P. Lamby

A prospective randomised, open-labeled, trial comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing liver transplantation for hepatocellular carcinoma

BackgroundThe potential anti-cancer effects of mammalian target of rapamycin (mTOR) inhibitors are being intensively studied. To date, however, few randomised clinical trials (RCT) have been performed to demonstrate anti-neoplastic effects in the pure oncology setting, and at present, no oncology endpoint-directed RCT has been reported in the high-malignancy risk population of immunosuppressed transplant recipients. Interestingly, since mTOR inhibitors have both immunosuppressive and anti-cancer effects, they have the potential to simultaneously protect against immunologic graft loss and tumour development. Therefore, we designed a prospective RCT to determine if the mTOR inhibitor sirolimus can improve hepatocellular carcinoma (HCC)-free patient survival in liver transplant (LT) recipients with a pre-transplant diagnosis of HCC.Methods/DesignThe study is an open-labelled, randomised, RCT comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing LT for HCC. Patients with a histologically confirmed HCC diagnosis are randomised into 2 groups within 4-6 weeks after LT; one arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol and the second arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol for the first 4-6 weeks, at which time sirolimus is initiated. A 21/2 -year recruitment phase is planned with a 5-year follow-up, testing HCC-free survival as the primary endpoint. Our hypothesis is that sirolimus use in the second arm of the study will improve HCC-free survival. The study is a non-commercial investigator-initiated trial (IIT) sponsored by the University Hospital Regensburg and is endorsed by the European Liver and Intestine Transplant Association; 13 countries within Europe, Canada and Australia are participating.DiscussionIf our hypothesis is correct that mTOR inhibition can reduce HCC tumour growth while simultaneously providing immunosuppression to protect the liver allograft from rejection, patients should experience less post-transplant problems with HCC recurrence, and therefore could expect a longer and better quality of life. A positive outcome will likely change the standard of posttransplant immunosuppressive care for LT patients with HCC.Trial RegisterTrial registered at http://www.clinicaltrials.gov: NCT00355862(EudraCT Number: 2005-005362-36)

Sirolimus Use in Liver Transplant Recipients With Hepatocellular Carcinoma: A Randomized, Multicenter, Open-Label Phase 3 Trial.

Background We investigated whether sirolimus-based immunosuppression improves outcomes in liver transplantation (LTx) candidates with hepatocellular carcinoma (HCC). Methods In a prospective-randomized open-label international trial, 525 LTx recipients with HCC initially receiving mammalian target of rapamycin inhibitor–free immunosuppression were randomized 4 to 6 weeks after transplantation into a group on mammalian target of rapamycin inhibitor–free immunosuppression (group A: 264 patients) or a group incorporating sirolimus (group B: 261). The primary endpoint was recurrence-free survival (RFS); intention-to-treat (ITT) analysis was conducted after 8 years. Overall survival (OS) was a secondary endpoint. Results Recurrence-free survival was 64.5% in group A and 70.2% in group B at study end, this difference was not significant (P = 0.28; hazard ratio [HR], 0.84; 95% confidence interval [95% CI], 0.62; 1.15). In a planned analysis of RFS rates at yearly intervals, group B showed better outcomes 3 years after transplantation (HR, 0.7; 95% CI, 0.48-1.00). Similarly, OS (P = 0.21; HR, 0.81; 95% CI, 0.58-1.13) was not statistically better in group B at study end, but yearly analyses showed improvement out to 5 years (HR, 0.7; 95% CI, 0.49-1.00). Interestingly, subgroup (Milan Criteria-based) analyses revealed that low-risk, rather than high-risk, patients benefited most from sirolimus; furthermore, younger recipients (age ⩽60) also benefited, as well sirolimus monotherapy patients. Serious adverse event numbers were alike in groups A (860) and B (874). Conclusions Sirolimus in LTx recipients with HCC does not improve long-term RFS beyond 5 years. However, a RFS and OS benefit is evident in the first 3 to 5 years, especially in low-risk patients. This trial provides the first high-level evidence base for selecting immunosuppression in LTx recipients with HCC.

Transcutaneous pO2 imaging during tourniquet-induced forearm ischemia using planar optical oxygen sensors.

Background: Oxygen‐dependent quenching of luminescence using transparent planar sensor foils was shown to overcome the limitations of the polarographic electrode technique in an animal model. This method was then transferred to a clinical setting to measure the transcutaneous pO2 (ptcO2).

Evaluation of the vascular integrity of free flaps based on microcirculation imaging techniques

BACKGROUND A free-flap graft refers to the free transfer of tissue to cover tissue defects caused by trauma or malperfusion in plastic surgery. The basic principle, which makes a free flap working is an adequate blood flow. We applied new techniques which are able to detect the blood flow of the anastomosis and of dermal and subdermal tissue layers in a reliable way. METHODS To this end we applied innovative Ultrasound-techniques (contrast enhanced high resolution Ultrasound (US), color coded Doppler sonography (CCDS), Cross Beamtrade mark, Power Doppler, Tissue Harmonic Imagingtrade mark (THI), Speckle Reduction Imagingtrade mark (SRI)), as well as the Indocyanine Green (ICG) fluorescence angiography to evaluate the vascular integrity of 15 parascapular flaps implanted to the fore foot over a period of four years. The age of the subjects ranged from 16 to 60 years. The US machine (GE Logiq 9) was equipped with a Logiq 9L transducer (6-9 MHz) and the modalities of CHI (Contrast Harmonic Imaging) and True Agent Detection (dual view of B-Mode and contrast mode). RESULTS The borders of the investigated flaps could be best detected using Cross Beamtrade mark Technology with SRItrade mark and THItrade mark. Power Doppler was able to detect anastomotic vessels even if they were twisted or elongated. Reduced perfusion curves were seen in cases with low anastomotic flow in CCDS. The CHItrade mark allowed dynamic flow detection of the microcirculation of the tissue graft over a depth of up to 3 cm including quantitative perfusion curves of tissue microcirculation by using TICtrade mark analysis. There is a strong correlation between the perfusion indices measured by ICG fluorescence angiography and CHItrade mark. Furthermore the ICG showed a remarkable enhancement of fluorescence in the flap borders, which need to be explored in future investigations. CONCLUSION These new applications provide useful and effective methods for improved postoperative monitoring of free flaps in plastic surgery and can lead to substantial reduction in the overall risk of flap failure.

Improvements in high resolution ultrasound for postoperative investigation of capillary microperfusion after free tissue transfer.

INTRODUCTION High resolution ultrasound (US) techniques as implemented in the latest generation of US machines provide imminently better resolution compared to previous high resolution models. This improvement is based on advanced transducer technologies as well as updated post-processing procedures. Furthermore, matrix linear transducers providing frequencies from 6 to 15 MHz are now available. The aim of the study was the evaluation of these new techniques for the immediate postoperative investigation of microcirculation after free tissue transfer by supplemental use of Contrast-Enhanced Ultrasound Imaging (CEUS). PATIENTS AND METHODS To this end, we investigated 12 patients who underwent free tissue transfer in order to cover tissue defects in various body regions. We utilized the new GE Logiq E9 equipped with a linear 6-9 MHz and a matrix 6-15 MHz probe as well as the GE Logiq 9 with the previous version of the linear 6-9 MHz probe. Both machines provide the modalities of SRI, Cross Beam and THI. The perfusion curves were quantitatively analyzed using digital cine sequences (Qontrast, Bracco, Italy). Furthermore, two independent investigators evaluated the digitally recorded images with respect to the resolution of details based on a scale ranging from 0 to 5, and after application of 2.4 ml SonoVue (Bracco, Italy), evaluated the image quality regarding the representation of tissue perfusion. RESULTS None of the free flaps showed clinical or laboratory signs of flap failure during the hospital stay. Several flaps showed typical perfusion patterns relating to the flap type. The combination of SRI, Cross Beam and THI allows, in most cases, a more exact differentiation of tissue graft outlines and tissue composition, in particular the tissue texture, compared to the use of B-scan only. In addition, the high resolution matrix technology combined with the broader spectrum of 6-15 MHz considerably improves the representation of image details compared to multifrequency probes with 6-9 MHz. The use of updated post-processing procedures as well as new transducer technologies in CEUS also results in improved resolution and thus achieves a higher score compared to previous models. CONCLUSION At present, these new US technologies combined with the updated 6-9 MHz probe provide the optimal assessment of perfusion in cutaneous, subcutaneous and deeper tissue layers. The additional use of new multifrequency 6-15 MHz matrix probes improves the resolution in the B-mode to an even higher degree.

Contrast enhanced ultrasound (CEUS) and time intensity curve (TIC) analysis in compartment syndrome: First results

OBJECTIVE Purpose of this study was to monitor changes of microcirculation in acute compartment syndrome using contrast enhanced ultrasound (CEUS) and to assess the modified perfusion with a special quantification software. METHODS 8 patients with trauma of the lower limb or the upper extremity were enrolled after acute compartment syndrome was diagnosed clinically and by intracompartmental pressure measurement. The qualitative analysis of the corresponding compartment was assessed using B-scan mode and CEUS simultaneously. CEUS was performed using a multifrequence probe (6-9 MHz, LOGIQ E9 GE) after a i.v. bolus injection of 2 × 2.4 ml contrast agent (SonoVue(®), Bracco, Italy). Digital raw data were stored as cine loops up to 2 minutes. Retrospectively semiquantitative perfusion analysis was performed using time intensity curve analysis and the quantification software QONTRAST(®). RESULTS 6 out of 8 patients had to be operated due to clinical symptoms and to a pressure perfusion gradient lower than 30 mm Hg. 2 out of 8 were treated conservatively. In all patients haematomas were seen in B-scan mode. No necrosis could be detected. In the TIC analysis low levels of time to peak (20.0 ± 12.1) and area under the curve (118.4 ± 87.8) were observed in acute compartment syndrome. Similarly results have been obtained using the perfusions parameter PEAK (11.1 ± 5.7), time to PEAK (14.7 ± 9.7), regional blood volume (257.1 ± 192.6), and regional blood flow (12.1 ± 6.5) in QONTRAST(®) perfusion software. CONCLUSION CEUS may be capable of differing between acute compartment syndrome and imminent compartment syndrome.

TTP (time to PEAK) and RBV (regional blood volume) as valuable parameters to detect early flap failure

BACKGROUND Free flap transplantation is used more and more frequently in order to cover extensive wound defects. The basic prerequisite for successful flap salvage after flap failure is a short time interval from failure until revision. For this reason many different flap monitoring systems have been tested over the last years. OBJECTIVE The aim of the experiment was to detect critical capillary perfusion using contrast enhanced ultrasound. Quantitative analysis should be performed by a special perfusion software (QONTRAST; Bracco, Italy) appraising digital raw data of contrast enhanced ultrasound (CEUS). Additionally diverse risk factors for free flap transplantation were determined. METHODS Thirty-one patients were examined after free flap transplantation during the first 72 hours after operation. CEUS was performed with a linear transducer (6-9 MHz, LOGIQ E9/GE) and a bolus injection of 2.4 ml of contrast agent (SonoVue, Bracco, Italy). Operation and examination were performed by either an experienced plastic surgeon or an experienced ultrasound examiner. Depth dependent capillary perfusion was analysed and quantitative perfusions analysis was performed using the perfusions software QONTRAST (Bracco, Italy). Eleven revisions had to be performed: 7 due to haematoma and 4 due to superficial necrosis. RESULTS Reduced capillary perfusion was seen in all 11 complications using CEUS. Significant difference comparing the no complication and the complication group was observed using TTP (time to PEAK) and RBV (regional blood volume) quantitative analysis. Mean RBV was 922.1 ± 150.9 in the no complication and 303.0 ± 53.9 in the complication group (p = 0.001). Mean TTP was 37.6 ± 3.8 in the no complication and 21.3 ± 3.4 in the complication group (p = 0.006). Tendency to higher complication rate was seen in older male patients with vascular or malignant primary disease. CONCLUSION In this clinical trial, capillary perfusion after free flap transplantation as well as detection of vascular complications was demonstrated using CEUS. Quantitative perfusions analysis could be performed and flap viability could be assessed easily.

Post-operative monitoring of tissue transfers: Advantages using contrast enhanced ultrasound (CEUS) and contrast enhanced MRI (ceMRI) with dynamic perfusion analysis?

BACKGROUND The immediate evaluation of microvascular tissue flaps with respect to microcirculation after transplantation is crucial for optimal monitoring and outcome. The purpose of our investigation was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced MRI (ceMRI) for monitoring the integrity of tissue flaps in plastic surgery. METHODS To this end, we investigated 10 patients (47 ± 16 a) between postoperative day 7 and 14 who underwent flap surgery in order to cover tissue defects in various body regions. For CEUS we utilized the GE LOGIQ E9 equipped with a linear transducer (6-9 MHz). After application of 2.4 ml SonoVue, the tissue perfusion was detected in Low MI-Technique (MI < 0.2). The perfusion curves were quantitatively analyzed using digital video sequences (QONTRAST, Bracco, Italy) regarding peak % and relative blood flow (RBF). Furthermore, we investigated all tissue flaps using contrast-enhanced MRI (Magnetom Symphony TIM, Siemens) with a 3D-VIBE sequence and a time resolution of 7s. Thus, the transplants were completely captured in all cases. As perfusion parameters, the positive enhancement integral (PEI) as well as the maximum intensity projection time (MIP-time) were collected. For comparison of both applications, all parameters were displayed in color-coded resolution and analyzed by three independent readers. Depending on the flap thickness, 1-3 regions of interest (ROI) were investigated. Each ROI measured 1 × 3 cm. RESULTS The subcutaneous ROI-1 showed a significantly lower rating regarding RBF in the ceMRI compared to CEUS (Mann-Whitney Rank-Sum test, p < 0.05). ROI-2 and -3 did not show any significant differences between the two applications. The frequency distribution showed good accordance in both modalities. Both imaging techniques detected 1 partial flap necrosis within the random area of cutaneous and subcutaneous layers, 1 hematoma as well as 1 insufficient perfusion over all tissue layers. After subsequent reoperation, graft loss could be prevented. CONCLUSION At present, both technologies provide an optimal assessment of perfusion in cutaneous, subcutaneous and muscle tissue layers, whereby the detection of fatty tissue perfusion is currently more easily detected using CEUS compared to ceMRI.

Procedures for ethical review for clinical trials within the EU

Despite European legislation to harmonise procedures for ethical approval, Andreas Schnitzbauer and colleagues found getting approval for their multinational study was still complex and time consuming

Evaluation of hyperbaric oxygen therapy for free flaps using planar optical oxygen sensors. Preliminary results

OBJECTIVES This study was designed to determine if a) hyperbaric oxygen increases the tissue oxygenation of free flaps and b) verification of this effect is possible by using a recently validated and innovative method for two-dimensional pO₂ measurement (Luminescence lifetime imaging = LLI). METHODS Six patients with a free parascapular flap transplanted to the lower limb received hyperbaric oxygen (HBOT) therapy. The HBOT regimen consisted of treatment over 90 minutes with 100% O₂ (FiO₂ 1.0) at 240 kPa (Marx-Schema). The transcutaneous oxygen partial pressure (ptcO₂) was measured over the entire flap with the use of luminescence lifetime imaging (LLI) before and 30, 60, 120 minutes after treatment. The LLI is based on the oxygen dependent quenching of phosphorescence of the indicator dye platinum (II)-octaethyl-porphyrin implemented in a polystyrene sensor foil. RESULTS In all six free flaps we could find a significant increase of tissue oxygen over the entire flap in form of increased R-values as well as subsequently calculated absolute ptcO₂ values over a period of 120 min after hyperbaric therapy. The ptcO₂ values increased significantly from 42.59 ± 1.11 Torr before to 81.14 ± 5.95 Torr after hyperbaric treatment (p < 0.001). Even after 2 hours the ptcO₂ values were significantly higher (83.45 ± 13.80 Torr) compared with values prior to HBOT (p < 0.006). CONCLUSIONS The findings of this study demonstrated an increase of oxygen supply over the entire flap after hyperbaric oxygen therapy.