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Dive into the research topics where Michael Petersen is active.

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Featured researches published by Michael Petersen.


European Journal of Cardio-Thoracic Surgery | 2014

The fate of the bicuspid valve aortopathy after aortic valve replacement.

Efstratios I. Charitos; Ulrich Stierle; Michael Petersen; Salah A. Mohamed; Thorsten Hanke; Claudia Schmidtke; Stefan Klotz; Hans-Hinrich Sievers

OBJECTIVES The fate of the aortic dimensions in patients with a bicuspid aortic valve (BAV) after aortic valve replacement (AVR) is unclear. We investigated the evolution of aortic root and ascending aorta dimensions in patients with a BAV after AVR. To neutralize the effect of pathological transvalvular haemodynamics on aortic dimensions, we evaluated our hypotheses in patients with normal transvalvular haemodynamics after a subcoronary autograft procedure, which preserves intact the native aortic wall. METHODS We excluded patients operated on for endocarditis; who developed autograft insufficiency > trivial and who required autograft reoperation during the follow-up. We included 448 patients (361 with BAV; 340 males; 44.6 ± 11.4 years; mean follow-up: 7.5 ± 3.9 years). Valve phenotype was determined during surgery. Annual echocardiographic examinations (n = 3336) were performed (follow-up completeness: 98%). To allow for somatometric, gender and age influences, z-values of measurements were calculated from the general population (GP) and analysed using longitudinal methods. RESULTS The increase in ascending aorta did not differ from that expected in the GP (0.04 z-values/year; P = 0.06). No difference could be observed in diameter increase rates between BAV and tricuspid aortic valve patients (TAV) (0.04 vs 0.06 z-values/year; P = 0.3), as well as between BAV phenotypes. The sinus increase did not differ from that expected in the GP (0.03 z-values/year; P = 0.1), and no significant differences could be observed between BAV phenotypes. In patients undergoing aortoplasty (n = 70), no significant difference in the rates of ascending aorta and sinus increase could be observed, compared with the GP. CONCLUSION For the time period of this study and in patients with normal aortic root haemodynamics after AVR, ascending aorta dimensions over time are similar to that of the matched GP. Patients with a BAV did not exhibit higher rates of ascending aorta dilatation after AVR than patients with TAV. At least for the first postoperative decade, transvalvular haemodynamics appear to exhibit a greater influence than the genetic component of BAV on the development of the BAV aortopathy.


Journal of the American College of Cardiology | 2013

Growth differentiation factor 15: a novel risk marker adjunct to the EuroSCORE for risk stratification in cardiac surgery patients.

Matthias Heringlake; Efstratios I. Charitos; Nicola Gatz; Jan-Hendrik Käbler; Anna Beilharz; Daniel Holz; Julika Schön; Hauke Paarmann; Michael Petersen; Thorsten Hanke

OBJECTIVES This study sought to determine the usefulness of plasma growth differentiation factor 15 (GDF-15) for risk stratification in patients undergoing cardiac surgery in comparison with the additive European System of Cardiac Operative Risk Evaluation (EuroSCORE), N-terminal pro-B-type natriuretic peptide (NTproBNP), and high-sensitive troponin T (hsTNT). BACKGROUND GDF-15 is emerging as a humoral marker for risk stratification in cardiovascular disease. No data are available if this marker may also be used for risk stratification in cardiac surgery. METHODS In total, 1,458 consecutive patients were prospectively studied. Pre-operative plasma GDF-15, NTproBNP, hsTNT, clinical outcomes, and 30-day and 1-year mortality were recorded. GDF-15 was determined with a pre-commercial electrochemiluminescence immunoassay. RESULTS Median additive EuroSCORE (addES) was 5 (interquartile range: 3 to 8); 30-day and 1-year mortality were 3.4% and 7.6%, respectively. Median GDF-15 levels were 1.04 ng/ml (95% confidence interval [CI]: 1.0 to 1.07 ng/ml) in 30-day survivors and 2.62 ng/ml (95% CI: 1.88 to 3.88) in 30-day nonsurvivors (p < 0.0001). C-statistics showed that the area under the curve of a combined model of GDF-15 and addES for 30-day mortality was significantly greater (0.85 vs. 0.81; p = 0.0091) than of the addES alone. For the EuroSCORE categories (0 to 2, 3 to 5, 6 to 10, >10) the presence of GDF-15 ≥1.8 ng/ml resulted in a significant 41.4% (95% CI: 19.2 to 63.7%; p < 0.001) net reclassification improvement and an integrated discrimination improvement of 0.038 (95% CI: 0.022 to 0.0547; p < 0.0001) compared to the model including only the addES, whereas the presence of NTproBNP (cutoff ≥2,000 pg/ml) or hsTNT (cutoff 14 pg/ml) did not result in significant reclassification. CONCLUSIONS The pre-operative plasma GDF-15 level is an independent predictor of post-operative mortality and morbidity in cardiac surgery patients, can further stratify beyond established risk scores and cardiovascular markers, and thus adds important additional information for risk stratification in these patients. (The Usefulness of Growth Differentiation Factor 15 [GDF-15] for Risk Stratification in Cardiac Surgery; NCT01166360).


European Journal of Cardio-Thoracic Surgery | 2013

First clinical results with the new sinus prosthesis used for valve-sparing aortic root replacement.

Claudia Schmidtke; Hans-Hinrich Sievers; Alex Frydrychowicz; Michael Petersen; Michael Scharfschwerdt; Antje Karluss; Ulrich Stierle; Doreen Richardt

OBJECTIVES Sinuses of Valsalva are important in assuring the physiological function of the aortic valve. This study evaluates short-term clinical results of the reimplantation technique for aortic valve-sparing root replacement using a new prosthesis with three separate sinuses of Valsalva (sinus prosthesis). METHODS Between February 2009 and February 2011, a total of 23 patients (20 m/3 f; mean age 52 ± 14.8 years; range 24-70 years) with aortic root aneurysm underwent aortic valve-sparing procedures according to the David reimplantation technique using the new sinus prosthesis. Eighteen patients had tricuspid and five patients bicuspid aortic valves. All patients received clinical as well as echocardiographic examinations postoperatively (mean 13 ± 9.3 months; 0.3-28 months). RESULTS There was no death and no reoperation of the aortic valve. At latest follow-up, most patients were in New York Heart Association class I (n = 22; 95.7%). In 95.7% aortic valve regurgitation (AR) was 0 or 1+; one patient had AR 2+. Pressure gradients were between the normal range (mean pressure gradient 4.7 ± 1.9 mmHg). Echocardiographic images demonstrate physiological aortic root dimensions and configuration with three separate sinuses of Valsalva without systolic contact of leaflets to the wall. CONCLUSIONS The new sinus prosthesis provides near normal root geometry and hemodynamics in valve-sparing aortic root replacement using the reimplantation technique, applicable for tricuspid and also bicuspid aortic valves.


Interactive Cardiovascular and Thoracic Surgery | 2015

Outcome with peripheral versus central cannulation in acute Type A dissection

Stefan Klotz; Kathrin Heuermann; Thorsten Hanke; Michael Petersen; Hans-Hinrich Sievers

OBJECTIVES Acute aortic dissection type A (AADA) is still an emergency operation with high morbidity and mortality. In this acute situation quick cannulation to the heart-lung machine and systemic cooling is often life-saving. However, the often easy access to the femoral vessels for cannulation leads to an arterial backflow in the descending aorta with the likelihood of plaque rupture and cerebral embolism. We analysed the outcome after initial femoral versus central cannulation for AADA. METHODS All patients with acute aortic dissection type A operated between January 2003 and December 2012 were evaluated for the type of arterial cannulation (femoral vs central) for initial bypass. Demographic data and outcome parameters were accessed. No patient was excluded. RESULTS One hundred and seventy-seven patients were operated on with acute type A dissection in the last 10 years; 94 (53.1%) were initially cannulated in the central aortic vessels and 83 (46.9%) in the femoral artery. The patients were comparable with regard to age (61.1 ± 14.9 vs 62.2 ± 15.0 years, P = 0.607), gender (male, 62 vs 69%, P = 0.348), EuroSCORE (11.5 ± 4.0 vs 12.8 ± 4.3, P = 0.057) and previous sternotomy (17% in both groups). Bypass (243 ± 105 vs 233 ± 83 min, P = 0.471), cross-clamp (160 ± 86 vs 150 ± 66 min, P = 0.381) and circulatory arrest times (47.8 ± 24.7 vs 42.5 ± 21.7 min, P = 0.130) were similar as were lowest temperatures (17.7 ± 1.8 vs 17.6 ± 1.3, P = 0.652). Postoperative cerebral infarction and 30-day mortality were comparable between the cannulation groups (13 vs 9%, P = 0.449 and 20 vs 17%, P = 0.699, central vs peripheral cannulation). Only postoperative need for dialysis was borderline significantly higher in the femoral cannulation group (28 vs 40%, P = 0.073). CONCLUSIONS This single-centre study with 177 patients could show that an acute aortic dissection type A can be operated on with central and peripheral cannulation with similar results. Risk for early mortality was driven by the preoperative clinical and haemodynamic status before operation rather than the cannulation technique.


The Journal of Thoracic and Cardiovascular Surgery | 2018

Valve performance classification in 630 subcoronary Ross patients over 22 years

Hans-Hinrich Sievers; Ulrich Stierle; Michael Petersen; Stefan Klotz; Doreen Richardt; Michael Diwoky; E. Charitos

Objective: To define the function of the “Ross valves” and its clinical meaning in a practical valve performance classification as part of the outcome analysis. Methods: From 1994 to 2017, 630 consecutive patients underwent the subcoronary Ross procedure at our institution. The valve performance classification combines hemodynamics, symptoms, and management criteria. Median follow‐up was 12.5 years (maximum 22.3 years, 7404 patient‐years, 99.4% completeness). Results: The mean age of the patients was 44.7 ± 11.9 years. Hospital deaths was 0.3% (n = 2). Twenty years after the operation survival was 73.1% (95% confidence interval [CI], 65.4%‐81.6%) and statistically not different from the age‐ and gender‐matched general population; freedom from reoperation was 85.9% (95% CI, 80.2%‐92.0%; 0.6% per patient‐year), 89.8% (95% CI, 84.3%‐95.7%) for autograft, and 91.0% (95% CI, 86.3%‐96.0%) for homograft. Preoperative annulus diameter, aortic regurgitation, annulus reinforcement, sinotubular junction reinforcement, and bicuspid aortic valve type were no significant risk factors for reoperation. At 20 years the probability of a patient being in valve performance class I to IV was 5%, 74%, 19%, and 1%, respectively. Time to reoperation was not different in bicuspid and tricuspid aortic valves; preoperative aortic stenosis tended to have better outcome of autograft function. Conclusions: These up to 22 years data show that the subcoronary Ross procedure continues to provide an excellent tissue aortic valve replacement. The suggested valve performance classification emerged as a practical concept for outcome analysis with the probability of 79% being in the favorable class I or II at 20 years.


The Journal of Thoracic and Cardiovascular Surgery | 2017

Survival and reoperation pattern after 20 years of experience with aortic valve–sparing root replacement in patients with tricuspid and bicuspid valves

Stefan Klotz; Sina Stock; Hans-Hinrich Sievers; Michael Diwoky; Michael Petersen; Ulrich Stierle; Doreen Richardt

Objective: Remodeling or reimplantation are established operative techniques of aortic valve–sparing root replacement. Long‐term follow‐up is necessary comparing tricuspid and bicuspid aortic valves. Methods: A total of 315 patients (tricuspid, n = 225, bicuspid, n = 89, quadricuspid, n = 1; remodeling, n = 101, reimplantation, n = 214) were evaluated. Mean follow‐up was 10.1 ± 5.6 and 6.4 ± 4.2 years for the remodeling and reimplantation group, respectively. Longest follow‐up was 21.9 years with 99.2% completeness. Mean age of the patients was 55.9 ± 14.3 for the remodeling group and 48.9 ± 14.5 years for the reimplantation group. Results: There was no significant difference in survival between the remodeling and reimplantation group (P = .11). Survival was comparable with the normal population in the reimplantation group (P = .33). Risk factors for late death were age, diabetes, and a greater New York Heart Association classification. Cumulative incidence of reoperation at 10 years was 5.8% for the reimplantation and 11.7% for the remodeling group (P = .65). Overall, there was no difference in the cumulative incidence of reoperation between tricuspid and bicuspid aortic valve patients (P = .13); however, a landmark analysis showed that in the second decade, the cumulative incidence of reoperation was greater in bicuspid aortic valve patients (P < .001). A total of 10 of 11 reoperated bicuspid aortic valves were degenerated. Conclusions: The remodeling and reimplantation aortic valve–sparing root replacement techniques provided excellent long‐term survival. Although the number of patients was relatively small, we provide some hints that in the second decade after the operation, especially in bicuspid aortic valve patients, the risk of reoperation may be increased, needing further evaluation.


Annals of cardiothoracic surgery | 2016

Is the outcome in acute aortic dissection type A influenced by of femoral versus central cannulation

Stefan Klotz; Bence Bucsky; Doreen Richardt; Michael Petersen; Hans H. Sievers

BACKGROUND The purpose of this study was to evaluate the single-center experience in initial femoral versus central cannulation of the extracorporeal circulation for acute aortic dissection type A (AADA). METHODS Between January 2003 and December 2015, 235 patients underwent repair of AADA. All patients were evaluated for the type of arterial cannulation (femoral vs. central) for initial bypass. Demographic data and outcome parameters were accessed. RESULTS One hundred and twenty seven (54.0%) were initially cannulated in the central aortic vessels (ascending aorta or subclavian/axillary artery) and 108 (46.0%) in the femoral artery. Patients were comparable between age (62.4±14.4 vs. 62.9±14.4 years, P=0.805), gender (male, 62.2 vs. 69.4%, P=0.152) and previous sternotomy (15.7 vs. 16.7%, P=0.861) between both cannulation groups; while EuroSCORE I (11.5±4.0 vs. 12.7±4.2, P=0.031) and ASA Score (3.5±0.81 vs. 3.8±0.57, P=0.011) were significantly higher in the femoral artery cannulation group. Bypass (249±102 vs. 240±81 min, P=0.474), X-clamp (166±85 vs. 157±67 min, P=0.418) and circulatory arrest time (51.6±28.7 vs. 48.3±21.7 min, P=0.365) were similar between the groups as were lowest temperature (18.1±2.0 vs. 18.1±2.2, P=0.775). Postoperative neurologic deficit and 30-day mortality were comparable between both cannulation groups (11.7 vs. 7.2%, P=0.449 and 20.2 vs. 16.9%, P=0.699, central vs. peripheral cannulation). Multivariate analysis revealed only EuroScore I above 13 as single preoperative predictor for mortality. CONCLUSIONS AADA can be operated with both femoral and central cannulation with similar results. Risk for early mortality was driven by the preoperative clinical and hemodynamic status before operation rather than the cannulation technique.


Archives of Physiology and Biochemistry | 2016

Collagen analysis of the ascending aortic dilatation associated with bicuspid aortic valve disease compared with tricuspid aortic valve

Alexander Navarrete Santos; Junfeng Yan; Peter Lochmann; Heike Pfeil; Michael Petersen; Andreas Simm; Hendrik Treede; Hans H. Sievers; Salah A. Mohamed

Abstract Dilatation of the ascending aorta is a common occurrence in patients with bicuspid aortic valve (BAV). The aim of the current study was to characterize collagen content in advanced glycation end products (AGEs) of dilated aortic tissue from two distinct areas, concave and convex aortic sites in patients with BAV and TAV. Collagen contents extracted from 100 mg tissue was isolated by enzymatic digestion using pepsin and the nondigested material was further digested using cyanogen bromide, insoluble collagen fraction (ICF) was extracted by hydrochloric acid hydrolysis. BAV tissue showed diminished fluorescence of the pepsin extracted fraction (PEF) compared with TAV tissue (12.4 ± 1.0% vs 32.9 ± 7.6%, p = 0.05). Patients with BAV had PEF of collagens significantly diminished in the dilated ascending aorta, especially in its convex portion, in course of aging and increment of dilated diameters. It is suggestible that BAV patients present more highly AGE-modified collagens in their ascending aorta.


Journal of Cardiothoracic and Vascular Anesthesia | 2017

Cytomegalovirus Serostatus as Predictor for Adverse Events After Cardiac Surgery: A Prospective Observational Study

Malte Ziemann; Matthias Heringlake; Philipp Lenor; David Juhl; Thorsten Hanke; Michael Petersen; Julika Schön; Hermann Heinze; Heinrich V. Groesdonk; Hauke Paarmann; Holger Hennig

OBJECTIVE To clarify whether reactivated cytomegalovirus (CMV) infections in critically ill patients lead to worse outcome or just identify more severely ill patients. If CMV has a pathogenic role, latently infected (CMV-seropositive) patients should have worse outcome than seronegative patients because only seropositive patients can experience a CMV reactivation. DESIGN Post-hoc analysis of a prospective observational study. SETTING Single university hospital. PARTICIPANTS The study comprised 983 consecutive patients scheduled for on-pump surgery. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS CMV antibodies were analyzed in preoperative plasma samples. Postoperative adverse events (reintubation, low cardiac output or reinfarction, dialysis, stroke) and 30-day and 1-year mortality were evaluated prospectively. The plasma of reintubated patients and matched control patients was tested for CMV deoxyribonucleic acid, and 618 patients were found to be seropositive for CMV (63%). Among these, the risk for reintubation was increased (10% v 4%, p = 0.001). This increase remained significant after correction for confounding factors (odds ratio 2.70, p = 0.003) and was detectable from the third postoperative day throughout the whole postoperative period. Other outcome parameters were not different. Reintubated seropositive patients were more frequently CMV deoxyribonucleic acid-positive than were matched control patients (40% v 8%, p<0.001). CONCLUSIONS CMV-seropositive patients had an increased risk of reintubation after cardiac surgery, which was associated with reactivations of their CMV infections. Additional studies should determine whether this complication may be prevented by monitoring of latently infected patients and administering antiviral treatment for reactivated CMV infections.


Thoracic and Cardiovascular Surgeon | 2015

Outcome of Mitral Valve Surgery in Patients with Chronic Mitral Regurgitation and Low Ejection Fraction: Repair or Replacement?

S. Klotz; S. Tsvelodub; Thorsten Hanke; Michael Petersen; U. Stiele; Hh Sievers

Objective: The amount of patients with functional mitral valve insufficiency and congestive heart failure with low ejection fraction (EF) is increasing. Whether mitral valve repair or replacement is superior regarding long-term outcome is this special patient group not yet clear and well studied. We analyzed the outcome data of all patients with mitral valve surgery and ejection fraction below 30%. Methods: We retrospectively analyzed data of 433 patients with chronic mitral regurgitation undergoing repair or replacement of the mitral valve either with a preoperative EF below 30% (n = 86, 19.9%) or between 30 and 50% (n = 347, 80.1%) between 2004 and 2012. Patients with endocarditis and other additional cardiac procedures except coronary artery bypass grafting (CABG) were excluded. Results: Patients with low EF were borderline significant more male (76.7 vs 66%, p = .070) but with a similar age (67.8 ± 9.4 vs 66.7 ± 11.5 years, p=.408) compared with patients with an EF of 30 to 50%. In the low EF group 79.1% of the mitral valves could reconstructed, in the EF30–50 group 66.9% (p = .036). All patients showed significant improvement in EF and reduction in MI grade measured by echocardiography and better NYHA class. These parameters were comparable between mitral valve reconstruction and replacement. CABG as an additional procedure was performed in 66.3% with low EF and 49% with moderate EF (p = .005). The figure shows the Kaplan-Meier Survival. All groups had significant different survivals, except replacement with moderate EF versus reconstruction in low EF (p = .113). Conclusion: Patients with low ejection fraction and mitral valve insufficiency have a worse long-term survival with mitral valve replacement. Reconstructive surgery should be attempted, especially in patients with low ejection fraction.

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S. Klotz

University of Münster

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Efstratios I. Charitos

Martin Luther University of Halle-Wittenberg

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