Abstract TP177: Preoperative Functional Status and Type of Surgery Influences Postoperative Stroke Risk: analysis from the Nationwide Surgical Quality Initiative Program

Introduction: Post-operative stroke (POS) is associated with vascular and cardiac surgery, but this finding has mainly been reported among populations receiving vascular and cardiac procedures. We investigated the association between type of surgery and risk of POS in a large, generalizable inpatient cohort from the American College of Surgeons National Surgical Quality Initiative Program (NSQIP) database.

Hypothesis: Cardiac and vascular procedures are associated with an increased risk of POS.

Methods: We identified patients that underwent surgery between the years of 2000 and 2010. Our primary outcome was POS within 30 days of surgery. Using a hierarchical model adjusted for age, race, sex, medical comorbidities and dichotomized functional status, we assessed for clustering between type of surgery and POS. We then determined risk factors for POS while adjusting for clustering. Each surgical type was compared against all other surgical types.

Results: We identified 729,886 patients, of whom 2,703 (0.3%) developed POS. In the hierarchical analysis, cardiac surgery (incidence rate ratio (IRR) 6.38, 95%CI 5.37-7.55), vascular surgery (IRR 4.41, 95%CI 4.08-4.76), and neurosurgery (IRR 2.05, 95%CI 1.69-2.48) were associated with increased risk of POS. The only patient-level factor associated with surgery type was poor preoperative functional status. Accounting for clustering, patients with poor pre-operative functional status (OR 4.11, 95%CI 3.60-4.69), history of stroke (OR 2.35 95%CI 2.06-2.69), history of transient ischemic attack (OR 2.49 95%CI 2.19-2.83), active smoking (OR 1.20, 95%CI 1.08-1.32), and COPD (OR 1.39 95%CI 1.21-1.59) were at higher risk of POS. There was no interaction between preoperative functional status and type of surgery.

Conclusions: In a large cohort of surgical inpatients, we found that the risk of POS was significantly associated with cardiac, vascular, and neurosurgical procedures. Certain patient populations, such as those with a dependent pre-operative functional status, may be at a higher risk of POS and may be more likely to undergo cardiac, vascular, or neurosurgical procedures. Further studies are needed to elucidate the relationship between pre-surgical functional status and type of surgery.

Abstract 134: Postoperative Atrial Fibrillation and the Short-term Risk of Ischemic Stroke

Introduction: We have recently shown an association between new-onset postoperative atrial fibrillation (AF) and the long-term risk of ischemic stroke after noncardiac surgery. However, the degree of stroke risk with AF in the postoperative setting remains unclear.

Hypothesis: New-onset postoperative AF is associated with an increased risk of ischemic stroke in the 30 days after surgery.

Methods: Administrative claims data from all discharges at nonfederal acute care hospitals in California, New York, and Florida were used to identify patients who underwent inpatient surgery in 2007-2012. Our predictor variable was new-onset AF, defined using validated ICD-9-CM diagnosis and present-on-admission codes. Patients with prior stroke or AF were excluded. The outcome was postoperative stroke, defined as ischemic stroke occurring within 30 days of surgery. Cox proportional hazards analysis was used to examine the association between postoperative AF and stroke while adjusting for demographics and vascular risk factors. In sensitivity analyses, we limited the outcome to stroke occurring after discharge but within 30 days of surgery. Cardiac and noncardiac surgeries were analyzed separately.

Results: Among 7,139,472 patients with inpatient surgery, 102,831 (1.44%) developed postoperative AF and 17,117 (0.24%) developed a postoperative stroke. After noncardiac surgery, the 30-day cumulative risk of stroke was significantly higher in those with postoperative AF (2.07%) than those without AF (0.18%). This difference was significant after adjustment for demographics and potential confounders (hazard ratio [HR], 4.3; 95% CI, 4.1-4.6). After cardiac surgery, postoperative AF was also associated with an increased cumulative risk of stroke (2.27%) compared to those without AF (1.17%), but the strength of association (HR, 1.8; 95% CI, 1.6-1.9) was less marked than in the setting of noncardiac surgery ( P value for interaction <0.001). Postoperative AF was associated with stroke occurring after discharge and within 30 days of noncardiac surgery (HR, 1.9; 95% CI, 1.6-2.3), but not cardiac surgery (HR, 1.1; 95% CI, 0.9-1.3).

Conclusions: Postoperative AF is associated with an increased short-term risk of stroke after noncardiac surgery.

Abstract WP192: The Association Between Carotid Artery Atherosclerosis and Silent Brain Infarction: a Systematic Review and Meta-analysis

Introduction: Silent brain infarctions (SBI) are asymptomatic lesions whose presence is associated with a two-fold increased risk of future stroke. Though carotid atherosclerosis is responsible for ∼20% of ischemic strokes, the strength of association between carotid disease and SBI is unclear based on estimates from individual studies.

Hypothesis: We hypothesized that a synthesis of the existing literature would show that two separate manifestations of carotid atherosclerosis, carotid intima-media thickening (IMT) and luminal stenosis, are associated with SBI.

Methods: We searched multiple online literature databases from their inception to April 2015. Articles were included if they reported an association between MRI defined SBI and carotid IMT or stenosis, excluding SBI evaluation after a procedure. The association between SBI and IMT or stenosis was estimated using pooled random-effects (RE) standard mean difference (SMD) or odds ratio, respectively.

Results: We pooled 6 IMT studies reporting on 1434 subjects with SBI and 5058 subjects without SBI. Subjects with SBI had a larger mean IMT compared to subjects without SBI (pooled RE SMD, 0.36; 95% CI, 0.21 to 0.51; P<0.0001, Figure Panel A). We pooled 9 carotid stenosis studies reporting on 11,177 subjects (1839 subjects with and 9338 subjects without carotid stenosis). In total, 141 (22.5%) of the subjects with carotid stenosis had SBI, while 1568 (16.8%) of the subjects without carotid stenosis had SBI. Our pooled RE analysis showed a significant positive relationship between carotid stenosis and SBI (OR, 2.62; 95% CI, 2.04 to 3.36; P<0.0001, Figure Panel B).

Conclusions: Both carotid IMT and stenosis are significantly associated with the presence of SBI. Patients with SBI and carotid atherosclerosis may represent a group at higher risk of clinically overt stroke and who may therefore benefit from more intensive stroke prevention measures.

Abstract TP186: Lack of Insurance is Associated with Increased Risk of Intracerebral Hemorrhage

Introduction: Effective management of hypertension is essential for the prevention of intracerebral hemorrhage (ICH), but disparities in access to healthcare create a barrier to achieving this aim.

Hypothesis: Among patients presenting for emergency care of hypertension, lack of insurance is associated with a higher risk of subsequent ICH.

Methods: We performed a retrospective cohort study using administrative data from all acute care hospitalizations and emergency department (ED) visits in California, Florida, and New York between the years of 2005 and 2011. Our cohort comprised patients discharged from the ED with a primary diagnosis of hypertension, defined as International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes 401-405. Patients with a prior or concomitant diagnosis of cerebrovascular disease (ICD-9-CM codes 430-438) were excluded. Patients 65 years and older were excluded because these patients often have access to Medicare insurance. Our predictor variable was lack of insurance, as compared with Medicaid or commercial insurance. Patients were followed for the primary outcome of ICH, defined using previously validated ICD-9-CM codes. Survival statistics were used to calculate the cumulative rate of ICH and Cox proportional hazards analysis was used to assess the association between lack of insurance and development of ICH while adjusting for demographic characteristics and vascular risk factors.

Results: Among 361,019 patients with 3.4 (+/- 1.8) years of follow-up, the cumulative rate of ICH in patients without insurance was 1.03% (95% confidence interval [CI], 0.90-1.18%) as compared to 0.88% (95% CI, 0.80-0.96) in patients with insurance. After adjusting for demographic variables and vascular risk factors, lack of insurance was associated with the development of ICH (hazard ratio, 1.20; 95% CI, 1.07-1.34).

Conclusion: In a large, heterogeneous group of patients presenting for emergency care of hypertension, lack of insurance was associated with an increased risk of ICH after discharge. Further investigation is needed to address the impact of access to healthcare on rates of this disabling disease.

Risk of reintubation in neurosurgical patients

BACKGROUND

Reintubation among neurosurgical patients is poorly characterized. The aim of this study was to delineate the rate of reintubation among neurosurgical patients. In addition, we seek to characterize the patient demographic features, comorbidities, and surgical characteristics that may be associated with reintubation among neurosurgical patients.

METHODS

This is a retrospective cohort study conducted in the setting of hospitals participating in the American College of Surgeons' National Surgical Quality Improvement Program between 2005 and 2010. All adult patients undergoing neurosurgery under general anesthesia were included. Exclusion criteria were preoperative mechanical ventilation or pneumonia prior to surgery. Reintubation was defined as placement of an endotracheal tube or mechanical ventilation within 48 h after surgery.

RESULTS

Among 17,483 eligible patients, 74 (0.42 %; 95 % CI 0.33-0.52 %) required reintubation within 48 h of surgery. In multiple logistic regression, the following were associated with increased risk of reintubation: age >65 years (OR 2.1; 95 % CI 1.3-3.4), preoperative renal failure (OR 2.9; 95 % CI 1.0-8.5), quadriplegia (OR 8.2; 95 % CI 3.3-20.3), COPD (OR 2.1; 95 % CI 1.0-4.3), operative time >3 h (OR 2.9; 95 % CI 1.8-4.8), and higher ASA class (OR per point, 2.1; 95 % CI 1.4-3.1). Spinal surgery was found to be protective relative to cranial neurosurgery or endarterectomy (OR 0.3; 95 % CI 0.2-0.5).

CONCLUSIONS

Reintubation after neurosurgery is associated with older patients with a greater number of comorbidities. In particular, renal, pulmonary, and severe neurologic comorbidities; longer operative duration; and cranial, rather than spinal, pathology were associated with increased risk for reintubation. These findings may be helpful in triage decisions regarding postoperative intensity of care and monitoring.

Patient-Powered Reporting of Modified Rankin Scale Outcomes Via the Internet

BACKGROUND AND PURPOSE

The modified Rankin Scale (mRS) is a common and resource-intensive measure of functional outcome in stroke-related conditions. In this observational prospective cohort feasibility study, mRS scores are generated using a patient-powered online survey and compared to scores obtained by structured telephonic interview.

MATERIALS AND METHODS

Fifty-one patients with subarachnoid hemorrhage (SAH) or their surrogates responded to an online survey following discharge from the hospital. These responses were used to generate an mRS score and then compared to blinded telephonic assessments by trained personnel. A weighted kappa (Kw) with confidence intervals (CIs) was calculated.

RESULTS

The Kw between the patient/surrogate and the trained personnel scores was 0.85 (95% CI, 0.74-0.95, P < .001).

CONCLUSION

This study provides first evidence that patient/surrogate survey responses may be an efficient and reliable alternative to generate mRS scores compared to trained personnel after SAH.

Risk of Stroke After the International Classification of Diseases-Ninth Revision Discharge Code Diagnosis of Hypertensive Encephalopathy

BACKGROUND AND PURPOSE

Although chronic hypertension is a well-established risk factor for stroke, little is known about stroke risk after hypertensive encephalopathy (HE), when neurologic sequelae of hypertension become evident. Therefore, we evaluated the risk of stroke after a diagnosis of HE.

METHODS

We identified all patients discharged from California, New York, and Florida emergency departments and acute care hospitals between 2005 and 2012 with a primary International Classification of Diseases, Ninth Edition, Clinical Modification discharge diagnosis of HE (437.2). Patients discharged with a primary diagnosis of seizure (345.x) served as negative controls, whereas patients with a primary diagnosis of transient ischemic attack (435.x) were positive controls. Our primary outcome was the composite of subsequent ischemic stroke or intracerebral hemorrhage. Kaplan-Meier survival statistics were used to calculate cumulative outcome rates, and Cox proportional hazard analysis was used to examine the association between index disease types and outcomes while adjusting for vascular risk factors.

RESULTS

We identified 8233 patients with HE, 191 091 with seizure, and 308 680 with transient ischemic attack. The 1-year cumulative rate of ischemic stroke or intracerebral hemorrhage after HE was 4.90% (95% confidence interval [CI], 4.45-5.40) when compared with 0.92% (95% CI, 0.88-0.97) after seizure and 4.49% (95% CI, 4.42-4.57) after transient ischemic attack. The risk of intracerebral hemorrhage was significantly elevated in those with HE (hazard ratio, 2.0; 95% CI, 1.7-2.5) but not in those with transient ischemic attack (hazard ratio, 1.0; 95% CI, 0.9-1.1), when compared with seizure patients.

CONCLUSIONS

Patients discharged with a diagnosis of HE face a high risk of future cerebrovascular events, particularly intracerebral hemorrhage.

Risk of Ischemic Stroke after Intracranial Hemorrhage in Patients with Atrial Fibrillation

Background

We aimed to estimate the risk of ischemic stroke after intracranial hemorrhage in patients with atrial fibrillation.

Materials and Methods

Using discharge data from all nonfederal acute care hospitals and emergency departments in California, Florida, and New York from 2005 to 2012, we identified patients at the time of a first-recorded encounter with a diagnosis of atrial fibrillation. Ischemic stroke and intracranial hemorrhage were identified using validated diagnosis codes. Kaplan-Meier survival statistics and Cox proportional hazard analyses were used to evaluate cumulative rates of ischemic stroke and the relationship between incident intracranial hemorrhage and subsequent stroke.

Results

Among 2,084,735 patients with atrial fibrillation, 50,468 (2.4%) developed intracranial hemorrhage and 89,594 (4.3%) developed ischemic stroke during a mean follow-up period of 3.2 years. The 1-year cumulative rate of stroke was 8.1% (95% CI, 7.5–8.7%) after intracerebral hemorrhage, 3.9% (95% CI, 3.5–4.3%) after subdural hemorrhage, and 2.0% (95% CI, 2.0–2.1%) in those without intracranial hemorrhage. After adjustment for the CHA₂DS₂-VASc score, stroke risk was elevated after both intracerebral hemorrhage (hazard ratio [HR], 2.8; 95% CI, 2.6–2.9) and subdural hemorrhage (HR, 1.6; 95% CI, 1.5–1.7). Cumulative 1-year rates of stroke ranged from 0.9% in those with subdural hemorrhage and a CHA₂DS₂-VASc score of 0, to 33.3% in those with intracerebral hemorrhage and a CHA₂DS₂-VASc score of 9.

Conclusions

In a large, heterogeneous cohort, patients with atrial fibrillation faced a substantially heightened risk of ischemic stroke after intracranial hemorrhage. The risk was most marked in those with intracerebral hemorrhage and high CHA₂DS₂-VASc scores.

Association between Liver Disease and Intracranial Hemorrhage

BACKGROUND

Liver disease is common and associated with clinical and laboratory evidence of coagulopathy. The association between liver disease and intracranial hemorrhage (ICH) remains unclear. Our aim was to assess whether liver disease increases the risk of ICH.

METHODS

We performed a retrospective cohort study based on administrative claims data from California, Florida, and New York acute care hospitals from 2005 through 2011. Of a random 5% sample, we included patients discharged from the emergency department or hospital after a diagnosis of liver disease and compared them to patients without liver disease. Patients with cirrhotic liver disease were additionally analyzed separately. Kaplan-Meier survival statistics were used to calculate cumulative rates of incident ICH, and Cox proportional hazard analysis was used to adjust for demographic characteristics, vascular disease, and Elixhauser comorbidities. Multiple models tested the robustness of our results.

RESULTS

Among 1,909,816 patients with a mean follow-up period of 4.1 (±1.8) years, the cumulative rate of ICH after a diagnosis of liver disease was 1.70% (95% confidence interval [CI], 1.55%-1.87%) compared to .40% (95% CI, .39%-.41%) in patients without liver disease (P <.001 by the log-rank test). Liver disease remained associated with an increased hazard of ICH after adjustment for demographic characteristics and vascular risk factors (hazard ratio [HR], 1.8; 95% CI, 1.6-2.0). This was attenuated in models additionally adjusted for general comorbidities (HR, 1.3; 95% CI, 1.2-1.5).

CONCLUSIONS

There is a modest, independent association between liver disease and the risk of ICH.

Atrial Cardiopathy and Cryptogenic Stroke: A Cross-sectional Pilot Study

BACKGROUND

There is increasing evidence that left atrial dysfunction or cardiopathy is associated with ischemic stroke risk independently of atrial fibrillation. We aimed to determine the prevalence of atrial cardiopathy biomarkers in patients with cryptogenic stroke.

METHODS

We included consecutive patients with ischemic stroke enrolled in the New York Columbia Collaborative Specialized Program of Translational Research in Acute Stroke registry between December 1, 2008, and April 30, 2012. Medical records were reviewed and patients with a diagnosis of cryptogenic stroke were identified. Atrial cardiopathy was defined as at least one of the following: serum N-terminal probrain natriuretic peptide (NT-proBNP) level greater than 250 pg/mL, P-wave terminal force velocity in lead V1 (PTFV1) on electrocardiogram (ECG) greater than 5000 µV⋅ms, or severe left atrial enlargement (LAE) on echocardiogram. We compared clinical, echocardiographic, and radiological characteristics between patients with and without atrial cardiopathy.

RESULTS

Among 40 patients with cryptogenic stroke, 63% had at least one of the biomarkers of atrial cardiopathy; 49% had elevated NT-proBNP levels, 20% had evidence of increased PTFV1 on ECG, and 5% had severe LAE. Patients with atrial cardiopathy were more likely to be older (76 versus 62 years, P = .012); have hypertension (96% versus 33%, P < .001), hyperlipidemia (60% versus 27%, P = .05), or coronary heart disease (28% versus 0%, P = .033); and less likely to have a patent foramen ovale (4% versus 40%, P = .007).

CONCLUSION

There is a high prevalence of biomarkers indicative of atrial cardiopathy in patients with cryptogenic stroke. Clinical trials are needed to determine whether these patients may benefit from anticoagulation to prevent stroke.

Non-truncating LIFR mutation: causal for prominent congenital pain insensitivity phenotype with progressive vertebral destruction?

We present a Qatari family with two children who displayed a characteristic phenotype of congenital marked pain insensitivity with hypohidrosis and progressive aseptic destruction of joints and vertebrae resembling that of hereditary sensory and autonomic neuropathies (HSANs). The patients, aged 10 and 14, remained of uncertain genetic diagnosis until whole genome sequencing was pursued. Genome sequencing identified a novel homozygous C65S mutation in the LIFR gene that is predicted to markedly destabilize and alter the structure of a particular domain and consequently to affect the functionality of the whole multi-domain LIFR protein. The C65S mutant LIFR showed altered glycosylation and an elevated expression level that might be attributed to a slow turnover of the mutant form. LIFR mutations have been reported in Stüve-Wiedemann syndrome (SWS), a severe autosomal recessive skeletal dysplasia often resulting in early death. Our patients share some clinical features of rare cases of SWS long-term survivors; however, they also phenocopy HSAN due to the marked pain insensitivity phenotype and progressive bone destruction. Screening for LIFR mutations might be warranted in genetically unresolved HSAN phenotypes.

Potential new uses of non-vitamin K antagonist oral anticoagulants to treat and prevent stroke

BACKGROUND

Non-vitamin K antagonist oral anticoagulant (NOAC) drugs are at least equivalent to warfarin for ischemic stroke prevention in patients with atrial fibrillation and have a lower risk of intracranial hemorrhage. The role of these agents in the prevention and treatment of other types of cerebrovascular disease remains unclear.

METHODS

We reviewed the literature (randomized trials, exploratory comparative studies, and case series) on the use of NOACs in patients with atrial fibrillation, venous thromboembolism, and cerebrovascular disease independent of atrial fibrillation.

RESULTS

The literature on the use of NOACs for treatment and prevention of cerebrovascular disease in patients without atrial fibrillation is sparse. The potential benefit of vitamin K antagonists over antiplatelet agents for primary and secondary prevention in certain subsets of patients with cerebrovascular disease is offset by the increased risk of major and intracranial hemorrhage. Given that NOACs are equivalent to vitamin K antagonists in preventing ischemic stroke and systemic embolism in patients with atrial fibrillation with less bleeding risk, clinical trials are needed to investigate the short- and long-term use of NOACs in populations of patients with other forms of cerebrovascular disease, including those with cryptogenic stroke with or without evidence of patent foramen ovale and low ejection fraction, cervical artery dissection, large artery atherosclerosis, venous thrombosis, and stuttering lacunar stroke.

CONCLUSION

There may be a role for NOACs in stroke prevention and treatment beyond atrial fibrillation. Randomized controlled trials are needed to compare NOACs to current stroke prevention and treatment strategies in certain subgroups of patients with cerebrovascular disease.

Electrocardiographic Left Atrial Abnormality and Risk of Stroke: Northern Manhattan Study

BACKGROUND AND PURPOSE

Electrocardiographic left atrial abnormality has been associated with stroke independently of atrial fibrillation (AF), suggesting that atrial thromboembolism may occur in the absence of AF. If true, we would expect an association with cryptogenic or cardioembolic stroke rather than noncardioembolic stroke.

METHODS

We conducted a case-cohort analysis in the Northern Manhattan Study, a prospective cohort study of stroke risk factors. P-wave terminal force in lead V1 was manually measured from baseline ECGs of participants in sinus rhythm who subsequently had ischemic stroke (n=241) and a randomly selected subcohort without stroke (n=798). Weighted Cox proportional hazard models were used to examine the association between P-wave terminal force in lead V1 and stroke etiologic subtypes while adjusting for baseline demographic characteristics, history of AF, heart failure, diabetes mellitus, hypertension, tobacco use, and lipid levels.

RESULTS

Mean P-wave terminal force in lead V1 was 4452 (±3368) μV*ms among stroke cases and 3934 (±2541) μV*ms in the subcohort. P-wave terminal force in lead V1 was associated with ischemic stroke (adjusted hazard ratio per SD, 1.20; 95% confidence interval, 1.03-1.39) and the composite of cryptogenic or cardioembolic stroke (adjusted hazard ratio per SD, 1.31; 95% confidence interval, 1.08-1.58). There was no definite association with noncardioembolic stroke subtypes (adjusted hazard ratio per SD, 1.14; 95% confidence interval, 0.92-1.40). Results were similar after excluding participants with a history of AF at baseline or new AF during follow-up.

CONCLUSIONS

ECG-defined left atrial abnormality was associated with incident cryptogenic or cardioembolic stroke independently of the presence of AF, suggesting atrial thromboembolism may occur without recognized AF.

Demographic Differences in Catheter Ablation After Hospital Presentation With Symptomatic Atrial Fibrillation

BACKGROUND

Catheter ablation is increasingly used for rhythm control in symptomatic atrial fibrillation (AF), but the demographic characteristics of patients undergoing this procedure are unclear.

METHODS AND RESULTS

We used data on all admissions at nonfederal acute care hospitals in California, Florida, and New York to identify patients discharged with a primary diagnosis of AF between 2006 and 2011. Our primary outcome was readmission for catheter ablation of AF, identified using validated International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. Cox regression models were used to assess relationships between demographic characteristics and catheter ablation, adjusting for Elixhauser comorbidities. We identified 397 612 eligible patients. Of these, 16 717 (4.20%, 95% CI 0.41 to 0.43) underwent ablation. These patients were significantly younger, more often male, more often white, and more often privately insured, with higher household incomes and lower rates of medical comorbidity. In Cox regression models, the likelihood of ablation was lower in women than men (hazard ratio [HR] 0.83; 95% CI 0.80 to 0.86) despite higher rates of AF-related rehospitalization (HR 1.23; 95% CI 1.21 to 1.24). Compared to whites, the likelihood of ablation was lower in Hispanics (HR 0.60; 95% CI 0.56 to 0.64) and blacks (HR 0.68; 95% CI 0.64 to 0.73), even though blacks had only a slightly lower likelihood of AF-related rehospitalization (HR 0.97; 95% CI 0.94 to 0.99) and a higher likelihood of all-cause hospitalization (HR 1.38; 95% CI 1.37 to 1.39). Essentially the same pattern existed in Hispanics.

CONCLUSIONS

We found differences in use of catheter ablation for symptomatic AF according to sex and race despite adjustment for available data on demographic characteristics and medical comorbidities.

The association of the QT interval with atrial fibrillation and stroke: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Prolongation of the QT interval is associated with an increased risk of atrial fibrillation (AF) and stroke.

OBJECTIVES

The purpose of this analysis was to determine if AF explains the association between prolonged QT and stroke.

METHODS

A total of 6305 participants (mean age 62 ± 10 years; 54% women; 38% whites; 27% blacks; 23% Hispanics; 12% Chinese-Americans) from the Multi-Ethnic Study of Atherosclerosis (MESA) were included in this analysis. A linear scale was used to compute heart rate-adjusted QT (QT(a)). Prolonged QT(a) was defined as ≥ 460 ms in women and ≥ 450 ms in men. Incident AF cases were identified using hospital discharge records and Medicare claims data. Vascular neurologists adjudicated stroke events by medical record review. Cox regression was used to examine the association between prolonged QT(a) and stroke with and without AF.

RESULTS

A total of 216 (3.4%) of study participants had prolonged QT(a). Over a median follow-up of 8.5 years, 280 (4.4%) participants developed AF and 128 (2.0%) participants developed stroke. In a multivariable Cox regression analysis adjusted for socio-demographics, cardiovascular risk factors, and potential confounders, prolonged QT(a) was associated with an increased risk of AF (HR = 1.7, 95% CI 1.1, 2.6) and stroke (HR = 2.3, 95% CI 1.3, 4.1). When AF was included as a time-dependent covariate, the association between prolonged QT(a) and stroke was not substantively altered (HR = 2.4, 95% CI 1.3, 4.3).

CONCLUSION

The increased risk of stroke in those with prolonged QT potentially is not explained by documented AF. Further research is needed to determine if subclinical AF explains the association between the QT interval and stroke.

Electrocardiographic left atrial abnormality and stroke subtype in the atherosclerosis risk in communities study

OBJECTIVE

The aim of this study was to assess the relationship between abnormally increased P-wave terminal force in lead V1 , an electrocardiographic (ECG) marker of left atrial abnormality, and incident ischemic stroke subtypes. We hypothesized that associations would be stronger with nonlacunar stroke, given that we expected left atrial abnormality to reflect the risk of thromboembolism rather than in situ cerebral small-vessel occlusion.

METHODS

Our cohort comprised 14,542 participants 45 to 64 years of age prospectively enrolled in the Atherosclerosis Risk in Communities study and free of clinically apparent atrial fibrillation (AF) at baseline. Left atrial abnormality was defined as PTFV1 >4,000μV*ms. Outcomes were adjudicated ischemic stroke, nonlacunar (including cardioembolic) ischemic stroke, and lacunar stroke.

RESULTS

During a median follow-up period of 22 years (interquartile range, 19-23 years), 904 participants (6.2%) experienced a definite or probable ischemic stroke. A higher incidence of stroke occurred in those with baseline left atrial abnormality (incidence rate per 1,000 person-years, 6.3; 95% confidence interval [CI]: 5.4-7.4) than in those without (incidence rate per 1,000 person-years, 2.9; 95% CI: 2.7-3.1; p < 0.001). In Cox regression models adjusted for potential confounders and incident AF, left atrial abnormality was associated with incident ischemic stroke (hazard ratio [HR]: 1.33; 95% CI: 1.11-1.59). This association was limited to nonlacunar stroke (HR, 1.49; 95% CI: 1.07-2.07) as opposed to lacunar stroke (HR, 0.89; 95% CI: 0.57-1.40).

INTERPRETATION

We found an association between ECG-defined left atrial abnormality and subsequent nonlacunar ischemic stroke. Our findings suggest that an underlying atrial cardiopathy may cause left atrial thromboembolism in the absence of recognized AF.

Hospital Readmission Rates Among Mechanically Ventilated Patients With Stroke

BACKGROUND AND PURPOSE

Tracheostomy is frequently performed in patients with severe ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. Little is known about readmission rates among stroke patients who undergo mechanical ventilation.

METHODS

We used previously validated International Classification of Diseases, Ninth Edition-Clinical Modification codes and data on all discharges from nonfederal acute care hospitals in 3 states. We compared readmission rates among mechanically ventilated patients with stroke who were discharged with or without a tracheostomy.

RESULTS

Among 39,881 patients who underwent mechanical ventilation during the index stroke hospitalization and survived to discharge, 10,690 (26.8%; 95% confidence interval, 26.4%-27.2%) underwent tracheostomy. During a mean follow-up period of 3.4 (±2.0) years, the overall incidence rate of readmissions was 4.25 (95% confidence interval, 4.22-4.28) per 100 patients per 30 days. The rate of any readmissions within 30 days was 26.9% among patients with tracheostomy compared with 22.5% among those without a tracheostomy (absolute risk difference, 4.4%; 95% confidence interval, 3.5%-5.4%; P<0.001). After adjustment for potentially confounding variables, tracheostomy was associated with a slightly increased readmission rate (incidence rate ratio, 1.07; 95% confidence interval, 1.03-1.11).

CONCLUSIONS

Approximately one quarter of mechanically ventilated patients with stroke who survive to discharge are readmitted to the hospital within 30 days. Readmission rates are significantly higher in patients with stroke who undergo tracheostomy, but the difference is not clinically meaningful. Thirty-day readmission rates among mechanically ventilated patients with stroke are similar to Medicare beneficiaries hospitalized with major medical diseases such as pneumonia.

Clipping and Coiling of Unruptured Intracranial Aneurysms Among Medicare Beneficiaries, 2000 to 2010

BACKGROUND AND PURPOSE

Endovascular coiling therapy is increasingly popular for obliteration of unruptured intracranial aneurysms, but older patients face higher procedural risks and shorter periods during which an untreated aneurysm may rupture causing subarachnoid hemorrhage (SAH). We assessed trends in clipping and coiling of unruptured intracranial aneurysms, outcomes after clipping and coiling of unruptured intracranial aneurysms, and in SAH among Medicare beneficiaries.

METHODS

Using 2000 to 2010 Medicare Provider Analysis and Review data, we identified 2 cohorts of patients admitted electively for clipping or coiling of an unruptured aneurysm: (1) utilization cohort (2000-2010): patients ≥65 years enrolled ≥1 month in a given year and (2) outcomes cohort (2001-2010): patients ≥66 years of age enrolled in Medicare for ≥1 year. We calculated rates of clipping, coiling, and SAH per 100 000 Medicare beneficiaries. We tested for trends in the risk of in-hospital mortality and complications, discharge destination, 30-day mortality, 30-day readmissions, and length of hospitalization.

RESULTS

Characteristics of patients undergoing clipping (n=4357) or coiling (n=7942) did not change appreciably. Overall, 30-day mortality, in-hospital complications, and 30-day readmissions decreased, generally reaching their lowest levels in 2008 to 2010 (1.6%, 25.0%, and 14.5% for clipping and 1.5%, 13.8%, and 11.0% for coiling, respectively). Procedural treatment rates per 100 000 beneficiaries increased from 1.4 in 2000 to 6.0 in 2010, driven mainly by increased use of coiling but SAH rates did not decrease.

CONCLUSIONS

Although outcomes tended to improve over time, increased preventative treatment of unruptured intracranial aneurysms among Medicare beneficiaries did not result in a population-level decrease in SAH rates.

Temporal relationship between infective endocarditis and stroke

OBJECTIVE

Stroke frequently complicates infective endocarditis (IE). However, the temporal relationship between these diseases is uncertain.

METHODS

We performed a retrospective study of adult patients hospitalized for IE between July 1, 2007, and June 30, 2011, at nonfederal acute care hospitals in California. Previously validated diagnosis codes were used to identify the primary composite outcome of ischemic or hemorrhagic stroke during discrete 1-month periods from 6 months before to 6 months after the diagnosis of IE. The odds of stroke in these periods were compared with the odds of stroke in the corresponding 1-month period 2 years earlier, which was considered the baseline risk of stroke.

RESULTS

Among 17,926 patients with IE, 2,275 strokes occurred within the 12-month period surrounding the diagnosis of IE. The risk of stroke was highest in the month after diagnosis of IE (1,640 vs 17 strokes in the corresponding month 2 years prior). This equaled an absolute risk increase of 9.1% (95% confidence interval 8.6%-9.5%) and an odds ratio of 96.5 (95% confidence interval 60.1-166.0). Stroke risk was significantly increased beginning 4 months before the diagnosis of IE and lasting 5 months afterward. Similar temporal patterns were seen when ischemic and hemorrhagic strokes were considered separately.

CONCLUSIONS

The association between IE and stroke persists for longer than previously reported. Most diagnoses of stroke and IE are made close together in time, but a period of heightened stroke risk becomes apparent several months before the diagnosis of IE and lasts for several months afterward.

Race- and sex-related differences in care for patients newly diagnosed with atrial fibrillation

BACKGROUND

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.

OBJECTIVE

We sought to determine whether significant race and sex differences exist in the treatment of newly diagnosed AF in Medicare beneficiaries.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Cost-Effectiveness of Carotid Plaque MR Imaging as a Stroke Risk Stratification Tool in Asymptomatic Carotid Artery Stenosis

PURPOSE

To evaluate the cost-effectiveness of a decision-making rule based on the magnetic resonance (MR) imaging assessment of intraplaque hemorrhage (IPH) in patients with asymptomatic carotid artery stenosis.

MATERIALS AND METHODS

Two competing stroke prevention strategies were compared: (a) an intensive medical therapy-based management strategy versus (b) an imaging-based strategy in which the subset of patients with asymptomatic carotid artery stenosis with IPH on MR images would undergo immediate carotid endarterectomy in addition to ongoing intensive medical therapy. Patients in the medical therapy-only group could undergo carotid endarterectomy only with substantial carotid artery stenosis disease progression. Lifetime quality-adjusted life years (QALYs) and costs were modeled for patients with asymptomatic carotid artery stenosis with 70%-89% and 50%-69% carotid artery stenosis at presentation. Risks of stroke and complications from carotid endarterectomy, costs, and quality of life values were estimated from published sources.

RESULTS

The medical therapy-based strategy had a lower life expectancy (12.65 years vs 12.95 years), lower lifetime QALYs (9.96 years vs 10.05 years), and lower lifetime costs ($13 699 vs $15 297) when compared with the MR imaging IPH-based strategy. The incremental cost-effectiveness ratio (ICER) for the MR imaging IPH strategy compared with the medical therapy-based strategy was $16 000 per QALY by using a base-case 70-year-old patient. When using starting patient ages of 60 and 80 years, the ICERs for the MR imaging IPH strategy were $3100 per QALY and $73 000 per QALY, respectively. The ICERs for the MR imaging IPH strategy were slightly higher at all ages for 50%-69% stenosis but remained below a willingness-to-pay threshold of $100 000 per QALY for starting ages of 60 and 70 years.

CONCLUSION

MR imaging IPH can be used as a cost-effective tool to identify patients with asymptomatic carotid artery stenosis most likely to benefit from carotid endarterectomy.

Magnetic resonance angiography detection of abnormal carotid artery plaque in patients with cryptogenic stroke

Background

Magnetic resonance imaging of carotid plaque can aid in stroke risk stratification in patients with carotid stenosis. However, the prevalence of complicated carotid plaque in patients with cryptogenic stroke is uncertain, especially as assessed by plaque imaging techniques routinely included in acute stroke magnetic resonance imaging protocols. We assessed whether the magnetic resonance angiography–defined presence of intraplaque high-intensity signal (IHIS), a marker of intraplaque hemorrhage, is associated with ipsilateral cryptogenic stroke.

Methods and Results

Cryptogenic stroke patients with magnetic resonance imaging evidence of unilateral anterior circulation infarction and without hemodynamically significant (≥50%) stenosis of the cervical carotid artery were identified from a prospective stroke registry at a tertiary-care hospital. High-risk plaque was assessed by evaluating for IHIS on routine magnetic resonance angiography source images using a validated technique. To compare the presence of IHIS on the ipsilateral versus contralateral side within individual patients, we used McNemar’s test for correlated proportions. A total of 54 carotid arteries in 27 unique patients were included. A total of 6 patients (22.2%) had IHIS-positive nonstenosing carotid plaque ipsilateral to the side of ischemic stroke compared to 0 patients who had IHIS-positive carotid plaques contralateral to the side of stroke (P=0.01). Stroke severity measures, diagnostic evaluations, and prevalence of vascular risk factors were not different between the IHIS-positive and IHIS-negative groups.

Conclusions

Our findings suggest that a proportion of strokes classified as cryptogenic may be mechanistically related to complicated, nonhemodynamically significant cervical carotid artery plaque that can easily be detected by routine magnetic resonance imaging/magnetic resonance angiography acute stroke protocols.