Wiebers, David O.

We describe four patients with episodic bilateral vision impairment related exclusively to light exposure. Each had angiographically documented bilateral high-grade stenosis or occlusion of the internal carotid arteries. This phenomenon appears to be related to bilateral simultaneous retinal ischemia delaying regeneration of visual pigments in the pigment epithelial layer. It must be distinguished from bilateral occipital lobe ischemia caused by vertebrobasilar system disease.

Background and Purpose —There is scant population-based information on incidence and risk factors for ischemic stroke subtypes. Methods —We identified all 454 residents of Rochester, Minn, with a first ischemic stroke between 1985 and 1989 from the Rochester Epidemiology Project medical records linkage system. We used Stroke Data Bank criteria to assign infarct subtypes after reviewing medical records and brain imaging. We adjusted average annual incidence rates by age and sex to the US 1990 population and compared the age-adjusted frequency of stroke risk factors across ischemic stroke subtypes. Results —Age- and sex-adjusted incidence rates (per 100 000 population) were as follows: large-vessel cervical or intracranial atherosclerosis with >50% stenosis, 27; cardioembolic, 40; lacuna, 25; uncertain cause, 52; other or uncommon cause, 4. Sex differences in incidence rates were detected only for atherosclerosis with stenosis (47 [95% CI, 34 to 61] for men; 12 [95% CI, 7 to 17] for women). There was no difference in prior transient ischemic attack and hypertension among subtypes, and diabetes was not more common among patients with lacunar infarction than other common subtypes. Conclusions —The age-adjusted incidence rate of stroke due to stenosis of the large cervicocephalic vessels is nearly 4 times higher for men than for women. There is no association between preceding transient ischemic attack and stroke mechanism. Diabetes and hypertension are not more common among patients with lacunae. Age- and sex-adjusted incidence rates for ischemic stroke subtypes in this population can be compared with similarly determined rates from other populations.

Background— There are few published data on the incidence of fatal and nonfatal stroke in American Indians. The aims of this observational study were to determine the incidence of stroke and to elucidate stroke risk factors among American Indians. Methods and Results— This report is based on 4549 participants aged 45 to 74 years at enrollment in the Strong Heart Study, the largest longitudinal, population-based study of cardiovascular disease and its risk factors in a diverse group of American Indians. At baseline examination in 1989 to 1992, 42 participants (age- and sex-adjusted prevalence proportion 1132/100 000, adjusted to the age and sex distribution of the US adult population in 1990) had prevalent stroke. Through December 2004, 306 (6.8%) of 4507 participants without prior stroke suffered a first stroke at a mean age of 66.5 years. The age- and sex-adjusted incidence was 679/100 000 person-years. Nonhemorrhagic cerebral infarction occurred in 86% of participants with incident strokes; 14% had hemorrhagic stroke. The overall age-adjusted 30-day case-fatality rate from first stroke was 18%, with a 1-year case-fatality rate of 32%. Age, diastolic blood pressure, fasting glucose, hemoglobin A 1c, smoking, albuminuria, hypertension, prehypertension, and diabetes mellitus were risk factors for incident stroke. Conclusions— Compared with US white and black populations, American Indians have a higher incidence of stroke. The case-fatality rate for first stroke is also higher in American Indians than in the US white or black population in the same age range. Our findings suggest that blood pressure and glucose control and smoking avoidance may be important avenues for stroke prevention in this population.

Background and Purpose— Mitral annular calcification (MAC) and aortic valve (AV) sclerosis have each been linked to cardiovascular disease. Whether MAC and AV sclerosis are risk factors for stroke independent of other echocardiographic or laboratory predictors has not been established. We evaluated the relationship between MAC, AV sclerosis, and first stroke events in a population-based cohort. Methods— Our study cohort consisted of 2723 American Indians participating in the Strong Heart Study who were free of prevalent cardiovascular disease. Participants underwent standardized clinical, echocardiographic, and laboratory evaluation, and incident stroke was ascertained using validated methods. Results— During a median follow-up of 7 years, 86 strokes occurred. Age- and sex-adjusted incidence rates of stroke were significantly increased for MAC (rate ratio [RR], 3.12; 95% CI, 1.77 to 5.25) but not for AV sclerosis (RR, 1.15; 95% CI, 0.45 to 2.49). MAC was also associated with a reduced time to first stroke events after adjustment for clinical variables and the inflammatory markers C-reactive protein and fibrinogen (hazard ratio [HR], 2.42; 95% CI, 1.39 to 4.21) or the echocardiographic covariates left ventricular hypertrophy and left atrial enlargement (HR, 1.89; 95% CI, 1.04 to 3.41). Individuals with and without AV sclerosis showed no significant difference in stroke-free survival in unadjusted analyses ( P =0.698). Crossing of the survival curves precluded multivariable analysis using Cox models. Conclusions— In this cohort of American Indians without clinical cardiovascular disease, the presence of MAC, but not AV sclerosis, proved to be a strong risk factor for incident stroke after extensive adjustment for other predictors. Individuals exhibiting MAC may benefit from aggressive risk factor modification, but this will require further investigation.

Abstract OBJECTIVE To report presenting clinical symptoms, previous medical history, and survival rates for people with saccular intracranial aneurysms (IAs), in a defined population. METHODS The medical records of all residents of Olmsted County, Minnesota, with possible IAs were reviewed. Clinical manifestations at the time of diagnosis, previous medical history, demographic factors, and survival rates after diagnosis were determined. RESULTS Of 270 people with IAs detected between 1965 and 1995, 188 exhibited symptoms at the time of diagnosis, including 74% of women and 63% of men (P = 0.054). Intracranial hemorrhage (ICH) was the most common presenting symptom (60% of all patients and 86% of patients who exhibited symptoms), followed by cranial nerve palsy, transient ischemic attacks, and seizures. Survival rates after detection (with the exclusion of cases that were first detected during autopsies) were dependent on the occurrence of ICH; 23% of patients who presented with ICH died by 1 day after diagnosis, compared with 5% of those who did not exhibit symptoms or exhibited symptoms but without ICH at presentation. At 5 years, 44.7% of patients with hemorrhage had died, compared with 29.4% of patients with symptoms other than hemorrhage. After the first 24 hours after detection, survival rates did not differ significantly for those presenting with or without hemorrhage. Predictors of better survival rates also included lower age and later calendar year of presentation. CONCLUSION This study provides the first data on aneurysm characteristics, clinical symptoms, and survival rates among people with IAs in a defined population. During the study period, most aneurysms were detected in the context of an aneurysm-related symptom (particularly among women), with a large proportion of patients presenting with ICH. After the acute phase of hemorrhage, long-term survival rates among people with IAs were similar for those presenting with or without ICH.