C-Reactive Protein to Albumin Ratio offers superior risk prediction in patients undergoing mitral valve edge-to-edge repair: a comparison to established surgical risk scores

Background

The population of patients with relevant mitral regurgitation (MR) who stand to gain optimal benefit from mitral valve transcatheter edge-to-edge repair (TEER) remains to be determined. Prior to TEER, a heart-team approach with interdisciplinary decision-making is mandatory integrating both the patient profile and relevant co-morbidities. In addition, the application of established surgical risk scores is recommended by current guidelines. Whether alternative risk prediction is more suitable for this fragile patient cohort burdened with various co-morbidities has not been examined in detail. A simplified approach may be achieved by using the C-Reactive Protein to Albumin Ratio (CAR), but its value in TEER is unclear.

Methods

This single-center, retrospective study thought to determine long-term prognostic accuracy of different risk scores in patients with relevant MR undergoing TEER. For this analysis, 316 patients with a median follow-up time of 5.81 years were included. The primary outcome measure was defined as all-cause mortality. ROC analysis was conducted for the identification of the optimal CAR threshold, subsequently dichotomizing patients into two groups (CAR ≤0.4 and CAR >0.4) estimating their long-term event rate using the Kaplan-Meier method. In addition, we evaluated the prognostic value of CAR compared to two conventional surgical risk scores (logistic EuroSCORE and Society of Thoracic Surgeons [STS] risk score) using C-Index analysis.

Results

Among 316 high-risk patients undergoing TEER (mean age 75.6±8.2 years, 61.7% male, median logistic EuroSCORE 19.9% [11.7; 31.6], median STS Score 3.8% [2.2; 5.7]), 176 (55.7%) patients had a CAR value ≤0.4. Patients with an elevated CAR (>0.4) predominantly suffered from a higher burden of co-morbidities, such as peripheral artery disease (p=0.001), chronic obstructive pulmonary disease (p=0.044), and chronic kidney disease (p=0.015). Consequently, these patients had significantly higher logistic EuroSCORE and STS Score than patients with CAR ≤0.4 (logistic EuroSCORE p=0.002; STS Score p<0.001). Stratification according to the CAR threshold of 0.4 led to significant differences in the Cumulative Incidence curves (p<0.001). In addition, log-rank test revealed a superior risk stratification of the simplified CAR approach compared to established surgical risk scores (Figure 1). This effect consequently reflects in a higher adjusted C-Index for CAR (0.608) compared to logistic EuroSCORE (0.502; p<0.001) and STS Score (0.498; p<0.001).

Conclusions

Our data provide first evidence that alternative risk prediction using CAR allows for a feasible and easy-to-use risk prediction in a real-word TEER cohort presenting with advanced age, a high proportion of frailty and numerous co-morbidities. Alternative risk prediction in TEER patients should be investigated in more detail as the established surgical risk scores seem to demonstrate limited applicability in patients scheduled for TEER.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University Medical Center Hamburg-Eppendorf, Hamburg, Germany

GPCR-dependent pathways promote nanodomain-specific cAMP signaling in human cardiomyocytes, which is severely remodeled in atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft, German Centre for Cardiovascular Research (DZHK)

Background

Cardiac arrhythmias, such as atrial fibrillation (AF), have been linked to the remodeling of membrane receptors and alterations in cAMP-dependent regulation of calcium handling mechanisms. For instance, decreased L-type calcium channel (LTCC) current density but upregulated ryanodine receptor 2 (RyR2) are major hallmarks of AF. Furthermore, adenosine A2A receptor (A2AR) stimulation increases calcium waves without affecting LTCC and serotonin (5-HT) receptors activation exerts stronger control over myofilaments than over RyR2 function. However, up to date no study has elucidated how the increase on cAMP upon different G-protein-coupled receptors (GPCR) stimulation can lead to different physiological compartmentalized responses. The aim of this study was to investigate the effects of various GPCRs on cAMP levels in different cellular compartments in human atrial myocytes from control patients in sinus rhythm (Ctl), and how these compartmentalized effects are altered in AF. Furthermore, alterations in downstream cAMP level control by phosphodiesterases (PDEs) between patient groups were investigated to further elucidate functional differences.

Methods

Atrial myocytes were isolated from tissues of 66 AF and 80 Ctl patients. Cells were then transduced with adenoviruses (Epac1-camps, pm-Epac1-camps and Epac1-JNC) and cultured for 48 hours to express the Förster-resonance energy transfer (FRET)-based cAMP sensor in the cytosolic, membrane and RyR2 nanodomains, respectively. FRET was then used to measure cAMP in 532 isolated human atrial myocytes. Stimulation with β-adrenergic agonist Isoprenaline (ISO, 100nM) was used and compared with 5-HT (100µM) and A2AR (with CGS, 200nM) stimulation. Additionally, a nonspecific PDE inhibitor (IBMX, 100µM) was applied, as well as PDE3 (Cilostamide, 1µM) and PDE4 (Ro 20-1724, 10µM) specific inhibitors.

Results

A desensitization to β-adrenergic receptor stimulation in AF myocytes was exclusively found in the cytosol, while no difference was seen in neither the RyR2 nor LTCC compartment in AF versus Ctl. Similar effects were observed upon 5-HT stimulation with a significant desensitization in the cytosol, and no difference in the RyR2 compartment. On the contrary, AF myocytes displayed a significantly higher increase in cAMP levels compared to Ctl myocytes in the cytosol upon A2ARs stimulation. Importantly, no effect on cAMP levels was observed in the LTCC compartment after A2ARs or 5-HT stimulation. However, PDE3 inhibition on top of 5-HT stimulation showed a significantly smaller effect on cAMP levels in AF myocytes within the LTCC compartment.

Conclusions

Collectively, our data show that cAMP levels are highly compartmentalized in human atrial myocytes and differentially regulated by different GPCRs. Furthermore, PDEs are to a certain extent responsible for the compartmentalized effects of the different GPCRs.

Procedural outcome and risk prediction in patients with implantable cardioverter-defibrillator (ICD) undergoing transvenous lead extraction: a GALLERY subgroup analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Device complications, such as infection or lead dysfunction necessitating transvenous lead extraction (TLE) are continuously rising amongst patients with indwelling transvenous implantable cardioverter-defibrillator (ICD).

Objectives

Aim of this study was to characterize the procedural outcome and risk factors of patients with indwelling 1- and 2-chamber ICD undergoing TLE.

Methods

We conducted a subgroup analysis of all 1- and 2-chamber ICD patients in the GALLERY (GermAn Laser Lead Extraction RegistrY) database. Predictors for procedural failure and all-cause mortality were assessed.

Results

A total of 854 patients with ICD undergoing TLE were identified, who were younger (62.9±13.8 vs. 70.7±13.0 years; p<0.001), less likely to be female (20.8 vs. 27.1%; p<0.001) and had a higher proportion of patients with coronary artery disease (51.5 vs. 38.6%; p<0.001) and highly reduced ejection fraction (32.0 vs. 23.0%; p>0.001), when compared to non-ICD patients. Leading extraction indication was lead dysfunction (48.0 vs. 21.9%; p<0.001), followed by device-related infection (45.6 vs. 73.0%; p<0.001). There were no differences in overall procedural complications (4.3 vs. 4.3%; p=0.980), clinical success rate (97.9 vs. 97.8%; p=0.861) or procedure-related (0.8 vs. 0.5%; p=0.292) and all-cause mortality (3.4 vs. 3.7%; 0.742) between groups. Multivariate analysis revealed lead age≥10 years (OR:5.75, 95%CI:2.0-16.2; p=0.001) as independent predictor for procedural failure. Systemic infection as extraction indication (OR:9.57, 95%CI:2.2-42.4; p=0.003) and procedural complications (OR:8.0, 95%CI:2.8-23.3; p<0.001) were identified as risk factors for all-cause mortality. Predictors for systemic infection in ICD patients were atrial fibrillation (OR: 2.22, 95%CI: 1.51-3.27; p<0.001), diabetes mellitus (OR: 2.28, 95%CI: 1.59-3.25; p<0.001) and chronic kidney disease (OR: 2.0, 95%CI: 1.39-2.89; p<0.001).

Conclusions

Transvenous lead extraction is safe and efficacious in patients with 1- and 2-chamber ICD. Although lead dysfunction is the leading indication for extraction, systemic device-related infection is the main driver of all-cause mortality for ICD patients undergoing TLE.

Regulation of APD and force by Na+/Ca2+ exchanger in hiPSC-cardiomyocytes

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): BMBF

Introduction

Human induced pluripotent stem cell-derived cardiomyocytes (HiPSC-CM) are an emerging, powerful tool to study human cardiac physiology, pharmacology and toxicology, to model cardiovascular diseases or even to use for cardiac repair. Understanding the similarities and differences between hiPSC-CM and adult human cardiomyocytes is critical for their use. Here we focus on sodium calcium exchanger (NCX) who plays a crucial role in the Ca2+-homeostasis in the mammalian heart. Importantly, alterations in NCX expression in human heart are associated with various cardiac pathologies such as heart failure or arrhythmias. In order to investigate whether hiPSC-CM could serve as model for adult human heart NCX we measured the properties of NCX in hiPSC-CM and human ventricular tissue. Rat ventricular tissue was used for comparison.

Methods

HiPSC-CM were differentiated from a healthy iPSC line and dissociated from engineered heart tissue (EHT). Adult human and rat cardiomyocytes were digested from ventricular samples. We measured NCX current by the whole-cell patch clamp technique at 37 °C. Standard sharp microelectrodes were used to record action potentials (AP). Contractile force in human and rat ventricular samples was measured isometrically. A video-optical contractility test system was used to measure force in EHT. SEA0400 (10 µM) was used to block NCX.

Results

NCX currents could be measured in every hiPSC-CM. The NCX current densities in hiPSC-CM were larger than in human ventricular cardiomyocytes (3.2±0.2 pA/pF n=28 vs. 1.3±0.2 pA/pF n=15, p<0.05), but lower than reported for rat left ventricular cardiomyocytes using the same protocol. SEA0400 shortened APD90 markedly in EHT (264.1±24.9 ms to 191±31.6 ms, n=4) and to a lesser extent in rat ventricular tissue (54.4±3.9 ms to 48.9±4.2 ms, n=7). Shortening in human left ventricular preparations was tiny (320±22.1 ms to 305.5±20.3 ms, n=6) and not different from time-matched controls (TMC). Resting membrane potential, action potential amplitude and upstroke velocity were not affected neither in EHT nor in left ventricular preparations (rat and human). Force was significantly increased by NCX block in rat ventricle (by 31±5.4%, n=18) and EHT (by 20.8±3.9%, n=4), but in human left ventricular preparations there was only a tendency to attenuate spontaneous run-down (-3.7±4.3% n=8 with SEA vs. -6.2±3.7% n=12 in TMC).

Conclusion

HiPSC-CM possess NCX in the physiological range. HiPSC-CM show NCX-effects on APD and force as predicted from rat ventricle and in full accordance with cardiac physiology. Lack of NCX effect in human adult ventricles that had been already reported previously needs further investigations.

Outcomes of patients with severe mitral regurgitation treated with transcatheter mitral valve implantation or medical therapy

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with severe mitral regurgitation (MR) unsuitable for standard therapy (i.e., open-heart surgery and transcatheter edge-to-edge repair [TEER]), often remain on medical therapy (MT) alone. Transcatheter mitral valve implantation (TMVI) may represent an alternative treatment option for these patients.

Purpose

We aimed to investigate differences in anatomical baseline characteristics and echocardiographic outcomes between MR patients unsuitable for standard therapy, that were either treated with TMVI or remained on MT.

Methods

Between 05/2016-02/2021, 121 high-risk patients with severe MR were evaluated for TMVI. Clinical, echocardiographic and functional outcomes between the subgroups of patients treated with TMVI and MT were compared. The primary combined endpoint was all-cause death or heart failure (HF) hospitalization at 1 year. Subgroup analyses were performed to define specific patient subsets favouring either TMVI or MT.

Results

At baseline, there were no differences between the TMVI group (n = 38) and the MT group (n = 44) regarding age (all TMVI vs. MT: 77.0 years [IQR 72.9, 80.1] vs. 79.0 [IQR 76.0, 81.7], p = 0.13), gender (42.1% female vs. 56.8% female, p = 0.27) and estimated surgical risk (EuroSCORE II 4.4% [IQR 2.8, 13.6] vs. 6.4 [IQR 3.4, 10.1], p = 0.72). Patients undergoing TMVI were more frequently treated for secondary MR (68.4%), while primary MR was the most prevalent MR etiology in patients remaining on medical therapy (50.0%). Left ventricular (LV) end-diastolic diameters (LVEDD) were larger and LV ejection fraction (LVEF) was lower in the TMVI group (LVEDD 58.0mm [IQR 51.4, 65.0], LVEF 37.0% [IQR 31.4, 51.2]) compared to the MT group (LVEDD 52.0mm [IQR 46.2, 58.8], LVEF 54.5% [IQR 40.8, 60.0]) (p = 0.02 for LVEDD, p < 0.001 for LVEF). MR was effectively reduced to ≤ mild MR in all patients undergoing TMVI. In the MT group, MR remained severe in 90% of patients after 1 year. The primary composite endpoint occurred numerically more often in the MT group (72.2%) compared to the TMVI group (51.6%, p = 0.061). Regarding the primary endpoint, the subgroups of patients with LVEF 30-49% (HR 0.28 [95%-CI 0.11-0.67], p = 0.004), effective regurgitant orifice area (EROA) <0.4 cm2 (HR 0.30 [95%-CI 0.13-0.71], p = 0.006), tricuspid annular plane systolic excursion (TAPSE) ≥17mm (HR 0.27 [95%-CI 0.11-0.67], p = 0.005) and New York Heart Association functional class III (HR 0.38 [95%-CI 0.18-0.81], p = 0.012) were more likely to benefit from TMVI compared to MT.

Conclusions

In patients with severe MR unsuitable for standard therapy, TMVI represents a reasonable therapeutic alternative yielding effective elimination of MR. While most patients eligible for TMVI suffer from secondary MR, the majority of patients remaining on MT has primary MR. The primary endpoint occurred numerically, yet not statistically, more often in patients on MT. Baseline echocardiography was able to identify subgroups of patients with beneficial outcome after TMVI.