Red Blood Cell Distribution Width, Hematology, and Serum Biochemistry in Dogs with Echocardiographically Estimated Precapillary and Postcapillary Pulmonary Arterial Hypertension

Abstract

BackgroundRed blood cell distribution width (RDW) is a quantitative measurement of anisocytosis. RDW has prognostic value in humans with different cardiovascular and systemic disorders, but few studies have investigated this biomarker in dogs.ObjectivesTo compare the RDW in dogs with precapillary and postcapillary pulmonary hypertension (PH) and a control population of dogs and to correlate RDW with demographic, echocardiographic, and laboratory variables.AnimalsOne hundred and twenty‐seven client‐owned dogs including 19 healthy dogs, 82 dogs with myxomatous mitral valve disease (50 dogs without PH and 32 dogs with postcapillary PH), and 26 dogs with precapillary PH.MethodsProspective study. Dogs were allocated to groups according to clinical and echocardiographic evaluation. RDW and selected laboratory and echocardiographic variables were compared among dog groups. Associations between RDW and demographic, laboratory, and echocardiographic variables were analyzed using correlation and multiple regression analysis.ResultsMedian RDW in dogs with precapillary PH (13.8%, interquartile range 13.2–14.9%) and postcapillary PH (13.7, 13.2–14.7%) was significantly increased compared to healthy dogs (13.3, 12.3–13.7%; P < .05 for both comparisons), but only dogs with severe PH had significantly increased RDW compared to dogs without PH (P < .05). Peak tricuspid regurgitation pressure gradient was significantly associated with increased RDW (rho = 0.263, P = .007). Serum urea concentration, hematocrit, age, and white blood cell number were significantly associated with RDW in the multivariate analysis.Conclusions and Clinical ImportanceUnderlying pathophysiologic processes associated with PH instead of severity of PH are likely responsible for increased RDW in dogs with PH.

Evaluation of frequency and intensity of asymptomatic anisocytosis in the Japanese dog breeds Shiba, Akita, and Hokkaido

“…The RDW was correlated negatively with haematocrit and haemoglobin concentration. No correlation between RDW and MCV was noted by Mazzotta et al (2016), in contrast to the previous studies by other authors (Fig. 2), both in humans and dogs (Hampole et al 2009;Guglielmini et al 2013;Swann et al 2014).…”

“…Red cell distribution width (RDW) as an anisocytosis indicator is a quantitative measure of the range of variation of the circulating red blood cells (Neiger et al 2002;Hodges and Christopher 2011;Montagnana et al 2012;Mazzotta et al 2016). It is a routinely measured indicator by haematology analysers (Lippi and Plebani 2014).…”

ACVIM consensus statement guidelines for the diagnosis, classification, treatment, and monitoring of pulmonary hypertension in dogs

“…f In the peer-reviewed veterinary literature, many studies refer to "chronic respiratory/pulmonary disease" or "idiopathic" respiratory disease, or "chronic tracheobronchial disease" without definitive documentation of the specific underlying disorder. 35,[40][41][42]66,85,149 Other listed "definitive" diagnoses may be published without ruling out disease mimics in an exhaustive fashion (eg, thoracic radiography alone can be definitive for collapsing trachea but nondefinitive for bronchomalacia or fibrotic lung disease). Without a criterion standard definitive confirmation (eg, bronchoscopy for bronchomalacia or lung biopsy for pulmonary fibrosis), many of these respiratory diseases are likely inadequately characterized.…”

“…Additionally, disorders which are not clearly documented or are undocumented to cause PH in the dog include pharyngeal collapse, 150 laryngeal collapse, laryngeal paralysis, and epiglottic retroversion. g Although "chronic bronchitis" has been listed as a diagnosis in some canine reports, 18,85 this syndrome alone in the dog is unlikely to cause PH. The term chronic obstructive pulmonary disease (COPD) used in humans encompasses underlying and overlapping conditions such as chronic bronchitis and emphysema.…”

Retrospective evaluation of serum/plasma iron, red blood cell distribution width, and nucleated red blood cells in dogs with acute trauma (2009–2015): 129 cases

“…Other novel predictive laboratory variables potentially linked to the iron‐erythropoiesis axis include the red blood cell distribution width (RDW) and the presence of nucleated red blood cells (nRBCs) in peripheral blood, termed rubricytosis/metarubricytosis or normoblastemia. The RDW increases as the coefficient of variation of erythrocyte size increases, and often accompanies regenerative anemias, iron deficiency states, and some types of cardiac disease . In addition, RDW has been demonstrated to be a strong independent predictor of mortality in a variety of diseases in people, ranging from ICU patients in general to trauma patients specifically, but has so far received little attention in the veterinary literature .…”