Treatment of pulmonary sequestrations by means of endovascular embolization: future or fashion?

Bronchopulmonary sequestration is a rare malformation of the lower respiratory tract. Several methods of treatment have been described since the first publication. We present two cases of female adult patients with bronchopulmonary sequestration. In the first patient an unsuccessful attempt to treat the bronchopulmonary sequestration by means of arterial embolization is described. She was subsequently treated by means of surgical resection, which was the primary treatment for the second patient. Although endovascular techniques are becoming promising, in our opinion surgical resection remains the unique treatment for bronchopulmonary sequestration.

Mid-term results of robot-assisted laparoscopic surgery for aortoiliac occlusive disease.

The aim of this study was to evaluate middle-term clinical results of robot-assisted laparoscopic surgery (RALS) to treat aortoiliac occlusive disease (AIOD). Between 2002 and 2007, 28 consecutive patients received robot-assisted laparoscopic aortobifemoral bypass grafting (n = 24) or aortoiliac endarterectomy (n = 4). Patients were followed prospectively. RALS could be completed successfully in 24 patients; conversion to open surgery was necessary in four patients (14%). Median operative time was 350 min. Median aortic clamping time was 70 min. Median hospital stay was five days. One patient died within 30 days. Non-lethal complications occurred in four patients (14%). Clinical symptoms improved in all patients. Primary and secondary limb-based patencies at 36 months were 89% and 91%, respectively. In conclusion, RALS is a feasible and durable technique for patients with AIOD. Although operative times are long, RALS allows rapid postoperative recovery.

Antioxidant-enriched enteral nutrition and immuno-inflammatory response after major gastrointestinal tract surgery.

Major surgery induces an immuno-inflammatory response accompanied by oxidative stress that may impair cellular function and delay recovery. The objective of the study was to investigate the effect of an enteral supplement, containing glutamine and antioxidants, on circulating levels of immuno-inflammatory markers after major gastrointestinal tract surgery. Patients (n 21) undergoing major gastrointestinal tract surgery were randomised in a single-centre, open-label study. The effects on circulating levels of immuno-inflammatory markers were determined on the day before surgery and on days 1, 3, 5 and 7 after surgery. Major gastrointestinal surgery increased IL-6, TNF receptor 55/60 (TNF-R55) and C-reactive protein (CRP). Surgery reduced human leucocyte antigen-DR (HLA-DR) expression on monocytes. CRP decrease was more pronounced in the first 7 d in the treatment group compared with the control group. In the treatment group, from the moment Module AOX was administered on day 1 after surgery, TNF receptor 75/80 (TNF-R75) level decreased until the third post-operative day and then stabilised, whereas in the control group the TNF-R75 level continued to increase. The results of the present pilot study suggest that enteral nutrition enriched with glutamine and antioxidants possibly moderates the immuno-inflammatory response (CRP, TNF-R75) after surgery.

Suture damage during robot-assisted vascular surgery: is it an issue?

BACKGROUND: Manipulation of sutures during endoscopic surgery could lead to damage of suture structure, supposedly resulting in loss of strength. Lack of tactile feedback in robotic surgical systems might increase this problem. The objective of this study is to evaluate suture strength after robotic manipulation and to determine which suture material is least susceptible to damage from robotic manipulation. METHODS: The da Vinci surgical system was used to manipulate sutures. Three different suture materials (Prolene, ePTFE, Ethibond) of 3 different sizes (3-0, 4-0, and 5-0) were tested. A total of 270 sutures were pulled on a Servohydraulic Universal Testing Machine. The frequency of breaks at a manipulation-point and the maximum applied force (N) before the suture broke were used for statistic analysis. RESULTS: No loss in strength was shown in the ePTFE sutures after manipulation, whereas both Prolene and Ethibond sutures showed a significant loss of strength. CONCLUSIONS: ePTFE sutures are least susceptible to robotic manipulations and are, therefore, to be considered as a material of first choice.

Modular branched endograft system for aortic aneurysm repair: evaluation in a human cadaver circulation model.

A circulation model was created in 6 nonaneurysmal human cadavers to evaluate the deliverability, deployment, and acute performance of a modular branched endograft system for treatment of aortic aneurysms containing essential branch vessels. Two fenestrations were created in an appropriately sized aortic main endograft. Under fluoroscopic guidance, the main endograft was advanced to the target site and the fenestrations were aligned with the ostia of the renal arteries. Branch grafts were placed through the fenestrations into the renal arteries. The outcome was evaluated by post implant angiography and autopsy. Eleven branch grafts were deployed at the target site. All targeted renal arteries showed good patency. At autopsy, all main endografts were adequately deployed, and 10 of 11 branch grafts were locked in place. In this model, deliverability and deployment of the modular branch graft system is feasible in a reliable, predictable, and timely fashion.

Direct videoscopic approach to the descending thoracic aorta for aortic arch endograft delivery: evaluation in a porcine model.

PURPOSE: To examine the feasibility of a direct videoscopic approach to the descending thoracic aorta for endograft delivery to the aortic arch. METHODS: A double purse-string suture was placed on the aorta of 3 pigs via a thoracoscopic approach. Subsequently, the aorta was cannulated in the center of the purse-string. A 22-F delivery catheter was advanced under fluoroscopic control over a guidewire via a trocar into the proximal aorta. After deployment of a tubular endograft, the catheter was withdrawn from the aorta while simultaneously tightening the purse-string suture, without aortic cross clamping. The outcome was evaluated by post implant angiography and autopsy results. RESULTS: The procedure was successfully completed in all animals, with a mean total procedure time of 126 minutes (range 118-137). Mean endograft implantation time from needle puncture to catheter extraction was 27 minutes (range 21-37). Hemostasis was obtained in all animals after withdrawal of the delivery catheter and tightening the purse-string suture. The mean blood loss was 143 mL (range 80-220). Autopsy proved all purse-string sutures to be adequately placed and all endografts deployed in the correct position. CONCLUSION: A direct videoscopic approach to the descending thoracic aorta proved a feasible technique for endograft delivery to the aortic arch in a porcine model.

Fenestrated and branched endografts: assessment of proximal aortic neck fixation.

PURPOSE: To investigate proximal fixation characteristics of different aortic endograft designs: a suprarenally placed fenestrated endograft, a modular branched endograft, an infrarenal endograft with suprarenal bare stent fixation, and the gold standard, a conventional hand-sewn anastomosis. METHODS: Ten human cadaveric aortas were obtained at autopsy and transected 20 mm below the renal arteries to mimic an infrarenal aneurysm neck. In random order, the infrarenal, fenestrated, and branched endografts were deployed into the aorta. Using a hydraulic material testing machine, longitudinal load was applied to the distal end of each endograft until migration occurred, thus defining the displacement force (DF). Subsequently, a hand-sewn infrarenal anastomosis was tested in a similar manner. RESULTS: The median DF was 4.67 N (3.82-6.37) for the infrarenal endograft, 9.17 N (8.03- 10.81) for the fenestrated endograft, and 16.95 N (14.78-19.67) for the branched endograft. The differences in DF between the infrarenal and fenestrated endografts and between the fenestrated and branched designs were statistically significant (both p=0.005). The median force to dislodge the graft from the conventional anastomosis was 89.16 N (71.24-105.23). CONCLUSIONS: Suprarenally placed endografts, especially with additional branch grafts, provide improved proximal fixation compared to an infrarenal endograft with suprarenal bare stent fixation. However, none of the tested endografts approached the optimal, time-proven fixation, the hand-sewn anastomosis.

The role of Kupffer cells after major liver surgery.

BACKGROUND: Kupffer cells (KCs) are the resident macrophages of the liver. KCs have an enormous endotoxin eliminating capacity. Endotoxins play an important role in the development of systemic complications after partial hepatectomy by activating KCs. The role of KCs and endotoxins after partial hepatectomy is investigated. METHODS: Wistar rats (n = 16, 250-275 g) were randomly assigned to have 1 mL dichloromethylene-diphosphonate (CL2MDP) or 1 mL NaCl 0.9% i.v. Forty-eight hours later, all rats received a two-thirds liver resection. Twenty-four hours later, rats received at random 50 microg/kg endotoxin (LPS) in 1 mL or 1 mL of NaCl 0.9% IV. The rats were killed 4 hours after LPS or SAL infusion. RESULTS: CL2MDP infusion resulted in a complete KC elimination. KC-depleted rats had the lowest mean arterial pressure, the highest heart and ventilatory rate after endotoxemia. All rats were able to maintain pH in normal ranges. The KC-depleted rats after partial hepatectomy had the lowest CO2 levels and the highest levels of lactate during endotoxemia. Oxygen levels were similar in all groups. Hepatic, pulmonary, and renal mRNA expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta were decreased in KC-depleted rats. Plasma levels of TNF-alpha were significantly decreased in KC-depleted rats. Furthermore, the highest influx of macrophages and polymorphonuclear cells in the lung and kidney were measured in KC-depleted rats during endotoxemia. CONCLUSIONS: Partial hepatectomy in KC-depleted rats result in a more pronounced endotoxin-mediated systemic inflammation and decreased synthesis of cytokines.

A temporary hemostatic valve in the short limb of a bifurcated stent-graft to facilitate endovascular repair of ruptured aortic aneurysm: experimental findings.

PURPOSE: To evaluate a homemade tricuspid valve placed in the short limb of a bifurcated aortic stent-graft to facilitate endovascular treatment of ruptured abdominal aortic aneurysms (AAA). METHODS: A valve consisting of 3 polytetrafluoroethylene cusps was constructed in the short limb of a bifurcated stent-graft. The endoprosthesis was placed into an in vitro circulation model with pulsatile flow. Angiography was performed before and after insertion of the second graft limb. RESULTS: Angiographically, there was complete occlusion of the short limb before and normal patency after deployment of the second graft limb. Cannulation of the short limb with a guidewire was performed without technical difficulty. CONCLUSIONS: Addition of a temporary hemostatic valve in the short limb of a bifurcated stent-graft can potentially reduce blood loss during endovascular treatment of ruptured AAAs.

Kupffer cell-depleted rats have a diminished acute-phase response following major liver resection.

Partial hepatectomy (PH)-induced Kupffer cell (KC) activation results in a rapid release of cytokines inducing the acute-phase response (APR). This study was done to evaluate the role of Kupffer cells (KCs) in the course of the APR following PH and a consecutive endotoxin challenge. KC depletion was performed in rats by i.v. administration of 1 mL liposome-encapsulated dichloromethylene diphosohonate (Cl2MDP). Control rats received 1 mL NaCl 0.9%. Forty-eight hours later, PH was performed. At 24 h after PH, rats were randomized to receive either 1 mL NaCl 0.9% (saline) or 50 microg/kg LPS i.v. in 1 mL. Animals were sacrificed at 4 h after LPS or saline infusion. The APR was determined by measuring hepatic gene expression of alpha 2-macroglobulin, alpha 1-acid glycoprotein, and IL-6 and expression of hepatic albumin. The APR was significantly depressed in KC-depleted rats. Despite increased IL-6 mRNA synthesis in response to low-dose LPS, no enhancement of acute-phase protein synthesis (APP) was found in KC-depleted rats. Hepatic failure was most profound in KC-depleted rats, as indicated by elevated plasma levels of liver transaminases and ammonia. We conclude that after PH, KC function in the remnant liver is important for the acute-phase reaction and reduces endotoxin-induced hepatocyte damage.

Carotid stent mobility with regard to head movements: in vitro analysis.

Given that considerable motion of the carotid artery is present during head movements, we hypothesized that a flexible stent with low torsion might be favorable to avoid stress imparted to the stent and carotid artery. Therefore, we evaluated the flexibility of different expanded carotid stents before and after deployment in a carotid artery in vitro. Subsequently, we evaluated torsion of the bare expanded stents. Five stents (Wallstent [Boston Scientific Corp., Natick, MA], Acculink [Guidant Corp., Indianapolis, IN], Precise [Cordis Corp., Johnson & Johnson Company, Warren, NJ], Carotid SE [Medtronic AVE, Santa Rosa, CA], and Protégé [EV3, Plymouth, MN]) were tested. Flexibility was determined using a three-point bend test recording the bending load (BL) in grams required to flex the stent 25 degrees. Increased BL implies decreased flexibility. Torsion was measured by recording the rotation load (RL) in grams required to rotate the stents 30 degrees along its axis. Increased RL implies increased torsion. In the bare expanded state, the median BL was 6 g (range 1-22 g). The BL increased to 38 g (range 20-41 g) after deployment in a carotid artery, with the Carotid SE (21 g) and Wallstent (36 g) showing significantly lower BL (p < .0001 and p = .0016, respectively). Overall, the RL was 11 g (range 1-76 g). Significantly higher RL was required to rotate the Wallstent (73 g) and Precise (20 g) stents (p < .0001). The flexibility of the currently used stents decreases after deployment in a carotid artery irrespective of its flexibility in the bare state. Two stents showed increased torsion compared with the other stents. Limitations in both flexibility and torsion might influence the long-term performance of carotid angioplasty stenting.