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- Author or Editor: E. Christopher Orton x
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Abstract
Objective—To determine factors associated with long-term survival in dogs treated surgically for patent ductus arteriosus (PDA).
Design—Retrospective case series.
Animals—52 dogs treated surgically for left-to-right shunting PDA.
Procedure—Data pertaining to age, breed, sex, body weight, clinical examination findings, type and duration of medical treatment, results of thoracic radiography and echocardiography, and surgical and postoperative complications were collected from records. Follow-up information was obtained from medical records or telephone interviews with owners or referring veterinarians.
Results—22 dogs had mitral valve regurgitation. Mean weight and age were not significantly different between dogs with or without mitral valve regurgitation. Twenty-four (46.2%) dogs had clinical signs related to cardiac insufficiency. Left atrial dilatation was observed in 56.3% of dogs that were radiographed. Sonographic imaging was used to diagnose left atrial dilatation in 23 dogs and left ventricular dilatation in 25 dogs. The 1- and 2-year survival rates were 92% and 87%, respectively. Diagnosis of mitral valve regurgitation before surgery was not associated with the probability of survival. Age, weight, lethargy, preoperative treatment with angiotensin-converting enzyme inhibitors, and right atrial dilatation on radiographs at the time of surgery were negatively associated with probability of survival.
Conclusions and Clinical Relevance—Surgical treatment of PDA was curative in young dogs without clinical signs of heart failure. Surgical correction of PDA should be recommended as early as possible after diagnosis, and mitral valve regurgitation is not a contraindication for surgery. (J Am Vet Med Assoc 2005;227:1794–1799)
Abstract
Objective—To determine whether logarithmic and polynomial models are superior to simple linear models for predicting reference values for M-mode echocardiographic variables in dogs with a wide range of body weights.
Animals—69 apparently healthy adult male and female dogs of various breeds, ages (range, 1 to 12 years; median, 3.5 years), and body weights (range, 3.9 to 97.7 kg; median, 25.4 kg).
Procedure—Echocardiographic M-mode measurements of the interventricular septum, left ventricular dimension (LVD), left ventricular wall, aorta, and left atrium were obtained. Simple linear, second-order polynomial, third-order polynomial, and logarithmic regression models were determined by use of the least-squares method to describe the relationship between M-mode measurements and body weight. Differences in adjusted R 2 values of logarithmic and polynomial models were tested for significance of contribution, compared with the simple linear model.
Results—Significant differences in adjusted R2 were found when comparing simple linear with logarithmic or polynomial models for LVD-diastole, LVD-systole, aorta, and left atrium. Differences in adjusted R2 between second-order polynomial, third-order polynomial, and logarithmic models were not significant for any M-mode measurement.
Conclusions and Clinical Relevance—In this study, logarithmic or second-order polynomial models predicted reference values of M-mode measurements for size of the cardiac chambers better than simple linear models for dogs with a wide range of body weights. Logarithmic and polynomial models were not superior to simple linear models for M-mode measurements of cardiac wall thickness. (Am J Vet Res 2002;63:994–999)
Abstract
Objective—To describe surgical techniques for and assess outcome of treatment of mitral regurgitation in dogs.
Design—Uncontrolled prospective study.
Animals—18 dogs with naturally occurring mitral regurgitation.
Procedure—All dogs weighed > 5 kg (11 lb) and had severe mitral regurgitation, congestive heart failure (CHF), and no serious noncardiac disease. Left ventricular volume indices, left atrial size, and degree of mitral regurgitation were determined echocardiographically before and after surgery. Repair techniques included circumferential annuloplasty, placement of artificial chordae, chordal fenestration and papillary muscle splitting, and edge-to-edge repair. Factors predictive for surgery survival and resolution of CHF were determined.
Results—12 dogs survived surgery. Factors predictive for surgery survival included weight > 10 kg (22 lb) and CHF of less than 6 months' duration. In 9 dogs, CHF resolved for a median period of 1 year (range, 4 months to 3 years) after surgery. One dog had stable CHF at 12 months. One dog died as a result of progressive CHF; another was euthanatized for a noncardiac reason. Left ventricular diastolic volume index was 226.9 ± 117.7 cm3/m2 before surgery and 134.9 ± 70.4 cm3/m2 at 6 months after surgery (n = 10). Factors predictive for resolution of CHF included left ventricular diastolic volume index < 250 cm3/m2 and systolic volume index < 70 cm3/m2.
Conclusion and Clinical Relevance—Mitral valve repair may resolve CHF in dogs with severe mitral regurgitation, particularly in dogs that weigh > 10 kg and are treated within 6 months of the onset of CHF. (J Am Vet Med Assoc 2004;224:1941–1945)
Objective
To determine factors associated with disease-free interval and survival time for dogs with pericardial effusion.
Design
Retrospective study.
Animals
46 dogs.
Procedure
Signalment, history, results of physical examination, electrocardiography, echocardiography, and thoracic radiography; disease-free interval; and survival time were obtained from medical records or telephone conversations with owners and referring veterinarians.
Results
Dogs that had ascites at the time of the initial physical examination were significantly less likely, and dogs that had evidence of pulmonary metastases on thoracic radiographs or that had echocardiographic evidence of a right atrial mass were significantly more likely, to have died of pericardial effusion or the underlying cause of effusion than were dogs that did not. Median survival time was 15.3 months for dogs with idiopathic pericardial effusion, 16 days for dogs with hemangiosarcoma, and 13.6 months for dogs with mesothelioma. Dogs that had a nonspecific extracardiac mass and underwent pericardiectomy were significantly less likely to have had recurrence of signs than were dogs that did not. However, dogs with mesothelioma or hemangiosarcoma that underwent pericardiectomy did not have a significantly different risk of recurrence of signs or survival time, compared with dogs that did not.
Clinical Implications
Results suggest that pericardiectomy will not affect risk of recurrence or survival time in dogs with pericardial effusion secondary to hemangiosarcoma or mesothelioma. However, pericardiectomy is still needed to differentiate dogs with neoplastic pericardial effusion from dogs with idiopathic pericardial effusion. (J Am Vet Med Assoc 1998;212: 1276–1280)
SUMMARY
Vascular medial thickening is a prominent finding in people and animals with refractory neonatal pulmonary hypertension. Smooth muscle cells are capable of 2 distinct growth responses in vivo: hypertrophy or hyperplasia. Hypertrophic smooth muscle cells may undergo dna synthesis without cell division, leading to a polyploid state. To better understand the nature of smooth muscle cell growth in healthy and pulmonary hypertensive neonatal calves, we measured incorporation of the thymidine analog bromodeoxyuridine (BrdUrd) and total dna content in medial cells from control (pulmonary arterial pressure = 32 ± 2 mm of Hg) and hypobaric hypoxia-exposed (pulmonary arterial pressure = 120 ± 7 mm of Hg) calves. Labeling of medial cells with BrdUrd measured by flow cytometry was increased (P < 0.02) in pulmonary arteries of hypoxia-exposed calves (n = 5), compared with control calves (n = 5). Immunohistochemical localization of BrdUrd indicated that BrdUrd labeling of large elastic pulmonary arteries from hypoxia-exposed calves was increased almost exclusively in the outer half of the medial wall. Increased BrdUrd labeling of muscular pulmonary arteries from hypoxia exposed calves was observed in the arterial media and adventitia, and tended to exit in clusters. Analysis of dna content by flow cytometry indicated a decrease (P < 0.05) in percentage of tetraploid medial cells in pulmonary arteries from hypoxia-exposed calves, compared with control calves. Bivariate analysis for BrdUrd labeling and dna content of cells from the pulmonary arteries of hypoxia-exposed calves indicated a subpopulation of diploid cells with positive BrdUrd labeling, suggestive of dna synthesis and subsequent cell division. Results are suggestive of smooth muscle cell hyperplasia in the vascular media of hypoxia-exposed calves.
