Cardioembolic stroke: an update

Cardiovascular MRI: A valuable tool to detect cardiac source of emboli in cryptogenic ischemic strokes

OBJECTIVES

Despite a thorough work-up including transesophageal echocardiography, 20%-30% of stroke etiology remains cryptogenic. Transesophageal echocardiogram is considered the gold standard procedure to detect cardiac or aortic sources of emboli. In the recent years, cardiovascular MRI has emerged as a noninvasive, sound, and reliable modality to image morphological and functional abnormalities. In this study, we compared none contrast cardiovascular MRI to transesophageal echocardiogram, in the ability to detect cardiovascular source of embolus in cryptogenic ischemic strokes.

METHODS

A series of 24 patients who were labeled, after a thorough stroke work-up, as having cryptogenic stroke, were examined with both transesophageal echocardiogram and noncontrast cardiovascular MRI to assess for cardiac or aortic source of emboli. The cardiologist who interpreted the transesophageal echocardiograms was blinded to the results of cardiovascular MRI. At the same time, the radiologist who interpreted the cardiovascular MRI was also blinded to the results of transesophageal echocardiogram. The cardiac lesions, with potential source of emboli that were assessed in our study included left ventricular thrombus, atrial septal aneurysm, and aortic atherosclerotic disease. The ability of cardiovascular MRI to identify potential source of cardiac embolus was then compared to that of transesophageal echocardiogram.

RESULTS

Transesophageal echocardiogram detected ascending or arch aortic atherosclerotic plaque in 14 of the 24 patients. Other abnormalities detected include two atrial septal aneurysms and two left ventricular thrombus. Cardiovascular MRI was able to identify aortic atheroma in 13 patients; as well as three atrial septal aneurysms and two left ventricular thrombus. The accuracy of cardiovascular MRI to detect aortic atheroma, atrial septal aneurysm or left ventricular thrombus was great; 96%, 95.83%, and 100%, respectively.

CONCLUSION

This small study suggests that, in patients with cryptogenic stroke, cardiovascular MRI is comparable to transesophageal echocardiogram in detecting cardiac and aortic source of emboli.

Embolus Analog Trajectory Paths Under Physiological Flowrates Through Patient-Specific Aortic Arch Models

Atrial fibrillation (AF) is the most common irregular heartbeat among the world's population and is a major contributor to cardiogenic embolisms and acute ischemic stroke (AIS). However, the role AF flow plays in the trajectory paths of cardiogenic emboli has not been experimentally investigated. A physiological simulation system was designed to analyze the trajectory patterns of bovine embolus analogs (EAs) (n = 720) through four patient-specific models, under three flow conditions: steady flow, normal pulsatile flow, and AF pulsatile flow. It was seen that EA trajectory paths were proportional to the percentage flowrate split of 25–31% along the branching vessels. Overall, AF flow conditions increased trajectories through the left- (LCCA) and right (RCCA)-common carotid artery by 25% with respect to normal pulsatile flow. There was no statistical difference in the distribution of clot trajectories when the clot was released from the right, left, or anterior positions. Significantly, more EAs traveled through the brachiocephalic trunk (BCT) than through the LCCA or the left subclavian. Yet of the EAs that traveled through the common carotid arteries, there was a greater affiliation toward the LCCA compared to the RCCA (p < 0.05).

Nonatherosclerotic Pathology of the Neck Vessels: Prevalence and Flow Patterns

Objectives: To determine the prevalence and flow characteristics of nonatherosclerotic pathologies of the cervical vessels.

Design: From 1997 to 2003, 11 480 ultrasound tests were performed for neck vessel evaluation on patients with cerebrovascular symptoms and trauma, and on asymptomatic patients with a bruit, cervical mass, or prior to aortocoronary bypass. When necessary, these findings were confirmed by other imaging modalities.

Results: A total of 3010 repeated tests were excluded, leaving 8470 patients. The prevalence of nonatherosclerotic pathologies (n = 55) was 0.65%. The most common was thromboembolism (n = 19, 0.22%), followed by dissection (n = 16, 0.19%), carotid body tumors (n = 5, 0.06%), aneurysms (n = 4, 0.05%), fibromuscular dysplasia (n = 4, 0.05%), Takayasu's arteritis (n = 1, 0.01%), pseudoaneurysms (n = 5, 0.06%), and arteriovenous fistulae (n = 1, 0.01%). Cerebrovascular symptoms were present in 27 patients (49%).

Conclusion: Nonatherosclerotic pathology accounts for 0.65% of patients referred for neck vessel evaluation. About half of them are symptomatic. Diagnosis of these pathologies and knowledge of their flow characteristics is important for patient management.

Severe Orthostatic Hypotension due to Unilateral Carotid Artery Dissection

A 46-year-old woman was admitted to our hospital with mild right-sided hemiparesis and orthostatic hypotension. Magnetic resonance angiography of the neck showed stenosis of the left distal carotid sinus surrounded by intraluminal hyperintensities on both T1-weighted and T2-weighted images, representing a periluminal hematoma secondary to carotid artery dissection. The dissection hyper-extended the carotid artery wall and stimulated baroreceptors in the carotid sinus. The stimulated baroreceptors induced carotid sinus hypersensitivity, which may have been related to her orthostatic hypotension. Post-stroke orthostatic hypotension should prompt consideration of carotid artery dissection.

Silent cerebral infarcts associated with cardiac disease and procedures

The occurrence of clinically silent cerebral infarcts (SCIs) in individuals affected by cardiac disease and after invasive cardiac procedures is frequently reported. Indeed, atrial fibrillation, left ventricular thrombus formation, cardiomyopathy, and patent foramen ovale have all been associated with SCIs. Furthermore, postprocedural SCIs have been observed after left cardiac catheterization, transcatheter aortic valve implantation, CABG surgery, pulmonary vein isolation, and closure of patent foramen ovale. Such SCIs are often described as precursors to symptomatic stroke and are associated with cognitive decline, dementia, and depression. Increased recognition of SCIs might advance our understanding of their relationship with heart disease and invasive cardiac procedures, facilitate further improvement of therapies or techniques aimed at preventing their occurrence and, therefore, decrease the risk of adverse neurological outcomes. In this Review, we provide an overview of the occurrence and clinical significance of, and the available diagnostic modalities for, SCIs related to cardiac disease and associated invasive cardiac procedures.

Excessive Supraventricular Ectopic Activity and Increased Risk of Atrial Fibrillation and Stroke

Background— Prediction of stroke and atrial fibrillation in healthy individuals is challenging. We examined whether excessive supraventricular ectopic activity (ESVEA) correlates with risk of stroke, death, and atrial fibrillation in subjects without previous stroke or heart disease.

Methods and Results— The population-based cohort of the Copenhagen Holter Study, consisting of 678 healthy men and women aged between 55 and 75 years with no history of cardiovascular disease, atrial fibrillation, or stroke, was evaluated. All had fasting laboratory tests and 48-hour ambulatory ECG monitoring. ESVEA was defined as ≥30 supraventricular ectopic complexes (SVEC) per hour or as any episodes with runs of ≥20 SVEC. The primary end point was stroke or death, and the secondary end points were total mortality, stroke, and admissions for atrial fibrillation. Median follow-up was 6.3 years. Seventy subjects had SVEC ≥30/h, and 42 had runs of SVEC with a length of ≥20 SVEC. Together, 99 subjects (14.6%) had ESVEA. The risk of primary end point (death or stroke) was significantly higher in subjects with ESVEA compared with those without ESVEA after adjustment for conventional risk factors (hazard ratio=1.64; 95% confidence interval, 1.03 to 2.60; P =0.036). ESVEA was also associated with admissions for atrial fibrillation (hazard ratio=2.78; 95% confidence interval, 1.08 to 6.99; P =0.033) and stroke (hazard ratio=2.79; 95% confidence interval, 1.23 to 6.30; P =0.014). SVEC, as a continuous variable, was also associated with both the primary end point of stroke or death and admissions for atrial fibrillation.

Conclusions— ESVEA in apparently healthy subjects is associated with development of atrial fibrillation and is associated with a poor prognosis in term of death or stroke.

Discharge medications among ischemic stroke survivors

BACKGROUND

The aim of this study was to analyze the types and cost of medications prescribed at discharge for ischemic stroke survivors.

METHODS

This is a descriptive study of medications prescribed for ischemic stroke survivors admitted to Al-watani hospital during a 6-month period.

RESULTS

A total of 95 consecutive stroke patients were included in the study period; 78 (82.1%) survivors were having ischemic stroke subtype and were designated the study group. The average age of the survivors was 66.9 +/- 12.7 years. Survivors had prevalent risk factors such as diabetes mellitus (70%), hypertension (68%), and ischemic heart disease (34.6%). On average, survivors experienced a minimum of 0.73 complications (range 0-3) with the most common being infections (n = 35, 44.8%). Forty-two per cent of the ischemic stroke survivors were taking antiplatelet drugs prior to the current attack. At discharge, ischemic stroke survivors were prescribed an average of 4.9 medications from 4.3 different drug classes. All ischemic stroke survivors were prescribed antiplatelet therapy at discharge. Aspirin monotherapy was prescribed for 61 survivors while the combination of aspirin/clopidogrel antiplatelet therapy was prescribed for 17 survivors. The average monthly cost for prophylactic therapy and for medications used to treat post-stroke complication was approximately 52 USD per survivor.

CONCLUSION

Most of the patients in the study group were having the traditional risk factors for ischemic stroke and were suffering form typical post-stroke complications. Lack of medical insurance will impose a heavy financial burden on stroke survivors in Palestine.

An unusual cause of stroke from a left atrial mass

A 59-year-old woman was admitted to the hospital after having severe headache for 1 day. Her medical history was significant for coronary artery disease, diabetes, atrial fibrillation, and rheumatic heart disease. The patient was in remission from stage II left breast cancer (T2 N0 M0) in 1997, treated with lumpectomy, 6 cycles of chemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil), and local radiation therapy (total 6000 cGy). Head magnetic resonance imaging scan showed left occipital hemorrhage. Subsequent angiogram showed a possible mycotic aneurysm of distal parietal occipital branch of the posterior cerebral artery. Cardiology was consulted to evaluate for a cardioembolic source.

Stroke: epidemiology, classification, risk factors, complications, diagnosis, prevention, and medical and dental management

Cerebrovascular accident, or stroke, refers to an acute onset of neurologic deficits lasting more than 24 hours or culminating in death caused by a sudden impairment of cerebral circulation. Stroke is the third leading cause of death and a major cause of long-term disability in the United States. This article provides the dental community with an up-to-date understanding of the epidemiology, classification, risk factors, complications, diagnosis, prevention, and medical and dental management issues pertaining to stroke.

Update on stroke prevention

It is now well recognized that stroke-prone individual scan be identified in the majority of instances and that effective preventive therapy is available. Cumulative risk factors enhance the potential for stroke.The challenge is to effectively intervene to substantially reduce stroke risk.