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Biomedical subjects

R T Higashida

Publications and source records attributed to R T Higashida.

At least 91 records · Page 5Linked to original sources
PubMed1994

Development of acquired arteriovenous fistulas in rats due to venous hypertension.

Dural sinus thrombosis has been hypothesized as a possible cause of dural arteriovenous fistulas (AVF's). The pathogenesis and evolution from thrombosis to actual development of an AVF are still unknown. To study dural fistula formation, a surgically induced venous hypertension model in rats was created by producing an arteriovenous shunt between the carotid artery and the external jugular vein. The external jugular vein beyond the anastomosis was ligated 2 to 3 months after surgery and angiography was performed to identify any new acquired AVF's. Forty-six male Sprague-Dawley rats, each weighing approximately 300 gm, were used for this study. In Group I, 22 rats underwent a common carotid artery anastomosis to the external jugular vein, which is the largest draining vein from the transverse sinus via the posterior facial vein, followed by proximal external jugular vein ligation. In Group II, 13 rats underwent the same surgical procedure, followed by contralateral posterior facial vein occlusion. Group III served as the control group, in which 11 rats underwent only unilateral external jugular vein occlusion with or without contralateral posterior facial vein occlusion. The shunts in Groups I and II were ligated at 2 to 3 months following surgery, and transfemoral angiography was performed immediately before and after occlusion. New acquired AVF's had developed in three rats (13.6%) in Group I, three rats (23.1%) in Group II, and no rats (0%) in Group III. One of these newly formed fistulas was located at the dural sinus, analogous to the human dural AVF. The other five were located in the subcutaneous tissue, including the face and neck. The dural AVF in the rat was present on follow-up angiography at 1 week after the bypass occlusion. It is concluded that chronic venous hypertension of 2 to 3 months' duration, without associated venous or sinus thrombosis, can induce new AVF's affecting the dural sinuses or the subcutaneous tissue.

Animals↗
PubMed1994

Treatment of dural sinus thrombosis by urokinase infusion.

PURPOSE: To gain a preliminary understanding of the role of thrombolytic therapy for the thrombosed dural sinus, we retrospectively reviewed our initial experience. METHODS: Seven patients, ages 25 to 71, who presented with symptomatic dural sinus thrombosis and who failed a trial of medical therapy were treated with direct infusion of urokinase into the thrombosed sinus. Patients received urokinase doses ranging from 20,000 to 150,000 U/h with a mean infusion time of 163 hours (range 88 to 244 hours). RESULTS: Patency of the affected dural sinus was achieved with antegrade flow in all patients. Six patients either improved neurologically over their prethrombolysis state or were healthy after thrombolysis; one of them required angioplasty. The other patient improved after surgical repair of a residual dural arteriovenous fistula. The only complications were an infected femoral access site which resolved after treatment with antibiotics and hematuria which cleared after discontinuation of anticoagulation. CONCLUSIONS: Thrombolysis of the thrombosed dural sinus shows promise as a safe and efficacious treatment. The results of this study should provide the impetus for further research.

Adult↗
PubMed1994

Intracranial aneurysms. Evolution and future role of endovascular techniques.

Treatment of patients with an intracranial aneurysm by interventional neurovascular techniques has made tremendous advances over the past decade. Innovative occlusion devices have included detachable latex and silicone balloons, liquid polymers, intravascular lasers, and stents. As this technology continues to evolve, treatment options will expand and morbidity will continue to decline. The indications for treatment using minimally invasive surgical techniques will alter current management for these difficult and challenging vascular disorders.

Animals↗
PubMed1993

Treatment of giant intradural (perimedullary) arteriovenous fistulas.

Ten patients with giant intradural spinal arteriovenous fistulas (perimedullary Types II and III) were treated with embolization alone (three patients) or in combination with surgery (seven patients). Their ages at the time of treatment ranged from 2 to 40 years, with a mean of 19.5 years. The indications for treatment included progressive myelopathy in five patients, spinal subarachnoid hemorrhage in four, and acute paraplegia in one. Associated conditions included Rendu-Osler-Weber syndrome in two patients, and Cobb's syndrome in two patients. In one patient, the cause of the fistula may have been related to epidural anesthesia traumatizing a low tethered cord. Angiographically, the fistulas were subclassified in three groups: a single-hole fistula supplied by a single feeding medullary artery (three patients); a single-hole fistula supplied by multiple medullary arteries (three patients); and multiple separate fistulas supplied by multiple medullary arteries (four patients). Eight patients were classified as perimedullary Type III and two as perimedullary Type II. Embolic agents were delivered from transarterial routes in 14 procedures and transvenous routes in 2 procedures. A total of 16 embolizations and 8 operations were performed in 10 patients. Seven patients were cured of their fistula (as demonstrated by angiography), two patients had 5% residual filling and are scheduled for future therapy. One refused a follow-up angiographic examination. Complications related to embolization included rupture of the anterior spinal artery by a detachable balloon, resulting in transient worsening of paraplegia with recovery to baseline. Transient worsening of symptoms after surgery was common, but all patients returned to baseline or better. Dramatic improvement was observed in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Transluminal angioplasty for atherosclerotic disease of the vertebral and basilar arteries.

Transluminal angioplasty for hemodynamically significant stenosis (> 70%) involving the posterior cerebral circulation is now being performed by the authors in selected cases. A total of 42 lesions affecting the vertebral or basilar artery have been successfully treated by percutaneous transluminal angioplasty techniques in 41 patients. The lesions involved the proximal vertebral artery in 34 cases, the distal vertebral artery in five, and the basilar artery in three. Patients were examined clinically at 1 to 3 and 6 to 12 months after angioplasty. Three (7.1%) permanent complications occurred, consisting of stroke in two cases and vessel rupture in one. There were four (9.5%) transient complications (< 30 minutes): two cases of vessel spasm and two of cerebral ischemia. Clinical follow-up examination demonstrated improvement of symptoms in 39 cases (92.9%). Radiographic follow-up studies demonstrated three cases (7.1%) of restenosis involving the proximal vertebral artery; two were treated by repeat angioplasty without complication, and the third is being followed clinically while the patient remains asymptomatic. In patients with significant atherosclerotic stenosis involving the vertebral or basilar artery territories, transluminal angioplasty may be of significant benefit in alleviating symptoms and improving blood flow to the posterior cerebral circulation.

Adult↗
PubMed1993

Endovascular treatment of vertebral artery dissections and pseudoaneurysms.

Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.

Adult↗
PubMed1992

Intravascular balloon dilatation therapy for intracranial arterial vasospasm: patient selection, technique, and clinical results.

Patients presenting with symptomatic intracranial arterial vasospasm are now being treated by interventional neurovascular techniques in selected cases. From a percutaneous transfemoral approach, a custom-designed silicone microballoon can be guided through the intracranial vessels, and inflated to dilate the spastic vessel(s). This technique has been useful for both focal and diffuse areas of spasm. In clinical trials, 28 patients, ranging in age from 15-73 years have been treated. A total of 99 vascular territories have been successfully dilated in both the anterior and posterior circulations. Clinical improvement following treatment was observed in 17 cases (60.7%). Technical complications directly related to therapy included 2 cases (7.1%) of vessel rupture. In long term clinical follow-up 17 patients (60.7%) had good to excellent outcome, 2 patients (7.1%) remained in poor condition, and 9 patients (32.1%) died despite therapy. In patients presenting with symptomatic intracranial arterial vasospasm who are unresponsive to medical therapy, treatment by balloon angioplasty techniques may help to improve cerebral perfusion and clinical outcome of the patient.

Adolescent↗
PubMed1991

Interventional neurovascular treatment of a giant intracranial aneurysm using platinum microcoils.

A 70-year-old woman presented with symptoms of progressive cerebellar dysfunction due to mass effect from a giant, expanding, posterior fossa aneurysm arising from the distal vertebral artery. The aneurysm contained thrombus and had a broad-based neck. From a transfemoral approach, with the patient under local anesthesia, a 2.2 French microcatheter was guided through the vertebral artery and placed directly into the aneurysm. Six 5 x 15-mm platinum microcoils were deposited into the residual lumen of the aneurysm, resulting in complete thrombosis with obliteration of the aneurysm and preservation of the parent artery. Endovascular coil embolization therapy by interventional neurovascular techniques may provide a therapeutic alternative in the management of surgically difficult symptomatic intracranial aneurysms.

Aged↗
PubMed1991

Direct endovascular thrombolytic therapy for dural sinus thrombosis.

Three patients, ages 51 to 71 years, sought treatment for symptomatic dural sinus thrombosis with occlusion and were treated by direct sinus perfusion with urokinase. All three patients had a dural arteriovenous fistula; one involved the inferior petrosal sinus and two involved the transverse sinus. Clinical findings included papilledema, diminished visual acuity, decreased mentation, and cranial nerve palsies. Diagnosis was made by cerebral arteriography and confirmed by sinus venography. All three patients were treated by a transjugular direct infusion of urokinase. In one patient, a transfemoral venous approach used initially was discontinued because of an infection. The period of continuous infusion for thrombolysis ranged between 4 and 10 days. In two patients, the clinical signs and symptoms improved with angiographic evidence of clot lysis and dural sinus recanalization. Angiography indicated that one patient had a partial resolution of a clot in the torcular herophili and transverse sinus but showed no clinical improvement. These preliminary results suggest that transjugular local infusion of thrombolytic agents can be an effective treatment for symptomatic, thrombosed dural sinuses. This selective lysis avoids thrombolytic effects that could aggravate or produce systemic hemorrhagic complications.

Aged↗
PubMed1991

Intracranial aneurysms: interventional neurovascular treatment with detachable balloons--results in 215 cases.

Patients with complex or surgically difficult intracranial aneurysms are being treated with interventional neurovascular techniques. With neuroleptic anesthesia and a transfemoral femoral approach, a silicone micro-balloon can be flow directed through the intracranial circulation, guided directly into the aneurysm, and detached. The aneurysm is thus eliminated from the circulation, and the parent artery is preserved. For broad-based or ectatic aneurysms, test occlusion followed by permanent occlusion of the aneurysm and parent vessel can be performed. Since 1981, 211 patients with 215 aneurysms, including 177 cases involving the anterior and 38 cases involving the posterior circulation, have been treated with this technique. In 127 cases (59.1%), the parent vessel was occluded; in 88 cases (40.9%), primary occlusion of the aneurysm was achieved with preservation of the parent artery. Therapy-related complications included 21 deaths (9.8%) and 16 strokes (7.4%). Follow-up examinations were performed at 1, 3, and 12 months after treatment, and follow-up ranged from 5 months to 9 years. In patients in whom standard surgical therapy fails or for aneurysms in surgically inaccessible anatomic locations, interventional techniques that make use of detachable balloons may be a useful therapeutic alternative.

Adult↗
PubMed1991

A variant of arteriovenous fistulas within the wall of dural sinuses. Results of combined surgical and endovascular therapy.

Dural arteriovenous (AV) fistulas are thought to be acquired lesions that form in an area of thrombosis within a sinus. If the sinus remains completely thrombosed, venous drainage from these lesions occurs through cortical veins, or, if the sinus is open, venous drainage is usually into the involved sinus. Among 105 patients with dural AV fistulas evaluated over the the past 5 years, seven had a unique type of dural AV fistula in the superior sagittal, transverse, or straight sinus in which only cortical venous drainage occurred despite a patent involved sinus; the fistula was located within the wall of a patent dural sinus, but outflow was not into the involved sinus. This variant of dural AV fistulas puts the patient at serious risk for hemorrhage or neurological dysfunction caused by venous hypertension. Three patients presented with hemorrhage, one with progressive neurological dysfunction, one with seizures, and two with bruit and headaches. A combination of surgical and endovascular techniques was used to close the fistula while preserving flow through the sinus.

Adult↗
PubMed1991

Advances in the treatment of complex cerebrovascular disorders by interventional neurovascular techniques.

Treatment of complex cerebrovascular disorders, including intracranial aneurysms, carotid cavernous sinus fistulas, vertebral fistulas, arteriovenous malformations, atherosclerosis of brachiocephalic vessels, and arterial vasospasm, is being performed in selected cases by interventional neurovascular techniques. Recent advances in microballoon technology, permanent solidifying polymers, newer embolic agents, high-resolution digital subtraction angiography with road-mapping technique, and steerable micro-guide wires and catheters have greatly improved access in the distal intracranial circulation and markedly reduced the morbidity associated with these procedures. Interventional neuroradiology is emerging as an important adjunct to neurosurgery for selected cerebrovascular disorders.

Angioplasty, Balloon↗
PubMed1990

Dural arteriovenous fistulas supplied by ethmoidal arteries.

Eight patients with dural arteriovenous fistulas (DAVFs) located on the floor of the anterior cranial fossa and supplied by enlarged ethmoidal branches of the ophthalmic artery are described. Five patients showed the classical symptom of intracerebral hemorrhage (all five had ipsilateral frontal lobe hematomas and one also had an associated a subdural hematoma). Two patients exhibited atypical symptoms of proptosis, chemosis, elevated intraocular pressure, and loss of vision secondary to an ethmoidal DAVF, which drained posteriorly to the cavernous sinus. The eighth patient exhibited proptosis and chemosis secondary to a cavernous sinus DAVF and was incidentally found to have an asymptomatic ethmoidal DAVF. One additional patient had two separate dural fistulas: one located on the cribriform plate and the second located in the posterior fossa. Seven of the eight patients were cured by surgical excision of the fistula site; in the remaining patient spontaneous obliteration followed a surgical procedure for a cavernous DAVF. DAVFs involving the floor of the anterior cranial fossa usually present with hemorrhage, but can present with ocular symptoms or be entirely asymptomatic and are effectively treated by surgical excision of the fistula site.

Aged↗
PubMed1990

Treatment of carotid-cavernous fistulas associated with Ehlers-Danlos syndrome.

Four patients with Ehlers-Danlos syndrome presented spontaneously with symptomatic direct carotid-cavernous fistulas. Two had previously (2 and 15 years, respectively) had contralateral carotid-cavernous fistulas that were treated with carotid occlusion procedures. The patients' ages at presentation ranged from 19 to 49 years, with a mean of 32 years. All four patients underwent attempted embolization procedures. Two patients had transarterial embolization, one with balloons and liquid adhesives, one with platinum coils and a balloon; the carotid artery was preserved in one and sacrificed in one other. In one patient, who underwent direct puncture of the carotid artery, a massive hematoma causing airway compromise required intubation and emergent surgical repair. The fistula spontaneously closed during this event. In the fourth patient, two transvenous embolizations resulted in markedly decreased flow, but diversion of residual flow to cortical veins produced a fatal pontine hemorrhage. The vascular fragility associated with Ehlers-Danlos syndrome can produce spontaneous direct carotid-cavernous fistulas and makes both diagnostic and therapeutic procedures more difficult.

Adult↗
PubMed1990

Interventional neuroradiological management of vein of Galen malformations in the neonate.

Since 1978, the authors have seen 14 neonates with vein of Galen malformations who were born with severe congestive heart failure. The 5 infants treated before 1983 underwent craniotomy and clipping of feeding vessels; all died in the perioperative period. Since 1983, 8 neonates have been treated with combined arterial and venous interventional neuroradiological techniques; 6 infants survived. Two-dimensional echocardiography, color Doppler flow imaging, and pulsed Doppler ultrasound were used to assess blood flow within the malformation before and after staged transluminal embolic procedures were performed. The results of the diagnostic studies and the clinical status of the infants were used to evaluate the success of embolic therapy and the need for further neuroradiological intervention.

Cerebral Veins↗
PubMed1990

Serial ultrasonographic evaluation of neonatal vein of Galen malformations to assess the efficacy of interventional neuroradiological procedures.

Two-dimensional echocardiography complemented with color-flow imaging and pulsed Doppler ultrasound was used to evaluate one fetus and five neonates with a vein of Galen malformation who had severe high-output congestive heart failure and cranial bruits at birth. Intracranial blood flow through the vein of Galen malformations, cardiac status, and direction of aortic blood flow were assessed before and after staged interventional neuroradiological treatment with transarterial and transvenous embolization procedures. Color-flow imaging in each infant displayed the major vascular anatomy including feeding vessels and the patterns of filling of the vein of Galen malformations. Pulsed Doppler ultrasound performed on the descending aorta above the diaphragm showed the degree of diastolic flow reversal indicative of runoff into the vein of Galen malformations. A reduction in blood flow through the vein of Galen malformation was seen on color-flow imaging in four patients treated successfully by embolic procedures. The ratio of diastolic retrograde flow velocity in the descending aorta to systolic antegrade velocity decreased from 0.51 +/- 0.15 (mean +/- standard deviation) to 0.15 +/- 0.20 (P less than 0.05). Color-flow imaging and pulsed Doppler ultrasonography provided anatomical and pathophysiological information regarding cardiac hemodynamics and intracranial blood flow; with the patient's clinical status, these methods provided a reliable, noninvasive means to evaluate the effectiveness of therapy and the need for further treatment in neonates with vein of Galen malformations.

Cerebral Veins↗