Systolic blood pressure reduction and risk of acute renal injury in patients with intracerebral hemorrhage

Background: Aggressive systolic blood pressure reduction may precipitate acute renal injury because of underlying hypertensive nephropathy in patients with intracerebral hemorrhage. The study's objective was to determine the rate and determinants of acute renal injury during acute hospitalization among subjects with intracerebral hemorrhage using a post hoc analysis of a multicenter prospective study.

Methods: Subjects with intracerebral hemorrhage and elevated systolic blood pressure of 170 mm Hg or greater who presented within 6 hours of symptom onset and underwent treatment of acute hypertensive response and fluid management as per study and local protocols, respectively. Acute renal injury was defined post hoc using the criteria used in Acute Kidney Injury Network classifications within 72 hours of admission. Descriptive statistics and standard statistical tests were used to characterize and evaluate the effect of systolic blood pressure reduction parameters (relative to initial systolic blood pressure) and average maximum hourly dose of nicardipine on the occurrence of acute renal injury.

Results: A total of 60 subjects were recruited (57% were men; mean age of 62.0 ± 15.1 years). Five subjects (9%) had stage I acute renal injury according to the Acute Kidney Injury Network criteria. None of the subjects had stage II or III acute renal injury. The serum creatinine course for the first 3 days suggested that the peak elevation of creatinine was seen at 18, 30, 57, 58, and 71 hours after baseline measurements in these 5 subjects, all of which except for the first one were beyond the protocol-specified treatment period. The incidences of neurologic deterioration and symptomatic hematoma expansion were significantly greater in the subjects with stage I renal impairment. The systolic blood pressure reduction parameters (in particular, the area under the curve depicting the 24-hour systolic blood pressure summary statistic) and the higher average maximum hourly nicardipine dose were strongly associated with stage I renal impairment.

Conclusions: Although acute renal injury is infrequent and mild among subjects with intracerebral hemorrhage undergoing systolic blood pressure reduction, a trend in association between systolic blood pressure reduction and renal impairment was observed in this small study. Therefore, it is important to carefully monitor the renal function when administering treatment to reduce systolic blood pressure in patients with intracerebral hemorrhage.