Vascular Retinal, Neuroimaging and Ultrasonographic Markers of Lacunar Infarcts

Intima-media thickness (IMT) is increasingly used as a surrogate end point of vascular outcomes in clinical trials aimed at determining the success of interventions that lower risk factors for atherosclerosis and associated diseases (stroke, myocardial infarction and peripheral artery diseases). The necessity to promote further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT and to standardize IMT measurements is expressed through this updated consensus. Plaque is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. Standard use of IMT measurements is based on physics, technical and disease-related principles as well as agreements on how to perform, interpret and document study results. Harmonization of carotid image acquisition and analysis is needed for the comparison of the IMT results obtained from epidemiological and interventional studies around the world. The consensus concludes that there is no need to ‘treat IMT values’ nor to monitor IMT values in individual patients apart from exceptions named, which emphasize that inside randomized clinical trials should be performed. Although IMT has been suggested to represent an important risk marker, according to the current evidence it does not fulfill the characteristics of an accepted risk factor. Standardized methods recommended in this consensus statement will foster homogenous data collection and analysis. This will help to improve the power of randomized clinical trials incorporating IMT measurements and to facilitate the merging of large databases for meta-analyses.

There is scant population-based information on incidence and risk factors for ischemic stroke subtypes. 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. 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. 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.

White matter lesions (WMLs) detected on cerebral imaging scans have been hypothesized to have a microvascular etiology and to precede the development of clinical stroke. However, few clinical data are available to support these hypotheses. To examine the relationship of WMLs, retinal microvascular abnormalities, and incident clinical stroke in healthy, middle-aged men and women. The Atherosclerosis Risk in Communities Study (ARIC), a prospective, population-based cohort study conducted in 4 US communities and initiated in 1987-1989. A total of 1684 persons aged 51 to 72 years who had cerebral magnetic resonance imaging (MRI) and retinal photography at the third examination (1993-1995). Odds of WMLs, defined by standardized methods from MRI, by presence or absence of specific retinal microvascular abnormality (eg, microaneurysm, retinal hemorrhage) on retinal photograph; incident clinical stroke, ascertained after a median follow-up of 4.7 years, according to presence or absence of WMLs and retinopathy. Persons with retinopathy were more likely to have WMLs than those without retinopathy (22.9% vs 9.9%; odds ratio, 2.5; 95% confidence interval [CI], 1.5-4.0, adjusted for age, sex, race, and vascular risk factors). The 5-year cumulative incidence of clinical stroke was higher in persons with vs without WMLs (6.8% vs 1.4%; adjusted relative risk [RR], 3.4; 95% CI, 1.5-7.7) and in persons with vs without retinopathy (8.0% vs 1.4%; adjusted RR, 4.9; 95% CI, 2.0-11.9). Persons with both WMLs and retinopathy had a significantly higher 5-year cumulative incidence of stroke than those without either WMLs or retinopathy (20.0% vs 1.4%; adjusted RR, 18.1; 95% CI, 5.9-55.4). In this cohort, middle-aged persons with cerebral WMLs detected on MRI were more likely to have retinal microvascular abnormalities and to have an increased risk of clinical stroke than people without WMLs. The risk of stroke was higher when retinopathy was simultaneously present in persons with WMLs.