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Dive into the research topics where Dirk Loßnitzer is active.

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Featured researches published by Dirk Loßnitzer.


International Journal of Cardiology | 2016

Characteristics and long-term outcome of right ventricular involvement in Takotsubo cardiomyopathy

Tobias Becher; Ibrahim El-Battrawy; Stefan Baumann; Christian Fastner; Michael Behnes; Dirk Loßnitzer; Elif Elmas; Ursula Hoffmann; Theano Papavassiliu; Jürgen Kuschyk; Christina Dösch; Susanne Röger; Dennis Hillenbrand; Katja Schramm; Martin Borggrefe; Ibrahim Akin

OBJECTIVE Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy (SCM) resembles a reversible cardiomyopathy that is characterized by localized wall motion abnormalities in the absence of stenotic coronary vascular disease. Patients typically present with apical ballooning of the left ventricle (LV), however the right ventricle (RV) is also affected in up to 50.0% of patients. Long-term prognosis of classical SCM resembles that of patients after ST elevation myocardial infarction. Data on long-term prognosis of biventricular compared to classical SCM is controversial. The aim of this study was therefore to analyze patients with biventricular SCM regarding in-hospital outcome and long-term prognosis. MATERIALS AND METHODS 114 consecutive patients with SCM were retrospectively analyzed. 88 patients presented with classical SCM, 26 patients (22.8%) were diagnosed with biventricular SCM. Follow-up was conducted for a total of 4.4years. Mean age was 67.1years with 83.3% of patients being female. The primary endpoint was a composite of all-cause mortality, recurrence of SCM and re-hospitalization due to heart failure. RESULTS Although patients with biventricular SCM presented with a tendency towards an increased rate of cardiogenic shock (30.8% vs. 15.9%; p=0.09) and significantly more usage of inotropic support upon hospital admission (34.6% vs. 13.6%; p=0.01), there was no difference concerning the primary endpoint in both groups (50.0% vs. 44.3%; p=0.31). Furthermore, there was no difference in mortality both in-hospital (7.7% vs. 7.9%; p=0.66) and during long-term follow-up (27.3% vs. 23.1%; p=0.46). CONCLUSION Patients with biventricular SCM have the same in-hospital and long-term outcome compared to classical SCM.


International Journal of Cardiology | 2015

Reference values for left and right ventricular trabeculation and non-compacted myocardium

Florian Andre; Astrid Burger; Dirk Loßnitzer; Sebastian J. Buss; Hassan Abdel-Aty; Evangelos Gianntisis; Henning Steen; Hugo A. Katus

BACKGROUND Since the differentiation between physiological and pathological trabeculation is challenging, we assessed its distribution in a reference population of selected healthy volunteers. METHODS We studied 117 subjects (58 males) stratified into age tertiles and by gender. Cardiovascular magnetic resonance images were acquired using a standard SSFP-sequence. Left and right ventricular (LV/RV) end-diastolic (EDV), end-systolic (ESV) and trabeculated volumes indexed to the body surface area as well as ejection fraction (EF) were quantified in short-axis views. The maximum non-compacted-to-compacted (NC/C) ratio was measured in long-axis views. RESULTS The trabeculated volumes were significantly larger in men than in women and decreased with age. The correlation between both was moderate (r=0.46; p<0.001). LV trabeculated volume was positively associated with EDV and ESV (r=0.74; r=0.59; both p<0.001) and negatively with EF (r=-0.27; p<0.005). It was no independent predictor for EF. The maximum NC/C ratio was >2.3 in 46.2% and >2.5 in 37.6% of the subjects, which is regarded as abnormal in current literature. The fraction of subjects with a maximum NC/C ratio >2.3 and the mean maximum NC/C ratio differed significantly between gender but not between age groups. An increasing NC/C ratio was associated with a significant decrease in EF (r=-0.21; p<0.05). CONCLUSION A considerable amount of healthy volunteers fulfils the current diagnostic criteria of LV noncompaction with female subjects showing a higher fraction of false-positive results than males. LV trabeculated volume is more pronounced in young subjects and declines with age. The use of age- and gender-specific reference values as provided in this study may facilitate the delineation of physiological and pathological findings.


Academic Radiology | 2016

Comparison of Coronary Computed Tomography Angiography-Derived vs Invasive Fractional Flow Reserve Assessment: Meta-Analysis with Subgroup Evaluation of Intermediate Stenosis

Stefan Baumann; Matthias Renker; Svetlana Hetjens; Stephen R. Fuller; Tobias Becher; Dirk Loßnitzer; Ralf Lehmann; Ibrahim Akin; Martin Borggrefe; Siegfried Lang; Julian L. Wichmann; U. Joseph Schoepf

RATIONALE AND OBJECTIVES Invasive coronary angiography (ICA) with fractional flow reserve (FFR) assessment is the reference standard for the detection of hemodynamically relevant coronary lesions. We have investigated whether coronary computed tomography angiography (cCTA)-derived FFR (fractional flow reserve from coronary computed tomographic angiography [CT-FFR]) measurement improves diagnostic accuracy over cCTA. METHODS AND RESULTS A literature search was performed for studies comparing invasive FFR, cCTA, and CT-FFR. The analysis included three prospective multicenter trials and two retrospective single-center studies; a total of 765 patients and 1306 vessels were included in the meta-analysis. Compared to invasive FFR on a per-lesion basis, CT-FFR reached a pooled sensitivity, specificity, positive predictive value, and negative predictive value of 83.7% (95% confidence interval [CI]: 78.1-89.3), 74.7% (95% CI: 52.2-97.1), 64.8% (95% CI: 52.1-77.5), and 90.1% (95% CI: 80.8-99.3) compared to 84.6% (95% CI: 78.1-91.1), 49.7% (95% CI: 31.1-68.4), 39.0% (95% CI: 28.0-50.1), and 87.3% (95% CI: 72.5-100.0) for cCTA alone. In 634 vessels with intermediate stenosis (30%-70%), sensitivity, specificity, positive predictive value, and negative predictive value were 81.4% (95% CI: 70.4-92.9), 71.7% (95% CI: 54.5-89.0), 59.4% (95% CI: 35.5-83.4), and 89.9% (95% CI: 85.0-94.7) compared to 90.2% (95% CI: 80.6-99.9), 35.4% (95% CI: 23.5-47.3), 50.7% (95% CI: 30.6-70.8), and 82.5% (95% CI: 64.5-100.0) for cCTA alone. The summary area under the receiver operating characteristic curve of CT-FFR was superior to cCTA alone on a per-vessel (0.90 [95% CI: 0.82-0.98] vs 0.74 [95% CI: 0.63-0.86]; P = .0047) and for intermediate stenoses (0.76 [95% CI: 0.65-0.88] vs 0.57 [95% CI: 0.49-0.66]; P = .0027). CONCLUSION CT-FFR significantly improves specificity without noticeably altering the sensitivity of cCTA with invasive FFR as a reference standard for the detection of hemodynamically relevant stenosis.


European heart journal. Acute cardiovascular care | 2017

Comparison of peri and post-procedural complications in patients undergoing revascularisation of coronary artery multivessel disease by coronary artery bypass grafting or protected percutaneous coronary intervention with the Impella 2.5 device

Tobias Becher; Stefan Baumann; Frederik Eder; Simon Perschka; Dirk Loßnitzer; Christian Fastner; Michael Behnes; Christina Doesch; Martin Borggrefe; Ibrahim Akin

Background: While coronary artery bypass grafting remains the standard treatment of complex multivessel coronary artery disease, the advent of peripheral ventricular assist devices has enhanced the safety of percutaneous coronary intervention. We therefore evaluated the safety in terms of inhospital outcome comparing protected high-risk percutaneous coronary intervention with the Impella 2.5 device and coronary artery bypass grafting in patients with complex multivessel coronary artery disease. Methods: This retrospective study included patients with complex multivessel coronary artery disease (SYNTAX score >22) undergoing either coronary artery bypass grafting before the implementation of a protected percutaneous coronary intervention programme with a peripheral ventricular assist device or protected percutaneous coronary intervention with the Impella 2.5 device following the start of the programme. The primary endpoint consisted of inhospital major adverse cardiac and cerebrovascular events. The combined secondary endpoint included peri and post-procedural adverse events. Results: A total of 54 patients (mean age 70.1±9.9 years, 92.6% men) were enrolled in the study with a mean SYNTAX score of 34.5±9.8. Twenty-six (48.1%) patients underwent protected percutaneous coronary intervention while 28 (51.9%) patients received coronary artery bypass grafting. The major adverse cardiac and cerebrovascular event rate was numerically higher in the coronary artery bypass grafting group (17.9 vs. 7.7%; P=0.43) but was not statistically significant. The combined secondary endpoint was not different between the groups; however, patients undergoing coronary artery bypass grafting experienced significantly more peri-procedural adverse events (28.6 vs. 3.8%; P<0.05). Conclusion: Patients with complex multivessel coronary artery disease undergoing protected percutaneous coronary intervention with the Impella 2.5 device experience similar intrahospital major adverse cardiac and cerebrovascular event rates when compared to coronary artery bypass grafting. Protected percutaneous coronary intervention represents a safe alternative to coronary artery bypass grafting in terms of inhospital adverse events.


Medizinische Klinik | 2016

[Acute pulmonary embolism and contraindication of anticoagulation : Bedside implantation of a new temporary vena cava inferior filter].

Stefan Baumann; Tobias Becher; C. Jabbour; Christian Fastner; Konstantinos Giannakopoulos; Michael Behnes; Thomas Henzler; Angelika Alonso; S. Britsch; Dirk Loßnitzer; Martin Borggrefe; Ibrahim Akin

Pulmonary embolism (PE), mostly caused by deep vein thrombosis, is a life-threatening complication in critically ill patients in the intensive care unit. A potential strategy to prevent PE in patients with contraindication for anticoagulant therapy is the implantation of a vena cava filter (VCF), to provide fast and safe PE protection against ascending thrombi. We report the case of a 56-year-old woman with an intracranial hemorrhage, who developed a PE. Because of acute contraindications for anticoagulant therapy, bedside implantation of a new VCF was performed to overcome the period of absolute contraindications for anticoagulation. After explanation, several thrombi were found on the filter.ZusammenfassungLungenarterienembolien (LE) sind lebensgefährliche Komplikationen, häufig bedingt durch tiefe Beinvenenthrombosen bei kritisch kranken Patienten auf Intensivstationen. Bei Vorliegen von Kontraindikationen gegenüber einer Antikoagulation stellt die Implantation eines V.-cava-Filters (VCF) eine mögliche Alternative zur Prophylaxe einer LE dar. Sie kann Schutz vor aszendierenden Thromben bieten. Wir berichten über den Fall einer 56-jährigen Patientin mit intrazerebraler Blutung, die eine 2‑malige zentrale LE erlitt. Bei Kontraindikation einer aktuellen Antikoagulation erfolgte die bettseitige Implantation eines neuartigen VCF bis zur Überbrückung der Kontraindikationsphase für Antikoagulation. Bei Entfernung konnten mehrere Thromben im Nitinolgerüst des VCF nachgewiesen werden.AbstractPulmonary embolism (PE), mostly caused by deep vein thrombosis, is a life-threatening complication in critically ill patients in the intensive care unit. A potential strategy to prevent PE in patients with contraindication for anticoagulant therapy is the implantation of a vena cava filter (VCF), to provide fast and safe PE protection against ascending thrombi. We report the case of a 56-year-old woman with an intracranial hemorrhage, who developed a PE. Because of acute contraindications for anticoagulant therapy, bedside implantation of a new VCF was performed to overcome the period of absolute contraindications for anticoagulation. After explanation, several thrombi were found on the filter.


Medizinische Klinik | 2017

Akute Lungenembolie und Kontraindikation für eine Antikoagulation

Stefan Baumann; Tobias Becher; C. Jabbour; Christian Fastner; Konstantinos Giannakopoulos; Michael Behnes; Thomas Henzler; Angelika Alonso; S. Britsch; Dirk Loßnitzer; Martin Borggrefe; Ibrahim Akin

Pulmonary embolism (PE), mostly caused by deep vein thrombosis, is a life-threatening complication in critically ill patients in the intensive care unit. A potential strategy to prevent PE in patients with contraindication for anticoagulant therapy is the implantation of a vena cava filter (VCF), to provide fast and safe PE protection against ascending thrombi. We report the case of a 56-year-old woman with an intracranial hemorrhage, who developed a PE. Because of acute contraindications for anticoagulant therapy, bedside implantation of a new VCF was performed to overcome the period of absolute contraindications for anticoagulation. After explanation, several thrombi were found on the filter.ZusammenfassungLungenarterienembolien (LE) sind lebensgefährliche Komplikationen, häufig bedingt durch tiefe Beinvenenthrombosen bei kritisch kranken Patienten auf Intensivstationen. Bei Vorliegen von Kontraindikationen gegenüber einer Antikoagulation stellt die Implantation eines V.-cava-Filters (VCF) eine mögliche Alternative zur Prophylaxe einer LE dar. Sie kann Schutz vor aszendierenden Thromben bieten. Wir berichten über den Fall einer 56-jährigen Patientin mit intrazerebraler Blutung, die eine 2‑malige zentrale LE erlitt. Bei Kontraindikation einer aktuellen Antikoagulation erfolgte die bettseitige Implantation eines neuartigen VCF bis zur Überbrückung der Kontraindikationsphase für Antikoagulation. Bei Entfernung konnten mehrere Thromben im Nitinolgerüst des VCF nachgewiesen werden.AbstractPulmonary embolism (PE), mostly caused by deep vein thrombosis, is a life-threatening complication in critically ill patients in the intensive care unit. A potential strategy to prevent PE in patients with contraindication for anticoagulant therapy is the implantation of a vena cava filter (VCF), to provide fast and safe PE protection against ascending thrombi. We report the case of a 56-year-old woman with an intracranial hemorrhage, who developed a PE. Because of acute contraindications for anticoagulant therapy, bedside implantation of a new VCF was performed to overcome the period of absolute contraindications for anticoagulation. After explanation, several thrombi were found on the filter.


Scientific Reports | 2018

Saturation-Recovery Myocardial T 1 -Mapping during Systole: Accurate and Robust Quantification in the Presence of Arrhythmia

Nadja M. Meßner; Johannes Budjan; Dirk Loßnitzer; Theano Papavassiliu; Lothar R. Schad; Sebastian Weingärtner; Frank G. Zöllner

Myocardial T1-mapping, a cardiac magnetic resonance imaging technique, facilitates a quantitative measure of fibrosis which is linked to numerous cardiovascular symptoms. To overcome the problems of common techniques, including lack of accuracy and robustness against partial-voluming and heart-rate variability, we introduce a systolic saturation-recovery T1-mapping method. The Saturation-Pulse Prepared Heart-rate independent Inversion-Recovery (SAPPHIRE) T1-mapping method was modified to enable imaging during systole. Phantom measurements were used to evaluate the insensitivity of systolic T1-mapping towards heart-rate variability. In-vivo feasibility and accuracy were demonstrated in ten healthy volunteers with native and post-contrast T1-mappping during systole and diastole. To show benefits in the presence of RR-variability, six arrhythmic patients underwent native T1-mapping. Resulting systolic SAPPHIRE T1-values showed no dependence on arrhythmia in phantom (CoV < 1%). In-vivo, significantly lower T1 (1563 ± 56 ms, precision: 84.8 ms) and ECV-values (0.20 ± 0.03) than during diastole (T1 = 1580 ± 62 ms, p = 0.0124; precision: 60.2 ms, p = 0.03; ECV = 0.21 ± 0.03, p = 0.0098) were measured, with a strong correlation of systolic and diastolic T1 (r = 0.89). In patients, mis-triggering-induced motion caused significant imaging artifacts in diastolic T1-maps, whereas systolic T1-maps displayed resilience to arrythmia. In conclusion, the proposed method enables saturation-recovery T1-mapping during systole, providing increased robustness against partial-voluming compared to diastolic imaging, for the benefit of T1-measurements in arrhythmic patients.


Journal of Critical Care | 2018

The evolution of activated protein C plasma levels in septic shock and its association with mortality: A prospective observational study

Tobias Becher; Jens Müller; Ibrahim Akin; Stefan Baumann; Katharina Bosch; Ksenija Stach; Martin Borggrefe; Bernd Pötzsch; Dirk Loßnitzer

Purpose: Septic shock is commonly associated with hemostatic abnormalities. The endothelium‐activated serine protease activated protein C (APC) plays a pivotal role in limiting coagulation and possesses anti‐apoptotic and anti‐inflammatory properties. We hypothesized that APC levels correlate with established coagulation parameters and provide prognostic information in patients with septic shock. Methods: We conducted a prospective, observational cohort study in patients with septic shock. APC was measured on admission (day 0) and on days 1, 3, and 6 by a clinically applicable oligonucleotide (aptamer)‐based enzyme‐capture assay (OECA). The primary endpoint was defined as sepsis‐associated 30‐day mortality. Furthermore, we analyzed the correlation of APC levels with established coagulation markers. Results: 48 consecutive patients admitted with septic shock were included (mortality 39.6%). APC levels were elevated upon admission (0.59 ng/ml, IQR 0.26–0.97) and showed a strong correlation with established markers of coagulation and lactate. Multivariable logistic regression identified APC (OR 4.3, 95% CI 1.1–17.8, p = 0.04) and lactate levels (OR 7.0, 95% CI 4.1–18.2, p = 0.04) as independent predictors of 30‐day mortality. Conclusions: APC levels are increased in patients with septic shock and are correlated with established markers of coagulation. Elevated APC levels on admission are an independent predictor of mortality. HighlightsLevels of endogenous APC are elevated during early septic shock.Endogenous APC is an independent predictor of mortality in septic shock.Lactate and APC levels demonstrate a significant correlation.Tissue hypoperfusion is associated with the activation of the protein C/APC system.


Archive | 2017

Peripheral Ventricular Assist Devices in Interventional Cardiology: The Impella® Micro-Axial Pump

Tobias Becher; Stefan Baumann; Frederik Eder; Christian Fastner; Michael Behnes; Dirk Loßnitzer; Christina Dösch; MartinBorggrefe

Coronary artery disease (CAD) presents an ever-growing burden on health systems especially in the Western world. While percutaneous coronary intervention (PCI) is feasible in increasingly complex CAD, certain patient groups possess a high risk for major cardiac adverse events (MACE) during PCI. Poor outcome is associated with significantly depressed left ventricular function, complexity of relevant lesions, and increasing incidence of pre-existing cerebrovascular comorbidities and poor pre-interventional status. However, these risk factors also translate into a high peri-operative risk for coronary artery bypass graft (CABG) rendering some of these patients inoperable. Peripheral ventricular assist devices (pVADs) are temporarily inserted axial or centrifugal pumps that support ventricular output during PCI. The Impella® micro-axial device (Abiomed, Danvers, Massachusetts, USA) is an easily implantable pVAD that may improve patient outcome during PCI in high-risk patients (termed “protected PCI”) and in patients with cardiogenic shock (CS). pVADs in general and the Impella® system in particular play important roles in interventional cardiology and its indications and use will likely expand in the future. This chapter outlines in detail the indications, applications, and future trends concerning the Impella® system. Practical advice is given on the correct implantation of the device.


Cardiology in The Young | 2017

Dynamic four-dimensional CT angiography for the assessment of pulmonary perfusion in an adult patient with pulmonary artery occlusion and major aortopulmonary collateral after multistage repair of Fallot’s Pentalogy

Dirk Loßnitzer; Stefan Baumann; Thomas Henzler

Dynamic CT angiography provides haemodynamic assessment combined with detailed information on complex cardiac anatomy in patients with congenital malformations such as multistage correction of Fallots Pentalogy.

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