Incidence and predictors of implantable cardioverter-defibrillator therapy and its complications in idiopathic ventricular fibrillation patients

Aims

Idiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac arrest. Implantable cardioverter-defibrillator (ICD) implantation is currently the only treatment option. Limited data are available on the prevalence and complications of ICD therapy in these patients. We sought to investigate ICD therapy and its complications in patients with IVF.

Methods and results

Patients were selected from a national registry of IVF patients. Patients in whom no underlying diagnosis was found during follow-up were eligible for inclusion. Recurrence of ventricular arrhythmia (VA) was derived from medical and ICD records, electrogram records of ICD therapies were used to differentiate between appropriate or inappropriate interventions. Independent predictors for appropriate ICD shock were calculated using cox regression. In 217 IVF patients, recurrence of sustained VAs occurred in 66 patients (30%) during a median follow-up period of 6.1 years. Ten patients died (4.6%). Thirty-eight patients (17.5%) experienced inappropriate ICD therapy, and 32 patients (14.7%) had device-related complications. Symptoms before cardiac arrest [hazard ratio (HR): 2.51, 95% confidence interval (CI): 1.48–4.24], signs of conduction disease (HR: 2.27, 95% CI: 1.15–4.47), and carrier of the DPP6 risk haplotype (HR: 3.24, 1.70–6.17) were identified as independent predictors of appropriate shock occurrence.

Conclusion

Implantable cardioverter-defibrillator therapy is an effective treatment in IVF, treating recurrences of potentially lethal VAs in approximately one-third of patients during long-term follow-up. However, device-related complications and inappropriate shocks were also frequent. We found significant predictors for appropriate ICD therapy. This may imply that these patients require additional management to prevent recurrent events.

Anti-fibrotic Effects of Cardiac Progenitor Cells in a 3D-Model of Human Cardiac Fibrosis

Cardiac fibroblasts play a key role in chronic heart failure. The conversion from cardiac fibroblast to myofibroblast as a result of cardiac injury, will lead to excessive matrix deposition and a perpetuation of pro-fibrotic signaling. Cardiac cell therapy for chronic heart failure may be able to target fibroblast behavior in a paracrine fashion. However, no reliable human fibrotic tissue model exists to evaluate this potential effect of cardiac cell therapy. Using a gelatin methacryloyl hydrogel and human fetal cardiac fibroblasts (hfCF), we created a 3D in vitro model of human cardiac fibrosis. This model was used to study the possibility to modulate cellular fibrotic responses. Our approach demonstrated paracrine inhibitory effects of cardiac progenitor cells (CPC) on both cardiac fibroblast activation and collagen synthesis in vitro and revealed that continuous cross-talk between hfCF and CPC seems to be indispensable for the observed anti-fibrotic effect.

Multimodality imaging for real-time image-guided left ventricular lead placement during cardiac resynchronization therapy implantations

This study was performed to evaluate the feasibility of intra-procedural visualization of optimal pacing sites and image-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT). In fifteen patients (10 males, 68 ± 11 years, 7 with ischemic cardiomyopathy and ejection fraction of 26 ± 5%), optimal pacing sites were identified pre-procedurally using cardiac imaging. Cardiac magnetic resonance (CMR) derived scar and dyssynchrony maps were created for all patients. In six patients the anatomy of the left phrenic nerve (LPN) and coronary sinus ostium was assessed via a computed tomography (CT) scan. By overlaying the CMR and CT dataset onto live fluoroscopy, aforementioned structures were visualized during LV lead implantation. In the first nine patients, the platform was tested, yet, no real-time image-guidance was implemented. In the last six patients real-time image-guided LV lead placement was successfully executed. CRT implant and fluoroscopy times were similar to previous procedures and all leads were placed close to the target area but away from scarred myocardium and the LPN. Patients that received real-time image-guided LV lead implantation were paced closer to the target area compared to patients that did not receive real-time image-guidance (8 mm [IQR 0–22] vs 26 mm [IQR 17–46], p = 0.04), and displayed marked LV reverse remodeling at 6 months follow up with a mean LVESV change of −30 ± 10% and a mean LVEF improvement of 15 ± 5%. Real-time image-guided LV lead implantation is feasible and may prove useful for achieving the optimal LV lead position.

The Prognostic Value of Right Ventricular Deformation Imaging in Early Arrhythmogenic Right Ventricular Cardiomyopathy

OBJECTIVES

The aim of this study was to investigate the prognostic value of echocardiographic deformation imaging in arrhythmogenic right ventricular cardiomyopathy (ARVC) to optimize family screening protocols.

BACKGROUND

ARVC is characterized by variable disease expressivity among family members, which complicates family screening protocols. Previous reports have shown that echocardiographic deformation imaging detects abnormal right ventricular (RV) deformation in the absence of established disease expression in ARVC.

METHODS

First-degree relatives of patients with ARVC were evaluated according to 2010 task force criteria, including RV deformation imaging (n = 128). Relatives fulfilling structural task force criteria were excluded for further analysis. At baseline, deformation patterns of the subtricuspid region were scored as type I (normal deformation), type II (delayed onset, decreased systolic peak, and post-systolic shortening), or type III (systolic stretching and large post-systolic shortening). The final study population comprised relatives who underwent a second evaluation during follow-up. Disease progression was defined as the development of a new 2010 task force criterion during follow-up that was absent at baseline.

RESULTS

Sixty-five relatives underwent a second evaluation after a mean follow-up period of 3.7 ± 2.1 years. At baseline, 28 relatives (43%) had normal deformation (type I), and 37 relatives (57%) had abnormal deformation (type II or III) in the subtricuspid region. Disease progression occurred in 4% of the relatives with normal deformation at baseline and in 43% of the relatives with abnormal deformation at baseline (p < 0.001). Positive and negative predictive values of abnormal deformation were, respectively, 43% (95% confidence interval: 27% to 61%) and 96% (95% confidence interval: 82% to 100%).

CONCLUSIONS

Normal RV deformation in the subtricuspid region is associated with absence of disease progression during nearly 4-year follow-up in relatives of patients with ARVC. Abnormal RV deformation seems to precede the established signs of ARVC. RV deformation imaging may potentially play an important role in ARVC family screening protocols.

Lower retention after retrograde coronary venous infusion compared with intracoronary infusion of mesenchymal stromal cells in the infarcted porcine myocardium

BACKGROUND

Commonly used strategies for cell delivery to the heart are intramyocardial injection and intracoronary (IC) infusion, both having their advantages and disadvantages. Therefore, alternative strategies, such as retrograde coronary venous infusion (RCVI), are explored. The aim of this confirmatory study was to compare cardiac cell retention between RCVI and IC infusion. As a secondary end point, the procedural safety of RCVI is assessed.

METHODS

Four weeks after myocardial infarction, 12 pigs were randomised to receive mesenchymal stromal cells, labelled with Indium-111, via RCVI (n=6) or IC infusion (n=6). Four hours after cell administration, nuclear imaging was performed to determine the number of cells retained in the heart both in vivo and ex vivo. Procedure-related safety measures were reported.

RESULTS

Cardiac cell retention is significantly lower after RCVI compared with IC infusion (in vivo: RCVI: median 2.89% vs IC: median 13.74%, p=0.002, ex vivo: RCVI: median 2.55% vs IC: median 39.40%, p=0.002). RCVI led to development of pericardial fluid and haematomas on the frontal wall of the heart in three cases. Coronary venous dissection after RCVI was seen in three pigs, of which one also developed pericardial fluid and a haematoma. IC infusion led to no flow in one pig.

CONCLUSION

RCVI is significantly less efficient in delivering cells to the heart compared with IC infusion. RCVI led to more procedure-related safety issues than IC infusion, with multiple cases of venous dissection and development of haematomas and pericardial fluid collections.

The influence of LV geometry on the occurrence of abnormal exercise tests in athletes

BACKGROUND

Previous studies revealed a high rate of abnormal exercise test (ET) results in the absence of obstructive coronary artery disease (CAD) in asymptomatic athletes. The physiological background of this phenomenon is not well established. In particular, it is unclear whether sports-induced morphological cardiac adaptations are determinants of abnormal ET results. The main objective of this study was to investigate if healthy asymptomatic recreational and competitive athletes with abnormal ET results without obstructive CAD have a higher LV mass when compared with athletes with normal ET results.

METHODS

Seventy-three athletes with abnormal ET results without presence of obstructive CAD underwent echocardiographic assessment of LV mass, systolic and diastolic measurements. These data were compared with data from 73 athletes with normal ET results, matched for gender, age, body composition, sports characteristics and exercise capacity.

RESULTS

No significant increase in LV mass (161.9 ± 39 g vs. 166.9 ± 42.1 g, p = 0.461) was found between groups. Athletes with abnormal ET results had a significant thicker IVSd (9.7 ± 1.8 mm vs. 9.0 ± 1.7 mm, p = 0.014), higher IVSd/PWTd ratio (1.08 ± 0.20 vs. 1.00 ± 0.12, p = 0.011) and deceleration time (DT) was prolonged ((225.14 ± 55.08 vs. 199.96 ± 34.65, p = 0.003).

CONCLUSION

Athletes with abnormal ET result did not show a higher in LV mass when compared to athletes with a normal ET result. However, a pattern of asymmetric cardiac remodeling, together with altered diastolic function is present. Due to small differences, cardiac remodeling only plays a limited role in the occurrence of positive ET results in athletes.

O2 Pulse Patterns in Male Master Athletes with Normal and Abnormal Exercise Tests

PURPOSE

The clinical relevance of abnormal exercise testing (ET) results (at least 0.1 mV ST segment depression measured during exercise or recovery in three consecutive beats) in athletes without obstructive coronary artery disease (CAD) is not well understood. It is unknown whether this phenomenon reflects a physiological adaptation to sport or a truly ischemic response and a concomitant attenuated stroke volume (SV) response. The aim of this study was to investigate if athletes with abnormal ET results without obstructive CAD showed signs of an attenuated SV response using cardiopulmonary ET parameters.

METHODS

A total of 78 male master athletes with abnormal ET results without obstructive CAD underwent cardiopulmonary ET. ΔO2 pulse/Δwork rate (WR), ΔV˙O2/ΔWR, and Δheart rate (HR)/ΔWR were assessed and compared with data from 78 male master athletes with normal ET results, matched for age, sports characteristics, and exercise capacity.

RESULTS

The ΔO2 pulse/ΔWR ratio beyond anaerobic threshold in athletes with abnormal ET results was lower than that in athletes with normal ET results (0.73 ± 0.41 vs 1.12 ± 0.54, respectively, P < 0.001). The ΔV˙O2/ΔWR ratio was also lower in athletes with abnormal ET results (0.9 ± 0.2 vs 1.0 ± 0.3, respectively, P = 0.041). Furthermore, these athletes showed a greater increase in HR in the last 2 min of exercise (ΔHR/ΔWR ratio: 1.19 ± 0.5 vs 0.80 ± 0.6, P < 0.001).

CONCLUSION

Athletes with abnormal ET results without obstructive CAD showed an attenuated O2 pulse slope, decreased ΔV˙O2/ΔWR ratio, and increased ΔHR/ΔWR ratio beyond anaerobic threshold when compared with athletes with a normal ET result. These results support the hypothesis that at least a part of the athletes with an abnormal ET in absence of obstructive CAD have an attenuated SV response at high-intensity exercise.

Intramyocardial bone marrow cell injection does not lead to functional improvement in patients with chronic ischaemic heart failure without considerable ischaemia

Background

It has been suggested that bone marrow cell injection may have beneficial effects in patients with chronic ischaemic heart disease. However, previous trials have led to discrepant results of cell-based therapy in patients with chronic heart failure. The aim of this study was to evaluate the efficacy of intramyocardial injection of mononuclear bone marrow cells in patients with chronic ischaemic heart failure with limited stress-inducible myocardial ischaemia.

Methods and results

This multicentre, randomised, placebo-controlled trial included 39 patients with no-option chronic ischaemic heart failure with a follow-up of 12 months. A total of 19 patients were randomised to autologous intramyocardial bone marrow cell injection (cell group) and 20 patients received a placebo injection (placebo group). The primary endpoint was the group difference in change of left ventricular ejection fraction, as determined by single-photon emission tomography. On follow-up at 3 and 12 months, change of left ventricular ejection fraction in the cell group was comparable with change in the placebo group (P = 0.47 and P = 0.08, respectively). Also secondary endpoints, including left ventricle volumes, myocardial perfusion, functional and clinical parameters did not significantly change in the cell group as compared to placebo. Neither improvement was demonstrated in a subgroup of patients with stress-inducible ischaemia (P = 0.54 at 3‑month and P = 0.15 at 12-month follow-up).

Conclusion

Intramyocardial bone marrow cell injection does not improve cardiac function, nor functional and clinical parameters in patients with severe chronic ischaemic heart failure with limited stress-inducible ischaemia.

Clinical Trial Registration: NTR2516

Electronic supplementary material

The online version of this article (10.1007/s12471-018-1213-2) contains supplementary material, which is available to authorized users.

Prevalence and cardiac phenotype of patients with a phospholamban mutation

Pathogenic mutations in the phospholamban (PLN) gene may give rise to inherited cardiomyopathies due to its role in calcium homeostasis. Several PLN mutations have been identified, with the R14del mutation being the most prevalent cardiomyopathy-related mutation in the Netherlands. It is present in patients diagnosed with arrhythmogenic cardiomyopathy as well as dilated cardiomyopathy. Awareness of the phenotype of this PLN mutation is of great importance, since many carriers remain to be identified. Patients with the R14del mutation are characterised by older age at onset, low-voltage electrocardiograms and a high frequency of ventricular arrhythmias. Additionally, these patients have a poor prognosis often with left ventricular dysfunction and early-onset heart failure. Therefore, when there is a suspicion of a PLN mutation, cardiac and genetic screening is strongly recommended.

Novel method for electrode-tissue contact measurement with multi-electrode catheters

Aims

With multi-electrode catheters, measuring contact force (CF) on each electrode is technically challenging. Present electrical methods, like the electrical coupling index (ECI) may yield false positive values in pulmonary veins. We developed a novel method that measures electrode-interface resistance (IR) by applying a very local electrical field between neighbouring catheter electrodes while measuring voltage between each catheter electrode and a skin patch. The aim of this study was to evaluate the new IR method to measure electrode-tissue contact.

Methods and results

In vitro, effects of remote high-impedance structures were studied. In addition, both ECI and IR were directly compared with true electrode-tissue CF. In five pigs, the influence of high-impedance pulmonary tissue on ECI and IR was investigated while navigating the free floating catheter into the caval veins. Inside the left atrium (LA), IR was directly compared with CF. Finally, multi-electrode IR measurements in the LA and inferior pulmonary vein (IPV) were compared. In vitro, IR is much less affected by remote high-impedance structures than ECI (3% vs. 32%). Both IR and ECI strongly relate to electrode-tissue CF (r2 = 0.84). In vivo, and in contrast to ECI, IR was not affected by nearby pulmonary tissue. Inside the LA, a strong relation between IR and CF was found. This finding was confirmed by simultaneous multi-electrode measurements in LA and IPV.

Conclusion

Data of the present study suggest that electrode-tissue contact affects the IR while being highly insensitive to remote structures. This method facilitates electrode-tissue contact measurements with circular multi-electrode ablation catheters.

Cardio-oncology: an overview on outpatient management and future developments

Recent advances in the early detection and treatment of cancer have led to increasing numbers of cancer survivors worldwide. Nonetheless, despite major improvements in the outcome of these patients, long-term side effects of radio- and chemotherapy affect both patient survival and quality of life, independent of the oncological prognosis. Chemotherapy-related cardiac dysfunction is one of the most notorious short-term side effects of anticancer treatment, occurring in ~10% of patients. Progression to overt heart failure carries a strikingly poor prognosis with a 2-year mortality rate of 60%. Early detection of left ventricular damage by periodic monitoring and prompt initiation of heart failure treatment is key in improving cardiovascular prognosis. To meet the growing demand for a specialised interdisciplinary approach for the prevention and management of cardiovascular complications induced by cancer treatment, a new discipline termed cardio-oncology has evolved. However, an uniform, multidisciplinary approach is currently lacking in the Netherlands. This overview provides an introduction and comprehensive summary of this emerging discipline and offers a practical strategy for the outpatient management of this specific patient population.

RV adaptation to increased afterload in congenital heart disease and pulmonary hypertension

Background

The various conditions causing a chronic increase of RV pressure greatly differ in the occurrence of RV failure, and in clinical outcome. To get a better understanding of the differences in outcome, RV remodeling, longitudinal function, and transverse function are compared between patients with pulmonary stenosis (PS), those with a systemic RV and those with pulmonary hypertension (PH).

Materials and methods

This cross-sectional study prospectively enrolled subjects for cardiac magnetic resonance imaging (CMR), functional echocardiography and cardiopulmonary exercise testing. The study included: controls (n = 37), patients with PS (n = 15), systemic RV (n = 19) and PH (n = 20). Statistical analysis was performed using Analysis of Variance (ANOVA) with posthoc Bonferroni.

Results

PS patients had smaller RV volumes with higher RV ejection fraction (61.1±9.6%; p<0.05) compared to controls (53.8±4.8%). PH and systemic RV patients exhibited dilated RVs with lower RV ejection fraction (36.9±9.6% and 46.3±10.1%; p<0.01 versus controls). PH patients had lower RV stroke volume (p = 0.02), RV ejection fractions (p<0.01) and VO₂ peak/kg% (p<0.001) compared to systemic RV patients. Mean apical transverse RV free wall motion was lower and RV free wall shortening (p<0.001) was prolonged in PH patients–resulting in post-systolic shortening and intra-ventricular dyssynchrony. Apical transverse shortening and global longitudinal RV deformation showed the best correlation to RV ejection fraction (respectively r = 0.853, p<0.001 and r = 0.812, p<0.001).

Conclusions

RV remodeling and function differed depending on the etiology of RV pressure overload. In contrast to the RV of patients with PS or a systemic RV, in whom sufficient stroke volumes are maintained, the RV of patients with PH seems unable to compensate for its increase in afterload completely. Key mediators of RV dysfunction observed in PH patients, were: prolonged RV free wall shortening, resulting in post-systolic shortening and intra-ventricular dyssynchrony, and decreased transverse function.

Non-cardiac chest pain: prognosis and secondary healthcare utilisation

Objective

Presentations of non-cardiac chest pain (NCCP) to the emergency department (ED) are increasing. More knowledge of prognosis and healthcare utilisation of patients with NCCP is necessary to optimise their management.

Methods

This study is a prospective, observational, prevalence-based cohort study conducted from September 2015 to February 2016 with 1-year follow-up including all patients 18 years and older referred to the ED with chest pain. Discharge diagnoses, mortality, major adverse cardiac events (MACE), re-presentations to the ED, hospitalisations, cardiac interventions and outpatient monitoring were assessed.

Results

More than 60% of the 1239 patients presenting with chest pain were discharged with NCCP. The all-cause 1-year mortality rate of patients with NCCP was 2.3% compared with 7.2% in patients with cardiac chest pain (CCP) (p<0.001) and the occurrence of MACE was 5.1% vs 8.3%, respectively (p=0.026). Previous history of coronary artery disease (CAD) in patients with NCCP was identified as a predictive factor for MACE (OR 4.30 (95% CI 1.24 to 14.89), p=0.021). Patients with NCCP had more non-invasive interventions than patients with CCP (proportion of 0.225 vs 0.165 per patient, p<0.001) and 13.7% of patients with NCCP re-presented at the ED within 1  year.

Conclusion

The majority of patients referred to the ED with chest pain are discharged with NCCP. The prognosis of patients with NCCP is better than patients with CCP; however, they are at risk for MACE due to a history of CAD. Patients with NCCP moreover use a substantial amount of medical resources, stressing the importance of good triage to minimise unnecessary healthcare utilisation while still preventing MACE.

Engineering CRISPR/Cpf1 with tRNA promotes genome editing capability in mammalian systems

CRISPR/Cpf1 features a number of properties that are distinct from CRISPR/Cas9 and provides an excellent alternative to Cas9 for genome editing. To date, genome engineering by CRISPR/Cpf1 has been reported only in human cells and mouse embryos of mammalian systems and its efficiency is ultimately lower than that of Cas9 proteins from Streptococcus pyogenes. The application of CRISPR/Cpf1 for targeted mutagenesis in other animal models has not been successfully verified. In this study, we designed and optimized a guide RNA (gRNA) transcription system by inserting a transfer RNA precursor (pre-tRNA) sequence downstream of the gRNA for Cpf1, protecting gRNA from immediate digestion by 3'-to-5' exonucleases. Using this new gRNAtRNA system, genome editing, including indels, large fragment deletion and precise point mutation, was induced in mammalian systems, showing significantly higher efficiency than the original Cpf1-gRNA system. With this system, gene-modified rabbits and pigs were generated by embryo injection or somatic cell nuclear transfer (SCNT) with an efficiency comparable to that of the Cas9 gRNA system. These results demonstrated that this refined gRNAtRNA system can boost the targeting capability of CRISPR/Cpf1 toolkits.

Suppression of T cells by mesenchymal and cardiac progenitor cells is partly mediated via extracellular vesicles

Adverse remodeling after myocardial infarction (MI) is strongly influenced by T cells. Stem cell therapy after MI, using mesenchymal stem cells (MSC) or cardiomyocyte progenitor cells (CMPC), improved cardiac function, despite low cell retention and limited differentiation. As MSC secrete many factors affecting T cell proliferation and function, we hypothesized the immune response could be affected as one of the targets of stem cell therapy. Therefore, we studied the immunosuppressive properties of human BM-MSC and CMPC and their extracellular vesicles (EVs) in co-culture with activated T cells. Proliferation of T cells, measured by carboxyfluorescein succinimidyl ester dilution, was significantly reduced in the presence of BM-MSC and CMPC. The inflammatory cytokine panel of the T cells in co-culture, measured by Luminex assay, changed, with strong downregulation of IFN-gamma and TNF-alpha. The effect on proliferation was observed in both direct cell contact and transwell co-culture systems. Transfer of conditioned medium to unrelated T cells abrogated proliferation in these cells. EVs isolated from the conditioned medium of BM-MSC and CMPC prevented T cell proliferation in a dose-dependent fashion. Progenitor cells presence induces up- and downregulation of multiple previously unreported pathways in T cells. In conclusion, both BM-MSC and CMPC have a strong capacity for in vitro immunosuppression. This effect is mediated by paracrine factors, such as extracellular vesicles. Besides proliferation, many additional pathways are influenced by both BM-MSC and CMPC.

MMISH: Multicolor microRNA in situ hybridization for paraffin embedded samples

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A robust, sensitive and flexible multicolor miRNA in situ hybridization (MMISH) technique for paraffin embedded sections can be combined with both immunohistochemical and immunofluorescent staining.

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Usage of urea in our buffers which enhances the target-probe affinity by preventing intermolecular interaction within miRNAs or individual probes, and by reversing the EDC fixation induced epitope loss by denaturing the antigens, less toxic compared to toxic formamide.

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Second, it can be combined with immunofluorescent stainings, which allows one to analyze the expression and precise (sub)cellular location of the miRNA of interest.

To understand and assess the roles of miRNAs, visualization of the expression patterns of specific miRNAs is needed at the cellular level in a wide variety of different tissue types. Although miRNA in situ hybridization techniques have been greatly improved in recent years, they remain difficult to routinely perform due to the complexity of the procedure. In addition, as it is crucial to define which tissues or cells are expressing a particular miRNA in order to elucidate the biological function of the miRNA, incorporation of additional stainings for different cellular markers is necessary. Here, we describe a robust and flexible multicolor miRNA in situ hybridization (MMISH) technique for paraffin embedded sections. We show that the miRNA in situ protocol is sensitive and highly specific and can successfully be combined with both immunohistochemical and immunofluorescent stainings.

How I do it: feasibility of a new ultrasound probe fixator to facilitate high quality stress echocardiography

Background

Stress echocardiography (SE) has recently regained momentum as an important diagnostic tool for the assessment of both ischemic and non-ischemic heart disease. Performing SE during physical exercise is challenging due to a suboptimal patient position and vigorous movements of the patient’s chest. This hampers a stable ultrasound position and reduces the diagnostic performance of SE. A stable ultrasound probe position would facilitate producing high quality images during continuous measurements. With Probefix (Usono, Eindhoven, The Netherlands), a newly developed tool to fixate the ultrasound probe to the patient’s chest, stabilization of the probe during physical exercise is possible.

Implementation and results

The technique of SE with the Probefix and its’ feasibility are evaluated in a small pilot study. Probefix fixates the ultrasound probe to the patient’s chest, using two chest straps and a fixation device. The ultrasound probe position and angle may be altered with a relative high degree of freedom. We tested the Probefix for continuous echocardiographic imaging in 12 study subjects during supine and upright ergometer stress tests. One patient was unable to perform exercise and in two study subjects good quality images were not achieved. In the other patients (82%) a stable probe position was obtained, with subsequent good quality echocardiographic images during SE.

Conclusion

We have demonstrated the feasibility of the Probefix support during ergometer tests in supine and upright positions and conclude that this external fixator may facilitate continuous monitoring of cardiac function in a group of patients.

Electronic supplementary material

The online version of this article (10.1186/s12947-018-0124-0) contains supplementary material, which is available to authorized users.

Renin and aldosterone are not associated with vulnerable plaque characteristics in patients with carotid artery disease

BACKGROUND

The renin-angiotensin-aldosterone system is increasingly being recognized to play an important role in the development and clinical course of cardiovascular diseases. Renin-angiotensin-aldosterone system activation is associated with clinical outcome in various populations of cardiovascular patients, such as patients with coronary artery, peripheral artery, and cerebrovascular disease. In this study, we investigated the associations between plasma renin and aldosterone concentrations and atherosclerotic plaque characteristics and secondary vascular events in patients undergoing carotid endarterectomy.

METHODS AND RESULTS

Baseline plasma renin and aldosterone concentrations from 506 subjects undergoing carotid endarterectomy (mean age, 67 ± 9 years; 65% male) were correlated with histopathologic characteristics and inflammatory protein concentrations of the excised atherosclerotic plaque. Ordinal logistic regression (for ordinal outcome parameters) or linear regression (for linear outcome) analysis did not show a statistically significant relationship between plasma renin or aldosterone concentrations and plaque fat, thrombus, calcifications, collagen, smooth muscle cells, or macrophage content. Neither could any association be found with intraplaque inflammatory mediators. During a median follow-up of 3 years, 102 (20%) patients experienced a major secondary vascular event (composite of stroke, myocardial infarction, leg amputation, vascular death, or coronary revascularization or peripheral intervention). In multivariable Cox regression analysis, including both renin and aldosterone, baseline renin concentrations were associated with the occurrence of secondary events.

CONCLUSIONS

In patients with established atherosclerotic disease undergoing carotid endarterectomy, plasma renin and aldosterone concentrations were not associated with atherosclerotic plaque characteristics. Plasma renin concentration was positively associated with the occurrence of major secondary vascular events.