Clinical implications of benign multiple sclerosis: A 20-year population-based follow-up study

In 2001, we followed up all patients from the 1991 Olmsted County Multiple Sclerosis (MS) prevalence cohort. We found that the longer the duration of MS and the lower the disability, the more likely a patient is to remain stable and not progress. This is particularly powerful for patients with benign MS with Expanded Disability Status Scale score of 2 or lower for 10 years or longer who have a greater than 90% chance of remaining stable. This is important because these patients represent 17% of the entire prevalence cohort. These data should assist in the shared therapeutic decision-making process of whether to start immunomodulatory medications.

Cause Is the Main Predictor of Outcome in Patients with Pontine Hemorrhage

BACKGROUND

Pontine hemorrhages frequently lead to death or severe disability. Predictors of early mortality have been previously described but little is known about the factors influencing long-term disability.

OBJECTIVE

Determine clinical predictors of long-term outcome in a large hospital series of patients with acute pontine hemorrhage.

METHODS

Review of all patients with acute pontine hemorrhage admitted to a single tertiary center from 1990 to 2002 who underwent a diagnostic workup including brain magnetic resonance imaging (MRI). Long-term outcome was rated using the modified Rankin Scale (mRS) score at the time of the last follow-up. Odds ratios (ORs) for predictive factors were calculated using univariate and multivariable logistic regression analysis. Level of significance was established at p < 0.01.

RESULTS

We identified 44 consecutive patients with acute pontine hemorrhage. Twenty-four patients had primary hemorrhages (no cause other than hypertension). Arteriovenous or cavernous malformations were documented by brain MRI in 20 patients. Patients with primary hemorrhages had worse Glasgow Coma Scale sum scores (p = 0.01) and more unfavorable CT patterns (p = 0.005) at presentation. Eighteen percent of the patients died in the hospital. Mean follow-up among survivors was 20 months (range 3-144 months). Twenty-two percent of the patients remained severely disabled (mRS greater than 2) at 3 months and at the time of the last follow-up. All deaths occurred in patients with primary pontine hemorrhage. Poor outcome (death or severe disability) was more frequent in patients with primary hemorrhages when compared with patients harboring cavernous malformations (62 versus 5%; p < 0.01). Primary hemorrhage was the only independent predictor of poor outcome in multivariable regression analysis (OR 12; p = 0.029).

CONCLUSIONS

Cause is a main predictor of clinical and radiological severity at presentation and outcome in patients with pontine hemorrhage. The first episode of hemorrhage in patients with brainstem cavernous malformations is usually benign. Pontine hemorrhage associated with prior hypertension is much more devastating.

Mortality of large-artery complication (aortic aneurysm, aortic dissection, and/or large-artery stenosis) in patients with giant cell arteritis: A population-based study over 50 years

OBJECTIVE

To determine the mortality of giant cell arteritis (GCA) with large-artery complication compared with that of GCA without large-artery complication.

METHODS

An inception cohort of 168 residents of Olmsted County, Minnesota, in whom GCA was diagnosed between January 1, 1950, and December 31, 1999, was followed up. Mortality in patients with incident large-artery complication (aortic aneurysm, aortic dissection, and large-artery stenosis) was determined and compared with that in patients in whom large-artery complication did not develop.

RESULTS

No difference in survival was observed between the total group of patients with any type of large-artery complication and patients without large-artery complication or the general population. However, mortality was markedly increased in the 9 patients in whom thoracic aortic dissection developed (median survival 1.1 years [interquartile range 0.2-7.8 years]) compared with that in all other patients with GCA (P < 0.001). No difference in survival was observed between the group of patients with either aortic aneurysm and/or dissection (thoracic and/or abdominal aorta) and the group with GCA without large-artery complication. Survival of patients with GCA and large-artery stenosis was not different from that of patients with GCA without large-artery complication.

CONCLUSION

Thoracic aortic dissection in GCA is associated with markedly increased mortality. Overall, mortality in the whole group of patients with GCA with large-artery complication was similar to that in patients with GCA without large-artery complication.

Incidence and predictors of large-artery complication (aortic aneurysm, aortic dissection, and/or large-artery stenosis) in patients with giant cell arteritis: A population-based study over 50 years

OBJECTIVE

To determine the incidence and predictors of large-artery complication (aortic aneurysm, aortic dissection, and/or large-artery stenosis) in patients with giant cell arteritis (GCA).

METHODS

The cohort of all residents of Olmsted County, Minnesota, in whom GCA was diagnosed between January 1, 1950, and December 31, 1999, was followed up. The incidence of aortic aneurysm, aortic dissection, and large-artery stenosis was determined. Possible predictors and correlates of large-artery complication were assessed.

RESULTS

Forty-six incident cases of large-artery complication (representing 27% of the 168 patients in the cohort) were identified. These included 30 incident cases (18%) of aortic aneurysm and/or aortic dissection. Of these cases, 18 (11%) involved the thoracic aorta, with aortic dissection developing in 9 (5%). There were 21 incident cases (13%) of large-artery stenosis. Fifteen patients (9%) had incident cervical artery stenosis, and 6 (4%) had incident subclavian/axillary/brachial artery stenosis. One patient (0.6%) had incident iliac/femoral artery stenosis attributable to GCA. Hyperlipidemia and coronary artery disease were associated with aortic aneurysm and/or dissection (P < 0.05 for both). Cranial symptoms (headache, scalp tenderness, abnormal temporal arteries) were negatively associated with large-artery stenosis (hazard ratio [HR] 0.10 [95% confidence interval (95% CI) 0.03-0.35, P < 0.0005]), as was a higher erythrocyte sedimentation rate (HR 0.80 [95% CI 0.67-0.95, P < 0.05] per 10 mm/hour).

CONCLUSION

Large-artery complication is common in GCA. Increased awareness of large-artery complication in GCA, particularly early-occurring aortic dissection, may decrease associated mortality.

Evaluation of a novel propylene oxide—treated collagen material as a dural substitute

Object. The authors evaluated a new non—cross-linked, propylene oxide—treated, acellular collagen matrix for use as a dural substitute in rabbits. They then compared this material to a commonly used dural substitute as well as to native dura mater used during primary closure.

Methods. Forty-six rabbits were randomly assigned to eight groups of five or six rabbits each. These groups differed according to the type of closure material that was used during surgery (native dura, control dural substitute, or experimental dural substitute) and the duration of convalescence. At the end of the experiment, the tightness of the duraplasty was assessed in each live rabbit by continuous infusion of fluid into the cisterna magna until leakage was detected. The animals were killed and each specimen was sectioned and studied histologically. The authors found that the experimental dural substitute was safe in animals for this application, that it held sutures well, and that a watertight closure was usually achieved. There were fewer adhesions between the experimental material and neural tissue was less likely to adhere to the cranium than the control graft. Histological examination showed that the experimental material had slightly more spindle cells and vascularity than the control graft.

Conclusions. The experimental graft material has several features that make it an attractive candidate for use as a dural substitute.

Incidence and prevalence of multiple sclerosis in Olmsted County, Minnesota, 1985-2000

BACKGROUND

Epidemiologic data for multiple sclerosis (MS) in Olmsted County, MN, have been recorded for almost 100 years and have indicated that the increasing prevalence rate was likely due in part to an increasing incidence rate.

METHODS

All cases of MS diagnosed from 1985 to 2000 were identified using the centralized diagnostic index at the Mayo Clinic and the Rochester Epidemiology Program Project, a shared database of all medical practitioners in the county. Patients were required to have established residency at least 1 year prior to diagnosis of MS. Results were also age- and sex-adjusted to control for shifts in the population structure.

RESULTS

The raw prevalence of MS was determined to be 177 per 100,000 on December 1, 2000, and the raw incidence rate was 7.5 per 100,000 person-years at risk from 1985 to 2000.

CONCLUSIONS

After age and sex adjustment to a common population, these prevalence and incidence rates of MS appear to have been stable rather than increasing over the past 20 years.

Endothelial Nitric Oxide Synthase T-786C Single Nucleotide Polymorphism

Background and Purpose— Anecdotal evidence exists for at least 2 subpopulations of intracranial saccular aneurysms, namely, those that may form rapidly and rupture when small versus those that enlarge slowly and may rupture particularly when ≥10 mm in diameter. We sought to determine whether the endothelial nitric oxide synthase (eNOS) T-786C single nucleotide polymorphism (SNP), implicated in cardiovascular disease susceptibility, could facilitate differentiation between small (≤5 mm) versus large (≥10 mm) ruptured aneurysms.

Methods— In accordance with institutional guidelines, clinical data were recorded prospectively and genomic DNA was isolated from blood samples obtained from 52 aneurysmal subarachnoid hemorrhage (SAH) patients (cases) and 90 randomly selected controls. Samples were assayed for eNOS gene promoter T-786C SNP with the use of gene microarray technology. Statistical analyses included multiple logistic regression.

Results— Although there was no difference in genotype distributions between cases and controls, all 13 patients with large aneurysms were ( T / C ) heterozygous for the polymorphism, while 9 of 22 patients (41%) with small aneurysms were ( T / T or C / C ) homozygous ( P =0.01). The mean (±SD) ruptured aneurysm diameter among all heterozygotes (8.5±5.2 mm) was significantly greater than that for C / C (6.0±2.3 mm) or T / T (4.7±1.8 mm) homozygotes ( P =0.04). With the use of multivariate analysis, heterozygosity remained significantly associated with aneurysm size ≥10 mm ( P =0.03).

Conclusions— The eNOS T-786C SNP distinguishes genetically between small and large ruptured aneurysms. Although not predictive of SAH in the population at large, our data suggest that among persons with known intracranial aneurysms, eNOS T-786C genotype may be a factor influencing the size at which an aneurysm ruptures, a finding that should be taken into consideration along with other anatomic features of the aneurysm.

Interleukin-1β and adverse effects on cerebral blood flow during long-term global hypoperfusion

Object. The effects of interleukin (IL)-1β on the cerebral vasculature are complex and incompletely understood. Many pathophysiological states in which inflammatory cascades have been implicated also have varying degrees of cerebral hypoperfusion. The purpose of this investigation was to examine the long-term effects of this proinflammatory cytokine and its antagonist on cerebral blood flow (CBF) following global cerebral hypoperfusion.

Methods. Sprague—Dawley rats were randomly assigned to 12 groups and given continuous intracerebroventricular (ICV) infusions of IL-1β, the IL-1 receptor antagonist (IL-1ra), or saline vehicle (control). Global cerebral hypoperfusion was produced by occlusion of both carotid arteries and one vertebral artery. Cerebral blood flow was measured at baseline and again after initiation of the infusions by performing a 133Xe clearance study.

Prolonged ICV administration of IL-1β resulted in a significant decrease in CBF compared with that in controls. Prolonged administration of the antagonist IL-1ra resulted in significant increases in CBF compared with that in both IL-1β—treated animals and controls.

Conclusions. This experiment demonstrates that long-term treatment with the proinflammatory cytokine IL-1β adversely affects CBF.

Emergency intubation for respiratory failure in Guillain-Barré syndrome

BACKGROUND

The consequences of emergency intubation in Guillain-Barré syndrome are not known.

OBJECTIVE

To review data from patients admitted to the intensive care unit with recent diagnosis of Guillain-Barré syndrome and intubation for respiratory failure.

DESIGN, SETTING, AND PATIENTS

The database of patients with Guillain-Barré syndrome admitted to the intensive care units during the past 2 decades was reviewed. Emergency intubation was defined as need for ventilation in a patient with sudden dyspnea, cyanosis, or respiratory arrest. Outcome and pulmonary morbidity were assessed by comparing these patients with patients intubated electively.

RESULTS

Six patients were intubated for acute respiratory distress and 1 patient for respiratory arrest. Thirty-six patients were intubated electively. Prolonged weaning was twice as common in the emergent group as in the elective group; a larger sample size might have demonstrated statistical significance. One patient with respiratory arrest developed marked anoxic encephalopathy; in all others, no differences were found in mortality, pulmonary morbidity, or duration of ventilatory assistance. None of the emergency intubations occurred in the last 15 years of the study.

CONCLUSIONS

Emergency intubation in Guillain-Barré syndrome is uncommon but, when associated with respiratory arrest, can lead to anoxic encephalopathy. Duration of ventilator use and pulmonary morbidity are not increased in these patients.

Selective peripheral denervation for the treatment of intractable spasmodic torticollis: experience with 168 patients at the Mayo Clinic

OBJECT

Selective peripheral denervation is currently the primary surgical treatment for intractable cervical dystonia. The authors assessed preoperative factors to determine which, if any, correlated with outcomes in patients with torticollis who had undergone this procedure.

METHODS

The records of 168 consecutive patients who had undergone selective peripheral denervation for cervical dystonia between 1988 and 1996 at the Mayo Clinic were reviewed. There were 89 women (53%) and 79 men (47%) with a mean age of 53.4 years. Selection of muscles for denervation was based on the patient's clinical presentation and electromyography mapping results. The most common torticollis vectors were rotational in 141 patients (84%) and laterocollis in 59 (35%). Seventy patients (42%) presented with combined vectors. The technique used to remedy both conditions involved denervation of the ipsilateral posterior cervical paraspinal and splenius capitis muscles. Denervation of the sternocleidomastoid muscle was performed on the contralateral side for rotational torticollis and on the ipsilateral side for laterocollis. A rigorous physical therapy program followed surgery. At the 3-month postoperative evaluation, 125 patients (77%) of the 162 who were available for follow up had moderate to excellent improvement in their head position, and pain was moderately to markedly improved in 131 patients (81%). The long-term follow up lasted a mean of 3.4 years and was undertaken in 130 patients. The original level of moderate to excellent improvement in head position and pain was retained in at least 71 patients (70%). Outcome was not predicted by preoperative head position, severity of abnormal posture of head, symptom duration, presence of tremor or phasic dystonic movements, or failure to respond to botulinum toxin treatment. Five patients recovered from postoperative complications including one myocardial infarction, one pulmonary embolism, and three respiratory failures. Three patients suffered from persistent C-2 distribution dysesthesias and three from slight shoulder weakness; one had a wound infection, and one died of respiratory arrest.

CONCLUSIONS

Selective peripheral denervation is an effective method of achieving lasting improvement of dystonia in most patients with intractable torticollis.

Acute postoperative seizures after frontal lobe cortical resection for intractable partial epilepsy

PURPOSE

To evaluate the incidence and prognostic importance of acute postoperative seizures (APOSs) occurring in the first week after a focal corticectomy in patients with partial epilepsy of frontal lobe origin.

METHODS

We retrospectively evaluated 65 patients who underwent a frontal lobe cortical resection for intractable partial epilepsy between April 1987 and December 2000. All patients were followed up for a minimum of 1 year after surgery.

RESULTS

APOSs occurred in 17 (26%) patients. None of the following factors was shown to be significantly associated with the occurrence of APOSs: gender, duration of epilepsy, etiology for seizure disorder, use of subdural or depth electrodes, surgical pathology, or postoperative risk factor for seizures. Patients with APOSs were older at seizure onset and at the time of surgery (p = 0.003 and p = 0.05, respectively). At last follow-up, patients who had APOSs had a seizure-free outcome similar to that of individuals without APOSs (47.1% vs. 50.0%; p = 0.77). Patients with APOSs appeared less likely to have a favorable outcome [i.e., fewer than three seizures per year and >95% decrease in seizure activity (58.8 vs. 70.8%; p = 0.35)]. This result may not have reached statistical significance because of the sample size. No evidence suggested that precipitating factors or the timing of APOSs was an important prognostic factor.

CONCLUSIONS

The presence of APOSs after frontal lobe surgery for intractable epilepsy does not preclude a significant reduction in seizure tendency. These findings may be useful in counseling patients who undergo surgical treatment for frontal lobe epilepsy.

Pulmonary Complications of Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

Pulmonary complications challenge the medical management of patients who have sustained aneurysmal subarachnoid hemorrhage (SAH). We assessed the frequency and types of pulmonary complications after aneurysmal SAH and analyzed the impact of pulmonary complications on patient outcome.

METHODS

We reviewed the records of all patients with acute SAH treated at our institution between 1990 and 1997. Three hundred five consecutive patients with an aneurysmal hemorrhage source documented by angiography and treated within 7 days of ictus were analyzed. Outcomes at longest follow-up (mean, 16 mo) were measured by use of the Glasgow Outcome Scale.

RESULTS

Pulmonary complications were documented in 66 patients (22%). The pulmonary complications were nosocomial pneumonia in 26 patients (9%), congestive heart failure in 23 (8%), aspiration pneumonia in 17 (6%), neurogenic pulmonary edema in 5 (2%), pulmonary embolus in 2 (&lt;1%), and other pulmonary disorders in 4 (1%); 11 patients had two pulmonary complications. The incidence of symptomatic vasospasm was greater in patients with pulmonary complications (63%) than in patients without pulmonary complications (31%) (P= 0.001), and this association was independent of age and clinical grade at admission (odds ratio, 3.68; P&lt; 0.001). Overall clinical outcomes were worse in patients with pulmonary complications (mean Glasgow Outcome Scale score, 3.3) than in patients without pulmonary complications (mean Glasgow Outcome Scale score, 4.0; P= 0.0001), but pulmonary complications were not an independent predictor of worse outcome when adjusted for age and clinical grade at admission (odds ratio, 1.38; P= 0.315).

CONCLUSION

Patients who experience pulmonary complications after aneurysmal SAH have a higher incidence of symptomatic vasospasm than do patients without pulmonary complications. This most likely reflects both the failure to maintain aggressive hypervolemic and hyperdynamic therapy in patients with pulmonary compromise and the possible precipitation of congestive heart failure by hypervolemic therapy in patients with preexisting delayed ischemic neurological deficit. Although patients with pulmonary complications have worse overall clinical outcomes than do patients without pulmonary complications, this is attributable to older age and worse clinical grades at admission.

Complex regional pain syndrome type I: incidence and prevalence in Olmsted county, a population-based study

The objective of this study is to undertake a population based study on the incidence, prevalence, natural history, and response to treatment of complex regional pain syndrome (CRPS). All Mayo Clinic and Olmsted Medical Group medical records with codes for reflex sympathetic dystrophy (RSD), CRPS, and compatible diagnoses in the period 1989-1999 were reviewed as part of the Rochester Epidemiology Project. We used IASP criteria for CRPS. The study population was in the Olmsted County, Minnesota (1990 population, 106,470). The main outcome measures were CRPS I incidence, prevalence, and outcome. Seventy-four cases of CRPS I were identified, resulting in an incidence rate of 5.46 per 100,000 person years at risk, and a period prevalence of 20.57 per 100,000. Female:male ratio was 4:1, with a median age of 46 years at onset. Upper limb was affected twice as commonly as lower limb. All cases reported an antecedent event and fracture was the most common trigger (46%). Excellent concordance was found between symptoms and signs and vasomotor symptoms were the most commonly present. Three phase bone scan and autonomic testing diagnosed the condition in >80% of cases. Seventy-four percent of patients underwent resolution, often spontaneously. CRPS I is of low prevalence, more commonly affects women than men, the upper more than the lower extremity, and three out of four cases undergo resolution. These results suggest that invasive treatment of CRPS may not be warranted in the majority of cases.

Pulmonary complications of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Pulmonary complications challenge the medical management of patients who have sustained aneurysmal subarachnoid hemorrhage (SAH). We assessed the frequency and types of pulmonary complications after aneurysmal SAH and analyzed the impact of pulmonary complications on patient outcome.

METHODS

We reviewed the records of all patients with acute SAH treated at our institution between 1990 and 1997. Three hundred five consecutive patients with an aneurysmal hemorrhage source documented by angiography and treated within 7 days of ictus were analyzed. Outcomes at longest follow-up (mean, 16 mo) were measured by use of the Glasgow Outcome Scale.

RESULTS

Pulmonary complications were documented in 66 patients (22%). The pulmonary complications were nosocomial pneumonia in 26 patients (9%), congestive heart failure in 23 (8%), aspiration pneumonia in 17 (6%), neurogenic pulmonary edema in 5 (2%), pulmonary embolus in 2 (<1%), and other pulmonary disorders in 4 (1%); 11 patients had two pulmonary complications. The incidence of symptomatic vasospasm was greater in patients with pulmonary complications (63%) than in patients without pulmonary complications (31%) (P = 0.001), and this association was independent of age and clinical grade at admission (odds ratio, 3.68; P < 0.001). Overall clinical outcomes were worse in patients with pulmonary complications (mean Glasgow Outcome Scale score, 3.3) than in patients without pulmonary complications (mean Glasgow Outcome Scale score, 4.0; P = 0.0001), but pulmonary complications were not an independent predictor of worse outcome when adjusted for age and clinical grade at admission (odds ratio, 1.38; P = 0.315).

CONCLUSION

Patients who experience pulmonary complications after aneurysmal SAH have a higher incidence of symptomatic vasospasm than do patients without pulmonary complications. This most likely reflects both the failure to maintain aggressive hypervolemic and hyperdynamic therapy in patients with pulmonary compromise and the possible precipitation of congestive heart failure by hypervolemic therapy in patients with preexisting delayed ischemic neurological deficit. Although patients with pulmonary complications have worse overall clinical outcomes than do patients without pulmonary complications, this is attributable to older age and worse clinical grades at admission.

Symptomatic vasospasm and outcomes following aneurysmal subarachnoid hemorrhage: a comparison between surgical repair and endovascular coil occlusion

OBJECT

The authors studied patients with aneurysmal subarachnoid hemorrhage (SAH) to determine whether the incidence of symptomatic vasospasm or overall clinical outcomes differed between patients treated with craniotomy and clip application and those treated by endovascular coil occlusion.

METHODS

The authors reviewed 415 consecutive patients with aneurysmal SAH who had been treated with either craniotomy and clip application or endovascular coil occlusion at a single institution between 1990 and 2000. Three hundred thirty-nine patients underwent surgical clip application procedures, whereas 76 patients underwent endovascular coil occlusion. Symptomatic vasospasm occurred in 39% of patients treated with clip application, 30% of patients treated with endovascular coil occlusion, and 37% of patients overall. Compared with patients treated with clip application, patients treated with endovascular coil occlusion were more likely to suffer acute hydrocephalus (50 compared with 34%, p = 0.008) and were more likely to harbor aneurysms in the posterior circulation (53 compared with 20%, p < 0.001). Logistic regression models controlling for patient age, admission World Federation of Neurosurgical Societies (WFNS) grade, acute hydrocephalus, aneurysm location, and day of treatment revealed that, among patients with an admission WFNS grade of I to III, endovascular coil occlusion carried a lower risk of symptomatic vasospasm (odds ratio [OR] 0.34, 95% confidence interval [CI] 0.14-0.8) and death or permanent neurological deficit due to vasospasm (OR 0.28, 95% CI 0.08-1) compared with craniotomy and clip application. Similar models revealed no difference in the likelihood of a Glasgow Outcome Scale score of 3 or less at the longest follow-up review (median 6 months) between treatment groups (OR 0.58, 95% CI 0.28-1.21).

CONCLUSIONS

Patients with better clinical grades (WFNS Grades I-III) at hospital admission were less likely to suffer symptomatic vasospasm when treated by endovascular coil occlusion, compared with craniotomy and clip application. Nevertheless, there was no significant difference in overall outcome at the longest follow-up examination between the two treatment groups.

The morbidity of Guillain-Barré syndrome admitted to the intensive care unit

Patients with severe forms of Guillain-Barré syndrome (GBS) require intensive care. Specific treatment, catheterization, and devices may increase morbidity in the intensive care unit (ICU). To understand the spectrum of morbidity associated with ICU care, the authors studied 114 patients with GBS. Major morbidity occurred in 60% of patients. Complications were uncommon if ICU stay was less than 3 weeks. Respiratory complications such as pneumonia and tracheobronchitis occurred in half of the patients and were linked to mechanical ventilation. Systemic infection occurred in one-fifth of patients and was more frequent with increasing duration of ICU admission. Direct complications of treatment and invasive procedures occurred infrequently. Life-threatening complications such as gastrointestinal bleeding and pulmonary embolism were very uncommon. Pulmonary morbidity predominates in patients with severe GBS admitted to the ICU. Attention to management of mechanical ventilation and weaning is important to minimize this complication of GBS. Other causes of morbidity in a tertiary center ICU are uncommon.

Preoperative ventriculostomy and rebleeding after aneurysmal subarachnoid hemorrhage

OBJECT

Despite the widespread use of ventriculostomy in the treatment of acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH), there is no consensus regarding the risk of rebleeding associated with ventriculostomy before aneurysm repair. This present study was conducted to assess the risk of rebleeding after preoperative ventriculostomy in patients with aneurysmal SAH.

METHODS

The authors reviewed the records of all patients with acute SAH who were treated at a single institution between 1990 and 1997. Thus, the records of 304 consecutive patients in whom an aneurysmal SAH source was documented on angiographic studies and who had presented to the authors' institution within 7 days of ictus were analyzed. Re-bleeding was confirmed by evidence of recurrent hemorrhage on computerized tomography scans in all cases. Forty-five patients underwent ventriculostomy for acute hydrocephalus after aneurysmal SAH at least 24 hours before aneurysm repair. Ventriculostomy was performed within 24 hours of SAH in 38 patients, within 24 to 48 hours in three patients, and more than 48 hours after SAH in four patients. The mean time interval between SAH and surgery in patients who did not undergo ventriculostomy was no different from the mean interval between ventriculostomy and surgery in patients who underwent preoperative ventriculostomy (3.6 compared with 3.8 days, p = 0.81). Fourteen (5.4%) of the 259 patients who did not undergo ventriculostomy suffered preoperative aneurysm rebleeding, whereas two (4.4%) of the 45 patients who underwent preoperative ventriculostomy had aneurysm rebleeding.

CONCLUSIONS

No evidence was found that preoperative ventriculostomy performed after aneurysmal SAH is associated with an increased risk of aneurysm rebleeding when early aneurysm surgery is performed.

Outcome of congestive heart failure in elderly persons: influence of left ventricular systolic function. The Cardiovascular Health Study

BACKGROUND

Most persons with congestive heart failure are elderly, and many elderly persons with congestive heart failure have normal left ventricular systolic function.

OBJECTIVE

To evaluate the relationship between left ventricular systolic function and outcome of congestive heart failure in elderly persons.

DESIGN

Population-based longitudinal study of coronary heart disease and stroke.

SETTING

Four U.S. sites: Forsyth County, North Carolina; Sacramento County, California; Allegheny County, Pennsylvania; and Washington County, Maryland.

PARTICIPANTS

5888 persons who were at least 65 years of age and were recruited from the community.

MEASUREMENTS

Total mortality and cardiovascular morbidity and mortality.

RESULTS

Of 5532 participants, 269 (4.9%) had congestive heart failure. Among these, left ventricular function was normal in 63%, borderline decreased in 15%, and overtly impaired in 22%. The mortality rate was 25 deaths per 1000 person-years in the reference group (no congestive heart failure and normal left ventricular function at baseline); 154 deaths per 1000 person-years in participants with congestive heart failure and impaired left ventricular systolic function; 87 and 115 deaths per 1000 person-years in participants with congestive heart failure and normal or borderline systolic function, respectively; and 89 deaths per 1000 person-years in persons with impaired left ventricular function but no congestive heart failure. Although the risk for death from congestive heart failure was lower in persons with normal systolic function than in those with impaired function, more deaths were associated with normal systolic function because more persons with heart failure fall into this category.

CONCLUSIONS

Community-dwelling elderly persons, especially those with impaired left ventricular function, have a substantial risk for death from congestive heart failure. However, more deaths occur from heart failure in persons with normal systolic function because left ventricular function is more often normal than impaired in elderly persons with heart failure.

Incidence of seizures in patients with multiple sclerosis: a population-based study

OBJECTIVE

To determine whether multiple sclerosis (MS) is associated with occurrence of seizure activity.

PATIENTS AND METHODS

The medical records of all incidence patients with MS in Olmsted County, Minnesota, from 1935 to 1991 were reviewed. The incidence of seizures was calculated by using 3 methods: including only seizures that occurred after definite diagnosis of MS, including all seizures occurring after onset of the first symptoms of MS, and including any seizures regardless of the time of onset relative to MS. These incidences were age-adjusted to the 1970 US population and then compared with the age-adjusted incidence rate of seizures in the general population of Olmsted County.

RESULTS

The age-adjusted incidence of seizures among MS patients was not significantly higher than the age-adjusted incidence of seizures in the general population of Olmsted County. The age-adjusted incidence of first unprovoked seizures in Rochester, Minn, was 61 per 100,000 person-years. In patients with the definite diagnosis of MS, the age-adjusted Incidence was calculated at 61 per 100,000 person-years (95% confidence interval [CI], 7-114). In the group with seizures after onset of symptoms, the age-adjusted incidence rate was 80 per 100,000 person-years (95% CI, 24-135). In the group with seizures at any time in their life, the age-adjusted incidence rate was 82 per 100,000 person-years (95% CI, 41-158).

CONCLUSION

The present study does not suggest that occurrence of seizures is more common in MS patients than in the general population.

Volumetric quantification of Fisher Grade 3 aneurysmal subarachnoid hemorrhage: a novel method to predict symptomatic vasospasm on admission computerized tomography scans

OBJECT

Predicting which patients with aneurysmal subarachnoid hemorrhage (SAH) will develop delayed ischemic neurological deficit (DIND) due to vasospasm remains subjective and unreliable. The authors analyzed the utility of a novel software-based technique to quantify hemorrhage volume in patients with Fisher Grade 3 aneurysmal SAH.

METHODS

Patients with aneurysmal SAH in whom a computerized tomography (CT) scan was performed within 72 hours of ictus and demonstrated Fisher Grade 3 SAH were analyzed. Severe DIND was defined as new onset complete focal deficit or coma. Moderate DIND was defined as new onset partial focal deficit or impaired consciousness without coma. Fifteen consecutive patients with severe DIND, 13 consecutive patients with moderate DIND, and 12 consecutive patients without DIND were analyzed. Software-based volumetric quantification was performed on digitized admission CT scans by a single examiner blinded to clinical information. There was no significant difference in age, sex, admission Hunt and Hess grade, or time to admission CT scan among the three groups (none, moderate, or severe DIND). Patients with severe DIND had a significantly higher cisternal volume of hemorrhage (median 30.5 cm3) than patients with moderate DIND (median 12.4 cm3) and patients without DIND (median 10.3 cm3; p < 0.001). Intraparenchymal hemorrhage and intraventricular hemorrhage were not associated with DIND. All 13 patients with cisternal volumes greater than 20 cm3 developed DIND, compared with 15 of 27 patients with volumes less than 20 cm3 (p = 0.004).

CONCLUSIONS

The authors developed a simple and potentially widely applicable method to quantify SAH on CT scans. A greater volume of cisternal hemorrhage on an admission CT scan in patients with Fisher Grade 3 aneurysmal SAH is highly associated with DIND. A threshold of cisternal hemorrhage volume (> 20 cm3) may exist above which patients are very likely to develop DIND. Prospective application of software-based volumetric quantification of cisternal SAH may predict which patients will develop DIND.

Use of cerebrospinal fluid flow rates measured by phase-contrast MR to predict outcome of ventriculoperitoneal shunting for idiopathic normal-pressure hydrocephalus

OBJECTIVE

To determine whether favorable clinical response and magnitude of improvement are associated with increased aqueductal cerebrospinal fluid (CSF) flow rates in patients who undergo ventriculoperitoneal shunting (VPS) for idiopathic normal-pressure hydrocephalus (NPH).

PATIENTS AND METHODS

Between January 1995 and June 2000, 49 patients (14 men and 35 women; mean age, 72.9 years; range, 54-88 years) underwent magnetic resonance quantification of aqueductal CSF flow followed by VPS for presumed idiopathic NPH at the Mayo Clinic, Rochester, Minn. Logistic regression models for the odds of any improvement in score as a function of aqueductal CSF flow and separate models for any improvement in gait, incontinence, cognition, and total score were constructed.

RESULTS

Forty-two patients (86%) had improvement in gait at postoperative follow-up (mean, 10 months). Of the 32 patients with incontinence, 27 (69%) improved. Of the 36 patients with cognitive impairment, 16 (44%) improved. In univariate and fully adjusted models, increased CSF flow through the aqueduct was not significantly associated with improvement or the magnitude of improvement in gait, cognition, or incontinence. Thirty-six patients underwent high-volume lumbar puncture preoperatively, of whom 5 (14%) had no response. The aqueductal CSF flow rates of these 5 patients were significantly higher than those of the patients who improved after lumbar puncture. Postoperative complications occurred in 15 patients. The aqueductal CSF flow rates in these 15 patients were not significantly different from those of patients who experienced no complications.

CONCLUSION

Among patients who underwent VPS for the treatment of NPH, measurement of CSF flow through the cerebral aqueduct did not reliably predict which patients would improve after shunting or the magnitude of improvement.

Regression-based variable clustering for data reduction

In many studies it is of interest to cluster states, counties or other small regions in order to obtain improved estimates of disease rates or other summary measures, and a more parsimonious representation of the country as a whole. This may be the case if there are too many to summarize concisely, and/or many regions with a small number of cases. By merging the regions into larger geographic areas, we obtain more cases within each area (and hence lower standard errors for parameter estimates), as well as fewer areas to summarize in terms of disease rates. The resulting clusters should be such that regions within the same cluster are similar in terms of their disease rates. In this paper we present a clustering algorithm which uses data at the subject-specific level in order to cluster the original regions into a reduced set of larger areas. The proposed clustering algorithm expresses the clustering goals in terms of a regression framework. This formulation of the problem allows the regions to be clustered in terms of their association with the response, and confounding variables measured at the subject-specific level may be easily incorporated during the clustering process. Additionally, this framework allows estimation and testing of the association between the areas and the response. The statistical properties and performance of the algorithm were evaluated via simulation studies, and the results are promising. Additional simulations illustrate the importance of controlling for confounding variables during the clustering process, rather than after the clusters are determined. The algorithm is illustrated with data from the Cardiovascular Health Study. Although developed with a specific application in mind, the method is applicable to a wide range of problems.

Measurement of cerebrospinal fluid flow at the cerebral aqueduct by use of phase-contrast magnetic resonance imaging: technique validation and utility in diagnosing idiopathic normal pressure hydrocephalus

OBJECTIVE

We analyzed the reliability of a protocol for measuring quantitative cerebrospinal fluid (CSF) flow at the cerebral aqueduct and established the range of CSF flows in normal elderly patients, patients with Alzheimer's and other forms of dementia, and patients with idiopathic normal pressure hydrocephalus (NPH).

METHODS

A constant flow phantom was used to establish the accuracy of the CSF flow measurement. The clinical variability of the measurement was estimated by calculating the standard deviations and coefficients of variation of intra- and interobserver and intertrial data sets derived from three normal volunteers. A total of 236 patients were studied, including 47 normal elderly patients, 115 patients with cognitive impairment (9 with mild cognitive impairment, 46 with Alzheimer's disease, and 60 with other cognitive impairment), 31 patients in whom NPH was suspected but ultimately excluded, and 43 patients with a final clinical diagnosis of NPH.

RESULTS

The intraobserver, interobserver, and intertrial measurement variations of 6.4, 5.4, and 8.8%, respectively, were substantially smaller than the wide variation observed among subjects. There was no statistically significant difference in flow between normal elderly patients and patients with cognitive impairment (P = 0.91). When these populations were pooled, the average flow was 8.47 ml/min (standard deviation, 4.23; range, 0.9-18.5 ml/min). The average flow rate in patients with a final clinical diagnosis of NPH was 27.4 ml/min (standard deviation, 15.3; range, 3.13-62.2 ml/min). This was significantly higher than the flow rate in each of the other three groups (all, P < 0.001).

CONCLUSION

CSF flow measurements of less than 18 ml/min with a sinusoidal flow pattern are normal. CSF flow of greater than 18 ml/min suggests idiopathic NPH.