Assessment of changes in hemostatic markers in Cavalier King Charles Spaniels with myxomatous mitral valve disease.
ABSTRACT To evaluate markers of hemostasis and their relationship to the degree of mitral regurgitation (MR) and platelet function in Cavalier King Charles Spaniels (CKCSs) with myxomatous mitral valve disease.
76 clinically healthy CKCSs and 24 control dogs.
All dogs underwent echocardiographic examination; various hemostatic, hematologic, and biochemical variables were evaluated in blood. The CKCSs were allocated to 1 of 3 groups on the basis of MR severity. In 8 control dogs and 8 CKCSs, plasma von Willebrand factor (vWF) multimer analysis was performed.
Compared with control dogs, plasma fibrinogen concentration was higher in all CKCSs and related to left ventricular end diastolic diameter and left atrial-to-aortic root ratio among all CKCSs. The activated partial thromboplastin times and plasma D-dimer concentration were similar among the 4 groups. Plasma vWF concentration was lower in CKCSs with moderate to severe MR, compared with that of CKCSs with no MR and control dogs. There was a relationship between plasma vWF concentration and platelet function in CKCSs but not in control dogs. In 4 CKCSs with moderate to severe MR and low plasma vWF concentration, amounts of vWF high-molecular-weight multimers (HMWMs) were low.
In CKCSs, MR appeared to be associated with a low plasma vWF concentration and likely a loss of vWF HMWMs (possibly through their destruction via shear stress to the blood). The importance of the changes in plasma fibrinogen concentration and the thromboembolic risk in dogs with MR remain to be investigated.
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ABSTRACT: To review the mechanisms of platelet activation and options for diagnosing and treating platelet hyperactivity in relation to thrombosis in dogs and cats. Prospective, retrospective, and review articles, as well as textbook chapters in both human and veterinary medicine. Articles were primarily, but not exclusively, retrieved via Medline. In people, platelets are known to play a key role in the development of arterial thrombosis in numerous disease states and antiplatelet drugs are the cornerstone in the treatment of acute events and for prevention in patients at risk. For many years, aspirin was used as the sole antiplatelet drug in people, but the introduction of adenosine diphosphate receptor antagonists and integrin α(IIb) β(3) inhibitors has significantly improved outcome in selective groups of patients. The understanding of platelet activation in disease states has increased dramatically over the past decade. Simultaneously, a host of new methods for evaluating platelet function have been developed, which enable primarily researchers, but also clinicians to monitor the activity of platelets. Many of these methods have been validated for research purposes, but few have found their way to the clinics. Not a single correctly randomized clinical trial has been carried out with any antiplatelet drug for any indication in dogs or cats, and consequently, treatment is empiric and largely based on expert opinion or data from experimental studies. The pathogenesis of thromboembolic disease is complex and multifactorial and the role of hyperactive platelets in this etiology remains to be clarified in most of the diseases associated with thrombosis in dogs and cats. Until efficacy data from well-designed studies are available, antithrombotic therapy should consist of close monitoring, good supportive care, and judicious empirical use of antiplatelet agents.02/2012; 22(1):42-58. DOI:10.1111/j.1476-4431.2011.00708.x
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ABSTRACT: Mitral valve prolapse (MVP) represents a common degenerative disease, often requiring surgery. If untreated, MVP with considerable valve incompetence can lead to cardiovascular and systemic complications causing substantial morbidity and mortality. In contrast with the wide knowledge concerning clinical and physiological features, currently available data regarding its molecular bases are very limited. We review current knowledge concerning MVP biological mechanisms, focusing on specific aspects of haemostasis, platelet function, oxidative stress, extracellular matrix remodeling and genomics. In particular, available evidence supports the role played by tissue remodeling processes in determining MVP onset and progression. Moreover, even if a consistent although controversial perturbation of haemostatic system and alterations of the oxidative stress equilibrium have been proposed to influence disease development, it is unknown whether these changes precede or follow MVP occurrence. Consequently, the complete knowledge of all the biochemical pathways involved are far from complete. In addition, changes in the regulation pattern of adrenergic and renin-angiotensin-aldosterone systems have been described in MVP syndrome, a condition characterized by the association of MVP with other peculiar neurological and general symptoms, but it is unknown whether these abnormalities are shared by "traditional" MVP. In conclusion, MVP is probably a multi-factorial process, and many aspects still need to be clarified. As surgery can only correct the damaged valve but not the underlying mechanisms, a more complete knowledge of the involved molecular pathways is necessary, as it may allow the discovery of targeted therapeutic strategies aimed at modifying or slackening MVP natural course in the early phases.International journal of cardiology 12/2010; 151(2):129-35. DOI:10.1016/j.ijcard.2010.11.004 · 6.18 Impact Factor
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ABSTRACT: Veterinarians involved in Greyhound rescue have anecdotally observed that 10–15% of Greyhounds bleed profusely after simple surgical procedures. In most patients, platelet counts and hemostasis profiles are normal; therefore, it is possible that these dogs have platelet dysfunction. The PFA-100a is a novel point-of-care platelet function analyzer that has recently been evaluated as a rapid method to assess platelet function in dogs. The objectives of this study were to characterize platelet function in a group of healthy Greyhounds by means of the PFA-100. Blood samples were collected from the jugular vein from 30 healthy Greyhounds. CBC, biochemical profile, PFA-100 assay with collagen/epinephrine (COL-EPI) and collagen/ adenosindiphosphate (COL-ADP), plasma von Willebrand factor antigen concentration (vWF: Ag), and vWF collagen-binding assay (vWF:CBA) were performed. PFA-100 closure times (CTs) with COL/ADP ranged from 63 to 92 seconds (mean ± SD, 74.7 ± 7.9 seconds) and with COL/EPI from 87 to 238 seconds (138 ± 41 seconds); vWF:Ag ranged from 22 to 120% (87.52 ± 25.5%) and vWF:CBA ranged from 36 to 102% (77.4 ± 17.3%); and platelet counts ranged from 147 to 265 ± 109/L (194.6 ± 31.64 ± 109/L). Greyhound CTs were significantly shorter than CTs in a mixed population of 50 healthy non-Greyhound dogs, in which the COL/ADP CTs ranged from 61 to 172 seconds (mean ± SD, 87 ± 21.6 seconds), and the COL/ EPI CTs ranged from 81 to 300 seconds (mean ± SD, 183 ± 67.6 seconds; P= 0.005 for COL/ADP CT; P= 0.001 for COL/ EPI CT). Also, platelet counts were significantly lower (P= 0.001) and packed cell volume was significantly higher (P= 0.001) in the Greyhound than in the non-Greyhound group. The PFA-100 is a reproducible method that can be used in the clinical setting to assess platelet function in Greyhounds; however, normal CTs in healthy Greyhounds are shorter than in other breeds. The results obtained in this study will be used to screen for abnormal platelet function in Greyhounds with postoperative bleeding.Journal of Veterinary Internal Medicine 02/2006; 20(2):365 - 370. DOI:10.1111/j.1939-1676.2006.tb02869.x · 2.22 Impact Factor