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J Pile-Spellman

Publications and source records attributed to J Pile-Spellman.

At least 19 recordsLinked to original sources
PubMed2006

Intracerebral hemorrhage in pregnancy: frequency, risk factors, and outcome.

OBJECTIVE: To describe the frequency, risk factors, and outcome of intracerebral hemorrhage (ICH) in pregnancy and the postpartum period using a large database of US inpatient hospitalizations. METHODS: The authors obtained data from an administrative dataset, the Nationwide Inpatient Sample, which includes approximately 20% of all discharges from non-Federal hospitals, for the years 1993 through 2002. Women aged 15 to 44 years with a diagnosis of ICH were selected from the database for analysis, and within this group patients coded as pregnant or postpartum were identified. Using US Census data, estimates were made of the rates of ICH in pregnant/postpartum and non-pregnant women. Rates of various comorbidities in patients with pregnancy-related ICH were compared to the rates found in the general population of delivering patients using multivariate logistic regression to identify independent risk factors for pregnancy-related ICH. RESULTS: The authors identified 423 patients with pregnancy-related ICH, which corresponded to 6.1 pregnancy-related ICH per 100,000 deliveries and 7.1 pregnancy-related ICH per 100,000 at-risk person-years (compared to 5.0 per 100,000 person-years for non-pregnant women in the age range considered). The increased risk of ICH associated with pregnancy was largely attributable to ICH occurring in the postpartum period. The in-hospital mortality rate for pregnancy-related ICH was 20.3%. ICH accounted for 7.1% of all pregnancy-related mortality recorded in this database. Significant independent risk factors for pregnancy-related ICH included advanced maternal age (OR 2.11, 95% CI 1.69 to 2.64), African American race (OR 1.83, 95% CI 1.39 to 2.41), preexisting hypertension (OR 2.61, 95% CI 1.34 to 5.07), gestational hypertension (OR 2.41, 95% CI 1.62 to 3.59), preeclampsia/eclampsia (OR 10.39, 95% CI 8.32 to 12.98), preexisting hypertension with superimposed preeclampsia/eclampsia (OR 9.23, 95% CI 5.26 to 16.19), coagulopathy (OR 20.66, 95% CI 13.67 to 31.23), and tobacco abuse (OR 1.95, 95% CI 1.11 to 3.42). CONCLUSION: Intracerebral hemorrhage (ICH) accounts for a substantial portion of pregnancy-related mortality. The risk of ICH associated with pregnancy is greatest in the postpartum period. Advanced maternal age, African American race, hypertensive diseases, coagulopathy, and tobacco abuse were all independent risk factors for pregnancy-related ICH.

Adolescent↗
PubMed2006

Predictors of hemorrhage in patients with untreated brain arteriovenous malformation.

BACKGROUND: Intracranial hemorrhage is a serious possible complication in patients with brain arteriovenous malformation (AVM). Several morphologic factors associated with hemorrhagic AVM presentation have been established, but their relevance for the risk of subsequent AVM hemorrhage remains unclear. METHODS: The authors analyzed follow-up data on 622 consecutive patients from the prospective Columbia AVM database, limited to the period between initial AVM diagnosis and the start of treatment (i.e., any endovascular, surgical, or radiation therapy). Univariate and multivariate logistic regression and Cox proportional hazard models were applied to analyze the effect of patient age, gender, AVM size, anatomic location, venous drainage pattern, and associated arterial aneurysms on the risk of intracranial hemorrhage at initial presentation and during follow-up. RESULTS: The mean pretreatment follow-up was 829 days (median: 102 days), during which 39 (6%) patients experienced AVM hemorrhage. Increasing age (hazard ratio [HR] 1.05, 95% CI 1.03 to 1.08), initial hemorrhagic AVM presentation (HR 5.38, 95% CI 2.64 to 10.96), deep brain location (HR 3.25, 95% CI 1.30 to 8.16), and exclusive deep venous drainage (HR 3.25, 95% CI 1.01 to 5.67) were independent predictors of subsequent hemorrhage. Annual hemorrhage rates on follow-up ranged from 0.9% for patients without hemorrhagic AVM presentation, deep AVM location, or deep venous drainage to as high as 34.4% for those harboring all three risk factors. CONCLUSIONS: Hemorrhagic arteriovenous malformation (AVM) presentation, increasing age, deep brain location, and exclusive deep venous drainage appear to be independent predictors for AVM hemorrhage during natural history follow-up. The risk of spontaneous hemorrhage may be low in AVMs without these risk factors.

Adolescent↗
PubMed2004

Association of infratentorial brain arteriovenous malformations with hemorrhage at initial presentation.

BACKGROUND AND PURPOSE: The goal of this study was to analyze the association of hemorrhagic presentation with infratentorial brain arteriovenous malformations (AVMs). METHODS: The 623 consecutive, prospectively enrolled patients from the Columbia AVM Databank were analyzed in a cross-sectional study. Clinical presentation (diagnostic event) was categorized as intracranial hemorrhage or nonhemorrhagic presentation. From brain imaging and cerebral angiography, AVM location was classified as either infratentorial or supratentorial. Univariate and multivariate statistical models were applied to test the effect of age, sex, AVM size and location, venous drainage pattern, and associated (ie, feeding artery or intranidal) arterial aneurysms on the likelihood of hemorrhage at initial AVM presentation. RESULTS: Of the 623 patients, 72 (12%) had an infratentorial and 551 (88%) had a supratentorial AVM. Intracranial hemorrhage was the presenting symptom in 283 patients (45%), and infratentorial AVM location was significantly more frequent (18%) among patients who bled initially (6%; odds ratio [OR], 3.60; 95% confidence interval [CI], 2.09 to 6.20). This difference remained significant (OR, 1.99; 95% CI, 1.07 to 3.69) in the multivariate logistic regression model controlling for age, sex, AVM size, deep venous drainage, and associated arterial aneurysms. In the same model, the effect of other established determinants for AVM hemorrhage--ie, AVM size (in 1-mm increments; OR, 0.95; 95% CI, 0.94 to 0.96), deep venous drainage (OR, 3.09; 95% CI, 1.87 to 5.12), and associated aneurysms (OR, 2.78; 95% CI, 1.76 to 4.40)--remained significant. CONCLUSIONS: Our findings suggest that infratentorial AVM location is independently associated with hemorrhagic AVM presentation.

Adult↗
PubMed2003

Urgent endovascular revascularization for symptomatic intracranial atherosclerotic stenosis.

BACKGROUND: Endovascular revascularization for intracranial atherosclerotic stenoses is being increasingly performed at major medical centers and has been reported to be technically feasible and safe. The authors report their experience with patients who underwent such a procedure for impending stroke and neurologic instability. METHOD: All 18 patients (21 intracranial lesions) treated between 1997 and 2002 at the authors' institution with endovascular revascularization were retrospectively reviewed. Each patient had failed maximal medical therapy and was thought to be at high risk for an imminent stroke. RESULTS: Endovascular revascularization was performed on eight distal internal carotid artery lesions, six middle cerebral artery lesions, four intracranial vertebral artery lesions, and three basilar artery lesions. Recanalization was complete in 5 arteries (Thrombolysis in Myocardial Infarction [TIMI] Grade III), partial in 14 arteries (TIMI Grade II), and complete occlusion (TIMI 0) developed in 1 artery. In a patient with a tight basilar stenosis, no angioplasty could be performed because of the inability to cross the stenosis with the guidewire. Major periprocedural complications occurred in 9 (50%) patients: intracranial hemorrhage in 3 (17%), disabling ischemic stroke in 2 (11%), and major extracranial hemorrhage in 4 (22%). Three patients died: one from intracerebral hemorrhage and two from cardiorespiratory failure. CONCLUSIONS: Endovascular revascularization of intracranial vessels is technically feasible and may be performed successfully. However, periprocedural complication and fatality rates in neurologically unstable patients are high. The results suggest that patient selection, procedure timing, and periprocedural medical management are critical factors to reduce periprocedural morbidity and mortality.

Adult↗
PubMed2003

Effect of age on clinical and morphological characteristics in patients with brain arteriovenous malformation.

BACKGROUND AND PURPOSE: The goal of this work was to determine the effect of age at initial presentation on clinical and morphological characteristics in patients with brain arteriovenous malformation (AVM). METHODS: The 542 consecutive patients from the prospective Columbia AVM database (mean+/-SD age, 34+/-15 years) were analyzed. Univariate statistical models were used to test the effect of age at initial presentation on clinical (AVM hemorrhage, seizures, headaches, neurological deficit, other/asymptomatic) and morphological (AVM size, venous drainage pattern, AVM brain location, concurrent arterial aneurysms) characteristics. RESULTS: Hemorrhage was the presenting symptom in 46% (n=247); 29% (n=155) presented with seizures, 13% (n=71) with headaches, 7% (n=36) with a neurological deficit, and 6% (n=33) without AVM-related symptoms. Increasing age correlated positively with intracranial hemorrhage (P=0.001), focal neurological deficits (P=0.007), infratentorial AVMs (P<0.001), and concurrent arterial aneurysms (P<0.001); an inverse correlation was found with seizures (P<0.001), AVM size (P=0.001), and lobar (P<0.001), deep (P=0.008), and borderzone (P=0.014) location. No age differences were found for sex, headache, asymptomatic presentation, and venous drainage pattern. CONCLUSIONS: Our data suggest a significant interaction of patient age and clinical and morphological AVM features and argue against uniform AVM characteristics across different age classes at initial presentation. In particular, AVM patients diagnosed at a higher age show a higher fraction of AVM hemorrhage and are more likely to harbor additional risk factors such as concurrent arterial aneurysms and small AVM diameter. Longitudinal population-based AVM data are necessary to confirm these findings.

Adolescent↗
PubMed2003

The New York Islands AVM Study: design, study progress, and initial results.

BACKGROUND AND PURPOSE: Prospective population-based data on the incidence of brain arteriovenous malformation (AVM) hemorrhage are scarce. We studied lifetime detection rates of brain AVM and incident AVM hemorrhage in a defined population. METHODS: The New York islands (ie, Manhattan Island, Staten Island, and Long Island) comprise a 9,429,541 population according to the 2000 census. Since March 15, 2000, all major New York islands hospitals have prospectively reported data on consecutive patients living in the study area with a diagnosis of brain AVM and whether the patient had suffered AVM hemorrhage. Patients living outside the ZIP code-defined study area were excluded from the study population. RESULTS: As of June 14, 2002, 284 prospective AVM patients (mean+/-SD age, 35+/-18 years; 49% women) were encountered during 21,216,467 person-years of observation, leading to an average annual AVM detection rate of 1.34 per 100,000 person-years (95% CI, 1.18 to 1.49). The incidence of first-ever AVM hemorrhage (n=108; mean age, 31+/-19 years; 45% women) was 0.51 per 100,000 person-years (95% CI, 0.41 to 0.61). The estimated prevalence of AVM hemorrhage among detected cases (n=144; mean age, 33+/-19 years; 50% women) was 0.68 per 100,000 (95% CI, 0.57 to 0.79). CONCLUSIONS: Our prospective data, spanning 27 months, suggest stable rates for AVM detection and incident AVM hemorrhage. Approximately half of AVM patients may suffer intracranial hemorrhage.

Adolescent↗
PubMed2002

Concurrent arterial aneurysms in brain arteriovenous malformations with haemorrhagic presentation.

OBJECTIVE: To assess the effect of concurrent arterial aneurysms on the risk of incident haemorrhage from brain arteriovenous malformations (AVMs). METHODS: In a cross sectional study, 463 consecutive, prospectively enrolled patients from the Columbia AVM Databank were analysed. Concurrent arterial aneurysms on brain angiography were classified as feeding artery aneurysms, intranidal aneurysms, and aneurysms unrelated to blood flow to the AVM. Clinical presentation (diagnostic event) was categorised as intracranial haemorrhage proved by imaging or non-haemorrhagic presentation. Univariate and multivariate statistical models were applied to test the effect of age, sex, AVM size, venous drainage pattern, and the three types of aneurysms on the risk of AVM haemorrhage at initial presentation. RESULTS: Arterial aneurysms were found in 117 (25%) patients with AVM (54 had feeding artery aneurysms, 21 had intranidal aneurysms, 18 had unrelated aneurysms, and 24 had more than one aneurysm type). Intracranial haemorrhage was the presenting symptom in 204 (44%) patients with AVM. In the univariate model, the relative risk for haemorrhagic AVM presentation was 2.28 (95% confidence interval (CI) 1.12 to 4.64) for patients with intranidal aneurysms and 1.88 (95% CI 1.14 to 3.08) for those with feeding artery aneurysms. In the multivariate model an independent effect of feeding artery aneurysms (odds ratio 2.11, 95% CI 1.18 to 3.78) on haemorrhagic AVM presentation was found. No significant effect was seen for intranidal and unrelated aneurysms. The attributable risk of feeding artery aneurysms for incident haemorrhage in patients with AVM was 6% (95% CI 1% to 11%). CONCLUSIONS: The findings suggest that feeding artery aneurysms are an independent determinant for increased risk of incident AVM haemorrhage.

Adult↗
PubMed2002

Risk of endovascular treatment of brain arteriovenous malformations.

BACKGROUND AND PURPOSE: Independently assessed data on frequency, severity, and determinants of neurological deficits after endovascular treatment of brain arteriovenous malformations (AVMs) are scarce. METHODS: From the prospective Columbia AVM Study Project, 233 consecutive patients with brain AVM receiving > or =1 endovascular treatments were analyzed. Neurological impairment was assessed by a neurologist using the Rankin Scale before and after completed endovascular therapy. Multivariate logistic regression models were used to identify demographic, clinical, and morphological predictors of treatment-related neurological deficits. The analysis included the components used in the Spetzler-Martin risk score for AVM surgery (AVM size, venous drainage pattern, and eloquence of AVM location). RESULTS: The 233 patients were treated with 545 endovascular procedures. Mean follow-up time was 9.6 months (SD, 18.1 months). Two hundred patients (86%) experienced no change in neurological status after treatment, and 33 patients (14%) showed treatment-related neurological deficits. Of the latter, 5 (2%) had persistent disabling deficits (Rankin score >2), and 2 (1%) died. Increasing patient age [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01 to 1.08], number of embolizations (OR, 1.41; 95% CI, 1.16 to 1.70), and absence of a pretreatment neurological deficit (OR, 4.55; 95% CI, 1.03 to 20.0) were associated with new neurological deficits. None of the morphological AVM characteristics tested predicted treatment complications. CONCLUSIONS: From independent neurological assessment and prospective data collection, our findings suggest a low rate of disabling treatment complications in this center for endovascular brain AVM treatment. Risk predictors for endovascular treatment differ from those for AVM surgery.

Adolescent↗
PubMed2002

Dysplastic vessels after surgery for brain arteriovenous malformations.

BACKGROUND AND PURPOSE: The cause and clinical significance of residual dysplastic vessels after surgery for brain arteriovenous malformations (AVM) are unclear. We studied predictors and frequency of residual dysplastic vessels on cerebral angiography after AVM surgery. METHODS: The 240 prospectively enrolled surgical patients from the New York AVM Databank underwent 269 AVM-related surgical procedures. Reported postoperative brain angiographic findings were classified post hoc as showing (1) persistent dysplastic vessels, (2) a residual AVM, (3) focal hyperemia in the surgical bed, (4) other changes, or (5) a normal angiogram. Univariate and multivariate models were applied to test for an association between residual dysplastic vessels and patient age, sex, preoperative AVM size, anatomic AVM location, number of embolization procedures before surgery, and the time interval between AVM surgery and the postoperative angiogram. RESULTS: Of the 224 documented postoperative angiograms, 78 (35%) showed dysplastic vessels, 24 (11%) had evidence for a residual AVM, 16 (7%) showed focal hyperemia, 6 (2%) revealed other findings, and 100 (45%) were normal. The number of cases showing angiographic evidence for dysplastic vessels was significantly associated with increasing size of the AVM (in millimeter increments; P=0.0001); the mean diameter of AVMs in patients showing dysplastic vessels after surgery was significantly larger (41 mm, SD +/-14) than in those without residual dysplastic vessels (27 mm, SD +/-13; P<0.001). Symptomatic postoperative intracerebral hemorrhage occurred in 4 patients (1%), in 2 of whom dysplastic vessels were seen on the postoperative angiogram. CONCLUSIONS: The findings suggest that persistent dysplastic vessels may be found in approximately one third of angiograms after AVM surgery. Preoperative AVM size was found to be an independent predictor for the occurrence of dysplastic vessels on the postoperative angiogram.

Adult↗
PubMed2001

Epidemiology and natural history of arteriovenous malformations.

The epidemiology and natural history of cerebral arteriovenous malformations (AVMs) remains incompletely elucidated. Several factors are responsible. With regard to the incidence and prevalence of AVMs, the results of prior studies have suffered because of the retrospective design, the use of nonspecific ICD-9 codes, and a focus on small genetically isolated populations. Recent data from the New York Islands AVM Hemorrhage Study, an ongoing, prospective, population-based survey determining the incidence of AVM-related hemorrhage and the associated rates of morbidity and mortality in a zip code-defined population of 10 million people, suggests that the AVM detection rate is 1.21/100,000 person-years (95% confidence interval [CI] 1.02-1.42) and the incidence of AVM-hemorrhage is 0.42/100,000 person-years (95% CI 0.32-0.55). Contemporaneous data from the Northern Manhattan Stroke Study, a prospective, longitudinal population-based study of nearly 150,000 patients in which the focus is to define the incidence of stroke, suggest the crude incidence for first-ever AVM-related hemorrhage to be 0.55/100,000 person-years (95% CI 0.11-1.61). Efforts are ongoing to study the natural history of both ruptured and unruptured AVMs in these datasets to examine the relevance of prior studies of patients selected for conservative follow up in Finland. In addition, data are being gathered to determine whether risk factors for future hemorrhage, which have previously been established in small case series, are valid when applied to whole populations. Together, these data should help inform therapeutic decisionmaking.

Adult↗
PubMed2001

Recovery of brain function during induced cerebral hypoperfusion.

We used the setting of clinically indicated internal carotid artery balloon test occlusions in 44 patients with inoperable carotid cavernous aneurysms or head and neck tumours to examine real-time changes in higher cerebral function that correlate with specific levels of cerebral blood flow. By making detailed haemodynamic and neurobehavioural measurements during the 30 min the carotid artery was occluded, we were able to quantify higher cerebral function patterns in relation to absolute cerebral blood flow (CBF) levels. We found that once the carotid artery was occluded, patients whose CBF averaged 47 ml/100 g/min (no different from baseline) maintained consistent performance on a sustained attention task; those whose CBF dropped to an average 37 ml/100 g/min had a reversible deterioration of sustained attention, and those whose CBF fell to 27 ml/100 g/min had impaired sustained attention that persisted until the carotid occlusion was reversed. The relevance of these results to the pathological state of clinical stroke is discussed with respect to the haemodynamic and physiological mechanisms that may determine how brain function is lost and regained in the setting of acute cerebral hypoperfusion.

Attention↗
PubMed2001

Anticoagulation and induced hypertension after endovascular treatment for ruptured intracranial aneurysms.

OBJECTIVE: Guglielmi detachable coil (GDC) embolization may be used to prevent early rebleeding after aneurysmal subarachnoid hemorrhage, but anticoagulation and induced hypertension may increase this risk. We sought to determine retrospectively the relationship between levels of induced hypertension and anticoagulation and incidence of rebleeding in GDC-treated patients. METHODS: Twenty-five consecutive patients with acute (<14 days) subarachnoid hemorrhage who underwent GDC embolization were retrospectively analyzed with regard to percent obliteration of an aneurysm on postprocedure angiogram, the duration and intensity of anticoagulation, the duration and level of induced hypertension, and the frequency of thromboembolic and rebleeding complications. RESULTS: Complete angiographic obliteration of the aneurysm was achieved in five cases (20%). In some cases (n = 2), only the dome of the aneurysm was coiled to allow eventual surgical clipping. Heparin was given to 23 patients (92%) for an average of 6 days (range, 8 hrs to 22 days); the mean dose was 588 units/hr, and the mean partial thromboplastin time was 37 secs. Seven patients (28%) were treated with vasopressors for symptomatic vasospasm for a mean duration of 5 days (range, 8 hrs to 9 days); mean arterial blood pressure averaged 118 mm Hg, and peak systolic blood pressures ranged from 195 to 250 mm Hg. There were no episodes of aneurysm rebleeding. Three patients (12%) suffered intraoperative thromboembolic complications, which in one instance was fatal; two of these cases were associated with subtherapeutic partial thromboplastin time values. CONCLUSION: Induced hypertension (mean arterial blood pressure, 120 mm Hg) and heparinization do not appear to increase the risk of early rebleeding after GDC embolization. In a select group of patients, use of anticoagulation in the immediate perioperative period to prevent thromboembolic complications appears to be safe.

Adult↗
PubMed2001

Evidence of increased endothelial cell turnover in brain arteriovenous malformations.

OBJECTIVE: We hypothesized that human brain arteriovenous malformations (BAVMs) are nonstatic vascular lesions with active angiogenesis or vascular remodeling. To test this hypothesis, we assessed endothelial cell turnover in BAVMs. METHODS: We identified nonresting endothelial cells by use of immunohistochemistry for the Ki-67 antigen. From archived paraffin blocks, we selected BAVM vessels without intravascular thrombosis or embolic material in areas nonadjacent to the nidus edge. For controls, we used 50- to 100-microm diameter cortical vessels from temporal lobe cortex removed for epilepsy treatment. The Ki-67 index was calculated as a percentage of Ki-67-positive endothelial cells. The data were analyzed by the nonparametric Mann-Whitney test and reported as mean +/- standard deviation. RESULTS: Thirty-seven specimens that met the above criteria were selected. There were 26 +/- 15 vessels counted in each BAVM specimen versus 18 +/- 5 in each control cortex (n = 5). The mean Ki-67 index was higher for BAVM vessels than control cortical vessels (0.7 +/- 0.6 versus 0.1 +/- 0.2%; P = 0.005), which represented an approximately seven-fold increase in the number of nonresting endothelial cells. In the BAVM group, there was a trend for younger patients to have a wider variation and higher Ki-67 index than older patients; no trend was evident in the control group. CONCLUSION: Compared with control vessels, BAVM vessels have higher endothelial cell turnover, which suggests the presence of active angiogenesis or vascular remodeling in BAVMs.

Adult↗
PubMed2001

Effect of intracarotid papaverine on human cerebral blood flow and vascular resistance during acute hemispheric arterial hypotension.

This study assessed the feasibility of augmenting cerebral blood flow (CBF) and decreasing hemispheric cerebrovascular resistance (CVR) by intracarotid papaverine during acute cerebral hypotension. Awake patients (n = 10) undergoing transfemoral balloon occlusion of an internal carotid artery (ICA) with nitroprusside (SNP)-induced systemic hypotension (10% reduction of mean arterial pressure) were studied. We measured mean femoral artery pressure (MAP), mean distal ICA pressure (P(ica)), and CBF (intracarotid 133Xe) at two time points: before and after intracarotid papaverine infusion (1 or 7 mg/min). Two patients became symptomatic immediately after ICA occlusion and were excluded. One patient developed a focal seizure during papaverine infusion. In another, the occlusion balloon deflated prematurely. Of the remaining six patients, two of the three patients who received high-dose papaverine (7 mg/min) developed transient obtundation. The remaining three patients, who received low-dose papaverine (1 mg/min), did not develop any neurologic symptoms. There was a trend for intracarotid papaverine to increase hemispheric CBF by 36% (33 +/- 10 versus 45 +/- 22 ml x 100 g(-1) x min(-1), P = .084, n = 6); papaverine decreased CVR from 1.3 +/- 0.4 to 1.0 +/- 0.3 mm Hg x ml(-1) x 100 g(-1) x min(-1) (P = .049). There was no significant change in heart rate, MAP, or P(ica) during experimental protocol. Manipulation of CVR by intracarotid papaverine during acute hemispheric arterial hypotension appears to be feasible. Further studies are needed to establish safety and efficacy.

Aged↗
PubMed2000

The experience of Wernicke's aphasia.

The authors induced a transient Wernicke's aphasia in a patient with left frontal arteriovenous malformation by superselective Wada injection exclusively into the lower division of the left middle cerebral artery. The patient was then asked to recall his experience, which the authors matched against his language during anesthesia. The patient's account showed that there was a more systematic attempt to respond appropriately than the authors could infer from his overt behavior. His narrative suggests that a thought process not measured by aphasia examinations may exist independent of language.

Aphasia, Wernicke↗
PubMed2000

Interhemispheric transfer of language in patients with left frontal cerebral arteriovenous malformation.

Cerebral arteriovenous malformations (AVMs) are frequently evaluated before therapeutic embolization by superselective injection of anesthetics into individual arterial branches so as to determine whether permanent occlusion would affect eloquent function. In Experiment 1, we used this adaptation of the Wada procedure to study three right-handed adult patients with left frontal cerebral AVMs by injecting vessels in Wernicke's and Broca's areas, respectively, and assessing language functions. The results showed that superselective testing in the inferior division of the left MCA in all three patients produced a dense Wernicke's aphasia. Injections into the left frontal regions, however, resulted in right paresis in all patients, but no language deficits including no loss of fluency. In Experiment 2, Patient 2 underwent fMRI activation for spontaneous word-list generation using multi-slice echo planar BOLD techniques at 1.5 Tesla. A voxel-by-voxel comparison of rest vs activation for each task was performed with a Z-score threshold of 2.5 SD for activated voxels. There was activation in the right hemisphere in the insula, frontal operculum pars opercularis, and inferior frontal gyrus, an area homologous to Broca's area in the left hemisphere. There was also activation in the left hemisphere in the Rolandic region, but language function was unaffected during Wada testing in this area. These data suggested that features of expressive language were no longer controlled by the left frontal lobe where the AVM was located, and provided new evidence for interhemispheric re-organization under conditions of chronic neurovascular disease.

Adult↗
PubMed2000

Intracarotid infusion of the nitric oxide synthase inhibitor, L-NMMA, modestly decreases cerebral blood flow in human subjects.

BACKGROUND: The authors hypothesized that if nitric oxide (NO) was a determinant of background cerebrovascular tone, intracarotid infusion of NG-monomethyl-L-arginine (L-NMMA), a NO synthase (NOS) inhibitor, would decrease cerebral blood flow (CBF) and intracarotid L-arginine would reverse its effect. METHODS: In angiographically normal cerebral hemispheres, after the initial dose-escalation studies (protocol 1), the authors determined the effect of intracarotid L-NMMA (50 mg/min for 5 min) on CBF and mean arterial pressure (MAP) over time (protocol 2). Changes in CBF and MAP were then determined at baseline, during L-NMMA infusion, and after L-NMMA during L-arginine infusion (protocol 3). To investigate effects of higher arterial blood concentrations of L-NMMA, changes in CBF and MAP were assessed at baseline and after a bolus dose of L-NMMA (250 mg/1 min), and vascular reactivity was tested by intracarotid verapamil (1 mg/min, protocol 4). CBF changes were also assessed during induced hypertension with intravenous phenylephrine (protocol 5). RESULTS: Infusion of L-NMMA (50 mg/min for 5 min, n = 7, protocol 2) increased MAP by 17% (86 +/- 8 to 100 +/- 11 mmHg; P < 0.0001) and decreased CBF by 20% (45 +/- 8 to 36 +/- 6 ml. 100 g-1. min-1; P < 0.005) for 10 min. Intracarotid l-arginine infusion after L-NMMA (protocol 3) reversed the effect of L-NMMA. Bolus L-NMMA (protocol 4) increased MAP by 20% (80 +/- 11 to 96+/-13 mmHg; P< 0.005), but there was no significant decrease in CBF. Intracarotid verapamil increased CBF by 41% (44+/- 8 to 62 +/- 9 ml. 100 g-1. min-1; P< 0.005). Phenylephrine-induced hypertension increased MAP by 20% (79 +/- 9 to 95 +/- 6 mmHg; P = 0.001) but did not affect CBF. CONCLUSIONS: The results suggest that intracarotid L-NMMA modestly decreases CBF, and the background tone of cerebral resistance vessels may be relatively insensitive to NOS inhibition by the intraarterial route.

Adult↗