Susac syndrome: clinical characteristics and treatment in 29 new cases

BACKGROUND AND PURPOSE

  There are few clinical studies on the attempted treatments and outcomes in patients with Susac syndrome (SS) (retinocochleocerebral vasculopathy).

METHODS

  A retrospective review was performed of all patients presenting with SS at the Mayo Clinic in Rochester, Minnesota, USA (1 January 1998-1 October 2011).

RESULTS

  There were 29 cases of SS (24 women, mean age at presentation, 35 years; range, 19-65; full triad of brain, eye, and ear involvement, n = 16; mean follow-up time, 29 months). Thirty CSF analyses were performed in 27 cases (mean protein 130 mg/dl, range 35-268; mean cell count 14, range 1-86). MRI of the brain showed corpus callosal involvement (79%), T2-weighted hyperintensities (93%), and gadolinium enhancement (50%). Average lowest modified Rankin Scale score was 2.5 (median 2, range 0-5). Most patients (93%) received immunosuppressive treatment, with a mean time to treatment of 2 months following symptomatic onset. Treatments included intravenous methylprednisolone or dexamethasone (n = 23), oral corticosteroids (n = 24), plasma exchange (PLEX) (n = 9), intravenous immunoglobulin (IVIg) (n = 15), cyclophosphamide (n = 6), mycophenolate mofetil (n = 5), azathioprine (n = 2), and rituximab (n = 1). Most patients also received an antiplatelet agent (n = 21). Improvement or stabilization was noted in eight of 11 cases treated with IVIg in the acute period (three experienced at least partial deterioration) and eight of nine cases of PLEX treatment (one lost to follow up).

CONCLUSIONS

  Susac syndrome may be severe, disabling, and protracted in some patients. PLEX may be an adjunct or alternative therapy for patients who do not experience symptomatic improvement following steroid treatment.

Cerebral corticospinal tract injury resulting from high-voltage electrical shock

Electrical injuries are becoming more common and are increasingly imaged with advanced technologies, such as MR imaging. However, the MR imaging findings of such injuries remain largely unstudied. We report a high-voltage electrical injury to the cerebral corticospinal tracts and document evolution on serial MR images.

Progressive supranuclear palsy phenotype secondary to CADASIL

BACKGROUND AND PURPOSE

To report a unique case of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy manifesting as a progressive supranuclear palsy phenotype, thereby expanding its recognized presentations.

METHODS

Review of the pertinent literature from MEDLINE, cross-referencing cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, progressive supranuclear palsy, and parkinsonism. Description of a 60-year-old woman who presented with a several year history of step-wise, progressive parkinsonism secondary to cerebral autosomal dominant arteriopathy.

RESULTS

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy may present with a progressive supranuclear phenotype.

CONCLUSION

Parkinsonism, including a progressive supranuclear palsy phenotype, is one of a growing number of recognized ways that cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy may present.

Hyperhomocysteinemia in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

OBJECTIVE

To determine whether patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) had evidence of increased homocysteine levels compared with non-CADASIL patients with ischemic stroke or transient ischemic attack.

PATIENTS AND METHODS

We compared fasting plasma homocysteine levels and levels 6 hours after oral loading with methionine, 100 mg/kg, in non-CADASIL patients with ischemic stroke or transient ischemic attack and in patients with CADASIL. Prechallenge, postchallenge, and change in homocysteine levels between the 2 groups were compared with use of the Wilcoxon rank sum test.

RESULTS

CADASIL and non-CADASIL groups were similar in age (mean, 48.8 vs. 46.5 years, respectively; 2-tailed t test, P=.56) and sex (men, 86% vs 59%; Fisher exact test, P=.12). The 59 patients in the CADASIL group had higher median plasma homocysteine levels compared with the 14 patients in the non-CADASIL group, both in the fasting state (12.0 vs 9.0 micromol/L; P=.03) and after methionine challenge (51.0 vs 34.0 micromol/L; P=.007). Median difference between homocysteine levels before and after methionine challenge was greater in the CADASIL group than in the non-CADASIL group (34.5 vs. 24.0 micromol/ L; P = .02).

CONCLUSION

Our findings raise the possibility that increased homocysteine levels or abnormalities of homocysteine metabolism may have a role in the pathogenesis of CADASIL.

Patent foramen ovale transcatheter closure device thrombosis

The role of patent foramen ovale (PFO) in patients with cryptogenic stroke (stroke of unknown cause) remains controversial, although an association seems likely in younger patients with atrial septal aneurysms and PFO. The mechanism of cryptogenic stroke in these patients is presumed to be paradoxical embolism via right-to-left shunt across the PFO. The available options for treatment include medical therapy with antiplatelet or anticoagulant therapy or closure of the PFO surgically or with use of transcatheter PFO closure devices. We describe 2 cases of bilateral device thrombosis associated with use of a transcatheter PFO closure device (CardioSEAL). To our knowledge, only 1 other case of thrombosis associated with use of this device has been reported.

Recurrence of Susac syndrome (retinocochleocerebral vasculopathy) after remission of 18 years

Susac syndrome (retinocochleocerebral vasculopathy) is a syndrome of unknown pathogenesis. The triad of multifocal encephalopathy, visual loss, and hearing loss is caused by microangiopathy of the brain, retina, and cochlea. The illness tends to be monophasic, and to our knowledge, recurrence after years of remission has not been reported. We describe a 51-year-old woman with symptoms, signs, and brain magnetic resonance imaging findings consistent with recurrence of Susac syndrome 18 years after remission. Clinicians should be aware of the possibility of late recurrence of Susac syndrome when evaluating patients with a distant history of the syndrome who present with complaints referable to the brain, retina, and cochlea.

Left atrial volume: important risk marker of incident atrial fibrillation in 1655 older men and women

OBJECTIVE

To evaluate the contribution of left atrial (LA) volume in predicting atrial fibrillation (AF).

PATIENTS AND METHODS

In this retrospective cohort study, a random sample of 2200 adults was identified from all Olmsted County, Minnesota, residents who had undergone transthoracic echocardiographic assessment between 1990 and 1998 and were 65 years of age or older at the time of examination, were in sinus rhythm, and had no history of AF or other atrial arrhythmias, stroke, pacemaker, congenital heart disease, or valve surgery. The LA volume was measured off-line by using a biplane area-length method. Clinical characteristics and the outcome event of incident AF were determined by retrospective review of medical records. Echocardiographic data were retrieved from the laboratory database. From this cohort, 1655 patients in whom LA size data were available were followed from baseline echocardiogram until development of AF or death. The clinical and echocardiographic associations of AF, especially with respect to the role of LA volume in predicting AF, were determined.

RESULTS

A total of 666 men and 989 women, mean +/- SD age of 75.2 +/- 7.3 years (range, 65-105 years), were followed for a mean +/- SD of 3.97 +/- 2.75 years (range, < 1.00-10.78 years); 189 (11.4%) developed AF. Cox model 5-year cumulative risks of AF by quartiles of LA volume were 3%, 12%, 15%, and 26%, respectively. With Cox proportional hazards multivariate models, logarithmic LA volume was an independent predictor of AF, incremental to clinical risk factors. After adjusting for age, sex, valvular heart disease, and hypertension, a 30% larger LA volume was associated with a 43% greater risk of AF, incremental to history of congestive heart failure (hazard ratio [HR], 1.887; 95% confidence interval [CI], 1.230-2.895; P = .004), myocardial infarction (HR, 1.751; 95% CI, 1.189-2.577; P = .004), and diabetes (HR, 1.734; 95% CI, 1.066-2.819; P = .03). Left atrial volume remained incremental to combined clinical risk factors and M-mode LA dimension for prediction of AF (P < .001).

CONCLUSION

This study showed that a larger LA volume was associated with a higher risk of AF in older patients. The predictive value of LA volume was incremental to that of clinical risk profile and conventional M-mode LA dimension.

Predictors of cerebrovascular events and death among patients with valvular heart disease: A population-based study

BACKGROUND AND PURPOSE

There is little population-based information on cerebrovascular events and survival among valvular heart disease patients. We used the Kaplan-Meier product-limit method and the Cox proportional hazards model to determine rates and predictors of cerebrovascular events and death among valve disease patients.

METHODS

This population-based historical cohort study in Olmsted County, Minnesota, reviewed residents with a first echocardiographic diagnosis of mitral stenosis (n=19), mitral regurgitation (n=528), aortic stenosis (n=140), and aortic regurgitation (n=106) between 1985 and 1992.

RESULTS

During 2694 person-years of follow-up, 98 patients developed cerebrovascular events and 356 died. Compared with expected numbers, these observations are significantly elevated, with standardized morbidity ratio of 3.2 (95% CI, 2.6 to 3.8) and 2. 5 (95% CI, 2.2 to 2.7), respectively. Independent predictors of cerebrovascular events were age, atrial fibrillation, and severe aortic stenosis. The risk ratio of severe aortic stenosis was 3.5 (95% CI, 1.4 to 8.6), with atrial fibrillation conferring greater risk at younger age. Predictors of death were age, sex, cerebrovascular events, ischemic heart disease, and congestive heart failure, the greatest risk being among those with both congestive heart failure and cerebrovascular events (risk ratio=8.8; 95% CI, 5. 8 to 13.4). Valve disease type and severity were not independent determinants of death.

CONCLUSIONS

The risk of cerebrovascular events and death among patients with valve disease remains high. Age, atrial fibrillation, and severe aortic stenosis are independent predictors of cerebrovascular events, and age, sex, cerebrovascular events, congestive heart failure, and ischemic heart disease are independent predictors of death in these patients.

Ischemic stroke subtypes : a population-based study of functional outcome, survival, and recurrence

BACKGROUND AND PURPOSE

There is scant population-based information on functional outcome, survival, and recurrence for ischemic stroke subtypes.

METHODS

We identified all residents of Rochester, Minnesota, with a first ischemic stroke from 1985 through 1989 using the resources of the Rochester Epidemiology Project medical records linkage system. After reviewing medical records and imaging studies, we assigned patients to 4 major ischemic stroke categories based on National Institute of Neurological Diseases and Stroke Data Bank criteria: large-vessel cervical or intracranial atherosclerosis with stenosis (ATH, n=74), cardioembolic (CE, n=132), lacunar (LAC, n=72), and infarct of uncertain cause (IUC, n=164). We used the Rankin disability score to assess functional outcome and the Kaplan-Meier product-limit method and Cox proportional hazards regression analysis with bootstrap validation to estimate rates and identify predictors of survival and recurrent stroke among these patients.

RESULTS

Rankin disabilities were different across stroke subtypes at the time of stroke and 3 months and 1 year later (P=0.001). LAC was associated with milder deficits compared with other subtypes. Mean follow-up among the 442 patients in the cohort was 3.2 years. Estimated rates of recurrent stroke at 30 days were significantly different (P<0.001): ATH, 18.5% (95% CI 9.4% to 27.5%); CE, 5.3% (95% CI 1.2% to 9.6%); LAC, 1.4% (95% CI 0.0% to 4.1%); and IUC, 3. 3% (95% CI 0.4% to 6.2%). After adjusting for age, sex, and stroke severity, infarct subtype was an independent determinant of recurrent stroke within 30 days (P=0.0006; eg, risk ratio for ATH compared with CE=3.3, 95% CI 1.2 to 9.3) but not long term (P=0.07). Four of 25 recurrent strokes within 30 days were procedure-related, each in patients with ATH. Five-year death rates were significantly different (P<0.001): ATH, 32.2% (95% CI 21.1% to 43.2%); CE, 80.4% (95% CI 73.1% to 87.6%); LAC, 35.1% (95% CI 23.6% to 46.0%); and IUC, 48.6% (95% CI 40.5% to 56.7%). With adjustment for age, sex, cardiac comorbidity, and stroke severity, the subtype of ischemic stroke was an independent determinant of long-term (P=0.018; eg, risk ratio for ATH compared with cardioembolic=0.47, 95% CI 0.29 to 0.77) but not 30-day survival (P=0.2).

CONCLUSIONS

Early recurrence rates for ischemic stroke caused by ATH are higher than those for other subtypes and higher than previous non-population-based studies have reported. Some of the increased risk of early recurrence among patients with ATH may be iatrogenic. Patients with LAC have better poststroke functional status than those with other subtypes. Survival is poorest among those with ischemic stroke with a cardiac source of embolism.

Ischemic stroke subtypes: a population-based study of incidence and risk factors

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.

Comparison of population-based models of risk factors for TIA and ischemic stroke

OBJECTIVE

To determine whether there is a difference in the risk factors for ischemic stroke and for TIA.

BACKGROUND

TIA is associated with a high risk for ischemic stroke, but some have considered TIA as mild ischemic stroke. Prevention of disabling stroke is sufficient reason to label TIA as a precursor for stroke, but some risk factors may be more or less associated with TIA than with ischemic stroke, suggesting differences in mechanism.

METHODS

The medical records linkage system for the Rochester Epidemiology Project provided the means of identifying first episodes of TIA in the Rochester, MN population among those who had not had ischemic stroke. Control subjects were selected from an enumeration of the population through the medical records. The exposure to various risk factors was ascertained. The conditional likelihood approach to estimate the parameters of a multiple logistic model permitted estimation of the OR for TIA for each risk factor while adjusting for confounding variables.

RESULTS

The multivariable logistic regression model for TIA shows that the estimates of the ORs for ischemic heart disease, hypertension, persistent atrial fibrillation, diabetes mellitus, and cigarette smoking are similar to the ORs for those variables in the ischemic stroke model. However, the OR for mitral valve disease in the TIA model is 0.4, suggesting that mitral valve disease is unlikely to be associated with cerebral ischemic episodes that are brief enough to be called TIA.

Use of nursing home after stroke and dependence on stroke severity: a population-based analysis

BACKGROUND AND PURPOSE

There are few population-based data available regarding nursing home use after stroke. This study clarifies the use of a nursing home after stroke, as well as its dependence on stroke severity, in a defined population.

METHODS

All first stroke events among residents of Rochester, Minn, during 1987-1989 were ascertained, subtyped, and assigned Rankin disability scores (RS) before the event, at maximal deficit, and at specified intervals after stroke. Persons were followed from the date of stroke event to death, emigration from Rochester, or December 31, 1994, in complete community-based medical records and Minnesota Case Mix Review Program data tapes to determine nursing home residency before stroke and at 90 days and 1 year after stroke, proportion of survival days in a nursing home, and cumulative risk of admission to a nursing home.

RESULTS

There were 251 cases of first cerebral infarction, 24 intracerebral hemorrhages, and 15 subarachnoid hemorrhages among residents of Rochester during 1987-1989. The maximal deficit RS was 1 or 2 for 62 (25%), RS 3 for 72 (29%), and RS 4 or 5 for 117 (47%) of the cerebral infarct patients. Among patients surviving to 90 days or 1 year after cerebral infarction, 25% were in nursing home at 90 days and 22% at 1 year, respectively. Within these maximal deficit RS categories, the percentages of follow-up time spent in a nursing home during the first post-cerebral infarction year are as follows: RS 1 to 2, 4%; RS 3, 10%; and RS 4 to 5, 54%. Multivariate logistic regression revealed that increasing age and RS 4 to 5 at maximal deficit were independent predictors (P<0.0001) of nursing home residency at 90 days and 1 year after stroke, whereas stroke type was not an independent predictor. At 1 year after cerebral infarction, the Kaplan-Meier estimates of proportion of people with at least 1 nursing home admission were 11% for RS 1 to 2, 22% for RS 3, and 68% for RS 4 to 5.

CONCLUSIONS

This study provides unique population-based data regarding the short- and long-term use of a nursing home after stroke and its dependence on stroke severity. More than 50% of people with a severe cerebral infarction are in a nursing home 90 days and 1 year after the stroke, and by 1 year, nearly 70% will have required some nursing home stay. Age and stroke severity are independent predictors of nursing home residency after stroke.

Cerebrovascular regulation in the postural orthostatic tachycardia syndrome (POTS)

Patients with the postural orthostatic tachycardia syndrome (POTS) have symptoms of orthostatic intolerance despite having a normal orthostatic blood pressure (BP), which suggests some impairment of cerebrovascular regulation. Cerebrovascular autoregulation refers to the maintenance of normal cerebral blood flow in spite of changing BP. Mechanisms of autoregulation include myogenic, metabolic and neurogenic vasoregulation. Beat-to-beat recording of blood-flow velocity (BFV) is possible using transcranial Doppler imaging. It is possible to evaluate autoregulation by regressing deltaBFV to deltaBP during head-up tilt. A number of dynamic methods, relating deltaBFV to deltaBP during sudden induced changes in BP by occluding then releasing peripheral arterial flow or by the Valsalva maneuver. The deltaBFV to deltaBP provides an index of autoregulation. In orthostatic hypotension, the autoregulated range is typically expanded. In contrast, paradoxical vasoconstriction occurs in POTS because of an increased depth of respiration, resulting in hypocapnic cerebrovascular constriction, and impaired autoregulation.

Frequency of major complications of aspirin, warfarin, and intravenous heparin for secondary stroke prevention. A population-based study

BACKGROUND

Complication rates of medical therapy for secondary stroke prevention derived from clinical trials may or may not be applicable to patients with cerebrovascular disease in the general population.

OBJECTIVE

To determine complication rates for aspirin, warfarin, and intravenous heparin administered for secondary stroke prevention after first episodes of ischemic stroke, transient ischemic attack, or amaurosis fugax in a community.

DESIGN

Population-based historical cohort study.

SETTING

Rochester, Minnesota.

PATIENTS

All residents of Rochester who, between 1985 and 1989, received aspirin (n = 339) or warfarin (n = 145) within 2 years after first ischemic stroke, transient ischemic attack, or amaurosis fugax or received intravenous heparin (n = 201) within 2 weeks after first ischemic stroke, transient ischemic attack, or amaurosis fugax.

MEASUREMENTS

Occurrence of major complications caused by therapy.

RESULTS

Twenty aspirin-associated complications (1 fatal) occurred during an average 1.7 years of treatment, 8 warfarin-associated complications occurred during an average 0.7 years of treatment, and 3 heparin-associated complications (1 fatal) occurred during an average 5.1 days of treatment. Complication rates were 3.5 per 100 person-years (95% CI, 2.1 to 5.4) for aspirin, 7.9 per 100 person-years (CI, 3.4 to 15.6) for warfarin, and 0.30 (CI, 0.06 to 0.86) per 100 person-days for heparin. Rates of fatal complications were 0.2 per 100 person-years (CI, 0 to 1.0) for aspirin, 0 per 100 person-years (CI, 0 to 3.6) for warfarin, and 0.10 per 100 person-days (0 to 0.55) for heparin.

CONCLUSIONS

Complication rates for warfarin and intravenous heparin given as therapy for secondary stroke prevention in Rochester, Minnesota, were lower than rates reported from earlier trials and observational studies. However, complication rates for warfarin were higher than in more recent referral-based studies and multicenter randomized trials. After adjustment for duration of therapy, complication rates for heparin were higher than those for aspirin or warfarin. These rates can be used to judge the applicability of complication rates derived from ongoing clinical trials.

Incidence of transient ischemic attack in Rochester, Minnesota, 1985-1989

BACKGROUND AND PURPOSE

There is scant information available on the incidence of transient ischemic attack (TIA) in a defined population. This study defines incidence rates of first TIA and subtypes of TIA during 1985-1989 and compares the incidence to that obtained from a 1960-1972 cohort study.

METHODS

Medical records of all residents of Rochester with potential diagnosis of TIA during 1985-1989 were screened to determine whether the case met the criteria for TIA. All available data were used to determine the vascular distribution of the TIA. Average annual age- and sex-adjusted incidence rates were calculated for 1985-1989, and results were compared with incidence rates determined in a Rochester-based 1960-1972 cohort study. RESILTS: Two hundred two cases of first TIA or amaurosis fugax occurred among Rochester residents during 1985-1989. The age- and sex-adjusted incidence rate for any TIA was 68/100 000 population. Incidence of amaurosis fugax was 13/100 000; anterior circulation (cerebral) TIA, 38/100 000; and vertebrobasilar distribution TIA, 14/100 000. Rates were similar to those determined from a 1960-1972 cohort study.

CONCLUSIONS

The incidence rate of TIA is 41% that of stroke incidence. TIA incidence in Rochester, Minn, is higher than has been previously reported for other sites throughout the world. Although comparison with prior time periods is difficult because of ascertainment issues, it appears that there has been no significant change in TIA incidence since the decade of the 1960s or earlier. This suggests that the most common mechanism for TIA (atherosclerosis) has not changed in prevalence, nor have risk factors leading to this mechanism.

Ischemic stroke: outcomes, patient mix, and practice variation for neurologists and generalists in a community

A variety of methods was used to compare patient mix, practice variation, survival, and recurrence after first ischemic stroke among Rochester, MN residents. The significance of the results for neurologists and generalists was examined. Age, stroke severity, congestive heart failure (CHF), and the interaction between atrial fibrillation and patient groups were determinants of survival. Without atrial fibrillation, patients on neurology services and patients on general services with neurology consultation had better survival than those without neurology consultation, adjusting for age, stroke severity, and CHF. With atrial fibrillation, patients on general services with neurology consultation had no better survival compared with those without neurology consultation; patients on neurology services had worse survival (p=0.002). There was no difference in stroke recurrence. Evaluation by a neurologist is associated with better survival for most patients with ischemic stroke but not those with atrial fibrillation. Only a randomized trial can determine whether this association is causal.

Dolichoectasia of the intracranial arteries in patients with first ischemic stroke: a population-based study

OBJECTIVE

The objective of this study was to estimate the frequency of intracranial arterial dolichoectasia among patients with first ischemic stroke and to compare clinical characteristics, survival, and recurrence in those with and without the abnormality.

BACKGROUND

Dolichoectasia may cause cerebral infarction by thrombosis, embolism, stenosis, or occlusion of deep penetrating arteries.

METHODS

The chi-square, Fisher's exact, and logrank tests were used to compare clinical characteristics, survival, and recurrence for patients with and without dolichoectasia among the 387 residents of Rochester, MN, who had brain CT or MRI for first cerebral infarction from 1985 through 1989.

RESULTS

Twelve patients (3.1%) had dolichoectasia. Patients with dolichoectasia were more likely to have had stroke fitting a clinical and radiographic pattern of lacunar infarction than those without (42% and 17% respectively; p=0.04). Dolichoectasia was detected in the vertebrobasilar system in eight patients (66.7%), in the carotid system in two patients (16.7%), and in both circulatory systems in two patients (16.7%). There were no significant differences in the following characteristics among those with and without dolichoectasia: age, sex, hypertension, diabetes, smoking, and preceding transient ischemic attack. Patients with dolichoectasia had better survival (relative risk [RR] for death, 0.26; p=0.04) after first cerebral infarction but higher rates of stroke recurrence (RR, 2.4; p=0.02).

CONCLUSIONS

Dolichoectasia is detected in 38 of patients with first cerebral infarction and is associated with better survival but higher rates of stroke recurrence.

Survival and recurrence after first cerebral infarction: a population-based study in Rochester, Minnesota, 1975 through 1989

We used the Kaplan-Meier product limit method to estimate rates and Cox proportional hazards regression analysis with bootstrap validation to model significant independent predictors of and temporal trends in survival and recurrent stroke among 1,111 residents of Rochester, MN, who had a first cerebral infarction from 1975 through 1989. The risk of death after first cerebral infarction was 7% +/- 0.7% at 7 days, 14% +/- 1.0% at 30 days, 27% +/- 1.3% at 1 year, and 53% +/- 1.5% at 5 years. Independent risk factors for death after first cerebral infarction were age (p < 0.0001), congestive heart failure (p < 0.0001), persistent atrial fibrillation (p < 0.0001), recurrent stroke (p < 0.0001), and ischemic heart disease (p < 0.0001 for age < or =70, p > 0.05 for age >70). The risk of recurrent stroke after first cerebral infarction was 2% +/- 0.4% at 7 days, 4% +/- 0.6% at 30 days, 12% +/- 1.1% at 1 year, and 29% +/- 1.7% at 5 years. Age (p = 0.0002) and diabetes mellitus (p = 0.0004) were the only significant independent predictors of recurrent stroke. Neither the year nor the quinquennium of the first cerebral infarction was a significant determinant of survival or recurrence. The temporal trend toward improving survival after first cerebral infarction documented in Rochester, MN, in the decades before 1975 has ended.

Retinocochleocerebral vasculopathy

We report 10 patients with retinocochleocerebral vasculopathy and review the clinical and diagnostic considerations in previously reported patients with this uncommonly recognized disease. The clinical manifestations include acute and subacute multifocal and diffuse encephalopathic symptoms, hearing loss, and visual loss attributable to microangiopathy affecting the arterioles of the brain, retina, and cochlea. Diagnosis is facilitated by demonstration of retinal arteriolar occlusions without uveitis or keratoconjunctivitis, mid- to low-frequency unilateral or bilateral sensorineural hearing loss, and numerous small foci of increased signal in the white and gray matter on T2 weighted brain magnetic resonance imaging. Because many conditions may produce any combination of strokelike cerebral symptoms, encephalopathy, hearing loss, and visual loss, the differential diagnosis for retinocochleocerebral vasculopathy includes connective tissue disease, demyelinating disease, procoagulant state, infection, neoplasm, and more routine mechanisms of cerebral and retinal ischemia. Brain biopsy specimens demonstrate only minimal nonspecific periarteriolar chronic inflammatory cell infiltration with or without microinfarcts. The demonstration of subclinical arteriolar microangiopathy in muscle biopsy specimens, documented in 3 of our patients may assist in making the diagnosis. The clinical course appears to be monophasic. In addition to corticosteroids, treatment options include immunosuppressant agents (cyclophosphamide or azathioprine) aspirin, calcium channel blockers (nimodipine), intravenous immunoglobulin, and plasmapheresis. The etiology of the disease is unknown, but histopathologic and laboratory evidence suggests that an immune-mediated mechanism may be involved.

Patent foramen ovale in patients with cerebral infarction. A transesophageal echocardiographic study

OBJECTIVES

To determine the frequency of patent foramen ovale (PFO) among various subtypes of cerebral infarction. To determine whether any historical or clinical characteristics predict the presence or absence of PFO in these patients.

DESIGN

Comorbidity and infarct subtype study.

SETTING

Referral-based study.

PATIENTS

One hundred sixteen patients with cerebral infarction consecutively referred for transesophageal echocardiography during a 6-month period.

MAIN OUTCOME MEASURES

Infarct subtype classification was made using a clinical and radiographic diagnostic rubric similar to that used by the Stroke Data Bank of the National Institute of Neurological Diseases and Stroke. The frequency of various risk factors and clinical characteristics in patients with and in those without PFO and the frequency of PFO in patients with various infarct subtypes were compared (chi 2 or Fisher exact tests).

RESULTS

Patent foramen ovale was detected in 37 patients (32%). Mean age was similar in those with (60 years) and those without (64 years) PFO. Patent foramen ovale was more frequent among men (39%) than women (20%, P = .03). Patients with PFO had a lower frequency of atrial fibrillation, diabetes mellitus, hypertension, and peripheral vascular disease compared with those without PFO. There was no difference in frequency of the following characteristics in patients with PFO compared with those without PFO: pulmonary embolus, chronic obstructive pulmonary disease, pulmonary hypertension, peripheral embolism, prior cerebral infarction, nosocomial cerebral infarction, Valsalva maneuver at the same time of cerebral infarction, recent surgery, or hemorrhagic transformation of cerebral infarction. Patent foramen ovale was found in 22 (40%) of 55 patients with infarcts of uncertain cause and in 15 (25%) of 61 with infarcts of known cause (cardioembolic, 21%; large vessel atherostenosis, 25%; lacune, 40%) (P = .08). When the analysis was restricted to patients who underwent Valsalva maneuver, PFO with right to left or bidirectional shunt was found in 19 (50%) of 38 patients with infarcts of uncertain cause and in 6 (20%) of 30 with infarcts of known cause (P = .01).

CONCLUSION

Although PFO was overrepresented in patients with infarcts of uncertain in our and other studies, it has a high frequency among patients with cerebral infarction of all types. The relation between PFO and stroke requires further study.

Cerebral ischemia in patients with hepatitis C virus infection and mixed cryoglobulinemia

We describe two women (ages 35 and 36 years) with cerebral ischemia, hepatitis C virus, and mixed cryoglobulinemia. One patient (case 1) was in otherwise good health when left parietal cerebral infarction developed, and she was found to have narrowing of the supraclinoid internal carotid artery siphon, anterior cerebral artery A1, and middle cerebral artery M1 segments bilaterally. Subsequent evaluation revealed abnormal liver enzymes, mixed cryoglobulinemia (type III), hypocomplementemia, and a high positive test result for rheumatoid factor. In the other patient (case 2), cerebral ischemia and seizures developed in the setting of previously documented mixed cryoglobulinemia (type II), membranoproliferative glomerulonephritis, and hypocomplementemia. In this patient, a brain biopsy demonstrated cerebral infarction. Hepatitis C virus infection was confirmed in both patients by polymerase chain reaction detection of hepatitis C virus RNA. These two cases document the occurrence of cerebral ischemia in patients with hepatitis C virus infection and mixed cryoglobulinemia. Testing for hepatitis C virus and cryoglobulins should be considered in selected patients with cerebral ischemia of inobvious cause.

Electroencephalography in lacunar infarction

To determine the occurrence and clinical implications of electroencephalographic (EEG) abnormalities in patients with acute lacunar infarction, we conducted a single-blinded EEG study in 55 patients. Twenty-nine (53%) had mild EEG abnormalities, which were focal and ipsilateral to the side of infarction in 7 patients (13%). Abnormalities were more common in patients with evidence of a prior stroke (10 of 12 patients, 83%). However, 43% (16 of 37 patients) of those without historical or radiologic evidence of a prior stroke also had mild EEG abnormalities. This represents a higher incidence of routine EEG abnormalities in lacunar infarction than is generally assumed. Indeed, these findings are more consistent with recent quantitative EEG studies that consistently have shown high rates of abnormalities in lacunar infarction. We did not find major EEG abnormalities, such as continuous or nearly continuous focal delta activity, in any patient with first lacunar infarction. We conclude that within the first 48 h after a first ischemic infarction, when computed tomography often fails to show abnormalities, an EEG that shows lateralized major abnormalities is useful in excluding the diagnosis of either lacunar infarction or infarction limited to the brain stem. Mild abnormalities occur more often than previously thought in lacunar infarction and do not exclude this diagnosis.

Mitral valve prolapse and the risk of stroke after initial cerebral ischemia

Referral-based studies suggest that patients with cerebral ischemia and mitral valve prolapse are prone to recurrent cerebral ischemic events. Our purpose was to determine the risk of subsequent stroke in a population-based group of patients with ischemic stroke or TIA and mitral valve prolapse. From 1975 through 1990, 49 residents of Olmsted County, MN, had an initial ischemic stroke or TIA and echocardiographically diagnosed mitral valve prolapse. Risk of subsequent stroke in this cohort was compared with the age- and sex-adjusted rates of recurrent stroke after initial cerebral ischemia in the Rochester, MN, population. Mean age of the patients was 72 years. Thirty-one (63%) were women. Nine had subsequent stroke (5.5 per 100 person-years). For Rochester patients who had initial ischemic stroke in the period 1975 through 1984, 10.72 recurrent strokes were expected (relative risk, 0.84; 95% confidence limits, 0.38 to 1.59). For Rochester patients with initial ischemic stroke or TIA in the period 1975 through 1979, 12.31 recurrent strokes were expected (relative risk, 0.73; 95% confidence limits, 0.33 to 1.39). There is no evidence of increased subsequent stroke risk among patients with initial episodes of cerebral ischemia and mitral valve prolapse relative to the age- and sex-adjusted recurrent stroke rates in the community.

Risk of stroke with mitral valve prolapse in population-based cohort study

BACKGROUND AND PURPOSE

The purpose of this study was to clarify whether mitral valve prolapse increases the subsequent risk of stroke.

METHODS

A historical cohort study was conducted on 1079 residents of Olmsted County, Minnesota, who had an initial echocardiographic diagnosis of mitral valve prolapse between 1975 and 1989 without prior stroke or transient ischemic attack and who were followed up for first stroke occurrence.

RESULTS

There was an overall twofold increase in the incidence of stroke among individuals with mitral valve prolapse relative to the reference population (standardized morbidity ratio, 2.1; 95% confidence interval, 1.3 to 3.2). Sex, duration of follow-up from the diagnosis of mitral valve prolapse, or calendar year of initial diagnosis did not modify the association. Within the cohort of patients who were at least 35 years old at diagnosis of mitral valve prolapse, a time-dependent proportional-hazards multivariate model and a person-years analysis revealed that age, ischemic heart disease, congestive heart failure, and diabetes mellitus were important determinants for stroke when person-years of observation after mitral valve replacement were excluded. Among seven persons with mitral valve replacement, three strokes occurred in 24 person-years of follow-up. For those with an auscultatory diagnosis of mitral valve prolapse only as the indication for echocardiography (44%), the risk of stroke relative to the population was 1.0 (95% confidence interval, 0.2 to 2.9); for those with another cardiac diagnosis, the standardized morbidity ratio was 2.5 (95% confidence interval, 1.5 to 4.0).

CONCLUSIONS

Individuals with uncomplicated mitral valve prolapse did not have an increased risk of stroke, although a small increase in the risk may not have been detected.

Transient ischemic attack and minor ischemic stroke: an algorithm for evaluation and treatment. Mayo Clinic Division of Cerebrovascular Diseases

OBJECTIVE

To report a cost-effective and scientifically based algorithm for the clinical assessment and treatment of patients with transient ischemic attack (TIA) or minor ischemic stroke.

DESIGN

We comprehensively reviewed the literature on the epidemiologic features, assessment approaches, and treatment recommendations for ischemic cerebrovascular disease and developed an algorithm by using the available clinical and research data to support all decision-making steps.

MATERIAL AND METHODS

For patients with TIA or minor ischemic stroke, the appropriate setting for investigation (inpatient or outpatient), suggested diagnostic tests, use of anticoagulants and antiplatelet agents, and indications for surgical treatment are reviewed.

RESULTS

Although stroke is a common cause of death and lost productivity in the United States, the clinical assessment of patients with TIA or minor ischemic stroke has lacked consistency. The simplified algorithm clarifies patients who may be candidates for hospitalization and possible anticoagulation therapy. Initial diagnostic studies should include computed tomography of the head without use of a contrast agent, which quickly distinguishes nonhemorrhagic from hemorrhagic cerebrovascular disease. Evolving noninvasive studies of the cerebral vasculature are providing increasingly sensitive means of detecting stenoses, yet cerebral angiography remains the "gold standard." Treatment options depend on the pathophysiologic findings on diagnostic evaluation.

CONCLUSION

The assessment of patients with ischemic cerebrovascular disease is complex. The simplified algorithmic approach reported herein necessitates entry of appropriate patients into the algorithm. Because of clinical heterogeneity, an algorithm may apply to a wide spectrum of patients but will not cover every situation; hence, evaluation must be guided by a patient's unique history and findings on examination and by the physician's clinical experience.

A population-based study of stroke in the setting of mitral valve prolapse: risk factors and infarct subtype classification

OBJECTIVE

To determine the frequency of risk factors and the mechanisms of stroke in patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse in the general population.

DESIGN

We conducted a population-based study in Olmsted County, Minnesota, which encompassed the period from 1975 through 1989.

MATERIAL AND METHODS

Study subjects were identified by using the Rochester Epidemiology Project medical records-linkage system. Cardiac and neurologic data were summarized, and a two-sided chi 2 test or Fisher's exact test was used for statistical analysis.

RESULTS

Among residents of Olmsted County, Minnesota, 33 had echocardiographically diagnosed mitral valve prolapse and a first cerebral infarction between 1975 and 1989. The mean patient age was 71 years, and more than half (52%) were men. Risk factors for stroke included hypertension (55%), smoking (42%), coronary artery disease (27%), atrial fibrillation or flutter (24%), congestive heart failure (21%), hypertensive heart disease (21%), prior myocardial infarction (12%), diabetes (9%), and sick sinus syndrome (3%). Cerebral infarction subtypes were as follows: cardioembolic source (excluding mitral valve prolapse only), 30%; lacuna, 12%; large-vessel atherosclerosis, 9%; other, 6%; and infarction of uncertain cause (including mitral valve prolapse), 42%.

CONCLUSION

Most Olmsted County patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse had other risk factors for stroke, and most had identifiable mechanisms of infarction other than embolism due to mitral valve prolapse.

Transcranial Doppler detection of anterior cerebral artery vasospasm

The performance of transcranial Doppler in the detection of anterior cerebral artery vasospasm and vasospasm in patients after subarachnoid haemorrhage was analysed. Transcranial Doppler and cerebral angiography were performed within the same 24 hours on each of 41 patients with acute subarachnoid haemorrhage. Sensitivity and specificity of transcranial Doppler to classify middle cerebral arteries, anterior cerebral arteries, and patients with angiographic vasospasm were determined at mean velocities of 120 and 140 cm/s. Accuracy of transcranial Doppler was better at 140 than at 120 cm/s. For the middle cerebral artery, sensitivity was 86%, specificity 98%. For the anterior cerebral artery, sensitivity was 13%, specificity 100%. Among all patients, sensitivity was 45%, specificity 96%. Among patients with anterior communicating artery aneurysms, sensitivity was 14%, specificity 90%. Therefore, transcranial Doppler accurately differentiates between middle cerebral arteries with and without vasospasm on angiography, but has a very low sensitivity for detecting anterior cerebral artery vasospasm and vasospasm in patients with anterior communicating artery aneurysms. Since vasospasm may involve anterior cerebral arteries while sparing middle cerebral arteries, especially after rupture of an anterior communicating artery aneurysm, caution should be exercised in using negative transcranial Doppler results to make treatment decisions based on the assumed absence of vasospasm.

Pseudotumor syndrome associated with cerebral venous sinus occlusion and antiphospholipid antibodies

BACKGROUND AND PURPOSE

Antiphospholipid antibodies are known to be associated with increased risk of venous and arterial thrombotic events, including cerebral venous thromboses. Pseudotumor syndrome can be produced by cerebral venous thrombosis. A patient with cerebral venous thrombosis associated with antiphospholipid antibodies who exhibited pseudotumor syndrome is reported.

CASE DESCRIPTION

A 49-year-old man who noted visual blurring and persistent vertical wavy lines in his fields of vision was found to have papilledema. Cerebrospinal fluid values were normal except for an opening pressure increase to 510 mm of fluid. His visual symptoms improved with lumbar puncture and the use of acetazolamide. Imaging studies showed that the transverse sinus was occluded completely on the left and partially on the right and that there was a small left cerebellar cortical venous infarction.

CONCLUSIONS

Antiphospholipid syndrome should be considered in the differential diagnosis of pseudotumor syndrome related to cerebral venous thrombosis.

Vasculitic neuropathy in a patient with cryoglobulinemia and anti-MAG IGM monoclonal gammopathy

A patient with sensorimotor mononeuritis multiplex had a type II cryoglobulin with an IgM kappa M-protein that appeared to contain monoclonal anti-MAG antibodies of the same isotype. A sural nerve biopsy demonstrated necrotizing arteritis and features of both axonal degeneration and demyelination. IgM kappa and C3 deposits were present on the myelin sheath of some residual nerve fibers. The findings suggest that the anti-MAG antibodies contributed to the myelin damage, while cryoprecipitates may have caused the vasculitis and axonal degeneration.

Embolic stroke after smoking "crack" cocaine

A 39-year-old woman had an embolic upper division middle cerebral artery branch occlusion 3 hours after smoking the free base of cocaine ("crack"). Radionuclide ventriculography demonstrated cardiomyopathy, and echocardiography documented a left atrial thrombus. This case demonstrates that embolism is one mechanism of ischemic stroke after cocaine use, and that cardiomyopathy, possibly cocaine induced, may be the source of embolus. A cardiac source of embolus should be sought in patients with cocaine-associated cerebral infarction.

Transcranial Doppler ultrasonography: clinical applications in cerebrovascular disease

Transcranial Doppler ultrasonography was introduced in 1982 as a noninvasive procedure for assessment of the intracranial cerebral circulation. The lightweight and portable equipment used for transcranial Doppler examination facilitates its use in the bedside assessment of critically ill hospitalized patients and outpatients. Clinical applications include the diagnosis of vasospasm in patients with subarachnoid hemorrhage, assessment of intracranial collateral flow in patients with extracranial arterial occlusive disease, detection of intracranial arterial stenosis, identification of the feeding arteries of arteriovenous malformations and monitoring the hemodynamic effects of their treatment, confirmation of the clinical diagnosis of brain death, intensive-care unit monitoring of brain-injured patients, and intraoperative and postoperative monitoring of neurosurgical patients. Transcranial Doppler technology is also providing new insights into the pathophysiologic mechanisms of a variety of cerebrovascular conditions. Clinicians will find transcranial Doppler technology most helpful if they have a specific question about the status of the intracranial circulation. Further investigations may expand the clinical and research utility of this technology.

Fatal or severely disabling cerebral infarction during hospitalization for stroke or transient ischemic attack

Six (1%) of 578 patients admitted for cerebral infarction or transient ischemic attack (TIA) suffered a fatal or severely disabling in-hospital cerebral infarction following a period of stabilization or improvement lasting more than 1 day. These infarctions were characterized by the sudden onset of stupor or coma and subsequent development of transtentorial herniation due to carotid or middle cerebral artery territory infarction, or widespread brain-stem infarction due to basilar occlusion. Only one patient survived. Four patients had large-vessel disease documented by Doppler, angiography, or at autopsy. Each of these six infarcts occurred during the morning hours, 4-9 days after the initial event, 3-8 days after initiation of intravenous heparin, and within 4-8 h after intravenous heparin had been discontinued. No coagulation abnormalities were documented. We believe that these cases indicate that among patients admitted for cerebral infarction or TIA, fatal or severely disabling in-hospital cerebral infarction after a period of stabilization or improvement may occur in patients having an initially mild to moderate clinical deficit, that those suffering large artery disease may be at greater risk, and that there may be a relationship between heparin withdrawal and cerebral infarction in some patients.

Hemodynamic role of ophthalmic artery collateral in internal carotid artery occlusion

We performed duplex and transcranial Doppler studies in 36 patients with angiographically documented internal carotid artery occlusion (ICAO) to determine the effect of ophthalmic artery collateral (OAC) on measures of vascular resistivity both proximal and distal to the occlusion. Resistance in the common carotid artery, measured by the resistivity index, was significantly lower in the group with OAC than in those without OAC, indicating a shunt to the low resistance intracranial circuit. The pulsatility index (PI) of the Doppler signal in the ipsilateral middle cerebral artery, a measure of both inflow pressure and distal vascular resistance, did not differ between those with and without OAC. However, the presence of circle of Willis collateral pathways (anterior communicating and/or posterior communicating artery) did appear to have a significant effect on pulsatility. When both were present angiographically, PI was higher than in the group with only 1 Willisian collateral. These findings suggest that OAC has a marginal effect on vascular resistance in arterial bed distal to an ICAO, while Willisian collaterals appear to have a more important role in cerebral perfusion, as measured indirectly by Doppler methods.

The role of transcranial Doppler in confirming brain death: sensitivity, specificity, and suggestions for performance and interpretation

We performed transcranial Doppler (TCD) examinations on 54 comatose patients over a 1-year period. Of 49 patients with technically adequate TCD examinations, 23 met criteria for determination of brain death by clinical and EEG criteria (21) or clinical criteria alone (2; EEG not performed). A TCD waveform abnormality, consisting of absent or reversed diastolic flow, or small early systolic spikes, in at least 2 intracranial arteries, occurred in 21 brain-dead patients, but in none of the other patients in coma. With appropriate guidelines for performance and interpretation, TCD could be incorporated into institutional protocols as a rapid and convenient alternative to EEG for confirmation of brain death.

Transcranial Doppler ultrasonographic changes after treatment for arteriovenous malformations

We performed transcranial Doppler ultrasonography on 15 patients with arteriovenous malformations before and after embolization or surgical resection to compare quantitatively the hemodynamic effects of these two treatments. Changes in mean blood velocity and pulsatility index were analyzed in 19 treated feeding arteries. Blood velocity decreased by a mean of 38.1% or 46.5 cm/sec (p less than 0.0001, two-tailed paired t test); decreases were greater for surgically resected arteries (46.2% or 55.9 cm/sec, p less than 0.003) than for embolized arteries (30.8% or 38.0 cm/sec, p less than 0.0003). Pulsatility index increased by a mean of 54.7% or 0.25 (p = 0.0001); increases were greater for surgically resected arteries (65.8% or 0.29, p = 0.0045) than for embolized arteries (44.8% or 0.20, p less than 0.001). The differences in the changes in blood velocity and pulsatility index between treatment groups were not significant. These data demonstrate that embolization results in hemodynamic changes that are qualitatively similar to those occurring after surgical resection of arteriovenous malformations. Transcranial Doppler ultrasonography is a reliable and convenient noninvasive method for monitoring hemodynamic effects of treatments for arteriovenous malformations.

Complications of long-term anticoagulation

We used life-table techniques to determine risks of morbidity and mortality associated with long-term warfarin treatment in an anticoagulation clinic. Cumulative risks for life-threatening complications and warfarin-related death among all patients were 1% at 6 months, 5% at 1 year, and 7% at 2 and 3 years. Cox regression analysis using age as a continuous variable failed to show an effect of age on cumulative risks of complication. The occurrence of a minor complication during the course of therapy did not place patients at higher risk for developing a major complication that would prompt discontinuation of therapy or cause death. There was no statistically significant difference between the cumulative risks of patients anticoagulated for cerebrovascular disease and the cumulative risks of patients anticoagulated for other indications.