American Heart Association

Monthly Archives: May 2016

FLAIR Vascular Hyperintensities in Bordezone Strokes

Allison E. Arch, MD

Kim and colleagues investigated the clinical significance of FLAIR vascular hyperintensities in watershed strokes, and they tried to predict poor prognosis using these FLAIR changes as a marker of impaired hemodynamics.

Watershed, or borderzone, strokes represent 10% of all ischemic infarcts. The authors of this study defined 2 types of borderzone strokes: internal borderzone infarcts (IBZ), which are lesions between the deep and superficial perforating arterial territories of the MCA, and cortical borderzone infarcts (CBZ), which are between the MCA/ACA or the MCA/PCA territories. A patient was then considered FLAIR-positive he had 2 or more FLAIR vascular hyperintensities in his MCA territory on MRI, which were thought to have occurred prior to the stroke.

Eighty-seven consecutive patients with acute borderzone strokes were identified, 62 with CBZ and 55 with IBZ. Thirty of all included stroke patients were considered FLAIR-positive. The authors found that FLAIR vascular hyperintensities were associated with a more severe clinical presentation and a poorer clinical prognosis in patients with CBZ strokes, but not in patients with IBZ strokes. They concluded the presence of FLAIR vascular hyperintensities, “may help to identify CBZ-infarcted patients who require close observation and hemodynamic control.”
Their findings are interesting. The authors noted that the presumed pathogenesis of watershed strokes is microembolization in combination with hemodynamic disturbance. However, in patients with FLAIR vascular hyperintensities on MRI, there may be an additional hemodynamic-compromised insult during the stroke, which then leads to poorer outcomes. Kim and colleagues pointed out that in the CBZ group, those who had FLAIR vascular hyperintensities had similar sized DWI lesions to those patients who did not have FLAIR lesions. However, there were significant perfusion differences between the FLAIR-positive and FLAIR-negative groups, lending support to the concept that FLAIR vascular hyperintensities on MRI may signify that the patient is more influenced by hemodynamic instability than his FLAIR-negative counterpart.

It is unclear why this would be on the case in CBZ strokes but not in IBZ strokes. Further investigations are needed to help elucidate the importance of hemodynamics in borderzone strokes. 
By |May 31st, 2016|diagnosis and imaging|Comments Off on FLAIR Vascular Hyperintensities in Bordezone Strokes

Clinical Implications and Determinants of Left Atrial Mechanical Dysfunction in Patients with Stroke

Peggy Nguyen, MD

Kim D, Shim CY, Hong G-R, Kim M-H, Seo J, Cho IJ, et al. Clinical Implications and Determinants of Left Atrial Mechanical Dysfunction in Patients With Stroke. Stroke. 2016

Cardiovascular evaluation is an important part of the evaluation of the stroke patient, in part due to its use to diagnose cardioembolic etiologies of stroke, but also to assess for risk of future events. Left atrial enlargement has been associated with recurrent and first episodes of stroke, even in cases where dysrhythmias are not present; however, the mechanism by which this occurs is not well understood. Here, the authors use TTE with speckle tracking imaging to (1) assess enlargement and impaired mechanical function of the left atrium to define the risk of cardioembolism in stroke patients and (2) define the major determinants of left atrial mechanical dysfunction in these patients.

Two hundred forty-eight patients, derived from a larger study population of 316 acute ischemic stroke patients, who were referred for TTE and TEE, were analyzed. All patients underwent routine TTE, a TEE, as well as 2D speckle tracking echocardiography of the left atrium. Left atrial function was defined by the global left atrial longitudinal strain (LALS) and patients were divided into four groups for analyses: Group 1 – small LA with preserved LALS, Group 2 – large LA with preserved LALS, Group 3 – small LA with impaired LALS, and Group 4 – large LA with impaired LALS. Patients with large LA but impaired function (LALS) were significantly older than the other groups and experienced higher frequency of embolic strokes. 

The authors delve deep into the relationship between echo parameters of LA size and function. A global LALS less than 11.5% was found to be more predictive of a LA or LA appendage thrombus than LA volume index. Both global LALS and LA volume index were predictive of parameters which are suggestive of thrombus formation (and therefore, cardioembolic stroke risk), such as decreased LAA emptying velocity < 20 cm/s and complex aortic plaque. Left atrial function is independently correlated with age, LV function, LA volume index, and aortic stiffness.

The global LALS assessed using 2D speckle tracking imaging on TTE, being predictive of parameters suggestive of thrombus formation and being predictive of thrombus itself, provides an additional measurement which we can use to stratify patients, which can be of particular utility for patients who cannot tolerate a TEE. The presence of impaired global LALS may not be sufficient in of itself to warrant anticoagulation without further investigation, but it should prompt further studies, either the more invasive TEE or cardiac CT or MRI, which is not as widely available. 
By |May 24th, 2016|clinical|Comments Off on Clinical Implications and Determinants of Left Atrial Mechanical Dysfunction in Patients with Stroke

Validating Functional Outcome Prediction Models in Acute Ischemic Stroke: Testing the ASTRAL and DRAGON Scores

Danny R. Rose, Jr., MD

Cooray C, Mazya M, Bottai M, Dorado L, Skoda O, Toni D, et al. External Validation of the ASTRAL and DRAGON Scores for Prediction of Functional Outcome in Stroke. Stroke. 2016

Given that functional outcome is one of the most commonly used parameters in studying acute stroke treatment, developing accurate prognostication scores would greatly facilitate treatment decisions and improve communicating expectations to patients and families. Cooray et al. sought to validate the two most recently developed scores designed to predict functional outcome at three months, one studied in unselected acute stroke patients (ASTRAL) and the other in acute stroke patients treated with iv-tPA (DRAGON) using the SITS-International Stroke Thrombolysis Register (ISTR), a  global stroke thrombolysis database. Outcomes were dichotomized into modified Rankin Scale (mRS) 0-2 and 3-6 as were done in both of the initial studies, and the area under the curve (AUC) of the receiver operating characteristic (ROC) was used in both scores to assess the overall predictive and discriminative performance.

The ASTRAL score was developed in a single center stroke cohort using multivariate logistic regression analysis. It consists of 6 clinical parameters: age at stroke onset (1 point per 5 years), baseline National Institutes of Health Stroke Scale (NIHSS) score (1 point per NIHSS point), time from symptom onset to admission > 3 hours (2 points), any stroke-related visual field defect (2 points), acute blood glucose >7.3 or <3.7 mmol/L (1 point) and decreased level of consciousness based on item 1a on the NIHSS (3 points). A total of 36,131 iv-tPA treated patients with complete data for the ASTRAL score were registered in the SITS-ISTR database. The main differences between the SITS-ISTR and ASTRAL cohorts were higher mean baseline stroke severity (NIHSS 12 vs 9) and a lower proportion of functional independence at 3 months in SITS, which is likely explained by the higher severity. The AUC-RPC value for functionally dependent outcome (mRS 3-6) of the ASTRAL score using this cohort was 0.790 (95% CI 0.786-0.795). Over the rante of scores, the largest discrepancy between the observed and predicted outcome was found to be 11%.

The DRAGON score was developed in a single center cohort of acute ischemic stroke patients treated with iv-tPA using similar statistical design to the ASTRAL score. It is a 10 point scale and the included parameters are hyperdense cerebral artery sign (1 point) and early infarct signs (1 point) on baseline CT, pre-stroke mRS score >1 (1 point), age (<65 years = 0 points, 65-79 years = 1 point, >80 years ≥ 2 points), acute blood glucose >8 mmol/L (1 point), time from symptom onset to treatment >90 min (1 point) and NIHSS score (0-4 = 0 points, 5-9 = 1 point, 10-15 = 2 points and >15 = 3 points). A total of 33,716 iv-tPA treated patients with complete data for the DRAGON score were registered in the SITS-ISTR database. The main differences between the SITS and DRAGON cohorts were higher median baseline stroke severity (NIHSS 12 vs 9), lower proportion of early infarct signs (16.5% vs 30.6%) and higher onset-to-treatment time in the SITS cohort. The AUC-ROC value for functionally dependent outcome on the DRAGON score using the SITS-ISTR cohort was 0.77 (95% CI 0.769-0.779). The largest discrepancy between observed and predicted outcome was close to 17%.

Despite the limitations of using a retrospective analysis, the authors’ validation of the ASTRAL and DRAGON scores suggest an acceptable prognostic value for both. Despite being designed and validated using an unselected cohort that included thrombolysed and non-thrombolysed patients, the ASTRAL score showed a similar discriminative performance to the DRAGON score in this study. Future studies involving these scores would benefit from collecting data prospectively and including patients receiving endovascular therapy.
By |May 23rd, 2016|clinical|1 Comment

Predicting Large Vessel Occlusions in Ischemic Stroke Patients: Search for the Holy Scale

Ilana Spokoyny, MD
If a scale existed that could accurately predict the presence of large vessel occlusion (LVO), it would be extremely useful in triaging patients to either primary or comprehensive stroke centers (CSCs). For patients with LVO who are candidates for endovascular therapy, every minute is critical. Time lost by triaging these patients to primary stroke centers (PSCs) without endovascular capability is time and brain lost. Unfortunately, the range of stroke scales is wide and score cutoffs are inconsistent, and data on their predictive value for detecting LVO is limited. 

The authors of this study assessed 13 different clinical scales for their ability to predict LVO. The cutoff score for each scale which was associated with an under-10% false negative rate (FNR) was also calculated. The false negative rate would include patients with LVO who were not detected by the score cutoff, and so this number would ideally be minimal. Of over 1000 acute stroke patients seen from 2008-2015, about one-third had large artery occlusion (ICA, M1, or basilar). Patients transferred from a primary stroke center for endovascular therapy were excluded, as the authors mention this would have led to too high a prevalence of large vessel occlusions.

The scales included were: modified NIHSS (mNIHSS), 3-item stroke scale (3I-SS), Rapid Arterial oCclusion Evaluation Scale (RACE), Cincinnati Prehospital Stroke Scale (CPSS), Cincinnati Prehospital Stroke Severity Scale (CPSSS), Maria Prehospital Stroke Scale (MPSS), shortened versions of the NIHSS (sNIHSS-1, sNIHSS-5, sNIHSS-8), abbreviated NIHSS (aNIHSS), out-of hospital NIHSS (OoH-NIHSS), retrospective NIHSS profiles (rNIHSS: A to F), and Recognition of Stroke in the Emergency Room (ROSIER). The NIHSS was calculated for each patient on admission (median of 7), and the remaining stroke scale scores were retrospectively calculated from NIHSS score components. The published accepted cutoffs for each score were used to assess predictive value for LVO, and if there was not a published value, the cutoff which maximized the sum of specificity and sensitivity for LVO was used. 

The scores with the highest accuracy were NIHSS (11 and over) and RACE (5 and over), which had 79% accuracy, but these cutoffs were associated with false negative rates (FNR) around 30%. Using NIHSS >= 11 as a cutoff in this cohort would have led to sending 35% of the cohort to a CSC, but 27% of LVO patients would have been inappropriately triaged to primary stroke centers when they should have been sent to a CSC. This false negative rate of 27% falls in the published range for NIHSS >= 11, which has been reported between 12-35%. 

Arguably, it is worse to have a high FNR than a high FPR. A high FNR means time (and brain) lost, while a high FPR means overburdening the CSCs (but not necessarily worse care for patients). To achieve a FNR under 10%, the cutoff scores had to be quite low – the NIHSS cutoff was 5, mNIHSS was 3, RACE was 1, and Cincinnati Prehospital Stroke Severity Scale (CPSSS) was zero. As expected, using published cutoff scores (such as NIHSS 11) for triage would inappropriately send about 25% of patients with LVO to centers without endovascular capability. If, however, we used the calculated cutoffs which reduced the FNR to under 10% (such as NIHSS of 5), 60% of patients would have been sent to a comprehensive stroke center, 46% of whom would have been futile transfers, overburdening the system. 

Limitations noted by the authors include the changing cutoff score for LVO as time passes, the lower predictive value of NIHSS for LVO in the posterior circulation, and the lack of training of emergency medical teams in performing the NIHSS. The simpler scales seemed to be a solution to address the complexity of the NIHSS, but these scores posed similar problems in this analysis as did the NIHSS. This important study highlights the pitfalls of using the existing clinical scales to predict LVO. The authors recommend that intracranial artery imaging should be performed in all stroke patients presenting within 6 hours of onset, since the scores cannot be reliably used. They bring up the idea of a mobile stroke unit, which could be used to image in the field and triage patients. Additionally, biomarkers and TCDs have potential roles in the future for detecting LVO stroke patients in the field. This study is limited by its population, in that the patients were all admitted to a CSC and had a diagnosis of stroke. A study on the predictive value of stroke scales performed in the prehospital setting would provide real-world data along with the ability to quantify the role of the examiner’s proficiency with the stroke scale. In the meantime, optimizing the transfer process to swiftly identify and transport LVO patients from PSCs to a CSC with endovascular capability is critical to ensure that our patients get the best stroke care possible.

By |May 20th, 2016|clinical|Comments Off on Predicting Large Vessel Occlusions in Ischemic Stroke Patients: Search for the Holy Scale

Structured Nurse Practitioner Transitional Stroke Program Reduced 30-day Readmissions after Stroke

Qing Hao, MD, PhD

After discharge from hospital, strokes survivors usually are faced with physical and cognitive impairments, complex medication regimen, new diagnosis of other medical illness and need of social support which all significantly affect stroke recovery and readmissions due to stroke related complications or other medical conditions. The experience from non-stroke patients that addressed the cumulative complexity (patients’ demands and capacity) have demonstrated effective interventions for reducing 30-day readmissions, however, the transitional care models for stroke patients have not been well established. Condon and colleagues developed a model of Transitional Stroke Clinic (TSC) led by nurse practitioner(NP) and investigated its role in reducing readmissions by conducting an observational quality improvement study in a single academic, tertiary referral center.

Two phases of transitional care model were implemented from 10/2012 to 09/2015: 

Over 3 years, among 1421 stroke or TIA patient who were discharged home, 510 patient were enrolled into the transitional care model with a mean age of 65 and median NIHSS of 2. A lower TSC show rate was observed in patients readmitted within 30 days (60.8% vs 76.3% not readmitted; p=0.021); a similar trend was noticed in those readmitted within 90 days (67.5% vs 76.4%; p=0.088).
Multivariate analysis showed the TSC visits independently reduced the 30-day readmission by 48% (OR 0.518, 95% CI 0.272, 0.986; p=0.045), and the reduction was not significant for 90-day readmission. Prior stroke and multiple chronic conditions were associated with both 30-day and 90-day readmission.  Other factors that significantly affected 90-day readmission were prior hospitalization, and male gender.
Interestingly, compared with phase I, the phase II protocol made more follow-up phone calls earlier and were able to see all patient in TSC earlier using a structured clinic visit template (although the details of structured vs not structured were not specified), the rate of TSC visit and readmissions in 30 day and 90 day did not differ significantly in two phases.  This is probably because the readmission mainly occurred in high-risks patients, by focusing on this group of population, phase I protocol was able to effectively reduce the readmission rate. In addition, both phases followed the concept of cumulative complexity and spent significant effort on education, coordinating care with referral to therapy and community services, addressing social needs and handing off the care to the primary care which are also important interventions that enhanced patient care.  The phase I model that requires less time and resources may be preferred in future practices, but further investigations are needed. 
With a few limitations (e.g., not covering the patients who were discharged to rehab or skilled nursing facilities with higher NIHSS and who may be at higher risks of readmission, possibility of underestimation of readmission rate), this study showed promising result that early evaluation in NP-led structured transitional clinic was able to reduce readmission at 30 day by about 50% in stroke patients who were discharged home.  We are very glad that a pragmatic clinical trial based on these results is being implemented in North Carolina and we look forward to the standardized, effective and practical transitional care models for stroke survivors.
By |May 19th, 2016|outcomes|Comments Off on Structured Nurse Practitioner Transitional Stroke Program Reduced 30-day Readmissions after Stroke

Inverse Relationship Between Leukocyte Count and ICH Hematoma Expansion

Alexander E. Merkler, MD 
Intracerebral hemorrhage (ICH) is a catastrophic type of stroke with a one-month mortality of 40%. Although initial ICH volume is the strongest predictor of mortality, hematoma expansion is a potentially modifiable risk factor that correlates well with both functional outcome and death and occurs in up to 40% of patients with ICH. Research has therefore focused on 1) identification of factors that predict hematoma expansion and 2) methods to reduce hematoma expansion. 

The relationship between neuroinflammation, WBC count, and ICH pathophysiology is complex with prior studies suggesting that a higher WBC count predicts worse outcome. On the other hand, acute leukocytosis is associated with coagulation and consequently may lead to an arrest hematoma expansion in ICH. In this study, Dr. Morotti et al. evaluate the relationship between admission leukocytosis and hematoma expansion in patients with ICH. Hematoma expansion was defined as an increase in ICH volume of >30% or >6mL. WBC count was analyzed in quartiles.  
The authors retrospectively evaluated 1302 prospectively collected patients with non-traumatic ICH. Of these patients, 15.9% experienced a hematoma expansion. The median WBC count on admission was 9200 cells/uL. Overall, after adjustment for demographics and other risk factors for hematoma expansion, higher admission WBC was independently associated with a reduced risk of hematoma expansion (OR for 1000 cells increase 0.91, 95% CI 0.86-0.96). In secondary analyses, the authors evaluated the effect of WBC subtypes on hematoma expansion; higher admission neutrophil count was associated with a lower risk of hematoma expansion (OR for 1000 cells increase 0.90, 95% CI 0.85-0.96) whereas higher admission monocyte count was associated with hematoma expansion (OR for 1000 cells increase, 2.71, 95% CI 1.08-6.83). Lymphocyte count was not associated with hematoma expansion.
Despite certain limitations such as lack of information regarding baseline infectious/inflammatory conditions that may have affected admission WBC counts, the study is certainly suggestive that acute inflammation plays a role in modulating the coagulation cascade following ICH. Perhaps identification of methods to acutely alter neuroinflammation may prove to be a salient method to halt hematoma expansion.
By |May 18th, 2016|clinical|Comments Off on Inverse Relationship Between Leukocyte Count and ICH Hematoma Expansion

Declining Rate of IV Heparin Use in Acute Ischemic Stroke in Korea

Jay Shah, MD

Chung J-W, Kim BJ, Han M-K, Ko Y, Lee S, Kang K, et al. Impact of Guidelines on Clinical Practice: Intravenous Heparin Use for Acute Ischemic Stroke. Stroke. 2016

IV heparin has been available since the 1940’s and its role in ischemic stroke has been constantly debated. IV heparin has a clear indication in cardiac ischemia and many presume its efficacy should translate in acute ischemic stroke as well. However, numerous studies have failed to show benefit and American Stroke Association does not recommend anticoagulation acutely. Because heparin has been available for numerous years, there is little information on contemporary use and this study evaluated recent IV heparin trends across 12 hospitals in Korea in a 5 year span from 2008-2013.

Data was obtained from an acute stroke registry that included consecutive stroke patients. Information regarding stroke characteristics, recanalization treatment and antithrombotic treatment during hospitalization and post-discharge were collected. In total, 23,425 patients were included in the study. In the study period, the rate of recanalization treatment increased. Use of IV heparin decreased consecutively during the study period with use of 4.3% in 2013 compared to 9.7% initially. In the small proportion of patients that were treated with IV heparin, atrial fibrillation was associated with more frequent use.

This study shows declining rates of IV heparin use in acute ischemic stroke. This coincides with a 2009 publication of a Korean stroke clinical practice guideline and supports adherence to guidelines by neurologist. Interestingly, atrial fibrillation was associated with use of IV heparin. Typically, cardioembolic strokes are generally larger and acute anticoagulation is not pursued due to hemorrhage risk. Furthermore, subsequent short-term stroke risk following a cardioembolic stroke is relatively lower (unlike large vessel disease) and delaying anticoagulation until hemorrhage risk is lower has become the standard practice. Use of IV heparin is sometimes reserved for patients with critical carotid stenosis awaiting carotid endarterectomy but such decisions are made on case-by-case basis. This study further affirms that clinical guideline recommendations impact clinical decision making and have the ability to impact outcomes as well.

By |May 10th, 2016|treatment|Comments Off on Declining Rate of IV Heparin Use in Acute Ischemic Stroke in Korea

Limited Meta-analysis Suggests Patients with Asymptomatic Carotid Occlusion are at Low Risk of Ipsilateral Stroke, High Risk of Non-stroke Mortality

Danny R. Rose, Jr., MD

Hackam DG. Prognosis of Asymptomatic Carotid Artery Occlusion: Systematic Review and Meta-Analysis. Stroke. 2016

Although carotid artery occlusion is estimated to account for 10-15% of all ischemic strokes and transient ischemic attacks, there is little consensus regarding the long-term prognosis of asymptomatic carotid artery occlusion (ACAO), which is most often found incidentally during workup for cerebrovascular disease. Hackam sought to shed light on this issue by conducting a systematic review of studies that enrolled patients with ACAO that collected follow-up information on the occurrence of ipsilateral ischemic stroke as an outcome measure. 

A total of 13 studies were included in the meta-analysis. The studies enrolled 4406 patients, 718 of whom had ACAO (16%). The median age of patients with ACAO was 67 and 23% were female.  All but two studies used ultrasound to define ACAO diagnostically; however the use of angiography was high overall (66% of subjects). Median follow-up was 2.80 years, with an annual ipsilateral stroke rate of 1.3% (95% CI 0.4-2.1%). Two-year and 5-year rates of stroke were 2.5% and 6.3%, respectively. There was substantial heterogeneity in the base estimate (I2=53%). Annual total stroke was 2.0% (95% CI 0.9-3%; I2=40%). 

Eleven studies reported on ipsilateral TIA, with an annual rate of 1% (95% CI 0.3-1.8% I2=40%) and an annual total TIA rate of 3.0% (95% CI 1.9-4.1% I2=0).  Seven studies reported mortality, with an annual rate of death of 7.7% with marked heterogeneity (95% CI 4.3-11.2% I2=83%). Six studies reported stroke-related death, with an annual rate of 1.1% (95% CI 0.07-2.1% I2=63%). Cardiac death was more frequent at 3.3% per year (95% CI 1.2-5.4% I2=83%). In the prescribed subgroup analysis, studies published on or after the year 2000 had a statistically significantly lower aggregate ipsilateral stroke rate than studies published before 2000 (0.9% to 1.5%, p=0.003). Adjusting for publication bias suggested a revised ipsilateral stroke rate of 0.3% per year (95% CI -0.4 to 1.1%).

Although the study was limited by significant heterogeneity, it suggests that the risk from ACAO is low. With subgroup analysis of studies published after the advent of contemporary medical management of vascular disease and trim-and-fill analysis suggesting a lack of studies published to the left of the mean, the rate is likely lower than the 1.3% per year grand mean that was reported. However, the annual risk of death was quite high (7.7%), likely attributable to ACAO being a surrogate marker of systemic atherosclerosis, possibly carrying a higher risk of cardiac death. 

Further study of this population is warranted. Potential avenues for future study would include a prospective cohort of patients with medically managed carotid stenosis and occlusion with matched controls, following a variety of vascular outcomes. Perfusion or more in-depth angiographic imaging to identify a potential subset of patients at higher risk of stroke could also be of use.  
By |May 9th, 2016|prevention|Comments Off on Limited Meta-analysis Suggests Patients with Asymptomatic Carotid Occlusion are at Low Risk of Ipsilateral Stroke, High Risk of Non-stroke Mortality

Heart Rate Variability and Incident Stroke Risk in the Atherosclerosis Risk in Communities Study

Neal S. Parikh, MD
In this issue of Stroke, Amber Fyfe-Johnson and colleagues describe their investigation of the association between heart rate variability (HRV) and incident stroke risk in the Atherosclerosis Risk in Communities (ARIC) Study cohort.

They argue that autonomic nervous system (ANS) dysfunction, as reflected by HRV, may be associated with cardiovascular mortality, coronary heart disease, and mortality in stroke survivors. ANS dysfunction may be associated with dysregulated cerebrovascular autoregulation and blood pressure.

ARIC participants were assessed by EKG for HRV by four measures at visit 1 (1987-1989) and followed through December 31, 2011 for incident stroke by telephone ascertainment, hospital discharge diagnosis review, and state death registry review. Covariates, collected at the index visit and again at visit 4 (1996-1998), included: age, sex, race, smoking/alcohol use, physical activity, body mass index, blood pressure, blood lipids, and diabetes. Patients taking medications that modify HRV (beta-blockers, anti-arrythmics, calcium channel blockers, digoxin) and those with prevalent stroke, coronary disease, or heart failure were excluded.  

Cox proportional hazards models were used to calculate hazard ratios for the relationship between each quintile of HRV measures and stroke.

Of 12,550 ARIC participants, 816 (6.5%) had stroke. Crude cumulative stroke incidence was higher in patients with the lowest HRV quintile (compared to the highest quintile). However, after adjustment for covariates, associations between HRV and stroke risk were attenuated and did not meet statistical significance. In analyses restricted to participants with diabetes, stroke risk was higher in the lowest HRV quintile, but this association was only statistically significant when testing one of four HRV measures (HR 2.0, 95% confidence interval, 1.1-4.0).

The authors conclude that there may be an association between low HRV and incident stroke in populations already at risk – patients with diabetes. Whether this association would withstand adjustment for an expanded list of cardiovascular risk factors in a modern cohort is unclear. However, the importance of identifying simple indicators of stroke risk such as HRV cannot be overstated. 
By |May 6th, 2016|epidemiology and genetics|Comments Off on Heart Rate Variability and Incident Stroke Risk in the Atherosclerosis Risk in Communities Study

Hematoma Shape, but not Density, is Predictive of Clinical Outcomes in ICH from the INTERACT2 Study

Peggy Nguyen, MD

Delcourt C, Zhang S, Arima H, Sato S, Al-Shahi Salman R, Wang X, et al. Significance of Hematoma Shape and Density in Intracerebral Hemorrhage: The Intensive Blood Pressure Reduction in Acute Intracerebral Hemorrhage Trial Study. Stroke. 2016

In patients with intracerebral hemorrhage (ICH), parameters such as hematoma volume has been shown to be predictive of hematoma growth and poor clinical outcomes; other characteristics, such as shape and density have been shown to be associated with growth, but evidence demonstrating its predictive value for clinical outcomes has been limited. Here, the authors used data from the INTERACT2 study and evaluated the association of hematoma shape (irregularity) and density (heterogeneity) on 90-day death or disability.

2066 subjects were included for analysis, with 946 subjects having irregular hematomas and 781 subjects having heterogenous hematomas. Of note, there were significant differences between patients with irregular versus regular hematomas, including older age, more severe neurological status, and lobar hemorrhages in the former group, among others. Similarly, patients with heterogenous hematomas, compared to those with homogenous hematomas, were more likely to have lobar hematomas and less likely to have intraventricular extension. Larger hematomas were more likely to be irregular and heterogenous, and this is likely reflected in the differences between each group and their comparators. In addition, the decision to withdraw treatment was more likely to be made among patients with irregular hematomas and among patients with heterogenous hematomas, when compared to their counterparts.

Nevertheless, when controlled for factors such as age, systolic blood pressure, NIHSS, prior use of antithrombotics, location and volume of baseline hematoma, IVH, and decision to withdraw active treatment, irregular hematomas were found to be independently associated with the primary outcome of risk of death or major disability at 90-days (OR 1.60) and major disability at 90 days (OR 1.60) although not with death alone. Heterogenous density did not predict the primary outcome, nor individually, the outcome of death nor disability.

This study is significant in providing some evidence for imaging markers which may be predictive of clinical outcomes in the emergent period, allowing clinicians to adjust decision making and provide better informed counseling to patients and their families.   

By |May 4th, 2016|hemorrhage|Comments Off on Hematoma Shape, but not Density, is Predictive of Clinical Outcomes in ICH from the INTERACT2 Study