Serial changes in blood pressure and neurohormone levels after the onset of lacunar stroke

Outcome after Stroke upon Awakening

Background:

An estimated 20-25% of all strokes occur during sleep and these patients wake up with their deficits. This study evaluated outcomes among patients who woke up with stroke compared to those who were awake at stroke onset.

Methods:

Using data from the Registry of the Canadian Stroke Network Phases 1 and 2, we compared demographics, clinical data and six-month outcomes between patients with stroke-on-awakening versus stroke-while-awake. Strokes of all types (ischemic stroke, transient ischemic attack, intracerebral hemorrhage and subarachnoid hemorrhage) were included. Standard descriptive statistics, multivariable logistic regression and general linear modeling were applied to the data to compare variables.

Results:

Among 2,585 stroke patients, 349 (13.5%) woke up with stroke and 2,236 (86.5%) did not. Patients with stroke-on-awakening were more likely to have higher blood pressure and to suffer ischemic stroke, but stroke severity, measured by level of consciousness, did not differ. Mortality both at discharge and at six-month follow-up did not differ between the two cohorts. However, patients with stroke-on-awakening were less likely to return home, and their median Stroke Impact Scale-16 scores were 7.0 points lower compared to those with stroke-while-awake.

Conclusions:

There are minor demographic and clinical differences between patients with stroke-on-awakening and stroke-while-awake. Functional outcomes are slightly worse among patients with stroke-on-awakening, an effect which was driven by poor outcomes among patients with subarachnoid hemorrhage.

Plasma B-type natriuretic peptide level in patients with acute cerebral infarction according to infarction subtype and infarction volume

BACKGROUND

Plasma B-type natriuretic peptide (BNP) is used as a diagnostic marker of cardiovascular diseases. BNP is secreted mainly from the myocardium and has been detected by immunoreactivity in brain and cerebral arteries. The aim of our study was to investigate plasma BNP in patients with acute cerebral infarction according to infarction subtype and infarction volume.

METHODS

We studied 141 patients with acute cerebral infarction, classified as large artery atherosclerosis (LAA), cardioembolism (CE), or small vessel disease (SA) according to the Trial of Org 10172 in Acute Stroke Treatment classification. Plasma BNP level was measured in patients and 61 healthy controls. We analyzed various clinical and laboratory variables of patients according to plasma BNP level.

RESULTS

Compared to controls, the patients had higher plasma BNP (11.9 ± 11.7 pg/mL versus 124.6 ± 228.8 pg/mL, p <0.01). The highest quartile BNP group was associated with advanced age, female gender, current non-smoker, atrial fibrillation, heart failure, CE group, increased white blood cell counts, increased high sensitivity C-reactive protein, increased left atrium size, decreased left ventricular ejection fraction, increased initial National Institute of Health Stroke Scale, and increased infarction volume. According to multiple regression analysis, CE group, female gender, and infarction volume were independently associated with plasma BNP. Plasma BNP level showed statistically significant differences among LAA (n = 71), CE (n = 50), and SA (n = 20) groups (p <0.001), and the expression decreased in order of CE (253.8 ± 337.1 pg/mL), LAA (61.6 ± 78.8 pg/mL), and SA (25.3 ± 24.8 pg/mL). Increased plasma BNP correlated with increased infarction volume (r = 0.42, p <0.001).

CONCLUSIONS

Plasma BNP may be helpful for prediction of etiologic classification of acute cerebral infarction and infarction volume.

Early changes in physiological variables after stroke

Several aspects of physiology, notably blood pressure, body temperature, blood glucose, and blood oxygen saturation, may be altered after an ischemic stroke and intracerebral hemorrhage. Generally, blood pressure and temperature rise acutely after a stroke, before returning to normal. Blood glucose and oxygen levels may be abnormal in individuals, but they do not follow a set pattern. Several aspects of these physiological alterations remain unclear, including their principal determinants - whether they genuinely affect prognosis (as opposed to merely representing underlying processes such as inflammation or a stress response), whether these effects are adaptive or maladaptive, whether the effects are specific to certain subgroups (e.g. lacunar stroke) and whether modifying physiology also modifies its prognostic effect. Hypertension and hyperglycemia may be helpful or harmful, depending on the perfusion status after an ischemic stroke; the therapeutic response to their lowering may be correspondingly variable. Hypothermia may provide benefits, in addition to preventing harm through protection from hyperthermia. Hypoxia is harmful, but normobaric hyperoxia is unhelpful or even harmful in normoxic patients. Hyperbaric hyperoxia, however, may be beneficial, though this remains unproven. The above-mentioned uncertainties necessitate generally conservative measures for physiology management, although there are notably specific recommendations for thrombolysis-eligible patients. Stroke unit care is associated with better outcome, possibly through better management of poststroke physiology. Stroke units can also facilitate research to clarify the relationship between physiology and prognosis, and to subsequently clarify management guidelines.

Loss of circadian rhythm of blood pressure following acute stroke

BACKGROUND

Epidemiology of acute stroke in developing countries differs from that in the developed world, for example, the age at stroke, risk factors, subtypes of stroke and prognosis. Hypertension remains a dominant risk factor and prognostic indicator in patients with stroke in all communities. The risk of stroke is directly related to elevations of blood pressure. A number of clinical studies have shown that the control of hypertension leads to a reduction in the incidence of stroke in a community. However there is still considerable controversy surrounds the changes in blood pressure in various subtypes of strokes and problem of management of elevated BP after stroke. We studied the circadian rhythm of blood pressure in patients following acute stroke.

METHODS

To study the circadian rhythm of blood pressure, fifty consecutive patients with an acute stroke who were admitted to medical emergency within 120 hours of onset were included in the study. After a detailed history and clinical examination, a continuous blood pressure monitor (Spacelab 90207) was attached on the side ipsilateral to intracranial lesion (unaffected arm). The blood pressure was recorded for 24 hours at 15 minutes interval during daytime (6.00 am-6.00 pm) and 20 minutes interval overnight (6 pm to 6 am).

RESULTS

Risk factors for stroke in 50 patients included hypertension in 31(62%), diabetes mellitus in 4 (8%), smoking in 13 (26%) and previous history of transient ischemic attack in 7 (14%) patients. Mean systolic pressure and diastolic pressure at admission were higher in patients with hemorrhagic stroke -29 patients (177 +/- 24 mmHg and 105 +/- 19 mmHg respectively) compared to patients with ischemic strokes-21 patients (150 +/- 36 mm Hg and 89 +/- 18 mm Hg respectively, p value <0.01 in both comparisons). The normal diurnal variation in blood pressure (night time dipping of more than 10%) was abolished in 44 (88%) of patients. Out of 44 nondippers, 29 patients showed reverse dipping i.e. rise of BP during night time compared to day time levels. None of the risk factors, clinical or laboratory variables, type of stroke or blood pressure changes differed significantly between these two groups.

CONCLUSIONS

Therefore, we showed a pathologically reduced or abolished circadian BP variation after stroke. Absence of normal dipping results in a higher 24 hour blood pressure load and may have more target organ damage than those with normal diurnal variation of blood pressure.

Hypercortisolemia in acute stroke is related to the inflammatory response

Hypercortisolemia is thought to be a marker of the stress response following stroke. The aim of this study was to investigate the prevalence and prognostic significance of hypercortisolemia. The circadian variation of cortisol level and the relationship between serum cortisol levels and other stress, inflammatory, and haemostatic markers were also investigated. Seventy consecutive patients with their first ischemic stroke and 24 age- and sex-matched controls were included in the study. Serum cortisol levels (at 6:00 AM, 10:00 AM, 6:00 PM, and 10:00 PM), 24-h urine catecholamine excretion, beta-thromboglobulin levels, and other standard biochemical and haematological parameters were measured on the first day of hospitalisation and in control subjects. Outcome measures used the Barthel Index at Day 30, as well as 30- and 90-day mortality rates. Hypercortisolemia, defined as at least two of the four measurements above the normal range of serum cortisol levels (i.e. >618 nmol/l from the morning samples and >460 nmol/l from the evening samples) was found in 25 (35.7%) of the acute stroke patients and in 3 (12.5%) of the controls (p<0.05). Hypercortisolemia was associated with older age, greater severity of neurological deficit, larger ischemic lesions on CT, and worse prognoses (p<0.05). The study did not find a correlation between serum cortisol levels and other markers of the stress response such as catecholamines excretion and glucose levels. A significant correlation between serum cortisol levels and some markers of the inflammatory response, such as fever, fibrinogen level, white blood cell (WBC) count, and beta-thromboglobulin level, was established in stroke patients. Prognostic significance of hypercortisolemia in acute stroke patients seems to be related to the inflammatory response rather than to the stress response.

Melatonin rhythms in stroke patients

Very little is known regarding melatonin's circadian rhythm in stroke patients. We compared urinary-sulfatoxymelatonin (6-SMT), its major metabolite, in 11 extensive cortical and seven deep or lacunar stroke patients on day 3 or 4 and day 10 post-stroke. Urinary 6-SMT and creatinine measured every 4 h for 24 h starting at 06:00 h significantly fluctuated during the day in both types of stroke and did not differ between day 3 or 4 and day 10 post-stroke. However, in extensive cortical lesions, a delay in the 6-SMT excretion was observed in the first post-stroke days compared to day 10. We conclude that circadian oscillator is preserved in extensive cortical as well as in deep and lacunar strokes. Extensive cortical stroke might delay the melatonin surge during the first post-stroke days.