Risk Factors For Thromboembolic Stroke Research Articles

Left atrial appendage occlusion in ventricular assist device patients to decrease thromboembolic events: A computer simulation study.

Atrial fibrillation (AF) is a common comorbidity in left ventricular assist device (LVAD) patients and has been identified as a risk factor for thromboembolic stroke. Blood stagnation within the left atrial appendage (LAA) is considered a possible major source of thrombosis and clinical studies have shown reduced thromboembolic risk after LAA occlusion (LAAO). Therefore, this study aims to investigate the effect of LAAO on thrombosis-related parameters using patient-specific simulations. Left ventricular and left atrial geometries of an LVAD patient were obtained from computed tomography and combined with hemodynamic data with either sinus rhythm (SR) or AF generated by a lumped parameter model. In four simulations applying contractile walls, stagnation volume and blood residence times were evaluated with or without AF and with or without LAAO. Reduced atrial contraction in AF resulted in unfavorable flow dynamics within the left atrium. The average atrial velocity was lower for the AF simulation when compared to SR, resulting in a 55% increase in the atrial stagnation volume (from 4.2 to 6.5 cm3). Moreover, blood remained in the LAA for more than 8 cardiac cycles. After LAAO the atrial stagnation decreased from 4.2 to 1.4 cm3 for SR and from 6.5 to 2.3 cm3 for the AF simulation. A significant stagnation volume was found in the LAA for both SR and AF, with larger values occurring with AF. These regions are known as potential sources for thrombus formation and can be diminished by LAAO. This significantly improved the thrombus-related flow parameters and may also lower the risk of thromboembolic events from the appendage.

Better prediction of stroke in atrial fibrillation with incorporation of cancer in CHA2DS2VASC score: CCHA2DS2VASC score.

IntroductionAtrial fibrillation (AF) is associated with an increased risk of stroke. Despite evidence linking cancer and thrombosis, cancer is not part of the CHA2DS2VASc score.HypothesisCancer is an independent risk factor for thromboembolic stroke in patients with AF.MethodThe SEER database was utilized to identify patients with lung, colon, breast, and prostate cancers with AF and no prior diagnosis of stroke and. compared to controls within the dataset. The primary endpoint was rates of stroke per 100 person-years. Cox regression modeling and a nested model comparing CHA2DS2VASc score (Model 1) with a complete model including cancer diagnosis (Model 2) were performed. Models were compared using Akaike Information Criterion (AIC) and Net Reclassification Index (NRI). A propensity-matched cohort with equivalent CHA2DS2VASc scores determining stroke-free survival was also performed.ResultsA total of 101,185 patients were included in the analysis, with 48,242 in the Cancer and 52,943 in the Non-cancer Group. Stroke rate per 100 person-years was significantly higher in the Cancer Group. The CHA2DS2VASc model (Model 1) was compared against a model including cancer (Model 2) showing improved predictability as assessed by both NRI and AIC. Cox regression analysis calculated a hazard ratio of 1.085 for Cancer, which was comparable to age >75, female sex, and diabetes. Propensity matched Kaplan-Meier curve demonstrated a decreased probability of stroke-free survival in the Cancer Group.ConclusionCancers increase the risk of stroke in patients with AF. Consideration should be given to the addition of cancer to the clinical scoring system.

Early Thromboembolic Stroke Risk of Postoperative Atrial Fibrillation Following Cardiac Surgery

The authors aimed to study the association between postoperative atrial fibrillation (POAF) and thromboembolic stroke and to determine risk factors for thromboembolic stroke after cardiac surgery. The authors performed a secondary analysis from a randomized controlled trial (GRIP-COMPASS). The patients with thromboembolic stroke were compared with those without thromboembolic stroke, and the difference in the incidence of POAF between these groups was assessed. Odds ratios (OR) were calculated using logistic regression analyses. Brain imaging was studied for the occurrence of thromboembolic stroke during hospital admission, and POAF was monitored for seven days. To assess which characteristics were associated with occurrence of thromboembolic stroke, stepwise backward regression analysis was performed. All adult consecutive cardiac surgery patients admitted postoperatively to the intensive care unit. Academic tertiary care medical center. None. Of the 910 patients included in this study, 26 patients (2.9%) had a thromboembolic stroke during hospital admission. The incidence of POAF during the first seven days after cardiac surgery in those with thromboembolic stroke was 65%, compared with 39% in those without thromboembolic stroke: adjusted OR 3.01 (95% confidence interval, 1.13-8.00). POAF, a history of peripheral vascular disease, a higher EuroSCORE, and a longer duration of surgery were associated with thromboembolic stroke. POAF within seven days after cardiac surgery was associated with a three-fold increased risk for a thromboembolic stroke during hospital admission. Expeditious treatment of POAF may, therefore, reduce early stroke risk after cardiac surgery.

P1206Some potential risk factors for thromboembolic stroke in patients with rheumatoid arthritis and paroxysmal atrial fibrillation

P1206Some potential risk factors for thromboembolic stroke in patients with rheumatoid arthritis and paroxysmal atrial fibrillation

Percutaneous Closure of the Left Atrial Appendage for Stroke Prevention in Atrial Fibrillation

Atrial fibrillation is an important risk factor for thromboembolic stroke and it significantly increases the risk of stroke. The left atrial appendage (LAA) is the most common site of thrombus formation in nonvalvular atrial fibrillation, and the recent applications of percutaneous LAA closure devices offer a promising alternative for patients who are unable to tolerate lifelong anticoagulation. Critical care nurses who understand the procedures and are familiar with the various devices used for LAA closure will be well prepared to provide optimum care and appropriate education for these patients.

Atrial fibrillation may be a hidden factor for the development of cognitive impairment in patients with heart failure.

To the editor We read the article entitled ‘Cognitive impairment in heart failure patients’ by Leto, et al. [1] with great interest. In this review, they demonstrated pathophysiological determinants of cognitive impairment in heart failure (HF) population. HF prevalence is increasing in the general population throughout the world. As HF is a complex clinical entity, underlying mechanisms with HF and cognitive impairment are mixed and intertwined. HF is a well known risk factor for dementia and functional brain abnormalities. Co-morbidities such as hypertension and diabetes are main reasons for the association between HF and cognitive impairment as well as decreased cerebral perfusion due to systolic dysfunction. Medications in HF populations also play a role in development of cognitive impairment through side effects on cerebral perfusion. [2] In the present review, the authors pointed out important variables that can be related with HF and cognitive impairment such as left ventricular ejection fraction, systolic and diastolic blood pressure, NYHA functional class and B-type natriuretic peptide. However, atrial fibrillation (AF) which is a most prevalent arrhythmia in general population has also shown to be related to cognitive decline. [3] Furthermore, due to the silent attacks, undiagnosed episodes of paroxysmal AF have been frequently encountered in this subjects. The incidence of AF was increased in the elderly patients. The prevalence of AF was found to be 9% in individuals > 80 years of age and 0.1% in subjects < 55 years of age. [4] These data are derived from the trials in which the diagnosis was based on a 12-lead electrocardiogram obtained during an office visit. According to the duration of the episodes, AF is classified into 3 types: paroxysmal AF, persistent AF, and permanent AF. While the other types of AF can be easily diagnosed with routine 12-lead ECG, paroxysmal AF may be overlooked. In order to determine attacks of paroxysmal AF, ambulatory monitoring is required. Therefore, it is presumed that the real-world prevalence of AF is higher than those determined in the trials. The cognitive impairment due to AF in elderly patients is both related with micro-emboli and a decline in cerebral perfusion. It seems that AF may exacerbate HF and subsequent cerebral blood flow reduction. Independently from its type, AF increases the risk of thromboembolism five times. [4] CHADS-VASc scoring system has been using in patients with AF in order to quantify the risk for thromboembolism. According to this scoring system, existence of congestive heart failure, hypertension, age 65 to 74 years, age ≥ 75 years (doubled risk), diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism (doubled risk), vascular disease and female gender are risk factors for thromboembolic stroke in patients with AF. [5] It has been particularly indicated in this scoring system that the embolic risk of the elderly people with AF is as high as the patients with prior stroke. With the aging population in our modern world, it is obvious to be an incremental rise in the prevalence of AF. Furthermore, it is important to shed light on the relationship between cognitive impairment and AF as a main problem in patients with HF, so that preventative efforts will lead way to reduce the burden of cognitive impairment in HF patients. Therefore, in a review addressing cognitive impairment in HF population, we believe that discussing AF might be useful for researchers dealing with this group of patients.

Abstract 044: Transient Receptor Potential Channel 6 (TRPC6) Is An Important Mediator Of Mechanical Stretch Responses In The Atrial Endocardial Endothelium.

Atrial fibrillation (AF) is the most common heart arrhythmia and a major risk factor for thromboembolic stroke and hearth failure. Atrial pressure and/or volume overload that cause increased mechanical stretch in the atrium are the common features of the diseases that cause AF. The latter suggests that mechanical stress has a major role in the pathogenesis of AF. The atrial endocardial endothelium (AE) is the interface between the myocardium and the circulating blood but its role in the mechanotransduction in the atrium is unknown. Endothelial cells (EC) are very sensitive and responsive to external mechanical stimuli and AE dysfunction has been reported in individuals with AF. We therefore hypothesized that the AE is an important mediator of stretch responses in the atrium and that stretch-induced AE dysfunction may be critical for initiation and/or maintenance of AF. We investigated the AE responses to increased mechanical stress by subjecting novel primary AE cells to mechanical stretch. The mechanical stretch conditions included cyclic stretch of 30 cycles/min at 10 percent displacement. The AE cells were stretched for 1-10 min, and 1, 4, 8, and 24h. Changes in the cell shape with elongation, hypertrophy and re-alignment of the cells and their stress fibres in a direction perpendicular to the lines of stretch were first observed after 1h of stretch. TRPC6 is a stretch sensitive ion channel and important regulator of Ca2+-signalling in the EC cells. Immunostaining and Western blot analysis showed redistribution and changed levels of expression of TRPC6 in the stretched AE cells, respectively. The latter suggested changed TRPC6 activity which was evaluated by measuring extracellular Ca2+ influx through the TRPC6 channels in the AE cells under baseline and stretch conditions. We found that short-stretch (1-10min) increased TRPC6 activity, while the long stretch (1-24h) silenced it. Based on these findings it could be concluded that TRPC6 is an important mediator of the mechanical stretch responses in the AE; the functional consequences of the altered channel activity are predetermined by the duration of the stretch-stimulus; and TRPC6 changes in the stretched AE may cause AE dysfunction through altered Ca2+ signalling that contributes to AF development.

Stroke and Death Prediction with the Impact of Vascular Disease in Patients with Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia encountered in the U.S. and the growing burden of AF has profound health implications due to the association of AF with an increased risk of stroke, heart failure, and mortality. AF is a significant risk factor for thromboembolic stroke; and also independently increases total mortality in patients with and without cardiovascular disease. Various risk stratification schemes such as CHADS2 and CHA2DS2-VASc have been implemented in clinical practice to determine the risk of cardio-embolic stroke, and need for thrombo-prophylaxis in patients with AF. AF is also closely related to the pathophysiology of other cardiovascular and peripheral vascular disease. Many patients with AF have associated atherosclerosis given that many risk factors for atherosclerosis also predispose to AF. Myocardial infarction (MI) is also closely related to AF and its clinical course is affected by new onset AF. This review elucidates the impact of AF on major adverse cardiovascular events and mortality outcomes in relation to stroke, coronary artery disease and peripheral vascular disease.

Stroke Prevention in Atrial Fibrillation – The Unmet Need and Morbidity Burden

Atrial fibrillation (AF) occurs in epidemic proportion and is now recognised to occur in about 2 % of the general population. Its prevalence is age-related – about 10 % of 80-year-olds have this arrhythmia with hypertension, valvular disease and heart failure being the most frequent underlying conditions. Up to 10 % of cases of AF may be idiopathic, although genetic, autonomic, inflammatory, infective and toxic causes may account for many of these. AF is associated with serious consequences of which death, sudden death, stroke, heart failure, pulmonary disease and hospitalisation are the most serious. Thromboembolic stroke occurs in about 5 % of AF patients each year, which is approximately five-fold the stroke rate in age and gender-matched patients without AF. AF-related thromboembolic stroke accounts for 15–20 % of all strokes. Risk factors for thromboembolic stroke include clinical factors (such as age, female gender, diabetes, heart failure, hypertension, renal failure and arterial disease), elevated levels of biomarkers (such as troponin, B-type natriuretic peptide, C-reactive protein and micro-albuminuria) and echocardiographic features (such as left ventricular systolic dysfunction, increased left atrial size, left atrial ‘smoke’ and thrombus). There are several clinical risk stratification schemes used to identify AF patients at high risk of thromboembolic stroke. The CHADS2 scheme is popular, but tends to group a high proportion of patients in low and intermediate risk categories. The recently introduced CHA2DS2-VASc scheme identifies truly low-risk patients and avoids placing more than a small proportion in a low or intermediate risk category where there is a guideline mandated choice between anticoagulant, antiplatelet or no therapy. This scheme, which is well validated, has been recommended by the European Society of Cardiology in anticipation of the introduction of new and safer oral anticoagulants. Although warfarin is an effective therapy for the prevention of thromboembolic complications of AF it is inadequately used because of fear of haemorrhagic complications and the difficulties associated with monitoring and maintenance of the correct level of anticoagulation. At present, as few as 20 % of patients who should be anticoagulated are effectively treated. New anticoagulant therapies, which are much easier to use, coupled with more attention to the indications for anticoagulation, should result in more effective anticoagulation and a major reduction in the thromboembolic complications associated with AF.

The Factor V Leiden, Prothrombin Gene 20210GA, Methylenetetrahydrofolate Reductase 677CT and Platelet Glycoprotein IIIa 1565TC Mutations in Patients With Acute Ischemic Stroke and Atrial Fibrillation

We wanted to investigate whether common prothrombotic mutations are more prevalent in patients with atrial fibrillation who have had a stroke than in healthy controls. We also wanted to assess whether early recurrent ischemic cerebrovascular events were more frequent among carriers of the factor V Leiden or the prothrombin gene mutations than among others. We used a case-control design with 367 patients with acute ischemic stroke and atrial fibrillation (cases) and 482 healthy blood donors (controls). All mutations were detected with conventional polymerase-chain reaction protocols. The odds ratios for carriers of the factor V Leiden, prothrombin gene 20210GA, methylenetetrahydrofolate reductase 677CT, or platelet glycoprotein IIIa 1565TC (Pl(A2)) mutation were 0.91, (95% CI, 0.51 to 1.59), 2.25 (95% CI, 0.61 to 8.90), 0.83 (0.61 to 1.13), and 0.79 (0.57 to 1.10), respectively. Early recurrent ischemic stroke and total recurrent ischemic cerebrovascular events were slightly more frequent among carriers of the factor V Leiden mutation than among noncarriers: odds ratio 1.45 (95% CI, 0.41 to 5.1), and 1.59 (0.61 to 4.1), respectively. None of the patients with recurrent ischemic cerebrovascular events had the prothrombin gene mutation. These mutations are not important risk factors for thromboembolic stroke associated with atrial fibrillation. Carriers of the factor V Leiden mutation had a small, nonsignificantly higher risk of early recurrent ischemic cerebrovascular events.

Gender-specific risk factors for thromboembolic stroke with acute myocardial infarction

Gender-specific risk factors for thromboembolic stroke with acute myocardial infarction

Prevention of stroke in chronic and recurrent atrial fibrillation: role of the emergency department in identification of "at-risk" patients.

The objective was to determine the proportion of patients presenting to the Emergency Department (ED) in atrial fibrillation (AF) who are at high risk of thromboembolic stroke as defined by the American Heart Association and who might benefit from anticoagulation therapy. We enrolled all patients identified as having AF between 28th June 1999 and 26th March 2000. Data collected included demographic information, presenting complaint, discharge diagnosis, risk factors for thromboembolic stroke, contraindications to anticoagulation (as defined by the Stroke Prevention in AF Investigators), admission and discharge medications, and cardiac rhythm on presentation and at discharge. 193 patients were identified within the study period. Two patient histories were not available for review. 121 patients had a prior history of AF. Of these, 65 patients were at high risk for thromboembolic stroke and had no contraindication to anticoagulation therapy 43 (66%) were on Warfarin at presentation but 14 (22%) were on Aspirin and 8 (12%) were on neither. 34% of patients with chronic atrial fibrillation presenting to the ED, at high risk of thromboembolic stroke and without contra-indication to anticoagulation, were not anticoagulated on presentation. ED attendance provides an opportunity for intervention for the prevention of stroke in this group.

Atrial fibrillation and anticoagulation in patients with permanent pacemakers: implications for stroke prevention.

Several large prospective randomized trials have demonstrated that anticoagulation with warfarin reduces the risk of thromboembolic stroke in high risk patients with chronic AF by approximately 70%. Large numbers of patients with permanent pacemakers have AF, and anticoagulation rates in this population have not been described. In a prospective analysis of 110 consecutive patients attending the pacemaker clinic of a large university hospital we assessed the number of patients with AF and the proportion of these patients who were receiving anticoagulation to prevent thromboembolic stroke. Where necessary, temporary pacemaker reprogramming to low ventricular rates was utilized to facilitate the diagnosis of AF. Fifty-three of the 110 patients (48%) were diagnosed with AF, all of whom (100%) had accepted high risk factors for thromboembolic stroke. Only eight of the 53 (15%) had been anticoagulated with warfarin. Thirty-six of the 53 patients (68%) diagnosed with AF had no prior documented diagnosis of chronic AF, and the majority had no symptoms suggesting AF. A single lead II ECG was insufficient in 67 of the 110 patients (61%) to diagnose the underlying atrial rhythm; the remainder required 12-lead ECGs or temporary pacemaker reprogramming to low ventricular rates to diagnose the underlying atrial rhythm. AF is common in patients with permanent pacemakers. It is commonly asymptomatic, and anticoagulation is markedly underutilized in reducing stroke risk in these patients. Attention to the possibility of AF in paced patients should allow prompt diagnosis and allow both the initiation of anticoagulation in order to reduce thromboembolic stroke risk and consideration for cardioversion of AF to sinus rhythm.

Elevated serum cholesterol is a risk factor for both coronary heart disease and thromboembolic stroke in Hawaiian Japanese men. Implications of shared risk.

The relation between total serum cholesterol level and thromboembolic or nonhemorrhagic stroke is controversial. The Honolulu Heart Program cohort of Japanese-American men provides data which show that elevated serum cholesterol is an independent predictor of thromboembolic stroke as well as coronary heart disease (CHD). The data are presented to suggest that the association of elevated cholesterol with stroke is sometimes underestimated or underreported partly because of competing or shared risk with CHD, the other major atherosclerotic end point. The data are based on 6352 men (aged 51 to 74 years) at baseline examination (1971 to 1974) who were free of clinical CHD and stroke and were followed an average of 15 years for new cases of both end points. Relative risks of serum cholesterol for CHD and thromboembolic stroke were calculated, controlling for other major cardiovascular covariates. There was a continuous and progressive increase in both CHD and thromboembolic stroke rates with increasing levels of serum cholesterol. The relative risk between the highest and lowest quartiles of serum cholesterol was 1.7 (95% confidence interval, 1.4 to 2.0) for CHD and 1.4 (95% confidence interval, 1.1 to 1.9) for thromboembolic stroke. There was a decline in the difference in relative risks between CHD and thromboembolic stroke in older men (aged 60 years and older) compared with younger men (aged younger than 60 years). These data provide additional evidence that elevated serum cholesterol should be considered a primary risk factor for thromboembolic stroke, presumably through its effect on both coronary and cerebrovascular atherosclerosis. It is suggested that this association is sometimes underestimated or underreported partly because of shared or competing risk with CHD, the clinical manifestation of atherosclerosis that generally occurs earlier in life and with greater frequency than thromboembolic stroke.

Risk factors for thromboembolic stroke in elderly patients with chronic atrial fibrillation

Chronic atrial fibrillation (AF) in the presence or absence of rheumatic valvular heart disease is associated with an increased incidence of stroke. 1,2 We reported in a prospective study that at 27-month follow-up, echocardiographic left ventricular (LV) hypertrophy in elderly patients with systolic or diastolic hypertension was associated with an increased incidence of new atherothrombotic brain infarction. 3 We also demonstrated in a prospective study that at 3-year follow-up, risk factors for atherothrombotic brain infarction were cigarette smoking, systolic or diastolic hypertension and diabetes mellitus in elderly men and systolic or diastolic hypertension, diabetes mellitus and obesity in elderly women. 4 This report correlates in elderly patients with chronic AF the prevalence of thromboembolic (TE) stroke with the presence or absence of rheumatic mitral stenosis, mitral anular calcium, valvular aortic stenosis, systolic or diastolic hypertension, prior myocardial infarction, left atrial enlargement and LV hypertrophy.

The association between migraine and cerebral vascular events: An analytical review

This paper explores the uncertain relationship between migraine headache and thromboembolic stroke. In reviewing the literature that links migraine with thromboembolic cerebral vascular events, a distinction is made between two stroke events that occur in migraine patients: stroke associated with a migraine attack (a migrainous stroke) and stroke unrelated to a migraine attack (a nondashmigrainous stroke). In a recent community-based stroke register, migrainous strokes occurred at a rate of 3.4 per 100,000 per annum. Prevalence rates for migraine in young stroke populations (11–28%) are similar to those in the general population and do not support an additional long-term risk of nondashmigrainous stroke in migraine patients. The only study providing a controlled estimate of long-term thromboembolic stroke risk (odds ratio = 1.7; 95% CI 1.3, 2.2) included only women and has not been independently confirmed. The contribution of migraine to other known risk factors for thromboembolic stroke needs to be examined further by controlled studies.

Dietary and other risk factors for stroke in Hawaiian Japanese men.

As part of an on-going longitudinal study, 7895 men of Japanese ancestry living on the island of Oahu, aged 45-68 and free of evidence of prior stroke at entry examination, have been followed by re-examinations and surveillance. During ten years of follow-up 154 men developed thromboembolic stroke, 65 developed intracranial hemorrhage, and 19 developed stroke of unknown type. There were 79 deaths attributed to stroke. The independent risk factors for thrombo-embolic stroke were elevated blood pressure, glucose intolerance, age, electrocardiographic evidence of left ventricular hypertrophy or strain, cigarette smoking and proteinuria. Attributes associated with increased risk of intracranial hemorrhage were age, elevated blood pressure, cigarette smoking, serum uric acid and, inversely, serum cholesterol level. Electrocardiographic evidence of left ventricular hypertrophy or strain significantly increased the risk of cerebral hemorrhage, but was not associated with subarachnoid hemorrhage. In univariate analysis, there was an inverse relation between dietary fat intake and thrombo-embolic and total stroke incidence. An inverse relation was also shown between protein intake and total stroke incidence. These dietary relations became statistically not significant in multivariate analysis. No relation was found between salt intake and the incidence of stroke.

Factors related to stroke incidence in Hawaii Japanese men. The Honolulu Heart Study.

As part of an ongoing longitudinal study of coronary heart disease and stroke among Japanese men in Hawaii, 8,006 men of Japanese ancestry living on the island of Oahu and aged 45-68 at entry examination have been followed by reexamination and surveillance. One hundred and eleven were found to have evidence of prior stroke at the time of the initial examination. During a six-year follow up period of the remaining 7,895 men, 94 developed definite thromboembolic stroke, 33 definite intracranial hemorrhage, and 6 developed stroke of unknown type. The principal risk factors for thromboembolic stroke were: elevated blood pressure, glucose intolerance, age, and electrocardiography evidence of left ventricular hypertrophy or strain. Attributes associated with increased risk of intracranial hemorrhage were elevated blood pressure, electrocardiographic evidence of left ventricular hypertrophy or strain, and alcohol intake. Serum cholesterol level was negatively associated with risk of intracranial hemorrhage.