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Dive into the research topics where Frank Lenze is active.

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Featured researches published by Frank Lenze.


The American Journal of Gastroenterology | 2008

Double Balloon Enteroscopy: A Useful Tool for Diagnostic and Therapeutic Procedures in the Pancreaticobiliary System

Christian Maaser; Frank Lenze; Maja Bokemeyer; Hansjoerg Ullerich; Dirk Domagk; Matthias Bruewer; Andreas Luegering; Wolfram Domschke; Torsten Kucharzik

OBJECTIVES:Diagnostic and therapeutic interventions in the biliary and pancreatic system in the previously operated patient by conventional endoscopic retrograde cholangiopancreaticography (ERCP) are difficult and, depending on the surgical procedure, in many cases unsuccessful. We describe our experience of ERCP performed with a double balloon enteroscope (DBE) as an alternative examination technique for these patients.METHODS:In a retrospective analysis of all DBE procedures at our department between November 2004 and June 2007, 11 patients were identified with various anatomic variations in whom ERCP was performed using a DBE.RESULTS:In 72% of the patients, previous conventional ERCP examinations failed (8/11). In these patients, DBE-ERCP was successful in 63%. The overall success rate of DBE-ERCP in all patients was 64% (7/11 patients). In those patients, interventions such as papillotomy, calculus extractions, as well as stent placement could be performed even though tools for DBE-ERCP are still very limited. Despite most of the DBE-ERCPs having included therapeutic interventions, no major complications occurred in our case series and minor side effects were restricted to meteorism and mild to moderate abdominal pain.CONCLUSIONS:DBE-ERCP is an alternative method for diagnostic as well as therapeutic interventions in the biliary as well pancreatic system in the operated patient. However, it should be limited to selected patients, e.g., with contraindications for PTC, as it is a time-consuming as well as a cost-intensive procedure.


Circulation-arrhythmia and Electrophysiology | 2010

Damage to the esophagus after atrial fibrillation ablation: Just the tip of the iceberg? High prevalence of mediastinal changes diagnosed by endosonography.

Stephan Zellerhoff; Hansjörg Ullerich; Frank Lenze; Tobias Meister; Kristina Wasmer; Gerold Mönnig; Julia Köbe; Peter Milberg; Alex Bittner; Wolfram Domschke; Günter Breithardt; Lars Eckardt

Background—Radiofrequency catheter ablation is increasingly used in the treatment of atrial fibrillation. Esophageal wall changes varying from erythema to ulcers have been described by endoscopy in up to 47% of patients following pulmonary vein isolation (PVI). Although esophageal changes are frequently reported, the development of a left atrial (LA)-esophageal fistula is fortunately rare. Nevertheless, mucosal changes may just represent “the tip of the iceberg.” The aim of this study was, therefore, to investigate the more subtle changes of and injuries to the posterior wall of the LA, the periesophageal and mediastinal connective tissue, and the whole wall of the esophagus, including mucosal changes by esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS). Methods and Results—Twenty-nine patients (7 females; mean age, 57.7±10.5 years [range, 23–75 years]) underwent EGD and EUS before and after PVI within 48 hours. PVI was performed as a circumferential antral isolation of the septal and lateral pulmonary veins guided by a decapolar circular mapping catheter using a 3-dimensional mapping system with the integration of a preprocedurally acquired computed tomography scan of the left atrium. The maximum power applied was 30 W, with an open-irrigated catheter using a maximum flow rate of 30 mL/min. In all patients, the esophagus was reconstructed using the same computed tomography scan and displayed during the ablation procedure. In case of newly detected periesophageal changes, EGD and EUS were repeated 1 week after the PVI. In all patients, a regular contact area between the LA and the esophagus could be demonstrated before PVI. The mean vertical contact length was 4.4±1.5 cm (range, 2–10 cm); and the mean distance between the anterior wall of the esophagus and the endocardium was 2.6±0.8 mm (range, 1.4–4.0 mm). After PVI, morphological changes of the periesophageal connective tissue and the posterior wall of the LA were diagnosed by endosonography in 8 patients (27%; 95% confidence interval, 12.73–47.24). No mucosal changes of the esophagus in terms of erythema or ulcers were found. In all but one patient (who refused the control), all periesophageal and atrial changes had resolved within 1 week. No atrioesophageal fistula occurred during follow-up (mean follow-up, 294±110 days [range, 36–431 days]). Conclusions—Mucosal changes of the esophagus after PVI-like ulcers or erythema could not be demonstrated, yet structural changes of the mediastinum, which were only visible by endosonography, occurred in 27% of patients in the present study. This may indicate a higher than expected periesophageal injury because of PV ablation. Endosonography might prove to be a sensitive and reliable tool in the follow-up after PVI.Background— Radiofrequency catheter ablation is increasingly used in the treatment of atrial fibrillation. Esophageal wall changes varying from erythema to ulcers have been described by endoscopy in up to 47% of patients following pulmonary vein isolation (PVI). Although esophageal changes are frequently reported, the development of a left atrial (LA)-esophageal fistula is fortunately rare. Nevertheless, mucosal changes may just represent “the tip of the iceberg.” The aim of this study was, therefore, to investigate the more subtle changes of and injuries to the posterior wall of the LA, the periesophageal and mediastinal connective tissue, and the whole wall of the esophagus, including mucosal changes by esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS). Methods and Results— Twenty-nine patients (7 females; mean age, 57.7±10.5 years [range, 23–75 years]) underwent EGD and EUS before and after PVI within 48 hours. PVI was performed as a circumferential antral isolation of the septal and lateral pulmonary veins guided by a decapolar circular mapping catheter using a 3-dimensional mapping system with the integration of a preprocedurally acquired computed tomography scan of the left atrium. The maximum power applied was 30 W, with an open-irrigated catheter using a maximum flow rate of 30 mL/min. In all patients, the esophagus was reconstructed using the same computed tomography scan and displayed during the ablation procedure. In case of newly detected periesophageal changes, EGD and EUS were repeated 1 week after the PVI. In all patients, a regular contact area between the LA and the esophagus could be demonstrated before PVI. The mean vertical contact length was 4.4±1.5 cm (range, 2–10 cm); and the mean distance between the anterior wall of the esophagus and the endocardium was 2.6±0.8 mm (range, 1.4–4.0 mm). After PVI, morphological changes of the periesophageal connective tissue and the posterior wall of the LA were diagnosed by endosonography in 8 patients (27%; 95% confidence interval, 12.73–47.24). No mucosal changes of the esophagus in terms of erythema or ulcers were found. In all but one patient (who refused the control), all periesophageal and atrial changes had resolved within 1 week. No atrioesophageal fistula occurred during follow-up (mean follow-up, 294±110 days [range, 36–431 days]). Conclusions— Mucosal changes of the esophagus after PVI-like ulcers or erythema could not be demonstrated, yet structural changes of the mediastinum, which were only visible by endosonography, occurred in 27% of patients in the present study. This may indicate a higher than expected periesophageal injury because of PV ablation. Endosonography might prove to be a sensitive and reliable tool in the follow-up after PVI. Received October 19, 2009; accepted February 16, 2010. # CLINICAL PERSPECTIVE {#article-title-2}


Inflammatory Bowel Diseases | 2012

Detection and differentiation of inflammatory versus fibromatous Crohn's disease strictures: prospective comparison of 18F-FDG-PET/CT, MR-enteroclysis, and transabdominal ultrasound versus endoscopic/histologic evaluation.

Frank Lenze; Johannes Wessling; Janbernd Bremer; Hansjoerg Ullerich; Tillmann Spieker; Matthias Weckesser; Sarid Gonschorrek; Klaus Kannengieβer; Emile Rijcken; Jan Heidemann; Andreas Luegering; Otmar Schober; Wolfram Domschke; Torsten Kucharzik; Christian Maaser

Background: Differentiation between inflammatory and fibromatous strictures in Crohns disease (CD) is difficult but crucial for therapeutic decisions. The aim of this study was to assess the best noninvasive imaging method for the detection and differentiation of inflammatory and fibromatous stenoses in CD in comparison to endoscopic and histologic evaluation. Methods: Patients with suspected CD strictures were included. According to a formalized endoscopic and histologic protocol, strictures were classified as inflammatory, mixed, and fibrostenotic. Strictures were further analyzed using fluorine 18‐labeled fluoro‐2‐deoxy‐D‐glucose (18FDG) / positron emission tomography (PET) low‐dose computed tomography (CT), magnetic resonance (MR) enteroclysis and transabdominal ultrasound using standardized scoring systems. Results: Thirty patients with 37 strictures were evaluated (inflamed n = 22; mixed n = 12, fibromatous n = 3). 18FDG‐PET/CT detected 81%, MR‐enteroclysis 81%, and ultrasound 68% of the strictures. Correct differentiation rates of strictures were 57% for MRE, 53% for 18FDG‐PET/CT, and 40% for ultrasound. Differences of detection rates and differentiation rates were not statistically significant. When combining transabdominal ultrasound with 18FDG‐PET/CT or MR‐enteroclysis all strictures that required invasive treatment were detected. Conclusions: Detection rates of the strictures were not significantly different between 18FDG‐PET/CT, MR‐enteroclysis, and ultrasound. Despite good stricture detection rates relating to our gold standard, 18FDG‐PET/CT nor MR‐enteroclysis nor ultrasound can accurately differentiate inflamed from fibrotic strictures. A combination of MR‐enteroclysis and ultrasound as well as a combination of 18FDG‐PET/CT and ultrasound resulted in a 100% detection rate of strictures requiring surgery or endoscopic dilation therapy, suggesting the combination of these methods as an alternative to endoscopy at least in the group of patients not able to perform an adequate bowel preparation. (Inflamm Bowel Dis 2012;)


Cancer | 2008

Undifferentiated embryonal sarcoma of the liver in adults

Frank Lenze; Traute Birkfellner; Philipp Lenz; Kais Hussein; Florian Länger; Hans Kreipe; Wolfram Domschke

Undifferentiated embryonal sarcoma of the liver (UESL), a rare tumor that predominantly affects children, generally has been considered an aggressive neoplasm with an unfavorable prognosis. More recent reports have indicated that modern multimodal treatment and supportive care improve the survival of children with UESL. Data regarding the treatment and survival of adults have not been reviewed comprehensively, and only a few adult patients with UESL have been reported in the literature.


Europace | 2011

Prophylactic proton pump inhibition after atrial fibrillation ablation: is there any evidence?

Stephan Zellerhoff; Frank Lenze; Lars Eckardt

The development of an atrio-oesophageal fistula following catheter ablation for atrial fibrillation is a well known, but rare complication with a high mortality, partially due to the late fistula formation weeks after the initial procedure. Technical measurements are undertaken to avoid oesophageal damage during catheter ablation of atrial fibrillation, yet, oesophageal and mediastinal lesions occur in a substantial number of patients following pulmonary vein isolation. This has led to prophylactic use of proton pump inhibitors in many centres. Current guidelines and consensus reports list no objectives on this issue. The aim of the paper is therefore to review current clinical and experimental evidence for this treatment.


The Journal of Nuclear Medicine | 2013

Translational 18F-FDG PET/CT Imaging to Monitor Lesion Activity in Intestinal Inflammation

Stefan Reuter; Sven Hermann; Matthias Weckesser; Linda Kerstiens; Athanasios Stratis; Tobias M. Nowacki; Matthias Ross; Frank Lenze; Bayram Edemir; Christian Maaser; Thomas Pap; Steffen Koschmieder; Jan Heidemann; Michael Schäfers; Andreas Lügering

In patients with inflammatory bowel disease (IBD) and in murine IBD models, mucosal disease activity is routinely assessed by endoscopy and histologic evaluation. This information is valuable for monitoring treatment response, with mucosal healing being a major treatment goal. The aim of this study was to evaluate the translational potential of noninvasive 18F-FDG PET/CT for the assessment of mucosal damage in murine dextran sodium sulfate (DSS) colitis and human IBD. Methods: After induction of DSS colitis, 18F-FDG uptake was serially assessed from colonic volumes of interest defined on PET/CT scans and intraindividually correlated to histologic findings and to infiltrating cell types. In addition, 18F-FDG PET/CT scans of 25 Crohn disease patients were analyzed, and colonic 18F-FDG uptake was correlated to endoscopically assessed damage. Results: At days 4 and 7 after DSS induction, colonic 18F-FDG uptake was significantly increased, with a distinct peak in the medial colon. 18F-FDG uptake strongly correlated with histologic epithelial damage. Additionally, 18F-FDG uptake increased in the bone marrow in the course of the disease, correlating with an increase in intestinal 18F-FDG uptake. Histology and fluorescence-activated cell sorting analysis of the bone marrow of DSS mice revealed an increased number of immature neutrophils, whereas mucosal polymerase chain reaction suggested a correlation of 18F-FDG uptake to T cell infiltration. In accordance with the results of 18F-FDG PET/CT in DSS colitis, an increased 18F-FDG uptake was found in 87% of deep mucosal ulcerations in IBD patients, whereas mild endoscopic lesions were detected only by 18F-FDG PET/CT in about 50% of patients assessed. Conclusion: 18F-FDG PET/CT is a noninvasive method for evaluation of both experimental colitis and Crohn disease patients and thereby offers promising translational potential.


Scandinavian Journal of Gastroenterology | 2011

Single-step versus multi-step transmural drainage of pancreatic pseudocysts: the use of cystostome is effective and timesaving.

Hauke Heinzow; Tobias Meister; Benjamin Pfromm; Frank Lenze; Wolfram Domschke; Hansjoerg Ullerich

Abstract Background and aims. Pancreatic pseudocysts are a major complication of chronic and acute pancreatitis and often require endoscopic intervention. Endoscopic single-step and multi-step transmural drainage techniques have been reported in the literature. The aim of this study was to evaluate and compare technical results and clinical outcome rates of the single-step versus multi-step endoscopic ultrasonography (EUS)-guided endoscopic transmural drainage in patients with symptomatic pancreatic pseudocysts of >4 cm size. Design. Retrospective study at an academic tertiary referral center. Patients and methods. A total of 38 consecutive patients comprising 42 interventions were studied: 16 patients with pancreatic pseudocysts (18 interventions) had undergone single-step EUS-guided transmural cystostome drainage between 2007 and 2010. Results were compared with a cohort of 22 patients who had submitted to multi-step EUS-guided transmural drainage of pancreatic pseudocysts in 24 cases between 2005 and 2007. Results. The technical success rate for using the single-step procedure was 94% compared with multi-step procedure with 83% (n.s.). Primary clinical success rate was 88% for single-step drainage and 90% for the multi-step approach (n.s.). The mean procedure time was 36 ± 9 min in the single-step group compared with 62 ± 12 min for the multi-step access (p < 0.001). Conclusions. The use of single-step cystostome appears useful in managing selected patients with symptomatic pancreatic pseudocysts as it is effective and timesaving.


Endoscopy | 2013

CO2 insufflation during single-balloon enteroscopy: a multicenter randomized controlled trial.

Philipp Lenz; Tobias Meister; Mauro Manno; Marco Pennazio; Rita Conigliaro; Sven Lebkücher; Hansjoerg Ullerich; Andre Schmedt; Martin Floer; Torsten Beyna; Frank Lenze; Dirk Domagk

BACKGROUND AND STUDY AIMS Carbon dioxide (CO2) insufflation has previously been shown to have advantages over air insufflation in terms of procedure-related pain and oral insertion depth during double-balloon enteroscopy. The aim of this prospective study was to evaluate the performance of CO2 vs. air insufflation during single-balloon enteroscopy. PATIENTS AND METHODS This study was a randomized European multicenter trial (ClinicalTrials.gov: NCT01524055). Patients and endoscopists were blinded to the type of insufflation gas used. Patient discomfort during and after the procedure was scored using a visual analog scale. RESULTS A total of 107 patients were enrolled in the study (52 in the CO2 group and 55 in the air group). Patient characteristics were comparable in both groups. The mean (±SD) oral intubation depth was not significantly deeper in the CO2 group vs. the air group (254±80 vs. 238±55 cm; P=0.726). However, in patients with previous abdominal surgery, oral intubation depth was significantly higher in the CO2 group compared with the air group (258±84 vs. 192±42 cm; P<0.05). In patients undergoing SBE via the anal approach, CO2 showed no significant difference in intubation depth compared with air insufflation (86±67 vs. 110±68 cm; P=0.155). The diagnostic yield was comparable (CO2 67%; air 73%). Procedure times, dosage of sedation, and therapeutic interventions did not differ between the two groups. Patients in the CO2 group reported less pain than those in the air group. CONCLUSIONS This study demonstrated an advantage of using CO2 insufflation during single-balloon enteroscopy in patients with a history of previous abdominal surgery. Overall, single-balloon enteroscopy was a well-tolerated procedure that may benefit from the use of CO2 insufflation to reduce post-procedural pain.


World Journal of Gastroenterology | 2016

Assessment of stricturing Crohn's disease: Current clinical practice and future avenues

Tobias M. Nowacki; Friederike Cordes; Boris Buerke; Frank Lenze

Crohns disease (CD) is a chronic remittent idiopathic disease. Although the early phase of the disease is commonly characterized by inflammation-driven symptoms, such as diarrhea, the frequency of fibrostenotic complications in patients with CD increases over the long-term course of the disease. This review presents the current diagnostic options for assessing CD-associated strictures. In addition to the endoscopic evaluation of CD strictures, this review summarizes the currently available imaging modalities, including ultrasound and cross-sectional imaging techniques. In addition to stricture detection, differentiating between the primarily inflammatory strictures and the predominantly fibrotic ones is essential for selecting the appropriate treatment strategy (anti-inflammatory medical treatment vs endoscopical or surgical approaches). Therefore, recent imaging advances, such as contrast-enhanced ultrasound and ultrasound elastography, contribute to the development of non-invasive non-radiating imaging of CD-associated strictures. Finally, novel magnetic resonance imaging techniques, such as diffusion-weighted, motility and magnetization transfer imaging, as well as (18)F-FDG PET/CT, molecular imaging approaches and biomarkers, are critically reviewed with regard to their potential role in assessing stricturing CD.


European Journal of Human Genetics | 2016

The HLA-DQβ1 insertion is a strong achalasia risk factor and displays a geospatial north–south gradient among Europeans

Jessica Becker; Stephan L. Haas; Anna Mokrowiecka; Justyna Wasielica-Berger; Zeeshan Ateeb; Jonna Bister; Peter Elbe; Marek L. Kowalski; Magdalena Gawron-Kiszka; Marek Majewski; Agata Mulak; Maria Janiak; Mira M. Wouters; Till Schwämmle; Timo Hess; Lothar Veits; Stefan Niebisch; José L. Santiago; Antonio Ruiz de León; Julio Pérez de la Serna; Elena Urcelay; Vito Annese; Anna Latiano; Uberto Fumagalli; Riccardo Rosati; Luigi Laghi; Rosario Cuomo; Frank Lenze; Giovanni Sarnelli; Michaela Müller

Idiopathic achalasia is a severe motility disorder of the esophagus and is characterized by a failure of the lower esophageal sphincter to relax due to a loss of neurons in the myenteric plexus. Most recently, we identified an eight-amino-acid insertion in the cytoplasmic tail of HLA-DQβ1 as strong achalasia risk factor in a sample set from Central Europe, Italy and Spain. Here, we tested whether the HLA-DQβ1 insertion also confers achalasia risk in the Polish and Swedish population. We could replicate the initial findings and the insertion shows strong achalasia association in both samples (Poland P=1.84 × 10−04, Sweden P=7.44 × 10−05). Combining all five European data sets – Central Europe, Italy, Spain, Poland and Sweden – the insertion is achalasia associated with Pcombined=1.67 × 10−35. In addition, we observe that the frequency of the insertion shows a geospatial north–south gradient. The insertion is less common in northern (around 6–7% in patients and 2% in controls from Sweden and Poland) compared with southern Europeans (~16% in patients and 8% in controls from Italy) and shows a stronger attributable risk in the southern European population. Our study provides evidence that the prevalence of achalasia may differ between populations.

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Dirk Domagk

University of Münster

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Tobias Meister

University of Göttingen

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