Andreas Lutz Heinrich Gerken

Dr. Andreas Lutz Heinrich Gerken

Universität Heidelberg, Faculty of Mannheim, Mannheim, Baden-Württemberg, Germany
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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2018 in Journal of Gastrointestinal Surgery
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Journal Article
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IKIoannis Karampinis
Ioannis Karampinis
MKMichael Keese
Michael Keese
JJJens Jakob
Jens Jakob
VSVytautas Stasiunaitis
Vytautas Stasiunaitis
AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
KNKai Nowak
Kai Nowak

1 December 2017 in International Journal of Surgery
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Journal Article
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IKIoannis Karampinis
Ioannis Karampinis
Ulrich RonellenfitschUlrich Ronellenfitsch
Ulrich Ronellenfitsch
CMChristina Mertens
Christina Mertens
AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
SHSvetlana Hetjens
Svetlana Hetjens
KNKai Nowak
Kai Nowak
Optimal perfusion of the gastric conduit during esophagectomy is elementary for the anastomotic healing since poor perfusion has been associated with increased morbidity due to anastomotic leaks. Until recently surgical experience was the main tool to assess the perfusion of the anastomosis. We hypothesized that anastomoses located in the zone of optimal ICG perfusion of the gastric conduit ("optizone") have a reduced anastomotic leakage rate after esophagectomy. Indocyanine green (ICG) fluorescence tissue angiography was used to evaluate the anastomotic perfusion in 35 patients undergoing esophagectomy with gastric conduit reconstruction. The transition point of the "optizone" to the malperfused area of the conduit was defined macroscopically and with the use of ICG angiography during the operation. The anastomosis was performed in the optizone whenever possible. The results of the ICG patients were retrospectively reviewed and compared with 55 patients previously operated without ICG angiography. The visual assessment of the conduit perfusion concurred with the ICG angiography in 27 cases. In 8 cases (22.8%) the ICG angiography deviated from the visual aspect. One case of anastomotic leakage was observed in the group of patients in which the anastomosis could be performed in the optizone (1/33; 3%) compared with 10 cases in the control group (18%; p = 0.04). In two cases we had to perform the anastomosis in an area of compromised ICG perfusion. Both patients developed an anastomotic leakage. ICG tissue angiography represents a feasible and reliable technical support in the evaluation of the anastomotic perfusion after esophagectomy. In this retrospective analysis we observed a significant decrease in anastomotic leakage rate when the anastomosis could be placed in the zone of good perfusion defined by ICG fluorescence. A prospective trial is needed in order to provide higher level evidence for the use of ICG fluorescence in reducing leakage rates after esophagectomy.

15 August 2020 in Obesity Surgery
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Journal Article
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AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
KRK-K. Rohr-Kräutle
K-K. Rohr-Kräutle
CWC. Weiss
C. Weiss
SSS. Seyfried
S. Seyfried
CRC. Reissfelder
C. Reissfelder
MOM. Otto
M. Otto
Background: The amount of postoperative weight loss after bariatric surgery varies interindividually. The quality of the pre- and postoperative body composition is an important predictor of success. The aim of this study was to investigate the role of preoperative handgrip strength and phase angle (PhA) as predictors of sustained postoperative weight loss in order to assess the influence of body composition on the postoperative outcome after bariatric surgery.Method: In a prospective cohort study, bioelectrical impedance and follow-up data of 198 patients after laparoscopic sleeve gastrectomy (SG;n = 68) and Roux-en-Y gastric bypass (GB;n = 130) were analyzed for a period of 36 months postoperatively.Results: The mean preoperative handgrip strength (31.48 kg, SD 9.97) correlates significantly with the postoperative body composition up to 24 months after surgery. Preoperative PhA, gender, size, and body weight influenced postoperative weight loss significantly. A significant correlation between preoperative PhA (mean 6.18°, SD 0.89°) and total weight loss (%TWL) was observed up to 3 months after SG (r = 0.31444,p = 0.0218) and up to 12 months after GB (r = 0.19184,p = 0.0467). The optimum cutoff for the prediction of a response of less than 50% excess weight loss was a preoperative PhA of 6.0°.Conclusions: The preoperative handgrip strength confirmed its suitability for use as a predictor of postoperative body composition, whereas the preoperative PhA predicts postoperative weight loss after bariatric surgery. Further research is necessary to identify the role of these parameters for preconditioning.

30 December 2020 in Annals of Surgery
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Journal Article
Open access
AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
KNKai Nowak
Kai Nowak
AMAlexander Meyer
Alexander Meyer
CWChristel Weiss
Christel Weiss
BKBernd Krüger
Bernd Krüger
URUlrich Rother
Ulrich Rother
Objective: This study was designed to demonstrate the predictive ability of quantitative indocyanine green (ICG) fluorescence angiography for the short-term postoperative outcome, the occurrence of delayed graft function (DGF), and long-term graft survival. Summary Background Data: DGF is a relevant problem after kidney transplantation; sufficient microperfusion of the allograft is crucial for postoperative organ function. Fluorescence angiography with ICG can serve as an intraoperative quality control of microperfusion. Methods: This prospective diagnostic study, conducted in 2 German transplantation centers from November 2015 to October 2018, included 128 consecutive kidney transplantations. Intraoperative assessment of the allograft microperfusion was performed by near-infrared fluorescence angiography with ICG; a software was used for quantitative analysis. The associations between perfusion parameters (eg, ICG Ingress) and donor, recipient, peri-procedural, and postoperative characteristics were evaluated. Results: DGF occurred in 23 (24%) kidney recipients from deceased donors. ICG Ingress (P = 0.0027), donor age (P = 0.0452), recipient age (P = 0.0139), and recipient body mass index (P = 0.0017) were associated with DGF. ICG Ingress correlated significantly with recipient age (r = −0.27662, P = 0.0016), cold and warm ischemia time (r = −0.25204, P = 0.0082; r = −0.19778, P = 0.0283), operating time (r = −0.32208, P = 0.0002), eGFR on postoperative days 1 (r =+0.22674, P = 0.0104) and 7 (r = +0.33189, P = 0.0001). The cutoff value for ICG Ingress was 106.23 AU with sensitivity of 78.3% and specificity of 80.8% (P < 0.0001) for the prediction of DGF. Conclusion: Fluorescence angiography with ICG allows intraoperative quantitative assessment of microperfusion during kidney transplantation. The parameter ICG Ingress reflects recipient and procedure characteristics and is able to predict the incidence of DGF. Trial registration: Clinicaltrials.gov: NCT-02775838

8 August 2017 in Microcirculation
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URUlrich Rother
Ulrich Rother
AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
IKIoannis Karampinis
Ioannis Karampinis
MKMadeline Klumpp
Madeline Klumpp
SRSusanne Regus
Susanne Regus
KNKai Nowak
Kai Nowak

26 March 2020 in Visceral Medicine
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KNKai Nowak
Kai Nowak
IKIoannis Karampinis
Ioannis Karampinis
AGAndreas Lutz Heinrich Gerken
Andreas Lutz Heinrich Gerken
Background: Through the improvement and implementation of advanced intraoperative imaging, the indications for intraoperative fluorescence have spread to various fields of visceral surgery. Indocyanine green (ICG)-based fluorescence angiography and the imaging systems using this certain dye are currently the cornerstone of intraoperative, fluorescence-based medical imaging. Summary: The article focuses on principles and approaches of intraoperative fluorescence in general surgery. The current clinical practice of intraoperative fluorescence and its evidence are described. Emerging new fields of application are put in a perspective. Furthermore, the technique and possible pit-falls in the performance of intraoperative ICG fluorescence angiography are described in this review article. Key Messages: Overall growing evidence suggests that intraoperative fluorescence imaging delivers valuable additional information to the surgeon, which might help to perform surgery more exactly and reduce perioperative complications. Perfusion assessment can be a helpful tool when performing critical anastomoses. There is evidence from prospective and randomized trials for the benefit of intraoperative ICG fluorescence angiography during esophageal reconstruction, colorectal surgery, and surgery for mesenteric ischemia. Most studies suggest the administration of 2.5–10 mg of ICG. Standardized settings and documentation are essential. The benefit of ICG fluorescence imaging for gastrointestinal sentinel node detection and detection of liver tumors and colorectal metastases of the liver cannot clearly be estimated duo to the small number of prospective studies. Critical points in the use of intraoperative fluorescence imaging remain the low standardization and reproducibility of the results and the associated difficulty in comparing the results of the existing trials. Furthermore, little is known about the influence of hemodynamic parameters on the quantitative assessment of ICG fluorescence during surgery.