The Hydration Influence on the Risk of Stroke (THIRST) Study

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.

Dysphagia, nutrition, and hydration in ischemic stroke patients at admission and discharge from acute care

Dysphagia may predispose stroke patients toward undernutrition and hydration. These comorbidities increase patient risks for reduced functional outcome and short-term mortality. Despite this impact, available information on relationships among dysphagia, nutrition, and hydration status in acute stroke is limited and conflicted. This study evaluated nutrition and hydration status in ischemic stroke patients with versus without clinically significant dysphagia at admission and at discharge from acute care. Sixty-seven patients admitted to the stroke unit in a tertiary-care hospital provided data for this study. On the day of hospital admission and upon discharge or at 7 days post admission, serum biochemical measures were obtained for nutrition (prealbumin) and hydration status (BUN/Cr). Clinical evaluation for dysphagia, nutrition status, and stroke severity were completed an average of 1.4 days following hospital admission. Dysphagia was identified in 37 % of the cohort. At admission 32 % of patients demonstrated malnutrition based on prealbumin levels and 53 % demonstrated evidence of dehydration based on BUN/Cr levels. No differences in nutrition status were attributed to dysphagia. Patients with dysphagia demonstrated significantly higher BUN/Cr levels (greater dehydration) than patients without dysphagia at admission and at discharge. Dehydration at both admission and discharge was associated with dysphagia, clinical nutrition status, and stroke severity. Results of this study support prior results indicating that dysphagia is not associated with poor nutrition status during the first week post stroke. Dehydration status is associated with dysphagia during this period. The results have implications for future confirmatory research and for clinical management of dysphagia in the acute stroke period.

Mild dehydration affects mood in healthy young women

Limited information is available regarding the effects of mild dehydration on cognitive function. Therefore, mild dehydration was produced by intermittent moderate exercise without hyperthermia and its effects on cognitive function of women were investigated. Twenty-five females (age 23.0 ± 0.6 y) participated in three 8-h, placebo-controlled experiments involving a different hydration state each day: exercise-induced dehydration with no diuretic (DN), exercise-induced dehydration plus diuretic (DD; furosemide, 40 mg), and euhydration (EU). Cognitive performance, mood, and symptoms of dehydration were assessed during each experiment, 3 times at rest and during each of 3 exercise sessions. The DN and DD trials in which a volunteer attained a ≥1% level of dehydration were pooled and compared to that volunteer's equivalent EU trials. Mean dehydration achieved during these DN and DD trials was -1.36 ± 0.16% of body mass. Significant adverse effects of dehydration were present at rest and during exercise for vigor-activity, fatigue-inertia, and total mood disturbance scores of the Profile of Mood States and for task difficulty, concentration, and headache as assessed by questionnaire. Most aspects of cognitive performance were not affected by dehydration. Serum osmolality, a marker of hydration, was greater in the mean of the dehydrated trials in which a ≥1% level of dehydration was achieved (P = 0.006) compared to EU. In conclusion, degraded mood, increased perception of task difficulty, lower concentration, and headache symptoms resulted from 1.36% dehydration in females. Increased emphasis on optimal hydration is warranted, especially during and after moderate exercise.

Reduced hydration status characterized by disproportionate elevation of blood urea nitrogen to serum creatinine among the patients with cerebral infarction

The significance of fluid metabolism among the patients with cerebral infarction has barely mentioned in the literature despite the several reports suggesting the potential risk of reduced hydration status for the development of cerebral infarction. The aim of the this study is to explore the validity of the presumable relationship between hydration status and cerebral infarction. Ninety-seven patients with cerebral infarction from April 1, 2008 to March 31, 2009 were retrospectively investigated, and their hydration status were evaluated by using several clinical parameters such as a blood urea nitrogen to serum creatinine (BUN/Cr) ratio of >25 and plasma osmolality. Subjects with active infection, congestive heart failure, hepatic failure, gastrointestinal bleeding, or a malignancy were excluded since these conditions should modulate the absolute value of BUN/Cr ratio without a change in hydration status. Twenty-eight patients (29%) were considered as having reduced hydration status. The BUN/Cr ratio decreased significantly after the initiation of medical support (median 21.3; IR: 18.1-24.6), including oral or parenteral fluid supplementation, in comparison to the values at the time of patient admission (median 30.0; IR: 26.8-40.7; p<0.0001). Similar decreases were also observed in the hematocrit, hemoglobin, and plasma osmolality. The group considered to have reduced hydration status had a significantly higher prevalence of cardioembolic stroke than the other subjects. The hydration status may be a contributing factor to subtypes of cerebral infarction. Whether our findings are also the case with overall patients with cerebral infarction should be evaluated in greater detail.

Neglect is more common and severe at extreme hemoglobin levels in right hemispheric stroke

BACKGROUND AND PURPOSE

Anemia is 1 potential mechanism by which the brain receives inadequate oxygenation. The purpose of this study was to determine in acute stroke patients whether lower hemoglobin values were associated with worse hemispatial neglect.

METHODS

In 203 subjects, neglect testing batteries were administered within 24 hours of admission for acute right hemispheric stroke. We analyzed the error rate on each test as well as "any neglect" (z score >or=2 on any of 3 selected tests compared with normal controls), as predicted by hemoglobin level, with adjustment for infarct size, National Institutes of Health Stroke Scale score, age, and sex.

RESULTS

The association between hemoglobin and neglect varied on the basis of hemoglobin level. At lower hemoglobin levels (<12 g/dL), each 1-point higher hemoglobin value was protective (adjusted odds ratio=0.56; 95% CI, 0.35 to 0.89) from having "any neglect." However, for a hemoglobin value >14 g/dL, each 1-point higher hemoglobin value was associated with higher odds of having neglect (adjusted odds ratio=1.67; 95% CI, 1.09 to 2.57). Similar relations were found for predicted error rate on the horizontal line bisection, line cancellation, and copy Ogden scene neglect tests. These relations seemed to be more pronounced in individuals who had a diffusion/perfusion mismatch.

CONCLUSIONS

Lower and higher hemoglobin levels were each associated with increased odds of neglect and with worse severity of neglect, independent of stroke size and severity. Higher hemoglobin values may represent dehydration or hyperviscosity. The importance of the extremes of hemoglobin in identifying individuals at risk for worse functional consequences of stroke warrants further study.

The risk of acute radiocontrast-mediated kidney injury following endovascular therapy for acute ischemic stroke is low

BACKGROUND AND PURPOSE

Endovascular therapy is an alternative for the treatment of AIS resulting from large intracranial arterial occlusions that depends on the use of iodinated RCM. The risk of RCM-mediated AKI following endovascular therapy for AIS may be different from that following coronary interventions because patients may not have identical risk factors.

MATERIALS AND METHODS

All consecutive patients with large-vessel AIS undergoing endovascular therapy were prospectively recorded. We recorded the baseline kidney function, and RCM-AKI was assessed according to the AKIN criteria at 48 hours after RCM administration. We compared the rate of RCM-AKI 48 hours after the procedure and sought to determine whether any preexisting factors increased the risk of RCM-AKI.

RESULTS

We identified 99 patients meeting inclusion criteria. The average volume of contrast was 189 ± 71 mL, and the average creatinine change was -4.6% at 48 hours postangiography. There were 3 patients with RCM-AKI. Although all 3 patients died as a result of their strokes, return to baseline creatinine levels occurred before death. There was a trend toward higher rates of premorbid diabetes mellitus, chronic renal insufficiency, preadmission statin and NSAID use, and a higher serum creatinine level on admission for the RCM-AKI group. The volume of procedural contrast was similar between groups (those with and those without RCM-AKI) (P = .5).

CONCLUSIONS

In this small study, the rate of RCM-AKI following endovascular intervention for AIS was very low. A much larger study is required to determine its true incidence.