, new-onset heart block, and unstable prosthesis by fluoroscopy.

Repair of pulmonary valve insufficiency using an autologous monocusp

A 3 1/2-year-old boy experienced right ventricular failure approximately two years after an operation for critical pulmonic stenosis. Severe pulmonary and tricuspid valvular insufficiency was documented echocardiographically and at cardiac catheterization. Treatment consisted of a tricuspid valve annuloplasty and creation of an autologous monocusp valve using the anterior wall of the pulmonary artery. The procedure was well tolerated, and early competence of the pulmonary valve was shown intraoperatively by pressure recordings and postoperatively by Doppler echocardiography. However, at recatheterization one year later, there was no evidence that the monocusp valve was functioning. This experience does not support the prior successful application of this technique in animals.

Localization of phosphorus metabolites and sodium ions in the rat kidney

Relative amounts of phosphorus-containing metabolites and sodium ions present in different regions of the in vivo rat kidney were obtained using a surface-coil probe and recently developed NMR rotating-frame methods. During altered physiologic states, changes in distribution of metabolites and sodium ions within the kidney were identified in one-dimensional metabolite maps. This technique may have important applications to disorders commonly found in clinical medicine.

Aortoventriculoplasty in a five-month-old infant: an alternative approach to the treatment of critical aortic stenosis in infancy

A newborn with critical aortic stenosis and anular hypoplasia was treated with an aortic valvotomy using inflow occlusion. Five months later, important valvular insufficiency and residual stenosis necessitated aortic valve replacement. An aortoventriculoplasty using a 19 mm St. Jude Medical Valve was successfully performed with a good hemodynamic response.

Percutaneous nephropyelocentesis and nephropyelostomy in the dog: a description of the technique

Percutaneous nephropyelocentesis or nephropyelostomy was done on 20 anesthetized dogs of both sexes with the aid of fluoroscopy. The upper urinary tracts were visualized by the use of IV radiopaque contrast material and distended by application of an abdominal compression band positioned over the caudal abdomen. Renal pelvic urine was readily obtained by both procedures in each dog. Bloody urine was an infrequent result, and usually occured only after repeated attempts had been made to enter the renal pelvic lumen. To ascertain the degree of renal parenchymal damage caused by passage of the needle and catheter, dogs were euthanatized and necropsied on the 1st, 3rd, 7th, and 14th days after the procedure was done. Repair of the tissue damage was rapid and the lesions were difficult to visualize grossly by the 14th day.