Biomedical subjects

Michael T Lawton

Publications and source records attributed to Michael T Lawton.

At least 19 recordsLinked to original sources

PubMed2006

MMP-9 expression is associated with leukocytic but not endothelial markers in brain arteriovenous malformations.

Brain arteriovenous malformations (BAVM) have high matrix metalloproteinase-9 (MMP-9) expression, the source of which is unclear. We hypothesized MMP-9 production might be due to inflammation in BAVM. Compared to control brain tissues (n = 5), BAVM tissue (n = 139) had a higher expression (by ELISA) of myeloperoxidase (MPO) (193 +/- 189 vs. 6 +/- 3, ng/mg, P < .001), MMP-9 (28 +/- 32 vs. 0.7 +/- 0.6, ng/mg, P < .001), and IL-6 (102 +/- 218 vs. 0.1 +/- 0.1, pg/mg, P < .001), but not eNOS (114 +/- 87 vs. 65 +/- 9, pg/mg, P = .09). MMP-9 expression in BAVM highly correlated with myeloperoxidase (R2 = .76, P < .001), as well as with IL-6 (R2 = .32, P < .001). In contrast, MMP-9 in BAVM poorly correlated with the endothelial marker, eNOS (R2 = .03, P = .05), and CD31 (R2 = .004, P = .57). Compared to non-embolized patients (n = 46), patients with pre-operative embolization (n = 93) had higher levels of myeloperoxidase (236 +/- 205 vs. 106 +/- 108, ng/mg, P < .001) and MMP-9 (33 +/- 35 vs. 16 +/- 20, ng/mg, P < .001), however the correlation between MMP-9 and myeloperoxidase was equally strong for both groups (R2 = .69, n = 93, P < .001, for both). MMP-9 expression correlated with the lipocalin-MMP-9 complex, suggesting neutrophils as the MMP-9 source. MPO co-localized with majority of MMP-9 signal by immunohistochemistry. Our data suggest that inflammation is a prominent feature of BAVM lesional phenotype, and neutrophils appear to be a major source of MMP-9 in these lesions.

Adult↗

PubMed2006

Interleukin-6 upregulates expression of KDR and stimulates proliferation of human cerebrovascular smooth muscle cells.

Interleukin-6 (IL-6) may play multiple roles in angiogenesis and vascular remodeling. Our previous study showed that a promoter polymorphism (174G>C) in IL-6 is associated with brain arteriovenous malformation hemorrhage; tissue expression is related to genotype. In this study, we investigated the effects of IL-6 on human cerebral smooth muscle cells (HCSMCs) and smooth muscle cells isolated from brain arteriovenous malformation surgical specimens (AVM SMCs) and surgical controls (control HCSMCs--from structurally normal temporal lobe taken during surgical treatment of epilepsy patients). We found that IL-6 (1.1+/-0.27 versus 0.37+/-0.04 pg/mL, n=5, P<0.05) and endogenous vascular endothelial growth factor (VEGF) receptor II (kinase domain-containing receptor (KDR), 15+/-3 versus 1.5+/-3 pg/mL, n=5, P<0.05) were increased in brain AVM SMCs compared with control HCSMCs. Further research revealed that IL-6 could stimulate SMC proliferation, VEGF release, and KDR activation in control HCSMCs. It could also stimulate KDR phosphorylation in control HCSMCs, further confirming a unique role of IL-6 in the triggering of KDR. Interleukin-6 could increase matrix metalloproteinase-9 (MMP-9) secretion through activating KDR in control HCSMCs (P<0.05 versus control). Inhibiting IL-6-induced KDR could reduce MMP-9 activity at least 50% compared with the control group (P<0.05). Increased MMP-9 activity was accompanied by increased control HCSMC proliferation, and blocking MMP-9 activity significantly reduced IL-6-induced control HCSMC proliferation (P<0.05). Collectively, our results show that IL-6 could activate, amplify, and maintain the angiogenic cascade in HCSMCs. A novel role of IL-6 during HCSMC proliferation is upregulating KDR expression and phosphorylation. The results may contribute to the angiogenic phenotype of human brain vascular diseases, such as brain AVM.

Adult↗

PubMed2006

Adrenoceptor polymorphisms and the risk of cardiac injury and dysfunction after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Cardiac abnormalities occur commonly after subarachnoid hemorrhage (SAH) and may be caused by excessive release of catecholamines from the myocardial sympathetic nerves. We hypothesized that adrenoceptor polymorphisms resulting in greater catecholamine sensitivity would be associated with an increased risk of cardiac injury. METHODS: This was a prospective cohort study. The primary outcome variables were the serum level of cardiac troponin I (cTi, abnormal if >1.0 microg/L) and the left ventricular ejection fraction (LVEF, abnormal if <50%). Six adrenoceptor polymorphisms were genotyped: beta1AR Arg389Gly, beta1AR Ser49Gly, beta2AR Gly16Arg, beta2AR Gln27Glu, beta2AR Thr164Ile, and alpha2AR del322-325. The effect of each polymorphism on the risk of developing cardiac abnormalities was quantified using multivariable logistic regression. RESULTS: The study included 182 patients. The CC genotype (Arg/Arg) of beta1AR Arg389Gly (odds ratio [OR] 3.4, P=0.030) and the CC genotype (Gln/Gln) of beta2AR Gln27Glu (OR 3.1, P=0.032) were predictive of cTi release. The presence of the alpha2AR deletion was predictive of reduced LVEF (OR 4.2, P=0.023). The combination of the beta1AR 389 CC and the beta2AR 27 CC genotypes resulted in a marked increase in the odds of cTi release (OR 15.5, P=0.012). The combination of the beta1AR 389 CC and the alpha2AR deletion genotypes resulted in a marked increase in the odds of developing a reduced LVEF (OR 10.3, P=0.033). CONCLUSIONS: Genetic polymorphisms of the adrenoceptors are associated with an increased risk of cardiac abnormalities after SAH. These data support the hypothesis that cardiac dysfunction after SAH is a form of neurocardiogenic injury.

Catecholamines↗

PubMed2006

Interleukin-6 involvement in brain arteriovenous malformations.

We recently reported that the GG genotype of the interleukin-6 (IL-6)-174G>C promoter polymorphism is associated with clinical presentation of intracranial hemorrhage in brain arteriovenous malformation (AVM) patients. In this study, we investigated whether tissue IL-6 expression was associated with IL-6-174G>C genotype, and whether IL-6 was linked to downstream targets involved in angiogenesis and vascular instability. Our results showed that the highest IL-6 protein levels in brain AVM tissue were associated with IL-6-174GG genotype (GG: 57.7 +/- 20.2; GC: 35.6 +/- 26.6; CC: 13.9 +/- 10.2pg/mg; p = 0.001). IL-6 protein levels were increased in AVM tissue from patients with hemorrhagic presentation compared with patients without hemorrhage (55 +/- 22 vs 40 +/- 27pg/mg; p = 0.038). IL-6 messenger RNA expression strongly correlated with messenger RNA levels of IL-1beta, tumor necrosis factor-alpha, IL-8, matrix metalloproteinase-3 (MMP-3), MMP-9, and MMP-12. We further investigated the plausibility of IL-6 being an upstream cytokine responsible for initiating the angiogenic cascade by cell culture and animal experiments. IL-6 induced MMP-3 and MMP-9 expression and activity in mouse brain and increased proliferation and migration of cerebral endothelial cells. Together, our results suggest that the IL-6 genotype associated with intracranial hemorrhage modulates IL-6 expression in brain AVM tissue, which is consistent with the hypothesis that inflammatory processes induce angiogenic activity possibly contributory to brain AVM intracranial hemorrhage.

Adult↗

PubMed2006

The extended retrosigmoid approach: an alternative to radical cranial base approaches for posterior fossa lesions.

OBJECTIVE: The extended retrosigmoid approach is presented as a simple and safe modification of the traditional retrosigmoid approach, with increased exposure resulting from a limited mastoidectomy and skeletonization of the sigmoid sinus. METHODS: Patients with posterior fossa vascular lesions treated with the extended retrosigmoid approach between 1997 and 2003 were reviewed. A detailed description of the surgical approach, as well as case illustrations, is provided. We present a video narrated by the senior author in which a description of the technique is offered. RESULTS: Thirty-eight patients underwent this approach to manage 40 lesions, including 15 dural arteriovenous fistulae, 9 arteriovenous malformations, 10 cavernous malformations, and 6 aneurysms. The extended retrosigmoid approach differs from the traditional approach with its C-shaped skin incision, posterior mastoidectomy, and extensive dissection of the sigmoid sinus, craniotomy rather than craniectomy, and anterior mobilization of the sinus with the dural flap. CONCLUSION: The application of the extended retrosigmoid approach to a series of complex lesions in the posterior fossa demonstrates its applicability as an alternative to radical cranial base approaches. The extended retrosigmoid approach requires a fundamental change in the management of the sigmoid sinus. The neurosurgeon must be familiar with petrous bone anatomy, experienced dissecting through bone using a high-speed drill, and comfortable working directly over a major venous sinus. The technical modifications of the extended retrosigmoid approach can be incorporated into the neurosurgical repertoire and will enhance exposure of the cerebellopontine angle and deep vascular structures, thereby minimizing the need for brain retraction and other transpetrous approaches.

Adult↗

PubMed2006

Double reimplantation technique to reconstruct arterial bifurcations with giant aneurysms.

OBJECTIVE: To introduce the double implantation technique, a variation of standard radial artery or saphenous vein bypass that can be used to reconstruct arterial bifurcations in the management of giant aneurysms with complex branch arteries. METHODS: This technique was applied in two patients with giant aneurysms. A 74-year-old woman presented with a ruptured thrombotic middle cerebral artery aneurysm, and a 24-year-old man presented with an enlarging infectious aneurysm of the distal anterior cerebral artery (ACA). RESULTS: In the first case, a saphenous vein graft was anastomosed end-to-end to the external carotid artery. The temporal M2 middle cerebral artery trunk was disconnected from the aneurysm and reimplanted onto the graft with an end-to-side anastomosis. The graft was anastomosed end-to-side to the frontal M2 middle cerebral artery trunk, and the aneurysm was trapped. Similarly, in the second case, a radial artery graft was connected to a proximal ACA branch (anterior internal frontal artery) and to the distal pericallosal artery, with reimplantation of the callosomarginal artery onto the graft. The aneurysm was occluded proximally with a clip. CONCLUSION: The combination of two arterial reimplantations onto a bypass graft connected to a proximal donor artery (3 anastomoses overall) reconstructs an arterial bifurcation and enables the exclusion of a giant aneurysm. Ischemia times are minimized by completing the proximal anastomosis first, successively reimplanting efferent arterial trunks distally, and restoring cerebral perfusion to reimplanted arteries while other anastomoses are performed. This technique may be indicated when critical efferent arteries require revascularization, conventional donor arteries are diminutive, the aneurysm has ruptured, or intraluminal thrombus requires debulking.

Adult↗

PubMed2006

Apolipoprotein E epsilon 2 is associated with new hemorrhage risk in brain arteriovenous malformations.

OBJECTIVE: Patients with brain arteriovenous malformation (AVM) are at life-threatening risk of intracranial hemorrhage (ICH). Identification of genetic variants associated with increased new ICH risk would facilitate risk stratification and guide therapeutic intervention. METHODS: Brain AVM patients evaluated at University of California, San Francisco or Kaiser Permanente Northern California were followed longitudinally. Primary outcome was new ICH after diagnosis; censoring events were any AVM treatment or last follow-up examination. The association of ApoE epsilon2 and epsilon4 genotype with new ICH was evaluated by Kaplan-Meier survival analysis and further characterized via a Cox proportional hazards model. RESULTS: We genotyped 284 brain AVM patients (50% women; 57% Caucasian; median follow-up time, 0.3 yr) including 18 patients with a history of new ICH). ApoE epsilon2, but not ApoE epsilon4 genotype, was associated with new ICH (P = 0.0052). ApoE epsilon2 carriers had fivefold increased risk of new ICH (hazard ratio, 5.09; 95% confidence interval, 1.46-17.7; P = 0.010; Cox proportional hazards model adjusting for race/ethnicity and clinical presentation). Subset analysis in the largest homogenous ethnic subcohort (Caucasians) confirmed the increased risk of new ICH in ApoE epsilon2 carriers (hazard ratio, 8.71; 95% confidence interval, 1.4-53.9; P = 0.020; multivariate model adjusting for clinical presentation). CONCLUSION: ApoE genotype may influence the risk of ICH in the natural course of brain AVM. The identification of genetic predictors of ICH risk may facilitate estimation of AVM natural history risk and individualize clinical decision-making and therapeutic recommendations.

Adult↗

PubMed2006

Posterior interhemispheric approach: surgical technique, application to vascular lesions, and benefits of gravity retraction.

OBJECTIVE: To review an experience with the posterior interhemispheric approach applied to vascular lesions in the posterior midline, to examine the effects of patient position and gravity retraction of the occipital lobe, and to identify circumstances requiring increased exposure by sectioning the falx and tentorium. METHODS: During a 6.5-year period, 46 posterior interhemispheric approaches were performed to treat 28 arteriovenous malformations, 10 dural arteriovenous fistulae, seven cavernous malformations, and one posterior cerebral artery aneurysm. Twenty-three patients were positioned prone and 23 patient were positioned laterally. RESULTS: A standard posterior interhemispheric approach was used in 38 patients, and the occipital bitranstentorial/falcine approach was used in seven patients. A contralateral occipital transfalcine approach was used with one thalamic cavernous malformation. All lesions were resected completely and/or obliterated angiographically, with good neurological outcomes in 83% of patients and no operative mortality. Blood loss was lower, operative durations were shorter, postoperative cerebral edema was decreased, and visual outcomes were improved in patients positioned laterally. CONCLUSION: The posterior interhemispheric approach, without additional dural cuts, is appropriate for most vascular lesions in the posterior midline. Gravity retracts the occipital lobes when patients are positioned laterally, enhancing operative exposure and reducing morbidity. Extension of the posterior interhemispheric approach to a transtentorial or transfalcine approach is required for falcotentorial dural arteriovenous fistulae and vein of Galen arteriovenous malformations, but is not usually necessary with cavernous malformations or other arteriovenous malformations.

Adolescent↗

PubMed2006

The "yo-yo" technique to prevent cerebrospinal fluid rhinorrhea after anterior clinoidectomy for proximal internal carotid artery aneurysms.

OBJECTIVE: Resection of the anterior clinoid process is important for the exposure of aneurysms on clinoidal and supraclinoidal segments of the internal carotid artery. Cerebrospinal fluid (CSF) rhinorrhea can complicate anterior clinoidectomy when the optic strut is pneumatized and its removal communicates the subarachnoid space with the sphenoid sinus. We present a technique for repairing this defect and preventing CSF rhinorrhea. METHODS: A suture is secured around a strip of temporalis muscle, which is then pushed through the opening in the optic strut completely into the sphenoid sinus. The ends of suture that trail the muscle are used to retract the muscle from the sphenoid sinus back into the optic strut. The suture is trimmed and the repair is covered with sealant or fibrin glue. RESULTS: During an 8-year period in which 127 patients with proximal internal carotid artery aneurysms that required anterior clinoidectomy were treated, pneumatized optic struts were encountered in 14 patients (11%). Four patients were treated with the "yo-yo" technique, none of whom experienced CSF rhinorrhea. Before using this technique, 10 patients were managed with standard packing techniques (wax, muscle, and gel foam) and four of these patients subsequently experienced CSF rhinorrhea (40%). In these four patients, all required reoperation with either craniotomy and packing with pericranium (one patient), Couldwell-Luc procedure (one patient), or endoscopic transnasal obliteration of the sphenoid sinus with fat (two patients). CONCLUSION: The "yo-yo" technique of tightly wedging a muscle plug into the optic strut proved to be simple, fast, and effective, preventing CSF rhinorrhea in all patients in whom it was applied. Although experience with this technique is limited, reversing the direction of packing and pulling muscle from the sphenoid sinus into the optic strut eliminated a complication that occurred in 40% of patients with standard packing techniques.

Carotid Artery, Internal↗

PubMed2006

Estimating the hemodynamic impact of interventional treatments of aneurysms: numerical simulation with experimental validation: technical case report.

OBJECTIVE: The goal of this study was to use phase-contrast magnetic resonance imaging and computational fluid dynamics to estimate the hemodynamic outcome that might result from different interventional options for treating a patient with a giant fusiform aneurysm. METHODS: We followed a group of patients with giant intracranial aneurysms who have no clear surgical options. One patient demonstrated dramatic aneurysm growth and was selected for further analysis. The aneurysm geometry and input and output flow conditions were measured with contrast-enhanced magnetic resonance angiography and phase-contrast magnetic resonance imaging. The data was imported into a computational fluid dynamics program and the velocity fields and wall shear stress distributions were calculated for the presenting physiological condition and for cases in which the opposing vertebral arteries were either occluded or opened. These models were validated with in vitro flow experiments using a geometrically exact silicone flow phantom. RESULTS: Simulation indicated that altering the flow ratio in the two vertebrals would deflect the main blood jet into the aneurysm belly, and that this would likely reduce the extent of the region of low wall shear stress in the growth zone. CONCLUSIONS: Computational fluid dynamics flow simulations in a complex patient-specific aneurysm geometry were validated by in vivo and in vitro phase-contrast magnetic resonance imaging, and were shown to be useful in modeling the likely hemodynamic impact of interventional treatment of the aneurysm.

Aged↗

PubMed2006

Expression of hypoxia-inducible factor-1 and vascular endothelial growth factor in response to venous hypertension.

OBJECTIVE: Experimentally, a fistula created surgically between the carotid artery and jugular vein, together with occlusion of venous sinuses, generate venous hypertension, which can induce dural arteriovenous fistula formation intracranially in rats. Our aim was to study the effect of nonischemic venous hypertension on the elaboration of the angiogenic signal, hypoxia-inducible factor-1 (HIF-1), and its downstream signal, vascular endothelial growth factor (VEGF). METHODS: Sixty rats were exposed to venous hypertension for periods ranging from 4 hours to 3 weeks. Western blot analysis, transbinding assays, enzyme-linked immunosorbent assays, and immunohistochemistry quantified HIF-1 and VEGF expression in brain. Forty-eight control rats underwent similar surgical procedures without creating venous hypertension. Cerebral blood flow was measured at baseline, after surgery, and before sacrifice. RESULTS: Venous hypertension did not impair cerebral blood flow. Relative to controls, HIF-1 expression increased fivefold in response to venous hypertension (P < 0.005), with peak expression 1 day later localized to endothelial cells in venules next to the sagittal sinus. VEGF expression also increased threefold in response to venous hypertension (P < 0.05), with peak expression 7 days later localized to parasagittal astrocytes. HIF-1 and VEGF were minimally expressed in rat normal venous pressures. CONCLUSION: In this model, venous hypertension stimulates angiogenesis by a mechanism other than ischemia. HIF-1 expression may result from dilation of parasagittal veins and endothelial deformation. HIF-1 and VEGF seem to be molecular agents that convert venous hypertension into intracellular signals and angiogenesis activity.

Animals↗

PubMed2006

The supratonsillar approach to the inferior cerebellar peduncle: anatomy, surgical technique, and clinical application to cavernous malformations.

OBJECTIVE: To introduce the supratonsillar approach, an approach that traverses the tonsillobiventral fissure in a trajectory over the cerebellar tonsil to the inferior cerebellar peduncle, and to demonstrate the utility of this approach for resecting peduncular cavernous malformations. METHODS: Anatomy of the cerebellar tonsil and surrounding fissures, arteries, and veins are reviewed using cadaveric brain specimens. The surgical approach uses the three-quarter prone position, a suboccipital craniotomy, and wide splitting of the tonsillobiventral fissure. RESULTS: Of our experience with 171 patients with cavernous malformations, six patients had lesions in the inferior cerebellar peduncle that were resected using the supratonsillar approach. All cavernous malformations were removed completely and no patients experienced surgical complications or new deficits. CONCLUSION: The supratonsillar approach differs from the transvermian and telovelar approaches to the fourth ventricle, with a more superolateral trajectory that leads instead to the inferior cerebellar peduncle. By splitting the tonsillobiventral fissure and mobilizing the tonsil inferomedially, the point of access to the lesion is deepened and transgression of normal cerebellar tissue is minimized. This elegant approach is ideally suited to the removal of cavernous malformations.

Adult↗

PubMed2006

Predictors of left ventricular regional wall motion abnormalities after subarachnoid hemorrhage.

INTRODUCTION: Cardiac abnormalities that have been reported after subarachnoid hemorrhage (SAH) include the release of cardiac biomarkers, electrocardiographic changes, and left ventricular (LV) systolic dysfunction. The mechanisms of cardiac dysfunction after SAH remain controversial. The aim of this study was to determine the prevalence of LV regional wall motion abnormalities (RWMA) after SAH and to quantify the independent effects of specific demographic and clinical variables in predicting the development of RWMA. METHODS: Three hundred patients hospitalized with SAH were prospectively studied with serial echocardiography. The primary outcome measure was the presence of RWMA. The predictor variables included the admission Hunt & Hess grade, age, gender, cardiac risk factors, aneurysm location, plasma catecholamine levels, cardiac troponin I (cTi) level, heart rate (HR), blood pressure, and phenylephrine dose. Univariate and multivariate logistic regression was performed with adjustment for serial measurements, reporting odds ratios (OR) and 95% confidence intervals (CI). RESULTS: In this study, 817 echocardiograms were analysed. RWMA were detected in 18% of those studied. The prevalence of RWMA in patients with Hunt & Hess grades 3 - 5 was 35%. Among patients with a peak cTi level greater than 1.0 m g/L, 65% had RWMA. Multivariate analysis demonstrated that high Hunt & Hess grade (OR 4.22 for grade 3 - 5 versus grade 1 - 2, p = 0.046), a cTi level greater than 1.0 microg/L (OR 10.47, p = 0.001), a history of prior cocaine or amphetamine use (OR 5.50, p = 0.037), and higher HR (OR 1.34 per 10 bpm increase, p = 0.024) were predictive of RWMA. CONCLUSIONS: RWMA were frequent after SAH. High-grade SAH, an elevation in cTi levels, a history of prior stimulant drug use, and tachycardia are independent predictors of RWMA.

Adolescent↗

PubMed2006

Cardiovascular predictors of in-patient mortality after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Whether cardiac dysfunction contributes to morbidity and mortality after subarachnoid hemorrhage (SAH) remains controversial. The objective of this study was to test the hypothesis that cardiovascular abnormalities are independently related to in-patient mortality after SAH. METHODS: This was a prospective cohort study of patients with aneurysmal SAH. Heart rate and blood pressure were measured, a blood sample was obtained, and echocardiography was performed on three study days, starting as soon after admission as possible. The cardiovascular predictor variables were heart rate, systolic blood pressure (SBP), cardiac troponin I (cTi) level, B-type natriuretic peptide (BNP) level, and left ventricular ejection fraction. The primary outcome measure was in-patient mortality. The association between each predictor variable and mortality was quantified by multivariate logistic regression, including relevant covariates and reporting odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The study included 300 patients. An initial BNP level greater than 600 pg/mL was markedly associated with death (OR 37.7, p < 0.001). On the third study day (9.1 +/- 4.1 days after SAH symptom onset), a cTi level greater than 0.3 mg/L (OR 7.6, p = 0.002), a heart rate of 100 bpm or greater (OR 4.9, p = 0.009), and a SBP less than 130 mmHg (OR 6.7, p = 0.007) were significantly associated with death. CONCLUSIONS: Cardiovascular abnormalities are independent predictors of in-patient mortality after SAH. Though these effects may be explained by a reduction in cerebral perfusion pressure or other mechanisms, further research is required to determine whether or not they are causal in nature.

Adult↗

PubMed2006

Prospective analysis of prevalence, distribution, and rate of recovery of left ventricular systolic dysfunction in patients with subarachnoid hemorrhage.

OBJECT: Subarachnoid hemorrhage (SAH) has been associated with cardiac injury and left ventricular (LV) dysfunction. The incidence and natural history of neurocardiogenic injury after SAH remains poorly understood. The objective of this study was to describe the incidence, time course, recovery rate, and segmental patterns of LV dysfunction after SAH. METHODS: Echocardiography was performed three times over a 7-day period in 173 patients with SAH. The incidence of global (ejection fraction [EF] < 50%) and segmental (any regional wall-motion abnormality [RWMA]) LV dysfunction was measured. The time course of LV dysfunction was determined by comparing the prevalence of LVEF less than 50% and RWMA at 0 to 2, 3 to 5, and 6 to 8 days after SAH. The recovery rate was defined as the proportion of patients with partial or complete normalization of function. The distribution of RWMAs among 16 LV segments was also determined. An LVEF less than 50% was found in 15% of patients, and 13% had an RWMA with a normal LVEF. There was a trend toward increased dysfunction at 0 to 2 days after SAH, compared with 3 to 8 days after SAH. Recovery of LV function was observed in 66% of patients. The most frequently abnormal LV segments were the basal and middle ventricular portions of the anteroseptal and anterior walls. The apex was rarely affected. CONCLUSIONS: Left ventricular systolic dysfunction occurs frequently after SAH and usually improves over time. The observed segmental patterns of LV dysfunction often do not correlate with coronary artery distributions.

Adult↗

PubMed2006

Pediatric intracranial aneurysms: durability of treatment following microsurgical and endovascular management.

OBJECT: Longer life expectancies and differences in the underlying disease in children with aneurysms raise important issues concerning the choice of microsurgical or endovascular therapy. The authors reviewed their experience at one institution regarding patients treated between 1977 and 2003, focusing on the issue of treatment durability. METHODS: Forty-three aneurysms in 32 pediatric patients were identified. The patients ranged in age from 2 months to 18 years (mean 11.7 years). Only seven patients (22%) presented with subarachnoid hemorrhage, and in nine patients (28%) significant medical comorbidities were present. Aneurysm locations included the internal carotid artery (13 lesions), middle cerebral artery (11 lesions), and the basilar artery/vertebrobasilar junction (six lesions). Of the 43 lesions, 17 (40%) were giant aneurysms and 22 (51%) exhibited fusiform/dolichoectatic morphological features. Thirteen patients underwent microsurgery, 16 endovascular treatment, and three observation. Complete aneurysm obliteration rates were 94 and 82% in the microsurgical and endovascular groups, respectively. There were no deaths in either group, and neurological morbidity rates were comparable. Over time, 14% of endovascularly treated aneurysms recurred, and in 19% of these patients de novo aneurysms developed (mean follow-up duration 5.7 years). In contrast, there were no recurrences in the microsurgically treated aneurysms and only one de novo aneurysm (6%). CONCLUSIONS: Both microsurgical and endovascular therapies can be conducted safely to treat pediatric aneurysms. Microsurgery may be more efficacious in completely eliminating the aneurysm and its effects more durable over the extended lifetime of these patients. Parental biases toward nonoperative therapy should be thoroughly addressed before ultimately selecting a treatment strategy.

Adolescent↗

PubMed2006

Superior outcomes in children compared with adults after microsurgical resection of brain arteriovenous malformations.

OBJECT: Young age is considered an important factor in determining outcomes after microsurgical resection of arteriovenous malformations (AVMs), but better results in children have not been adequately explained. A consecutive series of pediatric and adult patients was reviewed to determine whether differences in outcomes between these two groups were due to differences in AVM anatomy, rupture rates, neurological condition at presentation, treatment techniques, or other causes. METHODS: As assessed using the modified Rankin Scale (mRS), patient characteristics, clinical presentation, AVM anatomy, treatment techniques, and outcomes were compared between age groups. Thirty-two pediatric and 192 adult patients underwent microsurgical AVM resection during a 6.4-year period; complete resection was achieved in 97% of the children and 98% of adults. Superior outcomes were observed in children, who had better final mRS scores (p = 0.003) and more favorable changes in these scores (the condition of 94% of children improved or remained unchanged, compared with 70% of adults; p = 0.001). The change in the mean mRS scores was 1.31 for children and 0.14 for adults (p = 0.001). There were no significant clinical, anatomical, or therapeutic differences between children and adults. CONCLUSIONS: This analysis confirms the observation that children fare better than adults after microsurgical AVM resection. This discrepancy cannot be explained by differences in AVM anatomy, lesion rupture rates, presenting neurological condition, or treatment techniques, leading the authors to infer that neural plasticity may augment surgical tolerance and recovery in children. These findings bolster the choice of aggressive microsurgical management of AVMs and recalibration of surgical risk assessment in children.

Adult↗

PubMed2006

Sacral epithelioid angiosarcoma associated with a bleeding diathesis and spinal epidural hematoma: case report.

Epithelioid angiosarcoma of bone is a rare, high-grade lesion that is highly vascular and can be associated with a bleeding diathesis. An association has been reported in angiosarcomas in other locations with coagulopathy from tumor-related disseminated intravascular coagulopathy and fibrinolysis. The authors report the case of a rare occurrence of a primary sacral epithelioid angiosarcoma associated with a large epidural hematoma and a severe bleeding diathesis. A 25-year-old woman presented with weakness, fatigue, neck and low-back pain, and progressive left S-1 radiculopathy. Imaging studies revealed a large ventral epidural hematoma extending from the sacral region rostrally to C-2 and a vascular tumor located in the sacrum. The patient underwent a sacral laminectomy, complicated by postoperative bleeding from the wound, and required massive transfusions. Ultimately, multimodal therapy was required to obtain hemostasis, including the use of endovascular embolization, radiation therapy, and an infusion of epsilon-aminocaproic acid with heparin. This case represents the first report of a primary epithelioid angiosarcoma in the sacrum and emphasizes that the coagulopathy seen in angiosarcoma is also a feature of this epithelioid variant.

Adult↗