Is Impaired Autoregulation Associated with Mortality in Patients with Severe Cerebral Diseases?

BACKGROUND: Cerebral autoregulation (CA) is a mechanism that compensates for variations in cerebral perfusion pressure (CPP) by changes in cerebral blood flow resistance to keep the cerebral blood flow constant. In this study, the relationship between lethal outcome during hospitalisation and the autoregulation-related indices PRx and Mx was investigated. MATERIALS AND METHODS: Thirty patients (aged 18-77 years, mean 53 ± 16 years) with severe cerebral diseases were studied. Cerebral blood flow velocity (CBFV), arterial blood pressure (ABP) and intracranial pressure (ICP) were repeatedly recorded. CA indices were calculated as the averaged correlation between CBFV and CPP (Mx) and between ABP and ICP (PRx). Positive index values indicated impairment of CA. RESULTS: Six patients died in hospital. In this group both PRx and Mx were significantly higher than in the group of survivors (PRx: 0.41 ± 0.33 vs 0.09 ± 0.25; Mx: 0.28 ± 0.40 vs 0.03 ± 0.21; p = 0.01 and 0.04, respectively). PRx and Mx correlated significantly with Glasgow Outcome Scale (GOS) score (PRx: R = -0.40, p < 0.05; Mx: R = -0.54, p < 0.005). PRx was the only significant risk factor for mortality (p < 0.05, logistic regression). CONCLUSION: Increased PRx and Mx were associated with risk of death in patients with severe cerebral diseases. The relationship with mortality was more pronounced in PRx, whereas Mx showed a better correlation with GOS score.

Noninvasive Assessment of ICP: Evaluation of New TBI Data.

BACKGROUND: In a previously introduced mathematical model, intracranial pressure (ICP) was noninvasively assessed using cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP). In this study this method is evaluated using new data from patients with traumatic brain injury (TBI). MATERIALS AND METHODS: Three hundred fifteen data recordings of 137 patients (114 men; age 14-78 years, mean age 37 ± 17 years) with severe TBI were studied. CBFV, ABP, and invasively assessed ICP were simultaneously recorded for 1 h. Noninvasive ICP (nICP) was calculated and compared with ICP. RESULTS: On 315 recordings, average deviation between ICP and nICP (± standard deviation) was 4.9 ± 3.3 mmHg. The standard deviation of differences (ICP - nICP) was 5.6 mmHg. The 95 % confidence interval of ICP prediction ranged from -9.6 to 12.3 mmHg. Mean ICP was 16.7 mmHg and mean nICP was 18.0 mmHg. When nICP was adjusted by their difference 1.3 mmHg (nICPadj = nICP - 1.3), the 95 % confidence limits of ICP prediction became ±11.0 mmHg. In recordings with highly dynamic ICP signals (n = 27), ICP and nICP correlated on average with R = 0.51 ± 0.47. CONCLUSIONS: nICP assessment showed reasonable accuracy and may be used in clinical studies of patients without any indication for ICP probe implantation.

Thrombus age does not differentiate between cardiogenic and atherosclerotic strokes.

Objective: Interventional stroke therapy made thrombi available for histological analysis. Unfortunately, simple composition aspects such as erythrocyte versus fibrin/platelet rich did not allow a feasible allocation to thrombi's cardiac or carotid origin. Since the mentioned criteria represent characteristics of thrombus age, we used established histological criteria for determining thrombus age in patients who had an atherosclerotic (TOAST (Trial of Org 10172 in Acute stroke Treatment) 1) stroke versus patients who had a cardioembolic (TOAST 2) stroke. Methods: We assessed prospectively data from stroke patients presenting with occlusion of the middle cerebral artery eligible for catheter-based intervention. Besides patient characteristics and stroke workup, extracted thrombi were classified into different age categories according to their cellular to fibrotic transition. Thrombi were collected in an erythrocyte lysing solution to reduce acute clotting effects. Statistics were done with a non-parametric Kolmogorov-Smirnov test. Results: 170 patients were included, of which 50 (38 men; 73±12 years) had a TOAST 1 and 99 (59 women; 75±10 years) had a TOAST 2 categorised stroke. Age, National Institutes of Health Stroke Score (13±7 vs 15±7), Alberta Stroke Program Early CT Score (9±3 vs 9±2), Thrombolysis in Cerebral Infarction Score (2.9±0.2 vs 2.9±0.3), modified Rankin Score on discharge (3.2±2 vs 3.2±2), number of vascular risk factors (0.9±1.4 vs 1.0±1.1) or time span between symptom onset to reperfusion (266±115 vs 260±128 min) remained non-significant. Also, thrombus age did not differ between the groups. The mean age of thrombi was 5-8 days. However, the male-female ratio differed significantly (p<0.0005) between groups, with more men in TOAST 1 group and more women in TOAST 2 group. Conclusion: Age aspects of thrombi seem not feasible to allow reliable source allocation. However, the young age of thrombi points to a rapid detachment. The difference in sex relation is in line with previous reports.

Case management-based post-stroke care for patients with acute stroke and TIA (SOS-Care): a prospective cohort study.

BACKGROUND: The high incidence of stroke recurrence necessitates effective post-stroke care. This study investigates the effectiveness of a case management-based post-stroke care program in patients with acute stroke and TIA. METHODS: In this prospective cohort study, patients with TIA, ischemic stroke or intracerebral hemorrhage were enrolled into a 12-month case management-based program (SOS-Care) along with conventional care. Control patients received only conventional care. The program included home and phone consultations by case managers, focusing on education, medical and social needs and guideline-based secondary prevention. The primary outcome was the composite of stroke recurrence and vascular death after 12 months. Secondary outcomes included vascular risk factor control at 12 months. RESULTS: From 11/2011 to 12/2020, 1109 patients (17.9% TIA, 77.5% ischemic stroke, 4.6% intracerebral hemorrhage) were enrolled. After 85 (7.7%) dropouts, 925 SOS-Care patients remained for comparative analysis with 99 controls. Baseline characteristics were similar, except for fewer males and less frequent history of dyslipidemia in post-stroke care. At 12 months, post-stroke care was associated with a reduction in the composite endpoint compared to controls (4.9 vs. 14.1%; HR 0.30, 95% CI 0.16-0.56, p < 0.001), with consistent results in ischemic stroke patients alone (HR 0.32, 95% CI 0.17-0.61, p < 0.001). Post-stroke care more frequently achieved treatment goals for hypertension, dyslipidemia, diabetes, BMI and adherence to secondary prevention medication (p < 0.05). CONCLUSIONS: Case management-based post-stroke care may effectively mitigate the risk of vascular events in unselected stroke patients. These findings could guide future randomized trials investigating the efficacy of case management-based models in post-stroke care.

Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age.

INTRODUCTION: A number of studies has addressed the possible association between patent foramen ovale (PFO) and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke. METHODS: To address the role of PFO for the occurrence of cerebral ischemia, we investigated the prevalence of right-to-left shunt in a large group of patients with acute stroke or TIA. 763 consecutive patients admitted to our hospital with cerebral ischemia were analyzed. All patients were screened for the presence of PFO by contrast-enhanced transcranial Doppler sonography at rest and during Valsalva maneuver. Subgroup analyses were performed in patients stratified for gender, age and origin of stroke. RESULTS: A right-to-left shunt was detected in 140 (28%) male and in 114 (42%) female patients during Valsalva maneuver, and in 66 (13%) and 44 (16%) at rest respectively. Patients with right-to-left shunt were younger than those without (P < 0.001). PFO was associated with stroke of unknown origin in male (P = 0.001) but not female patients (P > 0.05). After adjusting for age no significant association between PFO and stroke of unknown origin was found in either group. CONCLUSION: Our findings argue against paradoxical embolization as a major cause of cerebral ischemia in patients with right-to-left shunt. Our data demonstrate substantial gender-and age-related differences that should be taken into account in future studies.

Adaptive noninvasive assessment of intracranial pressure and cerebral autoregulation.

BACKGROUND AND PURPOSE: A mathematical model has previously been introduced to estimate noninvasively intracranial pressure (nICP). In the present multicenter study, we investigated the ability of model to adapt to the state of cerebral autoregulation (SCA). This modification was intended to improve the quality of nICP estimation and noninvasive assessment of pressure reactivity of the cerebrovascular system. METHODS: We studied 145 patients after severe head injuries or stroke. All patients had direct ICP, arterial blood pressure (ABP), and transcranial Doppler middle cerebral artery blood flow velocity (FV) monitored. The SCA was assessed by moving correlation (Mx index) of cerebral perfusion pressure (CPP=ABP-ICP) and cerebral blood flow velocity and correlation of ABP and ICP (PRx index). nICP was calculated from ABP and FV waveforms. When nICP was used instead of ICP, the SCA was continuously estimated, and the model was dynamically adapted to the SCA. RESULTS: High and moderate correlations between invasively (Mx, PRx) and noninvasively (nMx, nPRx) estimated autoregulation indexes were observed (Mx: R=0.90, P<0.001; PRx: R=0.62, P<0.001). Values of Mx and nMx indicated contradictory SCA in 4 of 167 evaluated recordings; values of PRx and nPRx were contradictory in 27 recordings. When the model was adapted to the SCA, the mean error of ICP estimation decreased significantly (P<0.005). CONCLUSIONS: Continuous adaptation of the model to SCA improves the accuracy of noninvasive estimation of ICP and ICP dynamics. The same model provides a noninvasive and continuous assessment of SCA.