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Biomedical subjects

F Koskas

Publications and source records attributed to F Koskas.

At least 19 recordsLinked to original sources
PubMed1999

Endovascular treatment of aortoiliac aneurysms: made-to-measure stent-grafts increase feasibility.

We describe here our preliminary experience with use of a range of made-to-measure stent-grafts made from commercially available components. From January 1996 to June 1998, 94 aortoiliac aneurysms (AIA) were treated with stent-grafts that were made to measure using Z autoexpandable stainless steel stents connected with polyester sutures and covered with commercially available polyester vascular prostheses. These stent-grafts were implanted through 18 to 24 (typically 20) Fr commercially available introducers via a surgical remote access. Made-to-measure tubular, bifurcated, tapered, and/or blind stents combined with extraanatomic bypass designs increased the rate of endovascular treatment (ET) of AIA in this series. This rate was further increased through the use of uncovered proximal or distal stents when dealing with short or tortuous necks near major collaterals and through use of hybrid, partly surgical designs, one with stented and the other with stentless ends, the latter allowing for a surgically made anastomosis. The results of our experience with these techniques show that use of made to-measure stent-grafts greatly increases the feasibility of the ET of AIA among unselected patients while offering enough efficiency and safety to deserve further investigation.

Aortic Aneurysm, Abdominal↗
PubMed1998

Computerized tomographic angiography scan following carotid endarterectomy.

The purpose of this study was to evaluate the role of computed tomographic angiography (CTA) for postoperative assessment of carotid endarterectomy (CE). Twenty carotid endarterectomies were performed and controlled by using (1) intraoperative angiography, (2) postoperative duplex scanning and CTA with multiprojection volume reconstruction (MPVR). Intraoperative angiographic controls were deemed satisfactory for all patients. In 12 patients, the postoperative morphological aspect was satisfactory with CTA and duplex scanning. In the eight remaining patients, CTA and/or duplex scanning revealed 12 abnormalities: 3 were equally visualized on CTA and duplex scanning, 6 only on CTA and 3 only on duplex scanning. CTA is a rapid and noninvasive technique allowing the surgeon to get informative and comparative data. It might be an interesting alternative to postoperative angiography.

Aged↗
PubMed1998

Treatment of vascular graft infection by in situ replacement with cryopreserved aortic allografts: an experimental study.

PURPOSE: The purposes of this study were to prove the efficacy of cryopreserved aortic allografts to treat an established vascular graft infection by in situ replacement in an animal model and to evaluate the role of the antibiotics normally used to decontaminate the allografts. METHODS: Twenty-three dogs underwent infrarenal aortic replacement with a gelatin-sealed knitted polyester graft contaminated in vitro by Staphylococcus epidermidis RP-62. One week later, the 18 surviving animals underwent reoperation for graft removal and were randomized into three groups for in situ replacement: group I (control, n = 6) received a new gelatin-sealed graft; group II (n = 6) received a non-antibiotic-treated cryopreserved allograft; and group III (n = 6) received an antibiotic-treated cryopreserved allograft. Control grafts and allografts were removed 4 weeks after the initial intervention for quantitative bacteriologic analysis and histologic analysis. Bacteriologic results were expressed as colony-forming units per square centimeter of graft material. Qualitative bacteriologic analysis was also obtained from perigraft fluid and tissue. RESULTS: All of the initially implanted grafts and all of the control grafts (group I) were infected at the time of removal. In group II, three out of six allografts were not totally incorporated, whereas in group III incorporation was always complete, with a significantly decreased inflammatory reaction. All of the antibiotic-treated allografts were sterile, whereas three untreated allografts grew bacteria. CONCLUSIONS: In this model, cryopreserved aortic allografts were more resistant to reinfection than synthetic grafts after in situ replacement of an infected prosthetic graft. However, the antibiotic loading of the cryopreserved aortic allograft appears to be essential to obtain optimal therapeutic effects.

Animals↗
PubMed1997

Surgery for ruptured abdominal aortic aneurysm: early and late results of a prospective study by the AURC in 1989.

This study determines the early and late survival rates, the causes of death, and prognostic variables that are associated with early and late survival after for ruptured abdominal aortic aneurysm (AAA). These are based on the prospective analysis of 628 variables of data on 158 consecutive patients in 24 centers of our association in 1989. Patients were followed up for a mean of 42.1 +/- 21.0 months. Six patients were lost to follow-up. To identify the variables that were associated with early and late survival, statistical methods included logistic regression analysis, Kaplan-Meier analysis, and Cox regression analysis. The survival rate was 52.9% +/- 14.4% at 1 month, 48.8% +/- 15.8% at 1 year, 48.1% +/- 16.0 at 2 years, 40.3 +/- 19.2% at 3 years, and 35.0 +/- 21.8 at 4 years. The cause of the 73 (46.2%) early deaths were cardiac (33), hemorrhage (29), colonic necrosis (5), stroke (2), graft infection (2), pneumonia (1), and kidney failure (1). Significant predictors of early death were the presence of a common iliac aneurysm (p < 0.02), the age of the patient (p < 0.02), a previous history of stroke or transient ischemic attack (TIA) (p < 0.04), a bifurcated graft (p < 0.04), a saccular aneurysm (p < 0.06), the blood creatinine level (p < 0.06), and hypotension on admission (p < 0.06). The causes of the 28 (17.7%) late deaths were heart disease (11), cancer (8), stroke (3), another operation (3), graft infection (1), pneumonia (1), and Alzheimer disease (1). Significant predictors of late death were heavy smoking (p < 0.03) and chronic obstructive pulmonary disease (p < 0.07). Rupture of an abdominal aortic aneurysm remains a catastrophic event. Even after a successful cure of a ruptured AAA, cardiovascular causes of death are responsible for survival rates that are significantly lower than that in a matched nonaneurysmal population.

Aged↗
PubMed1997

Long-term survival after elective repair of infrarenal abdominal aortic aneurysm: results of a prospective multicentric study. Association for Academic Research in Vascular Surgery (AURC).

During 1989, 28 centers of the Association for Academic Research in Vascular Surgery (AURC) reported all cases involving patients with infrarenal abdominal aortic aneurysm (AAA) who reached the operating room alive. In a total series of 1107 procedures, 834 were performed electively. During 1993 and 1994, an effort was made to contact and, if possible re-examine the 794 (95.2%) patients who survived these elective procedures in order to establish survival curves, determine the causes of late death, and ascertain the predictive value for long-term survival of 628 perioperative variables recorded in 1989. Survival curves were calculated using the actuarial and Kaplan-Meier methods and compared with those obtained from national statistical records in a control population matched for age and sex. Variables with potential predictive value for late death were selected by univariate statistical analysis using either the chi2 or student t-test. In the group of 794 (92.5%) patients who survived elective AAA repair in 1989, survival rates were 93.9 +/- 1.8% at 1 year, 89.5 +/- 3.2% at 2 years, 83.5 +/- 3.2% at 3 years, 77.6 +/- 3.9% at 4 years, and 66.9 +/- 10.6% at 5 years. These rates were significantly lower than those observed in the control population. The mean annual death rate from cardiovascular disease was 1.8%, which was higher than in the control population matched for age and sex. Analysis using the Cox proportional risk model showed that the following variables were significant, independent predictors of late death: diameter of aneurysm (p < 0.02), choice of surgical approach in function of general status (p < 0.02), left ventricular insufficiency (p < 0.02), age (p < 0.02), carotid artery occlusion (p < 0.03), use of a surgical approach other than lobotomy (p < 0.04), cardiac arrhythmia (p < 0.04), duration of aortic clamping (p < 0.05), ECG evidence of myocardial ischemia (p < 0.05), abnormality at the upper limit of the aneurysm (p < 0.05), and advanced renal insufficiency (p < 0.05). Life expectancy in patients that undergo successful AAA repair is lower than in the general population. Although death is often unrelated to AAA or the repair procedure, the incidence of morbidity due to cardiovascular disease is higher than in a control population matched for age and sex. These findings suggest that better management of concurrent cardiovascular disease during the perioperative period and long-term follow-up holds the key to improving life expectancy in patients undergoing AAA repair.

Adult↗
PubMed1997

Occlusive fibromuscular disease of arteries supplying the brain: results of surgical treatment.

Occlusive fibromuscular disease (FMD) of arteries supplying the brain is a documented cause of neurologic complications. From September 1976 to December 1994, 70 patients underwent surgery for occlusive FMD involving arteries supplying the brain. Isolated dysplastic aneurysms and coilings or kinkings were not included in this series. Twenty-two patients had experienced previous nonlethal ischemic stroke, 25 patients had experienced transient ischemic attacks, and 32 patients had vertebrobasilar insufficiency with or without associated carotid symptoms. Lesions involved one (n = 36) or two (n = 29) internal carotid arteries, and one (n = 18) or two (n = 14) vertebral arteries. Twenty-seven patients had simultaneous involvement of both carotid and vertebral arteries. Ten patients had FMD at another site, four had intracranial aneurysm, and four had an aberrant right subclavian artery. Seventy-seven carotid procedures including 67 graduated intraluminal dilatations were performed and 18 vertebral arteries were revascularized. One patient (1.4%) died postoperatively from hemorrhagic stroke and two patients (2.8%) presented nonlethal stroke. Sixty-two patients were followed postoperatively from 2 to 184 months (mean 86.2 +/- 54.4). Actuarial survival rates at 5 and 10 years were 96.4 +/- 5.0% and 82.1 +/- 14.9%, respectively. Actuarial primary patency rate at 5 and 10 years was 94.3 +/- 5.5%. Actuarial probability of stroke-free survival rates at 5 and 10 years were 94.2 +/- 5.6% and 88.6% +/- 10.3%, respectively. We conclude that improvement of symptoms, prevention of stroke, and stable long-term results justify surgical treatment in symptomatic patients with FMD of arteries supplying the brain.

Adolescent↗
PubMed1997

[Aneurysm of the thoracic aorta and spondylodiscitis disclosing brucellosis].

Brucellosis, which decreased during the eighties in France, remains a public health problem in many Mediterranean countries. We report the case of a 65-year old patient native of Morocco, of thoracic aorta aneurysm and lumbar spondylodiscitis due to Brucella melitensis, revealed by haemoptysis and lumbar pains, with a favourable outcome after aortic graft resection, spinal plaster immobilization and specific lengthy antibiotic treatment. This case report is characterized by the absence of endocarditis or infectious focus near the aneurysm. Diagnosis of aneurysm and spondilitis due to Brucella melitensis is based on imaging and bacteriological and serological examination. Because of a clinical and biological intolerance for rifampicin and cotrimoxazole, this patient received ofloxacin-doxycyclin-streptomycin. We discuss antibiotic recommendations and stress the interest of the early diagnosis of complicated forms of brucellosis for a better prognosis.

Aged↗
PubMed1997

[Abdominal aortic aneurysms: contribution of genetics. From atheromatous theory to parietal theory].

Abdominal aortic aneurysms have usually been characterized as atheroslcerotic, but this view of their pathogenesis is a restricted one. As yet, no unified concept of pathogenesis has emerged, bat several factors appear to have an important role, including familial clustering, genetically determined and acquired biochemical alterations in the structural matrix of the aortic wall and bemodynamic mechanical factors. We review literature data concerning new pathogenic concepts of abdominal aortic aneurysms and particularly familial predisposition. Ultrasonographic screening is recommended in brothers (50 years) of patients with aneurysms of the abdominal aorta.

Aortic Aneurysm, Abdominal↗
PubMed1997

[Inflammatory aneurysms of the thoracic aorta. Surgical aspects].

In the Western world, inflammatory aneurysms account for only 1 to 5%, of all operated thoracic aorta aneurysms. Takayasu's disease is by far the commonest cause although all forms of aortitis may result in aneurysm formation. Usually observed in young patients, these aneurysms are suitable for often major surgery with results that are globally better than in degenerative or dissecting aneurysms. However, they pose, two specific problems: the progression of the inflammatory disease which may require pre- and/or post-operative steroid therapy and that of the risk, at least in theory, of a late pseudo-aneurysm, which justifies regular long-term follow-up after surgery.

Aneurysm, False↗
PubMed1996

[Medical treatment of aortic abdominal aneurysms. Outstanding questions].

The low mortality of programmed surgical treatment of aortic abdominal aneurysms (2-4%) contrasts with a high mortality of surgical treatment in case of rupture (70-90%). These data underline the benefit of a "prophylactic" surgical treatment of aortic abdominal aneurysms, even those of small size or in older patients. Recently, experimental models and results of a few clinical studies suggest that medical treatment with beta-adrenergic blocking agents may reduce the expansion rate of aortic abdominal aneurysms and thus lower the risk of rupture. Several questions remains open. Should beta-blocking agents be reserved for aneurysms more than 5 cm in diameter in patients with a contraindication for surgery, or on the contrary proposed for aneurysms less than 4 cm in diameter in patients still free of contraindications? What is the mode and delay of action for beta-blockers, their effect on modulating blood pressure and their contribution to the use of endoluminal prostheses? Controlled prospective trials enrolling a large number of patients are required to answer these questions.

Adrenergic beta-Antagonists↗
PubMed1996

[Value of an extensive biological study in venous or arterial thromboses].

OBJECTIVES: The aim of this work is to study the signification of an extensive biological evaluation in patients with "unexplained" thrombosis. We studied 78 patients with more than one arterial and/or venous thromboembolic event. METHODS: Fifty-four patients were admitted for unexplained deep venous thrombosis (group I, n = 19, 9 men and 10 women) and/or arterial thrombosis (group II, n = 35, 21 men and 14 women). A third group (group III) included 24 patients (13 men, 11 women) known to have a pathologic state which can lead to a thrombotic event. RESULTS: The patients in both groups I and II had, more often than normal subjects, a high level of homocysteinemia (26% vs 3%, p < 0.001), anti-beta 2 glycoprotein 1 (18.5% vs 3%, p < 0.001) and antiphospholipid antibodies (13% vs 3%, p < 0.02). We also found a significant association between an increase of erythrocytic aggregation and arterial thrombosis (group II). In the third group, for both arterial (n = 14) and venous (n = 10) thrombosis, we found a high level of anticardiolipin antibodies (25% vs 3%, p < 0.001), anti-beta 2 glycoprotein 1 antibodies (12.5% vs 3%, p < 0.05) and abnormal erythrocytic aggregation (16.5% vs 3%, p < 0.01). In these 3 groups the other studied parameters (Lp(a), platelet aggregation, cryoglobulin, cryofibrinogen, antinuclear antibodies, anticytoplasm antibodies, plasma and urine immunoelectrophoresis, protein C, protein S, antithrombin III, plasminogen) were not different from levels observed in normal subjects. CONCLUSION: An extensive biological analysis, including plasma homocystein level, anticardiolipin antibodies, anti-beta 2 glycoprotein 1 antibodies and a study of the erythrocytic aggregation would appear to be of value in patients presenting recurrent arterial or venous thromboembolic events. Specific therapy can be applied in case of abnormal results continued anticoagulant therapy for anticardiolipin and anti-beta 2 glycoprotein 1 antibodies, and a vitamin therapy for increased homocysteinemia.

Adolescent↗
PubMed1996

Decrease in internal jugular endothelin levels after carotid cross-clamping during human carotid revascularization procedures.

Endothelin-1 (ETL-1), a peptide recently isolated from vascular endothelial cells, acts in cerebral arteries in vitro as a potent and long-lasting vasoconstrictor and has been implicated in the development of cerebral vasospasm. To ascertain whether this new vasoconstrictor has any effect on regulation of the cerebral circulation, we measured plasma ETL-1 concentrations in patients undergoing carotid revascularization and attempted to correlate the variations of venous and arterial plasma ETL-1 with the characteristics of the procedure, including cerebral vasospasm. We prospectively studied 11 patients undergoing a total of 14 carotid surgical revascularization procedures (12 endarterectomies, 2 polytetrafluoroethylene bypass grafts from the common to the internal carotid arteries). Before carotid cross-clamping, blood samples were drawn from the internal jugular vein and the healthy common carotid artery proximal to the occlusive lesion to be treated. After endarterectomy, blood samples were withdrawn from the internal, external, and common carotid arteries. After the release of the last clamp, a final aliquot of blood was withdrawn from the internal jugular vein. After plasma extraction on a C2-ethyl microcolumn, plasma endothelin-like immunoreactivity was measured by means of radioimmunoassay with a polyclonal antibody. In 9 of the 11 patients, internal jugular vein ETL-1 concentration decreased statistically significantly after carotid artery cross-clamping (4.2 +/- 1.4 pg/ml vs. 3.9 +/- 1.1 pg/ml; p < 0.05). In the 2 patients in whom ETL-1 levels failed to drop, a shunt was used during the procedure in 1, and the other was the only patient who had an ipsilateral ischemic postoperative stroke. The decrease in internal jugular vein ETL-1 concentration failed to correlate with any of the cross-clamping times. The level of arterial blood ETL-1 remained steady in the common carotid artery before and after cross-clamping (4.5 +/- 1.5 pg/ml vs. 4.6 +/- 0.9 pg/ml). A small, nonsignificant decrease in ETL-1 level was noted in the external and internal carotid arteries after cross-clamping. The decrease in internal jugular vein ETL-1 levels may in part reflect a compensatory response to carotid artery cross-clamping, which could limit the reduction of local cerebral blood flow.

Blood Vessel Prosthesis↗
PubMed1996

In situ arterial allografting for aortoiliac graft infection: a 6-year experience.

Between October 1988 and May 1994, all aortoiliac graft infections seen in the authors' service were treated by in situ arterial allografting after resection of any infected graft or tissue. Some 83 consecutive cases were treated; there were 68 isolated primary prosthetic infections (82%) and 15 aortoenteric fistulae (18%). Emergency arterial allografting was performed in five cases (6%), elective allografting in 64 cases (77%) and elective allografting after emergency palliative revascularization using a temporary prosthetic graft in 14 cases (17%). Arterial allografts were harvested from cadavers as part of a programme to retrieve multiorgan transplant tissue. Fifteen patients (18%) died either intra- or postoperatively. Three died during the operation, one from septic shock and two from uncontrollable coagulopathy. Twelve patients died in the early postoperative period, from from septic shock, two from myocardial infarction, two from pneumonia, one from a pulmonary embolism, one from an intestinal infarction, one from recurrence of a duodenal fistula and one from disruption of the native aorta at the suture line. Three patients presented with an early complication directly related to the use of the allograft. Eleven early survivors of the series died during follow-up. Among these late deaths, only one could likely be allograft-related. In four patients, the aortic segment of the allograft was mildly dilated on late computed tomography scan; three were reoperated on for disruption of the extra-abdominal segment of their allograft. All four cases were managed with simple suture of the allograft or with the use of a new allograft. Fifteen patients exhibited 19 late occlusive lesions of their allograft; 17 of these lesions had to be treated either with transluminal angioplasty or with surgery using autogenous or allograft material. In all but one case, secondary patency could be achieved through these additional procedures. Late occlusive disease was more prevalent in the femoral segment of the allograft than in the iliac or, moreover, the aortic segment. There were no late amputations in this series.

Adult↗
PubMed1996

Arteries from human beings are less infectible by Staphylococcus aureus than polytetrafluoroethylene in an aortic dog model.

PURPOSE: Treatment of aortoiliac prosthetic graft infections includes the removal of the infected material and repeat revascularization if necessary. The risk of infection of the graft material used for the repeat revascularization has been the drawback of its use in situ except with autografts. Good results were obtained in this setting by use of in situ arterial allografts. The purpose of our study was to compare in vivo the infectibility of arteries used as allografts to the infectibility of commercially available prostheses. METHODS: Twelve dogs underwent thoracoabdominal aortic bypass with use of either an artery from a human being (n=6) or an expanded polytetrafluoroethylene (ePTFE) graft (n=6). One month later, bacteremia was produced with Staphylococcus aureus. One week after bacterial challenge, the animals were killed to recover the grafts. Each graft then underwent bacterial study. RESULTS: None of the arterial grafts grew bacteria, whereas four of the six ePTFE grafts (p < 0.05) did. In addition, none of the fragments of the arterial grafts grew bacteria, whereas 24 of the 60 ePTFE fragments (p < 0.01) did. CONCLUSION: Nonautologous arteries are less infectible than ePTFE in vivo. This decreased infectibility makes the arterial allograft an appealing material when revascularization must be performed in a contaminated field.

Animals↗