Global Survey of the Frequency of Atrial Fibrillation–Associated Stroke

Background and Purpose—

Atrial fibrillation (AF) is increasingly recognized as the single most important cause of disabling ischemic stroke in the elderly. We undertook an international survey to characterize the frequency of AF-associated stroke, methods of AF detection, and patient features.

Methods—

Consecutive patients hospitalized for ischemic stroke in 2013 to 2014 were surveyed from 19 stroke research centers in 19 different countries. Data were analyzed by global regions and World Bank income levels.

Results—

Of 2144 patients with ischemic stroke, 590 (28%; 95% confidence interval, 25.6–29.5) had AF-associated stroke, with highest frequencies in North America (35%) and Europe (33%) and lowest in Latin America (17%). Most had a history of AF before stroke (15%) or newly detected AF on electrocardiography (10%); only 2% of patients with ischemic stroke had unsuspected AF detected by poststroke cardiac rhythm monitoring. The mean age and 30-day mortality rate of patients with AF-associated stroke (75 years; SD, 11.5 years; 10%; 95% confidence interval, 7.6–12.6, respectively) were substantially higher than those of patients without AF (64 years; SD, 15.58 years; 4%; 95% confidence interval, 3.3–5.4; P <0.001 for both comparisons). There was a strong positive correlation between the mean age and the frequency of AF ( r =0.76; P =0.0002).

Conclusions—

This cross-sectional global sample of patients with recent ischemic stroke shows a substantial frequency of AF-associated stroke throughout the world in proportion to the mean age of the stroke population. Most AF is identified by history or electrocardiography; the yield of conventional short-duration cardiac rhythm monitoring is relatively low. Patients with AF-associated stroke were typically elderly (>75 years old) and more often women.

Prognostic significance of admission levels of troponin I in patients with acute ischaemic stroke

OBJECTIVES

Successful prediction of cardiac complications early in the course of acute ischaemic stroke could have an impact on the clinical management. Markers of myocardial injury on admission deserve investigation as potential predictors of poor outcome from stroke.

METHODS

We prospectively investigated 330 consecutive patients with acute ischaemic stroke admitted to our emergency department based stroke unit. We analysed the association of baseline levels of cardiac troponin I (cTnI) with (a) all-cause mortality over a six month follow up, and (b) in-hospital death or major non-fatal cardiac event (angina, myocardial infarction, or heart failure).

RESULTS

cTnI levels on admission were normal (lower than 0.10 ng/ml) in 277 patients (83.9%), low positive (0.10-0.39 ng/ml) in 35 (10.6%), and high positive (0.40 ng/ml or higher) in 18 (5.5%). Six month survival decreased significantly across the three groups (p<0.0001, log rank test for trend). On multivariate analysis, cTnI level was an independent predictor of mortality (low positive cTnI, hazard ratio (HR) 2.14; 95% CI 1.13 to 4.05; p = 0.01; and high positive cTnI, HR 2.47; 95% CI 1.22 to 5.02; p = 0.01), together with age and stroke severity. cTnI also predicted a higher risk of the combined endpoint "in-hospital death or non-fatal cardiac event". Neither the adjustment for other potential confounders nor the adjustment for ECG changes and levels of CK-MB and myoglobin on admission altered these results.

CONCLUSIONS

cTnI positivity on admission is an independent prognostic predictor in acute ischaemic stroke. Whether further evaluation and treatment of cTnI positive patients can reduce cardiac morbidity and mortality should be the focus of future research.

Emergency and early carotid endarterectomy in patients with acute ischemic stroke selected with a predefined protocol. A prospective pilot study

AIM

The appropriateness of early carotid endarterectomy (CEA) in patients with acute ischemic stroke is still unsettled. The aim of this study was to verify the safety and feasibility of early CEA in a consecutive series of patients with acute ischemic stroke observed in an emergency Department Stroke Unit.

METHODS

During a 24-month study, out of 756 patients with acute ischemic stroke 33 (4.4%) were scheduled for early CEA. Endarterectomy procedures were distinguished according to the time between the onset of stroke and operation as emergency (within 8 hours), early CEA (1-18 days). Patients with impaired consciousness or an infarct larger than 2.5 cm on computed tomographic (CT) or magnetic resonance (MR) scans or both were excluded from surgery. All patients underwent spiral CT, echo-color-Doppler (ECD) sonography, transcranial Doppler (TCD) sonography and, when necessary, MR angiography within 6 hours of admission. No patient underwent conventional angiography. Most patients were operated on under cervical block (CB) anesthesia; general anesthesia (GA) was used only for those with an unstable neurological deficit. Selective shunting was used on the basis of intra-operative transcranial Doppler in patients under GA and the onset or worsening of neurological deficit under CB anesthesia.

RESULTS

Of the 6 patients operated on within a median 6 hours after the onset of stroke, 1 (16.5%) had a fatal hemorrhagic transformation of the infarct, while the remaining 5 (83.5%) stopped fluctuating or progressing and had a favourable neurological outcome. Of the 16 patients operated on within a median 36 hours and of the 11 patients operated on within 7 days, none deteriorated after operation.

CONCLUSION

Emergency CEA is feasible for acute ischaemic stroke provided that strict selection criteria are applied and the door-to-surgery interval is kept short (within 8 hours). Early CEA for secondary prevention is feasible and safe, confirming that a delayed operation is in most cases unwarranted. Large randomized trials are warranted before implementing emergent and early CEA in routine clinical practice.

Treatment of cerebrovascular diseases: state of the art and perspectives

Ischaemic penumbra is defined as the area of brain tissue that maintains some blood flow following ischaemic accident. This zone may be rescued by both neuroprotection and arterial revascularization. Early thrombolysis has been used with encouraging results since 1995 in several trials testing both streptokinase and recombinant tissue plasminogen activator (r-TPA): the r-TPA results are definitely more positive than those of streptokinase, despite an increased incidence of symptomatic haemorrhagic transformation, r-TPA significantly reducing death or dependency at the end of follow-up. Despite the fact that some experimental periods of application of these therapeutic strategies demonstrated real cost-effective benefits, only 1% of patients reaching hospital in time for thrombolysis are currently treated. This is because the profile of patients at risk of haemorrhagic transformation, which is definitely the most feared side-effect of thrombolysis in stroke, is yet to be clearly defined. Extended computerized tomography (CT) signs of the index stroke have been repeatedly indicated as reliable predictors of haemorrhagic transformation even if currently there are significant discrepancies in the criteria adopted by different researchers to define early CT signs. Based on experimental ischaemia, strategies for protecting the basal lamina during thrombolysis are suggested: neuroprotection is the second approach to stroke therapy; pharmacological reperfusion and brain protection are probably mutually dependent.

Keynote address

"Acute strokes are here to stay": this could be the sad conclusion after decades of stroke research. Generalized prevention of ischemic stroke is not fully successful. After the decline in stroke incidence observed by 1970, partly related to better management of vascular risk factors, there has again been an increase in stroke frequency all around the world. This phenomenon may be explained by the lack of educational modalities for modification of lifestyle behavior, the small impact of high-risk individual prevention strategy, and the lack of rationale and guidelines for multiple approaches. In the meantime, the benefits of acute intensive management of stroke have been demonstrated. There is now considerable evidence that careful monitoring and management of general and cerebral functions in a dedicated stroke unit or by a specialized stroke team are superior to management in a neurologic or general ward. Currently, one way of optimizing limited personnel resources is to connect the stroke unit of a main hospital with peripheral hospitals via a computer network. Experts in the central stroke unit can then make on-line evaluations of CT and ultrasound examinations performed in the local hospital and recommend the best course of patient management. This new approach of treating stroke as an emergency will also require educational programs directed at the general public, general practitioners, and primary and emergency department physicians, to teach the recognition of stroke symptoms and the importance of treating stroke with the same urgency as for myocardial infarction (MI).

Relationship between vascular enhancement, cerebral hemodynamics, and MR angiography in cases of acute stroke

BACKGROUND AND PURPOSE

The use of MR angiography and contrast-enhanced T1-weighted MR imaging in cases of acute cerebral ischemia may be helpful in the evaluation of middle cerebral artery (MCA) occlusion and leptomeningeal collaterals, respectively. The aim of our work was to investigate the relationship between MCA occlusion, T1-weighted vascular contrast enhancement, hemodynamic alterations, and tissue damage in cases of acute ischemic stroke.

METHODS

We studied the MCA territory in 15 patients with acute ischemic stroke within 8 hr of symptom onset. The first MR imaging study (<8 hr after onset) comprised diffusion-weighted imaging, MR angiography, perfusion-weighted imaging, and contrast-enhanced T1-weighted MR imaging sequences. Follow-up MR imaging, performed 1 week later, consisted of MR angiography and T2-weighted fluid-attenuated inversion recovery MR imaging.

RESULTS

Early MR angiography showed MCA stem occlusion in nine of 15 patients. Patients with MCA occlusion had significantly larger areas of abnormality on early diffusion-weighted images, significantly larger areas of altered hemodynamics, larger final lesion volumes, and poorer clinical outcome. Among the nine patients with MCA stem occlusion, vascular enhancement was marked in seven and absent in two who had complete MCA infarcts and poor clinical outcome. Among patients with MCA patency, vascular enhancement was marked in only one, mild in four, and absent in one. Patients with marked vascular enhancement had significantly larger regions of altered hemodynamics and significantly higher asymmetries in both regional cerebral blood volume and mean transit time because of increased values in the affected hemisphere.

CONCLUSION

Among patients with stroke with MCA occlusion, marked vascular enhancement and increased blood volume indicate efficient leptomeningeal collaterals and compensatory hemodynamic mechanisms.

[Nursing documentation in the Stroke Unit]

The organization of Stroke Unit improved prognosis of stroke patient. The randomized studies emphasized the importance of nursing in such a structure. In order to improve nursing process in our Stroke Unit, we designed a nurse record which includes a neurological scale, to define dependence classes and guidelines based on Virgina Henderson's theoretical model. In this paper, we present this nurse record and we describe the various steps of its design.

Identification of lacunar infarcts before thrombolysis in the ECASS I study

BACKGROUND

The identification of lacunar infarcts before thrombolysis would make it possible either to exclude them from treatment or to show that they also may benefit from it.

OBJECTIVE

To determine whether clinical presentation or early CT findings of patients enrolled in the first European Cooperative Acute Stroke Study (ECASS I) trial would identify lacunar infarcts before treatment.

METHODS

Predictive values, sensitivity, specificity, and accuracy of clinical presentation as pure motor hemiparesis (PMH) or sensorimotor stroke (SMS) syndromes and of baseline CT findings in predicting lacunar infarcts were calculated in the ECASS I patients.

RESULTS

Of 514 patients, 44 placebo (17%) and 44 recombinant tissue plasminogen activator (rt-PA) (18%) patients had PMH/SMS involving at least two of three areas. Thirty-one placebo (12%) and 32 rt-PA (13%) patients had PMH/SMS involving three areas. The 7-day CT was compatible with a lacunar infarct in 32 placebo (12%) and 44 rt-PA (18%) patients. PMH/SMS involving at least two areas had a positive predictive value of 30% both in placebo and rt-PA patients, whereas positive predictive values of the involvement of three areas were 23% and 31%. Those of absence of early CT signs were 21% and 30%, and those of leukoaraiosis or previous lacunar infarcts were 21% and 23%. Positive predictive values of PMH/SMS involving at least two areas combined with absence of early CT signs were 36% in placebo and 33% in t-PA patients, and those of PMH/SMS plus leukoaraiosis or previous lacunes were 28% and 7%, respectively.

CONCLUSIONS

In the ECASS I trial, lacunar infarcts were not recognizable on clinical grounds, and early CT findings, alone or in combination with the clinical picture, added poorly to the differential diagnosis.

Computed tomography findings in the first few hours of ischemic stroke: implications for the clinician

In order to evaluate the clinical usefulness of emergency computed tomography (CT) in acute ischemic stroke, we assessed whether CT findings within the first few hours of stroke onset reliably predict type, site and size of the index infarction, and risk of death or disability. For this reason we reviewed clinical and CT findings in a cohort of unselected consecutive patients referred to the stroke unit of a large urban hospital because of a presumed ischemic stroke in the anterior circulation (AC), and submitted to CT within 5 h from onset. Out of 158 total patients, emergency CT revealed parenchymal changes compatible with AC focal ischemia in 77 (49%) and a hyperdense middle cerebral artery (MCA) in 41 (26%). Parenchymal changes and hyperdense MCA predicted an AC territorial infarction respectively in 97% of cases (95% C.I. 93% to 100%) and in 95% of cases (95% C.I. 88% to 100%). Site and size of early changes coincided with those of final lesions in 79% of patients with cortical changes and in 95% of patients with cortico-subcortical changes, but only in 37% of patients with initial subcortical changes, the remainder of whom developed a cortico-subcortical infarction. At logistic regression parenchymal changes were the only independent predictor of an AC territorial infarction. Negative predictive power, however, was only 40% (95% C. I. 29% to 51%) for parenchymal changes, and 35% for hyperdense MCA (95% C.I. 26% to 44%). The odds for death or disability at 1 month associated with parenchymal changes were thrice as high as with negative CT, even after adjustment for clinical severity on admission. These results indicate that CT scan adds significantly to the prediction of outcome made on clinical grounds. The frequent development of a territorial infarction in patients with initially negative CT and the subsequent recruitment of the cortex in those initially exhibiting only subcortical changes suggest that the transition from ischemia to infarction often occurs after the first five h following stroke.

[Treatment of cerebral infarction: is there a reasons for hope?]

Physiopathologic bases of ischemic stroke treatment in acute phase are known since the seventies. Although few molecules have proved their efficacy in experimental models, no effective treatment is already available. Therapeutical trials about cerebral neuroprotectors efficacy and safety are still ongoing. On the other hand, studies concerning fibrinolytics have reached a conclusion the last year. Even if the fibrinolysis remains a dangerous treatment, to be administered with circumspection and in selected patients, if is the first treatment who has demonstrate an efficacy in stroke. Then, we have some reasons to be optimist and have to pursue on this way in order to nearly define a therapeutical scheme associating cerebral neuroprotection and fibrinolysis.

Acute ischemic strokes improving during the first 48 hours of onset: predictability, outcome, and possible mechanisms. A comparison with early deteriorating strokes

BACKGROUND AND PURPOSE

Our aims were to identify predictors of early neurological improvement in acute ischemic stroke patients, to evaluate its impact on clinical outcome, and to investigate possible mechanisms.

METHODS

A consecutive series of 152 first-ever ischemic hemispheric stroke patients hospitalized within 5 hours of onset underwent a first CT scan within 1 hour of hospitalization, and the initial subset of 80 patients also underwent angiography. During the first 48 hours of hospital stay, an increase or a decrease of 1 or more points in the admission Canadian Neurological Scale (CNS) score was defined as early improvement or early deterioration, respectively. Repeated CT scan or autopsy was performed 5 to 9 days after stroke.

RESULTS

Thirty-four patients (22%) improved, 84 (56%) remained stable, and 34 (22%) deteriorated. Logistic regression, which took into account vascular risk factors, baseline clinical and CT data, and therapies administered, selected younger age, lower admission CNS score, and absence of early hypodensity at first CT as independent predictors of early improvement. Among the patients who underwent angiography, logistic regression selected arterial patency and presence of collateral blood supply as independent predictors of early improvement. At the repeated CT scan or autopsy, improving patients presented the highest frequency of small infarcts. Thirty-day case-fatality rate and disability were lower in improving patients. Variables independently associated with outcome at logistic regression were admission CNS score, early deterioration, and early improvement.

CONCLUSIONS

Early improvement can be predicted by the absence of early CT hypodensity and is highly predictive of good outcome. Presence of collateral blood supply and presumably early spontaneous recanalization are likely to be the mechanisms underlying early improvement.

Posterior circulation infarcts simulating anterior circulation stroke. Perspective of the acute phase

BACKGROUND AND PURPOSE

Ischemic stroke patients whose initial clinical presentation suggests an involvement of the anterior circulation (AC) are sometimes found to have a posterior circulation (PC) infarct, a fact that may generate erroneous decisions in clinical management. We investigated the prevalence of this misdiagnosis in the first few hours after stroke onset.

METHODS

We performed a cohort study of 158 patients hospitalized within 5 hours of onset of a presumed AC ischemic stroke, as diagnosed on clinical grounds.

RESULTS

Final CT or pathology diagnosis was AC infarct in 128 patients (81%), a repeatedly negative CT in 14 (9%), PC infarct (5 pons, 1 midbrain and cerebellum, 6 supratentorial territory of the posterior cerebral artery) in 12 (8%), and other or undiagnosed lesions in 4 (3%). AC and PC stroke patients did not differ in terms of age, vascular risk factors, and initial severity, but the latter were more frequently men (83% versus 53%; P = .04), were hospitalized later (mean +/- SD, 168 +/- 86 versus 109 +/- 55 minutes; P = .001), and presented a pure motor hemiparesis or a sensorimotor stroke (50% versus 33%) more often than their counterparts. At baseline CT, PC stroke patients never exhibited an early parenchymal hypodensity in the carotid territory or a hyperdense middle cerebral artery, which were instead found in 59% (P = .0003) and 31% (P = .02) of AC stroke patients, respectively. Early neurological deterioration, 1 month case-fatality rate, and disablement in survivors were comparable in the two groups.

CONCLUSIONS

Shortly after onset the clinical discrimination between AC and nontypical PC infarcts is not reliable, which explains the frequent occurrence of this misdiagnosis. Emergency CT scan helps in the differential diagnosis only when it demonstrates an early focal hypodensity within the carotid territory.