Biomedical subjects

Y Pierre Gobin

Publications and source records attributed to Y Pierre Gobin.

25 records · Page 2Linked to original sources

PubMed2002

Late secondary ischemic injury in patients receiving intraarterial thrombolysis.

Although animal models have demonstrated that late secondary cerebral injury after arterial occlusion and subsequent recanalization may limit the benefit of reperfusion therapy, this phenomenon has not been well characterized in humans. Diffusion-perfusion magnetic resonance imaging studies were performed before treatment, early after treatment, and at day 7 in patients undergoing vessel recanalization with intraarterial thrombolytics. Among 18 patients studied, mean age was 71 (range, 27-94), and median entry National Institutes of Health Stroke Scale score was 13 (range, 6-25). Early after recanalization, partial or complete normalization of diffusion imaging abnormalities occurred in 8 of 18 (44%) patients. Among the eight patients with early diffusion imaging reversal, late secondary injury by day 7 occurred in 5 (63%), and sustained normalization of all reversed tissue occurred in 3 (38%). Pretreatment apparent diffusion coefficient values were lowest in regions experiencing no reversal (mean apparent diffusion coefficient, 608 microm(2)/sec), intermediate in regions with reversal and secondary decline (617 microm(2)/sec), and highest in regions with sustained reversal (663 microm(2)/sec). There was a trend toward less improvement in neurological deficit in patients with secondary injury versus patients with sustained reversal. In the future, late secondary tissue injury may become an important therapeutic target for postreperfusion neuroprotective therapies, with treatment efficacy monitored by serial diffusion magnetic resonance imaging.

Adult↗

PubMed2002

Management of intraprocedural arterial thrombus in cerebral aneurysm embolization with abciximab: technical case report.

OBJECTIVE AND IMPORTANCE: Thromboembolic complications after cerebral aneurysm treatment with Guglielmi detachable coils (Boston Scientific/Target, Fremont, CA) are not infrequent; in a University of California, Los Angeles institutional review of 720 treated aneurysms, thromboembolic complications occurred in 2.5% of cases. The development of intraluminal thrombus during the embolization procedure, however, may be diagnosed promptly and treated effectively with appropriate therapy. This report describes the use of intravenously administered abciximab for the treatment of intraprocedural arterial thrombus encountered during the coil embolization of a recently ruptured anterior communicating artery aneurysm. CLINICAL PRESENTATION: A 45-year-old man presented with severe headache 12 days before transfer to our institution. He had no neurological deficits at admission. Previous computed tomography of the brain demonstrated subarachnoid hemorrhage, and magnetic resonance angiography from the other institution demonstrated a 4-mm anterior communicating artery aneurysm. INTERVENTION: The patient underwent Guglielmi detachable coil embolization of the aneurysm under systemic heparinization. During the embolization, however, a thrombus developed in the proximal left A2 segment. The patient was given an intravenous infusion (20 mg) of abciximab for 10 minutes, and within 15 minutes dissolution of the thrombus was observed with no angiographic evidence of distal emboli. After reversal of general anesthesia, the patient exhibited minimal right leg weakness, which resolved within 1 hour. CONCLUSION: Abciximab may be a useful adjunct for endovascular treatment of patients with cerebral aneurysms in whom intraprocedural arterial thrombus is encountered.

Abciximab↗

PubMed2002

Magnetic resonance imaging detection of microbleeds before thrombolysis: an emerging application.

BACKGROUND: Hemorrhagic transformation (HT) is a major complication of thrombolytic treatment for acute ischemic stroke. Although a history of prior intracerebral hemorrhage diagnosed by head CT is a contraindication to thrombolysis, there are no guidelines or data regarding evidence of prior asymptomatic microbleeds visualized with T2*-weighted magnetic resonance imaging (MRI). METHODS: Pretreatment T2*-weighted MRI sequences were retrospectively analyzed in all patients receiving intra-arterial thrombolytic therapy and undergoing a pretreatment MRI at our institution. The frequency and location of prior microbleeds was determined and compared with the frequency and location of secondary HT after therapy. RESULTS: Five of 41 patients undergoing MRI before receiving intra-arterial thrombolytic therapy demonstrated evidence of prior microbleeds on the pretreatment MRI studies. Major symptomatic hemorrhage occurred in 1 of 5 patients with microbleeds compared with 4 of 36 patients without. Only 1 patient in the entire 41-patient cohort experienced any HT outside the acute ischemic field. In this patient, the symptomatic hemorrhage occurred directly at the site of a prior microbleed, contralateral to the acute ischemic event. CONCLUSIONS: Old silent microbleeds, visualized with T2*-weighted MRI sequences, may be a marker of increased risk of HT in patients receiving thrombolytic therapy for acute ischemic stroke. Pretreatment screening of thrombolytic candidates with these MRI sequences may be useful in the future to identify these patients.

Acute Disease↗

PubMed2002

Predictors of hemorrhagic transformation in patients receiving intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: Hemorrhagic transformation (HT) is a major complication of intra-arterial (IA) thrombolytic therapy. Identifying significant predictors of hemorrhage after thrombolysis would be useful in guiding patient selection for IA treatment. METHODS: Data were collected retrospectively on consecutive patients with acute focal cerebral ischemia within the anterior or posterior circulation who were treated with combined intravenous (IV)-IA or pure IA thrombolysis over an 8-year period at the UCLA Medical Center. RESULTS: Eighty-nine patients were treated. Median baseline National Institutes of Health Stroke Scale (NIHSS) score was 16, and mean age was 69 years. Twenty-six patients received IA tissue plasminogen activator (tPA) only, 22 received IV-IA tPA, and 41 received IA urokinase only. Asymptomatic HT occurred in 29 patients (33%), minor symptomatic HT (1- to 3-point worsening in NIHSS score) occurred in 10 patients (11%), and major symptomatic HT (> or = 4-point worsening in NIHSS score) occurred in 6 patients (7%). The rate of any HT was similar in patients treated with pure IA thrombolysis (39%) versus combined IV-IA thrombolysis (41%). In pure IA cases, the rate of any HT was 50% with tPA versus 32% with urokinase (P=0.2). Eighty-six percent of the patients with HT versus 39% of the patients without HT were dead or disabled (modified Rankin score >2) at day 7 (P<0.0001). On multivariate analysis, independent predictors of any HT were higher NIHSS score, longer time to recanalization, lower platelet count, and higher glucose level. A model using these variables correctly predicted HT with positive predictive value 70% and overall accuracy 78%. CONCLUSIONS: In this large series of IA thrombolysis, rates of HT were similar to those demonstrated in prior series and clinical trials. Higher NIHSS score, longer time to recanalization, lower platelet count, and higher glucose level were independent predictors of any HT.

Academic Medical Centers↗

PubMed2002

Adult pial arteriovenous fistula and superior sagittal sinus stenosis: angiographic evidence for high-flow venopathy at an atypical location. Case report.

The authors present the case of a 69-year-old man who suffered from bilateral cortical venous hypertension due to a brain pial arteriovenous malformation (AVM) with a high-flow fistula. The AVM became complicated by the development of a high-grade stenosis of the posterior superior sagittal sinus (SSS). A comparison of cerebral angiograms obtained at different times revealed that the severe SSS stenosis had developed within a 5-year period and was located distal to the nidus of the left parietal AVM nidus, away from the entrance of the dominant superior superficial cortical draining vein into the SSS. The high-flow fistula was occluded with detachable coils and the AVM nidus was further embolized with acrylic. The SSS stenosis was mechanically dilated by means of balloon angioplasty and stent placement. This case provides angiographic evidence to support the hypothesis that a pial arteriovenous fistula in an adult can cause high-flow occlusive venopathy in a major sinus within a relatively short time and that this acquired high-flow occlusive venopathy can develop at an atypical location distant from the nidus of the AVM.

Aged↗

PubMed2002

Three-dimensional helical computerized tomography angiography in the diagnosis, characterization, and management of middle cerebral artery aneurysms: comparison with conventional angiography and intraoperative findings.

OBJECT: Middle cerebral artery (MCA) aneurysms can be difficult to detect and characterize. The authors describe the utility and impact of helical computerized tomography (CT) angiography for the evaluation of aneurysms in this location, and compare this modality with digital subtraction (DS) angiography and intraoperative findings. METHODS: Two hundred fifty-one patients with suspected cerebral aneurysms underwent CT angiography. Two-dimensional multiplanar reformatted images and three-dimensional CT angiograms were examined by two independent readers in a blinded fashion. Results were compared with findings on DS angiograms to determine the relative efficacy of these modalities in the detection and characterization of aneurysms. Questionnaires completed by neurosurgeons and endovascular therapists were used to determine the impact of CT angiograms on aneurysm management. Twenty-eight patients harboring 31 MCA aneurysms and 26 patients without aneurysms were identified using CT angiography. The sensitivity of CT angiography and DS angiography for MCA aneurysms was 97%; both techniques showed 100% specificity. In 76% of evaluations, the CT angiography studies provided information not available on DS angiography examinations. For the characterization of aneurysms, CT angiography was rated superior (72%) or equal (20%) to DS angiography in 92% of cases evaluated (p < 0.001). Computerized tomography angiography was evaluated as the only study needed for patient triage in 82% of cases (p < 0.001), and as the only study needed for treatment planning in 89% of surgically treated (p < 0.001) and in 63% of endovascularly treated cases (p < 0.001). The information acquired on CT angiograms changed the initial treatment plan in 24 (67%) of these 36 complex lesions (p < 0.01). The aneurysm appearance intraoperatively was identical or nearly identical to that seen on CT angiograms in 17 (89%) of 19 of the surgically treated cases. CONCLUSIONS: Computerized tomography angiography has unique advantages over DS angiography and is a viable alternative to the latter modality in the diagnosis, triage, and treatment planning in patients with MCA aneurysms.

Adult↗

PubMedDate not supplied

Endovascular management of dolichoectasia of the posterior cerebral artery report.

Congenital or nonatherosclerotic dolichoectasia is a rare condition; its etiology, natural history, and indications and technique of treatment are not yet clarified. During a workup for recent headaches and left-sided paresthesia in a 48 year-old female patient, brain MR imaging and cerebral angiography showed a large dolichoectasia of the P2 segment of the right posterior cerebral artery (PCA). The patient passed endovascular testing for occlusion of P2 with both balloon test occlusion and selective amytal testing. Endovascular coil occlusion of the right PCA dolichoectasia was successfully performed with hydrogel coils.

Amobarbital↗