Hiroo Yamaga

Results of endovascular treatment of internal carotid artery stenoses with a newly developed balloon protection catheter.

OBJECTIVEA new balloon protection catheter to prevent distal emboli during internal carotid artery percutaneous transluminal angioplasty and stenting was developed, and its efficacy was evaluated in both an experimental model and clinical cases. METHODSThe balloon protection catheter was navigated over a steerable 0.014-inch guidewire to negotiate tight stenoses and sharp bends, which would cause difficulties for the passage of a flow-directed balloon catheter. Percutaneous transluminal angioplasty and stenting were performed for 85 consecutive patients with 87 stenotic lesions of the cervical internal carotid artery, with two different methods using this protection system. Distal protection was provided only after dilation for the initial 38 lesions (Group I), but the latter 49 lesions were treated in both the pre- and postdilation periods (Group II). The effects of using the balloon protection catheter with the embolic debris clearance technique were evaluated with pre- and postoperative magnetic resonance imaging for each group. RESULTSThe balloon protection catheter was introduced beyond the stenosis in all cases. In Group I, one symptomatic embolic stroke was caused by distal embolization resulting from atheromatous plaque, and high-intensity areas appeared on diffusion-weighted magnetic resonance imaging scans in 47% of cases. In contrast, in Group II, there were no strokes related to the procedure, although one patient with multiple risk factors died suddenly on the second day after stenting. Diffusion-weighted imaging scans demonstrated small, high-intensity areas in 19% of cases in Group II. The overall morbidity/mortality rate in our series was 2.3%. CONCLUSIONOur new balloon protection catheter was reliably navigated across internal carotid artery stenoses and reduced distal embolism in clinical cases.

Endovascular treatment for pseudo-occlusion of the internal carotid artery.

OBJECTIVE:The surgical benefit to pseudo-occlusion of the internal carotid artery (ICA) is controversial. Because the benefit of carotid endarterectomy for pseudo-occlusion of the ICA remains uncertain, we examined the use of carotid stenting as a possible alternative treatment for this condition. METHODS:Twenty cases of carotid pseudo-occlusion (17 symptomatic, three asymptomatic) were treated with carotid artery stenting. Nineteen patients were treated with various embolic protection techniques. Our clinical results, including angiographic follow-up data, perioperative complications, and data on the effectiveness of the embolic protection methods were studied for ICA pseudo-occlusion. RESULTS:All pseudo-occlusions were successfully dilated, and the stenotic ratio was reduced from 95 to 6.7% on average. No neurological deterioration was encountered in any of the cases, although one patient died of cardiac event 1 day after treatment. None of the patients experienced stroke during the mean 24.8 month follow-up period, although one patient died from myocardial infarction. Among the 17 cases in which follow-up angiography was performed at 6 months after stenting, only one patient demonstrated restenosis. This patient was successfully treated with repeated percutaneous transluminal angioplasty. The rate of restenosis in our series was 5.9%, and the morbidity/mortality rate within 30 days was 5%. CONCLUSION:The clinical results of carotid stenting for ICA pseudo-occlusion under embolic protection were fairly good from the viewpoints of periprocedural neurological morbidity, angiographic follow-up results, and stroke prevention. Carotid stenting can be considered an alternative to carotid endarterectomy in patients with ICA pseudo-occlusion.

Hemorrhagic complications after endovascular therapy for atherosclerotic intracranial arterial stenoses.

OBJECTIVE:Hemorrhagic complications were analyzed in 106 procedures of 99 patients treated with percutaneous transluminal angioplasty (PTA) or stenting for intracranial arterial stenoses. METHODS:Ninety-nine patients with intracranial arterial stenosis were treated with PTA or stenting 106 times from January 1995 to December 2003. Fifty-seven patients had intracranial internal carotid artery stenosis, 23 had middle cerebral artery stenosis, and 19 had vertebrobasilar stenosis. Evaluation of hemodynamic compromise via single-photon emission computed tomography was performed 50 times for 50 patients before the treatment. RESULTS:Four hemorrhagic complications occurred in 106 procedures. Two of these cases involved intracerebral hemorrhage after PTA or stenting in the treated vascular territory 30 minutes and 16 hours after the treatment, respectively. One case showed subarachnoid hemorrhage, which appeared 6 hours after treatment. Hemodynamic compromise was found on single-photon emission computed tomography in these three cases. The last case with a hemorrhagic complication was a hemorrhagic infarction after recanalization of stent thrombosis, which appeared 3 days after stenting. Hyperperfusion syndrome was strongly suggested as the cause of hemorrhage in the two cases associated with intracerebral hemorrhage. CONCLUSION:The rate of hemorrhagic complication directly related to the procedure of PTA or stenting was 3%, and hyperperfusion syndrome was suggested as the cause of hemorrhage in two cases (2%), from the perspective of clinical characteristics and single-photon emission computed tomographic findings.

Memory impairment and spatial disorientation following a left retrosplenial lesion.

We treated a patient in whom a left retrosplenial lesion resulted in memory impairment and spatial disorientation. A 31 year old, right handed man was admitted to our hospital after the sudden onset of headache. He was alert, attentive and cooperative, and showed no motor or sensory deficits. Although intelligence was preserved, memory was obviously deficient. The patient proceeded in wrong directions after he left his hospital room and subsequently his home. Neuroimaging revealed a subcortical hematoma in the left cingulate isthmus, while single-photon emission computed tomography demonstrated decreased perfusion in the splenium and left parietal lobe.

Endovascular recanalization of the completely occluded internal carotid artery using a flow reversal system at the subacute to chronic stage.

OBJECT The efficacy and pitfalls of endovascular recanalization were evaluated in cases of internal carotid artery (ICA) occlusion in the subacute to chronic stage. METHODS Fourteen cases (15 lesions) of symptomatic ICA occlusion with hemodynamic compromise or recurrent symptoms were treated at the subacute to chronic stage using an endovascular technique. The Parodi embolic protection system was used during the recanalization procedure to prevent embolic stroke by reversing the flow from the distal ICA to the common carotid artery. RESULTS Recanalization of the occluded ICA was possible in 14 of 15 lesions. The occlusion points were 10 cervical ICAs and 4 petrous/cavernous ICAs in successfully recanalized cases. Ischemic symptoms disappeared completely after the treatment, and new ischemic symptoms did not appear related to the treated lesion. Single photon emission computed tomography findings demonstrated the improvement of hemodynamic compromise in all cases. One case showed right middle cerebral artery branch occlusion during the procedure, but this patients neurological symptoms were stable due to preexisting hemiparesis. Endovascular recanalization was possible and effective in improving hemodynamic compromise. However, there are still several problems with this technique, such as hyperperfusion syndrome after recanalization, cerebral embolism during treatment, durability after treatment, and identification of the occlusion point before treatment. CONCLUSIONS Endovascular recanalization using an embolic protection device can be considered as an alternative treatment for symptomatic ICA occlusion with hemodynamic compromise or refractoriness to antiplatelet therapy, even in the subacute to chronic stage of the illness.

Carotid artery stenting for stenosis with intraluminal thrombus

Since intraluminal thrombus in the context of carotid artery stenosis is rarely encountered, treatment for this condition remains controversial. The present paper describes six cases of carotid artery stenosis with thrombus and discusses the efficacy and complications of carotid artery stenting (CAS). From April 2002 to May 2004, six patients with carotid artery stenosis and intraluminal thrombus receiving medical therapy underwent CAS at our institution. CAS was performed with distal protection alone (method 1) in three patients, and three other patients underwent CAS with reversed-flow system and distal protection (method 2). Two of six patients experienced worsening neurologic symptoms despite medical therapy. All six patients were successfully treated with CAS and showed satisfactory patency of the artery. Embolic lesions were detected on diffusion-weighted MRI after the procedure in all patients treated with method 1 but not in patients treated with method 2. Complications included stent thrombosis (n=1) and in-stent thrombus (n=1). All six patients achieved a modified Rankin Scale 1 or 2 classification at 30 days after stenting. In conclusion, CAS was feasible for stenosis even with intraluminal thrombus. Use of method 2 for this condition may reduce the incidence of thromboembolic events although our series was small in number.

Endovascular treatment of unruptured cerebral aneurysms

76 consecutive patients with 78 unruptured cerebral aneurysms underwent endovascular therapy from July 1999 to May 2004 in our institute. For the wide-necked aneurysms, the remodeling technique, double microcatheter technique, or stent-assisted coil embolization was used, while a parent artery occlusion or covered stent was applied for the giant or fusiform aneurysms. Immediate angiographical results demonstrated 33 complete occlusions, 26 neck remnants, and 14 dome fillings. Four cases were treated with parent occlusion or stenting only, and one case was not treated with embolization but with clipping due to the rupture of the aneurysm during coil embolization. Immediate angiographic findings demonstrated that in aneurysms between 5 to 10 mm, the rate of complete occlusion was 48%, that of neck remnants 33%, and that of dome fillings 27%. In aneurysms between 11 to 25 mm, the rate of complete occlusion was 14%, that of neck remnants 28%, and that of dome fillings was 58%. In the angiographic follow-up results, all aneurysms smaller than 5 mm showed complete occlusion. In aneurysms between 5 to 10 mm, 74% of the aneurysms showed complete occlusion, and 21% showed neck remnants, and 5% showed dome filling. In aneurysms between 10 to 24 mm, 25% showed complete occlusion, while 75% showed dome filling. The overall mortality rate was 0% and the morbidity rate was 3.7% (2 major strokes, 1 minor stroke) at 30-days after embolization. In the clinical follow-up study, one case of a large basilar tip aneurysm caused a fatal rupture 28 months after the initial embolization. Endovascular therapy was performed on the unruptured aneurysms and was found to be an acceptable treatment, except for durability in cases of large aneurysms.

Transcortical sensory aphasia due to a left frontal subcortical haemorrhage.

A case of transcortical sensory aphasia caused by a cerebral haemorrhage in the left frontal lobe is presented. A 72-year-old right-handed woman was admitted to the hospital, with a history of acute onset of speech disturbance and headache. On initial assessment, her spontaneous speech was fluent. She had no difficulty initiating speech, articulated normally, and did not exhibit logorrhea. Her ability to repeat phonemes and short sentences (5-6 words) was fully preserved, however she had severe difficulty with visual recognition of words, and with aural comprehension at the word level, although she was able to read words aloud. Computed tomography and magnetic resonance imaging showed cerebral haemorrhage in the left frontal lobe, involving the superior and middle frontal gyrus. Single photon emission CT revealed a wider area of low perfusion over the entire left frontal lobe, including the superior, middle and inferior frontal gyrus. The aphasia symptoms, mainly poor comprehension, disappeared quickly several weeks after the event. This may have been due to a reduction in the size of the haematoma and a resolution of the oedema around the haematoma. Clinically, the transcortical sensory aphasia in this case was indistinguishable from that caused by damage to the posterior language areas. Further case reports of transcortical sensory aphasia associated with frontal lobe lesions would help to confirm whether a relatively rapid recovery is characteristic in cases such as this.

Traumatic Bilateral Common Carotid Artery Dissection Due to Strangulation: A Case Report

We report a case of bilateral common carotid artery dissection due to strangulation successfully treated by stent placement, with a review of the literature. A 61-year-old woman was strangled by an apron strap. She was admitted to our hospital with tetraparesis, because of spinal cord injury. On the next day, her left hemiparesis aggravated and left facial palsy newly appeared. Diffusion weighted magnetic resonance imaging (MRI) showed new ischemic lesions in the right cerebral hemisphere. Aortography revealed bilateral common carotid artery dissection. Moreover, thrombus or intimal flap was recognized in the right common carotid artery. The right common carotid dissection was fixed with deployment of self expanding stents to prevent the aggravation of ischemic stroke at that time. The contralateral lesion was also treated ten days later because small ischemic lesions were newly recognized in the left hemisphere on MRI. No new neurological deficit appeared after bilateral carotid artery stenting. Her paraparesis completely improved two months after the spinal cord injury. Carotid artery stenting using self expanding stents was especially effective as the treatment for bilateral carotid artery dissection.

Transcortical mixed aphasia due to cerebral infarction in left inferior frontal lobe and temporo-parietal lobe

Abstract. We present a case of transcortical mixed aphasia caused by a cerebral embolism. A 77-year-old right-handed man was admitted to our hospital with speech disturbance and a right hemianopia. His spontaneous speech was remarkably reduced, and object naming, word fluency, comprehension, reading and writing were all severely disturbed. However, repetition of phonemes and sentences and reading aloud were fully preserved. Although magnetic resonance imaging (MRI) showed cerebral infarcts in the left frontal and parieto-occipital lobe which included the inferior frontal gyrus and angular gyrus, single photon emission CT revealed a wider area of low perfusion over the entire left hemisphere except for part of the left perisylvian language areas. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. Hence, it appears that transcortical mixed aphasia may be caused by the isolation of perisylvian speech areas, even if there is a lesion in the inferior frontal gyrus, due to disconnection from surrounding areas.