Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Marc Dorenkamp is active.

Publication


Featured researches published by Marc Dorenkamp.


European Journal of Echocardiography | 2015

Normal values and clinical relevance of left atrial myocardial function analysed by speckle-tracking echocardiography: multicentre study

Daniel A. Morris; Masaaki Takeuchi; Maximilian Krisper; Clemens Köhncke; Tarek Bekfani; Tim Carstensen; Sabine Hassfeld; Marc Dorenkamp; Kyoko Otani; Kiyohiro Takigiku; Chisato Izumi; Satoshi Yuda; Konomi Sakata; Nobuyuki Ohte; Kazuaki Tanabe; Engin Osmanoglou; York Kühnle; Hans-Dirk Düngen; Satoshi Nakatani; Yutaka Otsuji; Wilhelm Haverkamp; Leif-Hendrik Boldt

AIMS The aim of this multicentre study was to determine the normal range and the clinical relevance of the myocardial function of the left atrium (LA) analysed by 2D speckle-tracking echocardiography (2DSTE). METHODS AND RESULTS We analysed 329 healthy adult subjects prospectively included in 10 centres and a validation group of 377 patients with left ventricular diastolic dysfunction (LVDD). LA myocardial function was analysed by LA strain rate peak during LA contraction (LA-SRa) and LA strain peak during LA relaxation (LA-Strain). The range of values of LA myocardial function in healthy subjects was LA-SRa -2.11 ± 0.61 s(-1) and LA-Strain 45.5 ± 11.4%, and the lowest expected values of these LA analyses (calculated as -1.96 SD from the mean of healthy subjects) were LA-SRa -0.91 s(-1) and LA-Strain 23.1%. Concerning the clinical relevance of these LA myocardial analyses, LA-SRa and LA-Strain detected subtle LA dysfunction in patients with LVDD, even though LA volumetric measurements were normal. In addition, in these patients we found that the functional class (dyspnoea-NYHA classification) was inversely related to both LA-Strain and LA-SRa. CONCLUSION In the present multicentre study analysing a large cohort of healthy subjects and patients with LVDD, the normal range and the clinical relevance of the myocardial function of the LA using 2DSTE have been determined.


European Heart Journal | 2013

Potential lifetime cost-effectiveness of catheter-based renal sympathetic denervation in patients with resistant hypertension

Marc Dorenkamp; Klaus Bonaventura; Alexander Leber; Julia Boldt; Christian Sohns; Leif-Hendrik Boldt; Wilhelm Haverkamp; Ulrich Frei; Mattias Roser

AIMS Recent studies have demonstrated the safety and efficacy of catheter-based renal sympathetic denervation (RDN) for the treatment of resistant hypertension. We aimed to determine the cost-effectiveness of this approach separately for men and women of different ages. METHODS AND RESULTS A Markov state-transition model accounting for costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness was developed to compare RDN with best medical therapy (BMT) in patients with resistant hypertension. The model ran from age 30 to 100 years or death, with a cycle length of 1 year. The efficacy of RDN was modelled as a reduction in the risk of hypertension-related disease events and death. Analyses were conducted from a payers perspective. Costs and QALYs were discounted at 3% annually. Both deterministic and probabilistic sensitivity analyses were performed. When compared with BMT, RDN gained 0.98 QALYs in men and 0.88 QALYs in women 60 years of age at an additional cost of €2589 and €2044, respectively. As the incremental cost-effectiveness ratios increased with patient age, RDN consistently yielded more QALYs at lower costs in lower age groups. Considering a willingness-to-pay threshold of €35 000/QALY, there was a 95% probability that RDN would remain cost-effective up to an age of 78 and 76 years in men and women, respectively. Cost-effectiveness was influenced mostly by the magnitude of effect of RDN on systolic blood pressure, the rate of RDN non-responders, and the procedure costs of RDN. CONCLUSION Renal sympathetic denervation is a cost-effective intervention for patients with resistant hypertension. Earlier treatment produces better cost-effectiveness ratios.


European Journal of Echocardiography | 2013

Left atrial volumetry from routine diagnostic work up prior to pulmonary vein ablation is a good predictor of freedom from atrial fibrillation

Christian Sohns; Jan M Sohns; Dirk Vollmann; Lars Lüthje; Leonard Bergau; Marc Dorenkamp; Pa Zwaka; Gerd Hasenfuß; Joachim Lotz; Markus Zabel

AIMS This study aimed to identify whether left atrial (LA) volume assessed by multidetector computed tomography (MDCT) is related to the long-term success of pulmonary vein ablation (PVA). MDCT is used to guide PVA for the treatment of atrial fibrillation (AF). MDCT permits accurate sizing of LA dimensions. METHODS AND RESULTS We analysed data from 368 ablation procedures of 279 consecutive patients referred for PVA due to drug-refractory symptomatic AF (age 62 ± 10; 58% men; 71% paroxysmal AF). Prior to the procedure, all patients underwent ECG-gated 64-MDCT scan for assessment of LA and PV anatomy, LA thrombus evaluation, LA volume estimation, and electroanatomical mapping integration. Within a mean follow-up of 356 ± 128 days, 64% of the patients maintained sinus rhythm after the initial ablation, and 84% when including repeat PVA. LA diameter (P = 0.004), LA volume (P = 0.002), and type of AF (P = 0.001) were independent predictors of AF recurrence in univariate analysis. There was a relatively low correlation between the echocardiographic LA diameter and LA volume from MDCT (P = 0.01, r = 0.5). In multivariate analysis, paroxysmal AF (P < 0.006) and LA volume below the median value of 106 mL (P = 0.042) were significantly associated with the success of PVA, whereas LA diameter was not (P = 0.245). Analysing receiver-operator characteristics, the area under the curve for LA volume was 0.73 (P = 0.001) compared with 0.60 (P = 0.09) for LA diameter from echocardiography. CONCLUSION LA volume assessed by MDCT is a better predictor of AF recurrence after PVA than echocardiograpic LA diameter and can be derived from the pre-procedural imaging data set.


Journal of Cardiovascular Magnetic Resonance | 2013

Cost-effectiveness of cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary artery disease in Germany

Julia Boldt; Alexander Leber; Klaus Bonaventura; Christian Sohns; Martin Stula; Alexander Huppertz; Wilhelm Haverkamp; Marc Dorenkamp

BackgroundRecent studies have demonstrated a superior diagnostic accuracy of cardiovascular magnetic resonance (CMR) for the detection of coronary artery disease (CAD). We aimed to determine the comparative cost-effectiveness of CMR versus single-photon emission computed tomography (SPECT).MethodsBased on Bayes’ theorem, a mathematical model was developed to compare the cost-effectiveness and utility of CMR with SPECT in patients with suspected CAD. Invasive coronary angiography served as the standard of reference. Effectiveness was defined as the accurate detection of CAD, and utility as the number of quality-adjusted life-years (QALYs) gained. Model input parameters were derived from the literature, and the cost analysis was conducted from a German health care payer’s perspective. Extensive sensitivity analyses were performed.ResultsReimbursement fees represented only a minor fraction of the total costs incurred by a diagnostic strategy. Increases in the prevalence of CAD were generally associated with improved cost-effectiveness and decreased costs per utility unit (ΔQALY). By comparison, CMR was consistently more cost-effective than SPECT, and showed lower costs per QALY gained. Given a CAD prevalence of 0.50, CMR was associated with total costs of €6,120 for one patient correctly diagnosed as having CAD and with €2,246 per ΔQALY gained versus €7,065 and €2,931 for SPECT, respectively. Above a threshold value of CAD prevalence of 0.60, proceeding directly to invasive angiography was the most cost-effective approach.ConclusionsIn patients with low to intermediate CAD probabilities, CMR is more cost-effective than SPECT. Moreover, lower costs per utility unit indicate a superior clinical utility of CMR.


Journal of Hypertension | 2014

Potential cost-effectiveness of therapeutic drug monitoring in patients with resistant hypertension.

Oliver Chung; Wanpen Vongpatanasin; Klaus Bonaventura; Yair Lotan; Christian Sohns; Wilhelm Haverkamp; Marc Dorenkamp

Background: Nonadherence to drug therapy poses a significant problem in the treatment of patients with presumed resistant hypertension. It has been shown that therapeutic drug monitoring (TDM) is a useful tool for detecting nonadherence and identifying barriers to treatment adherence, leading to effective blood pressure (BP) control. However, the cost-effectiveness of TDM in the management of resistant hypertension has not been investigated. Method: A Markov model was used to evaluate life-years, quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios in resistant hypertension patients receiving either TDM optimized therapy or standard best medical therapy. The model ran from the age of 30 to 100 years or death, using a cycle length of 1 year. Efficacy of TDM was modeled by reducing risk of hypertension-related morbidity and mortality. Cost analyses were performed from a payers perspective. Deterministic and probabilistic sensitivity analyses were conducted. Results: In the age group of 60-year olds, TDM gained 1.07 QALYs in men and 0.97 QALYs in women at additional costs of &OV0556;3854 and &OV0556;3922, respectively. Given a willingness-to-pay threshold of &OV0556;35 000 per QALY gained, the probability of TDM being cost-effective was 95% or more in all age groups from 30 to 90 years. Results were influenced mostly by the frequency of TDM testing, the rate of nonresponders to TDM, and the magnitude of effect of TDM on BP. Conclusion: Therapeutic drug monitoring presents a potential cost-effective healthcare intervention in patients diagnosed with resistant hypertension. Importantly, this finding is valid for a wide range of patients, independent of sex and age.


Europace | 2013

Pulmonary vein anatomy predicts freedom from atrial fibrillation using remote magnetic navigation for circumferential pulmonary vein ablation

Christian Sohns; Jan M Sohns; Leonard Bergau; Samuel Sossalla; Dirk Vollmann; Lars Lüthje; Wieland Staab; Marc Dorenkamp; James Harrison; Mark O'Neill; Joachim Lotz; Markus Zabel

AIMS Multidetector computed tomography (MDCT) is frequently used to guide circumferential pulmonary vein ablation (PVA) for treatment of atrial fibrillation (AF) as it offers accurate visualization of the left atrial (LA) and pulmonary vein (PV) anatomy. This study aimed to identify if PV anatomy is associated with outcomes following PVA using remote magnetic navigation (RMN). METHODS AND RESULTS We analysed data from 138 consecutive patients and 146 ablation procedures referred for PVA due to drug-refractory symptomatic AF (age 63 ± 11 years; 57% men; 69% paroxysmal AF). The RMN using the stereotaxis system and open-irrigated 3.5 mm ablation catheters was used in all procedures. Prior to PVA, all patients underwent electrocardiogram-gated 64-MDCT for assessment of LA dimensions, PV anatomy, and electro-anatomical image integration during the procedure. Regular PV anatomy was found in 68%, a common left PV ostium was detected in 26%, and variant anatomy of the right PVs was detected in 6%. After a mean follow-up of 337 ± 102 days, 63% of the patients maintained sinus rhythm after the initial ablation, and 83% when including repeat PVA. Although acutely successful PV isolation did not differ between anatomical subgroups (regular 3.5 ± 0.8 vs. variant 3.2 ± 1.3; P = 0.31), AF recurrence was significantly higher in patients with non-regular PV anatomy (P = 0.04, hazard ratio 1.72). Pulmonary vein anatomy did not influence complication rates. CONCLUSION Pulmonary vein anatomy assessed by MDCT is a good predictor of AF recurrence after PVA using RMN.


Clinical Cardiology | 2013

Cost-Effectiveness of Paclitaxel-Coated Balloon Angioplasty in Patients With Drug-Eluting Stent Restenosis

Marc Dorenkamp; Julia Boldt; Alexander Leber; Christian Sohns; Mattias Roser; Leif-Hendrik Boldt; Wilhelm Haverkamp; Klaus Bonaventura

The economic impact of drug‐eluting stent (DES) in‐stent restenosis (ISR) is substantial, highlighting the need for cost‐effective treatment strategies.


Journal of Cardiovascular Pharmacology and Therapeutics | 2007

Role of Coronary Angiography Before Radiofrequency Ablation in Patients Presenting With Paroxysmal Supraventricular Tachycardia

Marc Dorenkamp; Markus Zabel; Christian Sticherling

During episodes of paroxysmal supraventricular tachycardia (PSVT), electrocardiograms frequently show ST-segment depressions, and patients may experience typical chest pain prompting invasive coronary angiography. We evaluated 114 patients presenting with PSVT for concomitant coronary artery disease (CAD). Patients were classified as to the type of PSVT, symptoms during PSVT, and cardiovascular risk factors. Maximum heart rate, extent of ST-segment depression, and cardiac troponin levels during PSVT were recorded. Patients were subjected to exercise testing and/or coronary angiography. During PSVT, symptoms suggestive of myocardial ischemia, including chest pain (31%), ST-segment depression (61%), and elevated troponin levels (12%), were common. Sixty-seven patients (59%) underwent coronary angiography. The overall prevalence of significant CAD was found to be low (4%) and did not correlate to symptoms during tachycardia. Routine coronary angiography cannot be recommended in patients with PSVT unless routine evaluation outside episodes of tachycardia suggests the presence of significant CAD.


Europace | 2016

Sex difference in appropriate shocks but not mortality during long-term follow-up in patients with implantable cardioverter-defibrillators

Joachim Seegers; David Conen; Klaus Jung; Leonard Bergau; Marc Dorenkamp; Lars Lüthje; Christian Sohns; Samuel Sossalla; Thomas H. Fischer; Gerd Hasenfuss; Tim Friede; Markus Zabel

Abstract Aims Implantable cardioverter-defibrillators (ICDs) have been shown to improve survival, although a considerable number of patients never receive therapy. Implantable cardioverter-defibrillators are routinely implanted regardless of sex. There is continuing controversy whether major outcomes differ between men and women. Methods and results In this retrospective single-centre study, 1151 consecutive patients (19% women) undergoing ICD implantation between 1998 and 2010 were followed for mortality and first appropriate ICD shock over 4.9 ± 2.7 years. Sex-related differences were investigated using multivariable Cox models adjusting for potential confounders. During follow-up, 318 patients died, a rate of 5.9% per year among men and 4.6% among women (uncorrected P = 0.08); 266 patients received a first appropriate ICD shock (6.3% per year among men vs. 3.6% among women, P = 0.002). After multivariate correction, independent predictors of all-cause mortality were age (hazard ratio, HR = 1.04 per year of age, 95% confidence interval (CI) [1.03–1.06], P < 0.001), left ventricular ejection fraction (HR = 0.98 per %, 95% CI [0.97–1.00], P = 0.025), renal function (HR = 0.99 per mL/min/1.73 m2, 95% CI [0.99–1.00], P = 0.009), use of diuretics (HR = 1.81, 95% CI [1.29–2.54], P = 0.0023), peripheral arterial disease (HR = 2.21, 95% CI [1.62–3.00], P < 0.001), and chronic obstructive pulmonary disease (HR = 1.48, 95% CI [1.13–1.94], P = 0.029), but not sex. Female sex (HR = 0.51, 95% CI [0.33–0.81], P = 0.013), older age (HR = 0.98, 95% CI [0.97–0.99], P < 0.001), and primary prophylactic ICD indication (HR = 0.69, 95% CI [0.52–0.93], P = 0.043) were independent predictors for less appropriate shocks. Conclusion Women receive 50% less appropriate shocks than men having similar mortality in this large single-centre population. These data may pertain to individually improved selection of defibrillator candidates using risk factors, e.g. sex as demonstrated in this study.


Journal of Magnetic Resonance Imaging | 2014

Vascular and extravascular findings on magnetic resonance angiography of the thoracic aorta and the origin of the great vessels

Jan M Sohns; Wieland Staab; Jan Menke; Leonard Bergau; Darius Dabir; Alexander Schwarz; Judith Eva Spiro; Marc Dorenkamp; James Harrison; Michael Steinmetz; Joachim Lotz; Christian Sohns

To investigate the presence of relevant vascular and incidental extravascular findings in patients undergoing magnetic resonance angiography (MRA) of the thoracic aorta and origin of the great vessels.

Collaboration


Dive into the Marc Dorenkamp's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Leonard Bergau

University of Göttingen

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Joachim Lotz

University of Göttingen

View shared research outputs
Researchain Logo
Decentralizing Knowledge