This prospective cohort study followed 45 dogs with spontaneous chronic renal failure (CRF) to determine whether high systolic blood pressure (SBP) was associated with increased risk of uremic crisis, death, or decline in renal function. Dogs were assigned to 1 of 3 groups on the basis of high, intermediate, or low initial SBP. Reciprocal serum creatinine concentration was used as an estimate of renal function. Kaplan-Meier and Cox proportional hazards methods were used to estimate the association of SBP with the development of uremic crisis and death. Dogs with high SBP exhibited a greater decrease in renal function, and systolic blood pressure remained high in 10 of 11 dogs treated with antihypertensive drugs. Dogs in the high SBP group (14 dogs) were more likely to develop a uremic crisis and die than were dogs in the other 2 groups, and risks increased significantly as SBP increased. Further study is required to determine whether there is a cause-and-effect relationship between high SBP and progressive renal injury, as well as to identify the risks and benefits of antihypertensive drug treatment.
COMMENTARY: As we continue to learn more about the significance of elevated blood pressure in dogs and cats, more practitioners are beginning to use this tool in practice. Anytime we have a parameter that can help in predicting the outcome of a case, we can better advise clients and better manage a case. There are too few of these tools in veterinary medicine, so any promise is welcome.
COMMENTARY: This study confirms anecdotal reports that a rapid decrease in glomerular filtration rate can occur in dogs with concurrent chronic renal failure (CRF) and severe hypertension. Duration of survival was shortened in patients with extreme hypertension compared to normotensive dogs. In addition, this form of hypertension may be difficult to control with currently used antihypertensive drugs. Blood pressure measurement may provide information that would affect prognosis in dogs with CRF.
Association between initial systolic blood pressure and risk of developing a uremic crisis or of dying in dogs with chronic renal failure. Jacob F, Polzin DJ, Osborne CA, et al. JAVMA 222:322-329, 2003.
