Stephen Gerfer

Dr. Stephen Gerfer

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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 June 2021 in Diabetologia
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CKChristina Kohlmorgen
Christina Kohlmorgen
Stephen GerferStephen Gerfer
Stephen Gerfer
KFKathrin Feldmann
Kathrin Feldmann
STSören Twarock
Sören Twarock
SHSonja Hartwig
Sonja Hartwig
MGMaria Grandoch
Maria Grandoch
Aims/hypothesis: People with diabetes have an increased cardiovascular risk with an accelerated development of atherosclerosis and an elevated mortality rate after myocardial infarction. Therefore, cardioprotective effects of glucose-lowering therapies are of major importance for the pharmacotherapy of individuals with type 2 diabetes. For sodium–glucose cotransporter 2 inhibitors (SGLT2is), in addition to a reduction in blood glucose, beneficial effects on atherosclerosis, obesity, renal function and blood pressure have been observed. Recent results showed a reduced risk of worsening heart failure and cardiovascular deaths under dapagliflozin treatment irrespective of the diabetic state. However, the underlying mechanisms are yet unknown. Platelets are known drivers of atherosclerosis and atherothrombosis and disturbed platelet activation has also been suggested to occur in type 2 diabetes. Therefore, the present study investigates the impact of the SGLT2i dapagliflozin on the interplay between platelets and inflammation in atherogenesis. Methods: Male, 8-week-old LDL-receptor-deficient (Ldlr−/−) mice received a high-fat, high-sucrose diabetogenic diet supplemented without (control) or with dapagliflozin (5 mg/kg body weight per day) for two time periods: 8 and 25 weeks. In a first translational approach, eight healthy volunteers received 10 mg dapagliflozin/day for 4 weeks. Results: Dapagliflozin treatment ameliorated atherosclerotic lesion development, reduced circulating platelet–leucocyte aggregates (glycoprotein [GP]Ib+CD45+: 29.40 ± 5.94 vs 17.00 ± 5.69 cells, p < 0.01; GPIb+lymphocyte antigen 6 complex, locus G+ (Ly6G): 8.00 ± 2.45 vs 4.33 ± 1.75 cells, p < 0.05) and decreased aortic macrophage infiltration (1.31 ± 0.62 vs 0.70 ± 0.58 ×103 cells/aorta, p < 0.01). Deeper analysis revealed that dapagliflozin decreased activated CD62P-positive platelets in Ldlr−/− mice fed a diabetogenic diet (3.78 ± 1.20% vs 2.83 ± 1.06%, p < 0.01) without affecting bleeding time (85.29 ± 37.27 vs 89.25 ± 16.26 s, p = 0.78). While blood glucose was only moderately affected, dapagliflozin further reduced endogenous thrombin generation (581.4 ± 194.6 nmol/l × min) × 10−9 thrombin vs 254.1 ± 106.4 (nmol/l × min) × 10−9 thrombin), thereby decreasing one of the most important platelet activators. We observed a direct inhibitory effect of dapagliflozin on isolated platelets. In addition, dapagliflozin increased HDL-cholesterol levels. Importantly, higher HDL-cholesterol levels (1.70 ± 0.58 vs 3.15 ± 1.67 mmol/l, p < 0.01) likely contribute to dapagliflozin-mediated inhibition of platelet activation and thrombin generation. Accordingly, in line with the results in mice, treatment with dapagliflozin lowered CD62P-positive platelet counts in humans after stimulation by collagen-related peptide (CRP; 88.13 ± 5.37% of platelets vs 77.59 ± 10.70%, p < 0.05) or thrombin receptor activator peptide-6 (TRAP-6; 44.23 ± 15.54% vs 28.96 ± 11.41%, p < 0.01) without affecting haemostasis. Conclusions/interpretation: We demonstrate that dapagliflozin-mediated atheroprotection in mice is driven by elevated HDL-cholesterol and ameliorated thrombin–platelet-mediated inflammation without interfering with haemostasis. This glucose-independent mechanism likely contributes to dapagliflozin’s beneficial cardiovascular risk profile. Graphical

1 October 2021 in Heart, Lung and Circulation
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Journal Article
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Ilija DjordjevicIlija Djordjevic
Ilija Djordjevic
ADAntje-Christin Deppe
Antje-Christin Deppe
ASAnton Sabashnikov
Anton Sabashnikov
EKElmar Kuhn
Elmar Kuhn
Kaveh EghbalzadehKaveh Eghbalzadeh
Kaveh Eghbalzadeh
TWThorsten Wahlers
Thorsten Wahlers

1 August 2022 in Heart, Lung and Circulation
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Journal Article
Closed access
Ilija DjordjevicIlija Djordjevic
Ilija Djordjevic
BIBorko Ivanov
Borko Ivanov
ASAnton Sabashnikov
Anton Sabashnikov
CGChristopher Gaisendrees
Christopher Gaisendrees
Stephen GerferStephen Gerfer
Stephen Gerfer
TWThorsten Wahlers
Thorsten Wahlers

4 December 2022 in The Thoracic and Cardiovascular Surgeon
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Journal Article
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AEAhmed Elderia
Ahmed Elderia
Stephen GerferStephen Gerfer
Stephen Gerfer
Kaveh EghbalzadehKaveh Eghbalzadeh
Kaveh Eghbalzadeh
MAMatti Adam
Matti Adam
SBStephan Baldus
Stephan Baldus
TWThorsten C.W. Wahlers
Thorsten C.W. Wahlers
Background Coronary artery disease (CAD) is frequently diagnosed in patients with aortic valve stenosis. Treatment options include surgical and interventional approaches. We therefore analyzed short-term outcomes of patients undergoing either coronary artery bypass grafting with simultaneous aortic valve replacement (CABG + AVR) or staged percutaneous coronary intervention and transcatheter aortic valve implantation (PCI + TAVI). Methods From all patients treated since 2017, we retrospectively identified 237 patients undergoing TAVI within 6 months after PCI and 241 patients undergoing combined CABG + AVR surgery. Propensity score matching was performed, resulting in 101 matched pairs. Results Patients in the CABG + AVR group were younger compared with patients in the PCI + TAVI group (71.9 ± 4.9 vs 81.4 ± 3.6 years; p < 0.001). The overall mortality at 30 days before matching was higher after CABG + AVR than after PCI + TAVI (7.8 vs 2.1%; p = 0.012). The paired cohort was balanced for both groups regarding demographic variables and the risk profile (age: 77.2 ± 3.7 vs78.5 ± 2.7 years; p = 0.141) and EuroSCORE II (6.2 vs 7.6%; p = 0.297). At 30 days, mortality was 4.9% in the CABG + AVR group and 1.0% in the PCI + TAVI group (p = 0.099). Rethoracotomy was necessary in 7.9% in the CABG + AVR, while conversion to open heart surgery was necessary in 2% in the PCI + TAVI group. The need for new pacemaker was lower after CABG + AVR than after PCI + TAVI (4.1 vs 6.9%; p = 0.010). No paravalvular leak (PVL) was noted in the CABG + AVR group, while the incidence of moderate-to-severe PVL after PCI + TAVI was 4.9% (p = 0.027). Conclusion A staged interventional approach comprises a short-term survival advantage compared with combined surgery for management of CAD and aortic stenosis. However, PCI + TAVI show a significantly higher risk of atrioventricular block and PVL. Further long-term trials are warranted.

10 February 2023 in Life
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Journal Article
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IKIhor Krasivskyi
Ihor Krasivskyi
CGClara Großmann
Clara Großmann
MDMarit Dechow
Marit Dechow
Ilija DjordjevicIlija Djordjevic
Ilija Djordjevic
Borko IvanovBorko Ivanov
Borko Ivanov
TWThorsten Wahlers
Thorsten Wahlers
The use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for cardiogenic shock is rising. Acute limb ischaemia remains one of the main complications after ECMO initiation. We analysed 104 patients from our databank from January 2015 to December 2021 who were supported with mobile ECMO therapy. We aimed to identify the impact of acute limb ischaemia on short-term outcomes in patients placed on ECMO in our institution. The main indication for ECMO therapy was left ventricular (LV) failure with cardiogenic shock (57.7%). Diameters of arterial cannulas (p = 0.365) showed no significant differences between both groups. Furthermore, concomitant intra-aortic balloon pump (IABP, p = 0.589) and Impella (p = 0.385) implantation did not differ significantly between both groups. Distal leg perfusion was established in approximately 70% of patients in two groups with no statistically significant difference (p = 0.960). Acute limb ischaemia occurred in 18.3% of cases (n = 19). In-hospital mortality was not significantly different (p = 0.799) in both groups. However, the bleeding rate was significantly higher (p = 0.005) in the limb ischaemia group compared to the no-limb ischaemia group. Therefore, early diagnosis and prevention of acute limb ischaemia might decrease haemorrhage complications in patients during ECMO therapy.

24 March 2021 in The Thoracic and Cardiovascular Surgeon
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Journal Article
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VMVictor Mauri
Victor Mauri
Stephen GerferStephen Gerfer
Stephen Gerfer
EKElmar Kuhn
Elmar Kuhn
MAMatti Adam
Matti Adam
Kaveh EghbalzadehKaveh Eghbalzadeh
Kaveh Eghbalzadeh
TWThorsten Wahlers
Thorsten Wahlers
Background Rapid deployment aortic valve replacement (RDAVR) and transcatheter aortic valve implantation (TAVI) have emerged as increasingly used alternatives to conventional aortic valve replacement to treat patients at higher surgical risk. Therefore, in this single-center study, we retrospectively compared clinical outcomes and hemodynamic performance of two self-expanding biological prostheses, the sutureless and rapid deployment valve (RDV) Perceval-S (PER) and the transcatheter heart valve (THV) ACURATE neo/TF (NEO) in a 1:1 propensity-score-matching (PSM) patient cohort. Methods A total of 332 consecutive patients with symptomatic aortic valve stenosis underwent either singular RDAVR with PER (119) or TAVI with NEO (213) at our institutions between 2012 and 2017. To compare the unequal patient groups, a 1:1 PSM for preoperative data and comorbidities was conducted. Afterward, 59 patient pairs were compared with regard to relevant hemodynamic parameter, relevant paravalvular leak (PVL), permanent postoperative pacemaker (PPM) implantation rate, and clinical postoperative outcomes. Results Postoperative clinical short-term outcomes presented with slightly higher rates for 30-day all-cause mortality (PER = 5.1% vs. NEO = 1.7%, p = 0.619) and major adverse cardiocerebral event in PER due to cerebrovascular events (transient ischemic attack [TIA]-PER = 3.4% vs. TIA-NEO = 1.7%, p = 0.496 and Stroke-PER = 1.7% vs. Stroke-NEO = 0.0%, p = 1). Moreover, we show comparable PPM rates (PER = 10.2% vs. NEO = 8.5%, p = 0.752). However, higher numbers of PVL (mild—PER = 0.0% vs. NEO = 55.9%, p = 0.001; moderate or higher—PER = 0.0% vs. NEO = 6.8%, p = 0.119) after TAVI with NEO were observed. Conclusion Both self-expanding bioprostheses, the RDV-PER and THV-NEO provide a feasible option in elderly and patients with elevated perioperative risk. However, the discussed PER collective showed more postoperative short-term complications with regard to 30-day all-cause mortality and cerebrovascular events, whereas the NEO showed higher rates of PVL. S.G. and V.M. contributed to study design, data collection, data analysis and interpretation, and writing of the manuscript; both authors contributed equally to this work. E.K., M.A., K.E., and T.R. contributed to data collection and data analysis/interpretation. I. D., B.I., and C.G. contributed to collection of data and literature search. C.F., T.S., and N.M. contributed to data analysis and interpretation. S.B., O.L., and T. W. contributed to data analysis and interpretation, review, and correction of the manuscript. * Both authors contributed equally to this work. Received: 13 September 2020 Accepted: 25 November 2020 Publication Date: 24 March 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany