IPHIE: an International Partnership in Health Informatics Education

Medical informatics contributes significantly to high quality and efficient health care and medical research. The need for well educated professionals in the field of medical informatics therefore is now worldwide recognized. Students of medicine, computer science/informatics are educated in the field of medical informatics and dedicated curricula on medical informatics have emerged. To advance and further develop the beneficial role of medical informatics in the medical field, an international orientation of health and medical informatics students seems an indispensable part of their training. An international orientation and education of medical informatics students may help to accelerate the dissemination of acquired knowledge and skills in the field and the promotion of medical informatics research results on a more global level. Some years ago, the departments of medical informatics of the university of Heidelberg/university of applied sciences Heilbronn and the university of Amsterdam decided to co-operate in the field of medical informatics. Now, this co-operation has grown out to an International Partnership of Health Informatics Education (IPHIE) of 5 universities, i.e. the university of Heidelberg, the university of Heilbronn, the university of Minnesota, the university of Utah and the university of Amsterdam. This paper presents the rationale behind this international partnership, the state of the art of the co-operation and our future plans for expanding this international co-operation.

Simulation to estimate the capacity of a stroke unit

Preceding the implementation of a Stroke Unit (SU), data have been collected and used for building a simulation model of patient flow. This model was subsequently used to estimate the optimal capacity of the SU to be implemented. Because stroke patients require acute hospital care, this implies a highly variable number of immediate admissions. This variability complicates optimizing the capacity. In order to support decisions with regard to staffing (i.e. capacity) of the SU, different scenarios are simulated and compared to provide insight in the trade-off between regular understaffing and a low bed occupancy rate. In 1996 the Department of Neurology of the Academic Medical Center in the Netherlands implemented its SU to improve the quality of care for stroke patients. Data collected in the years 1997 and 1998 that the SU has been operational were evaluated and confirm the predictions made from simulating different scenarios. We conclude that simulation models provide a powerful tool for supporting decision making with regard to resource planning at the departmental level in our hospital.

Very Early Nimodipine Use in Stroke (VENUS): a randomized, double-blind, placebo-controlled trial

BACKGROUND AND PURPOSE

The Very Early Nimodipine Use in Stroke (VENUS) trial was designed to test the hypothesis that early treatment with nimodipine has a positive effect on survival and functional outcome after stroke. This was suggested in a previous meta-analysis on the use of nimodipine in stroke. However, in a recent Cochrane review we were unable to reproduce these positive results. This led to the early termination of VENUS after an interim analysis.

METHODS

In this randomized, double-blind, placebo-controlled trial, treatment was started by general practitioners or neurologists within 6 hours after stroke onset (oral nimodipine 30 mg QID or identical placebo, for 10 days). Main analyses included comparisons of the primary end point (poor outcome, defined as death or dependency after 3 months) and secondary end points (neurological status and blood pressure 24 hours after inclusion, mortality after 10 days, and adverse events) between treatment groups. Subgroup analyses (on final diagnosis and based on the per-protocol data set) were performed.

RESULTS

At trial termination, after inclusion of 454 patients (225 nimodipine, 229 placebo), no effect of nimodipine was found. After 3 months of follow-up, 32% (n=71) of patients in the nimodipine group had a poor outcome compared with 27% (n=62) in the placebo group (relative risk, 1.2; 95% CI, 0.9 to 1.6). A treatment effect was not found for secondary outcomes and in the subgroup analyses.

CONCLUSIONS

The results of VENUS do not support the hypothesis of a beneficial effect of early nimodipine in stroke patients.

Calcium antagonists for ischemic stroke: a systematic review

BACKGROUND AND PURPOSE

Stroke is a common disease, and many trials with calcium antagonists as possible neuroprotective agents have been conducted. The aim of this review is to determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke.

METHODS

Acute stroke trials were identified with help of the Cochrane Collaboration Stroke Group and personal contacts. All randomized trials (published and unpublished) investigating a calcium antagonist (acting on voltage-sensitive calcium channels) were included. Poor outcome, defined as death or dependency in activities of daily living, was used as main outcome. Analyses were, if possible, "intention-to-treat"; pooled relative risks with 95% CIs were calculated.

RESULTS

Forty-seven trials were identified, of which 29 were included (7665 patients). No effect of calcium antagonists on poor outcome at the end of follow-up (relative risk, 1.04; 95% CI, 0.98 to 1.09) or on death at end of follow-up (relative risk, 1.07; 95% CI, 0.98 to 1.17) was found. Sensitivity analyses on route of administration and time interval between stroke and start of treatment showed no effect on outcome. In subgroups of unpublished and methodologically sound trials, a statistically significant negative effect for calcium antagonists was found. This contrasts with results of published trials and trials of moderate or poor methodological quality.

CONCLUSIONS

The presented evidence rules out a clinically important effect of calcium antagonists after ischemic stroke. The large amount of data leads to narrow CIs with no significant heterogeneity, and the overall results are therefore likely to be statistically robust.

Lack of gender difference in acetazolamide-induced cerebral vasomotor reactivity in patients suffering from type-1 diabetes mellitus

The aim of the present work was to investigate the impact of gender on resting cerebral blood flow velocity and cerebrovascular reserve capacity among diabetic patients. Middle cerebral artery mean blood flow velocity (MCAV) was measured in 72 patients suffering from type 1 diabetes mellitus at rest and 5, 10, 15 and 20 min after intravenous administration of 1 g acetazolamide. Cerebrovascular reserve was calculated as the maximal percent increase in MCAV after acetazolamide. Resting MCAV and cerebrovascular reserve capacity were compared between males and females. Resting cerebral blood flow velocity was higher in diabetic females than in males (men, 55.0+/-17.0 cm/s; women, 64.4+/-12.6 cm/s, p=0.0094). Cerebrovascular reserve capacity was similar in diabetic women and men (men, 44.0%+/-18.6%; women, 52.6%+/-32.9%, p=0.17). Comparing MCAV and cerebrovascular reserve capacity among the diabetic subgroups with disease duration < or = 10 years and >10 years, we did not detect any differences between women and men. Duration of diabetes was an important factor in determining cerebrovascular reserve capacity in both sexes: long-term diabetic women and men showed lower CRC values than diabetics with < or = 10 years disease duration. Cerebrovascular reserve capacity is similar in diabetic women and men. Taking into consideration that cerebrovascular reserve is normally higher among women, our finding indicates a relatively more serious worsening of cerebral vasodilatory responses in women suffering from type 1 diabetes.

Clinical meaning of the Stroke-Adapted Sickness Impact Profile-30 and the Sickness Impact Profile-136

BACKGROUND AND PURPOSE

Handicap or health-related quality of life (HRQL) measures are seldom used in stroke trials, although the importance of these measures has been stressed frequently. We studied the clinical meaning of the Stroke-Adapted Sickness Impact Profile-30 (SA-SIP30) and the original SIP136 for use in stroke research.

METHODS

We included 418 patients who had had a stroke 6 months earlier. We studied the associations between the SA-SIP30 and SIP136 scores versus other frequently used outcome measures from the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) (Barthel Index, Rankin Scale) and the HRQL model (health perception items, Euroqol). To interpret the continuous SA-SIP30 and SIP136 scores, we used receiver operating characteristic curve analysis with the aforementioned measures as external criteria.

RESULTS

The psychosocial dimension scores of both SIP versions remained largely unexplained. The physical dimension and total scores of both SIP versions were mainly associated with the disability measures derived from the ICIDH model, as well as with the physical HRQL domains. Most patients with an SA-SIP30 total score >33 or an SIP136 total score >22 had poor health profiles. There were no major differences between the SA-SIP30 and the SIP136, although the SA-SIP30 scores were less skewed toward the healthier outcomes than the SIP136.

CONCLUSIONS

Our study showed that (1) both SIP total scores primarily represent aspects of physical functioning and not HRQL; (2) both SIP versions provide more clinical information than the frequently used disability measures; and (3) the SA-SIP30 should be preferred over the SIP136.

[Calculation of costs of stroke, cost effectiveness of stroke units and secondary prevention in patients after a stroke, as recommended by revised CBO practice guideline 'Stroke']

OBJECTIVE

Economic analyses have been part of the revision of the Dutch multi-disciplinary stroke guidelines. We evaluated the recommendations on stroke units and prevention of stroke recurrencies in terms of medical costs and health effects among stroke patients.

DESIGN

Cost calculation.

METHOD

Mathematical modelling of medical costs per patient and costs per life year gained without severe stroke (Rankin score (> 3)), by age and sex for each guideline.

RESULTS

Lifetime costs of stroke depended on age and sex and vary between 84,000 and 292,000 Dutch guilders (HFL). The cost-effectiveness of stroke units decreases with age and varies between HFL 37,000 and HFL 60,200 with a large uncertainty range. Four of seven options in secondary prevention were cost-effective by previously established criteria (< HFL 40,000 per year gained without severe disease). Acetylsalicylic acid remained the drug of choice for monotherapy with dipyridamol as a second choice in patients without atrial fibrillation. Clopidogrel was not cost-effective at the current cost level. Anticoagulation after stroke in case of atrial fibrillation was cost-effective.

CONCLUSIONS

Given a short hospital stay stroke units can be as affective as other hospital interventions. Acetylsalicylic acid is the most cost effective monotherapy for secondary prevention.

Epidemiology of stroke in The Netherlands from 1972 to 1994: the end of the decline in stroke mortality

In 1994, stroke was responsible for the death of 4,994 men and 7,601 women in the Netherlands, corresponding to 7.5% of all deaths in men and 11.4% in women. Age-adjusted stroke mortality declined by 39% for men and by 45% for women between 1972 and 1994. However, the decline in mortality levelled off after 1987. In contrast to mortality, age-adjusted discharge rates increased by 47% for men and by 28% for women during the study period. The decline in mortality was equally distributed over the age groups, while the increase in the number of hospital admissions was more pronounced in the older age groups. The analyses by diagnostic subgroups of stroke showed the importance of increasing diagnostic capabilities in the hospital setting. The use of diagnostic subgroups in national mortality data was of limited value, illustrated by the fact that 70% of all stroke deaths in 1994 belonged to the ill-defined type of stroke.

Risks and causes of death in a community-based stroke population: 1 month and 3 years after stroke

We performed a community-based study on a cohort of 221 stroke patients followed for 3 years. In this paper, we tried to answer the following questions: Is the risk of dying increased throughout the first 3 years after stroke? What are the causes of death after the 1st month? What factors at stroke onset are independent predictors of early and late mortality? The relative risk of death was estimated using age- and sex-specific mortality rates for the Netherlands. Causes of death were registered by the attending physicians, mostly general practitioners. During the 1st month 26% of the patients died. At 1, 2 and 3 years, the cumulative mortality rates were 37, 46 and 54%, respectively. Stroke patients had an increased risk of dying, approximately twice that of the general population, during the 3 years of follow-up. In women, this increased risk was more pronounced than in men. After 1 month, cardiovascular pathology, stroke and diseases resulting from stroke were the causes of death in 70% of the patients, i.e. substantially higher than in the general population, matched for age and sex. Factors predicting mortality after stroke varied over time. Severity of the stroke, preexisting atrial fibrillation and congestive heart failure were associated with early mortality (within 30 days). For 1-month survivors, incontinence and preexisting atrial fibrillation were associated with mortality in the 1st year after stroke. After 1 year, only age was associated with mortality.

Prevalence of symptomatic intracranial aneurysm and ischaemic stroke in pseudoxanthoma elasticum

BACKGROUND

Pseudoxanthoma elasticum (PXE) is an heritable connective tissue disorder with clinical manifestations of the ocular, dermal, and cardiovascular system. The purpose of this study was to investigate the prevalence of symptomatic intracranial aneurysms (IAs) and ischaemic stroke (IS) in PXE.

METHODS

The records of 100 patients with PXE were retrieved. All patients were contacted and data on complications were collected. The literature was reviewed regarding PXE, ISs, and IAs.

RESULTS

No patient with PXE had a symptomatic IA as presenting symptom. One patient presented with an IS. During follow-up of 94 of the 100 patients (mean follow-up 17.1 years, range 1-49 years), none presented a symptomatic IA (3,168 retrospective patient observation years and 1, 602 prospective patient observation years). Upper gastrointestinal haemorrhage during follow-up occurred in 17 patients, in 1 patient during aspirin use. One patient has IS as presenting symptom and a recurrence during follow-up, and 7 patients had IS during follow-up. All were caused by small-vessel disease. The relative risk of IS in PXE under 65 years compared with the general population was 3.6 (95% confidence interval 3.3-4.0).

CONCLUSIONS

On the basis of the currently available data, an association between symptomatic IAs and PXE is unlikely. However, the incidence of IS, due to small-vessel disease, was increased. Antiplatelet therapy in patients with PXE may lead to a high incidence of upper gastrointestinal haemorrhages.

[CBO guideline 'Stroke' (revision) Dutch Institute for Healthcare Improvement]

The stroke consensus dating from 1991 had to be revised, because of the introduction of new developments in the treatment of patients with stroke. More than 50 representatives from 25 professions and institutions participated. Under methodological assistance of the Dutch Institute for Healthcare Improvement CBO separate working groups (diagnosis, treatment, organization of care, rehabilitation/education, implementation and cost-effectiveness) studied the literature and translated the results into recommendations with explanatory text. The strength of scientific evidence was classified. During a national public meeting the results were discussed. In the field of guideline development cost-effectiveness analyses and specific attention for implementation are new. Care on a stroke unit decreases the risk of mortality, life-long disabilities, and dependence on permanent care with about 20%. Regional stroke services should be instituted, in which continuity and efficient care can be guaranteed. Very early thrombolysis with recombinant tissue plasminogen activator strongly decreases the number of patients dying, or remaining care-dependent in a selected group of appropriate patients. Secondary prevention (lifestyle measures, acetylsalicyclic acid, treatment of hypertension and hypercholesterolaemia, and surgery of the carotids) may decrease the number of residual strokes and myocardial infarctions. In the occurrence of cerebral ischaemia and atrial fibrillation oral anticoagulants are indicated. Early intensive rehabilitation increases the chance of recovery. Silent cognitive defects may hinder rehabilitation. The extensive guideline summarises the scientific literature about treatment of patients with stroke and should serve as a basis for local protocols and appointments.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with increased levels of calcium ions within neurones. Inhibiting this increase could protect neurones and is thought to reduce neurological impairment, disability and handicap after stroke.

OBJECTIVES

The aim of this review is to determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke. The influence of different drugs, dosages, routes of administration, time intervals after stroke and trial design on the risk of poor outcome was investigated.

SEARCH STRATEGY

Relevant trials were identified in the Specialised Register of Controlled Trials (last searched: March 1999).

SELECTION CRITERIA

All truly randomised trials comparing a calcium antagonist with control in patients with acute ischaemic stroke were included.

DATA COLLECTION AND ANALYSIS

Two authors assessed all trials and extracted the data. Poor outcome, defined as death or dependency in activities of daily living, was used as the main outcome. Analyses were, if possible, "intention-to-treat".

MAIN RESULTS

46 trials were identified of which 28 were included (7521 patients). No effect of calcium antagonists on poor outcome at the end of follow-up (OR 1.07, 95% CI 0.97/1.18), or on death at end of follow-up (OR 1.10, 95% CI 0.98/1.24) was found. Intravenous administration (i.v.) of calcium antagonists was associated with an increase in the number of patients with poor outcome compared to oral administration (indirect comparisons). Comparisons of different doses of nimodipine suggested that the highest doses were associated with poorer outcome. Administration within 12 hours of onset was associated with an increase in the proportion of patients with poor outcome, but this effect was largely due to the poor results associated with i.v. administration. A subgroup analysis on nimodipine (oral, 120 mg/day) started within 12 hours of stroke onset, did not show a beneficial effect.

REVIEWER'S CONCLUSIONS

No evidence is available to justify the use of calcium antagonists in patients with acute ischaemic stroke.

MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement

OBJECTIVE

MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with Subarachnoid hemorrhage) Study Group.

SUBJECTS AND METHODS

We screened 626 first-degree relatives of a consecutive series of 193 patients with subarachnoid hemorrhage examined at two institutions. We used MR imaging and MR angiography (three-dimensional time-of-flight imaging at both institutions and additional three-dimensional phase-contrast imaging at one institution). Three observers independently assessed the MR angiograms. Conventional angiography was performed in relatives with possible or definite aneurysms on MR angiography and was considered the standard of reference.

RESULTS

Thirty-three aneurysms were found in 25 (4%; 95% confidence interval [CI], 3-6%) of 626 relatives. Thirteen (8%) of 169 relatives who refused screening had MR-related reasons; an additional six persons could not be screened because of contraindications for MR imaging (pregnancy, n = 1; claustrophobia, n = 5). The positive predictive value of MR angiography was 100% (95% CI, 79-100%) for "definite" aneurysms and 58% (95% CI, 28-85%) for "possible" aneurysms. Sensitivity of MR angiography was estimated at 83% (95% CI, 65-94%) and specificity at 97% (95% CI, 94-98%). Interobserver agreement in the evaluation of MR angiograms was poor (kappa < .30), probably because different diagnostic strategies used by individual observers resulted in different use of the assessment category "possible aneurysm."

CONCLUSION

MR angiography is a feasible screening tool for detection of intracranial aneurysms. Positive predictive value, sensitivity, and specificity are acceptable when at least two neuroradiologists independently assess MR angiograms.

No relationship between cerebral blood flow velocity and cerebrovascular reserve capacity and contemporaneously measured glucose and insulin concentrations in diabetes mellitus

Blood glucose and insulin concentrations have been reported to influence cerebral hemodynamics. We studied the relationship between actual blood glucose and insulin concentrations and resting cerebral blood flow velocity in the middle cerebral artery and cerebrovascular reserve capacity after acetazolamide stimulation. Thirty-six insulin-dependent diabetic patients in a state of good glycemic control were studied. Blood samples were taken for determination of glucose and insulin concentrations. Subsequently we measured resting cerebral blood flow velocities in supine position using transcranial Doppler, administered 1 g acetazolamide intravenously, and repeated the measurements after 5, 10, 15 and 20 minutes. Cerebrovascular reserve was calculated as the maximal percent increase after acetazolamide stimulation. Multiple regression was used for statistical analysis. Blood glucose levels were not correlated with resting blood flow velocity (R = 0.21, p = 0.22) nor cerebrovascular reserve capacity (R = 0.17, p = 0.32). Similarly, no correlation was found between insulin concentrations, resting cerebral blood flow velocity (R = 0.24, p = 0.22) and cerebrovascular reserve (R = 0.26, p = 0.24). Studying patients with long-term (> 10 years) and short-term (</= 10 years) disease duration yielded the same lack of correlation. We conclude that there is no significant correlation between contemporaneously measured glucose and insulin concentrations and either cerebral blood flow velocity or cerebrovascular reserve capacity in the middle cerebral artery in type 1 diabetic patients with good control.

Type III collagen deficiency in saccular intracranial aneurysms. Defect in gene regulation?

BACKGROUND AND PURPOSE

We sought to determine whether there are mutations in the COL3A1 gene in patients with saccular intracranial aneurysms with a type III collagen deficiency and whether there is an association between a marker in the COL3A1 gene and saccular intracranial aneurysms. One of the heritable factors possibly involved in the pathogenesis of saccular intracranial aneurysms is a reduced production of type III collagen, demonstrated earlier by protein studies.

METHODS

We analyzed the type III collagen gene in a group of 41 consecutive patients with an intracranial aneurysm, of whom 6 patients had shown a reduced production of type III collagen in cultured diploid fibroblasts from a skin biopsy.

RESULTS

No mutations could be demonstrated in the COL3A1 gene, especially not in the globular N- and C-terminal regions. A null allele was excluded in 25 patients, including 1 patient with a decreased type III collagen production. No differences were found between 41 patients and 41 controls in allele frequencies of a DNA tandem repeat polymorphism located in the COL3A1 gene.

CONCLUSIONS

It is concluded that the COL3A1 gene is not directly involved in the pathogenesis of most of intracranial aneurysms. The reduced type III collagen production in cultured fibroblasts found in some patients with an intracranial aneurysm is not explained by the present study and needs further exploration.

Cerebrovascular reactivity and reserve capacity in type II diabetes mellitus

The aim of the study was to test the hypothesis that cerebrovascular reserve capacity and cerebrovascular reactivity are impaired in patients suffering from non insulin-dependent diabetes mellitus. We also intended to investigate factors which may influence resting cerebral blood flow velocity and cerebrovascular reserve capacity. A total of 28 patients suffering from type II diabetes mellitus and 20 healthy control subjects were studied. Based on diabetes duration patients were divided into two groups: subjects with > 10 years and those with < or = 10 years disease duration. Middle cerebral artery mean blood flow velocities were measured at rest and after intravenous administration of 1g acetazolamide. Cerebrovascular reactivity and reserve capacity were calculated. Blood glucose, insulin, glycosylated hemoglobin, hemostatic factors (fibrinogen, alpha-2 macroglobulin and von Willebrand factor antigen) were determined. Cerebrovascular reactivity and reserve capacity values were compared between the two diabetic subgroups and controls. Correlations between laboratory parameters and cerebrovascular reserve were investigated by linear regression analysis. Resting cerebral blood flow velocity was similar in controls and in the two diabetic subgroups. Cerebrovascular reactivity was elevated for a shorter time in patients with > 10 years disease duration than in controls and short-term diabetic patients. Cerebrovascular reserve capacity was lower in the long-term diabetes group (means +/- SD: 39.6 +/- 20.7%) than in patients with < or = 10 years disease duration (63.3 +/- 17.4%, p < 0.02 after Bonferroni correction). Cerebrovascular reserve capacity was inversely related to the duration of the disease (R = 0.53, p < 0.003). None of the determined laboratory factors had any relation with resting cerebral blood flow and cerebrovascular reserve capacity. The vasodilatory ability of cerebral arterioles is diminished in long-standing type II diabetes mellitus.

Unmet care demands as perceived by stroke patients: deficits in health care?

OBJECTIVES

To describe unmet care demands as perceived by stroke patients and to identify sociodemographic and health characteristics associated with these unmet demands to investigate the appropriateness of health care.

SETTING

Sample of patients who participated in a multicentre study (23 hospitals) on quality of care in The Netherlands.

PATIENTS

Non-institutionalised patients who had been admitted to hospital because of stroke. Patients were interviewed six months (n = 382) and five years (n = 224) after stroke.

DESIGN

Six months after stroke data were collected on: (a) sociodemographic characteristics in terms of age, sex, living arrangement, educational level, and regional level of urbanisation; (b) health characteristics in terms of cognitive function, disability, emotional distress, and general health perception; (c) utilisation of professional care; and (d) unmet care demands as perceived by patients. Data on utilisation of care and unmet demands were also collected five years after stroke. Data were collected from June 1991 until December 1996.

RESULTS

The percentage of unmet care demands was highest at six months after stroke (n = 120, 31%). Multiple logistic regression analyses showed that disabled patients were more likely to be unmet demanders for therapy, (I)ADL care and aids (range odds ratio (OR) = 3.5 to 7.9) than to be no demanders, whereas emotionally distressed patients were more likely to be unmet demanders for psychosocial support (OR = 3.8). When comparing unmet demanders with care users only for (instrumental) activities of daily living (I)ADL care differences were found: men (OR = 3.8), disabled patients (OR = 3.0), and emotionally distressed patients (OR = 6.5) were more likely to be users.

CONCLUSIONS

Patients who perceived an unmet care demand do appear genuinely to have an unmet care need as supported by assessment of their health status: (a) types of unmet care demands correspond with types of health problems and (b) unmet demanders were in general unhealthier than no demanders and more comparable with care users for health characteristics.

IMPLICATIONS

To improve an equitable distribution of healthcare services, guidelines for indicating and allocating health care have to be developed and should be based on scientific evidence and consensus meetings including professionals' and patients' perspectives.

Mortality and morbidity of surgery for unruptured intracranial aneurysms: a meta-analysis

BACKGROUND AND PURPOSE

Greater availability and improvement of neuroradiological techniques have resulted in more frequent detection of unruptured aneurysms. Because prognosis of subarachnoid hemorrhage is still poor, preventive surgery is increasingly considered as a therapeutic option. Elective surgery requires reliable data on its risks. Therefore, we performed a meta-analysis on the mortality and morbidity of surgery for unruptured intracranial aneurysms.

METHODS

Through Medline and additional searches by hand, we retrieved studies on clipping of unruptured (additional, symptomatic, or incidental) aneurysms published from 1966 through June 1996. Two authors independently extracted data. We used weighted linear regression for data analysis.

RESULTS

We included 61 studies that involved 2460 patients (57% female; mean age, 50 years) and at least 2568 unruptured aneurysms (27% >25 mm, 30% located in the posterior circulation). Mortality was 2.6% (95% confidence interval [CI], 2.0% to 3.3%). Permanent morbidity occurred in 10.9% (95% CI, 9.6% to 12.2%) of patients. Postoperative mortality was significantly lower in more recent years for nongiant aneurysms and aneurysms with an anterior location; the last 2 characteristics were also associated with a significantly lower morbidity.

CONCLUSIONS

In studies published between 1966 and 1996 on clipping of unruptured aneurysms, mortality was 2.6% and morbidity was 10.9%. In calculating the pros and cons of preventive surgery, these proportions should be taken into account.

The burden of caregiving in partners of long-term stroke survivors

BACKGROUND AND PURPOSE

Few data are available on the specific caregiving-related problems of stroke patients' caregivers and factors that influence the burden of these caregivers. The aim of this study was to describe the level and specific nature of the burden of caregiving as experienced by stroke patients' partners and to estimate the relative contribution of patient and partner characteristics to the presence of partners' burden.

METHODS

As part of a multicenter study on quality of care, burden of caregiving was assessed in 115 partners at 3 years after stroke. Explanatory factors of burden were studied in terms of (1) characteristics of patients (sociodemographic status, severity, type, and localization of stroke, disability, handicap, and unmet care demands) and (2) characteristics of partners (age, sex, disability, quality of life, loneliness, amount of care provided, and unmet care demands).

RESULTS

Partners of stroke patients perceived most caregiving burden in terms of feelings of heavy responsibility, uncertainty about patients' care needs, constant worries, restraints in social life, and feelings that patients rely on only their care. Multiple regression analysis revealed that a higher level of burden could partly be explained by patients' disability (R2 = 14%), but primarily by partners' characteristics in terms of emotional distress (R2 = 16%), loneliness (R2 = 6%), disability (R2 = 3%), amount of informal care provided (R2 = 2%), unmet demands for psychosocial care (R2 = 4%), and unmet demands for assistance in activities of daily living (R2 = 2%).

CONCLUSIONS

Higher levels of burden are primarily related to partners' emotional distress and less to the amount of care they provided, or to patients' characteristics. Sharing responsibilities, helping to clarify the patients' needs, and getting occasional relief of caregiving may be important in the support of caregivers.

[Cerebrovascular reactivity in non-insulin dependent diabetes mellitus (preliminary results)]

AIMS

Previously numerous investigators reported about impairment of cerebrovascular reserve capacity in Type I, diabetes mellitus. However, no similar data are available about patients suffering from Type II diabetes. The goal of the study was to assess cerebrovascular reserve in Type II diabetic patients.

PATIENTS AND METHODS

14 NIDDM patients and 20 healthy controls were studied. Middle cerebral artery mean blood flow velocity was measured at rest and during 20 minutes after i.v. administration of 1 g. acetazolamide. Velocities measured after acetazolamide were compared to resting values and were expressed as the percent increase of the mean velocity. Data obtained in diabetics and healthy persons were compared using Student's t-test. The correlation between age of the patients, diabetes duration, actual blood glucose-, insulin-, glycosylated hemoglobin-, urine microalbumin concentrations and resting blood flow velocity and cerebrovascular reserve capacity was assessed using linear regression analysis.

RESULTS

Resting cerebral blood flow velocities, cerebrovascular reactivity and reserve capacity did not differ from that of healthy controls. No correlation has been found between obtained laboratory parameters and resting cerebral blood flow velocities and cerebrovascular reserve capacity.

CONCLUSIONS

Vasodilatory ability of the cerebral arterioles in NIDDM-patients did not differ from that of healthy control persons. Further studies are needed to find out an accurate screening method for detection of cerebral microangiopathic changes in Type II diabetes mellitus.

The role of type III collagen in spontaneous cervical arterial dissections

A case-control study was carried out to investigate whether type III collagen deficiency plays a role in the pathogenesis of spontaneous cervical arterial dissections. In 16 patients with spontaneous cervical arterial dissections and in 41 healthy controls, protein analysis of type III collagen (ratio of type III/type I collagen) was performed. Furthermore, single-stranded conformation polymorphism/heteroduplex analysis was used to investigate the type III collagen gene in the 16 patients with spontaneous cervical dissections to detect mutations. The ratios of type III/type I collagen in the controls ranged from 5.5 to 19.8% (median, 10%). The ratios of type III/type I collagen in the patients with spontaneous cervical arterial dissections ranged from 3.2 to 17.9% (median, 9.3%). Two patients had a low ratio of type III/type I collagen (<5.5%). No abnormalities suggesting a mutation in the gene of type III collagen were demonstrated in any of the 16 patients. Our findings are in keeping with the hypothesis that a reduced production of type III collagen may contribute to the formation of spontaneous cervical arterial dissections in some patients. The absence of a responsible mutation indicates that the coding sequence of the type III collagen gene is not involved.

Ischemic stroke after surgical procedures: clinical features, neuroimaging, and risk factors

OBJECTIVE

To describe risk factors and explore mechanisms of ischemic strokes after general surgery.

BACKGROUND

Strokes follow general surgery in about 0.08% to 2.9% of cases. Patients with previous cerebrovascular disease, atrial fibrillation, hypertension, advanced age, or atherosclerosis were found to have an increased risk. Knowledge of factors involved may guide physicians in determining the overall risk of surgery.

METHODS

This case-control study was performed in a referral center. A total of 61 patients identified through a computerized database with ischemic strokes after surgical procedures-excluding heart, brain, vessels, or neck-between July 1986 and July 1996 were studied. Procedures included 11 urogenital, 16 gastrointestinal, 17 orthopedic, 12 pulmonary, and 5 other. A total of 122 randomly selected controls were matched for age, sex, procedure, and year of procedure. Main outcome measures included arterial territory, timing, risk factors, and perioperative events. Differences were expressed as adjusted odds ratios (AOR) with 95% confidence limits (CL), using multivariate conditional logistic analyses for matched case-control design.

RESULTS

Arterial territory included 37 middle cerebral artery, 11 posterior circulation, 7 borderzone, and 6 multiple. Median procedure to stroke interval was 2 days (range, 0 to 16); 10 patients had intraoperative strokes. Three major risk factors emerged: previous cerebrovascular disease (AOR 12.57, 95% CL 2.14/73.70), chronic obstructive pulmonary disease (COPD) (7.51, 1.87/30.12), and peripheral vascular disease (PVD) (5.35, 1.25/22.94). After adding stroke-related factors, PVD (14.70, 2.01/107.71) and COPD (10.04, 1.90/53.14) remained the strongest variables; blood pressure (1.05, 1.01/1.10) and urea (1.04, 1.01/1.07) contributed slightly. Hypotension did not contribute. Four patients (6.6%) and no controls had diffuse intravascular coagulation (p = 0.01). Four stroke patients had myocardial infarction (6.6% versus 0%; p = 0.01).

CONCLUSIONS

Ischemic strokes after general surgery most commonly occur after an asymptomatic interval. Previous cerebrovascular disease, COPD, and PVD greatly increase the risk. Hypotension rarely accounts for postoperative strokes. Major comorbidity of the patient at risk seems more important than complicating events during surgery.

[Assessment of cerebrovascular reactivity in patients with symptomatic and asymptomatic atherosclerotic carotid artery lesions]

AIMS

Strokes caused by hemodynamically significant internal carotid artery stenoses and occlusions are believed to be embolic or hemodynamic of origin. The aim of the study was to assess cerebral hemodynamic compromises of significant carotid artery stenosis of occlusion using vasodilatory testing (acetazolamide test) in asymptomatic and symptomatic patients.

PATIENTS AND METHODS

36 patients with unilateral, hemodynamically significant carotid stenosis were investigated using transcranial Doppler acetazolamide-test. There were 12 asymptomatic and 24 symptomatic patients. The middle cerebral artery mean blood flow velocity was measured at rest and after intravenous injection of 1 g acetazolamide. The absolute mean blood flow velocities and the cerebrovascular reactivity was compared at the stenotic and non-stenotic side. In a further analysis the mean velocities and the cerebrovascular reactivity values of the stenotic side were compared. Results of acetazolamide test performed on 28 healthy volunteers were used as control values.

RESULTS

There were no side-differences between the middle cerebral artery mean blood flow velocity and cerebrovascular reactivity values in the asymptomatic group. In the symptomatic group, however middle cerebral artery mean velocity and cerebrovascular reactivity after acetazolamide was significantly lower on the stenotic side, than on the non-stenotic one. Comparing the different groups non-stenotic sides did not differ to each other in their cerebral blood flow velocity and cerebrovascular reactivity. In the symptomatic patients, however, cerebral blood flow velocity and cerebrovascular reserve capacity after acetazolamide was lower, than that of the stenotic side of asymptomatic patients and controls.

CONCLUSIONS

The transcranial Doppler is a suitable method for detecting altered cerebral hemodynamics in significant carotid stenosis. Impaired cerebrovascular reactivity may refer to the impairment of cerebral autoregulatory mechanisms.