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Biomedical subjects

J G Kretz

Publications and source records attributed to J G Kretz.

At least 19 recordsLinked to original sources
PubMed2001

Longitudinal ruptures of polyester knitted vascular prostheses.

AIM: The purpose of the study was the characterization of a type of rupture occurring on warp-knitted polyester vascular prostheses. MATERIALS AND METHODS: We studied 20 cases of warp-knitted polyester vascular prostheses that were explanted from humans that showed a longitudinal rupture as a part of a collaborative retrieval program. All the prostheses were immediately fixed in a 10% formaldehyde solution after their explantation in the operating room. The clinical data of these cases were recorded. The explants were photographed, washed to eliminate the surrounding tissues, and photographed again. The ruptures were characterized with macroscopic examination, optical stereomicroscopy, and scanning electron microscopy. RESULTS: The mean duration of implantation of the prostheses was 16.0 +/- 3.3 years (range, 9-20.7 years). The prostheses were Cooley Double Velour (n = 15) and Microvel Double Velour (n = 5). There were 16 aortobifemoral bypass grafts, 1 aorto-biiliac, 1 aorto-aortic, 1 iliofemoral, and 1 axillobifemoral. The longitudinal ruptures occurred on two specific parts of the prostheses: the guide line (6 cases) and the remeshing line (11 cases). In three cases both lines were affected. Scanning electron microscopy showed major degradation of the trilobar filaments of the velour and gradual ruptures of the flat filaments of the remeshing and guide lines. CONCLUSIONS: In this study, we have identified a specific mechanism of late (9-20 years) longitudinal rupture of knitted polyester prostheses consisting of degradation of the polyester filaments along the remeshing and guide lines that run the length of the graft.

Aorta, Abdominal↗
PubMed2000

Sealing of polyester prostheses with autologous fibrin glue and bone marrow.

The purpose of this study was to develop a sealing technique for polyester prosthetic grafts able to promote healing and reduce intimal hyperplasia. The porcine experimental model was aortoiliac bypass with a 6-mm diameter knitted polyester prosthetic graft implanted for 14 and 90 days. Animals were divided into three groups according to sealing technique as follows: pre-clotting with blood (group I, n = 12), sealing with autologous fibrin glue (group II, n = 14), and sealing with autologous fibrin glue and bone marrow cells (group III, n = 16). Feasibility and quality of sealing were evaluated by scanning electron microscopy prior to implantation and by assessment of blood loss. After removal, prostheses were cut into three segments comprising the proximal anastomosis, midsection, and distal anastomosis. Pieces were fixed, embedded in paraffin, and serially sectioned for histologic study. Histological study focused on the degree of stenosis and hyperplasia of the neointima of each prosthesis. The results of this short-term study indicate that sealing of polyester vascular prosthetic grafts with autologous fibrin glue and bone marrow cells is effective in reducing intimal hyperplasia. However further study will be needed to assess long-term healing.

Animals↗
PubMed1999

Impregnated polyester arterial prostheses: performance and prospects.

Impregnated polyester arterial prostheses have gained wide acceptance by most vascular surgery teams, probably because these prostheses are easy to use, without any preclotting. We offer here a synthesis of the main studies that have appraised the experimental and clinical performance of these prostheses, and we delineate their major prospects.

Animals↗
PubMed1999

Frame dislocation of body middle rings in endovascular stent tube grafts.

OBJECTIVES: To understand the cause, and propose a mechanism for frame dislocation in endovascular grafts. MATERIALS AND METHODS: Five tube grafts were explanted due to secondary distal leakage 15-21 months after operation. One bifurcated graft was removed during emergency operation after aortic rupture caused by secondary leakage. A second bifurcated graft was harvested from a patient with thrombotic occlusion of one limb, who died after transurethral prostatic resection. The inside of the grafts were examined endoscopically. The stent was inspected after removal of the fabric, broken ligatures were counted and examined by scanning electron microscopy. The fabric strength was tested by probe puncture. RESULTS: We found 17-44% of the stent ligatures of the body middle rings to be loose. The knots were intact. Degradation of the polyester textile was not observed. CONCLUSIONS: Continuous movements in the grafted aorta and blood pressure impose permanent stress to the stent frame and the polyester fabric resulting in morphological changes in the body middle ring of grafts. The clinical implications of the suture breakages are unknown although they may be related to distal secondary leakage in tube grafts.

Aortic Aneurysm, Abdominal↗
PubMed1999

Influence of crimping textile polyester vascular prostheses on the fluid flow kinetics. Groupe Européen de Recherche sur les Prothèses appliquées à la Chirurgie Vasculaire.

OBJECTIVES: to characterise the impact of the crimping of polyester prostheses on the fluid flow kinetics. DESIGN: an experimental in vitro study. MATERIALS AND METHODS: we investigated four models of polyester vascular prostheses in a continuous laminar flow circuit. The flow velocity was 80 ml/s for all experiments. We studied two fluids of different viscosity within the circuit. The speed of the particles was measured by a laser Doppler anemometer 2 to 52 mm from the prosthetic interface. We first established a calibrated flow-velocity profile corresponding to the study of the support inside the circuit without any prosthesis. We measured the velocity profiles for each prosthesis corresponding to four crimp densities obtained by stretching the grafts. RESULTS: the crimping of PET textile prostheses led to a decrease of flow velocity especially closer to the prosthetic surface. The decrease of flow velocity was dependent on the model of prosthesis. This decrease of flow velocity is described by the following negative exponential law: DeltaV=a times b(-x)where (a) is the crimp density and (b) the fluid viscosity. CONCLUSIONS: flow velocity near a prosthetic surface is influenced by the morphology of the crimping. The impact of crimping on the flow velocity in a vascular prosthesis can be predicted by computer simulation models. This may provide the optimal shape of crimping for each prosthesis.

Blood Flow Velocity↗
PubMed1999

[Paraplegia secondary to surgery of the abdominal aorta].

We report the case of an 84 year-old man who suffered of paraplegia after surgery of an abdominal aortic aneurysm. The neurologic status did not improve during 5 years of follow-up. This complication is rare in light of the review of the literature. It is more frequent after emergency (1.4%) and redux (19%) surgery than after elective surgery (1.1%). Its mechanisms are anatomic (occlusion of the Adamkievitz artery and of the pelvic collateral arteries) and hemodynamic mechanisms (thromboembolism, low systemic tension, long supra-renal clamping). Since pre-operative aortography to detect anatomic variations is not realistic, its only prevention remains maintenance of intra-operative hemodynamic, systemic heparinization, and preservation of the pelvic collateral circulation.

Aged↗
PubMed1998

Rupture of an abdominal aortic aneurysm after endovascular graft placement and aneurysm size reduction.

Reduction in aneurysm size during the months after an endovascular graft placement generally is considered one of the criteria of success. We report the case of a patient with an abdominal aortic aneurysm rupture occurring 9 months after a bifurcated endovascular graft placement despite a greater than 45% reduction in size noted on contrast-enhanced computed tomography scan performed at 7 months. Biomaterial modifications of the stent and of the Dacron explanted stent-graft are analyzed.

Aortic Aneurysm, Abdominal↗
PubMed1998

Endothelin participates in increased circulating atrial natriuretic peptide early after human heart transplantation.

BACKGROUND: Hemodynamic improvement after heart transplantation is expected to normalize the neuroendocrine balance, but circulating atrial natriuretic peptide (ANP) remains elevated. Endothelin stimulates ANP secretion and its concentration increases after heart transplantation, suggesting a role for this peptide in the cardiovascular adaptative response to heart transplantation. METHODS: To investigate whether endothelin may induce ANP increase in heart transplant recipients, we monitored daily ANP, endothelin, and related hormonal, biologic, and hemodynamic parameters before and during the first week after either heart transplantation (n = 15) or coronary artery bypass grafting (n = 10). RESULTS: Surgery induced a transient secretory peak of arginine vasopressin and endothelin in both groups at day 1. Bypass grafting did not modify normal ANP (11.8 +/- 2.1 pmol/L), endothelin (2.4 +/- 0.3 pmol/L), renin activity (0.11 +/- 0.04 pmol/L/sec), or aldosterone (492 +/- 122 pmol/L) values. Heart transplantation normalized the renin-aldosterone axis, but the early decrease observed for ANP (from 27.2 +/- 4.8 to 21.14 +/- 1.4 pmol/L) was only partial and transient. Endothelin further increased (from 4.4 +/- 0.8 to 9.14 +/- 1.8 pmol/L; p < 0.01) after transplantation. Positive correlations were observed between endothelin, isoproterenol dose, creatinine, right atrial pressure, and ANP, but multiple correlation analysis showed the important role of endothelin (r = 0.69, p < 0.001). Cyclic guanosine monophosphate correlated with ANP (r = 0.65, p < 0.001). CONCLUSIONS: Elevated endothelin, suggesting vascular dysfunction, likely contributes to the ANP increase observed early after heart transplantation. Furthermore, ANP, through a cardiac endothelium feedback, may act in the maintenance of circulatory homeostasis in heart transplant recipients.

Adult↗
PubMed1998

Normal short-term renal response to acute volume expansion in heart transplant recipients: a role for atrial natriuretic peptide?

BACKGROUND: The breakdown of blood pressure and body fluid homeostasis observed in heart transplant (Htx) recipients may partly be due, as in heart failure, to a blunted renal response to elevated atrial natriuretic peptide (ANP). METHOD: This possibility was addressed through determination of the relationship between ANP, the urinary cyclic guanosine monophosphate (cGMP), a biologic marker of ANP renal activity, and the early renal responses to 10 mL/kg isotonic saline infusion over 30 minutes in 8 control subjects and 8 matched Htx recipients. RESULTS: Urine flow, natriuresis, and urinary cGMP excretion increased similarly in both groups, resulting in elimination of, respectively, 1/2 and 2/3 of the sodium and the water load during the experiment that lasted 4 hours and 30 minutes. Plasma renin and aldosterone decreases were similar in both groups. Elevated ANP further increased in Htx after saline infusion (from 19.5 +/- 3.7 to 33.8 +/- 5.6 pmol/L, P < .001). Plasma cGMP paralleled ANP in both groups (r = 0.81; P < .001). Significant correlations were observed between plasma ANP and urinary cGMP excretion (r = 0.48, P < .025 and r = 0.43, P < .05 in Htx recipients and control subjects) and between plasma ANP and urinary sodium excretion (r = 0.64, P < .001 in Htx recipients). CONCLUSION: In spite of a relative renal hyporesponsiveness to the cardiac hormone, with higher plasma ANP being not associated with increased renal excretions in Htx recipients, ANP is likely to participate in the appropriate short-term renal response to acute volume expansion in Htx recipients.

Aldosterone↗
PubMed1997

Albumin-impregnated prosthetic graft for infrarenal aortic replacement: effects on the incidence and volume of perioperative blood transfusion.

We retrospectively reviewed 290 cases in which an albumin-impregnated polyester prosthetic graft was used for surgical management of aortic bifurcation disease between November 1987 and December 1990. The purpose of this review was to determine the incidence and volume of blood transfusion and to evaluate the rate of patency and the incidence of infection achieved using this type of prosthesis. The indication for surgery was abdominal aortic aneurysm (AAA) in 218 cases (190 elective procedures and 28 emergency procedures) and occlusive disease of the aortic bifurcation (ODAB) in 72 cases. Mean follow-up was 25.5 +/- 13.4 months (range: 1 and 50 months). The incidence of blood transfusion for elective AAA and ODAB surgery was 30.2% and 32.3% intraoperatively, 21.3% and 12.9% postoperatively, and 40.4% and 42.6% overall. The mean number of red cell packs transfused for elective AAA and ODAB surgery was respectively 1 and 0.8 intraoperatively, 0.4 and 0.6 postoperatively, and 1.4 and 1 overall. No immediate or late graft infection prosthesis was observed in any patient in this series. Primary and secondary patency was 95.5% and 97.5% at 6 months with no graft thrombosis during further follow-up. The fact that use of an impregnated graft in management of aortic bifurcation disease was accompanied by a high incidence and volume of blood transfusion suggests that these grafts do not reduce perioperative blood loss. Use of an impregnated prosthesis had no effect on the rate of patency and the incidence infection.

Aged↗
PubMed1997

Clinical presentation and treatment options for mitral valve myxoma.

Myxomas rarely are located on the mitral valve. We report the case of a 44-year-old man operated on successfully with mitral valve conservation, which is the 21st case of mitral valve myxoma reported in the western literature. Among the cases reported in the literature, the diagnosis was made at the time of autopsy in 6 cases, with premortem heart failure in 1 case. A clinical diagnosis was made in 15 cases on the basis of the following symptoms: peripheral embolism in 9 cases, cardiac signs in 4 cases, and constitutional manifestations in 2 cases. The clinical presentation of mitral valve myxoma differs slightly from that of other cardiac myxomas in that it has a lower incidence of constitutional manifestations. The gold standard for noninvasive diagnosis and localization of cardiac myxomas is transesophageal echocardiography. It allows for the detection of early, small valvular tumors and may help to characterize better their location and echostructure, facilitating the choice of an optimal surgical approach through preoperative study of the integrity and mobility of the valve. Conservative operative treatment by resection of the area of implantation of the myxoma followed by suture repair of the valve and annuloplasty may be recommended as the most appropriate treatment option for this rare condition.

Adult↗
PubMed1997

The impact of knee joint flexion on infrainguinal vascular grafts: an angiographic study.

OBJECTIVES: To characterise the morphologic behaviour of infrainguinal vascular grafts during flexion of the knee. DESIGN: A prospective angiographic study. MATERIALS AND METHODS: In 64 infrainguinal bypass grafts, intravenous digital subtraction angiography was performed within the first postoperative week. Frontal and lateral projection angiograms with the knee joint extended and with a 80-90 degrees flexion were taken. The distal anastomosis of the bypass was performed below-knee in 49 cases (18 in situ veins, 8 reversed veins with an anatomic course, 2 reversed veins with an extra-anatomic course, 4 composite grafts, 15 synthetic grafts with an anatomic course (14 polytetrafluoroethylene (ePTFE), 1 polyurethane), and two synthetic grafts with an extra-anatomic course. Fifteen ePTFE prostheses were implanted in the above-knee position. RESULTS: Out of 64 cases a total of 16 grafts showed stenotic kinking during flexion: two of the 18 in situ vein grafts, four of the 12 reversed vein grafts implanted with an anatomic course, one of the two reversed vein grafts implanted in an extra-anatomic site, eight of the 15 synthetic grafts crossing the knee, 0 of the two extra-anatomic ePTFE grafts, and one of the 15 cases of above-knee femoropopliteal ePTFE grafts. CONCLUSIONS: Stenotic kinking due to knee flexion can affect all kinds of bypass grafts including vein grafts placed anatomically and above-knee prostheses.

Anastomosis, Surgical↗
PubMed1997

[An original case of simultaneous cardiac, pancreatic and renal transplantation. Results over 6 years].

Combined transplantation is actually performed on specific and rare indications. We are presenting here the results of a combined heart-kidney and pancreatic graft. It was performed in a patient presenting an idiopathic cardiomyopathy in end-stage failure and a post-diabetic nephropathy on dialysis. Today, organs function is quite satisfactory with a 6 year follow-up. Only one isolated heart rejection episode was observed at the 15th post-operative day. The patient has recovered a full-time professional activity at one year. This successful graft was obtained by an "homogeneous multiorgan approach" during all the pre-peri and postoperative time.

Adult↗
PubMed1997

[Carotid endarterectomy by eversion and reimplantation. Techniques and results].

Endarterectomy of the carotid bifurcation through a longitudinal arteriotomy of the common and internal carotid arteries followed by a direct closure is still accepted as the main surgical technique for carotid stenoses. However, this technique is complicated in about 10% of the cases by a restenosis. Mechanisms of myointimal hyperplasia leading to restenosis are not completely explained. The technique of eversion endarterectomy of the internal carotid artery has been said to be an alternate technique which could decrease the incidence of restenosis. We described the three main techniques of eversion endarterectomy and their results. The technique of eversion endarterectomy after proximal section of the internal carotid artery is the most frequently used. It allows to treat easily length excess of the internal carotid artery. Its results are good in terms of neurologic morbidity and mortality. However, randomized comparative studies are still required in order to determine its role on the incidence of restenosis despite the first encouraging results of first non comparative studies. The technique of eversion endarterectomy after distal section of the internal carotid artery has been proposed by Chevalier who reported also good short term results and no delayed restenosis.

Carotid Artery, Internal↗
PubMed1997

[Extra-popliteal localizations of adventitial cysts. Review of the literature].

Cystic adventitial disease is an uncommon vascular anomaly first described in 1947 in the external iliac artery. The preferential localization is the popliteal artery although other arteries and veins may also be involved though not always recognized. There have been 45 extra-popliteal localizations of adventitial cysts reported in the literature. Thirty cases involved an artery an 15 a vein. The iliofemoral axis, with 33 reported cases, is the preferential localization of these extra-popliteal adventitial cysts (including 22 arteries and 11 veins). All the other cases also involved a vessel near an articulation (knee, ankle, elbow, wrist). Despite a preferential popliteal arterial localization only one case involved the popliteal vein. The diagnosis is rarely made before surgery, probably because of the nonspecific clinical presentation. Ultrasonography should allow better recognition of these adventitial cysts, eliminating an aneurysm or a synovial cyst, and evidencing the localization of the cyst within the vessel wall.

Cysts↗