[Role of the process of endothelium formation on the wall of the aortic prosthesis in protection against infection. Experimental study in dogs]

An experimental canine model was developed in order to evaluate the role of endothelialization of aortic prostheses for protection against septicemic infection and the utilization of 131I radiolabeled bacteria for vascular experimentation. Two groups of dogs were submitted to insertion of a dacron prosthesis segment in the abdominal aorta with subsequent infusion of inert 131I radiolabeled bacteria. In the first group ("A"), formed by five dogs, the infusion was made 30 minutes after the insertion of the prosthesis and in the second group ("B"), formed by four dogs, in a new surgery performed 12 weeks after. Fragments of the animals' prostheses and aortas were collected after 30 minutes of septicemia and analyzed by scan electron microscopy and submitted to reading of radioactivity uptake by a well-type counter. The microscopy recognized a complete endothelialization of the prostheses of dogs of group "B" 12 weeks after their insertion. Statistical analysis comparing fragments of non-endothelialized prostheses, of endothelialized prostheses and aortas demonstrated that the lower radioactivity uptake of the endothelialized prostheses in relation to non-endothelialized ones was significant (p = 0.0143) and that there was no significant statistical difference in uptake in the aortas and in endothelialized prosthesis (p = 0.3173). It was, therefore, concluded that prosthesis endothelialization fully protected them against septicemic infection; bacteremia contaminated all the non-endothelialized prostheses; there was no bacterial adhesion in the endothelialized prostheses and the use of bacteria labeled with radioisotope 131I is appropriate for the study of infections in vascular prosthetic devices.

[Surgical treatment of infections involving arterial prosthesis in aorto-femoral position]

This article is to evaluate the results of surgical treatment of aorto-femoral graft infections. The records of 20 patients with aorto-femoral graft infections were reviewed. The patients were submitted mostly to a combination of surgical procedures. They were: a) conservative treatment; b) partial removal of the infected graft and c) total removal of the infected graft. The removal of the prosthesis, partial or total, was followed by a new arterial reconstruction in some patients. The final treatment was: total removal of the infected graft in 11 (55%) patients, total removal plus arterial reconstruction in six, partial removal in two and partial removal plus arterial reconstruction in one. The results of treatment were presented as the survival rate and the effective palliation (patient alive, lower limbs preserved and infection cured). The survival rates after one month, 12, 24, 36 and 48 months were respectively: 80%, 60%, 53%, 42% and 27%. The effective palliation rates after one month and after 48 months were respectively 50% and 27%. The highest effective palliation rate was obtained when the infected prosthesis was removed and a new arterial reconstruction performed. We conclude that the treatment of choice of aorto-femoral graft infections seems to be the total removal of the graft followed by new arterial reconstruction.

[Infection involving arterial prosthesis: clinical picture, etiology, and predisposing factors]

Thirty patients were operated for arterial reconstruction with synthetic grafts. They presented one of the following complications: 1) prosthesis exposed by a cutaneous fistula; 2) prosthesis in communication with a hollow viscus; 3) prosthesis involved by pus; 4) positive culture of a fragment of the prosthesis or of the surrounding secretion. The clinical manifestations were cutaneous fistula in 21 patients (70%), external bleeding in 14 (47%), exposition of the prosthesis in five (17%), anastomotic aneurysm in five (17%), and enteric fistula in four (13%). The infection became evident during the first postoperative year in half of the patients. The most important agents of infection were staphyilococci and Gram negative bacteria.

[Vascular complications of the Ilizarov method]

Between 1987 and 1991, 209 patients were operated by the Ilizarov method in the Department of Orthopaedic and Traumatologic Surgery of the University of São Paulo Medical School. Five of them presented vascular complications during the treatment. All were adults treated for long bone pseudarthrosis. The vascular lesion occurred in the femoral superficial artery (one case), in the popliteal artery (one case), and in the posterior tibial artery (one case); in the remaining two patients it was not possible to determine the exact site of the lesion. The clinical manifestation of the vascular problem was bleeding at the cutaneous point of the Kirschner transfixation wires. Arteriography was done in all cases but its interpretation was difficult because of the presence of the external fixator. The treatment of the vascular complications was following: in the case of injury in the femoral artery, the external fixator was taken off and a by-pass with an inverted graft of the saphenous vein was made the same procedure was done in the popliteal artery but in this case it was not necessary to remove the external fixator; the remaining case with the lesion in the posterior tibial artery was treated by ligature. In two cases where the artery involved was not determined--one in the upper extremity with the external fixator applied to the femur--the bleeding stopped after the removal of wires.

[Arterial reconstruction of the iliofemoral segment by eversion endarterectomy]

From October 1985 to December 1988, 31 iliofemoral eversion endarterectomies were performed in 29 patients with arteriosclerosis. The surgical procedure was carried out for trophic lesions in 74% of the patients and for ischemic rest pain in the remaining 26%. In 11 operations the endarterectomy was associated with profundoplasty, and in eight with saphenous vein femoropopliteal bypass. There were six immediate failures, four of them submitted to successful reoperations, and two to above knee amputations. In cases with good immediate patency no complications occurred during the follow-up periods which ranged from one to 34 months. With one post-operative death the mortality rate was 3.2%. Two patients displayed later severe ischemic manifestations in the opposite limbs and were both submitted to the same type of operation with good result. It may be concluded that iliofemoral eversion endarterectomy is an appropriate alternative procedure to the aortoiliofemoral reconstruction surgery in patients with severe ischemia of the lower limbs.