Transcatheter aortic valve implantation in Germany

Short-Term Changes in Arterial Stiffness Measured by 2D Speckle Tracking in Patients Undergoing Transcatheter Aortic Valve Implantation

Arterial stiffness has received increasing interest as a cardiovascular marker in patients with aortic valve stenosis (AS). So far, studies on the impact of aortic valve replacement (AVR) on arterial stiffness have been equivocal. Two-dimensional speckle tracking (2DST) is a novel, non-invasive method to measure the motion of the vessel wall. In this prospective observational study, we aimed to assess the change in arterial stiffness of the common carotid artery (CCA) measured by 2DST in patients undergoing transcatheter aortic valve implantation (TAVI). A total of 47 patients were included in the study (age 80.04 ± 6.065 years). Peak circumferential strain (CS) was significantly improved after TAVI (4.50 ± 2.292 vs. 5.12 ± 2.958, p = 0.012), as was the peak strain rate (CSR) (0.85 ± 0.567 vs. 1.35 ± 0.710, p = 0.002). Body mass index (BMI), mean arterial pressure (MAP) and hemodynamic parameters were associated with this change. 2DST results did not correlate with aortic pulse wave velocity (aPWV) or augmentation index normalized to heart rate (AIx@75), suggesting a distinct difference between arterial stiffness of the CCA and other stiffness parameters. 2DST seems to be a promising new tool to assess arterial stiffness in TAVI patients.

Cost-Effectiveness of SAPIEN 3 Transcatheter Aortic Valve Implantation Versus Surgical Aortic Valve Replacement in German Severe Aortic Stenosis Patients at Low Surgical Mortality Risk

INTRODUCTION

In the randomized PARTNER 3 trial, transcatheter aortic valve implantation (TAVI) with the SAPIEN 3 device significantly reduced a composite of all-cause death, stroke, and rehospitalization, compared with surgical aortic valve replacement (SAVR), in patients with severe symptomatic aortic stenosis and low risk of surgical mortality. Furthermore, TAVI has been shown to be cost-effective in low-risk patients, compared with SAVR, in a number of countries. This study aimed to determine the cost-effectiveness of TAVI with SAPIEN 3 versus SAVR in Germany.

METHODS

A previously published two-stage Markov-based model that captured clinical outcomes from the PARTNER 3 trial was adapted for the German context using the German Statutory Health Insurance perspective. The model had a lifetime horizon. The cost-utility analysis estimated changes in direct healthcare costs as well as survival and health-related quality of life using TAVI with SAPIEN 3 compared with SAVR.

RESULTS

TAVI with SAPIEN 3 increased quality-adjusted life years (QALYs) by + 0.72 at an increased cost of €8664 per patient. The incremental cost-effectiveness/QALY ratio was €12,037, which fell below that of other cardiovascular interventions in use in Germany. The cost-effectiveness of TAVI over SAVR remained robust across multiple challenging scenarios and was driven by lower longer-term management costs compared with SAVR.

CONCLUSIONS

TAVI with SAPIEN 3 appears to be a clinically meaningful, cost-effective treatment option over SAVR for patients with severe symptomatic aortic stenosis and low risk for surgical mortality in Germany.

CLINICAL TRIAL REGISTRATION NUMBER

www.

CLINICALTRIALS

gov identifier: NCT02675114.

Microcirculatory tissue oxygenation correlates with kidney function after transcatheter aortic valve implantation-Results from a prospective observational study

Introduction

Kidney dysfunction is common in patients with aortic stenosis (AS) and correction of the aortic valve by transcatheter aortic valve implantation (TAVI) often affects kidney function. This may be due to microcirculatory changes.

Methods

We evaluated skin microcirculation with a hyperspectral imaging (HSI) system, and compared tissue oxygenation (StO₂), near-infrared perfusion index (NIR), tissue hemoglobin index (THI) and tissue water index (TWI) in 40 patients undergoing TAVI versus 20 control patients. HSI parameters were measured before TAVI (t1), directly after TAVI (t2), and on postinterventional day 3 (t3). The primary outcome was the correlation of tissue oxygenation (StO₂) to the creatinine level after TAVI.

Results

We performed 116 HSI image recordings in patients undergoing TAVI for the treatment of severe aortic stenosis and 20 HSI image recordings in control patients. Patients with AS had a lower THI at the palm (p = 0.034) and a higher TWI at the fingertips (p = 0.003) in comparison to control patients. TAVI led to an increase of TWI, but had no uniform enduring effect on StO₂ and THI. Tissue oxygenation StO₂ at both measurement sites correlated negatively with creatinine levels after TAVI at t2 (palm: ρ = -0.415; p = 0.009; fingertip: ρ = -0.519; p < 0.001) and t3 (palm: ρ = -0.427; p = 0.008; fingertip: ρ = -0.398; p = 0.013). Patients with higher THI at t3 reported higher physical capacity and general health scores 120 days after TAVI.

Conclusion

HSI is a promising technique for periinterventional monitoring of tissue oxygenation and microcirculatory perfusion quality, which are related to kidney function, physical capacity, and clinical outcomes after TAVI.

Clinical trial registration

https://drks.de/search/de/trial, identifier DRKS00024765.

Artificial Intelligence-Based Spiral CT 3D Reconstruction in Transcatheter Aortic Valve Implantation

To evaluate the clinical application effect of spiral computed tomography (CT) three-dimensional (3D) reconstruction based on artificial intelligence in transcatheter aortic valve implantation (TAVI), a CT 3D reconstruction model based on deep convolutional neural networks (DCNN) was established in this research, which was compared with the model-based iterative reconstruction (MBIR) and used in clinical practice. Then, 62 patients with aortic stenosis (AS) who underwent TAVI surgery were recruited as the research objects. The accuracy, sensitivity, and specificity of the multislice spiral CT scan (MSCT) and transthoracic echocardiography (TTE) in predicting the type of TAVI surgical valve were compared and analyzed. The results showed that the mean absolute error (MAE) (0.01) and root mean square error (RMSE) (0.086) of the MBIR model were higher than the reconstruction model in this research. The structural similarity (SSIM) (0.831) and peak signal-to noise ratio (PSNR) (32.77 dB) of the MBIR model were lower than the reconstruction model, and the differences were considerable ( $P<0.05$ ). Of the valve models selected based on the TTE measurement results, 35 cases were accurately predicted and 27 cases were incorrectly predicted. The accuracy of MSCT was 87.1%, the specificity was 98.84%, and the sensitivity was 92.87%; all of which were significantly higher than TTE ( $P<0.05$ ). In summary, compared with the MBIR reconstruction model, the imaging results of the model established in this research were closer to the real image. Compared with TTE, MSCT had higher accuracy, sensitivity, and specificity and can provide more accurate preoperative predictions for patients undergoing TAVI surgery.

Machine learning-based risk prediction of intrahospital clinical outcomes in patients undergoing TAVI

BACKGROUND

Currently, patient selection in TAVI is based upon a multidisciplinary heart team assessment of patient comorbidities and surgical risk stratification. In an era of increasing need for precision medicine and quickly expanding TAVI indications, machine learning has shown promise in making accurate predictions of clinical outcomes. This study aims to predict different intrahospital clinical outcomes in patients undergoing TAVI using a machine learning-based approach. The main clinical outcomes include all-cause mortality, stroke, major vascular complications, paravalvular leakage, and new pacemaker implantations.

METHODS AND RESULTS

The dataset consists of 451 consecutive patients undergoing elective TAVI between February 2014 and June 2016. The applied machine learning methods were neural networks, support vector machines, and random forests. Their performance was evaluated using five-fold nested cross-validation. Considering all 83 features, the performance of all machine learning models in predicting all-cause intrahospital mortality (AUC 0.94-0.97) was significantly higher than both the STS risk score (AUC 0.64), the STS/ACC TAVR score (AUC 0.65), and all machine learning models using baseline characteristics only (AUC 0.72-0.82). Using an extreme boosting gradient, baseline troponin T was found to be the most important feature among all input variables. Overall, after feature selection, there was a slightly inferior performance. Stroke, major vascular complications, paravalvular leakage, and new pacemaker implantations could not be accurately predicted.

CONCLUSIONS

Machine learning has the potential to improve patient selection and risk management of interventional cardiovascular procedures, as it is capable of making superior predictions compared to current logistic risk scores.

Expert consensus document on the assessment of the severity of aortic valve stenosis by echocardiography to provide diagnostic conclusiveness by standardized verifiable documentation

According to recent recommendations on echocardiographic assessment of aortic valve stenosis direct measurement of transvalvular peak jet velocity, calculation of transvalvular mean gradient from the velocities using the Bernoulli equation and calculation of the effective aortic valve area by continuity equation are the appropriate primary key instruments for grading severity of aortic valve stenosis. It is obvious that no gold standard can be declared for grading the severity of aortic stenosis. Thus, conclusions of the exclusive evaluation of aortic stenosis by Doppler echocardiography seem to be questionable due to the susceptibility to errors caused by methodological limitations, mathematical simplifications and inappropriate documentation. The present paper will address practical issues of echocardiographic documentation to satisfy the needs to analyze different scenarios of aortic stenosis due to various flow conditions and pressure gradients. Transesophageal and multidimensional echocardiography should be implemented for reliable measurement of geometric aortic valve area and of cardiac dimensions at an early stage of the diagnostic procedure to avoid misinterpretation due to inconsistent results.

Transvascular transcatheter aortic valve implantation in 2017

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is emerging as the standard of care for patients with severe aortic stenosis. Recent results have been favourable even for patients with low periprocedural risk.

METHODS

We analysed the number of procedures, complications, and in-hospital mortality rates of all patients undergoing isolated aortic valve replacement in 2017 in Germany, focussing especially on transvascular (TV) TAVI. Patients were stratified according the German Aortic Valve Score (AKL) into the risk classes low, intermediate, high and very high (≥ 10%).

RESULTS

A total of 17,956 TV-TAVI and 9011 isolated surgical aortic valve replacements (iSAVR) were performed in Germany in 2017. Although the total rate of intraprocedural complications after TV-TAVI was the same as in 2016 (both 7.4%), fewer patients experienced an arterial vascular complication in 2017 (2017: 6.0%; 2016: 7.1%; p < 0.001). Likewise, the rate of new pacemaker implantation decreased (2017: 9.6%; 2016:11.4%; p < 0.001). In-hospital mortality after TV-TAVI and iSAVR was equal (2.7%) in 2017, despite the much higher risk profile of TV-TAVI patients. Using the AKL score as reference, TV-TAVI showed a more favourable observed-to-expected mortality (O/E) ratio (0.89) than iSAVR (1.14)- even more pronounced in patients at low risk (0.81 vs. 1.14).

CONCLUSIONS

The rates of major complications like bleeding and permanent pacemaker implantation after TV-TAVI keep declining. In 2017 patients undergoing TV-TAVI had a low in-hospital mortality rate with an O/E ratio < 1, indicating that the results were again better than those of all TAVI and SAVR of the previous year. Overall in-hospital mortality after transvascular TAVI and isolated aortic valve repair 2017 in Germany stratified to risk groups by the German Aortic Valve Score (German AV Score/AKL Score): low risk group (AKL 0- < 3%), intermediate risk group (AKL 3- < 6%), high risk group (AKL 6- < 10%) and very high risk group (AKL ≥ 10%).

Hemodynamics of paradoxical severe aortic stenosis: insight from a pressure-volume loop analysis

BACKGROUND

Controversy exists about the pathophysiology of different hemodynamic subgroups of AS. In particular, the mechanism of the paradoxical low-flow, low-gradient (PLFLG) AS with preserved ejection fraction (EF) is unclear.

METHODS

A total of 41 patients with severe, symptomatic AS were divided into the following 4 subgroups based on the echocardiographically determined hemodynamics: (1) normal-flow, high-gradient (NFHG) AS; (2) low-flow, high-gradient AS; (3) paradoxical low-flow, low-gradient (PLFLG) AS with preserved EF and (4) low-flow, low-gradient (LFLG) AS with reduced EF. As part of the comprehensive invasive examinations, the analyses of the PV loops were performed with the IntraCardiac Analyzer (CD-Leycom, The Netherlands).

RESULTS

PLFLG was characterized by small left ventricular volumes as well as a decreased cardiac index, a decreased systolic contractility and a lower stroke work, than the conventional NFHG AS. Alterations in effective arterial elastance (2.36 ± 0.67 mmHg/ml in NFHG versus 3.01 ± 0.79 mmHg/ml in PLFLG, p = 0.036) and end-systolic elastance (3.72 ± 1.84 mmHg/ml in NFHG versus 5.53 ± 2.3 mmHg/ml in PLFLG, p = 0.040) indicated impaired vascular function and increased chamber stiffness.

CONCLUSIONS

The present study suggests that the hemodynamics of PLFLG AS can be explained by two mechanisms: (1) stiffness of the small left ventricle with reduced contractility, and (2) increased afterload due to the impairment of vascular function. Both mechanisms have similarities to those of heart failure with preserved EF. This type of remodeling may explain the poor prognosis of PLFLG AS.

Characteristics and outcomes of patients ≤ 75 years who underwent transcatheter aortic valve implantation: insights from the SOURCE 3 Registry

BACKGROUND

Current trials and registries of transcatheter valve implantation (TAVI) mostly include patients older than 75 years. Little is known about younger patients who undergo this treatment. We investigated comorbidities among patients < 75 years old who underwent TAVI in the SAPIEN 3™ European post-approval SOURCE 3 Registry, and analysed outcomes at 30 days and 1 year.

METHODS AND RESULTS

Three age groups of patients were analysed for outcomes and characteristics: < 75 (n = 235), 75-80 (n = 391) and ≥ 80 years (n = 1320). Overall, the mean age was 81.6 ± 6.7 years; transfemoral access was used in 87.1% of patients treated with SAPIEN 3 transcatheter heart valves. The mean logistic EuroSCORE increased according to age group (12.6%, 17.3% and 19.7%, respectively, p < 0.001). Younger patients had a higher incidence of comorbidities, particularly those not included in surgical risk score assessment tools, e.g., severe liver disease, previous radiation therapy, and porcelain aorta. Mortality rates were similar between age groups at 30 days (1.7%, 2.0% and 2.3%, respectively, p = 0.79) and 1 year (14.2%, 9.3% and 13.3%, respectively, p = 0.08). However, sudden cardiac death rates were higher in the < 75 years age group compared with the ≥ 85 years age group (20.7% vs. 4.8%, p = 0.010).

CONCLUSIONS

In current TAVI practice, patients younger than 75 years are a minority (12%). Despite younger age and lower surgical risk scores, this cohort was characterized by comorbidities not accounted for by traditional surgical risk scores. More data are needed for this age group to guide the appropriate decision between surgery and TAVI. CLINICALTRIAL.

GOV NUMBER

NCT02698956.

Clinical and economical impact of the presence of an extended heart team throughout the balloon-expandable transcatheter aortic valve implantation procedure

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is a standard therapy for aortic valve stenosis in patients at intermediate-to-high surgical risk. Previously, TAVI at our site was performed by a minimalist heart team (MHT), comprised of two interventional cardiologists, echocardiography staff and two cardiac catheterization laboratory nurses. After revision of German Federal Joint Committee (G-BA) guidelines in September 2015, the presence of an extended heart team (EHT; including a full cardiac surgical team) became mandatory throughout the TAVI procedure. We aimed to evaluate the impact of the EHT on clinical and economical outcomes.

METHODS

Data was retrospectively extracted from the medical records of patients receiving an Edwards SAPIEN 3 valve at the University Hospital Tübingen, Germany, between 2014 and 2017 and matched with cost data from the national invoice system of hospitals (InEK). For comparison, patients were grouped according to whether they underwent TAVI with or without the EHT.

RESULTS

Overall, data for 341 patients (MHT 233; EHT 118) were analysed. Baseline characteristics were largely similar between groups (mean age 81.0 years; 54.5% female), though EHT patients had a lower mean logEuroSCORE (17.5% vs. 19.8%; p = 0.011) and more prior PCI/stenting (39.0% vs. 26.9%; p = 0.022). The rate of immediate procedural death (1.7%) was comparable between groups, as was mortality at 30 days (4.2%). Overall, 1.2% of patients required conversion to surgery. The cost of the index hospitalisation (minus the prosthesis) was higher in the EHT condition (difference + €1604), largely driven by expenditure on physicians (difference + €581; p < 0.001), medical technicians (difference + €372; p < 0.001) and medical supplies (difference +€244; p = 0.001).

CONCLUSION

At our site, the presence of an EHT throughout the TAVI procedure appears to substantially increase hospital expenditure without significantly improving patient outcomes. We suggest that TAVI by a minimalist HT with a surgical team on call in case of emergency may be sufficient.