Die Gefäßverletzung – eine unterschätzte Entität?

Hintergrund

In der Traumatologie sind Gefäße eher selten betroffen und isolierte vaskuläre Traumata (VT) sind rar. Es existieren daher wenig belastbare und aktuelle Zahlen zu Inzidenz und Mortalität.

Fragestellung

Es wird anhand ausgewählter Referenzen sowie eigener abgeschlossener und laufender Studien aus Registerdaten des TraumaRegister DGU® (TR-DGU) zum VT im Rahmen der Schwerverletztenversorgung in Deutschland berichtet.

Material und Methode

Pointierte Literaturübersicht und Bericht über 2 retrospektive Auswertungen von Datensätzen des TraumaRegister DGU® (TR-DGU): Daten mit moderatem bis schwerem VT im Verletzungsmuster werden mit Daten ohne VT (non-VT) bei gleicher Verletzungsschwere verglichen. Zielgrößen sind Morbidität, Mortalität sowie Verlaufs- und Prognoseparameter.

Ergebnisse

In der Auswertung 2002–2012 (TR-DGU Projekt-ID 2013-011) zeichnete sich der Einfluss von Allokation und Versorgungsstufe der Traumazentren auf erwartete (EM) und beobachtete Mortalität (OM) von 2961 Fällen mit VT unter 42.326 Schwerverletzten (7 %) ab: Die Differenz von OM zu EM bei VT beträgt + 3,4 % vs. ± 0,1 % bei non-VT. Aufgrund der OM bei schwerem VT von 33,8 % vs. 16,4 % bei non-VT mit gleicher Verletzungsschwere wurde 2018 eine Folgeauswertung veranlasst (2008–2017; TR-DGU Projekt-ID 2018-045). Hier kann die Substratifizierung von isoliertem, führendem und begleitendem VT in der Versorgungsrealität signifikante Effekte von Versorgungsstufe, Allokation und Transport auf die OM zeigen. Nur bei VT zeigt sich eine relevante Nichtübereinstimmung von OM zu EM. Im Mittel etwa + 2 % und in Hochrisikokonstellationen mit VT bis zu + 29 % als Maß für die Relevanz von VT in der Traumaversorgung.

Schlussfolgerungen

Diese Ergebnisse legen eine weitere Optimierung der Schwerverletztenversorgung bei VT nahe, da sich VT-Vigilanz, Allokation, Transport und eine niedrigschwellige Frühverlegung als Ansatzpunkte ableiten lassen.

A Single-Center Experience With Total Percutaneous Implantation of a Low-Profile Thoracic Aortic Stent-Graft

PURPOSE

To evaluate the safety and effectiveness of total percutaneous implantation of the Zenith Alpha Thoracic (ZTA) endograft in the treatment of diseases of the descending thoracic aorta.

MATERIALS AND METHODS

A retrospective cohort study of 56 consecutive patients undergoing total percutaneous ZTA implantation between 2018 and 2020 was performed in a single center. Patients' demographics, clinical characteristics, anatomical parameters, operative details, device features, and postoperative outcomes were assessed. The primary endpoint was ongoing clinical success. A Cox regression model was used to determine the predictive factors of worse postoperative outcomes.

RESULTS

Eighty-three ZTA endografts were implanted in 35 men and 21 women with a mean age of 69±11 years for the treatment of 26 degenerative aneurysms, 15 type B dissections, and 8 penetrating ulcers, among others. Primary technical success was 100%, with a 30-day ongoing clinical success rate of 94.6%. The 1-year ongoing clinical success rate was 91.1% (51 patients), and freedoms from all-cause mortality, type 1 and 3 endoleaks, and any unplanned reintervention were, respectively, 95.3%, 91.4%, and 88.2% at 1 year. During follow-up, there was one case of surgical conversion for an aorto-esophageal fistula. On the contrary, neither aneurysmal rupture nor significant aneurysmal expansion was recorded. Repair of ruptured thoracic aorta and a high ratio of sheath outer diameter to external iliac artery diameter were found to be independently associated with worse outcomes, with adjusted odds ratios of 4.4 [1.5-15.3] and 4.9 [1.1-23.9], respectively.

CONCLUSION

The outcomes of total percutaneous implantation of ZTA endograft show excellent primary technical success and favorable midterm ongoing clinical success. Factors associated with worse outcomes include the repair of ruptured aorta and a high sheath to access vessel ratio.

MicroRNA-21 Controls Circadian Regulation of Apoptosis in Atherosclerotic Lesions

Background: The necrotic core partly formed by ineffective efferocytosis increases the risk of an atherosclerotic plaque rupture. microRNAs contribute to necrotic core formation by regulating efferocytosis and macrophage apoptosis. Atherosclerotic plaque rupture occurs at increased frequency in the early morning, indicating diurnal changes in plaque vulnerability. Although circadian rhythms play a role in atherosclerosis, the molecular clock output pathways that control plaque composition and rupture susceptibility are unclear. Methods: Circadian gene expression, necrotic core size, and apoptosis and efferocytosis in aortic lesions were investigated at different times of the day in Apoe^-/-Mir21^+/+ mice and Apoe^-/- Mir21^-/- mice after consumption of a high-fat diet for 12 weeks feeding. Genome-wide gene expression and lesion formation were analyzed in bone marrow (BM)-transplanted mice. Diurnal changes in apoptosis and clock gene expression were determined in human atherosclerotic lesions. Results: The expression of molecular clock genes, lesional apoptosis, and necrotic core size were diurnally regulated in Apoe^-/- mice. Efferocytosis did not match the diurnal increase in apoptosis at the beginning of the active phase. However, in parallel with apoptosis, expression levels of oscillating Mir21 strands decreased in the mouse atherosclerotic aorta. Mir21 knockout abolished circadian regulation of apoptosis and reduced necrotic core size, but did not affect core clock gene expression. Further, Mir21 knockout upregulated expression of pro-apoptotic XIAP associated factor 1 (Xaf1) in the atherosclerotic aorta, which abolished circadian expression of Xaf1. The anti-apoptotic effect of Mir21 was mediated by non-canonical targeting of Xaf1 through both Mir21 strands. Mir21 knockout in BM cells also reduced atherosclerosis and necrotic core size. Circadian regulation of clock gene expression was confirmed in human atherosclerotic lesions. Apoptosis oscillated diurnally in phase with XAF1 expression, demonstrating an early morning peak anti-phase to that of the Mir21 strands. Conclusions: Our findings suggest that the molecular clock in atherosclerotic lesions induces a diurnal rhythm of apoptosis regulated by circadian Mir21 expression in macrophages that is not matched by efferocytosis, thus increasing the size of the necrotic core.

Technical Aspects of Fenestrated Arch TEVAR With Preloaded Fenestration

Fenestrated thoracic endovascular aortic repair (f-TEVAR) has expanded the possibilities of endovascular arch repair, allowing treatment of pathologies involving the aortic arch that require sealing in Ishimaru zones 1 and 2. The growing number of implantations has increased physician experience and helped identify critical procedural points, mainly wire entanglement and device malrotation. Herein we describe a step-by-step approach to a f-TEVAR procedure with the Zenith fenestrated preloaded thoracic endograft, identifying potential pitfalls and suggesting problem-solving solutions.

Technical Aspects of Fenestrated Arch TEVAR With Preloaded Fenestration

Fenestrated thoracic endovascular aortic repair (f-TEVAR) has expanded the possibilities of endovascular arch repair, allowing treatment of pathologies involving the aortic arch that require sealing in Ishimaru zones 1 and 2. The growing number of implantations has increased physician experience and helped identify critical procedural points, mainly wire entanglement and device malrotation. Herein we describe a step-by-step approach to a f-TEVAR procedure with the Zenith fenestrated preloaded thoracic endograft, identifying potential pitfalls and suggesting problem-solving solutions.

Passing a Mechanical Aortic Valve With a Short Tip Dilator to Facilitate Aortic Arch Endovascular Branched Repair

PURPOSE

To present a novel technique to successfully cross a mechanical aortic valve prosthesis.

TECHNIQUE

A 55-year-old female patient with genetically verified Marfan syndrome presented with a 5-cm anastomotic aneurysm of the proximal aortic arch after previous ascending aortic replacement due to a type A aortic dissection in 2007. The patient also underwent mechanical aortic valve replacement in 1991. A 3-stage hybrid repair was planned. The first 2 steps included debranching of the supra-aortic vessels. In the third procedure, a custom-made double branched endovascular stent-graft with a short 35-mm introducer tip was implanted. The mechanical valve was passed with the tip of the dilator on the lateral site of the leaflet, without destructing the valve and with only mild symptoms of aortic insufficiency, as one leaflet continued to work. This allowed the implantation of the stent-graft directly distally of the coronary arteries. Postoperative computed tomography angiography showed no endoleaks and patent coronary and supra-aortic vessels.

CONCLUSION

Passing a mechanical aortic valve prosthesis at the proper position is feasible and allows adequate endovascular treatment in complex arch anatomy. However, caution should be taken during positioning of the endovascular graft as the tip may potentially damage the valve prosthesis.

Blunt traumatic thoracic aortic injuries: a retrospective cohort analysis of 2 decades of experience

OBJECTIVES

The aim of this study was to analyse and report the changes in the management of blunt traumatic aortic injuries (BTAIs) in a single centre during the last 2 decades.

METHODS

A retrospective analysis of all patients diagnosed with BTAI from January 1999 to January 2020 was performed. Data were collected from electronic/digitalized medical history records.

RESULTS

Forty-six patients were included [median age 42.4 years (16-84 years), 71.7% males]. The predominant cause of BTAI was car accidents (54.5%, n = 24) and all patients presented with concomitant injuries (93% bone fractures, 77.8% abdominal and 62.2% pelvic injuries). Over 70% presented grade III or IV BTAI. Urgent repair was performed in 73.8% of patients (n = 31), with a median of 2.75 h between admission and repair. Thoracic endovascular repair (TEVAR) was performed in 87% (n = 49), open surgery (OS) in 10.9% (n = 5) and conservative management in 2.1% (n = 1). Technical success was 82.6% (92.1% TEVAR, 79% OS). In-hospital mortality was 19.5% (17.5% TEVAR, 40% OS). Of these, 3 died from aortic-related causes. Seven (15.2%) required an early vascular reintervention. The median follow-up was 34 months (1-220 months), with 19% of early survivors having a follow-up of >10 years. Only 1 vascular reintervention was necessary during follow-up: secondary TEVAR due to acute graft thrombosis. Of the patients who survived the initial event, 6.7% died during follow-up, none from aortic-related causes.

CONCLUSIONS

Even with all the described shortcomings, in our experience TEVAR for BTAI proved to be feasible and effective, with few complications and stable aortic reconstruction at mid-term follow-up. With the current technical expertise and wide availability of a variety of devices, it should be pursued as a first-line therapy in these challenging scenarios.

Balloon-Assisted True Lumen Expansion and Fenestration of a Symptomatic, Triple-Barrel, Postdissection Thoracoabdominal Aneurysm with Collapsed True Lumen to Facilitate Endovascular Treatment with a t-Branch

BACKGROUND

To present the challenging endovascular treatment of a symptomatic triple-barrel (3 lumens; 1 true and 2 false lumens) aortic dissection case.

METHODS

A 43-year-old male was introduced with a symptomatic, 9 cm postchronic dissection thoracoabdominal aortic aneurysm with accompanying triple-barrel formation and true lumen collapse at the height of the distal thoracic aorta. The celiac axis and right renal artery were perfused from the true lumen, the left renal artery from the false lumen and the superior mesenteric artery from both lumens. Endovascular approach was decided due to the patient co-morbidities. Because of the collapsed true lumen, the aorta had to be preconditioned in order to facilitate the endovascular repair with a multibranched thoracoabdominal stent-graft. This was achieved through the dilation of the aortic true lumen with a 32 mm Coda balloon (COOK Medical, Bloomington, IN), then puncturing of the intimal flap in several places to create re-entries that were also dilated (first with a 12-mm noncompliant balloon and then with a compliant 32 mm Coda balloon), creating a single aortic lumen that could facilitate an endovascular repair with thoracic stent-grafts and an off-the-shelf multibranched endograft (t-Branch; COOK Medical). The patient was promptly discharged, and the 3-month follow-up CT-angiogram showed a satisfactory result with patent target vessels and only a small Type-IIb endoleak.

CONCLUSIONS

Preconditioning of the aorta using this technique is a feasible and safe approach for the treatment of complex thoracoabdominal postdissection aortic aneurysms presenting with a true lumen collapse.

Emergent Triple-Branched TEVAR and Redistribution of the Branches to the Supra-Aortic Target Vessels for Treatment of a Contained Ruptured Descending Aortic Aneurysm Associated With a Chronic Type A Aortic Dissection

PURPOSE

To demonstrate the feasibility of urgent endovascular treatment of a chronic type A dissection and contained rupture of the false lumen using a noncustomized triple-branched arch endograft, which necessitated reassignment of the branches to the supra-aortic vessels.

CASE REPORT:

A 57-year-old patient with a contained rupture of the descending thoracic aorta, in the setting of a chronic type A dissection and a maximum aortic diameter of 85 mm, was converted to endovascular repair after failure of an open surgical approach. A custom-made triple-branched arch endograft designed for another patient was employed, with concomitant occlusion of the false lumen using a Candy Plug occluder. To adjust the graft's configuration to the patient's anatomy, the supra-aortic vessels were not assigned to the originally planned branches. The 12-month follow-up angiography demonstrated a satisfactory result.

CONCLUSION

A noncustomized triple-branched arch endograft can be used in an emergency setting to treat chronic type A dissection, reassigning the branches to the supra-aortic vessels as needed.

The Munich Valsalva Implantation Technique (MuVIT) for Cardiac Output Reduction During TEVAR: Vena Cava Occlusion With the Valsalva Maneuver

PURPOSE

To demonstrate a physiologically induced alternative to the typical methods of reducing cardiac output during deployment of stent-grafts in the aortic arch and proximal aorta.

TECHNIQUE

A modified Valsalva maneuver, the Munich Valsalva implantation technique (MuVIT), to raise the intrathoracic pressure, minimize backflow, and reduce the cardiac output is illustrated in a patient undergoing a triple-branch thoracic endovascular aortic repair (TEVAR). During manual mechanical ventilation, the adjustable pressure-limiting valve is carefully closed to 25 mm Hg, creating "manual bloating" of the lungs and sustained apnea. The increased intrathoracic pressure causes compression of the vena cava and pulmonary veins, reducing the venous backflow and gradually decreasing the arterial pressure. Once the desired pressure is obtained, the stent-graft is accurately deployed. The airway pressure is thereupon slowly reduced, and the patient is taken back to normal ventilation. The procedure is then finished following standard practice.

CONCLUSION

The MuVIT is a simple, noninvasive technique for cardiac output reduction during aortic arch TEVAR, eliminating the need for other invasive techniques.

[Aortic Aneurysm: Fenestrated/Branched Endovascular Aortic Repair (EVAR) and Fenestrated/Branched Thoracic Endovascular Aortic Repair (TEVAR). Is Total Endovascular Repair Already Here?]

Five years after the first endovascular aortic repair (EVAR), Park et al. reported the first implantation of a fenestrated endoprosthesis. In the meantime, advanced generations of new fenestrated and branched endografts evolved. Endografts for complex pathologies are either so-called "off-the-shelf" grafts with predetermined length, width, diameter and clock position of the branches and fenestrations, predetermined by the manufacturer, "custom-made" grafts which need to be sized and planned individually for patients with specific thoracoabdominal anatomy. Open aortic repair in the treatment of thoracoabdominal aortic aneurysm (TAAA) still remains challenging and is associated with high morbidity and mortality, even in the elective setting. The ongoing development of endovascular treatment modalities, such as fenestrated and branched endovascular aneurysm repair (F-EVAR, B-EVAR), enables less invasive procedures for more challenging aortic pathologies. In recent years, extensive endovascular treatment of the aortic arch to the thoracoabdominal segment has become more and more important, but its outcomes have not been completely evaluated. The aim of this is article is to provide an overview of the currently available endovascular treatment options for complex aortic aneurysms requiring extensive coverage from the aortic arch to the infrarenal aorta.

[Thoracic Aortic Aneurysms - Diagnosis and Treatment Strategies]

Thoracic aortic aneurysms are a relatively uncommon disease, with an incidence of 10.4/100 000, with an increase in the last decades, due to the increased quality of vascular screening. Several imaging techniques like thoracic radiography, echocardiography, magnetic resonance (MRI) or positron emission tomography (PET) can be used for the diagnosis of such condition, whose first diagnosis is usually incidental. The gold standard for aneurysm evaluation is computed tomography angiography (CTA), which allows precise diameter assessment and accurate preoperative planning. Advancements in imaging techniques, through electrocardiography (ECG)-gated CTA, permit to avoid movement artifacts and have a more precise definition of proximal aortic segments (aortic arch, ascending aorta).The urgent or emergent treatment of thoracic aneurysms is indicated in symptomatic patients and in case of rupture, respectively. The current European Society for Vascular Surgery guidelines recommend the elective treatment of thoracic aneurysms with a diameter > 55 mm, since diameters of 55 - 60 mm are associated with a rupture risk of 10 %/year. Lower perioperative morbidity and mortality rates have been demonstrated for endovascular repair in comparison with open surgery. According to the current guidelines, the treatment of choice is endovascular, through the implantation of an aortic stent graft (thoracic endovascular aortic repair, TEVAR), while open surgery is reserved to young patients, fit for open surgery. Hybrid procedures, introduced in 2000, include the debranching of supra aortic vessels and TEVAR and are a well established procedure for the treatment of aneurysms involving the aortic arch. The increasing research and expertise in endovascular surgery lead to the development of complex procedures, like chimney TEVAR, fenestrated and branched TEVAR which allowed to reach proximal landing zone to the ascending aorta.

Current evidence on aortic remodeling after endovascular repair

Anatomical changes after endovascular repair (EVAR) of abdominal aortic aneurysms (AAAs) are thoroughly studied as they could affect the long-term postoperative outcome. The aim of the present study was to review the literature and summarize the recent data regarding the aortic remodeling and its clinical significance. A continuous aortic neck expansion is observed after EVAR and is more rapid at the first month and during the third postoperative year. This aortic neck dilation is not influenced by the type of proximal stent-graft fixation, is comparable to open surgical aneurysm repair and is most probably related with the natural progression of aneurismal disease. Aortic neck angulation reduces significantly immediately after EVAR and then continues to reduce slowly and gradually. Neck angulations ≥60° have a greater reduction compared to neck angulations <60°. An expansion of the common iliac arteries at the distal landing zone is also observed after EVAR and is more prominent in the first six postoperative months. A postoperative increase of the distance between superior mesenteric artery and iliac bifurcations (aortoiliac elongation) is described and is associated with increased type I endoleaks and reinterventions. The aneurysm sac diameter most frequently reduces after EVAR in absence of an endoleak and this aneurysm sac regression has been associated with the stent-graft type.

[Relevance of Vascular Trauma in Trauma Care - Impact on Clinical Course and Mortality]

There is a lack of evidence as to the relevance of vascular trauma (VT) in patients with severe injuries. Therefore, we reviewed registry data in the present study in order to systematically objectify the effect of VT in these patients. This study aimed to provide an adequate picture of the relevance of vascular trauma and to identify adverse prognostic factors. In a retrospective analysis of records from the TraumaRegister DGU® (TR-DGU) in two subgroups with moderate and severe VT, we examined the records for differences in terms of morbidity, mortality, follow-up and prognostic parameters compared to patients without VT with the same ISS. From a total of 42,326 patients, 2,961 (7 %) had a VT, and in 2,437 cases a severe VT (AIS ≥ 3) was diagnosed (5.8 %). In addition to a higher incidence of shock and a 2 to 3-fold increase in fluid replacement and erythrocyte transfusion, patients with severe VT had a 60 % higher rate of multiple organ failure, and in-hospital mortality was twice as high (33.8 %). The massively increased early mortality (8.0 vs. 25.2 %) clearly illustrates how severely injured patients are placed at risk by the presence of a relevant VT with a comparable ISS. In our opinion, due to an unexpected poor prognosis in the TR-DGU data for vascular injuries, increased attention is required in the care of severely injured patients. Based on our comprehensive analysis of negative prognostic factors, a further adjustment to the standards of vascular medicine could be advisable. The influence of the level of care provided by the admitting hospital and the relevance of a further hospital transfer to prognosis and clinical outcome is currently being analysed.

Vascular compression syndromes

Dealing with vascular compression syndromes is one of the most challenging tasks in Vascular Medicine practice. This heterogeneous group of disorders is characterised by external compression of primarily healthy arteries and/or veins as well as accompanying nerval structures, carrying the risk of subsequent structural vessel wall and nerve damage. Vascular compression syndromes may severely impair health-related quality of life in affected individuals who are typically young and otherwise healthy. The diagnostic approach has not been standardised for any of the vascular compression syndromes. Moreover, some degree of positional external compression of blood vessels such as the subclavian and popliteal vessels or the celiac trunk can be found in a significant proportion of healthy individuals. This implies important difficulties in differentiating physiological from pathological findings of clinical examination and diagnostic imaging with provocative manoeuvres. The level of evidence on which treatment decisions regarding surgical decompression with or without revascularisation can be relied on is generally poor, mostly coming from retrospective single centre studies. Proper patient selection is critical in order to avoid overtreatment in patients without a clear association between vascular compression and clinical symptoms. With a focus on the thoracic outlet-syndrome, the median arcuate ligament syndrome and the popliteal entrapment syndrome, the present article gives a selective literature review on compression syndromes from an interdisciplinary vascular point of view.

Do contrast media (iomeprol, gadopentetate dimeglumine) deteriorate ischemia/reperfusion injury of the liver?

BACKGROUND

Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. One of the important diagnostic procedures to recognize reperfusion failure is contrast-enhanced computed tomography or magnetic resonance imaging.

PURPOSE

To examine the additional effect of contrast media (iomeprol and gadopentetate dimeglumine) on hepatic microcirculation and hepatic cellular damage in the phase of early ischemia/reperfusion injury of the rat liver.

MATERIAL AND METHODS

The partial warm ischemia-reperfusion injury model of rat liver was used. Microcirculation and leukocyte-endothelium interaction were measured by intravital microscopy. Hepatic cellular damage was indicated by liver enzyme activity in the sera. The evaluation parameters were measured at baseline and at 30, 60, and 90 min after reperfusion. The contrast media (iomeprol group, n = 6; gadopentetate dimeglumine group, n = 6) or Ringer's solution (control group, n = 8) were applied after 30 min of reperfusion.

RESULTS

No additional injury to the ischemia/reperfusion injury of the liver after intravenous application of radiographic contrast media was found. Some protective effect was even recorded after application of iodinated contrast media.

CONCLUSION

The use of contrast media during diagnostic procedure of the liver seems to be relatively safe, even in the stage of early reperfusion after liver transplantation.

Dynamic changes of post-ischemic hepatic microcirculation improved by a pre-treatment of phosphodiesterase-3 inhibitor, milrinone

BACKGROUND

Phosphodiesterase-3 inhibition has been shown to attenuate hepatic warm ischemia-reperfusion injury. The aim of this study was to investigate the effect of milrinone, phosphodiesterase-3 inhibitor, on post-ischemic microcirculation of rat livers by intravital microscopy.

MATERIALS AND METHODS

Male Wistar rats were randomly assigned to three groups; group A, milrinone pre-treatment; group B, ischemic pre-conditioning; and group C, no pre-treatment. All animals underwent a 60-min warm ischemia of the left lateral liver lobe. Microvascular perfusion and leukocyte-endothelial interaction were observed by intravital videomicroscopy. Hepatocellular viability and cellular damage were quantified by adenosine triphosphate tissue concentration as well as alanine aminotransferase and lactate dehydrogenase blood levels, respectively.

RESULTS

In groups A and B, cyclic AMP hepatic tissue concentration was elevated significantly. After reperfusion, microvascular perfusion in hepatic sinusoids was significantly better maintained, and the number of adherent leukocytes was reduced in sinusoids and in post-sinusoidal venules in these rats. Serum transaminase blood levels were suppressed significantly in these groups compared with controls.

CONCLUSION

The demonstrated improvement of hepatic microcirculation is certainly derived from milrinone induced cell protection in ischemia reperfusion of the liver. This effect is outlined by improved energy status and reduced liver enzyme liberation and mimics the effect of ischemic pre-conditioning.

Development and functional consequences of LPS tolerance in sinusoidal endothelial cells of the liver

Kupffer cells and liver sinusoidal endothelial cells (LSEC) clear portal venous blood from gut-derived bacterial degradation products such as lipopolysaccharide (LPS) without inducing a local inflammatory reaction. LPS tolerance was reported for Kupffer cells, but little is known whether sensitivity of LSEC toward LPS is dynamically regulated. Here, we demonstrate that LSEC react to LPS directly as a function of constitutive Toll-like receptor 4 (TLR4)/CD14 expression but gain a LPS-refractory state upon repetitive stimulation without loss of scavenger activity. LPS tolerance in LSEC is characterized by reduced nuclear localization of nuclear factor-kappaB upon LPS rechallenge. In contrast to monocytes, however, TLR4 surface expression of LSEC is not altered by LPS stimulation and thus does not account for LPS tolerance. Mechanistically, LPS tolerance in LSEC is linked to prostanoid production and may account for cross-tolerance of LPS-treated LSEC to interferon-gamma stimulation. Functionally, LPS tolerance in LSEC results in reduced leukocyte adhesion following LPS rechallenge as a consequence of decreased CD54 surface expression. Furthermore, LPS tolerance is operative in vivo, as we observed by intravital microscopy-reduced leukocyte adhesion to LSEC and improved sinusoidal microcirculation in the liver after repetitive LPS challenges. Our results support the notion that LPS tolerance in organ-resident scavenger LSEC contributes to local hepatic control of inflammation.

Oxygen radicals promote ICAM-1 expression and microcirculatory disturbances in experimental acute pancreatitis

BACKGROUND/AIMS

The course of pancreatitis is paralleled by a drastic reduction in organ perfusion and increased ICAM-1-mediated leukocyte-endothelial interaction. We aimed to evaluate the effect of oxygen radicals on ICAM-1 expression and the microcirculation in severe acute pancreatitis using the oxygen radical scavenger dimethylsulfoxide (DMSO).

MATERIALS AND METHODS

Severe pancreatitis was induced in rats (n = 32) who were randomly assigned to one of two groups: either 4 ml/kg 50% DMSO/saline (v/v) started 3 h after induction of pancreatitis or 4 ml/kg saline (control). Microcirculation was evaluated by intermittent intravital microscopy. Serum amylase and lipase, histomorphometric changes, immunohistochemistry for ICAM-1 expression and 24-hour survival were investigated.

RESULTS

Leukocyte adherence was significantly reduced (4.4 +/- 0.47 vs. 5.58 +/- 0.69 sticker/100 micro m, p < 0.05), and mean capillary (0.96 +/- 0.06 vs. 0.45 +/- 0.13 mm/s; p < 0.01) and venous erythrocyte velocity (1.16 +/- 0.12 vs. 0.58 +/- 0.16 mm/s, p < 0.01) were significantly increased by DMSO treatment. Microcirculatory disturbances were paralleled by an increase in endothelial ICAM-1 expression, whereas DMSO reduced ICAM-1 expression.

CONCLUSION

DMSO improves pancreatic microcirculation and reduces ICAM-1 expression and subsequent leukocyte adhesion, suggesting an important role of oxygen free radicals in the pathway of endothelial ICAM-1 expression and microcirculatory disturbances in acute pancreatitis.

Desmopressin impairs microcirculation in donor pancreas and early graft function after experimental pancreas transplantation

BACKGROUND

Protective effects of desmopressin in brain dead organ donors oppose reports on a hypercoagulatory potential and an increased leukocyte-endothelial interaction (LEI) after application of the drug. The aim was to evaluate the effect of desmopressin on organ donor's pancreas and early graft function.

METHODS

Donor microcirculation was evaluated via intra-vital microscopy (IVM) in 24 BR (di/di) rats with central diabetes insipidus, randomly assigned to groups I (control without desmopressin application), II (single i.v. application, no pretreatment) or group III (single i.v. desmopressin application, s.c. pretreatment for 3 days). Microcirculation in recipients was evaluated 1 hr and 6 hr after syngenic pancreas transplantation. Groups III and I served as organ donors. After IVM specimens were taken for histology and immunohistochemistry.

RESULTS

Desmopressin in II vs. I led to temporarily (30') increased LEI (Sticker 274.3+/-87.7 vs. 76.5+/-31.1/mm2 endothelial surface; P<0.01) and impaired microcirculation (MCEV 0.43+/-0.07 vs. 0.99+/-0.06 mm/s; P<0.01). Repeated application reduced MCEV and increased LEI for up to 12 hr. Histology in I vs. III showed increased inflammation (n.s.), necrosis (P<0.05) and vacuolization (P<0.01). Immunohistochemistry revealed increased endothelial P-selectin 20' after application. 6 hr after reperfusion organs from III showed reduced MCEV and increased LEI (P<0.01).

CONCLUSION

Repeated application of desmopressin impairs graft microcirculation. Perfusion of the pancreas is significantly reduced at the beginning of organ tissue conservation as well as after reperfusion. These disturbances might partly be due to observed endothelial P-selectin expression. Application of desmopressin up to 12 hr prior to organ explantation may impact graft quality.

Nonfreezing cryopreservation--a possible means of improving long-term transplant function?

Improving organ preservation techniques for transplantation is one of the most important goals of transplantation research. We have established a new, nonfreezing cryopreservation method to optimize the viability of rat kidneys for transplantation with up to 4 M dimethylsulphoxide (DMSO) in EuroCollins solution (EC) at -5 degrees C to -15 degrees C. We have confirmed the occurrence of a tubular and glomerular defect pattern that mediates acute tubular necrosis (ATN) and that may be a cause of major histocompatibility complex (MHC) independent immunological components of chronic transplant rejection. The extent of this defect [transplant survival and function, 31P-NMR spectroscopy, histological defect index] in the nonfreezing cryopreserved groups (n = 22) is significantly (P = 0.017) lower than in the simple cold storage group (n = 12). Quality and localization of the lesions in kidney transplants can elucidate the context of organ preservation, progressive hyperfiltration defects, and the occurrence of graft failure without elevated frequency of acute rejection episodes. These results indicate that further efforts to provide higher pretransplant organ viability without using it to prolong cold storage intervals may provide better insight into MHC-independent factors of chronic transplant failure and may result in improved long-term transplant outcome.

Surgical treatment of invasive penile cancer--the Heidelberg experience from 1968 to 1994

OBJECTIVES

This study was performed to establish oncological guidelines for the surgical treatment of invasive penile cancer.

MATERIALS AND METHODS

The medical records of 51 patients with invasive penile cancer seen between 1968 and 1994 were reviewed in respect to treatment and long-term outcome.

RESULTS

For stage T1 tumors treated with organ-preserving procedures the local recurrence rats was 56%, whereas no patient experienced a local recurrence after partial amputation. For stage T2 tumors, local recurrence rate was 100% (organ preservation) versus 20% (amputative procedures). There was no significant difference related to regional recurrence between surveillance, inguinal radiation and lymphadenectomy for stage N0 tumors. For N+ stages, survival was related to the extent of inguinal metastasis after dissection (5-year survival rate for N1: 71 vs. 33% for N2/3).

CONCLUSIONS

Organ-preserving procedures include a high risk of local and regional recurrence. Adjuvant regional lymphadenectomy seems beneficial only in patients with solitary metastasis.

[Effect of HLA compatibility on the transplanted kidney in relation to recipient age]

Donor-recipient histocompatibility, as evaluated by the HLA matching results, plays an important role in the outcome of renal transplants, although much controversy surrounds the benefit of kidney allocation based on HLA typing. In this report HLA matching and survival data on 1,342 transplants performed at the University of California at San Francisco between 1984 and 1992 and treated uniformly by quadruple immunosuppression were analyzed in relation to the recipient's age. With respect to the influence of the increasing number of mismatches from 0 to 6, the analysis revealed decreasing 3-year graft survival rates as follows: 85.4%; 87.3%; 71.3%; 78.2%; 75.8%; 70.9% and 67.5%. Whereas the impact of cold ischemia time and histocompatibility was equally important during the 3-year postoperative period, the essential positive influence of good HLA matching on the long-term graft survival was demonstrated. The children aged between 5 and 18 years were identified as a high-risk group by the analysis, HLA-A incompatibility being attributed to poor graft survival in this age group. With respect to the effect of HLA-A histoincompatibility, the data provide evidence that HLA-A matching results seem to play an important role in graft survival in children, whereas transplants well matched in terms of HLA-B did well in adult recipients. No age difference in the impact of HLA-DR could be detected. In conclusion, HLA matching is still essential. It seems that there are differences in the impact of HLA loci in relation to the recipient's age.

[Improved organ survival in transplantation of pediatric kidneys by optimizing donor-recipient size relation]

The risk for renal allograft failure in pediatric renal transplantation (donor age below 3 years) is still high, although it has been reduced by the use of potent immunosuppressive therapies. In this study we report on experience with 80 kidneys of donors below 3 years of age (PD) transplanted at the University of California at San Francisco Hospital in accordance with the policy of minimizing donor-recipient size differences. The graft survival rates were comparable with the results for adult donors, 18-50 years of age (AD, n = 891): at 1 year PD 74.1% vs AD 85.5%, at 2 years PD 70.5% vs AD 80.2%, at 3 years PD 63.5% vs AD 76%; there were no significant differences. The policy of minimizing donor-recipient size differences seems to improve graft survival rates, avoiding the tendency for hyperfiltration phenomena and possibly being responsible for this salutary effect. We conclude that the use of pediatric donor kidneys can yield excellent long-term results independent of primary disease if the donor-recipient size difference is minimized and a potent immunosuppressive regimen is employed.