Hybrid approach to emergent and urgent treatment of complex thoracoabdominal aortic pathology.

OBJECTIVES: The aim was to report a single center experience with hybrid procedures in the emergency treatment of patients with thoracoabdominal aortic pathology. Thoracoabdominal aortic aneurysm (TAAA) repair is primarily conducted by conventional surgery in the urgent and emergency setting. The role of hybrid procedures with stent graft coverage of the aorta and extra-anatomical debranching of the renovisceral arteries has so far not been defined in this context. METHODS: From 2007 to 2013 30 patients (21 males, 9 females) undergoing an emergent or urgent TAAA hybrid procedure were included in a data register. The mean aneurysm diameter was 72 mm. Etiology was atherosclerosis in 23 patients (76.7%) and aortic dissection in seven patients (23.3%). Nineteen patients (63.3%) required emergency surgery. In 11 cases (36.7%), surgery was indicated for symptomatic aneurysms. Mean follow-up was 16 months (range 1-72 months). RESULTS: The hybrid procedure was completed in all patients. Renovisceral revascularization was performed with a total of 101 grafts (25 to the celiac, 30 to the superior mesenteric, 25 to the right renal, and 21 to the left renal artery). The 30-day and 1-year primary graft patency was 97.3% and 95.3% respectively. A median of three stent grafts per patient was deployed. One patient underwent surgical intervention for early endoleak (3.3%). Three patients (10%) developed spinal ischemia with persistent paraplegia. Two patients (6.7%) required chronic hemodialysis. Thirty-day mortality reached 26.7% (N = 8), being 36.8% in emergency patients (7 of 19) and 9.1% in the urgent group (1 of 11 patients). The cumulative postoperative survival rate after 12 months was 57.8%. CONCLUSIONS: Hybrid procedures have the potential to be an alternative treatment option for complex thoracoabdominal pathology in the urgent and emergency setting. The procedure is readily available and enables adequate surgical repair with enduring results. Nevertheless it is still associated with significant mortality and morbidity.

[Routine subclavian revascularisation employing regional anaesthesia]. / Routinemäßige Subclavia-Revaskularisation in Regionalanästhesie.

INTRODUCTION: The increasing incidence of endovascular surgery on the thoracic aorta (TEVAR) is leading to an increased rate of subclavian-carotid transposition (SCT). Intentional overstenting of the left subclavian artery extends the proximal landing zone. If overstenting leads to a subclavian steal syndrome, vertebrobasilar insufficiency or if the risk of spinal ischaemia is present, SCT can safely be carried out with regional anaesthesia by means of a cervical block. MATERIALS AND METHODS: Since January 2010 regional anaesthesia was employed in 13 consecutive patients receiving an SCT in our clinic. Subclavian revascularisation was performed either as adjunct procedure for TEVAR or in patients with occlusive disease of the aortic arch. The clinical course was prospectively observed. RESULTS: In 62 % of the cases (n = 8) a transposition of the subclavian artery onto the common carotid artery was carried out. In 38 % of the cases (n = 5) an intraoperative decision was made to construct a carotid-subclavian bypass. In 30 % (n = 4) of the cases a conversion from cervical block to general anaesthesia was necessary. All reconstructions proved to be patent at follow-up. CONCLUSION: Subclavian-carotid transposition under regional anaesthesia is safe and technically feasible if occlusion of the subclavian artery by thoracic stentgraft or stenosis has occurred. The technique employing regional anaesthesia can, therefore, also be offered to patients with increased risk for complications due to general anaesthesia.

Strain measurement of abdominal aortic aneurysm with real-time 3D ultrasound speckle tracking.

OBJECTIVES: Abdominal aortic aneurysm rupture is caused by mechanical vascular tissue failure. Although mechanical properties within the aneurysm vary, currently available ultrasound methods assess only one cross-sectional segment of the aorta. This study aims to establish real-time 3-dimensional (3D) speckle tracking ultrasound to explore local displacement and strain parameters of the whole abdominal aortic aneurysm. MATERIALS AND METHODS: Validation was performed on a silicone aneurysm model, perfused in a pulsatile artificial circulatory system. Wall motion of the silicone model was measured simultaneously with a commercial real-time 3D speckle tracking ultrasound system and either with laser-scan micrometry or with video photogrammetry. After validation, 3D ultrasound data were collected from abdominal aortic aneurysms of five patients and displacement and strain parameters were analysed. RESULTS: Displacement parameters measured in vitro by 3D ultrasound and laser scan micrometer or video analysis were significantly correlated at pulse pressures between 40 and 80 mmHg. Strong local differences in displacement and strain were identified within the aortic aneurysms of patients. CONCLUSION: Local wall strain of the whole abdominal aortic aneurysm can be analysed in vivo with real-time 3D ultrasound speckle tracking imaging, offering the prospect of individual non-invasive rupture risk analysis of abdominal aortic aneurysms.

Nutritional support after open liver resection: a systematic review.

BACKGROUND: Perioperative nutrition in patients with limited liver function after partial hepatic resection is still controversial. In particular, the significance of perioperative total enteral nutrition remains unresolved. The aim of this review is to investigate the impact of early postoperative total enteral nutrition on convalescence after partial liver resection. MATERIALS AND METHODS: In an internet-based Medline-Search (time course: 1960-08/2005) a total of five prospective, randomized controlled trials were found comparing the impact of enteral and parenteral nutrition after liver resection. After study validity had been established, a systematic review was undertaken (odds ratio, 95% confidence interval, p < 0.05 level of significance; Review Manager 4.2, The Cochrane Collaboration). Primary endpoints were complication rate (infection, organ malfunction) and mortality. Standardized immune parameters were also surveyed. RESULTS: Statistical analysis showed that enteral nutrition resulted in a significantly lower rate (p = 0.04) of wound infection and catheter-related complications than parenteral nutrition did. No statistically significant differences in mortality due to enteral or parenteral nutrition could be found. Patients receiving enteral nutrition showed better postoperative immune competence. CONCLUSION: Early enteral nutrition after liver resection is a safe procedure. Compared to parenteral nutrition it is associated with a decreased incidence of postoperative complications. Facing the inhomogeneity of these trials, especially in nutrition protocols and end points, this first systematic review stresses the need for an update of the importance of early enteral nutrition after liver resection within randomized controlled multicenter trials.

Insufflation profile and body position influence portal venous blood flow during pneumoperitoneum.

BACKGROUND: We investigated changes in portal venous blood flow (PVBF) during carbon dioxide (CO2) pneumoperitoneum to evaluate the effects of different insufflation profiles and body positions. METHODS: An established rat model was extended by implanting a portal vein flow probe that would enable us to measure PVBF for 60 min [t0-t60] in animals subjected to a CO2 pneumoperitoneum with an intraabdominal pressure (IAP) of 9 mmHg. Forty-eight male Sprague-Dawley rats were randomized into the following four experimental and two control groups: decompression group D1 ( n = 8), desufflation for 1 min every 14 min; decompression group D2 ( n = 8), desufflation for 5 min, after 27 min; position group P1 ( n = 8), 35 degrees head-up position; position group P2 ( n = 8), 35 degrees head-down position; negative control group C1 ( n = 8), no insufflation; positive control group C2 ( n = 8), constant IAP of 9 mmHg for 60 min. RESULTS: Pneumoperitoneum and body positions, respectively, reduced PVBF [t1-t60] significantly ( p < 0.001) by 32.0% C2, 32.8% D1, 31.1% D2, 40.8% P1, and 48.5% P2, as compared to PVBF at t0 in each group. There was a significant difference in PVBF reduction between P1 and P2 and also between C2 and both P1 and P2 ( p < 0.04). CONCLUSIONS: CO2 pneumoperitoneum reduces PVBF significantly (>30%). Extreme body positions (35 degrees tilt) significantly intensify PVBF reduction. PVBF reduction is significantly more dramatic in subjects placed in a 35 degrees head-down position. Short desufflation periods did not improve mean PVBF, but it may have beneficial immunological and oncological effects that warrant further investigation.

Transoesophageal echocardiography shows high risk of gas embolism during laparoscopic hepatic resection under carbon dioxide pneumoperitoneum.

BACKGROUND: The ultrasonically activated scalpel (UAS) enables safe and effective laparoscopic tissue dissection, making hepatic resection feasible. This study compared blood loss and risk of gas embolism using the UAS during open hepatic resection and laparoscopic hepatic resection. METHODS: Female pigs were divided into two groups for laparoscopic (n = 7) and open (n = 5) left hepatic lobectomy. The UAS was used for both tissue cutting and coagulation. Laparoscopic liver resection was performed under carbon dioxide pneumoperitoneum (intraperitoneal pressure 12 mmHg). During surgery animals were monitored haemodynamically by an arterial line and Swan-Ganz catheter. Two-dimensional transoesophageal echocardiography (2D-TEE) was used to detect gas emboli with special attention to the right atrium and ventricle. Gas emboli were graded according to size, and correlated with haemodynamic and blood gas data. RESULTS: During open and laparoscopic hepatic resection the UAS resulted in minimal blood loss and effective tissue dissection. No air embolism was seen during open surgery. With laparoscopic hepatic resection 2D-TEE revealed gas embolism in all animals. Gas embolism was accompanied by cardiac arrhythmia in four of seven animals. No direct correlation was observed between embolism episodes and blood gas variables. There were no deaths after episodes of embolization. A significant decrease in arterial partial pressure of oxygen was seen at the end of the laparoscopic procedure in all animals. CONCLUSION: The UAS causes minimal blood loss during both open and laparoscopic hepatic resection. Laparoscopic liver dissection under carbon dioxide pneumoperitoneum carries a high risk of gas embolism.

Effect of fibrin glue occlusion of the hepatobiliary tract on thioacetamide-induced liver failure.

BACKGROUND: Expression and activation of hepatocyte growth factor (HGF) is stimulated by a complex system of interacting proteins, with thrombin playing an initial role in this process. The impact of temporary occlusion of the hepatobiliary tract with fibrin glue (major component thrombin) on the HGF system in acute and chronic liver damage in a rat model was investigated. METHODS: Chronic liver damage was induced in 40 rats by daily intraperitoneal application of thioacetamide (100 mg/kg) for 14 days. After 7 days half of them received an injection of 0.2 mL fibrin glue into the hepatobiliary system. Daily intraperitoneal administration of thioacetamide continued for 7 consecutive days. The rats were then sacrificed for blood and tissue analysis. Acute liver failure was induced in 12 rats by intraperitoneal administration of a lethal dose of thioacetamide (500 mg/kg per day for 3 days) after an injection with 0.2 mL fibrin glue into their hepatobiliary tract. Survival rates and histological outcome were investigated and compared with control animals. RESULTS: Fibrin glue occluded rats showed significantly lower liver enzyme activities and serum levels of bilirubin, creatinine and urea nitrogen. Immunohistochemistry revealed a significant increase in c-met-, HGFalpha- and especially HGFbeta-positive cells. Rats subjected to a lethal dose of thioacetamide survived when fibrin glue was applied 24 hours prior to the toxic challenge. These animals showed normal liver structure and no clinical abnormalities. CONCLUSION: Fibrin glue occlusion of the hepatobiliary tract induces therapeutic and prophylactic effects on chronic and acute liver failure by stimulating the HGF system. Therefore, fibrin glue occlusion might be useful in treating toxic liver failure.

Cirrhosis serum induces a nitric oxide-associated vascular hyporeactivity of aortic segments from healthy rats in vitro.

OBJECTIVE: Arterial vasodilation with concomitant hyperdynamic circulation are common findings in liver cirrhosis. Nitric oxide acting at a local level has been suggested to be pathophysiologically relevant in this context. Several systemic factors in conjunction with nitric oxide might interfere with the observed phenomena. DESIGN: The study has been designed to demonstrate the influence of cirrhotic serum on the nitric oxide system and vascular contractility. METHODS: The contractile response of aortic segments from healthy rats was studied in vitro after incubation with serum of healthy and cirrhosis-induced rats (1 week, 2 weeks, 3 weeks and 4 weeks after bile duct ligation). A cumulative dose response curve to phenylephrine (10--10-4 mol) was established before and after incubation with nitric oxide synthesis blocker N(omega)-nitro-L-arginine, the more selective aminoguanidine (nitric oxide synthase [NOS]-2 inhibitor) and W7 (NOS-3 inhibitor). NOS-2 expression in incubated aortic rings was evaluated by Western blot analysis. RESULTS: A 4-hour incubation with serum of cirrhosis-induced rats reduced the maximum contractile response to phenylephrine to 66.8 +/- 9.1% after 1 week, 50.4 +/- 7.8% after 2 weeks, 43.2 +/- 2.8% after 3 weeks and 35 +/- 5.2% after 4 weeks of bile duct ligation. This reduction in the contractility response to phenylephrine was completely reversed by blocking nitric oxide synthesis with N(omega)-nitro-L-arginine and aminoguanidine, but not after W7. Incubation with cirrhotic serum induced NOS-2 expression in aortic rings. In Western blot analysis, the most intensive signal for NOS-2 protein was obtained in rings incubated with serum from rats 3 weeks and 4 weeks after induction of cirrhosis. CONCLUSIONS: Cirrhotic serum decreases the contractile response to phenylephrine even in an early stage of secondary cirrhosis. Reversibility of this effect after nitric oxide synthesis blockade suggests an induction of nitric oxide synthesis by systemic factors as a major point in vascular hyporeactivity to vasoconstrictors in cirrhosis.

Effect of insufflation gas and intraabdominal pressure on portal venous flow during pneumoperitoneum in the rat.

BACKGROUND: Carbon dioxide, the primary gas used to establish a pneumoperitoneum, causes numerous systemic effects related to cardiovascular function and acid-base balance. Therefore, the use of other gases, such as helium, has been proposed. Furthermore, the pneumoperitoneum itself, with the concomitant elevation of intraabdominal pressure, causes local and systemic effects that have been only partly elucidated. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters. METHODS: An established animal model (rat) of laparoscopic surgery was extended by implanting a periportal flow probe. Hemodynamics in the portal vein were then measured by transit-time ultrasonic flowmetry during increasing intraabdominal pressure (2-12 mmHg) caused by gas insufflation (carbon dioxide vs helium). RESULTS: The installation of the pneumoperitoneum with increasing intraperitoneal pressure led to a significant linear decrease in portal venous flow for both carbon dioxide and helium. At higher pressure levels (8-12 mmHg), portal blood flow was significantly lower (1.5-2.5-fold) during carbon dioxide pneumoperitoneum. An intraabdominal pressure of 8 mmHg caused a decrease to 38.2% of the initial flow (helium, 59.7%); whereas at 12 mmHg, portal flow was decreased to 16% (helium, 40.5%). CONCLUSION: Elevated intraabdominal pressure generated by the pneumoperitoneum results in a reduction of portal venous flow. This effect is significantly stronger during carbon dioxide insufflation. Portal flow reduction may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery.

[Robot-assisted laparoscopic cholecystectomy and fundoplication--initial experiences with the Da Vinci system]. / Roboterassistierte laparoskopische Cholecystektomie und Fundoplicatio--erste Erfahrungen mit dem Da-Vinci-System.

We report on our first five robot-assisted laparoscopic cholecystectomies and one fundoplication (Da Vinci system). No postoperative complications were observed. For the cholecystectomies (three elective and two acute cases) mean operation time was 1 h 35 min, and mean hospital stay was 5 days; for fundoplication the operation time was 2 h 15 min. The main advantages seem to be improved visualization by using a stereo camera und ease of precise dissection by micromechanical instruments directed by masterslaves from a distant console. The main disadvantage is the high cost. To fully evaluate the benefit for the patient, prospective clinical trials are warranted.

[The SOFA score in evaluating septic illnesses. Correlations with the MOD and APACHE II score]. / Der SOFA-Score in der Beurteilung septischer Krankheitsbilder. Beziehungen zu MOD- und APACHE-II-Score.

The SOFA score, a new system for patients with sepsis-related diseases, was introduced in 1994 by the "Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine." The purpose of this study was to compare the new SOFA score with the APACHE II and MOD scores. The data on 874 patients from a surgical intensive care unit in an university hospital were analyzed using commercially available software (SPSS for Windows, Version 7.5.2 and MS Excel '97). To compare the different scores, receiver-operating characteristics (ROC)--analyses were applied. The study demonstrated clear correlation between an elevated SOFA score and the mortality of the patients during their ICU stay (score 0-->mortality 0%, 1-->3.6%, 2-->22.5%, 3-->86.7%, respectively r = 0.445; P = 0.01). The ROC analyses of the APACHE II, the MOD and the SOFA scores were comparable (area under the curve: APACHE II 0.73, MOD 0.77, SOFA 0.71). In conclusion, the SOFA score is reliable and might be useful in the daily routine of an intensive care unit.

Markov cohort simulation study reveals evidence for sex-based risk difference in intensive care unit patients.

BACKGROUND: Despite great advances in intensive care medicine, sepsis still is the leading cause of death. Different strategies have been developed to file the patient data into scoring systems, primarily to predict the outcome. The Markov simulation-predominantly used in economic science to describe chains of events depending on and influencing each other-seems to be an interesting and new approach in analyzing the course of disease of critically ill patients in an intensive care unit (ICU). Using such a Markov model, this study analyzes data from 660 surgical ICU patients, 44 of whom died of sepsis. METHODS: A three-state Markov model (integrating sepsis, adult respiratory distress syndrome, and mortality) was constructed to describe the course of disease of critically ill patients in defined cycles and to develop the risk profile of different groups of patients. The model enables the comparison between age- and sex-related survival rates and shows the difference in life expectancy compared with an average untreated standard population. RESULTS: Women aged up to 30 years (G1F) show the best prognosis (mortality after 19 cycles 8.3%). On the contrary, the corresponding male group (G1M) demonstrates the worst outcome (mortality after 19 cycles 57.7 %). CONCLUSIONS: The findings of this study fit into the current discussion that female patients are better positioned to meet the challenge of sepsis.

Carbon dioxide pneumoperitoneum is associated with increased liver metastases in a rat model.

BACKGROUND: In patients with primary colorectal cancer, liver metastases are the most important indicators of prognosis and survival; the effect of laparoscopic surgery on the development of hepatic tumor spread is still largely unknown. METHODS: Thirty WAG/Rij rats were randomly divided into 3 operative groups for intraportal tumor cell inoculation: carbon dioxide pneumoperitoneum (group I, n = 10), gasless laparoscopy (group II, n = 10) and open laparotomy (group III, n = 10). The total operating time was 90 minutes with tumor cell injection (50,000 CC531 colon carcinoma cells/mL) performed 45 minutes after the start of the procedure. Hepatic tumor growth and the total tumor load were evaluated 28 days after surgery. RESULTS: Hepatic tumor growth and total tumor load were significantly reduced in the gasless laparoscopy group (group II) as compared with the carbon dioxide pneumoperitoneum group (group I) and the open laparotomy group (group III) (P < .05). No significant difference was found between the carbon dioxide and the open laparotomy groups. CONCLUSIONS: Insufflation of carbon dioxide may actually stimulate metastatic disease of the liver. Gasless laparoscopy seems to preserve hepatic resistance against tumor growth.

Portal venous flow during CO(2) pneumoperitoneum in the rat.

BACKGROUND: CO(2) gas insufflation is routinely used to extend the abdominal wall. The resulting pneumoperitoneum has a number of local and systemic effects on the organism. Portal blood flow, which plays an important role in hepatic function and cell-conveyed immune response, is one of the affected parameters. METHODS: An established animal model (rat) of laparoscopic surgery was modified by implanting a perivascular flow probe. Hemodynamics in the portal vein were then measured during increasing intraabdominal pressure generated by carbon dioxide insufflation. RESULTS: Using this technique, an adequate flowmetry of the portal vein was achieved in all animals. The creation of a CO(2) pneumoperitoneum with increasing intraabdominal pressure led to a linear decrease in portal venous flow. CONCLUSIONS: Elevated intraabdominal pressure caused by carbon dioxide insufflation may compromise hepatic function and cell-conveyed immune response during laparoscopic surgery.

Surgical strategies -- anastomosis or stoma, a second look -- when and why?

INTRODUCTION: The indication for performing a primary anastomosis or an intestinal stoma has to be confirmed or negated for every individual case of intestinal ischemia. DISCUSSION: In right-sided colonic emergency, primary anastomosis is possible except when associated with generalized peritonitis. In left-sided colonic ischemia and necrosis, delayed anastomosis is the preferred alternative. In ischemia following surgery for abdominal aortic aneurysms, primary anastomosis is contraindicated. In ischemia of the small bowel, an end-to-end anastomosis should be established whenever possible. CONCLUSION: In the case of intestinal ischemia, a second-look laparotomy is mandatory 24-48 h after initial surgery to ensure bowel viability. This second look should be performed regardless of the patient's postoperative clinical status. Laparoscopy has been successfully used for reexploration in intestinal ischemia, but one has to be aware of the present limitations of experience using this technique.

Endothelin-induced contraction of the portal vein in cirrhosis.

Endothelin (ET) is one of the most potent vasoconstrictors known so far. It has been proposed that the ET-induced contraction of hepatic stellate cells (Ito, endothelial cells) is an important mechanism for the development of portal hypertension. The purpose of this study was to investigate in an in vitro model whether ET causes a contraction of the portal vein which can contribute to portal hypertension in cirrhosis. Portal veins from normal and cirrhotic rats were used for experiments. Measurements were performed in vitro for cumulative concentrations of ET-1 and ET-3 (1, 5, 10, 50 and 100 nM). Both ETs caused a dose-dependent increase in portal venous tension; the maximal tension (Tmax) was measured at 50 nM. The measured Tmax was higher for cirrhotic (ET-1: Tmax = 189%; ET-3: Tmax = 175%) than for normal rats (ET-1: Tmax = 130%; ET-3: Tmax = 151%). ET-3 produced a higher tension of portal veins in normal rats than ET-1. In conclusion, this study shows that portal veins from cirrhotic rats react more sensitively to ET than those from normal rats. Besides the ET-induced contraction of hepatic stellate cells, contraction of the portal vein and its intrahepatic branches, especially in cirrhotic individuals, has to be considered as a further mechanism of ET contributing to portal hypertension.

Correlation of endothelial vimentin content with hemodynamic parameters.

In mammalian species, vimentin is the sole intermediate filament protein of endothelial cells lining the chambers of the heart and the inner surface of large blood vessels. Obvious quantitative differences in the vimentin-like immunoreactivity of endothelial cells observed in different vascular segments led us to undertake a systematic survey on the endothelial content of vimentin throughout the heart chambers, the vena cava, the pulmonary trunk, and the aorta of the pig. Immunostaining and immunoblotting showed that vimentin in endothelial cells of cardiovascular segments exposed to high shear stress and blood pressure (pulmonary trunk, aorta, left ventricle) is approximately 2- to -3-fold higher than in endothelial cells exposed to lower levels of hemodynamic stress (vena cava, left and right atria, right ventricle). Throughout the aorta, an approximately 1.5-fold increase in the vimentin contents was observed in a proximal to distal direction. The total endothelial amount of vimentin was determined to be 1.2% (inferior vena cava) and 2-3.5% (aorta) of total cellular protein. These data support the notion that the endothelial vimentin cytoskeleton can adapt to different hemodynamic loads, indicating that vimentin might help endothelial cells to withstand the mechanical forces exerted by blood flow and blood pressure.