Jean-Georges Kretz

Late complication of a Greenfield filter associating caudal migration and perforation of the abdominal aorta by a ruptured strut

We report the case of a 67-year-old woman who was admitted for surgical removal of a Greenfield filter that had been inserted 7 years before because of recurrent deep vein thrombosis associated with pulmonary embolism. This complication appeared on a plain abdominal radiogram that showed a 7 cm distal migration of the filter, a 30-degree angulation, and rupture of a strut at the level of the hub. Computed tomography, aortography, and ascending cavography demonstrated that the inferior vena cava was perforated by the struts and that the ruptured strut had penetrated the infrarenal aorta. As demonstrated by scanning electron microscopy, the fracture was due to a structural defect of the strut at its insertion point within the hub, with no sign of corrosion. Energy-dispersive radiography analysis failed to demonstrate impurity in the metal composition.

Aortic Reimplantation of the Superior Mesenteric Artery for Atherosclerotic Lesions of the Visceral Arteries: Sixty Cases

We report the results of a series of patients who had isolated or associated reimplantation of the superior mesenteric artery directly into the infrarenal aorta. Between 1967 and 1988, a total of 91 revascularizations for atheromatous lesions of the visceral arteries were performed in 89 patients. The superior mesenteric artery was reconstructed in 87 instances, 60 of which were direct or indirect reimplantations into the juxtarenal aorta. The procedure was isolated in 51 cases, and associated with the revascularization of another visceral artery in nine cases. These 60 patients were divided into three groups: Group A—seven patients undergoing emergency operation for acute intestinal ischemia; Group B—30 patients operated upon for chronic intestinal angina; and Group C—22 asymptomatic patients who underwent prophylactic revascularization. Two patients died in the immediate postoperative period (3.5%). Although most of the 29 late deaths were due to vascular disorders, only one was secondary to intestinal infarction. Twenty-one patients followed had good functional results; six patients had relapse of abdominal pain. Three of these underwent repeat vevascularization of the superior mesenteric artery 12 days, 18 months, and 22 months, postoperatively. Follow-up ranged from six months to 18 years. Two patients were lost to follow-up. Overall actuarial survival at five years was 69.60±15%. In our experience, isolated reimplantation of the superior mesenteric artery on the anterior aspect of the infrarenal aorta is a simple and reliable technique which affords good long-term results.

Influence of the Textile Structure on the Degradation of Explanted Aortic Endoprostheses

OBJECTIVESnTo investigate mechanisms of textile failure in explanted human aortic endoprostheses.nnnMATERIALS AND METHODSnEndoprostheses (n31) underwent optical and scanning electron microscopy, filament dynamometry, and saturation index measurement.nnnRESULTSnThe macroscopic lesions observed in the Stentor and Vanguard devices were holes at the extremities of the stents and slipping of the warp yarns at the level of sutures or of the longitudinal seams. The macroscopic lesions observed in AneurX endoprostheses were holes, slipping of the warp yarns and ruptures of the ligatures. The macroscopic lesions observed in the two Talent endoprostheses were sections of fibers at the level of the suture holes and few areas lesions of wear, with sometimes holes at the contact of the stent extremities. Stentor, Vanguard and AneurX all demonstrated low saturation indexes of the fabric (44-59%) with an important anisotropy. Whereas the Talent endograft demonstrated a high index of saturation (124-131%) with a low anisotropy. We did not demonstrate significant polymer degradation in any of the endoprostheses.nnnCONCLUSIONSnIt is essential to take into account the saturation index to optimally choose a woven textile for the construction of an endoprosthesis since this property of the textile may contribute to explain the macroscopic lesions observed. We did not observe significant polymer degradation by filament dynamometry but further studies are needed to confirm these data.

Mechanisms of Rupture of Knitted Polyester Vascular Prostheses: An In vitro Analysis of Virgin Prostheses

OBJECTIVESnPrevious explant retrieval studies have shown ruptures occurring on the remeshing line and the guide line of two types of warp-knitted grafts. The aim of our study was to characterize the mechanisms these ruptures.nnnMATERIALS AND METHODSnWe performed an in vitro study of the mechanical and chemical characteristics of virgin prostheses. We studied 2 virgin polyester warp-knitted grafts models: the Cooley Double Velour and the Microvel Double Velour constructed by Meadox (USA), using the following techniques: characterization and de-knitting of the textile structure, circumferential tensile strength, filament dynamometry, critical dissolution time of the filaments and scanning electron microscopy.nnnRESULTSnBoth prostheses were constructed in the same way but the texturized yarns of the Cooley graft included twice as many filaments (54) than the Microvel (27). There was more adsorbed tension in the Cooley structure than in the Microvel. The circumferential tensile strength test demonstrated that the Cooley graft always ruptured on the remeshing line and the Microvel graft always ruptured at the interface between the remeshing line and the standard line. Filament dynamometry demonstrated a heterogeneous behavior of the filaments inside the yarns, mainly at the remeshing line of the Cooley graft (27.1 cN/tex +/- 11.5% versus 26.1 cN/tex +/- 2.2% for the guide line and 28 cN/tex +/- 6.7% for the standard knit). Critical dissolution time of the filaments was significantly lower for the Microvel grafts (2.5 sec versus 17.2 sec for the Cooley).nnnCONCLUSIONSnRupture of knitted polyester prostheses are probably an underestimated phenomenon. They may occur at specific areas of the graft. Further studies are required to determine whether all grafts of this type are at risk.

Effect of chronic pre-treatment with angiotensin converting enzyme inhibition on skeletal muscle mitochondrial recovery after ischemia/reperfusion

Impaired skeletal muscle energetic participates in peripheral arterial disease (PAD) patient’s morbidity and mortality. Angiotensin converting enzyme inhibition (ACEi), cornerstone for pharmacologic risk factor management in PAD patients, might also be interesting by protecting skeletal muscle energetic. We therefore determined whether chronic ACEi might reduce ischemia‐induced mitochondrial respiratory chain dysfunction in the frequent setting of hindlimb ischemia–reperfusion. Ischemic legs of rats submitted to 5u2003h ischemia induced by a rubber band tourniquet applied on the root of the hindlimb followed by reperfusion without (IR, nu2003=u200311) or after ACEi (nu2003=u200314; captopril 40u2003mg/kg per day during 28u2003days before surgery) were studied and compared to that of sham‐operated animals (nu2003=u200311). The effect of ACEi on the non‐ischemic contralateral leg was also determined in the ACEi group. Maximal oxidative capacities (Vmax) and complexes I, II and IV activities of the mitochondrial respiratory chain of the gastrocnemius muscle were determined using glutamate–malate, succinate and TMPD–ascorbate substrates. Arterial blood pressure was significantly decreased after ACEi (124u2003±u20032.8 vs. 108u2003±u20034.19u2003mmHg; Pu2003=u20030.01). Ischemia–reperfusion reduced Vmax (4.4u2003±u20030.4 vs. 8.7u2003±u20030.5u2003μmol O2/min/g dry weight, −49%, Pu2003<u20030.001), affecting mitochondrial complexes I, II and IV activities. ACEi failed to modulate ischemia‐induced dysfunction (Vmax 5.1u2003±u20030.7u2003μmol O2/min/g dry weight) or the non‐ischemic contralateral muscle respiratory rate. Ischemia–reperfusion significantly impaired the mitochondrial respiratory chain I, II and IV complexes of skeletal muscle. Pharmacologic pre‐treatment with ACEi did not prevent or increase such alterations. Further studies might be useful to improve the pharmacologic conditioning of PAD patients needing arterial revascularization.

Autonomy Following Revascularisation in 80-year-old Patients with Critical Limb Ischaemia

OBJECTIVESnWe wanted to compare autonomy recovery after open and endovascular infrainguinal surgery for critical limb ischaemia (CLI) in octogenarians.nnnMATERIALS AND METHODSnWe performed a retrospective analysis of 167 consecutive CLI octogenarians who underwent infrainguinal open surgery (OS) or endovascular surgery (ES) between 2003 and 2008. OS and ES groups were compared in terms of autonomy level (Parker score), survival, limb salvage and patency rates.nnnRESULTSnPreoperative autonomy level was similar in both groups (OS nxa0=xa0109, ES nxa0=xa058) but 6-month postoperative autonomy level was better after ES (pxa0=xa00.01). There was a trend towards better survival after OS (74% at 1 year, 62% at 2 years, 32% at 4 years with OS and 68%, 50%, 17% respectively for ES pxa0=xa00.06), but no difference regarding limb salvage (91% at 1 year, 90% at 2 years, 89% at 4 years for OS and 94%, 87%, 86% respectively for ES, pxa0=xa00.939) and primary patency (76% at 1 year, 59% at 2 years, 50% at 4 years for OS and 82%, 75%, 32% respectively for ES, pxa0=xa00.467).nnnCONCLUSIONSnES is justified in CLI octogenarians, because it allows restoring a higher autonomy level, with limb salvage and patency rates comparable to OS.

Les tests mécaniques d'évaluation des prothèses vasculaires

Resume Les protheses vasculaires doivent respecter un ensemble de normes etablies par les commissions europeennes ou internationales pour pouvoir etre mises sur le marche. La connaissance de tous ces tests est indispensable au fabricant et permet au chirurgien de comparer impartialement les differentes protheses. Nous proposons de decrire les tests applicables aux protheses vasculaires tubulaires. Ces tests peuvent se regrouper en deux grandes familles. La premiere concerne la resistance a lusage (resistance aux sutures, resistances mecaniques, etc.). La seconde concerne les specifications utiles lors de limplantation (longueur utile, porosite, etancheite, etc.). Lanalyse de la description des normes montre quelles manquent souvent de precision, ce qui laisse une grande part a linterpretation. Dans dautres cas le parametre mesure est parfois difficile a determiner. Ceci est lie soit a lhistoire de la norme decrivant le processus de mesure du parametre, soit a une imprecision concernant le mode operatoire du test. La grandeur ainsi testee peut prendre des valeurs assez differentes dun laboratoire a lautre. Une analyse critique de ces tests nous conduit a proposer de nouvelles definitions pour certains parametres ce qui laisse une possibilite de perfectibilitea ces normes.

Les polymères synthétiques résorbables : caractéristiques et applications pour les prothèses artérielles

Impregnation of textile vascular prosthetics has been suggested in order to replace the precoagulation of the prosthetic at the time of implantation, as this technique is mandatory to make the prosthetic leak-proof. Currently these matrix are biologic and may potentially be responsible for infectious transmission. This infectious risk and the results of previous healing studies of impregnated prosthetics led us to take into account a further use of an essentially synthetic matrix. The main advantage of these matrix consisted in providing a reproducible degradation rate without submitting the patients to the not well known risk of infectious transmission due to their chemical synthesis. These matrices may provide a well-controlled variation of porosity of the prostheses after implantation. We conducted a literature review of the main synthetic resorbable polymers used as biomaterials which may also be potentially used for the impregnation of textile vascular prosthetics. We observed the main chemical characteristics and the absorption rate of these polymers.