Acute hypertension in intracerebral hemorrhage: pathophysiology and treatment

Prevalence of Risk Factors in Patients With Spontaneous Intracerebral Hemorrhage in Damascus_Syria: A Retrospective Cross-Sectional Study

Objectives

This study aims to determine the prevalence of risk factors among patients with spontaneous intracerebral hemorrhage in Syrian society.

Methods

This study is a retrospective cross-sectional study, patients' data were collected from four hospitals. Cross-tabulation tables and the χ 2 test were used to show the relationship between gender/age and the prevalence of risk factors, demonstrate statistical significance, and calculate p value.

Results

From a total of 194 patients included in the study, there were 123 males, accounting for 63.4% of the patients, while there were 71 females, accounting for 36.6%. The most common risk factor among intracerebral hemorrhage patients was hypertension at 44.8% of the total patients, followed by antithrombotic use at 25.8%, smoking at 19.1%, diabetes at 15.5%, and hematological diseases making up 9.3% of the patients, whereas in age groups under 10 years, various hematological diseases were the most prevalent risk factors at 42.5%, followed by prematurity at 27.5%, and hyaline membrane disease at 15%. The study showed no statistically significant differences in the distribution of risk factors between males and females except for smoking. However, the results revealed a significant difference in the distribution of risk factors according to age for Smoking, hypertension, antithrombotic use, diabetes, arteriovenous malformation, hyaline membrane disease, hematological diseases, and prematurity (p < 0.05).

Conclusion

The study showed that hypertension and antithrombotic use are the most important risk factors for intracerebral hemorrhage, so controlling arterial pressure and periodic tests such as platelet count/PT/PTT are gold roles in preventing intracerebral hemorrhage.

Prognostic Significance of Serum NLRP3 in Spontaneous Intracerebral Hemorrhage

Background

Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) is involved in secondary brain injury after acute intracerebral hemorrhage (ICH). The objective of this study was to determine its ability to predict early neurological deterioration (END) and 3-month neurological outcome after ICH.

Methods

In this prospective cohort study, serum NLRP3 levels were measured in 128 patients with sICH and 100 healthy controls. National institute of health stroke scale (NIHSS) scores and hematoma volumes were recorded. Post-ICH END and 3-month poor outcome (modified Rankin Scale (mRS) scores of 3-6) were documented. The results were assessed using multivariate analysis.

Results

Serum NLRP3 levels in sICH patients increased significantly as compared to controls (P<0.001). Serum NLRP3 levels were independently correlated with hematoma volumes (β=0.046; 95% confidence interval (CI), 0.020-0.072; P=0.001) and NIHSS scores (β=0.071; 95% CI, 0.004-0.139; P=0.039), independently forecasted END (OR=1.268; 95% CI, 0.892-1.801; P=0.036) and poor prognosis at post-ICH 3 months (OR=1.448; 95% CI, 1.006-2.085; P=0.046), and were predictive of them with areas under receiver operating characteristic curve at 0.788 (95% CI, 0.706-0.855) and 0.805 (95% CI, 0.725-0.870) separately. Serum NLRP3 levels, along with the two independent predictors, that are NIHSS scores and hematoma volumes, are combined to establish prediction models of END and poor prognosis. The models worked well by applying a series of statistical methods.

Conclusion

Increased serum NLRP3 levels after ICH are independently associated with bleeding severity, END and adverse outcomes of patients, meaning that serum NLRP3 may be a potential prognostic biomarker of sICH.

Serum Ionized Calcium as a Prognostic Biomarker in Type B Aortic Dissection After Endovascular Treatment

OBJECTIVE

Lower serum ionized calcium (iCa2+) was reported to be associated with a higher risk of adverse events in patients with cardiovascular diseases. This study aimed to investigate the associations between preoperative serum iCa2+ and outcomes of type B aortic dissection (TBAD) patients receiving thoracic endovascular aortic repair (TEVAR).

METHODS

Between January 2016 and December 2019, 491 TBAD patients received TEVAR in a single center. Patients with acute or subacute TBAD were included. Serum iCa2+ (pH 7.4) was obtained from the arterial blood gas analysis before TEVAR. The study population was grouped into the hi-Ca group (1.11 mmol/L ≤ iCa2+ < 1.35 mmol/L) and lo-Ca group (iCa2+ < 1.11 mmol/L). The primary outcomes were all-cause mortality. The secondary outcomes were any major adverse clinical events (MACEs), which included all-cause mortality and aortic-related severe complications. To eliminate bias, 1:1 propensity score matching (PSM) was conducted.

RESULTS

Overall, 396 TBAD patients were included in this study. In the total population, there were 119 (30.1%) patients in the lo-Ca group. After PSM, 77 matched pairs were obtained for further analysis. In the matched population, the 30-day mortality and 30-day MACEs between the two groups presented significant differences (p=0.023 and 0.029, respectively). At 5 years, cumulative incidences of mortality (log-rank p<0.001) and MACEs (log-rank p=0.016) were significantly higher in the lo-Ca group than that of the hi-Ca group. Multivariate cox regression analysis indicated that lower preoperative iCa2+ (hazard ratio for per 0.1 mmol/L decrease, 2.191; 95% confidence interval, 1.487-3.228, p<0.001) was an independent risk factor for 5-year mortality after PSM.

CONCLUSIONS

Lower preoperative serum iCa2+ might have an association with 5-year mortality in TBAD patients after TEVAR. Serum iCa2+ monitoring in this population may facilitate the identification of critical conditions.

CLINICAL IMPACT

Our present study found that the cutoff value of preoperative serum iCa2+ 1.11 mmol/L, which is slightly lower than the lower limit of the normal range of 1.15-1.35 mmol/L, worked relatively well for discerning the high-risk and low-risk TBAD patients at 5 years. Serum iCa2+ monitoring in TBAD patients receiving TEVAR may facilitate the identification of critical conditions.

Cerebral Hemorrhage: Pathophysiology, Treatment, and Future Directions

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high morbidity and mortality. This review article focuses on the epidemiology, cause, mechanisms of injury, current treatment strategies, and future research directions of ICH. Incidence of hemorrhagic stroke has increased worldwide over the past 40 years, with shifts in the cause over time as hypertension management has improved and anticoagulant use has increased. Preclinical and clinical trials have elucidated the underlying ICH cause and mechanisms of injury from ICH including the complex interaction between edema, inflammation, iron-induced injury, and oxidative stress. Several trials have investigated optimal medical and surgical management of ICH without clear improvement in survival and functional outcomes. Ongoing research into novel approaches for ICH management provide hope for reducing the devastating effect of this disease in the future. Areas of promise in ICH therapy include prognostic biomarkers and primary prevention based on disease pathobiology, ultra-early hemostatic therapy, minimally invasive surgery, and perihematomal protection against inflammatory brain injury.

Longitudinal, Quantitative, Multimodal MRI Evaluation of Patients With Intracerebral Hemorrhage Over the First Year

In most patients with intracerebral hemorrhage (ICH), the hematoma and perihematomal area decrease over the subsequent months but patients continue to exhibit neurological impairments. In this serial imaging study, we characterized microstructural and neurophysiological changes in the ICH-affected brain tissues and collected the National Institute of Health Stroke Scale (NIHSS) and modified Rankin Score (mRS), two clinical stroke scale scores. Twelve ICH patients were serially imaged on a 3T MRI at 1, 3, and 12 months (M) after injury. The hematoma and perihematomal volume masks were created and segmented using FLAIR imaging at 1 month which were applied to compute the susceptibilities (χ), fractional anisotropy (FA), mean diffusivity (MD), and cerebral blood flow (CBF) in the same tissues over time and in the matching contralesional tissues. At 3 M, there was a significant (p < 0.001) reduction in hematoma and perihematomal volumes. At 1 M, the χ, FA, and CBF were decreased in the perihematomal tissues as compared to the contralateral side, whereas MD increased. In the hematomal tissues, the χ increased whereas FA, MD, and CBF decreased as compared to the contralesional area at 1 M. Temporally, CBF in the hematoma and perihematomal tissues remained significantly (p < 0.05) lower compared with the contralesional areas whereas MD in the hematoma and χ in the perihematomal area increased. The NIHSS and mRS significantly correlated with hematoma and perihematomal volume but not with microstructural integrity. Our serial imaging studies provide new information on the long-term changes within the brain after ICH and our findings may have clinical significance that warrants future studies.

Hypertensive Crisis in Acute Cerebrovascular Diseases Presenting at the Emergency Department: A Narrative Review

Hypertensive crisis, defined as an increase in systolic blood pressure >179 mmHg or diastolic blood pressure >109 mmHg, typically causes end-organ damage; the brain is an elective and early target, among others. The strong relationship between arterial hypertension and cerebrovascular diseases is supported by extensive evidence, with hypertension being the main modifiable risk factor for both ischemic and hemorrhagic stroke, especially when it is uncontrolled or rapidly increasing. However, despite the large amount of data on the preventive strategies and therapeutic measures that can be adopted, the management of high BP in patients with acute cerebrovascular diseases presenting at the emergency department is still an area of debate. Overall, the outcome of stroke patients with high blood pressure values basically depends on the occurrence of hypertensive emergency or hypertensive urgency, the treatment regimen adopted, the drug dosages and their timing, and certain stroke features. In this narrative review, we provide a timely update on the current treatment, debated issues, and future directions related to hypertensive crisis in patients referred to the emergency department because of an acute cerebrovascular event. This will also focus greater attention on the management of certain stroke-related, time-dependent interventions, such as intravenous thrombolysis and mechanic thrombectomy.

Hypertensive Crisis in Acute Cerebrovascular Diseases Presenting at the Emergency Department: A Narrative Review

Hypertensive crisis, defined as an increase in systolic blood pressure >179 mmHg or diastolic blood pressure >109 mmHg, typically causes end-organ damage; the brain is an elective and early target, among others. The strong relationship between arterial hypertension and cerebrovascular diseases is supported by extensive evidence, with hypertension being the main modifiable risk factor for both ischemic and hemorrhagic stroke, especially when it is uncontrolled or rapidly increasing. However, despite the large amount of data on the preventive strategies and therapeutic measures that can be adopted, the management of high BP in patients with acute cerebrovascular diseases presenting at the emergency department is still an area of debate. Overall, the outcome of stroke patients with high blood pressure values basically depends on the occurrence of hypertensive emergency or hypertensive urgency, the treatment regimen adopted, the drug dosages and their timing, and certain stroke features. In this narrative review, we provide a timely update on the current treatment, debated issues, and future directions related to hypertensive crisis in patients referred to the emergency department because of an acute cerebrovascular event. This will also focus greater attention on the management of certain stroke-related, time-dependent interventions, such as intravenous thrombolysis and mechanic thrombectomy.

The collagenase model of intracerebral hemorrhage in awake, freely moving animals: The effects of isoflurane

Intracerebral hemorrhage (ICH) is a devastating stroke often modelled in rats. Isoflurane anesthetic, commonly used in preclinical research, affects general physiology (e.g., blood pressure) and electrophysiology (e.g., burst suppression) in many ways. These physiological changes may detract from the clinical relevance of the model. Here, we revised the standard collagenase model to produce an ICH in rats without anesthetic. Guide cannulas were implanted stereotaxically under anesthetic. After 3 days of recovery, collagenase was infused through an internal cannula into the striatum of animals randomly assigned to the non-anesthetized or isoflurane group. We assessed whether isoflurane affected hematoma volume, core temperature, movement activity, pain, blood pressure, and seizure activity. With a small ICH, there was a hematoma volume increased from 8.6 (±3.3, 95% confidence interval) µL in anesthetized rats to 13.2 (±3.1) µL in non-anesthetized rats (P = 0.008), but with a larger ICH, hematoma volumes were similar. Isoflurane decreased temperature by 1.3 °C (±0.16 °C, P < 0.001) for 2 h and caused a 35.1 (±1.7) mmHg group difference in blood pressure (P < 0.007) for 12 m. Blood glucose increased twofold after isoflurane procedures (P < 0.001). Pain, as assessed with the rat grimace scale, did not differ between groups. Seizure incidence rate (62.5%) in non-anesthetized ICH rats was similar to historic amounts (61.3%). In conclusion, isoflurane appears to have some significant and injury size-dependent effects on the collagenase model. Thus, when anesthetic effects are a known concern, the use of the standardized cannula infusion approach is scientifically and ethically acceptable.

The role of pericytes in brain disorders: from the periphery to the brain

It is becoming increasingly apparent that disorders of the brain microvasculature contribute to many neurological disorders. In recent years it has become clear that a major player in these events is the capillary pericyte which, in the brain, is now known to control the blood-brain barrier, regulate blood flow, influence immune cell entry and be crucial for angiogenesis. In this review we consider the under-explored possibility that peripheral diseases which affect the microvasculature, such as hypertension, kidney disease and diabetes, produce central nervous system (CNS) dysfunction by mechanisms affecting capillary pericytes within the CNS. We highlight how cellular messengers produced peripherally can act via signalling pathways within CNS pericytes to reshape blood vessels, restrict blood flow or compromise blood-brain barrier function, thus causing neuronal dysfunction. Increased understanding of how renin-angiotensin, Rho-kinase and PDGFRβ signalling affect CNS pericytes may suggest novel therapeutic approaches to reducing the CNS effects of peripheral disorders.

A Narrative Review of Cardiovascular Abnormalities After Spontaneous Intracerebral Hemorrhage

BACKGROUND

The recommended cardiac workup of patients with spontaneous intracerebral hemorrhage (ICH) includes an electrocardiogram (ECG) and cardiac troponin. However, abnormalities in other cardiovascular domains may occur. We reviewed the literature to examine the spectrum of observed cardiovascular abnormalities in patients with ICH.

METHODS

A narrative review of cardiovascular abnormalities in ECG, cardiac biomarkers, echocardiogram, and hemodynamic domains was conducted on patients with ICH.

RESULTS

We searched PubMed for articles using MeSH Terms "heart," "cardiac," hypertension," "hypotension," "blood pressure," "electro," "echocardio," "troponin," "beta natriuretic peptide," "adverse events," "arrhythmi," "donor," "ICH," "intracerebral hemorrhage." Using Covidence software, 670 articles were screened for title and abstracts, 482 articles for full-text review, and 310 extracted. A total of 161 articles met inclusion and exclusion criteria, and, included in the manuscript. Cardiovascular abnormalities reported after ICH include electrocardiographic abnormalities (56% to 81%) in form of prolonged QT interval (19% to 67%), and ST-T changes (19% to 41%), elevation in cardiac troponin (>0.04 ng/mL), and beta-natriuretic peptide (BNP) (>156.6 pg/mL, up to 78%), echocardiographic abnormalities in form of regional wall motion abnormalities (14%) and reduced ejection fraction. Location and volume of ICH affect the prevalence of cardiovascular abnormalities. Prolonged QT interval, elevated troponin-I, and BNP associated with increased in-hospital mortality after ICH. Blood pressure control after ICH aims to preserve cerebral perfusion pressure and maintain systolic blood pressure between 140 and 179 mm Hg, and avoid intensive blood pressure reduction (110 to 140 mm Hg). The recipients of ICH donor hearts especially those with reduced ejection fraction experience increased early mortality and graft rejection.

CONCLUSIONS

Various cardiovascular abnormalities are common after spontaneous ICH. The workup of patients with spontaneous ICH should involve 12-lead ECG, cardiac troponin-I, as well as BNP, and echocardiogram to evaluate for heart failure. Blood pressure control with preservation of cerebral perfusion pressure is a cornerstone of hemodynamic management after ICH. The perioperative implications of hemodynamic perturbations after ICH warrant urgent further examination.

Association of angiotensin-converting enzyme G2350A gene polymorphisms with hypertension among patients with intracerebral haemorrhage

OBJECTIVES

To evaluate the correlation of angiotensin-converting enzyme (ACE) G2350A gene polymorphisms with hypertension, brain hematoma volume (BHV), level of consciousness, and disease outcome among intracerebral haemorrhage (ICH) patients.

METHODS

A cross-sectional study was conducted in Zainoel Abidin General Hospital from May 2016 to June 2017. Polymerase chain reaction was used to genotype ACE G2350A gene polymorphisms. BHV was assessed using the ABC/2 volume estimation formula. Level of consciousness was assessed by Glasgow coma scale (GCS). Disease outcome was assessed using Glasgow outcome scale (GOS). Association tests for ACE G2350A genotype in the context of hypertension status, BHV, GCS score, and GOS score in subjects with ICH was analysed by multiple logistic regression.

RESULTS

A total of 75 ICH patients were included in the study. Of those, 59 patients exhibited hypertension, 24 patients had BHV ≥60 cm3, 16 patients possessed GCS scores ≤8, and 72 patients had GOS scores of 1-3. Our analysis determined that the A allele of the ACE G2350A gene polymorphism was significantly associated with a 3.6-fold increase in hypertension; however, this polymorphism was not associated with BHV, level of consciousness, and disease outcome among ICH patients.

CONCLUSION

The A allele of the ACE G2350A gene polymorphisms is associated with hypertension among ICH patients.

Secondary Bleeding During Acute Experimental Intracerebral Hemorrhage

Background and Purpose- Mechanisms contributing to acute hematoma growth in intracerebral hemorrhage are not well understood. Neuropathological studies suggest that the initial hematoma may create mass effect that can tear vessels in the vicinity by shearing, causing further bleeding and hematoma growth. Methods- To test this in mice, we simulated initial intracerebral hemorrhage by intrastriatal injection of a liquid polymer that coagulates upon contact with tissue and measured the presence and volume of bleeding secondary to the mass effect using Hemoglobin ELISA 15 minutes after injection. Results- Secondary hemorrhage occurred in a volume-dependent (4, 7.5, or 15 μL of polymer) and rate-dependent (0.05, 0.5, or 5 μL/s) manner. Anticoagulation (warfarin or dabigatran) exacerbated the secondary hemorrhage volume. In a second model of hematoma expansion, we confirmed that intrastriatal whole blood injection (15 μL, 0.5 μL/s) also caused secondary bleeding, using acute Evans blue extravasation as a surrogate. Anticoagulation once again exacerbated secondary hemorrhage after intrastriatal whole blood injection. Secondary hemorrhage directly and significantly correlated with arterial blood pressures in both nonanticoagulated and anticoagulated mice, when modulated by phenylephrine or labetalol. Conclusions- Our study provides the first proof of concept for secondary vessel rupture and bleeding as a potential mechanism for intracerebral hematoma growth.

Failure of bumetanide to improve outcome after intracerebral hemorrhage in rat

After intracerebral hemorrhage (ICH), brain edema commonly occurs and can cause death. Along with edema, there are significant alterations in the concentrations of key ions such as sodium, potassium, and chloride, which are essential to brain function. NKCC1, a cation-chloride cotransporter, is upregulated after brain damage, such as traumatic injury and ischemic stroke. NKCC1 brings sodium and chloride into the cell, possibly worsening ion dyshomeostasis. Bumetanide, a specific NKCC1 antagonist, blocks the transport of chloride into cells, and thus should attenuate the increases in chloride, which should lessen brain edema and improve neuronal functioning post-ICH, as with other injuries. We used the collagenase model of ICH to test whether bumetanide treatment for three days (vs. vehicle) would improve outcome. We gave bumetanide beginning at two hours or seven days post-ICH and measured behavioural outcome, edema, and brain ion content after treatment. There was some evidence for a minor reduction in edema after early dosing, but this did not improve behaviour or lessen injury. Contrary to our hypothesis, bumetanide did not normalize ion concentrations after late dosing. Bumetanide did not improve behavioural outcome or affect lesion volume. After ICH, bumetanide is safe to use in rats but does not improve functional outcome in the majority of animals.

American Heart Association High Blood Pressure Protocol 2017: A Literature Review

Hypertension is the most prevalent clinical symptom arising from various cardiovascular disorders. Likewise, it is considered a precursor or sequelae to the development of acute coronary artery disease and congestive heath failure (CHF). Hypertension has been considered a cardinal criterion to determine cardiovascular function. According to the World Health Organization (WHO) global observatory data, hypertension causes more than 7.5 million deaths a year, about 12.8% of the total human mortality. Similarly, the Center for Disease Control (CDC) states that 35% of the American adults have been estimated to have a persistently high blood pressure, which makes it about one in every three adults. Hypertension is a modifiable symptom that can be managed through pharmacological and non-pharmacological methods and standard protocols set forth by the American Heart Association (AHA). With new findings from various clinical trials related to the management of hypertension, new developments and recommendations have been made to update the previously established protocols for hypertension. This article aims to discuss and dissect the modern updates of hypertension management as comprehensively elaborated in the 2017 Hypertension Clinical Practice Guidelines.

Efficacy and safety of intravenous nimodipine administration for treatment of hypertension in patients with intracerebral hemorrhage

BACKGROUND

Nicardipine (NC) is the most commonly used antihypertensive drug in neurological patients with hypertension. Although nimodipine (NM) is widely used to treat cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage, trials exploring its antihypertensive effect after intravenous administration in subjects with intracerebral hemorrhage (ICH) are scarce.

METHODS

A retrospective study was carried out to compare the safety and efficacy of NC and NM administered intravenously in patients with ICH. Therapeutic responses were assessed by achievement of goal blood pressure (BP); use of additional medications for BP control; proportion of time spent within goal; variability in BP; time to goal BP; number of dose adjustments; variability in ICH volume, Glasgow Coma Scale score, and intracranial pressure; and drug-related complications.

RESULTS

A total of 87 patients were eligible for analysis (n=46 [NC]; n=41 [NM]), and baseline characteristics between groups were similar. Both agents were effective in achieving goal BP during infusion, with 93.5% and 87.8% patients in the NC and NM groups achieving goal, respectively. Fewer additional medications were needed to control BP in the NC group. BP variability was similar and no differences were observed in the mean time to goal BP and mean numbers of dose adjustments between both groups. Interestingly, intracranial pressure declined (P=0.048) during NC administration but increased (P=0.066) after NM treatment. Finally, the incidences of hematoma expansion, neurological deterioration, and adverse drug events were similar in both groups.

CONCLUSION

NM is effective and safe for BP control in patients with ICH.

Management of acute hypertensive response in patients with intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is intra-parenchymal bleeding that may lead to localized hematoma formation. The hematoma can enlarge over a period of time, and directly contribute to neurological deterioration and death. Several studies have shown a relationship between acute hypertensive response and poor prognosis among patients with ICH; however, it is somewhat unclear whether hematomal expansion, is a cause or a result of elevated blood pressure (BP). Current AHA guidelines state MAP should be maintained <130 mmHg and systolic blood pressure (SBP) <180 mmHg. Two major clinical trials demonstrating tolerability and safety of aggressive BP management to BP <140 mmHg in the acute phase of ICH were the ATACH (2004-2008) and INTERACT (2005-2007) trials. ATACH II and INTERACT 2 trials are currently being conducted to demonstrate the efficacy of SBP reduction as the next step to the ATACH and INTERACT pilot trials.

Intracerebral hemorrhage: a review of coagulation function

Intracerebral hemorrhage (ICH) is associated with a higher mortality rate among stroke subtypes. The amount of hematoma at baseline and subsequent expansion are considered strong independent markers for determining poor clinical outcome. Even though reduction in blood pressure to prevent and control the amount of bleeding in ICH has received considerable amount of attention, the impact of coagulopathy and platelet dysfunction, on the bleeding diathesis has not been extensively investigated. With the increasing use of antiplatelets and/or anticoagulants, given the aging population, a deeper understanding of the interactions between ICH and hemostatic mechanisms is essential to help minimize the risk of a catastrophic coagulopathy-related ICH. In this review article, etiology and risk factors associated with coagulopathy-related ICH are discussed. An overview of coagulation abnormalities, hemostatic agents, and blood biomarkers pertaining to ICH is included.

Blood pressure lowering and stroke

Hypertension is the most prevalent of the modifiable risk factors for stroke. The benefits of blood pressure (BP) lowering on primary and secondary prevention of stroke are undeniable. Despite this, BP control in hypertensive individuals and patients with prior cerebrovascular events is suboptimal. Noncompliance, inappropriate antihypertensive usage and under-utilization of medications contribute significantly to inadequate BP control. Recently, elegantly designed studies that assessed the preventive role of BP lowering in patients with cerebrovascular disease have helped clarify management issues in terms of BP targets and effective antihypertensive regimens. Current evidence suggests that BP targets for primary and secondary prevention are suboptimal and need reassessment. The effect of BP modulation in acute stroke is still not completely understood. Although the thresholds for BP treatment in acute stroke have been recommended, BP targets are as yet ill-defined. The available evidence supports early lowering of blood pressure following stroke. This review discusses the impact of blood pressure on stroke incidence and outcomes, outlines the recommendations for blood pressure lowering in stroke and delineates questions that still need to be addressed.

Temporal MRI assessment of intracerebral hemorrhage in rats

BACKGROUND AND PURPOSE

MRI was used to evaluate the effects of experimental intracerebral hemorrhage (ICH) on brain tissue injury and recovery.

METHODS

Primary ICH was induced in rats (n=6) by direct infusion of autologous blood into the striatum. The evolution of ICH damage was assessed by MRI estimates of T(2) and T(1sat) relaxation times, cerebral blood flow, vascular permeability, and susceptibility-weighted imaging before surgery (baseline) and at 2 hours and 1, 7, and 14 days post-ICH. Behavioral testing was done before and at 1, 7, and 14 days post-ICH. Animals were euthanized for histology at 14 days.

RESULTS

The MRI appearance of the hemorrhage and surrounding regions changed in a consistent manner over time. Two primary regions of interest were identified based on T(2) values. These included a core, corresponding to the bulk of the hemorrhage, and an adjacent rim; both varied with time. The core was associated with significantly lower cerebral blood flow values at all post-ICH time points, whereas cerebral blood flow varied in the rim. Increases in vascular permeability were noted at 1, 7, and 14 days. Changes in T(1sat) were similar to those of T(2). MRI and histological estimates of tissue loss were well correlated and showed approximately 9% hemispheric tissue loss.

CONCLUSIONS

Although the cerebral blood flow changes observed with this ICH model may not exactly mimic the clinical situation, our results suggest that the evolution of ICH injury can be accurately characterized with MRI. These methods may be useful to evaluate therapeutic interventions after experimental ICH and eventually in humans.

Management of warfarin-related intracerebral hemorrhage

Warfarin-related intracerebral hemorrhage (WICH) is a medical and neurosurgical emergency with a 1-month mortality of approximately 50%. Warfarin is commonly is used in patients with atrial fibrillation to prevent ischemic stroke and to prevent progression of deep vein thrombosis to pulmonary embolism. Owing to the ageing population, and increased incidence of atrial fibrillation with age and warfarin use, the incidence of WICH is expected to rise in the future. When WICH occurs, immediate discontinuation of warfarin with rapid warfarin reversal remains the first-line intervention, often with neurosurgical intervention. The optimal agent for rapid warfarin anticoagulation reversal remains to be defined owing to the lack of prospective randomized trials. We review current literature and prospects for future research for this devastating neurologic emergency.