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502 result(s) for "Hamm, Christian"
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Transcatheter or Surgical Treatment of Aortic-Valve Stenosis
A randomized trial that enrolled patients with severe aortic stenosis at low or intermediate surgical risk showed that transcatheter aortic-valve implantation was noninferior to surgical aortic-valve replacement at 1 year.
Comparison of Diagnostic Value of a Novel Noninvasive Coronary Computed Tomography Angiography Method Versus Standard Coronary Angiography for Assessing Fractional Flow Reserve
Noninvasive fractional flow reserve (FFR) from coronary computed tomography angiography (cCTA) correlates well with invasive FFR and substantially improves the detection of obstructive coronary artery disease. However, with current algorithms, computed tomography (CT)–based FFR is derived off-site in an involved time-consuming manner. We sought to investigate the diagnostic performance of a novel CT-based FFR algorithm, developed for time-efficient in-hospital evaluation of hemodynamically indeterminate coronary lesions. In a blinded fashion, CT-based FFR was assessed in 67 coronary lesions of 53 patients. Pressure guidewire–based FFR <0.80 served as the reference standard to define hemodynamically significant stenosis and assess the diagnostic performance of CT-based FFR compared with standard evaluation of cCTA (luminal diameter stenosis of ≥50%). We recorded the time needed for derivation of CT-based FFR. On a per-lesion and per-patient basis, CT-based FFR resulted in a sensitivity of 85% and 94%, a specificity of 85% and 84%, a positive predictive value of 71% and 71%, and a negative predictive value of 93% and 97%, respectively. The area under the receiver operating characteristic curve on a per-lesion basis was significantly greater for CT-based FFR compared with standard evaluation of cCTA (0.92 vs 0.72, p = 0.0049). A similar trend, albeit not statistically significant, was observed on per-patient analysis (0.91 vs 0.78, p = 0.078). Mean total time for CT-based FFR was 37.5 ± 13.8 minutes. In conclusion, the CT-based FFR algorithm evaluated here outperforms standard evaluation of cCTA for the detection of hemodynamically significant stenoses while allowing on-site application within clinically viable time frames. •We investigated the diagnostic performance of a computed tomography (CT)–based fractional flow reserve (FFR) algorithm.•Hemodynamically indeterminate coronary lesions were evaluated.•CT-based FFR resulted in a sensitivity of 85% and 94% and specificity of 85% and 84%.•CT-based FFR algorithm allows application within clinically viable time frames.
Application of High-Sensitivity Troponin in Suspected Myocardial Infarction
Data from 15 international cohorts of patients with suspected acute MI were used to create and validate a risk-assessment tool integrating high-sensitivity troponin I or T at presentation, the change during serial sampling, and the time between samples to estimate the probability of MI on ED presentation and 30-day outcomes.
Outcome of patients with heart failure after transcatheter aortic valve implantation
Patients with aortic stenosis (AS) may have concomitant heart failure (HF) that determines prognosis despite successful transcatheter aortic valve implantation (TAVI). We compared outcomes of TAVI patients with low stroke volume index (SVI) ≤35 ml/m2 body surface area in different HF classes. Patients treated by transfemoral TAVI at our center (n = 1822) were classified as 1) 'HF with preserved ejection fraction (EF)' (HFpEF, EF ≥50%), 2) 'HF with mid-range EF' (HFmrEF, EF 40-49%), or 3) 'HF with reduced EF' (HFrEF, EF <40%). Patients with SVI >35 ml/m2 served as controls. The prevalence of cardiovascular disease and symptoms increased stepwise from controls (n = 968) to patients with HFpEF (n = 591), HFmrEF (n = 97), and HFrEF (n = 166). Mortality tended to be highest in HFrEF patients 30 days post-procedure, and it became significant after one year: 10.2% (controls), 13.5% (HFpEF), 13.4% (HFmrEF), and 23.5% (HFrEF). However, symptomatic improvement in survivors of all groups was achieved in the majority of patients without differences among groups. Patients with AS and HF benefit from TAVI with respect to symptom alleviation. TAVI in patients with HFpEF and HFmrEF led to an identical, favorable post-procedural prognosis that was significantly better than that of patients with HFrEF, which remains a high-risk population.
Right bundle branch block is not associated with worse short- and mid-term outcome after transcatheter aortic valve implantation
Transcatheter aortic valve implantation (TAVI) is the standard treatment option for patients with severe aortic stenosis (AS) at intermediate or high surgical risk. Preexisting right bundle branch block (RBBB) is a strong predictor of new pacemaker implantation (PPM) after TAVI, and previous data indicate a worse short- and long-term outcome of patients. The aim of this study was to investigate whether preexisting RBBB has an effect on the short- and mid-term outcome of patients undergoing TAVI in a German high-volume TAVI center. For the present retrospective analysis, a total of 1,891 patients with native severe AS with successful TAVI without preexisting PPM were included. The primary endpoint was all-cause mortality after 30 days and 12 months. Baseline RBBB was present in 190 (10.1%) of cases. Preexisting RBBB is a common finding in patients with severe AS undergoing TAVI and is associated with considerably higher PPM rates but not with worse short- and mid-term outcome.
Intracoronary Bone Marrow–Derived Progenitor Cells in Acute Myocardial Infarction
The infusion of bone marrow–derived progenitor cells into the infarct-related coronary artery after an acute myocardial infarction was associated with an absolute increase in the ejection fraction of 5.5%. Determining whether this modest improvement in ventricular function will translate into a long-term clinical benefit will require larger trials with longer follow-up. The infusion of bone marrow–derived progenitor cells into the infarct-related coronary artery after an acute myocardial infarction was associated with an absolute increase in the ejection fraction of 5.5%. Prompt reperfusion of the infarct-related coronary artery has considerably improved the clinical outcome in patients with acute myocardial infarction. 1 Although contemporary reperfusion strategies using stent implantation and aggressive inhibition of platelet aggregation have been shown to increase myocardial salvage, 2 improvements in global left ventricular function are rather modest, despite the use of optimal reperfusion therapy. 3 , 4 Heart failure that develops after infarction remains a major cause of morbidity and mortality. 5 , 6 Experimental studies suggested that intravascular or intramyocardial administration of progenitor cells derived from bone marrow (BMC) or blood may contribute to functional regeneration of infarcted myocardium and enhance neovascularization . . .
Detection of viral SARS‐CoV‐2 genomes and histopathological changes in endomyocardial biopsies
Aims Since December 2019, the novel coronavirus SARS‐CoV‐2 has spread rapidly throughout China and keeps the world in suspense. Cardiovascular complications with myocarditis and embolism due to COVID‐19 have been reported. SARS‐CoV‐2 genome detection in the heart muscle has not been demonstrated so far, and the underlying pathophysiological mechanisms remain to be investigated. Methods and results Endomyocardial biopsies (EMBs) of 104 patients (mean age: 57.90 ± 16.37 years; left ventricular ejection fraction: 33.7 ± 14.6%, sex: n = 79 male/25 female) with suspected myocarditis or unexplained heart failure were analysed. EMB analysis included histology, immunohistochemistry, and detection of SARS‐CoV‐2 genomes by real‐time reverse transcription polymerase chain reaction in the IKDT Berlin, Germany. Among 104 EMBs investigated, five were confirmed with SARS‐CoV‐2 infected by reverse real‐time transcriptase polymerase chain reaction. We describe patients of different history of symptoms and time duration. Additionally, we investigated histopathological changes in myocardial tissue showing that the inflammatory process in EMBs seemed to permeate vascular wall leading to small arterial obliteration and damage. Conclusions This is the first report that established the evidence of SARS‐CoV‐2 genomes detection in EMBs. In these patients, myocardial injury ischaemia may play a role, which could explain the ubiquitous troponin increases. EMB‐based identification of the cause of myocardial injury may contribute to explain the different evolution of complicated SARS‐CoV‐2‐infection and to design future specific and personalized treatment strategies.
Purinergic Regulation of Endothelial Barrier Function
Increased vascular permeability is a hallmark of several cardiovascular anomalies, including ischaemia/reperfusion injury and inflammation. During both ischaemia/reperfusion and inflammation, massive amounts of various nucleotides, particularly adenosine 5′-triphosphate (ATP) and adenosine, are released that can induce a plethora of signalling pathways via activation of several purinergic receptors and may affect endothelial barrier properties. The nature of the effects on endothelial barrier function may depend on the prevalence and type of purinergic receptors activated in a particular tissue. In this review, we discuss the influence of the activation of various purinergic receptors and downstream signalling pathways on vascular permeability during pathological conditions.
Nature’s Load-Bearing Design Principles and Their Application in Engineering: A Review
Biological structures optimized through natural selection provide valuable insights for engineering load-bearing components. This paper reviews six key strategies evolved in nature for efficient mechanical load handling: hierarchically structured composites, cellular structures, functional gradients, hard shell–soft core architectures, form follows function, and robust geometric shapes. The paper also discusses recent research that applies these strategies to engineering design, demonstrating their effectiveness in advancing technical solutions. The challenges of translating nature’s designs into engineering applications are addressed, with a focus on how advancements in computational methods, particularly artificial intelligence, are accelerating this process. The need for further development in innovative material characterization techniques, efficient modeling approaches for heterogeneous media, multi-criteria structural optimization methods, and advanced manufacturing techniques capable of achieving enhanced control across multiple scales is underscored. By highlighting nature’s holistic approach to designing functional components, this paper advocates for adopting a similarly comprehensive methodology in engineering practices to shape the next generation of load-bearing technical components.
Vascular alterations among male elite athletes recovering from SARS-CoV-2 infection
SARS-CoV-2 may affect the cardiovascular system and vascular impairment has been reported in healthy young adults recovering from COVID-19. However, the impact of SARS-CoV-2 infection on the vascular function of elite athletes is unknown. We examined 30 healthy male elite athletes (age 25.8 ± 4.6 years) pre-season and at a 6-month follow-up (182 ± 10 days). Vascular function and central blood pressure were calculated using transfer function-based analysis of peripheral arterial waveforms obtained by oscillometry. We performed a two-way repeated-measures ANOVA on the biomarker data, with SARS-CoV-2 status as the between-groups factor and time as the within-groups factor. Subjects who tested positive for SARS-CoV-2 were studied 18 ± 4 days after their positive testing date at follow-up. Of 30 athletes, 15 tested positive for SARS-CoV-2 after the first examination and prior to the follow-up. None had severe COVID-19 or reported any persisting symptoms. The results of the two-way repeated measures ANOVA revealed that there was no significant main effect of COVID-19 on any of the investigated biomarkers. However, there was a significant interaction between the effects of SARS-CoV-2 exposure and time on augmentation index (Aix) ( p  = 0.006) and augmentation index normalized to a heart rate of 75 beats per minute (Aix@75), ( p  = 0.0018). The observation of an interaction effect on Aix and Aix@75 in the absence of any main effect indicates a cross-over interaction. Significant vascular alterations in male elite athletes recovering from COVID-19 were observed that suggest vascular impairment. Whether these alterations affect athletic performance should be evaluated in future studies.