Joachim Saur

Publications (15)47.14 Total impact

• Article: Evaluation of aortic valve stenosis using a hybrid approach of Doppler echocardiography and inert gas rebreathing.

  Karsten Hamm, Frederik Trinkmann, Felix Heggemann, Joachim Gruettner, Gerald Schmid-Bindert, Martin Borggrefe, Dariusch Haghi, Joachim Saur
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  ABSTRACT: Doppler echocardiography is the method of choice for diagnosis and evaluation of aortic stenosis. However, there are well-known limitations to this method in difficult-to-image patients. Flow acceleration in the left ventricular outflow tract (LVOT) can lead to overestimation of stroke volume (SV) and poor acoustic windows may impede the exact measurement of the LVOT. The present study aimed to evaluate the use of inert gas rebreathing (IGR)-derived SV in this situation. We replaced Doppler-derived SV measurements in the continuity equation (method A) by SV determined by IGR (method B) and by thermodilution during right heart catheterization (method C) to calculate the aortic valve area (AVA) in 21 consecutive patients with moderate or severe aortic stenosis. Mean SV and AVA did not differ between methods at 72±21 ml and 0.71±0.2 cm(2) (method A) vs. 66±18 ml and 0.67±0.21 cm(2) (method B) vs. 64±15 ml and 0.67±0.21 cm(2) (method C), respectively (all p-values >0.05). The mean difference and limits of agreement for AVA were 0.04±0.23 cm(2) and -0.40 to 0.47 cm(2) between methods A and B, 0.05±0.14 cm(2) and -0.26 to 0.27 cm(2) between A and C, and -0.05±0.23 cm(2) and -0.45 to 0.35 cm(2) between B and C, respectively (all p-values >0.05). The presented approach is a reliable method for the calculation of AVA and can add a diagnostic option for the use in difficult-to-image patients. Whereas the use of thermodilution is limited due to its invasive nature, IGR allows the fast and non-invasive determination of cardiac function at low cost.
  In vivo (Athens, Greece) 11/2012; 26(6):1027-33. · 1.17 Impact Factor
• Article: Is Arterial Pulse Contour Analysis Using Nexfin a New Option in the Noninvasive Measurement of Cardiac Output?-A Pilot Study.

  Frederik Trinkmann, Matthias Sampels, Christina Doesch, Theano Papavassiliu, Joachim Brade, Gerald Schmid-Bindert, Ursula Hoffmann, Martin Borggrefe, Jens J Kaden, Joachim Saur
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  ABSTRACT: OBJECTIVES: A growing interest in monitoring cardiac output (CO) noninvasively has emerged; however, its determination has been difficult using the standard approaches. The aim of this study was to evaluate the accuracy and precision of pulse contour analysis (PCA) compared with cardiac magnetic resonance imaging (CMR). DESIGN: A single-center prospective study. SETTING: A university hospital. PARTICIPANTS: Thirty-nine consecutive stable patients undergoing CMR. INTERVENTIONS: CO was determined twice by PCA using the Nexfin monitoring system (BMEYE BV, Amsterdam, The Netherlands). Measurements were performed after 10 minutes of rest in a stable supine position immediately before or after the CMR examination. MEASUREMENTS AND MAIN RESULTS: There was a mean bias of 0.2 ± 1.9 L/min between CMR and PCA and a reproducibility of 0.2 ± 0.6 L/min for PCA. Between 4.8 and 6.3 L/min (second quartile of CO(CMR)), there was a good agreement (mean bias = -0.2 ± 1.3 L/min). Comparing quartile 1 (-1.3 ± 2.0 L/min) overestimating and quartiles 3 (1.4 ± 0.9 L/min) and 4 (0.9 ± 2.0 L/min) underestimating CO, a statistically significant difference was found. The reproducibility was not affected by the quartile (p = 0.23, analysis of variance), whereas there was a significant difference between the nonoutlier and outlier group when using the Mann-Whitney U test (p = 0.02). CONCLUSIONS: Noninvasive PCA allows the safe and economic measurement of CO, yet it still has major limitations. Although the agreement with CMR was acceptable, there was a clinically unacceptable variation; absolute values should not be used interchangeably. These results suggest that therapeutic interventions and clinical decisions should not be based on noninvasive PCA measurements at the present time.
  Journal of cardiothoracic and vascular anesthesia 10/2012; · 1.06 Impact Factor
• Article: Alterations of leptin in the course of inflammation and severe sepsis.

  Michael Behnes, Martina Brueckmann, Siegfried Lang, Christian Putensen, Joachim Saur, Martin Borggrefe, Ursula Hoffmann
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  ABSTRACT: The adipokine leptin regulates energy expenditure, vascular function, bone and cartilage growth as well as the immune system and systemic inflammatory response. Several activating effects towards T cells, monocytes, endothelium cells and cytokine production have been reported suggesting a protective role of leptin in the setting of an acute systemic inflammation. However, the pathophysiological role of leptin during severe sepsis is currently not elucidated in detail. This study aims to investigate leptin expression in cultured human adipocytes within an inflammatory model and in patients suffering from severe sepsis and evaluates treatment effects of drotrecogin alpha (activated) (DAA), the recombinant form of human activated protein C. In an in-vitro inflammatory model of adipocyte cell-culture the effect of DAA on leptin mRNA expression was evaluated. Synthesis of mRNA was measured by quantitative polymerase chain reaction (qPCR). Additionally, supernatants of these adipocytes as well as serum levels of adiponectin were measured in blood of 104 severe septic patients by ELISA-method. 26 patients were treated with DAA (DAA+), 78 patients were not treated with DAA (DAA-). Stimulation of human adipocytes with TNF alpha over 6 and 24 hours resulted in a significant decrease by 46% and 59% of leptin mRNA transcripts compared to un-stimulated controls (p < 0.05). Leptin levels of supernatants of adipocyte culture decreased by 25% and 23% (p < 0.05) after incubation with TNF alpha after 6 and 24 hours. Incubation with DAA at 50 ng/ml DAA and 5 μg/ml doubled mRNA expression significantly at 24 hours (p < 0.05) but not at 6 hours. From day 1 to day 3 of sepsis, leptin levels increased in DAA+ compared to DAA- patients (p<0.10). Leptin appears to be involved in the pathogenesis of a systemic inflammatory response during sepsis. Administration of DAA significantly increased leptin expression. The specific mechanism or even benefit of DAA towards leptin needs further ongoing research.
  BMC Infectious Diseases 09/2012; 12:217. · 3.12 Impact Factor
• Article: Coronary computed tomography and triple rule out CT in patients with acute chest pain and an intermediate cardiac risk profile. Part 1: Impact on patient management.

  Joachim Gruettner, Christian Fink, Thomas Walter, Mathias Meyer, Paul Apfaltrer, U Joseph Schoepf, Joachim Saur, Tim Sueselbeck, Dominik Traunwieser, Richard Takx, Stefan Kralev, Martin Borggrefe, Stefan O Schoenberg, Thomas Henzler
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  ABSTRACT: OBJECTIVE: To evaluate the impact of coronary CT angiography (coronary CTA) or "triple-rule-out" CT angiography (TRO-CTA) on patient management in the work-up of patients with acute chest pain and an intermediate cardiac risk profile. MATERIALS AND METHODS: 100 patients with acute chest pain and an intermediate cardiac risk for acute coronary syndrome (ACS) underwent coronary CTA or TRO-CTA for the evaluation of chest pain. Patients with a high and low cardiac risk profile were not included in this study. All patients with significant coronary stenosis >50% on coronary CTA underwent invasive coronary catheterization (ICC). Important other pathological findings were recorded. All patients had a 90-day follow-up period for major adverse cardiac events (MACE). RESULTS: Based on a negative coronary CTA 60 of 100 patients were discharged on the same day. None of the discharged patients showed MACE during the 90-day follow-up. Coronary CTA revealed a coronary stenosis >50% in 19 of 100 patients. ICC confirmed significant coronary stenosis in 17/19 patients. Among the 17 true positive patients, 9 underwent percutaneous coronary intervention with stent implantation, 7 were received intensified medical therapy, and 1 patient underwent coronary artery bypass surgery. A TRO-CTA protocol was performed in 36/100 patients due to elevated d-dimer levels. Pulmonary embolism was present in 5 patients, pleural effusion of unknown etiology in 3 patients, severe right ventricular dysfunction with pericardial effusion in 1 patient, and an incidental bronchial carcinoma was diagnosed in 1 patient. CONCLUSION: Coronary CTA and TRO-CTA allow a rapid and safe discharge in the majority of patients presenting with acute chest pain and an intermediate risk for ACS while at the same time identifies those with significant coronary artery stenosis.
  European journal of radiology 06/2012; · 2.65 Impact Factor
• Article: Alterations of adiponectin in the course of inflammation and severe sepsis.

  Michael Behnes, Martina Brueckmann, Siegfried Lang, Christian Putensen, Joachim Saur, Martin Borggrefe, Ursula Hoffmann
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  ABSTRACT: The adipocyte-specific protein adiponectin reveals anti-inflammatory, antioxidant, antiatherosclerotic and vasoprotective effects. This study aims to investigate adiponectin expression in cultured human adipocytes within an inflammatory model and in patients with severe sepsis and evaluates treatment effects of drotrecogin α (activated) (DAA). In an in vitro inflammatory model of adipocyte cell culture, the effect of DAA on adiponectin mRNA expression was evaluated. Synthesis of mRNA was measured by quantitative polymerase chain reaction. Supernatants of these adipocytes and serum levels of adiponectin were measured in blood of 104 patients by enzyme-linked immunosorbent assay on days 1, 3, and 5 of severe sepsis. Twenty-six patients were treated with DAA (DAA), 78 patients without DAA (DAA). Stimulation of human adipocytes with tumor necrosis factor α over 6 and 24 h resulted in a significant decrease in adiponectin mRNA transcripts. After 24 h of incubation, adiponectin mRNA expression was significantly upregulated according to applied dosages of DAA at 50 ng/mL and 5 μg/mL (P < 0.05). Accordingly, adiponectin levels of supernatants of adipocyte culture increased after 24 h (P < 0.05). DAA patients revealed significantly higher adiponectin serum levels compared with healthy controls (P < 0.1) and DAA patients (P < 0.05) at days 1 and 3. On day 5 after 96-h infusion of DAA (24 μg/kg per hour), adiponectin levels significantly increased in DAA patients and equalized toward DAA patients (P > 0.1). Adiponectin might be involved in the pathogenesis of the systemic inflammatory response during sepsis. Administration of DAA upregulates adiponectin expression under circumstances of systemic inflammation.
  Shock (Augusta, Ga.) 06/2012; 38(3):243-8. · 2.87 Impact Factor
• Article: Monitoring treatment response in precapillary pulmonary hypertension using non-invasive haemodynamic measurements.

  Frederik Trinkmann, Dariusch Haghi, Joachim Saur
  Thorax 09/2011; 67(1):81; author reply 81-2. · 6.84 Impact Factor
• Article: A comparative evaluation of electrical velocimetry and inert gas rebreathing for the non-invasive assessment of cardiac output.

  Frederik Trinkmann, Manuel Berger, Ursula Hoffmann, Martin Borggrefe, Jens J Kaden, Joachim Saur
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  ABSTRACT: When assessing the function of the cardiovascular system, cardiac output (CO) is a substantial parameter. For its determination, numerous non-invasive techniques have been proposed in the recent years including inert gas rebreathing (IGR) and impedance cardiography (ICG). The aim of our study was to evaluate whether a novel ICG algorithm (electrical velocimetry) and IGR can be used interchangeably in the clinical setting. A total of 120 consecutive stable patients were included resulting in two pairs of repeated non-invasive cardiac output measurements. The mean CO was 5.0 ± 1.2 l/min (range 2.6-8.6 l/min) using IGR and 4.4 ± 1.1 l/min (1.7-7.4 l/min) using ICG, respectively. Bland-Altman analysis revealed an acceptable agreement with a mean bias of 0.6 ± 1.2 l/min. We found a high reproducibility with a mean bias of 0.2 ± 0.7 l/min for IGR and 0.0 ± 0.3 l/min for ICG (p < 0.001), respectively. There was a statistically significant difference for unphysiological circulatory conditions represented by values of 2.6-4.1 l/min and 5.6-8.6 l/min. Both non-invasive techniques are associated with low operating costs and require only a few expendable items for the rapid determination of cardiac function. We found an acceptable agreement between IGR and ICG as well as a high reproducibility, which was statistically significant higher for ICG. For cardiac output states exceeding the physiological range, we found a statistically significant difference. Consequently, values of cardiac function determined by either method should not be used interchangeably in the clinical setting.
  Clinical Research in Cardiology 07/2011; 100(10):935-43. · 2.95 Impact Factor
• Article: The impact of pulmonary disease on noninvasive measurement of cardiac output by the inert gas rebreathing method.

  Joachim Saur, Frederik Trinkmann, Christina Doesch, Armin Scherhag, Joachim Brade, Stefan O Schoenberg, Martin Borggrefe, Jens J Kaden, Theano Papavassiliu
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  ABSTRACT: Cardiac output (CO) is an important parameter for diagnosis and therapy of heart diseases, but it is still difficult to determine. Innocor, a novel noninvasive inert gas rebreathing (IGR) system, has shown promising results. However, the impact of pulmonary diseases on IGR remains unclear. The aim of the study therefore was to assess the accuracy and reliability of IGR in patients with distinct chronic lung disease. A total of 96 patients were enrolled, including 48 consecutive patients with variant lung diseases (group A) and 48 pair-matched pulmonary healthy patients (group B). CO was measured with cardiac magnetic resonance imaging (CMR) and IGR. Lung function testing was done by spirometry [FEV(1)/FVC (forced expiratory volume in one second/forced vital capacity), VC (vital capacity)] and determination of the diffusing capacity of the lung for carbon monoxide divided by alveolar volume (DLCO/VA). In group A we found a mean CO of 4.7 ± 1.3 L/min by IGR and 4.9 ± 1.2 L/min by CMR. Group B showed a mean CO of 4.8 ± 1.4 L/min by IGR and 5.0 ± 1.3 L/min by CMR. Bland-Altman analysis revealed good correspondence between CMR and IGR, with an average deviation of 0.1 ± 1.0 L/min in group A and 0.1 ± 1.0 L/min in group B (p = 0.99). Multiple regression analysis for the pulmonary parameters did not show a statistically significant impact on the mean bias of CO measurements (FEV(1)/FVC: r = 0.01, p = 0.91; VC: r = -0.2, p = 0.13; and DLCO/VA: r = 0.04, p = 0.82). IGR allows a feasible determination of CO even in patients with lung diseases. The accuracy of the IGR method is not influenced by either pulmonary obstructive and restrictive diseases or a reduced DLCO.
  Beiträge zur Klinik der Tuberkulose 10/2010; 188(5):433-40. · 1.90 Impact Factor
• Article: A novel noninvasive ultrasonic cardiac output monitor: comparison with cardiac magnetic resonance.

  Frederik Trinkmann, Christina Doesch, Theano Papavassiliu, Joerg Weissmann, Dariusch Haghi, Joachim Gruettner, Stefan O Schoenberg, Martin Borggrefe, Jens J Kaden, Joachim Saur
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  ABSTRACT: USCOM, a novel continuous wave Doppler (CWD) device, has been introduced for noninvasive determination of cardiac output (CO). The present study aimed to compare the accuracy and reproducibility of the new device, using cardiovascular magnetic resonance imaging (CMR) as the noninvasive gold standard. The CO of 56 consecutive patients was prospectively determined by CWD either before or after CMR imaging. The CWD probe was placed in the suprasternal or supraclavicular notch aiming at the aortic valve. Valid CWD signals could be obtained in 45 patients yielding a CO of 5.3+/-1.1 L/min (range, 3.0-7.5 L/min) by CMR and 4.7+/-1.1 L/min by CWD (2.5-8.0 L/min, P = .004), respectively. CWD measurements showed an acceptable agreement with CMR (bias: 0.6+/-1.1 L/min) and a high reproducibility (bias: 0.1+/-0.4 L/min). Higher CO and body mass index (BMI) were identified as sources of inaccuracy in univariate analysis. By multivariate analysis, only CO(CMR) was found to be independently associated with larger variation. Estimated diameters of the left ventricular outflow tract (LVOT), a prerequisite for CO measurement by CWD, correlated only weakly with those measured by CMR. Continuous wave Doppler is a feasible technique for measuring cardiac function. Although the overall agreement with CMR was acceptable, CWD showed a trend to underestimate CO. The estimated LVOT diameter by CWD is likely to be an important source of error. Nevertheless, the CWD device could be of clinical use especially for detection of intraindividual hemodynamic changes since a high reproducibility could be demonstrated.
  Clinical Cardiology 02/2010; 33(2):E8-14. · 2.15 Impact Factor
• Article: Noninvasive determination of cardiac output by the inert-gas-rebreathing method--comparison with cardiovascular magnetic resonance imaging.

  Joachim Saur, Stephan Fluechter, Frederik Trinkmann, Theano Papavassiliu, Stefan Schoenberg, Joerg Weissmann, Dariusch Haghi, Martin Borggrefe, Jens J Kaden
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  ABSTRACT: An easy, noninvasive and accurate technique for measuring cardiac output (CO) would be desirable for the diagnosis and therapy of cardiac diseases. Innocor, a novel inert-gas-rebreathing (IGR) system, has shown promising results in smaller studies. An extensive evaluation in a larger, less homogeneous patient collective is lacking. We prospectively assessed the accuracy and reproducibility of CO measurements obtained by IGR in 305 consecutive patients as compared to the noninvasive gold standard, cardiovascular magnetic resonance (CMR) imaging. Bland-Altman analysis showed a good correspondence of the two methods for CO measurement with an average deviation of 0.2 +/- 1.0 liters/min (mean +/- SD) and a good reproducibility with a mean bias of 0.2 +/- 0.5 liters/min. The accuracy of the present measurements at rest was significantly better in the physiological range than in higher or lower CO ranges. The error levels set forth by current recommendations were exceeded. The data show that IGR measurements are easy to perform and show good agreement with CMR; however, the technique appears to be less accurate in extreme CO ranges at rest. The clinical importance of the IGR method remains to be proven by further studies.
  Cardiology 09/2009; 114(4):247-54. · 1.71 Impact Factor
• Article: Non-invasive determination of cardiac output: comparison of a novel CW Doppler ultrasonic technique and inert gas rebreathing.

  Joachim Saur, Frederik Trinkmann, Jörg Weissmann, Martin Borggrefe, Jens J Kaden
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  ABSTRACT: Cardiac Output (CO) is an important parameter in the diagnosis and therapy of heart diseases. Inert gas rebreathing (IGR) and continuous wave Doppler ultrasound (CWD) are among the most promising newer techniques aiming at a non-invasive, point of care measurement of CO. A direct comparison of the two methods has not yet been carried out. 63 consecutive patients were included in the study. CO was measured twice with both CWD and IGR to assess inter-method agreement and reproducibility. The statistical comparisons were performed as proposed by Bland and Altman. There was a significant correlation between the CO measurements by both methods (r=0.53, p<0.001). Bland-Altman analysis showed a good agreement of measurements with a bias of 0.4+/-1.0 l/min (mean+/-standard deviation). Both methods showed a good reproducibility. CWD measurements were not possible in 14% of patients while IGR measurements were not possible in 5% of patients (p=0.13). The determination of CO by IGR and CWD revealed a good agreement and reproducibility with a low rate of impossible measurements, suggesting that IGR and CWD can be used interchangeably in the clinical setting.
  International journal of cardiology 08/2009; 136(2):248-50. · 7.08 Impact Factor
• Article: Non-invasive determination of cardiac output by the inert gas rebreathing method in a patient with an axial-flow left-ventricular assist device.

  Joachim Saur, Frederik Trinkmann, Ursula Hoffmann, Jens J Kaden, Dariusch Haghi
  The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 06/2009; 28(5):533-4. · 3.54 Impact Factor
• Article: Aortic regurgitation during left ventricular assist device support.

  Dariusch Haghi, Tim Suselbeck, Joachim Saur
  The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 12/2007; 26(11):1220-1. · 3.54 Impact Factor
• Article: Takotsubo cardiomyopathy (acute left ventricular apical ballooning syndrome) occurring in the intensive care unit.

  Dariusch Haghi, Stephan Fluechter, Tim Suselbeck, Joachim Saur, Osama Bheleel, Martin Borggrefe, Theano Papavassiliu
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  ABSTRACT: Diagnosis of Takotsubo cardiomyopathy (also known as stress cardiomyopathy or acute left ventricular apical ballooning syndrome) can be challenging in patients who are being treated for other diseases in the intensive care unit, because symptoms could erroneously be attributed to the underlying disease or patients may not experience symptoms due to analgesia and sedation. The aim of our study was to assess clinical features of Takotsubo cardiomyopathy occurring in the intensive care unit. Prospective observational study. University hospital. Six consecutive patients diagnosed with Takotsubo cardiomyopathy who were being treated for other diseases in the intensive care unit. None. Sudden hemodynamic deterioration (i.e., sudden hypotension, tachycardia or drop in monitored stroke volume) requiring vasopressor support was the presenting symptom in five of the six patients. Only one patient was able to report angina-like chest pain, all others were unable to experience symptoms due to analgesia and sedation. The electrocardiogram was abnormal in all patients upon diagnosis, demonstrating either ST-segment elevation (n=2) and/or T-wave inversion (n=5). Mild elevation of cardiac enzymes disproportionate to the extent of wall motion abnormalities on left ventriculography was present in all patients. All patients survived their acute event. Sudden hemodynamic deterioration requiring vasopressor support and/or ECG abnormalities consisting of ST-segment elevation, ST-segment depression or T-wave inversion may be the presenting symptom of Takotsubo cardiomyopathy in the intensive care unit and should be included in the diagnostic algorithm.
  Intensive Care Medicine 08/2006; 32(7):1069-74. · 5.40 Impact Factor
• Source

  Available from: Hans Leweling

  Article: Modification of the Harris-Benedict equation to predict the energy requirements of critically ill patients during mild therapeutic hypothermia.

  Joachim Saur, Hans Leweling, Frederik Trinkmann, Joerg Weissmann, Martin Borggrefe, Jens J Kaden
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  ABSTRACT: The aim of the present study was the comparison of calculated and measured values of the energy expenditure of critically ill patients during the different phases of therapeutic mild hypothermia. Five patients (mean age 40.6 years, range 23 to 68 years, 2 females) suffering from severe acute cerebral injuries who underwent mild hypothermia were prospectively included into the study. Indirect calorimetry measurements were made at intervals of 3-4 hours and subsequently, during the steady state, at least every 12 hours. The results were compared with the basal metabolic rate calculated by the Harris-Benedict equation. A close linear correlation between body temperature and basal metabolism could be observed across a wide range of temperatures from 30.5 degrees C to 38.3 degrees C (r=0.82, p<0.001). One degree drop in temperature led to a 5.9% reduction in energy. During mild hypothermia, oxygen consumption was reduced by 71 mL/min (95% confidence interval 57 to 86 mL/min; p<0.001) as compared to base line. The basal metabolism rate was decreased by 30.3% (95% confidence interval 24.7 to 35.9%, p<0.001). The average value recorded was 16.7% below the values calculated in accordance with the Harris-Benedict equation (95% confidence interval 12.8 to 20.6%). The immediate reduction in oxygen requirements achieved by hypothermia is linearly correlated with the reduction in temperature and the hypothermia induced reduction in oxygen requirement recorded by indirect calorimetry is considerably below that calculated in accordance with the Harris-Benedict equation. If indirect calorimetry should not be available and the Harris-Benedict equation is used, a corrective factor is therefore needed to avoid an inaccurate calorie administration.
  In vivo (Athens, Greece) 22(1):143-6. · 1.17 Impact Factor