Retrospective evaluation of systemic hypertension in dogs with nonassociative (primary) immune-mediated hemolytic anemia (December 2016 to April 2019): 26 cases

Objective To report the prevalence of arterial hypertension in a population of dogs with nonassociative immune-mediated hemolytic anemia (IMHA) on presentation and during hospitalization. To determine the relationships of systolic blood pressure (SBP) with mortality and a prognostic indicator, the canine hemolytic anemia objective score. Design Retrospective observational study (December 2016 to April 2019). Setting University teaching hospital. Animals Twenty-six clinical dogs presenting to the ICU with nonassociative (primary) IMHA and a control group of 23 clinical dogs with idiopathic epilepsy hospitalized in the ICU for seizure treatment or monitoring. Interventions None. Measurements and Main Results Hypertension was defined as SBP >= 160 mm Hg and severe hypertension as SBP >= 180 mm Hg. Mean SBP was significantly increased in IMHA dogs (161 mm Hg, SD = 21) compared to ICU control dogs (138 mm Hg, SD = 14; P < 0.005). Hypertension was present in 13 of 26 (50.0%) dogs across the period of hospitalization and was severe in three of 26 (11.5%). During at least 1 day of hospitalization, 18 of 26 (69.2%) dogs were hypertensive and eight of 26 (34.6%) were severely hypertensive. Hypertension was not associated with short-term mortality or canine hemolytic anemia objective score. Conclusions In this retrospective study, hypertension was more prevalent in dogs with nonassociative IMHA than a control population of ICU-hospitalized dogs. An association between autoimmune conditions and hypertension has been previously reported in people but not within a canine population. Hypertension in dogs may have an inflammatory or autoimmune etiology. SBP should be monitored closely in canine IMHA, in case antihypertensive treatment is required.