Christoph Waldeyer

Popeye domain containing proteins are essential for stress-mediated modulation of cardiac pacemaking in mice

Cardiac pacemaker cells create rhythmic pulses that control heart rate; pacemaker dysfunction is a prevalent disorder in the elderly, but little is known about the underlying molecular causes. Popeye domain containing (Popdc) genes encode membrane proteins with high expression levels in cardiac myocytes and specifically in the cardiac pacemaking and conduction system. Here, we report the phenotypic analysis of mice deficient in Popdc1 or Popdc2. ECG analysis revealed severe sinus node dysfunction when freely roaming mutant animals were subjected to physical or mental stress. In both mutants, bradyarrhythmia developed in an age-dependent manner. Furthermore, we found that the conserved Popeye domain functioned as a high-affinity cAMP-binding site. Popdc proteins interacted with the potassium channel TREK-1, which led to increased cell surface expression and enhanced current density, both of which were negatively modulated by cAMP. These data indicate that Popdc proteins have an important regulatory function in heart rate dynamics that is mediated, at least in part, through cAMP binding. Mice with mutant Popdc1 and Popdc2 alleles are therefore useful models for the dissection of the mechanisms causing pacemaker dysfunction and could aid in the development of strategies for therapeutic intervention.

Prognostic Value of Iron-Homeostasis Regulating Peptide Hepcidin in Coronary Heart Disease—Evidence from the Large AtheroGene Study

Iron is essential in terms of oxygen utilization and mitochondrial function. The liver-derived peptide hepcidin has been recognized as a key regulator of iron homeostasis. Since iron metabolism is crucially linked to cardiovascular health, and low hepcidin was proposed as potential new marker of iron metabolism, we aimed to evaluate the prognostic value of hepcidin in a large cohort of patients with coronary heart disease (CHD). Serum levels of hepcidin were determined at baseline in patients with angiographically documented CHD. The main outcome measure was non-fatal myocardial infarction (MI) or cardiovascular death. During a median follow-up of 4.1 years, 10.3% experienced an endpoint. In Cox regression analyses for hepcidin the hazard ratio for future cardiovascular death or MI was 1.03 (95% confidence interval (CI) 0.91–1.18, p = 0.63) after adjustment for sex and age. This association virtually did not change after additional adjustment for body mass index (BMI), smoking status, hypertension, diabetes, dyslipidemia, and surrogates of cardiac function (NT-proBNP), size of myocardial necrosis (troponin I), and anemia (hemoglobin). In this study, by far the largest evaluating the predictive value of hepcidin, hepcidin levels were not associated with future MI or cardiovascular death. This implicates a limited, if any, role for hepcidin in secondary cardiovascular risk prediction.

Adverse Outcome Prediction of Iron Deficiency in Patients with Acute Coronary Syndrome

Acute myocardial infarction remains a leading cause of morbidity and mortality. While iron deficient heart failure patients are at increased risk of future cardiovascular events and see improvement with intravenous supplementation, the clinical relevance of iron deficiency in acute coronary syndrome remains unclear. We aimed to evaluate the prognostic value of iron deficiency in the acute coronary syndrome (ACS). Levels of ferritin, iron, and transferrin were measured at baseline in 836 patients with ACS. A total of 29.1% was categorized as iron deficient. The prevalence of iron deficiency was clearly higher in women (42.8%), and in patients with anemia (42.5%). During a median follow-up of 4.0 years, 111 subjects (13.3%) experienced non-fatal myocardial infarction (MI) and cardiovascular mortality as combined endpoint. Iron deficiency strongly predicted non-fatal MI and cardiovascular mortality with a hazard ratio (HR) of 1.52 (95% confidence interval (CI) 1.03-2.26; p = 0.037) adjusted for age, sex, hypertension, smoking status, diabetes, hyperlipidemia, body-mass-index (BMI) This association remained significant (HR 1.73 (95% CI 1.07–2.81; p = 0.026)) after an additional adjustment for surrogates of cardiac function and heart failure severity (N-terminal pro B-type natriuretic peptide, NT-proBNP), for the size of myocardial necrosis (troponin), and for anemia (hemoglobin). Survival analyses for cardiovascular mortality and MI provided further evidence for the prognostic relevance of iron deficiency (HR 1.50 (95% CI 1.02–2.20)). Our data showed that iron deficiency is strongly associated with adverse outcome in acute coronary syndrome.

Distinct Hemodynamic Changes After Interventional Mitral Valve Edge‐to‐Edge Repair in Different Phenotypes of Heart Failure: An Integrated Hemodynamic Analysis

Background Percutaneous mitral valve edge‐to‐edge repair (pMVR) with a MitraClip is beneficial for the clinical symptoms of patients irrespective of the ejection fraction (EF). Nevertheless, the consequences on hemodynamics are poorly understood. Therefore, we used data from noninvasive pressure‐volume loops to investigate the left ventricular (LV) remodeling of patients after pMVR dependent on their baseline EF. Methods and Results In 130 patients with successful pMVR, the end‐diastolic pressure‐volume relationship (EDPVR) and end‐systolic pressure‐volume relationship were estimated noninvasively from echocardiographic data. We compared EDPVR and end‐systolic pressure‐volume relationship at discharge and follow‐up between patients with a reduced EF (<40%) and patients with a mid‐ranged or preserved EF (≥40%). Reduced EF was present in 71 patients (54%). Mean follow‐up duration was 277±117 days. We observed a significant reduction in degree of mitral regurgitation and an improvement in functional status at follow‐up irrespective of baseline EF. In patients with a mid‐ranged or preserved EF, the EDPVR and end‐systolic pressure‐volume relationship were shifted leftwards, suggesting an improvement in LV function. In contrast, in patients with a reduced EF, EDPVR and end‐systolic pressure‐volume relationship remained stable, although comparison with the baseline data indicates a rightward shift of the EDPVR. This indicates that there is no improvement in LV function after pMVR in patients with reduced EF. Conclusions The pMVR is associated with improved clinical symptoms in all patient subgroups. However, it leads to different hemodynamic responses. In patients with mid‐ranged or preserved EF, we found reverse remodeling with reduced LV dilatation and increased contractility. In contrast, in patients with reduced EF, we observed no reverse remodeling and no improvement in LV function.

Intrinsic Iron Release Is Associated with Lower Mortality in Patients with Stable Coronary Artery Disease—First Report on the Prospective Relevance of Intrinsic Iron Release

Intrinsic iron release is discussed to have favorable effects in coronary artery disease (CAD). The aim of this study was to evaluate the prognostic relevance of intrinsic iron release in patients with CAD. Intrinsic iron release was based on a definition including hepcidin and soluble transferrin receptor (sTfR). In a cohort of 811 patients with angiographically documented CAD levels of hepcidin and sTfR were measured at baseline. Systemic body iron release was defined as low levels of hepcidin (<24 ng/mL) and high levels of sTfR (≥2 mg/L). A commercially available ELISA (DRG) was used for measurements of serum hepcidin. Serum sTfR was determined by using an automated immunoassay (). Cardiovascular mortality was the main outcome measure. The criteria of intrinsic iron release were fulfilled in 32.6% of all patients. Significantly lower cardiovascular mortality rates were observed in CAD patients with systemic iron release. After adjustment for body mass index, smoking status, hypertension, diabetes, dyslipidemia, sex, and age, the hazard ratio for future cardiovascular death was 0.41. After an additional adjustment for surrogates of the size of myocardial necrosis (troponin I), anemia (hemoglobin), and cardiac function and heart failure severity (N-terminal pro B-type natriuretic peptide), this association did not change (Hazard ratio 0.37 (95% confidence interval 0.14–0.99), p = 0.047). In conclusion, significantly lower cardiovascular mortality rates were observed in CAD patients with intrinsic iron release shown during follow-up.

Adherence to Mediterranean diet, high-sensitive C-reactive protein, and severity of coronary artery disease: Contemporary data from the INTERCATH cohort

BACKGROUND AND AIMS Guidelines recommend a healthy diet as a cornerstone of cardiovascular disease (CVD) prevention. Although the Mediterranean diet (MD) is the best studied dietary pattern for CV outcomes, data on association between MD and severity of CAD are limited. Therefore, we analysed dietary data in association with the SYNTAX score in coronary artery disease (CAD) patients from the INTERCATH study. METHODS The INTERCATH study is an observational study in patients undergoing coronary angiography at the University Heart Center Hamburg. Coronary morphology is assessed by the SYNTAX score. A lifestyle questionnaire collects dietary data with food frequency questions at baseline. Based on seven dietary characteristics, we calculated an established Mediterranean diet score (MDS) with a range of 0-28 points at which 28 points reflect maximal adherence to MD. To investigate the association of MD with severity of CAD, we performed logistic regression analysis after adjustment for confounding factors. RESULTS Of 1121 patients, 27% were women. The median age was 70.7 years (interquartile range (IQR) 61.1,77.0). CV risk factors were distributed as expected for a CAD cohort (31.3% diabetes, 81.1% arterial hypertension, 34.0% smoking, median BMI 26.6 kg/m2 (IQR 24.1, 30.3), median LDL-C 87 mg/dL (IQR 65.0,116,6). Of all variables included, the strongest correlation with MDS was found for log (hs-CRP) (r = -0.21, p < 0.001). Adherence to MD represented by a higher MDS was significantly associated with a reduced probability for a medium/high risk SYNTAX score of ≥23 with an odds ratio (OR) of 0.923 per point increase of MDS (95% confidence interval 0.869-0.979; p = 0.0079). This association remained significant after adjustment for cardiovascular risk factors (OR 0.934, 95% CI 0.877-0.995, p = 0.035). After further adjustment for log (hs-CRP), the association remained no longer significant (OR 0.955 (0.893-1.022, p = 0.19). CONCLUSIONS In this contemporary data set, we found an independent association of adherence to MD with a less complex CAD. Hs-CRP correlated significantly with adherence to MD and may be a marker of the vasoprotective effects of MD. These results strengthen the evidence for the protective effect of an MD pattern in CVD prevention.

Percutaneous coronary intervention for ostial and bifurcation lesions using the Szabo technique: a single centre experience

BACKGROUND Aorto-ostial lesions as well as bifurcation lesions still provide challenges in percutaneous coronary intervention (PCI), as meticulous stent placement is needed. The Szabo-technique, which uses a second wire to anchor the stent at the ostium, may be helpful here. In this article, we will provide detailed information on the technique including video material as well as procedural and long-term follow-up data of a cohort of patients treated with this technique. METHODS A retrospective single-centre study was performed in patients undergoing Szabo-PCI from 2014 to 2016 (N.=28). RESULTS Indications for PCI were elective in 53% and urgent/emergent in 47%. Target vessel was the ostial right coronary artery in 43%, the ostial left main artery in 7%, the proximal left anterior descending artery in 29% and the proximal circumflex artery in 21% of the cases. Primary success rate was 86%. In the other 14%, delivery of the stent failed due to a high-grade calcification. There were no periprocedural complications. During the follow-up time (mean 308 days) there was one case of cardiovascular and one case of non-cardiovascular death without any stroke events. In one case target lesions revascularisation was necessary. CONCLUSIONS The Szabo-technique offers a feasible and safe approach for PCI of ostial and bifurcation lesions. Calcified lesions seem to be a challenging aspect.