TAVI versus SAVR in intermediate-risk patients with severe aortic stenosis and chronic kidney disease: a matched comparison in a subcohort from the GARY registry

Background

According to American and recent European guidelines, both transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) may be used to treat severe aortic stenosis in a subgroup of patients with intermediate surgical risk, in spite of slight differences in recommended age limits (ACC/AHA: 65–80 years and ESC/EACTS: <75 years). A shared therapeutic decision is made with the patient, based on a heart team assessment. For this, individual factors should be taken into account. Concomitant chronic kidney disease (CKD) is a prognostic factor in such patients, and CKD stage ≥3a and ≥3b has been shown to be a significant independent risk factor for SAVR and TAVI, respectively.

Purpose

To compare TAVI vs. SAVR outcomes in a subgroup of patients for whom both therapies could possibly be considered according to current guidelines.

Methods

The large nation-wide German Aortic Valve Registry (GARY) includes data from patients treated with TAVI or SAVR. A subcohort of patients from GARY with intermediate surgical risk (age ≤80 years, STS-score 4–8) and moderate-to-severe chronic kidney disease (CKD stages 3a, 3b, and 4) was selected. A matched analysis of 704 patients undergoing TAVI and 374 undergoing SAVR was carried out using a propensity score method. Primary endpoint was 1-year survival. Clinical complications and specifically the need for postprocedural new-onset dialysis were secondary endpoints.

Results

TAVI and SAVR showed similar survival results at 1 year in a Kaplan-Meier analysis (HR [95% CI] for TAVI: 1.271 [0.795,2.031], p=0.316). Despite a numerically higher post-procedural short-term survival in TAVI patients and a numerically higher 1-year survival in SAVR patients, such differences did not reach statistical significance (96.4% vs. 94.2%, p=0.199, and 86.2% vs. 81.2%, p=0.316, respectively). In weighted analyses, need for permanent pacemaker, vascular complications, and moderate-to-severe valvular regurgitation were significantly more common with TAVI, whereas patients undergoing SAVR had significantly higher rates of myocardial infarction, and transient ischaemic attack, needed more transfusions for bleeding, and had a significantly longer intensive care unit stay and overall hospital stay. The need for new-onset dialysis for a limited time was more common after SAVR (p<0.0001); however, very few patients required chronic dialysis either after TAVI or after SAVR.

Conclusion

In a matched analysis of intermediate-risk patients with severe aortic stenosis and a concomitant moderate-to-severe CKD, for whom both TAVI and SAVR could possibly be considered, both approaches showed excellent and comparable results.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The registry receives financial support in the form of unrestricted grants by medical device companies (Edwards Lifesciences, JenaValve Technology, Medtronic, Sorin, St. Jude Medical, Symetis S.A.).In addition, there is unrestricted support by funding statisticians by the DZHK (Deutsches Zentrum für Herz-Kreislaufforschung).

The human cell atlas of the hypertrophic heart reveals impaired inter-cellular cross-talks

Introduction

The pathophysiology of cardiac hypertrophy is multifactorial and is accompanied by the dysregulation of various signaling pathways contributing to cardiac dysfunction and heart failure. While the hypertrophic response of cardiomyocytes (CM) has been extensively studied, the interplay of CMs with the non-parenchymal cells in the heart is less explored. Here, we apply high-resolution transcriptomic analysis on single cell level allowing the identification of cellular responses and communication in the hypertrophic human heart.

Results

We analyzed single nuclei RNA sequencing data of cardiac tissues from five patients with aortic stenosis and cardiac hypertrophy and 13 matched healthy subjects. Bioinformatic data analysis of 88,536 nuclei followed by clustering led to the identification of specific heterogenic cell type signatures. Analyzing cell type specific gene expression signatures, we found the expected up-regulation of the cardiac stress MYH7 (4.15-fold), CMYA5 (4.89-fold) and XIRP2 (6.13-fold) in cardiomyocytes (CM) (all p<0.0001). Fibroblasts showed increased expression of genes associated with fibrosis and activation markers such as periostin (POSTN; 6.84-fold, p<0.0001). In-silico analysis of intercellular communication pathways revealed a striking downregulation of ligand-receptor interactions between CMs and other cells in hypertrophic compared to healthy controls indicating that CMs are less responsive to signals from fibroblasts and endothelial cells (ECs) in the hypertrophied heart. Particularly, CM showed reduced expression of receptor tyrosine kinases of the Ephrin family and FGF-family members. Specifically, Ephrin-B1 was significantly downregulated in CMs of the hypertrophic hearts (0.01-fold, p<0.0001). The down-regulation of Ephrin-B1 was additionally validated on protein level using histological sections of hypertrophic cardiomyopathy patients (n=6) versus healthy controls (n=5) (0.66-fold, p=0.02). In-vitro studies in neonatal cardiomyocytes further demonstrated that activation of the Ephrin-B1 receptor by the agonist Ephrin-B2 induced cardioprotective effects. Thus, Ephrin-B2 inhibited phenylephrine (PE) induced Nppb expression by 0.775-fold (vs. PE) and hypertrophic growth (0.774-fold reduction of cell size vs. PE). Similar findings were observed in PE-stimulated human cardiac organoids, which showed a 0.58-fold reduction of size in response to Ephrin-B2 treatments compared to PE alone.

Conclusion

Investigating the cross-talk in cardiac hypertrophy reveals novel disturbed communication signatures, with a striking reduction in the intercellular communication pathways of CMs. Reduced expression of receptors of the Ephrin family, particularly Ephrin-B1, in CM may prevent cardioprotective signaling by the agonist Ephrin-B2, which is highly expressed in ECs, leading to inhibition of cardioprotective cross-talk between ECs and CMs in the hypertrophic heart.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Dr. Rolf M. Schwiete StiftungDie Deutsche ForschungsgemeinschaftGerman Center for Cardiovascular Research

Refined prediction and validation of individual risk using machine learning in transcatheter aortic valve implantation: TAVI Risk Machine (TRIM) scores

Background

Given the recent option for treatment using TAVI irrespective of surgical risk, general surgical risk scores have become less relevant, while TAVI-specific scores require refinement. Additionally, post-TAVI risk models are lacking; however, such risk models can support decision between post-TAVI treatment approaches, such as early discharge or close surveillance.

Purpose

This study aimed to predict 30-day mortality following transcatheter aortic valve implantation (TAVI) based on machine learning (ML) using data from the German Aortic Valve Registry.

Methods

Mortality risk was determined using a random forest ML model that was condensed in the newly developed TAVI Risk Machine (TRIM) scores, designed to represent clinically meaningful risk modelling before (TRIMpre) and after (TRIMpost) TAVI. Algorithm was trained and cross-validated on data of 24,452 patients and generalisation was examined on data of 5,889 patients.

Results

TRIMpost demonstrated significantly better performance than traditional scores (C-statistics value, 0.79; 95% confidence interval [CI] [0.74; 0.83]). An abridged TRIMpost score comprising 25 features (calculated using a web interface) exhibited significantly higher performance than traditional scores (C-statistics value, 0.74; 95% CI [0.70; 0.78]).

Conclusion

TRIM scores have high performance for risk estimation before and after TAVI. Together with clinical judgement, they may support standardised and objective decision-making before and after TAVI.

Funding Acknowledgement

Type of funding sources: None.

Clinical outcomes after surgical or transcatheter aortic valve replacement in patients with chronic kidney disease: an analysis in 29 893 patients from the German Aortic Valve Registry

Background

Chronic kidney disease (CKD) is a key risk factor in patients undergoing transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR).

Purpose

We analyzed the impact of eGFR and different stages of chronic kidney disease (CKD), on short- and mid-term survival in patients undergoing TAVI or SAVR.

Methods

Data from 29893 patients enrolled in the German Aortic Valve registry (GARY) from January 2011 to December 2015 receiving TAVI (n=12834) or SAVR (n=17059) at 88 sites were included. The impact of renal impairment, as measured by eGFR and CKD stages, was investigated. The primary endpoint was 1-year cumulative all-cause mortality. A propensity score method was used to compare TAVI vs. SAVR in patients with intermediate risk and mild-to-moderate renal disease being eligible for both therapies.

Results

Higher CKD stages were significantly associated to lower in-hospital, 30-day- and 1-year survival rates. Both TAVI- and SAVR-treated patients in CKD 3a, 3b, 4, and 5 stages showed significant and gradually increasing HR values for 1-year all-cause mortality. The same trend persisted in multivariable analysis, although HR values for CKD 3a and 5 did not reach significance in TAVI patients, whereas CKD 4+5 did not reach statistical significance in SAVR. Likewise, eGFR as a continuous variable was a significant predictor for 1-year mortality, with the best cut-off points being 47.4 mL/min/1.73 m2 for TAVI and 59.8 mL/min/1.73 m2 for SAVR. Significant 8.6% and 9.0% increases in 1-year mortality were observed for every 5-mL reduction in eGFR for TAVI and SAVR, respectively. No significant differences in survival were found between TAVI and SAVR in a matched group of intermediate-risk patients potentially eligible for both therapies (HR [(95% CI] for TAVI vs SAVR 1.24 [0.76, 2.02], p=0.240).

Conclusions

CKD≥3b and CKD≥3a is an independent major risk factor for mortality in patients undergoing TAVI and SAVR, respectively. In the overall population of patients with severe aortic stenosis, an appropriate stratification based on CKD substage may contribute to a better selection of patients suitable for such therapies. TAVI and SAVR appear to achieve similar survival rates in intermediate-risk patients with moderate-to-severe renal dysfunction.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted grants by medical device companies (Edwards Lifesciences, JenaValve Technology, Medtronic, Sorin, St. Jude Medical, Symetis S.A.). Unrestricted support by funding statisticians by the DZHK (Deutsches Zentrum für Herz-Kreislaufforschung).

On the incorporation of iron into hexagonal barium titanate: II. Magnetic moment, electron paramagnetic resonance (EPR) and optical transmission

Systematic measurements of the magnetic moment in dependence on temperature and magnetic field of hexagonal 6H-BaTiO3 + 0.04 BaO + x/2 Fe2O3 (0.005 ⩽ x ⩽ 0.05) ceramics were performed to study the influence of Fe ions on the magnetic properties. While the samples show Curie-Weiss paramagnetism for Fe concentrations ⩽1.0 mol%, antiferromagnetic interactions become manifest for 2.0 and 5.0 mol% iron. With increasing Fe content the antiferromagnetic interaction, which is assumed to be caused by a superexchange mechanism [Formula: see text], becomes stronger. At external magnetic fields smaller than 1 T a further, ferromagnetic interaction between Fe3+ ions is detected below 200 K. The interactions between Fe3+ ions in the samples with 2.0 and 5.0 mol% iron are also manifest in the EPR spectra by numerous lines with low intensity. Q-band EPR investigations of 5.0 mol% Fe doped single crystals confirm the existence of only one type of Fe3+-VO associates in the samples.

Transcatheter aortic valve implantation in nonagenarians: insights from the German Aortic Valve Registry (GARY)

OBJECTIVE

The aim of this study was to compare the outcome of nonagenarians (≥ 90 years) with that of younger (< 90 years) patients undergoing transcatheter aortic valve implantation (TAVI) in current practice.

METHODS

Data are collected from the German Aortic Valve Registry (GARY), which was designed to evaluate current practice in the invasive treatment of patients with aortic valve diseases in Germany. Data were analyzed regarding procedural outcome, 30-day, and 1-year outcomes of nonagenarians in comparison to that of younger patients.

RESULTS

Between 2011 and 2015, 2436/33,051 (7.3%) nonagenarians underwent TAVI and were included in GARY. Nonagenarians were significantly more often male (45.2% vs. 40.0%, p < 0.001), frail (38.7% vs. 34.7%, p < 0.001), and had higher EuroSCORE scores than younger patient group (23.2% vs. 17.0%). Nonagenarians were significantly less often treated via transapical access (16.3% vs. 22.3%, p < 0.001). Procedure was performed significantly less often in general anesthesia (58.2% vs. 60.7%, p = 0.02) in nonagenarians, while necessity of pacemaker implantation was significantly higher in nonagenarians (27.2% vs. 24.8%, p > 0.001). The incidence of other typical postprocedural complications such as severe bleeding events and vascular complications were comparable between groups. However, 30-day (5.2% vs. 3.9%) and 1-year (22.7% vs. 17.7%) mortality rates were significantly higher among nonagenarians and age ≥ 90 years could be identified as an isolated risk factor for mortality.

CONCLUSION

TAVI is a highly standardized procedure that can be performed safely with high procedural success even in very old patients. Although mortality is significantly higher in these patients-most probably due to the intrinsic higher risk profile of the very old patients-the results are still acceptable. To optimize outcome, especially elderly patients seem to profit from a procedure under local anesthesia or conscious sedation, to minimize the rate of postoperative delirium and the length of stay and to facilitate early mobilization.

P1844Blood erythropoietin independently predicts mid-term survival after post-procedural recovery from transcatheter aortic valve replacement in aortic stenosis: a prospective study

Background

Erythropoietin (EPO) is an independent predictor for survival in chronic heart failure, myocardial infarction and other cardiac disorders. In a prospective observational study, independent prognostic value of EPO levels in patients with symptomatic aortic stenosis undergoing TAVR was investigated.

Methods

All consecutive patients undergoing TAVR in a high-volume centre in a 19-month period were included. A 1-year follow-up was completed. Patients with eGRF <30 mL/min/1.73m2 were excluded. WHO guidelines were used to define anaemia (Hb <12mg/dl for women, <13mg/dl for men). Chronic kidney disease (CKD) stages were used to classify eGFR: CKD 1 (>90), 2 (60–90), 3a (45–59), 3b (30–44).

Pre-procedural anaemia status, EPO levels and iron deficiency were compared in 1-year survivors vs. non-survivors. Log-EPO levels were used for a univariate Cox regression analysis of 1-year mortality. Baseline variables considered to be clinically relevant or found significant in univariate analysis were included in multivariate analysis. Kaplan-Meier curves were constructed for patients in each EPO quartile.

Results

185 patients with complete data were included in analyses. Mean age was 81.8 years, 58.4% were male, and 72.4% had NYHA III/IV. Baseline anaemia was present in 51.4% and iron deficiency in 49.2%. Median ferritin was 149.5 (16–1995) μg/L, mean transferrin saturation index was 150±46.7% and median EPO was 13.8 (2.7–231.6) mU/mL.

Thirty-day and 1-year mortality were 3.8%, and 18.9%. Baseline anaemia was significantly associated to 1-year mortality: 29.5% vs 7.8%, p=0.001. Iron deficiency had no impact on mortality (18.1% vs 19.8%, p=ns). At 1 year, pre-procedural EPO levels in non-survivors were significantly higher than in survivors: median 20.30 (6.1–231.6) vs 12.9 (2.7–136) mU/mL; p=0.001.

Higher log-EPO levels predicted 1-year mortality in univariate analysis (HR 6.1, 95% CI 2.5–14.9, p=0.0001). Other significant univariate predictors were pre-procedural anaemia (HR 4.2, 95% CI 1.8–9.7, p=0.001), eGFR, EuroSCORE II, body mass index, and previous atrial fibrillation. A multivariate analysis of EPO after adjusting for such factors was also significant (HR 3.1, 95% CI 1.06–8.9, p=0.039). Kaplan-Meier analyses showed early diverging curves for anaemia vs non-anaemia, whereas the curves for patients in various EPO level quartiles started to diverge at about 100 days after the intervention, with differences consistently increasing during the whole follow-up period. Curve slopes were increasingly higher in successively higher quartiles (figure).

1-year Kaplan-Meier for EPO and anemia

Conclusion

Differently from anaemia, a strong predictor for both early and late mortality after TAVR, high pre-procedural EPO levels were an independent predictor for mid-term mortality, with its predictive value only emerging after post-procedural recovery was completed. EPO predictive value was independent from anaemia or renal dysfunction.

P1850Usefulness and predictive value of the prognostic nutritional index compared to other commonly-used nutritional indexes as a prognostic nutritional marker for short- and mid-term survival after TAVR

Background

Several nutritional indexes predict clinical outcomes after trans-catheter aortic valve replacement (TAVR). The Prognostic Nutritional Index (PNI) is based on serum albumin and lymphocyte count, which makes it a highly practical tool to assess nutritional status. Prognostic value of PNI has been shown in some heart diseases and interventions. Usefulness and predictive value of PNI were investigated in patients with symptomatic aortic stenosis undergoing TAVR. PNI was compared with other commonly-used nutritional indexes that predict survival after TAVR.

Methods

A prospective observational study was carried out in a cohort of 114 patients with aortic stenosis undergoing TAVR in a high-volume centre from 09/2016 to 02/2018. Pre-procedural characteristics and laboratory parameters were measured, and a 1-year follow-up was completed.

PNI was estimated with the formula: (10 × serum albumin [g/dl]) + (0.005 × total lymphocytes [1,000/μl]). Baseline clinical features and 1-year survival were compared in patients with PNI values above vs below median.

A multivariate Cox regression analysis was used to assess the independent predictive value of PNI, for 1-year mortality after TAVR. Kaplan-Meier curves were constructed for patients with PNI above vs below median value. ROC curves were created to assess discrimination ability of PNI, and to compare its AUC values with those for other common nutritional markers, such as Geriatric Nutritional Risk Index (GNRI) and body mass index (BMI).

Results

Mean age was 82.2 years and 59.6% of patients were female. Mean PNI was 46±5. No differences were found in pre-procedural clinical characteristics between patients with PNI values above vs below median.

One-year mortality was significantly higher in patients with PNI values below median (19/23) than in patients with higher PNI values (4/23) (p<0.001). No differences were found in complications according to Valve Academic Research Consortium Criteria-2.

Lower PNI values significantly predicted a lower 1-year survival, even after adjusting for all clinical factors showing significant differences in a univariate analysis (model 1: HR 0.8, 95% CI 0.7–0.9, p<0.0001). Significance persisted also after adjusting for relevant laboratory factors (NT-proBNP, hs-Troponin, CRP, eGFR, cystatin, haemoglobin) (model 2: HR 0.8, 95% CI 0.7–0.9, p<0.05). Kaplan-Meier curves started to diverge soon after the intervention (figure). ROC curves revealed a stronger predictive value for PNI (AUC 0.80) compared to GNRI (0.77) and BMI (0.6) (figure).

Kaplan-Meier curve for PNI and ROC curve

Conclusion

PNI is a useful and practical nutritional marker predicting 1-year survival after TAVR in aortic stenosis. It appears to reflect malnutrition and inflammation prior to the intervention, and to have an impact on prognosis. PNI seems to be a better prognostic marker than BMI or GNRI after TAVR.

Early changes in N-terminal pro-B-type natriuretic peptide levels after transcatheter aortic valve replacement and its impact on long-term mortality

BACKGROUND

N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) levels correlate with higher peri-procedural mortality after transcatheter aortic valve replacement (TAVR). The long-term prognostic value of NT-proBNP within the first days after TAVR, however, remains unclear. This study examined early changes in NT-proBNP prior to and within 6 days after TAVR, the diagnostic value of this biomarker regarding aortic regurgitation (AR), and its prognostic value regarding one-year mortality.

METHODS AND RESULTS

NT-proBNP concentrations were measured in 504 consecutive patients undergoing transapical (TA) or transfemoral (TF) TAVR before and directly after TAVR as well as 4 h and 1, 2, 3, and 6 days after TAVR. The follow-up period was 1 year. NT-proBNP was elevated in all patients at baseline (median 2141 ng/L [IQR 1021-5319 ng/L]). NT-proBNP changes in the first 6 days after TAVR showed significant differences depending on the approach, with a greater and more prolonged rise evident in TA-TAVR patients. NT-proBNP was an independent predictor of mortality in TA patients with AR, with an AUC of 0.794 (95% CI 0.663-0.925; P = 0.003) when measured on day 3 after TAVR. For TF patients with AR and reduced left ventricular systolic function, the AUC for prediction of mortality was 0.897 (95% CI 0.778-1.0; P = 0.004) on day 2.

CONCLUSIONS

The prognostic information of early post-procedural NT-proBNP concentrations is superior to pre-procedural values regarding all-cause mortality within 1 year. Post-procedural NT-proBNP must be interpreted in relation to the TAVR approach. NT-proBNP predicts mortality in TF-TAVR patients with AR and reduced left ventricular function.

Scaffolds in a shell-a new approach combining one-photon and two-photon polymerization

We report on a laser system combining one-photon and two-photon polymerization for precise and fast fabrication of macroscopic three-dimensional structures featuring microscale and nanoscale characteristics. This single-stage process significantly reduces the production time as demonstrated by scaffolds in a shell application. Porous scaffolds with different pore sizes are surrounded by a ring so that cells can be seeded directly to the scaffolds kept in a shell and do not spread over the whole substrate expecting a saving of cell suspension, faster growth on the scaffolds, and a more controllable environment. Compared to a two-photon polymerization process, the ring is fabricated about 500 times faster using one-photon polymerization. The presented hybrid process qualifies for further applications illustrated by a fluidic system.

Self-consistent absorption correction for quantifying very noisy X-ray maps: group III nitride nanowires as an example

Energy-dispersive X-ray mapping in a scanning transmission electron microscope is a method to visualize the spatial distribution of chemical elements in a sample. Quantification of the signal intensities depends on proper background elimination and correction of the self-absorption and fluorescence of X-ray lines in the sample. The latter become particularly relevant for slightly thicker and rough samples, small take-off angles and low-energetic X-ray lines, for which we have recently introduced a self-consistent absorption correction based on effective k*-factors selected automatically from curves simulated as function of a K/L line intensity ratio of one of the heavier elements in the sample for ranges of different compositions. This has been shown to work well for thick and for rough samples. Correcting the background intensity to sub-pixel accuracy is necessary for reliable quantification of very noisy maps. In this study, we show how this self-consistent absorption correction method can be applied to InGaN and AlGaN layers in GaN nanowires, the net maps of which can be so noisy the layers can hardly be seen by the eye (a few counts per pixel) and the background is below a single count in each spectrum channel. The result indicates that background estimation for the Ga L-line intensity using fractional counts from an interpolation of maps from neighbouring X-ray lines of elements that are not actually present in the specimen is critical for quantification. The nanowires studied were between 66 and 375 nm thick.

LAY DESCRIPTION

Energy-dispersive X-ray mapping in a scanning transmission electron microscope is a method to visualize the spatial distribution of chemical elements in a sample. Quantification of the signal intensities depends on proper background elimination and correction of the self-absorption of X-ray lines in the sample. Here we show that our previously developed method of self-consistent effective absorption factors works well even with extremely noise elemental maps of a few net counts only where the human eye can hardly discern any pattern and the background signal is typically less than a single count in each spectrum channel. Correcting the background intensity to sub-pixel accuracy is then necessary for reliable quantification.

Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy

Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of ^{252,253,254}No, and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton density distribution in ^{252,254}No isotopes. Finally, the hyperfine splitting of ^{253}No was evaluated, enabling a complementary measure of its (quadrupole) deformation, as well as an insight into the neutron single-particle wave function via the nuclear spin and magnetic moment.

Improved signal recovery for flow cytometry based on 'spatially modulated emission'

Recently, the technique of 'spatially modulated emission' has been introduced (Baßler et al 2008 US Patent 0080181827A1; Kiesel et al 2009 Appl. Phys. Lett. 94 041107; Kiesel et al 2011 Cytometry A 79A 317-24) improving the signal-to-noise ratio (SNR) for detecting bio-particles in the field of flow cytometry. Based on this concept, we developed two advanced signal processing methods which further enhance the SNR and selectivity for cell detection. The improvements are achieved by adapting digital filtering methods from RADAR technology and mainly address inherent offset elimination, increased signal dynamics and moreover reduction of erroneous detections due to processing artifacts. We present a comprehensive theory on SNR gain and provide experimental results of our concepts.