Differential therapy of cerebral arteriovenous malformations. An analysis with reference to personal microsurgery experiences

A total of 126 patients (63 female, 63 male) underwent microsurgical removal of their cerebral arteriovenous malformations (AVMs) by the same surgeon. The mean age at surgery was 34.7 (6-72) years. The symptoms were intracerebral hemorrhage (37.3%), seizure disorder (34.9%) or focal neurological deficits and minor symptoms. According to the Spetzler/Martin scale, 20.6% of the AVMs were grade I, 28.6% grade II, 32.5% grade III, 14.3% grade IV and 4% grade V. In all, 78 AVMs (61.9%) were located in functionally important brain regions. The series was split into three different groups: small AVMs under 3 cm in diameter (n = 62/49.2%), medium-sized AVMs (n = 58/46%) and large AVMs (n = 6/4.8%). Seventeen patients had preoperative embolization of their AVM. All patients had postoperative angiographic control and 3- and 6-month follow-up. One patient died (0.8%), and another one (0.8%), in whom the AVM was incompletely resected, suffered a secondary hemorrhage. Seventeen (27.4%) of the patients with small AVMs developed transient neurological worsening post-operatively, which remained permanently significant in 3.2%. The respective numbers for the patients with medium-sized AVMs were 48.3% and 10.3% and for the large AVMs 83.3% and 33.3%. The results of microsurgical removal of cerebral AVMs can still be considered superior to the results of stereotactic radiosurgical treatment available from the literature-even for small AVMs. This is due to immediate exclusion of the AVM under direct local control of the angioarchitecture and thereby a reduced risk of secondary hemorrhaging and a decreasing morbidity rate with increasing time after the operation. Radiosurgical treatment requires a 2-year latency period for obliteration and carries a mortality rate of up to 12.5% and a rate of unexpected side effects of up to 20%. This treatment should be reserved for small, deep, surgically inaccessible AVMs or used as part of a multimodality treatment regimen consisting of partial embolization, partial excision and consecutive radiation of the residual nidus in initially very large AVMs. Embolization therapy-such as radiosurgery-carries a significant risk of morbidity (8%) and a mortality rate of up to 6%. It should only be considered for AVMs that are expected to be fully obliterated afterwards, or for primary inoperable AVMs that are to be changed into operable ones by embolization. Size reduction of otherwise operable AVMs does not justify the additional risk of embolization. Close collaboration of the specialties involved is desirable.     

Transluminal angioplasty and intra-arterial papaverine for the treatment of cerebral vasospasm after ruptured arteriovenous malformations

BACKGROUND: This is the first report on the use of intra-arterial papaverine and percutaneous transluminal angioplasty in two patients with severe, symptomatic cerebral vasospasm who suffered ruptured arteriovenous malformations (AVMs). CASE DESCRIPTIONS: The source of hemorrhage was a venous aneurysm in the first case and a pedicular aneurysm of the distal posterior inferior cerebellar artery in the second case. In both cases, the AVMs were located in the superior vermis and there was minimal subarachnoid hemorrhage. The first patient underwent removal of the AVM before the period of cerebral vasospasm and the second patient underwent removal of the AVM after the cerebral vasospasm had resolved. The outcome was excellent in the first patient and poor in the second patient. CONCLUSION: Arteriovenous malformation with ruptured aneurysms may be at high risk for cerebral vasospasm even when there is minimal subarachnoid hemorrhage. We recommend early treatment of AVMs with ruptured pedicular, intranidal, or venous aneurysms to avoid rebleeding and to allow for aggressive treatment of cerebral vasospasm. The management of cerebral vasospasm after AVM rupture is discussed.     

The value of intraoperative angiography for surgical treatment of cerebral arteriovenous malformations in eloquent brain areas

Intraoperative digital subtraction angiography (DSA) allows intraoperative assessment of outcome of cerebral arteriovenous malformations (AVM). This study reports on 21 patients with AVMs in eloquent areas of the brain extirpated between July 1995 to March 1998. Extirpation was always followed by intraoperative DSA. Intraoperative angiography disclosed an occult residual nidus in 4 cases (19%). Complete extirpation of the AVM was achieved in all cases. Following surgery the neurological condition improved in 15 cases (71%), remained unchanged in 5 (24%), and worsened in 1. There were no secondary postoperative haemorrhages, nor complications related to the angiography. These results indicate that intraoperative DSA should be considered in the course of surgical treatment of cerebral AVMs in eloquent areas of the brain.     

Combinatorial selection of a small RNA that induces amplification of IncFII plasmids in Escherichia coli

Patients with arteriovenous malformation (AVM)-associated aneurysms are a well-recognized subset of the cerebrovascular disease population. The origin of these dual lesions is likely multifactorial, with hemodynamic stresses having a dominant influence. In most patients who present with hemorrhage, the aneurysm is the usual source. Since aneurysm rupture continues to carry a more significant morbidity and mortality when compared to AVM hemorrhage, the authors recommend that the aneurysm be treated first or simultaneously with the AVM in the majority of cases. Treatment of the AVM first is primarily reserved for patients who have suffered bleeds from resectable AVMs.     

Vitamin E modulation of dieldrin-induced hepatic focal lesion growth in mice

The purposes of this study were to determine the safety and efficacy of embolization of brain AVMs prior to radiosurgery and to evaluate the total obliteration rate achieved. The brain AVMs of 64 patients were subselectively embolized mainly with NBCA, platinum microcoils and/or PVA. The aim of embolization was the reduction of the target volume and/or the elimination of vascular structures bearing an increased risk of hemorrhage. Presenting symptoms were intracranial hemorrhage in 33 patients, a seizure disorder in 21 patients, and headache in 6 patients. Four AVMs had been detected as an incidental finding. The initial AVM volume was in the range of 0.5 to 84 cc (mean 17 cc). Grading of the AVMs according to the Spetzler-Martin scale showed the following distribution: grade I, 3x; II, 13x; III, 11x; IV, 17x; V, 4x; VI, 16x. A total of 300 endovascular procedures including 47 subselective catheterizations without and 253 with embolization were performed. A size reduction of the AVMs between 10% and 95% (mean 63%, median 70%) was achieved. Neurological symptoms due to treatment complications were transient in 12 patients, of minor clinical significance but permanent in 4 patients. Following radiosurgery, one patient died due to recurrent intracerebral hemorrhage. Three patients are doing well but refused final follow-up angiography. A total of 30 patients is currently within the latency interval after radiosurgery. Radiosurgery failed to obliterate the embolized AVMs in 16 patients. Angiography confirmed complete nidus obliteration in 14 patients. The endovascular treatment of brain AVMs prior to radiosurgery proved safe and effective and may be considered in either high grade or incidental AVMs. AVM obliteration after embolization and radiosurgery is less frequently achieved than after stereotactic irradiation of primarily small AVMs.     

A comparison of hydroxyapatite-coated, titanium-coated, and uncoated tapered external-fixation pins. An in vivo study in sheep

OBJECTIVES: This study focuses on the relevance of size, eloquence, type of venous drainage, the Spetzler-Martin scale as a whole, and other factors, such as rupture of cerebral arteriovenous malformations (AVMs) for the prediction of neurological deficits in the context of microsurgical AVM removal. METHODS: One hundred and fifty patients with AVMs, whose data were retrieved from a prospectively employed computerised data bank were included. Seventeen patients (11.3%) underwent preoperative embolisation. According to the Spetzler-Martin scale they were graded as follows: 22.0% grade I, 32.0% grade II, 29.3% grade III, 14.0% grade IV, and 2.7% grade V. Intracerebral haemorrhage was present in 39.0%. The AVMs were <3 cm in 52.00/0, 3-6 cm in 43.3% and >6 cm in 4.7%; 59.3% of the AVMs were eloquently located and 29.3% had deep venous drainage (DVD). Follow up information was assessed 6 months after surgery in all but one patient, who died. The applied statistical test was chi2. RESULTS: Surgical morbidity was 15.3%. Early new deficits were noted in 39.3%, permanent new deficits in 10.6%, being significant (major) in 7.3%. The occurrence of permanent deficits correlated significantly with size, deep venous drainage, and the Spetzler-Martin scale. There was statistical evidence for a trend in risk of poor surgical outcome across the three categories non-eloquent, "less eloquent" (for example, visual cortex) and "highly eloquent" (brainstem, basal ganglia, or precentral cortex) with the last being associated with the highest risk for permanent neurological compromise. CONCLUSION: "Eloquence" of the Spetzler-Martin scale should be divided into "highly eloquent" and "less eloquent", which is important for risk analysis of the treatment of asymptomatic and deep seated AVMs and for future trials comparing various treatment modalities. In addition, resection of eloquent AVMs v non-eloquent ones is significantly associated with higher surgical morbidity.     

Spontaneous angiographic obliteration of cerebral arteriovenous malformations

OBJECTIVE: The factors associated with spontaneous angiographic obliteration of cerebral arteriovenous malformations (AVMs) are not well understood. We present a review of the literature and a report of our experience with six cases (four with no previous treatment intervention and two postoperative residual malformations) that were identified as having occurred during a 20-year period and describe the clinical and lesion features associated with this rare phenomenon. We present the first detailed histological study of a spontaneously thrombosed AVM specimen, including immunohistochemical analysis of angiogenesis factor expression. METHODS: A combined experience in the management of approximately 700 AVMs during 20 years identified six cases of spontaneous angiographic obliteration of cerebral AVMs. A literature review revealed another 24 cases with angiographic documentation of the initial AVMs and follow-up data showing nonfilling of the lesions. Histological analysis of a recently excised lesion included immunostaining with monoclonal antibodies to the antigens of Factor VIII, Tie, vascular endothelial growth factor, and its receptors, Flt-1 and Flk. RESULTS: A single draining vein was a feature in each of our 6 cases and in 12 of 14 (86%) cases from the literature. Hemorrhage as the presenting symptom was identified in 5 of our 6 (83%) cases and in 17 of 24 (71%) of the literature cases. The size of the AVM was less than 6 cm in each of our 6 cases and in 22 of 24 (92%) of the literature cases. A histological examination of a thrombosed AVM surgical specimen revealed persistent patent vascular channels within the lesion. Immunohistochemical analysis with angiogenesis and endothelia-specific factors showed expression of these factors within the lumen of the thrombosed nidus vessels. CONCLUSION: We propose that the occlusion of a single draining vein may lead to total venous outflow obstruction and lesion thrombosis. Hemorrhagic presentation and small nidus may also predispose to this phenomenon. Immunohistochemical analysis of a thrombosed AVM revealed possible ongoing angiogenic changes within the AVM vessels 1 month after angiographically documented thrombosis. It is possible that neovascularization within a thrombosed AVM may lead to lesion recanalization; however, this phenomenon seems to be clinically exceedingly rare.     

Semi-quantitative scintigraphic follow-up studies of cerebral arteriovenous malformations after radiosurgical treatment

An evaluation of semi-quantitative 99Tcm-red blood cell scintigraphy (RBCS) was undertaken in patients with cerebral arteriovenous malformations (AVM) during follow-up after radiosurgical treatment. Twenty-seven patients were studied with an initial dynamic imaging sequence of 32 frames each lasting 2 s, planar images in four projections beginning 15 min post-injection and single photon emission tomography immediately following the planar imaging. A 2 ml cubital vein blood sample was imaged to obtain an extracorporeal equivalent of the intravascular activity. The counts within the AVM on a planar image were divided by the counts obtained from the image of the blood sample (corrected for the same acquisition time and radioactive decay). This value yielded the 'volume index' (VI), which was proportional to the volume of the AVM. The VI obtained from the first RBCS served as the initial reference value and was set at 100%. The VIs obtained from the follow-up investigations of the same patient in the same projection were expressed as the percentage of the initial VI. We found RBCS identified the AVM in all patients. The VIs obtained from the follow-up studies demonstrated a decrease in blood volume at different time intervals after radiosurgical treatment. RBCS provides a sensitive, relatively non-invasive, semi-quantitative method for measuring the relative volume and follow-up of the degree of obliteration of AVMs after radiosurgical treatment.     

Alternative splicing of CYP2D mRNA in human breast tissue

Cerebrovascular arteriovenous malformations (AVMs) display abnormal vascular development and dysautoregulation of blood flow. Genetic mechanisms that contribute to the pathogenesis and phenotype of cerebral AVMs are unknown. As a first step in understanding the pathophysiology of AVMs, the authors investigated the hypothesis that endothelial dysfunction-specifically, deregulation of endothelin-1 (ET-1) secretion-contributes to the abnormal vascular phenotype and the lack of hemodynamic autoregulation elaborated by these lesions. Endothelin-1 peptide and preproendothelin-1 (ppET1) messenger RNA were not detected in the intranidal vasculature of all 17 patients with AVMs studied, but were prominently expressed in human control subjects with normal cerebrovasculature (p < 0.01). Although AVM vasculature lacked ET-1, its expression was prominent in vasculature distant from these lesions, suggesting local repression of the ppET-1 gene. Local repression of ET-1 was specific to AVMs; ET-1 in vascular malformations of patients with Sturge-Weber disease was actually elevated compared to normal controls (p < 0.01). Repression of the ppET-1 gene was an intrinsic phenotype of AVM endothelial cells and was not due to factors in the AVM microenvironment. The authors also showed that ETA receptor expression was low in AVM vasculature compared to normal controls. Together, these results demonstrate that the ppET-1 gene is locally repressed in AVM lesions and suggest a role for abnormal ppET-1 gene regulation in the pathogenesis and clinical sequelae of cerebral AVMs.     

Factors associated with successful arteriovenous malformation radiosurgery

OBJECTIVE: To analyze the clinical and angiographic variables that affect the results of arteriovenous malformation (AVM) radiosurgery and to propose a new method of reporting patient outcomes after AVM radiosurgery. This method incorporates both the obliteration status of the AVMs and the postoperative neurological condition of the patient. METHODS: Patient outcomes were defined as excellent (nidus obliteration and no new deficits), good (nidus obliteration with a new minor deficit), fair (nidus obliteration with a new major deficit), unchanged (incomplete nidus obliteration without a new deficit), poor (incomplete nidus obliteration with any new deficit), and dead. Two hundred twenty patients who underwent AVM radiosurgery at our center before 1992 were subjected to a multivariate analysis with patient outcomes as the dependent variable. RESULTS: Multivariate analysis determined four factors associated with successful AVM radiosurgery: smaller AVM volume (P=0.003), number of draining veins (P=0.001), younger patient age (P=0.0003), and hemispheric AVM location (P=0.002). Preradiosurgical embolization was a negative predictor of successful AVM radiosurgery (P=0.02). CONCLUSION: AVM obliteration without new neurological deficits can be achieved in at least 80% of patients with small volume, hemispheric AVMs after single-session AVM radiosurgery. Future studies on AVM radiosurgery should report patient outcomes in a fashion that incorporates all the factors involved in successful AVM radiosurgery.     

Interim report on the radiosurgical treatment of cerebral arteriovenous malformations. The influence of size, dose, time, and technical factors on obliteration rate

During the authors' initial 4-year experience with radiosurgery using the Leksell cobalt-60 gamma unit, they treated 121 patients with cerebral arteriovenous malformations (AVMs). The radiosurgical dose to the margin of the nidus was 20 Gy for lesions less than 2.0 cm in diameter (volume < or = 4.2 cm3); 18 Gy for malformations 2.1 to 3.0 cm in diameter (volume 4.2-14.1 cm3); and 16 Gy for malformations greater than 3.0 cm (volume > 14.1 cm3). Fifty-one patients underwent follow-up angiography between 1 and 3 years after treatment, and complete obliteration of the nidus was confirmed in 38 (74.5%) of these patients. Thirty-two (74.4%) of 43 AVMs with volumes of 10 cm3 or less and six (75%) of eight larger AVMs (volume 11-30 cm3) showed complete obliteration. Analysis of the time course of AVM nidus shrinkage and obliteration showed that most of the radiosurgically induced effect had occurred by 36 months after treatment. Retrospective analysis of the dose plans for 10 AVMs that were not obliterated by 36 months after gamma knife radiosurgery at the authors' institution (eight cases) or elsewhere (two cases) revealed that six AVMs had not been covered completely by the prescribed isodose. Six (5%) of the 121 patients developed neurological deficits as a direct result of radiosurgical treatment. The authors infer from these data that malformations up to 30 cm3 in volume (approximately 4.0 cm in average diameter) can be treated effectively with an acceptably low complication rate using a radiosurgical dose of 16 Gy to the margin of the nidus. The obliteration rate for the larger malformations that were treated with a dose of 16 to 18 Gy appears to be similar to that for smaller ones treated with 18 to 20 Gy. As more experience accrues using radiosurgery to treat AVMs, patient selection criteria and the variables associated with successful obliteration of the nidus should become more clearly defined.     

Utility of the American Diabetes Association risk test in a community screening program

In many patients with superficial siderosis of the central nervous system (CNS) no source of bleeding can be established, despite extensive examinations. The authors report a patient with superficial siderosis and a spinal arteriovenous malformation (AVM) that was not visible on magnetic resonance (MR) imaging or myelography but was identified on angiographic studies. This 71-year-old man presented with a 2-year history of progressive gait difficulties and hearing loss. Examination showed ataxia, hearing loss, and quadriparesis. On MR imaging superficial siderosis of the brain and spinal cord as seen; however, MR imaging of the CNS, as well as cerebral angiography and myelography studies, did not reveal the source of hemorrhage. Spinal angiography revealed a small slow-flow pial AVM at the C-5 level originating from the anterior spinal artery. A C-5 corpectomy was performed and the AVM was obliterated. The patient did well and reported no further progression of his symptoms during 3 months of follow up. Spinal angiography is indicated to complete the evaluation of patients with superficial siderosis, even if results of spinal MR imaging and myelography studies are normal. Obliteration of spinal AVMs may successfully prevent the progression of superficial siderosis.     

Hereditary neurocutaneous angiomatosis. Report of four cases

The authors report the coexistence of vascular nevi (hemangiomas and arteriovenous malformations (AVMs) of the skin) with AVMs and venous malformations of the brain in male siblings from two related but nonconsanguineous families of three generations. The proband, his siblings, parents, aunts, uncles, and cousins were examined, underwent magnetic resonance (MR) imaging and MR angiography, and when appropriate, cerebral angiography. A father had vascular nevi and a mother, his sister, had an azygos anterior cerebral artery. No other cutaneous or cerebrovascular malformations were present in the parents. Each of the two families had two boys and one girl, 9 to 18 years of age. All the children had vascular nevi and all of the boys had coexisting cerebrovascular malformations: AVMs in three, and a venous malformation in another. One boy had three cerebral AVMs. Two boys had a cerebral hemorrhage, and one also had focal motor seizures. The skin lesions were not those of the Sturge-Weber-Dimitri, Rendu-Osler-Weber, or Wybum-Mason syndromes. The association of cutaneous and cerebrovascular malformations was seen only in males in these families. but females have also been reported in the literature. The results obtained in these families and three other families reported from Western and Central Europe indicate that the association of cerebral and cutaneous vascular hamartomas constitutes a distinct, hereditary clinicopathological entity with autosomal dominant inheritance and variable penetrance. The clinical manifestations of this syndrome are visible, painful vascular nevi, epilepsy, cerebral hemorrhage, and focal neurological deficits. The preponderance of male patients with the full expression of the syndrome suggests a possible hormonal influence on the expression of the gene.     

Spontaneous disappearance of arteriovenous malformation during staged treatment of multiple cerebral arteriovenous malformations--case report

A 36-year-old male presented with aphasia and right hemiparesis due to the rupture of the larger of two arteriovenous malformations (AVMs) coexisting in the left hemisphere. The two AVMs had completely separate locations and different feeding arteries and draining systems. Two months after resection of the larger AVM and evacuation of the hematoma, carotid angiography showed the residual AVM had spontaneously disappeared. He was discharged without deficits. Change of cerebral hemodynamics after removal of the larger AVM presumably caused the spontaneous regression of the smaller one. Cerebral angiograms should be carefully examined because cerebral hemodynamics may be altered after removal of an AVM.     

Morbidity due to intracerebral hemorrhage

INTRODUCTION: Intracerebral hemorrhage (HIC) represents 10-30% of all stroke. Epidemiological studies have shown factors associated with its high mortality, but those which might lead to lower morbidity are little known. OBJECTIVE: To find the factors which may influence the functional state of a series of patients with intracerebral hemorrhage. PATIENTS AND METHODS: We made a prospective study of 203 patients with intracerebral hemorrhage. We recorded vascular risk factors, arterial blood pressure, laboratory and neuroimaging parameters obtained on admission. The functional condition when discharged from hospital was evaluated on the Rankin Scale, in three categories: independent (Rankin 0-1), partially dependent (Rankin 2-3) and totally dependent patients (Rankin 4-5). RESULTS: There was a 23.2% death rate. Of the 156 patients who survived, at the time of hospital discharge 35.8% had a score of 0-1, 50.6% a score of 2-3 and 13.4% a score of 4-5 on the Rankin Scale. Age (p < 0.005), hyperglycaemia (p < 0.05) and size of hemorrhage (p < 0.05) were associated with increased morbidity. CONCLUSIONS: The functional condition on hospital discharge was better in younger patients with lower levels of glycemia on admission and smaller hematomas on CT.     

Occurrence of severe vasospasm following intraventricular hemorrhage from an arteriovenous malformation. Report of two cases

The authors present two rare cases of severe cerebral vasospasm following the rupture of arteriovenous malformations (AVMs). Computerized tomography revealed intracerebral hemorrhage in the thalamus in one case and in the putamen in the other, both accompanied by cast formation of intraventricular clots without radiological evidence of subarachnoid hemorrhage. Initial angiograms showed arterial narrowing of the bilateral internal carotid arteries in the supraclinoid portion but failed to demonstrate an arteriovenous shunt. Subsequent angiograms clearly demonstrated the existence of an AVM. Radiological features and possible mechanisms are discussed.     

Successful surgical removal of a large arteriovenous malformation in a patient with hemophilia: case report

OBJECTIVE AND IMPORTANCE: This is the first reported case of the successful surgical removal of a large arteriovenous malformation (AVM) in a patient with hemophilia A. CLINICAL PRESENTATION: A 19-year-old male patient was admitted to our department with intracranial hemorrhage. He had previously been diagnosed with hemophilia A and a cerebral AVM. Carotid angiography revealed a large AVM in the right temporal and parietal lobes. The neurological and neuroradiological findings, especially those of single photon emission computed tomography, identified an area of devitalization around the lesion, which was thought to reduce the risk of new deficits resulting from surgical manipulation. INTERVENTION: We resected the AVM in conjunction with supplemental infusions of Factor VIII before, during, and after the operation. A slight cerebral hemorrhage on the 7th postoperative day was observed despite control with Factor VIII, but the patient was discharged without any new deficits. CONCLUSION: We evaluated and managed all problems of a patient with multiple complications and achieved a medical cure.     

Stereotactic radiosurgery for cavernous malformations: Kjellberg's experience with proton beam therapy in 98 cases at the Harvard Cyclotron

OBJECTIVE: The lack of treatment options for surgically inaccessible cavernous malformations has made radiosurgery a possible alternative to conservative management. The few previous reports of radiosurgical efficacy have been limited by small numbers, short follow-up, or lack of attention to the full spectrum of end points, including neurological disability. In an attempt to elucidate the risk-to-benefit ratio of radiosurgery for cavernous malformations, we undertook a retrospective analysis of of 95 patients with 98 lesions treated by the late Raymond N. Kjellberg. METHODS: Patients were followed for an average of 5.4 years (range, 0.3-12.3 yr), and data regarding hemorrhage, seizure, neurological disability, and incidence of radiation-induced complications were gathered. RESULTS: The analysis revealed a drop in annual hemorrhage rates from 17.3% per lesion per year before treatment to 4.5% per lesion per year after a latency period of 2 years. Improvement in seizure control was evident. However, a 16% incidence of permanent neurological deficit and a 3% mortality rate were attributable to radiographically confirmed radiation-induced complications. Neurological disability scores, measured by the modified Rankin disability scale, indicated a significant decline in neurological functioning during the follow-up interval, a result of the combined effects of radiation-related injury, hemorrhage, and clinical progression of the lesion. CONCLUSION: We conclude that although radiosurgery does seem to reduce hemorrhage, there is potential for complications and continued lesion progression after radiosurgery. These risks and benefits must be carefully balanced against the natural history of untreated lesions if the use of radiosurgery is considered.     

Avidity of IgG antibodies distinguishes primary from non-primary cytomegalovirus infection in pregnant women

OBJECTIVE: To define the epidemiology, risk factors, and unadjusted cost of hemorrhages related to cardiothoracic operations. STUDY DESIGN: We conducted two case-control studies to evaluate the risk of hemorrhage following cardiothoracic operations. The definition of hemorrhage required one of the following: reoperation for bleeding, postoperative loss of greater than 800 mL of blood over 4 hours, or surgeon-diagnosed excessive intraoperative bleeding. SETTING: The cardiothoracic surgery service of a university hospital. RESULTS: Of 511 patients undergoing cardiothoracic operations, 93 (18%) met the definition of hemorrhage. In the first case-control study, 3 (14%) of 21 cases and 0 of 42 controls died (odds ratio [OR], 15.0; 95% confidence interval [CI95], 1.18-191.55). Compared with controls, cases received significantly more packed red blood cells intraoperatively (OR, 1.18/100 mL; CI95, 1.01-1.38), and significantly more platelets (OR, 3.26/100 mL; CI95, 1.47-7.26) and fresh frozen plasma (OR, 1.73/100 mL; CI95, 1.05-.84) in the intensive-care unit. Cases were more likely than controls to receive protamine postoperatively (OR, 3.74; CI95, 1.27-11.02). Previous sternotomy, preoperative aspirin or heparin, and preoperative laboratory values did not predict bleeding. The median unadjusted hospital cost was $3,458 higher for patients who suffered hemorrhage than for controls. To decrease costs, hetastarch (acquisition cost $45/500 mL) was substituted for albumin (acquisition cost $76/100 mL) in the pump priming solution (estimated possible cost savings, $7,000-$53,000/year). Because hemorrhage rates increased subsequently, we conducted a second case-control study that identified patient age (P=.02) and use of greater than 5 mL/kg of hetastarch (OR, 1.82) as risk factors for hemorrhage. The cost of treating hemorrhages exceeded all estimates of possible cost savings ($7,000-$53,000 per year). CONCLUSIONS: Our definition of hemorrhage identified patients who required increased volumes of blood products and who had an increased crude mortality rate and a higher unadjusted cost of hospitalization. Patient age and hetastarch use were risk factors for hemorrhage. Efforts to save money by substituting less expensive products inadvertently may increase costs by increasing the probability of perioperative adverse events.     

Monitoring of cerebrospinal fluid pressure during embolization of AVM

We experienced that therapeutic embolization of a large cerebral arteriovenous malformation (AVM) led to venous outflow obstruction resulting in intracranial hypertension in a patient who had undergone external decompression. To evaluate hemodynamic changes after embolization, we monitored the cerebrospinal fluid pressure in the next four patients who underwent endovascular treatment. The embolization of a medium AVM resulted in a slight increase in the cerebrospinal fluid pressure. In two medium AVMs, embolization produced slight decreases in the cerebrospinal fluid pressure. In a small AVM, we did not observe any changes in the cerebrospinal fluid pressure during the endovascular treatment. We discuss the mechanism of changes in the intracranial pressure after embolization and conclude that monitoring of the cerebrospinal fluid pressure immediately yields useful information for hemodynamic changes during endovascular treatment.