Endotension after endovascular aneurysm repair: the Ancure experience.

PURPOSE: The expansion of aneurysms after endovascular repair is a consequence of persistent sac pressure, usually resulting from an endoleak. Several authors have suggested that sac expansion can occur even in the absence of endoleak, referring to this phenomenon as endotension. This study undertakes a review of the largest US endograft trial data to better define the significance of aneurysm expansion in the absence of endoleak. METHODS: The core laboratory imaging database from the Ancure (Guidant) endovascular graft Phase I and Phase II trials approved by the Food and Drug Administration was reviewed with attention to aneurysm size and endoleak. Aneurysm size was measured with standardized two-dimensional computed tomography (CT) scan at the area of largest initial aneurysm diameter. Endoleak was detected with CT scans, color duplex ultrasound scans, and angiography in selected cases. Patients were evaluated at baseline, 3 months, 6 months, 12 months, and every 12 months thereafter. An endograft was classified as leaking if any endoleak was detected with any modality at any time point. RESULTS: A total of 658 patients were entered into these protocols and the data submitted to the core laboratory. A control group of 120 conventional aortic patients and a group of 62 without baseline CT data were excluded from further analysis. Of the remaining 476 patients, 144 (60 tube, 60 bifurcated, and 24 mono-iliac) were free of endoleak at all intervals and had baseline CT measurements to allow comparison. Overall, the average size decrease in this nonleaking group was 9.9 +/- 9.4 mm (range, -50.6-11.1 mm) at a mean follow-up of 23.3 months. Evaluation for overall aneurysm expansion revealed 17 patients who had an increase of 2.3 +/- 2.9 mm (range, 0.3-11.1 mm) at a mean follow-up of 14.1 months. Only two patients without evidence of endoleak exhibited growth of more than 5 mm at maximum follow-up (7.6 mm at 12 months and 11.1 mm at 36 months). Additional analysis of sealed endoleaks and late endoleaks failed to demonstrate any group with expansion in the absence of detectable endoleak. CONCLUSIONS: Endotension appears to be rare in this large series of prospectively evaluated endografts. From this review, endotension seems more likely to represent missed endoleak than true aneurysm expansion in the absence of perigraft flow.

The efficacy of laparoscopy in acute cholecystitis.

OBJECTIVE: To evaluate the role of laparoscopic cholecystectomy in acute cholecystitis and establish the outcomes of this treatment modality at North Oakland Medical Centers. METHODS: This was a retrospective analysis over a three-year period (January 1, 1994 to December 31, 1996), performed at a University-affiliated urban teaching hospital, North Oakland Medical Centers, Pontiac, Michigan. Five hundred and fifty-seven patients underwent surgical treatment for gallbladder disease; 88 patients had acute cholecystitis, and 469 patients had chronic cholecystitis. Acute cholecystitis patients underwent surgery within 72 hours of the onset of symptoms; the patient's selection for laparoscopic cholecystectomy or open cholecystectomy depended on severity of disease, co-morbid factors and surgeon's preference. The parameters of age, gender, operating (OR) time, length of stay, complications, conversion rates from laparoscopic cholecystectomy to open cholecystectomy, and cost were compared in patients who underwent laparoscopic cholecystectomy and/or open cholecystectomy. RESULTS: Patients chosen to undergo laparoscopic cholecystectomy for acute cholecystitis tended to be younger females. Patients treated with laparoscopic cholecystectomy for acute cholecystitis had shorter OR times and LOS compared to patients treated with open cholecystectomy for acute cholecystitis. Conversion rates (CR) were 22% in acute cholecystitis and 5.5% in chronic cholecystitis during the study period; CR diminished considerably between the first and third year. Complications were also lower in patients who underwent laparoscopic cholecystectomy vs. open cholecystectomy. CONCLUSIONS: Laparoscopic cholecystectomy appears to be a reliable, safe, and cost-effective treatment modality for acute cholecystitis; however, the surgical approach should be cautionary because of the spectrum of potential technical hazards. CR is improving as surgeons gain experience.

Optimal revascularization of segmental pancreatic transplant.

Vascular anastomotic thrombosis is one of the most frequent complications after segmental transplantation of the pancreas (STP). We propose a new type of vascular anastomosis to reduce the rate of vascular thrombosis following STP. For this purpose we used double arterial-double venous anastomosis (DADVA). Four different types of vascular anastomosis used for STP were studied and compared. The rate of vascular anastomotic thrombosis was evaluated in correlation with the type of vascular anastomosis used. Traditional vascular anastomosis (TVA) was complicated by vascular thrombosis in 51.9% of cases. DADVA reduced rate of vascular thrombosis to 2.6% (P < 0.01).

Cyclic guanine monophosphate (cGMP) an intracellular mediator of cavernosal smooth muscle relaxation following penile vascular surgery.

BACKGROUND: We describe a new surgical method for treatment of male impotence. This procedure allows preservation of erectile tissues and avoids the need for implantable devices. It was demonstrated, that after this procedure sustained and reproducible erections were feasible. The role of cyclic guanine monophosphate (cGMP) in generation of erection following this procedure was studied. METHODS: Concentration of cGMP in erectile tissues was studied in the chronic canine experimental model. cGMP measurements were obtained using enzymeimmunoassay method. RESULTS: It was detected that the process of erection was accompanied with increased concentration of cGMP in the involved erectile structures (from 39.59 +/- 8.95 and 39.39 +/- 8.54 pm/g to 78.67 +/- 24.05 and 81.62 +/- 18.80 pm/g respectively with p = 0.0001). Concentration of cGMP did not change in the control (from 41.14 +/- 5.38 to 39.26 +/- 7.59 pm/g with p = 0.4568). CONCLUSION: It can be concluded, that proposed new surgical procedure causes erection not by simple distention of erectile tissue sinuses by arterial blood. Arterial blood inflow is accompanied by activation of intracellular mechanisms responsible for smooth muscle relaxation in erectile tissues. Normal values of cGMP concentration in canine erectile tissues are also reported.

Blood flow in the pancreatic segment before and after transplantation.

BACKGROUND: Blood flow in the pancreas before and after transplantation has not been studied sufficiently. Blood flow in the pancreatic transplant as a function of type vascular anastomosis used has not been explored. AIM: The objective of our study was to study blood flow in the intact pancreas prior to harvesting and at different time periods after transplantation. Two different types of vascular anastomosis were used for segmental transplantation of the pancreas. Blood flow in the transplanted pancreas was compared in this two experimental groups. METHODS: Study was conducted on 61 mongrel dogs. Autotransplantation of a pancreatic segment was performed to the left iliac vessels. There were two randomized experimental groups. In the first group (26 animals) traditional vascular anastomosis was used to revascularize pancreatic graft. Proximal end of splenic artery was anastomosed to iliac artery in "end to side" manner. Portal end of splenic vein was anastomosed to iliac vein in "end to side" manner as well. Splenic ends of splenic artery and vein were ligated. In the second group (35 animals) double arterial double venous anastomosis was used. For this purpose, after completing traditional vascular anastomosis, second arterial anastomosis was created distal to the first one between distal end of splenic artery and iliac artery in "end to side" fashion. Second venous anastomosis was performed distal to the first one between splenic end of splenic vein and iliac vein in "end to side" fashion. Blood flow in the pancreatic segment was measured using direct blood flow measurement method and electromagnetic flowmetry. After transplantation of pancreatic segment, blood flow was measured in the pancreatic graft 3 min, 1 h, 1 and 6 months following transplantation. RESULTS: Blood flow in the pancreas before harvesting was 0.69 +/- 0.01 ml/min/g. Blood flow in the pancreatic transplant in traditional vascular anastomosis group was higher than blood flow in the normal pancreas (1.13 +/- 0.05 ml/min/g after one month and 1.00 +/- 0.05 ml/min/g after six months (p < 0.01)). Blood flow in the double arterial double venous anastomosis group was not statistically significantly different from blood flow in the normal pancreas at 1 and 6 months after transplantation (0.70 +/- 0.02 and 0.67 +/- 0.02 ml/min/g accordingly). CONCLUSION: Double arterial double venous anastomosis provided more physiological blood flow to the graft, than traditional vascular anastomosis.

Serum levels of interleukin 1 and tumor necrosis factor alpha correlate with peritoneal adhesion grades in humans after major abdominal surgery.

Peritoneal adhesions are a leading cause of potential morbidity and mortality. We undertook this prospective study to determine the clinical relevance of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) levels as biological markers for peritoneal adhesion formation in humans. Fifteen patients who had previous colectomies and were undergoing re-exploration for an elective vascular procedure were studied. Blood samples were collected from each patient preoperatively and 30 minutes after the abdominal incision was made. Serum levels of IL-1 and TNF-alpha were determined using enzyme-linked immunosorbent assay kits. Adhesions were graded using an adhesion scale of 0 (none), 1 (mild), 2 (moderate), and 3 (extensive, dense). Preoperative levels of IL-1 and TNF-alpha did not differ significantly among all patients (IL-1 level was 60 +/- 14 pg/mL, and TNF-alpha level was 45 +/- 11 pg/mL; mean +/- standard deviation). Significant correlation was observed between grades of adhesions and early intraoperative levels of IL-1 [101 +/- 36 pg/mL for grade 1 (n = 8) vs 298 +/- 73 pg/mL for grade 3 (n = 6); P < 0.01] and TNF-alpha (88 +/- 23 pg/mL for grade 1 vs 261 +/- 88 mL for grade 3; P < 0.02). We conclude that early elevations of IL-1 and TNF-alpha are reliable biological markers for postoperative adhesions in humans. Studies utilizing cytokines antibodies to these markers may further elucidate the efficacy of this method for prevention of peritoneal adhesions.

Arteriovenous fistula combined with basal external penile compression: a new cure for male impotence.

We describe here a new procedure designed to enable reproducible sustained erection in a canine model. In 10 dogs, an end-to-side arteriovenous fistula was created between the inferior epigastric artery and deep dorsal vein. A chronic skin tunnel was created at the penile base. Blood flow, intracavernosal pressure and intraspongiosal pressure and blood gases were measured initially and 3 months later. Cuff application for 30 minutes was used daily. At 3 months, animals were sacrificed and biopsies obtained. Physiologic and histological parameters of erectile structures remained unchanged. Intracavernosal and intraspongiosal pressures increased to 33.7 +/- 6.7 mm Hg and 25.3 +/- 12.2 mm Hg (from 8.0 +/- 2.9 and 6.0 +/- 3.6 mm Hg) after cuff application. We conclude that sustained erections are feasible. This procedure appears safe for human trials.

Effects of interleukin-6 and its neutralizing antibodies on peritoneal adhesion formation and wound healing.

This study investigates the effects of preoperative IV administration of IL-6 and anti IL-6 on peritoneal adhesion formation and wound healing. Thirty-six male Sprague-Dawley rats (350-400 mg) were divided into three groups: control (group 1); IL-6 (group 2); and anti IL-6 (group 3). Under sterile conditions, all rats underwent a midline laparotomy. Ten cm2 of cecal serosa was abraded, the cecum further irritated with 0.1 ml of 70 per cent alcohol, and the incision closed in layers. At 3 weeks, peritoneal adhesions were graded using a score of 0 (none) to 3 (extensive, dense). Skin samples from incisional sites were examined tensiometrically (true stress and true strain), biochemically (collagen content), and histologically. Adhesion formation score was significantly increased in IL-6 group (2.78 +/- 0.44, Mean +/- SD) and decreased in anti IL-6 group (1.40 +/- 0.52) compared to control (2.00 +/- 0.50). (P < 0.03 by Kruskal Wallis test). There was no significant difference in true stress, true strain, and collagen content between the two treatment groups and controls at the 0.05 level by ANOVA. Histological analysis showed higher number of inflammatory cells and fibroblasts in IL-6 treated groups. We conclude that IL-6 plays a major role in peritoneal adhesion formation. Selective immunosuppression, using IL-6 neutralizing antibodies preoperatively, leads to a reduction of such adhesion formation without a significant effect on wound healing.