Hematologic abnormalities occur in both cortical and lacunar infarction

The Potential Impact of Neuroimaging and Translational Research on the Clinical Management of Lacunar Stroke

Lacunar infarcts represent one of the most frequent subtypes of ischemic strokes and may represent the first recognizable manifestation of a progressive disease of the small perforating arteries, capillaries, and venules of the brain, defined as cerebral small vessel disease. The pathophysiological mechanisms leading to a perforating artery occlusion are multiple and still not completely defined, due to spatial resolution issues in neuroimaging, sparsity of pathological studies, and lack of valid experimental models. Recent advances in the endovascular treatment of large vessel occlusion may have diverted attention from the management of patients with small vessel occlusions, often excluded from clinical trials of acute therapy and secondary prevention. However, patients with a lacunar stroke benefit from early diagnosis, reperfusion therapy, and secondary prevention measures. In addition, there are new developments in the knowledge of this entity that suggest potential benefits of thrombolysis in an extended time window in selected patients, as well as novel therapeutic approaches targeting different pathophysiological mechanisms involved in small vessel disease. This review offers a comprehensive update in lacunar stroke pathophysiology and clinical perspective for managing lacunar strokes, in light of the latest insights from imaging and translational studies.

Biochemical markers in vascular cognitive impairment associated with subcortical small vessel disease - A consensus report

Background

Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data.

Method

The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized.

Results

This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer’s disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood–brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau.

Conclusions

Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.

Von Willebrand factor, P-selectin and fibrinogen levels in patients with acute ischaemic and haemorrhagic stroke, and their relationship with stroke sub-type and functional outcome

Although ischaemic stroke is associated with accentuated platelet function, it remains unclear whether this applies to all sub-types, especially lacunar infarcts, which differ from cortical infarction in their patho-aetiology. Similarly, conflicting evidence suggests that haemorrhagic stroke may, or may not, be associated with a hypothrombotic state. Levels of von Willebrand factor (vWF), fibrinogen, and P-selectin were measured within 48 h of ictus in 163 patients with acute ischaemic stroke and 40 patients with acute primary intracerebral haemorrhage, and 33 age, gender and race matched-controls. vW F (IU/dl) was significantly increased in both cortical and lacunar ischaemic stroke, and haemorrhagic stroke, as compared with controls, median (semiquartile range): 158 (25) vs 144 (19) vs 147 (24) vs 114 (16), respectively. Similarly, fibrinogen (g/litre) was increased: 4.80 (0.90) vs 4.65 (0.70) vs 4.35 (0.83) vs 3.70 (0.70). In contrast, soluble P-selectin (ng/ml) was increased in cortical stroke as compared with lacunar infraction patients or controls: 408 (101) vs 300 (108) vs 324 (121), respectively; P-selectin was not increased in haemorrhagic stroke, 360 (153). Both vW F and fibrinogen correlated with 3-month functional outcome (modified Rankin score): r = 0.371 (2 P = 0.0006), and r = 0.195 (2 P = 0.042), respectively; however, P-selectin was not associated with outcome: r = 0.188 (2 P = 0.084). The results suggest that increases in vW F and fibrinogen in all types of stroke reflect an acute phase response; in contrast, increased soluble P-selectin levels in cortical stroke, but not lacunar infarction, suggest that platelets contribute to the patho-aetiology of some subtypes of ischaemic stroke.

Cerebral small vessel disease: genetic risk assessment for prevention and treatment

Cerebrovascular disease is a major burden to individuals and their communities worldwide. Stroke is one of the leading causes of death and disability, and the prevention and treatment of stroke can be improved with a better understanding of its causation. Cerebral small vessel disease (SVD) is a subset of cerebrovascular disease, and has an equally large impact on an individual's quality of life. Although many risk factors are involved, we propose that genetics has a significant role in the pathogenesis of SVD through a complex interplay of environmental and multigenetic factors. Advances in molecular technology have enabled the human genome to be investigated both at a population and, more recently, an individual level. A better understanding of the molecular basis of SVD will enable the development of therapies to help in its prevention and treatment. This review assesses the molecular genetics underlying cerebral SVD.

Classic risk factors, hypercoagulability and migraine in young women with cerebral lacunar infarctions

OBJECTIVE

Lacunar cerebral infarctions (LACI) in young women is a rare condition which pathogenesis is still not fully recognized. We explored the presence of classic risk factors, hypercoagulability and migraine in young women with LACI.

METHODS

Charts of 192 consecutive premenopausal women suffering cerebrovascular insult [125 (65%) haemorhagic, 58 (30%) ischaemic and 9 (5%) unclassified] during a period of 5 years were reviewed. Sixteen out of 58 (27%) patients with ischaemic stroke were identified to have LACI and included in a study.

RESULTS

Ten and seven out of 16 LACI women had at least one classical risk factor (hypertension, hyperlipidaemia, smoking or oral contraceptives) or migraine, respectively. LACI patients had slight hypercoagulable state indicated by shorter thrombin and thromboplastin times, higher fibrinogen and higher t-PA antigen than 47 age matched controls (all P < 0.05). In addition in LACI patients with migraine the trend toward more pronounced hypercoagulable state in comparison to LACI patients without migraine was found. The combination of migraine, at least one classic risk factor and hypercoagulability was present in 5/16 (31.25%) of patients.

CONCLUSIONS

The combination of slightly to moderately expressed classic risk factors, hypercoagulability and migraine might be a risk profile for LACI in young women. Further studies are needed to clarify risk profile, rather than isolated risk factors, for LACI in a specific group as young women are.

Abnormal haemorheology, endothelial function and thrombogenesis in relation to hypertension in acute (ictus < 12 h) stroke patients: the West Birmingham Stroke Project

While the blood vessels are exposed to high pressures in hypertension, the main complications of hypertension (stroke and myocardial infarction) are paradoxically thrombotic rather than haemorrhagic. To investigate abnormalities of haemorheology (plasma viscosity, fibrinogen), endothelial dysfunction (von Willebrand factor), platelet activation (soluble P-selectin) and thrombogenesis (plasminogen activator inhibitor and fibrin D-dimer) in stroke and the effects of concurrent hypertension, we studied 86 consecutive patients (58 male, 28 female) aged < 75 years (mean age +/- SD, 64.2 +/- 9.2 years) with acute stroke (ictus < 12 h). Baseline blood tests on admission were compared with 46 'hospital controls' (patients with uncomplicated essential hypertension; mean age +/- SD, 65.9 +/- 3.8 years) and 24 healthy normotensive controls (mean age +/- SD, 65 +/- 14.0 years). Further comparisons were made between stroke patients with hypertension (systolic blood pressure > 160 mmHg and/or diastolic > 90 mmHg) on admission and those without hypertension. Mean plasma viscosity (one-way analysis of variance, P = 0.026) and fibrinogen levels (P = 0.016) were significantly higher in stroke patients and hospital controls, when compared with healthy controls. The von Willebrand factor, plasminogen activator inhibitor soluble P-selectin and fibrin D-dimer levels were highest in the acute stroke patients, intermediate in hospital controls and lowest in healthy controls (all P < or = 0.001). There were no significant differences in measured indices of haemorheology, endothelial dysfunction and thrombogenesis between the three stroke pathological subtypes (ischaemic/thrombotic, haemorrhagic or transient ischaemic attack). There were also no significant differences in the measured parameters for stroke patients with or without systolic blood pressure > 160 mmHg or diastolic blood pressures > 90 mmHg using clinical (manual) readings or mean daytime or night-time ambulatory blood pressure monitoring recordings. There were no statistically significant differences between the measured parameters on admission and at 3 months follow-up in 26 patients (all P = not significant). Plasma viscosity was significantly correlated with mean daytime systolic blood pressure (r = 0.314, P = 0.021) and mean night-time systolic blood pressure (r = 0.309, P = 0.025). This study of hypertension and haemostasis in acute stroke has demonstrated clear abnormalities of haemorheology, endothelial dysfunction, platelet activation and thrombogenesis, which do not appear to be affected by the height of the blood pressure or the presence of hypertension. This is despite the known hypercoagulable state found in hypertension and the relationship of haemostatic abnormalities to vascular complications.

Activation of thrombosis and fibrinolysis following brain infarction

To clarify the sequence of alterations in the thrombotic and fibrinolytic systems after acute brain infarction, we prospectively examined sequential changes in coagulatory markers in 38 patients suffering from cardioembolic infarcts (CEI), 41 patients with atherothrombotic infarcts (ATI), 58 patients with lacunar infarcts (LI), and 32 age-matched controls. The plasma level of thrombin-antithrombin III complex (TAT), fibrinopeptide A (FpA), D-dimer, fibrin degradation products-E (FDP-E), fibrinogen, alpha2-plasmin inhibitor-plasmin complex (PIC), and percent activity of antithrombin III (AT-III) were measured within 48 h, at 1 week, and at 3 weeks after the stroke onset. Significantly elevated levels of TAT and FpA, which are both markers of thrombin formation, were observed in CEI patients, and these elevated levels were associated with increasing D-dimer levels for 3 weeks (P<0.0001). D-Dimer in CEI patients was significantly elevated compared to control, LI and ATI levels within 48 h (P<0.001). Percent activity of AT-III was significantly decreased in CEI patients for 3 weeks compared to this activity in controls, LI and ATI (P<0.001). TAT and FpA also increased significantly within 48 h in ATI subjects and declined thereafter. A significant elevation of FDP-E (P<0.001) and D-dimer (P<0.05, P<0.01) was detected in parallel with increasing fibrinogen for 3 weeks. However, there was no significant depletion of percent activity of AT-III in ATI. In LI subjects, no significant elevation of TAT, D-dimer or FDP-E were observed within 1 week. PIC increased significantly in three subtypes of brain infarcts, but did not differ significantly among the three subtypes for 3 weeks. An accurate assessment of sequential alterations in thrombotic and fibrinolytic markers in the acute stage of brain infarct should contribute to the clinical diagnosis of brain infarct subtype. Alterations in these markers in response to activation of the coagulatory system are attributable to the different pathogenesis of ischemic stroke.

Effectiveness of heparin treatment for progressing ischaemic stroke: before and after study

OBJECTIVES

During the acute phase of stroke, symptoms progress in 25% of patients, resulting in a worse outcome. Could heparin treatment improve the situation?

DESIGN

Before and after study. During the first period, no treatment was given to patients with progress of symptoms, whereas heparin was used regularly in the second period. A comparison of outcome was performed.

SETTING

Patients with acute stroke cared for in stroke units of two big emergency hospitals in Stockholm. Besides heparin treatment, the groups were taken care of according to the same basic principles.

SUBJECTS

Consecutive patients admitted to a stroke unit during two periods of time. The first study comprised 314 patients with ischaemic stroke and the second 907.

INTERVENTION

In the treatment period, patients with ischaemic stroke and objectively recognized progression received heparin infusion for at least 5 days.

MAIN OUTCOME MEASURES

Continued progression, length of stay, unaided walking at discharge, discharge destination and mortality.

RESULTS

The progression rate was non-significantly higher in the first period: 28 vs. 21%. One-third continued to progress regardless of treatment given. Patients with progression, treated and untreated alike, had 40% longer stay in the stroke unit compared with stable patients, whereas mortality was unaffected. Treatment did not reduce the proportion of patients who needed aid for walking at discharge (77 vs. 74%) or those who needed further institutionalized care (65 vs. 66%).

CONCLUSION

Progression of focal stroke symptoms still constitutes a serious clinical problem for which heparin has insufficient effectiveness in clinical practice. New therapies, ideally preventive, are needed.

Antithrombin-III Activity and the Efficacy of Heparin in Progressing Ischemic Stroke

Heparin is often used in progressing ischemic stroke. However, a substantial part of the patients continue to progress while on treatment. The purpose of this study was to evaluate if antithrombin (AT) III activity before treatment could predict patients at risk for continued progression or if heparin-induced reduction in AT-III activity during treatment is related to continued progression. The study included 42 acute stroke patients with heaprin treatment for progression of isch emic stroke. The patients were continuously supervised for progression. Intravenous heparin therapy was started as soon as possible after the progression was noticed. Antithrombin-III activity was assessed before initiation of treatment and daily during the treatment period. Nine (21 %) of the 42 patients continued to progress while on treatment. There was no statis tically significant difference in AT III activity before treatment between patients who continued to progress and those where the progression ceased when treatment was initiated. Nor were there any differences in the mean AT III activity levels during treatment for patients with more or less favorable clinical course. The individual changes (Δ AT III) were similar in both patient groups as was the proportion of patients with their low est AT III activity in the thrombogenic range (continued: 22% vs. ceased: 27%). No clinically relevant influence of AT III activity on heparin efficacy in progressing ischemic stroke was found. Key Words: Stroke progression—Heparin treatment— Antithrombin activity.

[Cerebral infarctions in young patients related to deficiency of natural anticoagulants. Protein C and protein S]

The possible etiologies of cerebral infarcts (CI) in young patients differ from those in the older stroke population. Recently, deficiencies of fibrinolytic factors emerged as an important etiology of stroke in the young population. The literature has emphasized the diagnosis of such conditions especially in stroke cases of undetermined etiology and with history of recurrent thrombosis. We carried out a research on the serum level of protein C, protein S, and antithrombin III in young patients, between 15 and 40 years, with CI of undetermined cause after application of a standard protocol. Three patients had low levels of these proteins; two had protein C deficiency, and one protein S deficiency. None of them had antithrombin III deficiency. We conclude that systematic investigation of such causes of cerebral infarct will reduce the group of undetermined strokes, and will open the possibility of prophylactic treatment in a non-negligible group of patients.

[The importance of clinical hemorheology in the study of cerebral blood flow in normal conditions and in cerebrovascular ischemia]

A critical review on the importance of hemorheology for establishing clinical management of acute cerebrovascular insufficiency is presented. With this purpose a revision is made on cerebral blood flow, acute cerebrovascular insufficiency, and clinical hemorheology. Data support an evaluation on main drugs presently used in the management of stroke, and on general principles adopted for medical treatment and prevention of stroke.