Recent evidence indicates that our understanding of the relationship between cardiac function and ischemic stroke remains incomplete. The Cardiovascular Health Study enrolled community-dwelling ...adults ≥ 65 years old. We included participants with speckle-tracking data from digitized baseline study echocardiograms. Exposures were left atrial reservoir strain (primary), left ventricular longitudinal strain, left ventricular early diastolic strain rate, septal e' velocity, and lateral e' velocity. The primary outcome was incident ischemic stroke. Cox proportional hazards models were adjusted for demographics, image quality, and risk factors including left ventricular ejection fraction and incident atrial fibrillation. Among 4,000 participants in our analysis, lower (worse) left atrial reservoir strain was associated with incident ischemic stroke (HR per SD absolute decrease, 1.14; 95% CI 1.04-25). All secondary exposure variables were significantly associated with the outcome. Left atrial reservoir strain was associated with cardioembolic stroke (HR per SD absolute decrease, 1.42; 95% CI 1.21-1.67) and cardioembolic stroke related to incident atrial fibrillation (HR per SD absolute decrease, 1.60; 1.32-1.95). Myocardial dysfunction that can ultimately lead to stroke may be identifiable at an early stage. This highlights opportunities to identify cerebrovascular risk earlier and improve stroke prevention via therapies for early myocardial dysfunction.
BACKGROUND AND PURPOSE—The risk of arterial ischemic events after intracerebral hemorrhage (ICH) is poorly understood given the lack of a control group in prior studies. This study aimed to evaluate ...the risk of acute ischemic stroke and myocardial infarction (MI) among patients with and without ICH.
METHODS—We performed a retrospective cohort study using claims data from Medicare beneficiaries from 2008 to 2014. Our exposure was acute ICH, identified using validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. Our primary outcome was a composite of acute ischemic stroke and MI, whereas secondary outcomes were ischemic stroke alone and MI alone. We used Cox regression analysis to compute hazard ratios during 1-month intervals after ICH. Sensitivity analyses entailed exclusion of patients with atrial fibrillation and valvular heart disease.
RESULTS—Among 1 760 439 Medicare beneficiaries, 5924 had ICH. The 1-year cumulative incidence of an arterial ischemic event was 5.7% (95% CI, 4.8–6.8) in patients with ICH and 1.8% (95% CI, 1.7–1.9) in patients without ICH. After adjusting for potential confounders, the risk of an arterial ischemic event remained significantly increased for the first 6 months after ICH and was especially high in the first month (hazard ratio, 6.7 95% CI, 5.0–8.6). In secondary analysis, the risk of ischemic stroke was increased in the first 6 months after ICH (hazard ratio, 6.1 95% CI, 3.5–9.3) but the risk of MI was not (hazard ratio, 1.6 95% CI, 0.3–2.9). In sensitivity analyses excluding patients with atrial fibrillation and valvular heart disease, the association between ICH and arterial ischemic events was similar to that of the primary analysis.
CONCLUSIONS—In a large population-based cohort, we found that elderly patients with ICH had a substantially increased risk of ischemic stroke in the first 6 months after diagnosis. Further exploration of this risk is needed to determine optimal secondary prevention strategies for these patients.
In 1978, a landmark study established atrial fibrillation as a risk factor for stroke,1 and over the following 2 decades, a series of randomised trials found that anticoagulation substantially ...reduced the risk of stroke from atrial fibrillation.2 In these studies, atrial fibrillation was established via a standard 12-lead electrocardiogram, meaning that patients classified as having atrial fibrillation had a high enough burden of arrhythmia for it to be captured on a few seconds of heart rhythm monitoring. Subsequently, technological advances in implantable pacemakers, defibrillators, and loop recorders resulted in increased availability of prolonged heart rhythm data and frequent identification of brief atrial fibrillation episodes. HK is a principal investigator for the ARCADIA trial (NIH/NINDS U01NS095869), which received in-kind study drug from the BMS-Pfizer Alliance for Eliquis and ancillary study support from Roche Diagnostics; other funding from NIH (R01HL144541, R01NS123576, U01NS106513); is Deputy Editor for JAMA Neurology; is on clinical trial steering and executive committees for Medtronic and Janssen; is on endpoint adjudication committees for AstraZeneca, Novo Nordisk, and Boehringer Ingelheim; and has household ownership interests in TETMedical, Spectrum Plastics Group, and Burke Porter Group.
Objective
Oral anticoagulation treatment (OAT) resumption is a therapeutic dilemma in intracerebral hemorrhage (ICH) care, particularly for lobar hemorrhages related to amyloid angiopathy. We sought ...to determine whether OAT resumption after ICH is associated with long‐term outcome, accounting for ICH location (ie, lobar vs nonlobar).
Methods
We meta‐analyzed individual patient data from: (1) the multicenter RETRACE study (n = 542), (2) a U.S.‐based single‐center ICH study (n = 261), and (3) the Ethnic/Racial Variations of Intracerebral Hemorrhage study (n = 209). We determined whether, within 1 year from ICH, OAT resumption was associated with: (1) mortality, (2) favorable functional outcome (modified Rankin Scale = 0–3), and (3) stroke incidence. We separately analyzed nonlobar and lobar ICH cases using propensity score matching and Cox regression models.
Results
We included 1,012 OAT‐related ICH survivors (633 nonlobar and 379 lobar). Among nonlobar ICH survivors, 178/633 (28%) resumed OAT, whereas 86/379 (23%) lobar ICH survivors did. In multivariate analyses, OAT resumption after nonlobar ICH was associated with decreased mortality (hazard ratio HR = 0.25, 95% confidence interval CI = 0.14–0.44, p < 0.0001) and improved functional outcome (HR = 4.22, 95% CI = 2.57–6.94, p < 0.0001). OAT resumption after lobar ICH was also associated with decreased mortality (HR = 0.29, 95% CI = 0.17–0.45, p < 0.0001) and favorable functional outcome (HR = 4.08, 95% CI = 2.48–6.72, p < 0.0001). Furthermore, OAT resumption was associated with decreased all‐cause stroke incidence in both lobar and nonlobar ICH (both p < 0.01).
Interpretation
These results suggest novel evidence of an association between OAT resumption and outcome following ICH, regardless of hematoma location. These findings support conducting randomized trials to explore risks and benefits of OAT resumption after ICH. Ann Neurol 2017;82:755–765
BACKGROUND AND PURPOSE—Carotid artery plaque with <50% luminal stenosis may be an underappreciated stroke mechanism. We assessed how many stroke causes might be reclassified after accounting for ...nonstenosing plaques with high-risk features.
METHODS—We included patients enrolled in the Cornell Acute Stroke Academic Registry from 2011 to 2015 who had anterior circulation infarction, magnetic resonance imaging of the brain, and magnetic resonance angiography of the neck. High-risk plaque was identified by intraplaque hemorrhage ascertained from routine neck magnetic resonance angiography studies using validated methods. Infarct location was determined from diffusion-weighted imaging. Intraplaque hemorrhage and infarct location were assessed separately in a blinded fashion by a neuroradiologist. We used the McNemar test for matched data to compare the prevalence of intraplaque hemorrhage ipsilateral versus contralateral to brain infarction. We reclassified stroke subtypes by including large-artery atherosclerosis as a cause if there was intraplaque hemorrhage ipsilateral to brain infarction, regardless of the degree of stenosis.
RESULTS—Among the 1721 acute ischemic stroke patients registered in the Cornell Acute Stroke Academic Registry from 2011 to 2015, 579 were eligible for this analysis. High-risk plaque was more common ipsilateral versus contralateral to brain infarction in large-artery atherosclerotic (risk ratio RR, 3.7 95% CI, 2.2–6.1), cryptogenic (RR, 2.1 95% CI, 1.4–3.1), and cardioembolic strokes (RR, 1.7 95% CI, 1.1–2.4). There were nonsignificant ipsilateral-contralateral differences in high-risk plaque among lacunar strokes (RR, 1.2 95% CI, 0.4–3.5) and strokes of other determined cause (RR, 1.5 95% CI, 0.7–3.3). After accounting for ipsilateral high-risk plaque, 88 (15.2%) patients were reclassified38 (22.6%) cardioembolic to multiple potential etiologies, 6 (8.5%) lacunar to multiple, 3 (15.8%) other determined cause to multiple, and 41 (20.8%) cryptogenic to large-artery atherosclerosis.
CONCLUSIONS—High-risk carotid plaque was more prevalent ipsilateral to brain infarction across several ischemic stroke subtypes. Accounting for such plaques may reclassify the etiologies of up to 15% of cases in our sample.
Natural draft dry cooling towers (NDDCTs) are a type of cooling technology used in thermal power plants, including geothermal power plants. Interest from industry in this technology is increasing due ...to its water saving potential. However, the cooling performance of NDDCTs is inherently negatively impacted by high ambient temperatures. Among all existing solutions to this issue, inlet airflow precooling using water sprays is thought to be a good method to reduce the impact of high ambient temperature on the performance of NDDCTs. In previous studies, spraying of saline water obtained from water sources such as coal seam gas wells (as a by-product) was shown not only to save valuable freshwater resources but also to provide the further possibility of increasing the evaporation rate of water droplets, thereby shortening the wet length (distance) required for the spraying system. However, this benefit has not been verified. To address this knowledge gap, three different water sources were experimentally examined in the current study, viz. fresh, artificial simulated saline water, and real coal seam gas well water. Spraying using these three types of water was compared based on tests in a wind tunnel using a specific type of nozzle. The results confirmed an increase in the cooling efficiency of the spraying system when saline water was selected as the water source. However, the cooling efficiency may be more influenced by the nozzle orientation with respect to the airflow. On the other hand, spraying of saline water resulted in considerable deposition of solid particles from the water droplets in the airflow at 4.5 m downstream of the nozzle after only 2 h of spraying, although no significant nozzle clogging was observed even after the total of 50 h of testing. This effect could potentially cause fouling and corrosion on heat exchanger surfaces.
BACKGROUND AND PURPOSE—Emerging data suggest that left atrial disease may cause ischemic stroke in the absence of atrial fibrillation or flutter (AF). If true, this condition may provide a cause for ...many strokes currently classified as cryptogenic.
METHODS—Among 6741 participants in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cerebrovascular or cardiovascular disease (including AF) at baseline, we examined the association between markers of left atrial abnormality on a standard 12-lead ECG—specifically P-wave area, duration, and terminal force in lead V1—and the subsequent risk of ischemic stroke while accounting for incident AF.
RESULTS—During a median follow-up of 8.5 years, 121 participants (1.8%) had a stroke and 541 participants (8.0%) were diagnosed with AF. In Cox proportional hazards models adjusting for potential baseline confounders, P-wave terminal force in lead V1 was more strongly associated with incident stroke (hazard ratio per 1 SD increase, 1.21; 95% confidence interval, 1.02–1.44) than with incident AF (hazard ratio per 1 SD, 1.11; 95% confidence interval, 1.03–1.21). The association between P-wave terminal force in lead V1 and stroke was robust in numerous sensitivity analyses accounting for AF, including analyses that excluded those with any incident AF or modeled any incident AF as having been present from baseline.
CONCLUSIONS—We found an association between baseline P-wave morphology and incident stroke even after accounting for AF. This association may reflect an atrial cardiopathy that leads to stroke in the absence of AF.
BACKGROUND AND PURPOSE—Emerging evidence suggests that an underlying atrial cardiopathy may result in thromboembolism before atrial fibrillation (AF) develops. We examined the association between ...various markers of atrial cardiopathy and the risk of ischemic stroke.
METHODS—The CHS (Cardiovascular Health Study) prospectively enrolled community-dwelling adults ≥65 years of age. For this study, we excluded participants diagnosed with stroke or AF before baseline. Exposures were several markers of atrial cardiopathybaseline P-wave terminal force in ECG lead V1, left atrial dimension on echocardiogram, and N terminal pro B type natriuretic peptide (NT-proBNP), as well as incident AF. Incident AF was ascertained from 12-lead electrocardiograms at annual study visits for the first decade after study enrollment and from inpatient and outpatient Medicare data throughout follow-up. The primary outcome was incident ischemic stroke. We used Cox proportional hazards models that included all 4 atrial cardiopathy markers along with adjustment for demographic characteristics and established vascular risk factors.
RESULTS—Among 3723 participants who were free of stroke and AF at baseline and who had data on all atrial cardiopathy markers, 585 participants (15.7%) experienced an incident ischemic stroke during a median 12.9 years of follow-up. When all atrial cardiopathy markers were combined in 1 Cox model, we found significant associations with stroke for P-wave terminal force in ECG lead V1 (hazard ratio per 1000 μV*ms 1.04; 95% confidence interval, 1.001–1.08), log-transformed NT-proBNP (hazard ratio per doubling of NT-proBNP, 1.09; 95% confidence interval, 1.03–1.16), and incident AF (hazard ratio, 2.04; 95% confidence interval, 1.67–2.48) but not left atrial dimension (hazard ratio per cm, 0.96; 95% confidence interval, 0.84–1.10).
CONCLUSIONS—In addition to clinically apparent AF, other evidence of abnormal atrial substrate is associated with subsequent ischemic stroke. This finding is consistent with the hypothesis that thromboembolism from the left atrium may occur in the setting of several different manifestations of atrial disease.
Atrial fibrillation (AF) is associated with an increased risk of stroke and death. Uniform utilization of appropriate therapies for AF may help reduce those risks.
We sought to determine whether ...significant race and sex differences exist in the treatment of newly diagnosed AF in Medicare beneficiaries.
We used administrative encounter data for Medicare beneficiaries to identify patients with newly diagnosed AF during 2010-2011. Services received after initial AF diagnosis were cataloged, including visits with a cardiologist or electrophysiologist, catheter ablation procedures, and use of oral anticoagulants, rate control agents, and antiarrhythmic drugs.
Overall, 517,941 patients met study criteria, of whom 452,986 (87%) were white, 36,425 (7%) black, and 28,530 (6%) Hispanic. Male patients comprised 209,788 (41%) of the cohort. In multivariate analysis, there were statistically significant differences in the use of AF-related services by both race and sex, with white patients and male patients receiving the most care. The most notable disparities were for catheter ablation (Hispanic vs white: adjusted hazard ratio AHR 0.70; 95% confidence interval CI 0.63-0.79; P < .001; female vs male: AHR 0.65; 95% CI 0.63-0.68; P < .001) and receipt of oral anticoagulation (black vs white: AHR 0.94; 95% CI 0.92-0.95; P < .001; Hispanic vs white: AHR 0.94; 95% CI 0.93-0.97; P < .001; female vs male: AHR 0.93; 95% CI 0.93-0.94; P < .001).
Race and sex appear to have a significant effect on the health care provided to this cohort of Medicare beneficiaries diagnosed with AF. Possible explanations include racial differences in access, patient preferences, treatment bias, and unmeasured clinical characteristics.
IMPORTANCE: Cirrhosis is associated with hemorrhagic and thrombotic extrahepatic complications. The risk of cerebrovascular complications is less well understood. OBJECTIVE: To investigate the ...association between cirrhosis and various stroke types. DESIGN, SETTING, AND PARTICIPANTS: We performed a retrospective cohort study using inpatient and outpatient Medicare claims data from January 1, 2008, through December 31, 2014, for a random 5% sample of 1 618 059 Medicare beneficiaries older than 66 years. EXPOSURES: Cirrhosis, as defined by a validated diagnosis code algorithm. MAIN OUTCOMES AND MEASURES: The primary outcome was stroke, and secondary outcomes were ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage as defined by validated diagnosis code algorithms. RESULTS: Among 1 618 059 beneficiaries, 15 586 patients (1.0%) had cirrhosis (mean SD age, 74.1 6.9 years; 7263 46.6% female). During a mean (SD) of 4.3 (1.9) years of follow-up, 77 268 patients were hospitalized with a stroke. The incidence of stroke was 2.17% (95% CI, 1.99%-2.36%) per year in patients with cirrhosis and 1.11% (95% CI, 1.10%-1.11%) per year in patients without cirrhosis. After adjustment for demographic characteristics and stroke risk factors, patients with cirrhosis had a higher risk of stroke (hazard ratio HR, 1.4; 95% CI, 1.3-1.5). The magnitude of association appeared to be higher for intracerebral hemorrhage (HR, 1.9; 95% CI, 1.5-2.4) and subarachnoid hemorrhage (HR, 2.4; 95% CI, 1.7-3.5) than for ischemic stroke (HR, 1.3; 95% CI, 1.2-1.5). CONCLUSIONS AND RELEVANCE: In a nationally representative sample of Medicare beneficiaries, cirrhosis was associated with an increased risk of stroke, particularly hemorrhagic stroke. A potential explanation of these findings implicates the mixed coagulopathy observed in cirrhosis.
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