Masanari Onizuka

Retrospective analysis of neurological outcome after intra-arterial thrombolysis in basilar artery occlusion

BACKGROUND Basilar artery occlusion usually has a very poor outcome and is associated with a high mortality rate. Local intra-arterial thrombolysis may improve the clinical outcome and reduce mortality in the treatment of acute basilar artery occlusion. We evaluated the possible variables affecting recanalization and clinical outcome in patients with basilar artery occlusions undergoing thrombolytic therapy. METHODS We analyzed retrospectively the clinical course and outcome of a series of 26 patients between 1998 and 2001. All patients who were examined within 24 hours after onset of symptoms underwent emergency cerebral angiography and subsequent intra-arterial thrombolysis. Three patients additionally received percutaneous transluminal angioplasty of underlying stenosis at the site of thrombosis. RESULTS Outcome was good in 9 patients (34.6%) and poor in 17 (65.4%). Recanalization could be achieved in 24 patients (92.3%) and was not affected by age, sex, site of occlusion, etiology, thrombolytic drugs, or time interval. Good outcome was associated with younger age, good initial clinical condition, and no evidence of brain stem infarction. There was no association between the interval (greater or less than 6 hours) from the onset of symptoms until the end of thrombolysis and survival. CONCLUSIONS We confirm that intra-arterial thrombolysis reduces mortality in basilar artery occlusion. Young patients (<75 years) without any infarct in brain stem before the start of treatment seem to be the ideal candidates for thrombolysis. Basilar artery thrombosis could and should be reopened, even late (after 6 hours) after symptom onset.

Intraprocedural plaque protrusion resulting in cerebral embolism during carotid angioplasty with stenting

An 82-year-old man with an asymptomatic left high-grade carotid stenosis was treated with carotid artery stenting (CAS) under distal protection. The procedure consisted with predilation with a 5 × 40 mm percutaneous transluminal angioplasty (PTA) balloon, deployment of a 10 × 20 mm self-expandable stent, post-dilation with a 7 × 20 mm PTA balloon, and aspiration of debris with 60 ml of blood. The cervical carotid angiogram immediately after deflation of the distal blocking balloon demonstrated a small in-stent filling defect of the contrast medium that protruded from the anterior wall of the carotid artery. The following cranial carotid angiogram showed abrupt occlusion of the left middle cerebral artery (MCA). Because the in-stent lesion had vanished in the repeat study after recognition of this embolic event, it was suggested that an embolus had been liberated from the in-stent lesion, reaching the left MCA and obliterating it. In this case, the embolus was speculated to originate in the ruptured plaque, which protruded into the stent through the cells of the device and became liberated into the bloodstream. Attention should be paid so as not to overlook any plaque protrusion, which may be seen subsequently as a cerebral embolism on the angiogram obtained immediately after CAS.

Carotid Artery Stenting for Calcified Lesions

BACKGROUND AND PURPOSE: Our aim was to assess the feasibility of carotid artery stent placement (CAS) for calcified lesions. MATERIALS AND METHODS: Using embolic protection devices (EPDs), we performed 51 CAS procedures in 43 patients with severe carotid artery stenosis accompanied by plaque calcification. Before intervention, all lesions were subjected to multidetector-row CT. The arc of the circumferential plaque calcification was measured on axial source images at the site of maximal luminal stenosis, and the total volume of the plaque calcification was determined. The angiographic outcome immediately after CAS, and intra- and postoperative complications were recorded. RESULTS: The mean arc of calcification was 201.1 ± 72.3° (range, 76–352°), and the mean of the total calcification volume was 154.9 ± 35.4 mm3 (range, 92–2680 mm3). Balloon rupture occurred in 1 procedure (2.0%) at predilation angioplasty; all 51 CAS procedures were successful without clinical adverse effects. Although there was a correlation between the arc of plaque calcification and residual stenosis (r = 0.6, P < .001), excellent dilation with residual stenosis ≤30% was achieved in all lesions. There was no correlation between the total volume of calcification and residual stenosis. None of the patients developed stroke or death within 30 days of the CAS procedure. CONCLUSION: CAS by using EPDs to treat lesions with plaque calcification is feasible even in patients with near-total circumferential plaque calcification.

Accordion effect during carotid artery stenting: report of two cases and review of the literature.

IntroductionThe term “accordion effect” is used to describe a mechanical distortion of tortuous arteries mimicking spasm or dissection. This phenomenon has been reported in patients undergoing percutaneous coronary intervention. To our knowledge, this is the first documentation of the accordion effect during carotid artery intervention.MethodsTwo patients who developed the accordion effect during carotid artery stenting (CAS) are described.ResultsAngiograms obtained just after CAS showed a stenosing lesion with wall irregularity at the distal part of the stent. This lesion disappeared and tortuosity of the internal carotid artery developed after withdrawing the guidewire until its floppy segment rested equally on the lesion. In another patient, the lesion did not disappear completely until the guiding catheter had been withdrawn to the proximal portion of the common carotid artery. We conclude that these stenosing lesions reflected the accordion effect.ConclusionIt is essential to differentiate the accordion effect from dissection, spasm, and thrombosis because the management is importantly different. We report our findings and present a review of the literature.

Characteristics of symptomatic chronic subdural haematomas on high-field MRI

Abstract We studied the frequency of various features of the appearances on high-field MRI in symptomatic patients with chronic subdural haematomas (CSDH). The ability to predict recurrence after treatment with one burr-hole procedure using MRI was evaluated. A total of 40 patients with symptomatic CSDH underwent MRI at 1.5 T. All haematomas were evacuated within a few days of the MRI examination. Symptomatic CSDH were divided into five groups according to the MRI findings: group A (11 cases), isointense or low signal on T1- and low signal on T2-weighted images; group B (18 cases), high signal on T1- and low signal on T2-weighted images; group C (5 cases), high signal on both T1- and T2-weighting; group D (1 case), low signal on T1- and high signal on T2-weighted images; group E (5 cases), heterogeneous intensity on T1- and T2-weighting throughout the haematoma cavity. The mean interval between onset of symptoms and MRI for group A was 5.0 ± 4.1 days, which was significantly shorter than that for group B (9.4 ± 4.4 days, P < 0.02), group C (27.8 ± 20 days, P < 0.005) or group E (17.8 ± 12.2 days, P < 0.01). Recurrence was seen in three haematomas of group A and one of group B. Reoperation was most closely correlated with diffuse low signal on T2-weighted images but not with a multiloculated appearance. Low signal on T2 weighting was surprisingly high (72.5 %) and the age of the haematomas as estimated on the MRI correlated well with the interval between the onset of symptoms and MRI. Our findings support the causative role of recurrent bleeding in the enlargement of CSDH.

Spasm induced by protection balloon during carotid artery stenting

PurposeThe PercuSurge system is a distal balloon embolic protection device used for carotid artery stenting (CAS). We performed a retrospective study on the prognosis and clinical effects of spasms induced by the PercuSurge GuardWire system (PercuSurge-induced spasm).Materials and methodsWe performed CAS in 118 carotid stenoses using the PercuSurge system. Of the 118 procedures, 31 (26.3%) of the patients experienced PercuSurge-induced spasm, and all underwent postoperative follow-up studies by cerebral angiography and antiplatelet treatment.ResultsOn follow-up angiograms obtained a mean of 5.2 months (range 3–10 months) after CAS, all 31 PercuSurge-induced spasms had disappeared, and no delayed stenosis was found at the sites where the spasms had occurred. No ischemic events due to the spasms occurred during a mean follow-up of 13 months (range 3–32 months).ConclusionIn the hands of physicians experienced in endovascular surgery, CAS using the PercuSurge system is a safe method with which to treat patients with carotid stenosis. Our study demonstrated that PercuSurge-induced spasms had no morphological or clinical adverse effects.

Factors affecting rapid growth of unruptured cerebral aneurysms during the acute stage of subarachnoid hemorrhage.

Abstract Background and purpose: Several unruptured cerebral aneurysms have been reported to grow and rupture. To determine which factors affect the growth of these aneurysms during the acute stage of subarachnoid hemorrhage (SAH), a retrospective review was performed. Methods: Between January 2000 and January 2003, 130 patients with angiographically proven ruptured cerebral aneurysms were treated at our institution. Of these patients, 32 also had simultaneous unruptured aneurysms, and the total number of the unruptured aneurysms was 40, including two neck remnants which had remained since the past clipping. Seventeen patients had 17 unruptured aneurysms and two neck remnants. The unruptured aneurysms were not treated during the acute stage of SAH but had received a complete short term follow-up. Results: The rapid growth of one unruptured aneurysm and two neck remnants was confirmed by a second angiogram performed on average40 days after the first angiogram. Several candidate factors responsible for the growth of aneurysm were selected, and the results of a statistical analysis indicate that a systolic blood pressure above 200 mmHg during the acute stage of SAH and vasospasm, confirmed by transcranial Doppler ultrasound (TCD) or neurological examination, and neck remnants, are risk factors that affect the growth. Conclusions: Short term follow-up angiography is thus important for patients with untreated unruptured cerebral aneurysms after the acute stage of SAH.

Chronic Subdural Hematomas: Pathophysiological Studies with MR Imaging and SEP

Comparative evaluations of the MR findings, clinical symptoms, and hematoma fluid contents of 19 chronic subdural hematomas(CSHs) in 16 patients were performed to clarify the etiology of the development of CSH. CSHs were classified into four groups according to the MR findings. Hematomas showed iso-or hypointense on T1-weighted(T1-W) images and proton density-Weighted(D-W) images and hypointense on T2-weighted(T2-W) images in 6 CSHs (group A). They were hyperintense on T1-W and D-W images and hypointense on T2-W images in group B (10 CSHs) and hyperintense on T1-W, D-W, and T2-W images in 2 CSHs (group C). In the remaining CSH (group D), the hematoma showed mildly hypointense on T1-W images, isointense on D-W images, and hyperintense on T2-W images (group D). The intervals between the onset of symptoms and MR examinations were less than 5 days in 5 of 6 CSHs of group A, 4–16 days in all but one CSHs of group B (the exceptional one being an incidental case), 22 and 32 days in group C, and 46 days in group D. RBC counts, Hb, and the Hct of the hematoma fluid were also the highest in group A and the lowest in group D. This finding indicates that large amount of rebleeding took place as neurological symptoms developed and that rebleeding into a hematoma cavity was also responsible for the enlargement of CSH. The central conduction times (CCTs) of somatosensory evoked potentials(SEPs) were examined, because not only the motor pathway but also the sensory pathway should be affected by the extraaxial mass. CCTs were examined in 8 of 14 CSHs with motor weakness, however no case showed an abnormality of the sensory pathway. This suggests that the motor function was more vulnerable to extraaxial compression than the sensory pathway. Further studies are indicated for the evaluation of these mechanisms.