Search PubMed⌕ Search

Biomedical subjects

P Bergeron

Publications and source records attributed to P Bergeron.

At least 19 recordsLinked to original sources
PubMed2001

Current status of carotid bifurcation angioplasty and stenting based on a consensus of opinion leaders.

OBJECTIVE: Carotid bifurcation angioplasty and stenting (CBAS) has generated controversy and widely divergent opinions about its current therapeutic role. To resolve differences and establish a unified view of CBAS' present role, a consensus conference of 17 experts, world opinion leaders from five countries, was held on November 21, 1999. METHODS: These 17 participants had previously answered 18 key questions on current CBAS issues. At the conference these 18 questions and participants' answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus, (prevailing opinion), or divided opinion (disagreement). RESULTS: Conference discussion added two modified questions, placing a total of 20 key questions before the participants, representing four specialties (interventional radiology, seven; vascular surgery, six; interventional cardiology, three; neurosurgery, one). It is interesting that consensus was reached on the answers to 11 (55%) of 20 of the questions, and near consensus was reached on answers to 6 (30%) of 20 of the questions. Only with the answers to three (15%) of the questions was there persisting controversy. Moreover, both these differences and areas of agreement crossed specialty lines. Consensus Conclusions: CBAS should not currently undergo widespread practice, which should await results of randomized trials. CBAS is currently appropriate treatment for patients at high risk in experienced centers. CBAS is not generally appropriate for patients at low risk. Neurorescue skills should be available if CBAS is performed. When cerebral protection devices are available, they should be used for CBAS. Adequate stents and technology for performing CBAS currently exist. There were divergent opinions regarding the proportions of patients presently acceptable for CBAS treatment (<5% to 100%, mean 44%) and best treated by CBAS (<3% to 100%, mean 34%). These and other consensus conclusions will help physicians in all specialties deal with CBAS in a rational way rather than by being guided by unsubstantiated claims.

Angioplasty↗
PubMed2000

Global experience in cervical carotid artery stent placement.

The purpose of this article is to review and update the current status of carotid artery stent placement in the world. Surveys to major interventional centers in Europe, North and South America, and Asia were initially completed in June 1997. Subsequent information from these 24 centers in addition to 12 new centers has been obtained to update the information. The survey asked the various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 5,210 procedures involving 4,757 patients. There was a technical success of 98.4% with 5,129 carotid arteries treated. Complications that occurred during the carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 134 transient ischemic attacks (TIAs) for a rate of 2.82%. Based on the total patient population, there were 129 minor strokes with a rate of occurrence of 2.72%. The total number of major strokes was 71 for a rate of 1.49%. There were 41 deaths within a 30-day postprocedure period resulting in a mortality rate of 0.86%. The combined minor and major strokes and procedure-related death rate was 5.07%. Restenosis rates of carotid stenting have been 1.99% and 3.46% at 6 and 12 months, respectively. The rate of neurologic events after stent placement has been 1.42% at 6-12-month follow-up. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative for vascular surgery, especially for patients that are high risk for standard carotid endarterectomy. The periprocedure risks for major and minor strokes and death are generally acceptable at this early stage of development and have not changed significantly since the first survey results. Cathet. Cardiovasc. Intervent. 50:160-167, 2000.

Carotid Stenosis↗
PubMed2000

Combined minimaly invasive surgery for coronary bypass and abdominal aortic occlusion.

Association of extracorporal assisted coronary bypass with peripheral vascular surgery is already commonplace in the therapeutic arsenal. This case report presents a combined cardiac and vascular surgery in a high risk patient, with unstable angina following myocardial infarction and critical ischemia of a single lower limb. Synchronous minimally invasive direct coronary bypass graft and extra-anatomic aorto-profundal bypass in one single sitting were performed. The procedure was successful at 6 months follow up. We believe that this type of synchronous procedure, minimising surgical aggression, could be effective in selected high risk patients.

Aged↗
PubMed2000

First-generation aortic endografts: analysis of explanted Stentor devices from the EUROSTAR Registry.

PURPOSE: To examine the structure and healing characteristics of chronically implanted Stentor endografts that were explanted due to migration, endoleak, thrombosis, or aneurysm expansion. METHODS: The devices were harvested following reoperation (n = 5) or autopsy (n = 1) with implantation times ranging from 13 to 53 months. Structural modifications to the metal components were examined using radiography, endoscopy, and magnetic resonance imaging (MRI). Specimens taken from components of the modular stent-grafts were examined histologically and with scanning electron microscopy (SEM) to assess healing behavior. Physical and chemical stability of the nitinol wires and woven polyester graft material was evaluated using SEM and electron spectroscopy for chemical analysis. RESULTS: Although the endografts were retrieved for a variety of reasons, they exhibited similar healing and structural modifications. The woven polyester sleeve showed evidence of yarn shifting and distortion, yarn damage, and filament breakage leading to the formation of openings in the fabric. The luminal surface endografts showed incomplete healing characterized by a poorly organized, nonadherent thrombotic matrix of variable thickness. Radiographic and endoscopic observations indicated that structural failure of the grafts, particularly in the main aortic component, was related to severe compaction and dislocation of the metallic frame due to suture breaks. Corrosion marks were observed on some nitinol wires in all devices. Chemical analysis and ion bombardment of the nitinol wires revealed that the surface concentrations of titanium and nickel were not homogenous. The first layer was composed of carbon or organic elements, followed by a stratum of highly oxidized titanium with a low nickel concentration; the titanium-nickel alloy lay beneath these layers. CONCLUSIONS: Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.

Aged↗
PubMed1999

Percutaneous stenting of the internal carotid artery: the European CAST I Study. Carotid Artery Stent Trial.

PURPOSE: To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons. METHODS: Symptomatic or asymptomatic patients > or = 65 years of age with internal carotid artery (ICA) stenoses > or = 70% and < or = 2-cm long were eligible for enrollment. The procedures were performed in an operating room with the choice of anesthesia and the percutaneous access site at the discretion of the surgeon. Only Palmaz stents were used. RESULTS: From January 1, 1996 to December 31, 1997, 99 patients (74 men, mean age 70 years, range 51 to 94) were enrolled in the study. More than half (57 of 99 patients) were asymptomatic. The direct cervical approach was used predominantly (97%). Three (3%) cases were converted to surgery for inability to access the artery or deploy the stent (technical success 97%). No perioperative death or myocardial infarction was reported. Six (6%) procedural complications included 1 reversible arterial spasm, 2 dissections, 1 cervical hematoma, and 2 residual stenoses. One neurological event reversed within 7 days (1% minor stroke rate) and 4 (4%) transient ischemic attacks resolved within 24 hours. One (1%) asymptomatic early occlusion occurred 2 days postoperatively. No neurological event was observed in the 1- to 24-month follow-up (mean 13 months). Two (2%) patients died of nonprocedurally related causes. No stent compression was seen, but 1 asymptomatic occlusion and 3 asymptomatic, non-flow-limiting restenoses (2 < 40%, 1 at 60%) were found within 1 year (3% restenosis rate on an intention-to-treat basis). Patency was 98% at 1 year. CONCLUSIONS: The results of this trial support the contention that carotid stenting of short ICA lesions can be performed with a low neurological complication rate.

Aged↗
PubMed1998

Current global status of carotid artery stent placement.

Our purpose was to review the current status of carotid artery stent placement throughout the world. Surveys were sent to major interventional centers in Europe, North and South America, and Asia. Information from peer-reviewed journals was also included and supplemented the survey. The survey asked various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. Of the centers which were sent surveys, 24 responded. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 2,048 cases, with a technical success of 98.6%. Complications that occurred during carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 63 minor strokes, with a rate of occurrence of 3.08%. The total number of major strokes was 27, for a rate of 1.32%. There were 28 deaths within a 30-day postprocedure period, resulting in a mortality rate of 1.37%. Restenosis rates of carotid stenting have been 4.80% at 6 mo. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative to vascular surgery, especially for patients that are at high risk for standard carotid endarterectomy. The periprocedural risks for major and minor strokes and death are generally acceptable at this early stage of development.

Angioplasty, Balloon↗
PubMed1998

Hemodynamics of endovascular prostheses.

A surgical study (Bergeron et al., 1991, International Angiology 10(3), 182-186) picked out that re-endothelialization of implanted expandable stents, frequently used to reduce the recurrent stenosis rate after balloon angioplasty, was correct and more rapid in femoro-popliteal arteries (quasi-straight vessels) than in iliac arteries (bifurcated vessels). Since it is now well known that local hemodynamics are considered to be an important atherogenic factor, we decided to compare and optimize the shape of the existing equipment, in order to further give some informations to surgeons about the optimal stenting at the site of bifurcation. Therefore, we studied in vitro (1) the influence of the protruding part of a stent on the flow patterns in the branches of an aorto-iliac bifurcation model, and (2) the possibility of reducing or preventing this impact. Qualitative information was obtained from visualizations in the horizontal median plane of the bifurcation model, while Doppler ultrasonic velocimetry provided quantitative data, at different points of the cardiac cycle. Results showed that a standard stent implanted in a daughter branch of the bifurcation may have a considerable influence on flow behaviour when it is sticking out of the daughter branch. A new design of stent, with a bevelled shape, showed a significant reduction of flow disturbance.

Aorta↗
PubMed1997

Inhibition of cell growth by overexpression of the ZPK gene.

ZPK is a recently described serine/threonine protein kinase that is thought to be involved in the regulation of cell proliferation and differentiation. To directly determine whether ZPK exhibits any effect on cell growth, NIH 3T3 fibroblasts were transfected with an expression vector harboring the murine ZPK cDNA. Stable expression of this construct led to a dramatic reduction in the proliferative capacity of these cells as measured by a colony formation assay in monolayer culture. By contrast, overexpression of a ZPK cDNA with a mutation in the ATP-binding domain did not affect clonal expansion of the transfected cells. These findings suggest that the ZPK gene may act as a negative regulator of cell growth and that this function may be mediated in part by the intrinsic kinase activity of the ZPK protein.

3T3 Cells↗
PubMed1997

Women physicians in Quebec.

This article presents the results of a qualitative study on women physicians in Quebec which aimed to go beyond a mere statistical description of the tendencies observed in their practices. It proposes an interpretation of their discourses on their practice and its context bringing to light the interdependence of individual strategies and structural constraints. We met 30 women physicians and eight men physicians asking them to talk freely about their personal and professional experience. The data reveal how the individual characteristics and interests of women physicians prevail in their decisions at key moments in their lives which have repercussions on the shaping of their practice. These moments include admission into the faculty of medicine, training, professional orientation and the choice of a specialized field, organization of professional practice and personal life. The medical practice of women is constructed through these choices and the gender variable plays a more or less significant role at each stage of this construction. Their distinctive choices reflect how gender relations are reproduced in the private sphere and the interactions between their private and professional lives. According to our participants, a difference lies in the place occupied by their profession in women and men physicians' lives. The private life of women physicians appears to be closely linked to their decisions regarding the organization of their professional life and as a result to the health services they provide, suggesting they have their own way of "being a physician". The individual nature of the strategies they adopt can have, at a collective level, consequences on the planning and the distribution of medical resources in the publicly managed health care system in Quebec while raising the global issue of gendered division of labor.

Adaptation, Psychological↗
PubMed1997

Evaluation of endovascular abdominal aortic aneurysm repair: anatomical classification, procedural success, clinical assessment, and data collection.

PURPOSE: To detail a methodology for evaluation of endovascular abdominal aortic aneurysm (AAA) repair that has been achieved through consensus of an international multidisciplinary team of investigators. METHODS: This schema features an anatomical classification for AAAs, a definition of procedural success, and a procedure for clinical assessment, as well as the necessary data collection forms. Patient data include demographics, procedural and clinical success, complications, and follow-up. Procedural details can be related to anatomic situations, comorbid processes, devices, and effective aneurysmal exclusion. RESULTS: These data would allow assessment of the procedures, physician learning curves, procedural indications, techniques, methodologies, the relationship of indications to success and complications, devices and subsequent graft patency, and aneurysmal exclusion. CONCLUSIONS: The use of this standardized data collection system could enable physicians and industry to better understand endovascular AAA repair and ultimately improve patient care.

Aortic Aneurysm, Abdominal↗
PubMed1997

Endoluminal repair of large abdominal aortic aneurysms using PTFE: a feasibility study.

PURPOSE: To investigate the feasibility of using predilated thin-wall polytetrafluoroethylene (PTFE) secured by extra-large Palmaz stents for endoluminal repair of abdominal aortic aneurysms (AAA). METHODS: Thirty-two patients (26 males; aged 69 to 83 years) from three centers (two in Europe, one in Australia) were selected for endoluminal stent-grafting using predilated B-mm PTFE graft material fitted with extra-large Palmaz stents at the terminal ends. Aortoaortic tube grafts were implanted in 12 patients, while the remainder received aortomonoiliac endografts and femorofemoral bypass. Follow-up at 5 days and then biannually was by contrast-enhanced computed tomography (CT) or duplex scanning. RESULTS: There were 13 conversions to open surgery; these patients died within 30 days. Nineteen patients were discharged with functioning endografts within 5 days of treatment. Of these, two have had their grafts removed owing to infection in one and distal stent migration in the other. Two endoleaks have been detected in follow-up; one has been sealed by covered stenting. One twisted graft was repaired by Wallstent implantation. Seventeen patients remain well, one with persistent distal endoleak, but none shows an increase in AAA diameter on imaging over the 6- to 26-month (median 13) follow-up. CONCLUSIONS: These results represent the learning curves of three separate centers. Technical failure and complications were more common early in the study. Advantages of the technique include relative low cost and the ability to tailor the stent-graft to the individual aneurysm.

Aged↗
PubMed1996

Cell-specific expression of the ZPK gene in adult mouse tissues.

ZPK is a recently identified human putative protein kinase gene that encodes an unusual serine/threonine kinase containing two potential leucine zipper motifs similar to those found in transcription factors as well as in members of the newly discovered mixed-lineage family of protein kinases. To study the normal biological function of ZPK, we have isolated a mouse ZPK cDNA and examined the pattern of ZPK mRNA expression in adult mouse tissues by Northern blot and in situ hybridization analyses. The predicted open reading frame of this cDNA encodes an 888-amino-acid protein that shares 95% overall identity with its human counterpart. By Northern blot analysis, we detected expression of ZPK mRNA in the brain of adult mice, but not in any other tissue tested. In situ hybridization analysis of mouse brain sections revealed specific association of ZPK mRNA with neuronal cell populations, primarily in the hippocampus, the cerebral cortex, and the Purkinje cell layer of the cerebellum. Interestingly, a remarkable pattern of cell-type-specific expression was also found in the epithelial compartment of various organ systems, including stomach, small intestine, liver, and pancreas, as well as in the seminiferous tubules of mature testes. Taken together, these observations suggest that ZPK could play a role in development, function, and maintenance of a variety of specialized cells.

Amino Acid Sequence↗
PubMed1996

Local anesthesia in carotid angioplasty.

PURPOSE: To determine the safety and efficacy of local anesthesia for percutaneous carotid angioplasty and stenting performed via a direct common carotid access. METHODS: Deep cervical plexus blockade was used for anesthesia in 22 of 32 patients (26 males; mean age 66 years) undergoing percutaneous carotid balloon angioplasty and/or stenting via direct carotid puncture. Local anesthesia was selected according to patient preference (n = 9); advanced age (n = 4); ischemic heart disease (n = 4); intended extracorporeal circulation for unstable angina (n = 3); and an incompetent circle of Willis (n = 2). The technique involved injection of bupivacaine hydrochloride along the C2, C3, and C4 transverse processes. No superficial cervical plexus blockade was used. RESULTS: No complications of anesthesia were observed, though there were cases in which surgery became necessary under local anesthesia for angioplasty-related complications. These conversions were accomplished without difficulty. CONCLUSIONS: Cervical nerve blockade appears to be a safe and effective anesthetic method for endovascular carotid interventions performed percutaneously through direct carotid puncture.

Age Factors↗
PubMed1996

Recurrent carotid disease: will stents be an alternative to surgery?

PURPOSE: To report the results of balloon angioplasty in recurrent carotid occlusive disease and evaluate the potential for stent implantation. METHODS AND RESULTS: Between April 1991 and September 1995, 15 patients with carotid restenosis underwent 17 endoluminal procedures in 3 common carotid and 14 internal carotid arteries. Two postdilation complications (dissection and acute occlusion) required prompt stenting; one common carotid artery was stented for postdilation residual stenosis. One recurrent lesion was also stented 6 months after initial angioplasty. One stroke, 1 silent cerebral infarction, and 3 transient ischemic attacks occurred in the balloon angioplasty patients (33% neurological complication rate). The common carotid stent patient died 3 days postoperatively due to hyperperfusion syndrome. Long-term follow-up in two stent patients showed no restenosis at 18 and 48 months, respectively. The 11 balloon angioplasty patients likewise have not demonstrated restenosis. CONCLUSIONS: Balloon angioplasty alone appears too risky for treating recurrent carotid disease. Stents may offer a safer alternative, particularly when implanted primarily.

Aortic Dissection↗
PubMed1996

Carotid angioplasty and stenting: will periprocedural transcranial Doppler monitoring be important?

PURPOSE: To explore the value of transcranial Doppler (TCD) ultrasonography in the periprocedural monitoring of patients undergoing angioplasty procedures for stenosis of the internal carotid artery. METHODS: Thirty-two patients were included in the study between April 1991 and September 1995 (6 females, 26 males; average age 66 years). All patients were interrogated before and after angioplasty by a standard TCD examination protocol. Intraprocedurally, TCD was used continuously to monitor cerebral blood flow and supply evidence of embolic particulates. Nineteen patients were treated by percutaneous transluminal angioplasty (PTA) alone; the other 13 underwent primary stent (PS) implantation. RESULTS: High-intensity transient signals indicative of emboli appeared to be more frequent in the PTA group than in the PS cohort. Preoperative TCD identified 3 (9%) high-risk patients with incompetent collateral pathways through the circle of Willis. Intraoperatively, TCD detected two postdilation carotid occlusions, a sylvian embolism, and one case of arterial spasm. The preprocedural TCD in a patient with contralateral carotid occlusion showed good collateral circulation, providing reassurance during conversion to endarterectomy when an undeployed stent obstructed blood flow. Postoperatively, TCD confirmed restored intracerebral circulation and identified one hyperperfusion syndrome. CONCLUSIONS: TCD is a simple, relatively inexpensive examination that can preprocedurally identify carotid stenosis patients at high risk for intraoperative cerebral ischemia in whom PTA might be preferable to surgery. During the procedure, TCD can document the benefits of endovascular treatment and offer early detection of ischemic complications.

Aged↗
PubMed1996

Cervical carotid artery stenosis: which technique, balloon angioplasty or surgery?

METHODS: Between April 1991 and November 1995, 38 patients mean age 65 (6 females, 32 males) were treated by cervical puncture for isolated cervical carotid stenosis (33 internal, 1 external, and 6 common carotid). All patients but 5 were symtomatic (19 TIA, 7 amarosis, 2 strokes and 4 VB symptoms). Complex lesions involving the carotid bifurcation and heavy calcifications were treated by conventional surgery. Two different groups of patients were considered. A first group of 19 patients (17 restenosis, 1 primary, 1 FM dysplasia) was treated by simple balloon angioplasty (BA). A second group of 19 patients was treated by primary stenting (16 DF NOVO, 2 radio-induced, and 2 recurrent stenosis). RESULTS: No hematoma required surgery. In the first group one patient died from an intracerebral hemorrhage, one presented a reversible stroke and 3 others a TIA. In the second group there was no complication or silent infarction on the CT SCAN: CONCLUSIONS: Balloon angioplasty appears to be associated with a high neurologic risk. While primary stenting seems much more reliable. A longer follow-up to deal with restenosis. Conventional surgery remains the gold standard.

Aged↗