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Biomedical subjects

B Marty

Publications and source records attributed to B Marty.

At least 37 records · Page 2Linked to original sources
PubMed1998

Endovascular treatment of a ruptured lumbar artery aneurysm: case report and review of the literature.

Lumbar artery aneurysms are uncommon lesions that usually present as pseudoaneurysms secondary to vessel injury. Despite their small size and retroperitoneal location, these lesions are potentially lethal once they rupture. This report describes a ruptured lumbar artery aneurysm which was successfully treated in a minimally invasive fashion. The diagnosis was suggested by computed tomography scan and confirmed with angiography. Successful treatment consisted of placing intravascular metallic coils into the lumbar artery. The literature contains only seven previous reports of ruptured lumbar artery aneurysms and these were managed either operatively or via an endovascular approach. Based upon the outcome of all reported cases, we believe that coil embolization of lumbar artery aneurysms following diagnostic angiography is an appropriate and effective mean of treating these lesions.

Aged↗
PubMed1998

Endoleak after endovascular graft repair of experimental aortic aneurysms: does coil embolization with angiographic "seal" lower intraaneurysmal pressure?

PURPOSE: To investigate the relation between endoleaks and intraaneurysmal pressure (IAP) and the effect of coil embolization in the management of endoleaks. METHODS: The infrarenal aorta of a dog (n = 15) was replaced by a polytetrafluoroethylene aneurysm containing a pressure transducer. Group I (n = 4) had untreated aneurysms. Group II (n = 4) had endovascularly excluded aneurysms without an endoleak. Group III (n = 7) had aneurysms excluded by means of grafts with a defect that represented the source of an endoleak. After 4 weeks of follow-up study, the endoleaks in group III dogs were subjected to coil embolization. Systolic IAP was measured daily and expressed as a ratio of systolic blood pressure obtained from a forelimb cuff. Arteriography, duplex ultrasonography, and spiral contrast computed tomography were performed to evaluate endoleaks. RESULTS: In group I, the LAP remained close to systolic blood pressure (ratio of 0.96 +/- 0.06), whereas in group II the IAP ratio showed a decline to 0.34 +/- 0.16 (p = 0.0009 group I versus II). After an initial decrease, the IAP ratio in group III stabilized at 0.75 +/- 0.18 (p = 0.003, group II versus III). Aneurysms with an endoleak remained pulsatile with a pulse pressure of 30 +/- 16 mm Hg, which was less than that of untreated aneurysms (62 +/- 15 mm Hg; p < 0.0001 group I versus III). Arteriography and computed tomography revealed "sealing" of endoleaks after coil embolization, but IAP ratio did not decrease (0.76 +/- 0.14) after coil embolization. CONCLUSIONS: Incomplete endovascular aneurysm exclusion caused by an endoleak fails to reduce IAP ratio and may subject the aneurysm to a continued risk for rupture. Although coil embolization resulted in angiographic and computed tomographic sealing, it failed to reduce IAP ratio.

Aneurysm, False↗
PubMed1998

Exclusion of lumbar arteries by aortic endovascular grafts: can angiography demonstrate sealing characteristics?

BACKGROUND: This study evaluates sealing characteristics of two designs of endovascular grafts by angiographic demonstration of exclusion of porcine lumbar arteries. METHODS: 6 endovascular grafts (3 self-expandable with integrated polyurethane wall versus 3 nitinol structures covered with polyester fabric) were implanted in 6 porcine aortae. Perfusion of lumbar arteries was assessed by angiography after implantation and by angiography and dissection at graft explantation after 4 +/- 2 months. Tissue healing was evaluated by light and scanning electron microscopy. RESULTS: Immediate exclusion of the lumbar arteries was achieved in 14/31 vessels (12 by polyurethane grafts and 2 by polyester grafts, p < 0.001). Follow-up angiography and dissection at explantation revealed perfusion of 30/31 lumbar arteries with a collateral network in most cases. Another reason for reperfusion of initially excluded branches was distention of the polyurethane grafts with resulting shortening allowing reperfusion of 8 of the 31 originally covered branches. Histological examination revealed a complete neointimal lining and a tight contact between endovascular grafts and aorta. CONCLUSIONS: The immediate angiographic demonstration of exclusion of lumbar arteries predicts sealing characteristics of endovascular grafts. Later angiographic reappearance is due to development of a collateral network and possible shortening of self-expandable devices.

Animals↗
PubMed1997

Chronic intraaneurysmal pressure measurement: an experimental method for evaluating the effectiveness of endovascular aortic aneurysm exclusion.

PURPOSE: To evaluate and compare the intraaneurysmal pressure (IAP) after exclusion using two different endovascular grafts. METHODS: Eight mongrel dogs had a 3 x 3 cm polytetrafluoroethylene (PTFE) aneurysm sewn as an interposition graft of the infrarenal aorta. A pressure transducer implanted into the aneurysm wall permitted continuous electronic IAP monitoring. Four aneurysms were excluded with a transluminally placed endovascular graft made of a PTFE graft and two Palmaz stents (PTFE-EG), three were excluded with a tantalum-Dacron endovascular graft (TD-EG), and one was surgically treated with a standard PTFE graft (PTFE-Surg). The dogs were observed for 18 to 50 days (mean, 37.5 days) and were evaluated after surgery with duplex and spiral computed tomographic scans. RESULTS: All grafts successfully excluded the aneurysms without perigraft channels or leaks as documented by arteriogram and duplex and computed tomographic scans. The mean IAPs after repair with all PTFE-EGs were significantly lower (p < 0.001) than the mean systemic pressures. In addition, the mean IAP reduction was significantly greater (p < 0.005) in the PTFE-EG group than in the TD-EG group. CONCLUSIONS: Aneurysm exclusion with PTFE-EG significantly lowered IAP, did so significantly better than the TD-EG, and approached the IAP reduction obtained by standard repair. Such pressure reduction is necessary for effective protection against aneurysm rupture.

Animals↗
PubMed1997

Biventricular assist using a portable driver in combination with implanted devices: preliminary experience.

Left ventricular assist systems with portable drive units are increasingly used in the clinical setting. However, such systems usually are not suitable for right ventricular support, and therefore, in the case of biventricular heart failure, they must be combined with other support devices that require additional drive consoles. As a result, most of the benefits of the wearable drive units (early mobilization and outpatient care) are lost. This present study was performed to evaluate biventricular support with implanted assist devices and a portable DC/battery-powered driver (Thoratec TLC-II). Electronic control by nonvolatile RAM accessible via RS232 interface, internal backup emergency battery, and optional manual activation are additional features of this 6 kg biventricular drive unit. In 3 bovine experiments (body weight 70 +/- 5 kg) partial cardiopulmonary bypass (CPB) was established, and two ventricular assist devices were implanted into a preperitoneal pocket on each side after connection to the right atrium and the pulmonary artery and to the left atrium and aorta, respectively. After weaning the patient from CPB, activated coagulation time (ACT) was kept at greater than 180 s, and biventricular support with the portable driver was activated. After 10 min, mean device flow stabilized at 3.5 +/- 0 L/min and remained at that level throughout the ensuing 6 h (3.5 +/- 0.3 L/min; NS). The heart rate moved from 130 +/- 13 beats per minute (bpm) at the end of CPB to 116 +/- 13 bpm after 10 min of assist (p < 0.05). Right atrial pressure moved from 11 +/- 2 mm Hg at the end of CPB to 13 +/- 3 mm Hg after 10 min of assist (not significant [NS]). Mean pulmonary artery pressure was 18 +/- mm Hg at the end of CPB and 17 +/- 5 mm Hg after 10 min of assist (NS). Left atrial pressure was 10 +/- 1 mm Hg at the end of CPB and 13 +/- 3 mm Hg after 10 min of assist (NS). Mean aortic pressure was 73 +/- 11 mm Hg at the end of CPB and 77 +/- 3 mm Hg after 10 min of assist (NS). Mixed venous oxygen saturation increased from 49 +/- 9% at the end of CPB to 58 +/- 10% after 10 min of assist (p < 0.05). The portable drive unit that was tested provides adequate power to maintain significant biventricular support with implanted right and left assist devices. The configuration of batteries tested driving two ventricles provides independence for 60 min.

Animals↗
PubMed1997

[Reaction of the blood vessel wall to microporous endovascular prostheses].

BACKGROUND: Sealing endovascular prostheses enable transluminal exclusion of aneurysms, fistulas and arterial leakage. This study investigated the tissue response towards a newly developed microporous stent within the unaffected porcine aorta in respect to angiographic and histologic findings. METHODS: The device consisted of a self-expandable stent of wire filaments with integrated polyurethane. Under fluoroscopic guidance the stents (diameter 6 and 10 mm) were deployed into the infrarenal aorta of 3 animals. Follow-up was scheduled for 1 month. Radiographs and angiographies were performed before, immediately after stent deployment and before the explantation procedure. The grafts were examined by light microscopy, immunocytochemistry and both scanning and transmission electron microscopy. Quantitative analysis was performed in respect to the tissue layers and the amount of polyurethane and elastin. RESULTS: Angiographic findings revealed stable stent position and patency without luminal narrowing. The trombus-free luminal stent surface was 67%. The tissue response consisted in total tissue ingrowth through micropores forming an even neointimal lining (273 +/- 225 microns). Restricted to the polyurethane a moderate foreign body reaction of giant cells was observed. The luminal surface showed focal endothelialization (19 +/- 19%). The tunica media was diminished (from 767 +/- 146 microns to 312 +/- 132 microns, p = 0.0001). The amount of elastin of the tunica media underlying the stent did not decrease essentially (from 3.63 +/- 1.25% in normal aorta to 3.74 +/- 2.54%, p = 0.9221). The amount of polyurethane did not change in comparison to pre-implantation (19.4 +/- 0.9% and 18.3 +/- 3.2%, respectively, p = 0.6098). CONCLUSIONS: Reliable stent anchorage, incorporation of the stents in the underlying artery and a thin neointimal lining with focal endothelialization were obtained after the implantation of the covered microporous self-expandable stents in the porcine model.

Animals↗
PubMed1996

Helium Isotopic Evidence for a Lower Mantle Component in Depleted Archean Komatiite

Archean magnesium-rich komatiites require hot and presumably deep mantle sources, but their trace-element composition and radiogenic isotope composition are similar to those of modern mid-ocean ridge basalts, which originate in the upper mantle. The isotopic composition of helium extracted by sequential crushing of fresh olivines separated from two Archean and one mid-Proterozoic komatiites varies over three orders of magnitude, between a radiogenic end-member rich in helium-4 and a component rich in helium-3. Such helium-3 enrichment suggests the presence of a lower mantle component in Archean komatiites.

Journal Article↗
PubMed1996

[Self-expanding endoluminal vascular prosthesis: experimental basis and in-vivo evaluation].

The present study investigates the physical properties and the in vivo application of in vivo of a self-expandable stent (Wallstent) with an incorporated sealant of microporous polyurethane. Measurements of diameter and length as a function axial load featured the data for the calculation for radial pressure. Porosity control was assessed in comparison to non gelatin-sealed knitted Dacron. 11 stents on a 11.5F catheter were inserted in the aorta of three minipigs and evaluated by pressure measurement and angiography. The coverage of the stent causes an increase of 0.05-0.1 bar of radial pressure. The graph received by calculations demonstrates the corresponding pressure for every given diameter of the stents. Porosity is similar to the Dacron graft. The patency-rate is 100%. Characteristics of this covered stents meet requirements of an endovascular prostheses. Exclusion of fistulas and small aneurysms seems to be possible.

Animals↗
PubMed1996

[Latex covering and mechanical analysis of balloon expandable stents].

To the moment a few stents of metallic coils or meshes are available with a sealing coverage. In the present study balloon-expandable stents have been covered with a thin layer of natural rubber latex. The physical properties of these impervious stents were compared to the conventional stents. The expansion, the loss of expansion and the deformity during and after balloon inflation have been analyzed. In the pressure zone of 4-6 bar the mechanical characteristics of the impervious stents were similar to the conventional stents. The stents were expanded at 100% related on the balloon diameter used for expansion. Additional pressure of 1 bar was necessary to expand the impervious stents. At balloon pressure below 4 bar the stents tied the balloons in the midzone. The impervious stents, expanded at 6, 8 and 10mm, underwent a loss of expansion of 10% after withdrawal of the balloons. Their configuration was barrel-shaped (4% central enlargement) due to the latex rubber, constricting the wire meshes at both ends. These preliminary results are encouraging and allow further investigations.

Biomechanical Phenomena↗
PubMed1996

[Subcapital humerus fracture with lesion of the axillary artery. 2 case reports and review of the literature].

Two cases of fractures of the humeral neck in association with an axillary artery injury are reported. Even now, there are still only 14 well-documented cases in the literature. Trauma, pattern of injuries and treatment are analyzed. The treatment is focused on preservation of hand function, which is more important than shoulder motion. Neurovascular damage causes an impairment of hand function. The priorities of treatment (reperfusion versus osteosynthesis) are dictated by the degree of ischemia. Long-term disability is determined by brachial plexus injury.

Aged↗
PubMed1996

[Morphology of abdominal aortic aneurysms with reference to endovascular blood vessel prosthesis].

The purpose of this report was to describe the frequency and morphology of infrarenal aortic aneurysms suitable for endovascular tube graft repair. Preoperative abdominal CT scans of 89 patients undergoing open tube graft repair were analyzed retrospectively by measurements of lengths and diameters of the aneurysms. The cases were divided into 3 separate groups: most suitable aneurysms with neck and cuff in 10% (9/89), aneurysms (59%, 52/89) with either a neck (92%) or a cuff (8%), and finally aneurysms without a neck or a cuff (31%, 28/89). The anatomically suitable aneurysms have a neck of 31 +/- 19 mm in length and 23 +/- 4 mm in diameter, a cuff of 17 +/- 6 mm in length and 25 +/- 6 mm in diameter. The aneurysms have a nearly saccular nature with a "saccular index" of 0.81 +/- 0.17, p = 0.009. It appears that 10% of aneurysms restricted to the infrarenal aortic segment fulfill all criterias for endovascular straight tube graft repair.

Aged↗
PubMed1995

[Experimental aortic aneurysm with endovascular technique].

We created a simple experimental aneurysm by a minimal operative trauma performing the balloon-dilatation and the rupture of the abdominal aorta of animals. The aorta of minipigs was dilated under angiographic control until the rupture became visible. The abdominal aorta and its branches were mapped out and measured. The angiographics were calculated using a planimetric device. The dilatation of the aorta was increased up to 3.5 times the initial diameter when rupture occurred. The microscopical examination showed lesions in all three layers of the vessel only at the rupture site and some focal lesions of the tunica intima. This one-step procedure of producing an experimental aneurysm is done using a low operative trauma and allows testing of endovascular systems using only one anaesthetic.

Aneurysm, Ruptured↗
PubMed1994

[Experimental retroperitoneoscopic lumbar sympathectomy].

The present study was designed to support the hypothesis that lumbar sympathectomy could be performed by minimal invasive surgery. In a porcine experiment, under laparoscopic vision control, a pneumoretroperitoneum was established through a direct retroperitoneal access for dissecting the retroperitoneal tissue layers and resecting the lumbar sympathetic trunc. The connective tissue septae were separated without any problems by blunt dissection under vision through the retroperitoneally inserted laparoscope. After exposure of the retroperitoneal organs and identification of specific landmarks, the resection of the lumbar sympathetic trunk was performed. We conclude that lumbar sympathectomy can be easily performed by minimal invasive surgery.

Animals↗
PubMed1994

[Bilateral anterior shoulder dislocation fracture after an epileptic seizure. A case report].

Fractures can occur during violent muscular violence such as occur in the course of epileptic seizures, though this is rare (0.3%). The proximal part of the humerus is most frequently affected. The typical lesion is bilateral posterior dislocation or fracture-dislocation. We present a rare case of bilateral anterior fracture-dislocation of the shoulder sustained as the result of an epileptic fit. The treatment given was open reduction, refixation of the anterior labrum and screw fixation of the fragments. A review of the literature revealed only 18 cases of bilateral anterior dislocations caused by convulsive seizures.

Bone Screws↗
PubMed1994

[Intramedullary nailing of the humerus shaft fracture].

The current retrospective study refers to 61 fractures and nonunions of the humeral shaft that were treated operatively between 1980 and 1990 in the Department of Surgery of the University of Zürich Medical School. All fractures were stabilized with thin noninterlocking AO tibial nails. The follow-up included 48/61 patients. The predominant fracture localization was the middle third of the humeral shaft (52 consecutive cases), and most of these fractures were of the simple transverse type A3 according to the AO classification (29 cases). The incidence of initial radial nerve palsy was 9/61 and that of postoperative palsy 1/61. No preoperative evaluation of radial nerve function was obtained in 4 multiply injured patients. Upon follow up, the function was found to have returned to normal in 8 patients. No infectious complications were observed. In 4/56 patients the final result was nonunion. In 41/48 a good result was obtained in terms of shoulder function. There were 7 patients (5 of them multiply injured) with poor shoulder motion with less than 100 degrees in abduction and anteversion.

Adolescent↗
PubMed1993

[Results of intramedullary nailing in humerus shaft fractures].

We present an analysis of a retrospective study of 61 humeral shaft fractures, stabilized with a thin AO tibial nail. All fractures were analysed according to the AO-classification. Follow-up included 48/61 patients and averaged 82 months. Local complications were postoperative radial nerve palsy in 1/61, infection in 0/61 and non-union in 4/56. A good result in shoulder function was obtained in 41/48 cases.

Adolescent↗
PubMed1992

[Isolated massive adrenal hemorrhage--an insidious complication in anticoagulation].

Massive bilateral adrenal hemorrhages are a rare complication of anticoagulant therapy. Among over 34,000 autopsies of adults we found six patients with such hemorrhages. Two were women and four men with a mean age of 81 years. They had been hospitalized and anticoagulated for various reasons. The hemorrhage occurred within ten days of anticoagulation, was always bilateral and massive and destroyed the adrenal cortex, thus leading to acute adreno-cortical insufficiency. The diagnosis in all patients was made only at autopsy. Main symptoms are abdominal pain, progressive hypotension, electrolyte disorders and disturbances of consciousness. In patient on anticoagulant therapy, these symptoms justify the suspicion of adrenal hemorrhage and the institution of lifesaving substitution therapy. Pathogenetically these hemorrhages are attributed to the combined effects of stress-induced adrenocortical tissue damage and increased bleeding tendency. The findings in our patients are compared with those of 83 patients from the literature.

Adrenal Cortex Diseases↗