Prognostic benefits of early vascular surgical intervention in patients with major peripheral vascular complications following transcatheter aortic valve implantation

OBJECTIVES

This study aimed to analyze the incidence, surgical management of major vascular complications, and outcomes in patients undergoing transfemoral (TF) transcatheter aortic valve replacement (TAVR) at our center after strict selection of the access route, carefully considering all known major predictors.

METHODS

Data of 494 consecutive patients with pre-interventional multi-slice computed tomography (CT) of the aorta who had undergone TF TAVR from 2009 to 2019 were analyzed.

RESULTS

In total, 23/494 (4.7%) patients had major vascular and access-related complications of peripheral vessels and/or infrarenal aorta. These included hematomas that met the Valve Academic Research Consortium 3-criteria of major vascular complications (7/494, 1.4%), arterial dissections (3/494, 0.6%), pseudoaneurysm (6/494, 1.2%), thrombus of the external iliac artery leading to acute limb ischemia (1/494, 0.2%), fistula (1/494, 0.2%), and perforation (5/494, 1.0%). In total, 17/23 (73.9%) major vascular complications required immediate endovascular and/or open surgery. In 16/17 (94%) cases, only 1 surgical procedure was performed. The long-term survival of patients with and without major vascular complications of the peripheral vessels was determined after 2 years.

CONCLUSIONS

Early vascular surgery intervention reversed the mortality disadvantage in patients with major complications of the peripheral vessels after TAVR. This underscores the importance of immediate vascular surgery stand-by as an indispensable requirement.

Reversible biliary occlusion in a small animal model: first description of a new technique

Background

Experimental models with reversible biliary occlusion resulted in a high mortality of the animals, up to 20–60% according to the literature. Our aim was to assess a safe and valid technique for reversible biliary occlusion with a low mortality.

Methods

We randomized 30 rats into two groups: with bile duct occlusion (BDO, n=18) and with sham manipulation of the extrahepatic bile duct (control, n=12). We used a removable vascular clip for temporary occlusion of the extrahepatic bile duct. The clip was removed on postoperative day (POD) 2. On POD 2, 3, and 5, we measured the hepatocellular injury and metabolic function markers in serum. Activation of mononuclear cells (HIS36) and expression of regeneration markers [cytokeratin 19, hepatic growth factor (HGF)-α, and HGF-β] were determined by immunohistochemistry.

Results

The survival rate was 96.67% (1/30); one animal died. The mortality in the BDO group was 6% (1/18) and that in the control group was 0% (0/12). BDO resulted in a sharp increase of hepatocellular injury and cholestatic parameters on POD 2 with a rapid decline till POD 3. Significantly strongest activation of Kupffer cells and expression of proliferation markers were found until POD 5 after BDO.

Conclusion

The clip technique is a safe, cheap, and valid method for reversible biliary occlusion with an extremely low mortality.

[Routine subclavian revascularisation employing regional anaesthesia]

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.

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.

Risk of gas embolism in hand-assisted versus total laparoscopic hepatic resection

Laparoscopic hepatic resection represents an alternative to open surgery in patients with advanced underlying hepatic disease. Management of haemorrhage and the risk of gas embolism are the major problems in laparoscopic liver surgery. In this study, safety and efficacy of liver dissection using ultrasonic energy was investigated in hand-assisted versus total laparoscopic surgery. The study had a special emphasis on evaluating the risk of gas embolism during both procedures. Female pigs were divided into two groups for A) total laparoscopic (n=7), and B) hand-assisted laparoscopic (n=7) hepatic resection. For tissue dissection, an ultrasound aspirator (CUSA) was used in both groups. Laparoscopic procedure was performed under a CO2 pneumoperitoneum (intraperitoneal pressure: 12 mmHg). Before dissection, a Pringle manoeuver was carried out. The anaesthetized pigs were monitored haemodynamically by an arterial line and Swan-Ganz catheter. Transoesophageal echocardiography (TEE) was performed with special attention to the right atrium and ventricle. Gas emboli were graded according to size and correlated with haemodynamic and blood-gas data. In both groups, the ultrasound-aspirator enabled an effective tissue dissection. In total laparoscopic hepatic resection, TEE monitoring disclosed gas embolism in 5/7 (71%) animals. In 3/7 (42%) animals, gas embolism was accompanied by a sequence of cardiac arrhythmia. No direct correlation was noted between episodes of embolism and blood-gas variables. None of the pigs died after episodes of embolization. In hand-assisted liver resection, no air embolism was noted. The internal hand impressively facilitated organ exposure and provided an immediate and efficient haemorrhage control. The use of an ultrasound aspirator system enables an effective laparoscopic hepatic dissection. Total laparoscopic liver dissection is at increased risk for gas embolism, whereas hand-assisted laparoscopic procedure appears to reduce this risk. Due to tactile response and facilitated retraction of the liver parenchyma, the hand-assisted procedure shows impressive advantages in laparoscopic liver surgery.

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.

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 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.

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]

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.

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.

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.

[Changes in portal blood flow volume by CO2 pneumoperitoneum in the rat]

To measure alterations of hemodynamics in the portal vein during increasing intraabdominal pressure due to carbon dioxide insufflation an established animal model of laparoscopic surgery in the rat was extended by implantation of a perivascular flow probe. Using this technique an adequate flowmetry of the portal vein was achievable in all animals. The installation of a CO2 pneumoperitoneum with elevating intraabdominal pressure led to a linear decrease of portal venous flow. This might compromise liver function and cell-conveyed immunoresponse in the liver during laparoscopic surgery.

[Intraoperative autotransfusion and use of cell saver systems]

In the last two years we have performed intraoperative autotransfusion by a cell-saving-system in 46 patients causing a 70%-reduction in the need of homologous blood transfusion. 20% of these patients did not need homologous blood at all. Besides minimizing transfusion-associated risks, intraoperative autotransfusion had an evident cost-sparing effect.