Transcatheter aortic valve replacement with the 34 mm Medtronic Evolut valve

Objectives

To report our experience with the recently introduced 34?mm Evolut transcatheter aortic valve replacement (TAVR) prosthesis.

Background

A larger TAVR prosthesis has become available for the treatment of aortic stenosis (AVS) in larger native aortic annuli (up to 30?mm). Outcomes with this new device are still unreported.

Results

The first 25 transfemoral TAVRs performed by our team with the self-expandable 34?mm Evolut are presented. The majority of patients were male (84%) with a mean age of 81.3?±?5.6 years, a median logistic euro-SCORE of 14.7 (5.4-61.0), and a computed tomography measured mean perimeter-derived aortic annulus diameter of 27.1?±?1.4?mm (min. 25.0–max. 31.2?mm). We implanted one 34?mm Evolut in all patients. Median operative time and radiation time were 68.5 and 12.4?min respectively. To optimise final valve position and haemodynamic performance, at least one complete re-sheathing and re-positioning of the same valve was reported in 33.2%. New permanent pacemaker implantation (PPMI) was necessary in 28.5%. At Receiver Operating Characteristic (ROC) analysis, a minimal diameter of the left ventricular outflow tract <21.9?mm was a significant predictor for PPMI (specificity 82%; sensitivity 83%; p?=?0.005; Area Under the Curve (AUC)?=?0.9). Length of stay in hospital was 9.2?±?5.8 days and no in-hospital death was reported. At discharge, grade 1?+?para-valvular regurgitation was present in 32%, and no regurgitation in the remaining patients. Device success and early safety were 100% and 92% respectively.

Conclusions

TAVR with the 34?mm Evolut prosthesis has shown satisfactory acute outcomes. Although results are consistent with those observed with smaller Evolut prostheses, a trend for a higher PPMI rate has been noticed and could derive from a higher oversizing rate.

     

Regional structure–function relationships in mouse aortic valve tissue

Site-specific biomechanical properties of the aortic valve play an important role in native valve function, and alterations in these properties may reflect mechanisms of degeneration and disease. Small animals such as targeted mutagenesis mice provide a powerful approach to model human valve disease pathogenesis; however, physical mechanical testing in small animals is limited by valve tissue size. Aortic valves are comprised of highly organized extracellular matrix compartmentalized in cusp and annulus regions, which have different functions. The objective of this study was to measure regional mechanical properties of mouse aortic valve tissue using a modified micropipette aspiration technique. Aortic valves were isolated from juvenile, adult and aged adult C57BL/6 wild type mice. Tissue tensile stiffness was determined for annulus and cusp regions using a half-space punch model. Stiffness for the annulus region was significantly higher compared to the cusp region at all stages. Further, aged adult valve tissue had decreased stiffness in both the cusp and annulus. Quantitative histochemical analysis revealed a collagen-rich annulus and a proteoglycan-rich cusp at all stages. In aged adult valves, there was proteoglycan infiltration of the annulus hinge, consistent with the observed mechanical differences over time. These findings indicate that valve tissue biomechanical properties vary in wild type mice in a region-specific and age-related manner. The micropipette aspiration technique provides a promising approach for studies of valve structure and function in small animal models, such as transgenic mouse models of valve disease.     

Trends in patient characteristics and clinical outcome over 8 years of transcatheter aortic valve implantation

Aim

In the evolving field of transcatheter aortic valve implantations (TAVI) we aimed to gain insight into trends in patient and procedural characteristics as well as clinical outcome over an 8?year period in a real-world TAVI population.

Methods

We performed a single-centre retrospective analysis of 1,011 consecutive patients in a prospectively acquired database. We divided the cohort into tertiles of 337 patients; first interval: January 2009–March 2013, second interval: March 2013–March 2015, third interval: March 2015–October 2016.

Results

Over time, a clear shift in patient selection was noticeable towards lower surgical risks including Society of Thoracic Surgeons predicted risk of mortality score and comorbidity. The frequency of transfemoral TAVI increased (from 66.5 to 77.4%, p?=?0.0015). Device success improved (from 62.0 to 91.5%, p?<?0.0001) as did the frequency of symptomatic relief (≥1 New York Heart Association class difference) (from 73.8 to 87.1%, p?=?0.00025). Complication rates decreased, including in-hospital stroke (from 5.0 to 2.1%, p?=?0.033) and pacemaker implantations (from 10.1 to 5.9%, p?=?0.033). Thirty-day mortality decreased (from 11.0 to 2.4%, p?<?0.0001); after adjustment for patient characteristics, a mortality-risk reduction of 72% was observed (adjusted hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.13–0.62). One-year mortality rates decreased (from 23.4 to 11.4%), but this was no longer significant after a landmark point was set at 30 days (mortality from 31 days until 1 year) (adjusted HR: 0.69, 95% CI: 0.41–1.16, p?=?0.16).

Conclusion

A clear shift towards a lower-risk TAVI population and improved clinical outcome was observed over an 8?year period. Survival after TAVI improved impressively, mainly as a consequence of decreased 30-day mortality.

     

Cardiologist and cardiac surgeon view on decision-making in prosthetic aortic valve selection: does profession matter?

Aims

Assess and compare among Dutch cardiothoracic surgeons and cardiologists: opinion on (1) patient involvement, (2) conveying risk in aortic valve selection, and (3) aortic valve preferences.

Methods and results

A survey among 117 cardiothoracic surgeons and cardiologists was conducted. Group responses were compared using the Mann–Whitney U test. Most respondents agreed that patients should be involved in decision-making, with surgeons leaning more toward patient involvement (always: 83 % versus 50 % respectively; p?<?0.01) than cardiologists. Most respondents found that ideally doctors and patients should decide together, with cardiologists leaning more toward taking the lead compared with surgeons (p?<?0.01). Major risks of the therapeutic options were usually discussed with patients, and less common complications to a lesser extent. A wide variation in valve preference was noted with cardiologists leaning more toward mechanical prostheses, while surgeons more often preferred bioprostheses (p?<?0.05).

Conclusion

Patient involvement and conveying risk in aortic valve selection is considered important by cardiologists and cardiothoracic surgeons. The medical profession influences attitude with regard to aortic valve selection and patient involvement, and preference for a valve substitute. The variation in valve preference suggests that in most patients both valve types are suitable and aortic valve selection may benefit from evidence-based informed shared decision-making.     

Allogenic heart valve bank in the Department of Cardiovascular Surgery and Transplantology of Jagiellonian University in Cracow – 23 years experience in the treatment of aortic valve or aortic root diseases.

Allogenic aortic valves are widely used in case of native aortic valve or root disease as well as failed prosthetic valves with great success. At the Department of Cardiovascular Surgery and Transplantology of the Jagiellonian University in Cracow, aortic valve or aortic root replacement with allogenic aortic valve has been performed for 23 years. Allogenic heart valve bank was founded in 1980. In the bank we prepare both aortic allografts for adult cardiac surgical procedures and pulmonary allografts that are mostly used for repair of congenital heart disease.Allogenic aortic valves implantation was usually considered in our clinic for older patients, patients with infective endocarditis of the native or prosthetic valve, young women in reproductive age and patients with Marfan syndrome. Allografts exhibit excellent clinical performance and acceptable durability with no early failure if properly inserted. Between 1980 and 1992, allografts were obtained only from cadavers during routine autopsies. More than 10% of prepared allografts were exported to other cardiac surgery centres in Poland and foreign countries.Aortic valve replacement using allogenic aortic valves can be performed with acceptable mortality and good long-term results. The procedure although surgically more challenging has the advantage of not requiring anticoagulation therapy, hemodynamic performance of the allogenic valve is excellent, it demonstrates freedom from thromboembolism and infective endocarditis. We would like to emphasize the importance and advantages of the fact that allogenic heart valve bank is placed in the department of cardiovascular surgery and it is able to supply the department in heart valve allografts 24 h a day.     

Impact of hyperinsulinemia and hyperglycemia on valvular interstitial cells – A link between aortic heart valve degeneration and type 2 diabetes

Type 2 diabetes is a known risk factor for cardiovascular diseases and is associated with an increased risk to develop aortic heart valve degeneration. Nevertheless, molecular mechanisms leading to the pathogenesis of valve degeneration in the context of diabetes are still not clear. Hence, we hypothesized that classical key factors of type 2 diabetes, hyperinsulinemia and hyperglycemia, may affect signaling, metabolism and degenerative processes of valvular interstitial cells (VIC), the main cell type of heart valves. Therefore, VIC were derived from sheep and were treated with hyperinsulinemia, hyperglycemia and the combination of both. The presence of insulin receptors was shown and insulin led to increased proliferation of the cells, whereas hyperglycemia alone showed no effect. Disturbed insulin response was shown by impaired insulin signaling, i.e. by decreased phosphorylation of Akt/GSK-3α/β pathway. Analysis of glucose transporter expression revealed absence of glucose transporter 4 with glucose transporter 1 being the predominantly expressed transporter. Glucose uptake was not impaired by disturbed insulin response, but was increased by hyperinsulinemia and was decreased by hyperglycemia. Analyses of glycolysis and mitochondrial respiration revealed that VIC react with increased activity to hyperinsulinemia or hyperglycemia, but not to the combination of both. VIC do not show morphological changes and do not acquire an osteogenic phenotype by hyperinsulinemia or hyperglycemia. However, the treatment leads to increased collagen type 1 and decreased α-smooth muscle actin expression. This work implicates a possible role of diabetes in early phases of the degeneration of aortic heart valves.     

Numerical evaluation of transcatheter aortic valve performance during heart beating and its post-deployment fluid–structure interaction analysis

Biomechanics and Modeling in Mechanobiology - Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure that provides an effective alternative to open-heart surgical valve...     

TGF-β mediates early angiogenesis and latent fibrosis in an Emilin1-deficient mouse model of aortic valve disease

Aortic valve disease (AVD) is characterized by elastic fiber fragmentation (EFF), fibrosis and aberrant angiogenesis. Emilin1 is an elastin-binding glycoprotein that regulates elastogenesis and inhibits TGF-β signaling, but the role of Emilin1 in valve tissue is unknown. We tested the hypothesis that Emilin1 deficiency results in AVD, mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β dysregulation. Using histology, immunohistochemistry, electron microscopy, quantitative gene expression analysis, immunoblotting and echocardiography, we examined the effects of Emilin1 deficiency (Emilin1^−/−) in mouse aortic valve tissue. Emilin1 deficiency results in early postnatal cell-matrix defects in aortic valve tissue, including EFF, that progress to latent AVD and premature death. The Emilin1^−/− aortic valve displays early aberrant provisional angiogenesis and late neovascularization. In addition, Emilin1^−/− aortic valves are characterized by early valve interstitial cell activation and proliferation and late myofibroblast-like cell activation and fibrosis. Interestingly, canonical TGF-β signaling (phosphorylated Smad2 and Smad3) is upregulated constitutively from birth to senescence, whereas non-canonical TGF-β signaling (phosphorylated Erk1 and Erk2) progressively increases over time. Emilin1 deficiency recapitulates human fibrotic AVD, and advanced disease is mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β activation. The early manifestation of EFF and aberrant angiogenesis suggests that these processes are crucial intermediate factors involved in disease progression and therefore might provide new therapeutic targets for human AVD.KEY WORDS: Elastic fibers, Extracellular matrix, Aortic valve, Fibrosis, Angiogenesis     

Introducing transcatheter aortic valve implantation with a new generation prosthesis: Institutional learning curve and effects on acute outcomes

Objectives

We present our single-centre experience with the direct flow medical (DFM) trans-catheter aortic valve implantation (TAVI) prosthesis addressing the impact of learning curve upon outcomes.

Background

The DFM has been recently introduced for TAVI. The prosthesis presents original design and implantation features.

Methods

Patients were divided into three groups according to the chronological implantation sequence that reflected technical skills acquisition of the entire team.

Results

Group I included the first 20 patients (early learning phase), group II the second 20 patients (proctoring to other members of the team), and group III the following 93 patients (technique consolidation). Differences in baseline and procedural variables were analysed. Nonparametric correlation and linear regression were used to identify changes according to institutional cumulative experience. There was a significant correlation between catheterisation time and institutional experience (rho = ?0.4; p < 0.0001) confirmed at linear regression (beta = ?0.2; p = 0.001; CI: ?0.3?–??0.08). Moreover, there was lower rate of valve retrieval in group III (15% vs. 20% vs. 10%; p = 0.5). No intra-procedural mortality was reported and improved early safety (at 30 days) was observed (80% vs. 85% vs. 87.1; p = 0.7). At hospital discharge, valve haemodynamic performance was satisfactory with only mild regurgitation in 10% (I), 20% (II), and 9.7% (III) (p = 0.8).

Conclusions

DFM adequate sizing and implantation can be achieved after the early learning phases. A significant reduction in catheterisation time is reported after the first 20 patients. Results remain satisfactory during the proctoring and technical consolidation phase.

     

Thrombosis of Bj?rk-Shiley aortic valve prosthesis: report of three cases.

Thrombotic malfunction of a Björk-Shiley aortic valve prosthesis occurred in three patients 6 to 16 months postoperatively. None of the patients had been taking anticoagulants. Although the presentation was acute, prodromal symptoms could be identified retrospectively in two of the patients. Two patients survived thrombectomy. Postoperative anticoagulant therapy is recommended in patients with these prostheses despite factors that may make such therapy riskier in specific patients. Attention to the character of murmurs and of the closure sound of the prosthetic valve must be part of the routine follow-up. In the emergency situation, when delay must be avoided, catheterization and angiography are unnecessary. The operative approach consists of complete thrombectomy without replacement of the valve or any of its components unless there is obvious periprosthetic leak or prosthetic wear.     

Patient-specific computer modelling – its role in the planning of transcatheter aortic valve implantation

Transcatheter aortic valve implantation is increasingly used to treat patients with severe aortic stenosis who are at increased risk for surgical aortic valve replacement and is projected to be the preferred treatment modality. As patient selection and operator experience have improved, it is hypothesised that device-host interactions will play a more dominant role in outcome. This, in combination with the increasing number of valve types and sizes, confronts the physician with the dilemma to choose the valve that best fits the individual patient. This necessitates the availability of pre-procedural computer simulation that is based upon the integration of the patient-specific anatomy, the physical and (bio)mechanical properties of the valve and recipient anatomy derived from in-vitro experiments. The objective of this paper is to present such a model and illustrate its potential clinical utility via a few case studies.     

Systolic fluid–structure interaction model of the congenitally bicuspid aortic valve: assessment of modelling requirements

A transient fluid–structure interaction (FSI) model of a congenitally bicuspid aortic valve has been developed which allows simultaneous calculation of fluid flow and structural deformation. The valve is modelled during the systolic phase (the stage when blood pressure is elevated within the heart to pump blood to the body). The geometry was simplified to represent the bicuspid aortic valve in two dimensions. A congenital bicuspid valve is compared within the aortic root only and within the aortic arch. Symmetric and asymmetric cusps were simulated, along with differences in mechanical properties. A moving arbitrary Lagrange–Euler mesh was used to allow FSI. The FSI model requires blood flow to induce valve opening and induced strains in the region of 10%. It was determined that bicuspid aortic valve simulations required the inclusion of the ascending aorta and aortic arch. The flow patterns developed were sensitive to cusp asymmetry and differences in mechanical properties. Stiffening of the valve amplified peak velocities, and recirculation which developed in the ascending aorta. Model predictions demonstrate the need to take into account the category, including any existing cusp asymmetry, of a congenital bicuspid aortic valve when simulating its fluid flow and mechanics.     

Comments on: ‘Randomised comparison of a balloon-expandable and self-expandable valve with quantitative assessment of aortic regurgitation using magnetic resonance imaging’

Netherlands Heart Journal -     

Surgical aortic valve replacement in patients older than 75 years: is there really a quality of life benefit?

BackgroundTo evaluate the results of elective isolated surgical aortic valve replacement (SAVR) on quality of life (QoL) in patients > 75 years.Methods138 patients operated between January 2008 and December 2011 were included. The EuroQOL questionnaire (EQ-5D, EQ-VAS) was completed preoperatively, and 1- and 2-years postoperatively. The logistic EuroSCORE was used for risk stratification, the Corpus Christi Heart project criteria to assess physical activity.ResultsMean age was 79.5 ± 2.8 years, mean risk 9.7 ± 5.4, hospital mortality 2.8 %. For 115 patients (83.3 %) the preoperative QoL information was complete. Fifty patients were classified as sedentary. In the first postoperative year 13 patients died, mostly sedentary patients (p = 0.046) with a low EQ-5D (p = 0.017). There was no QoL information on 32 survivors, mostly sedentary patients (p = 0.001). The 70 patients with QoL information showed an increased QoL (NS). Two years postoperatively, 16 patients died, significantly more sedentary patients (p = 0.015) with a low EQ-5D (p = 0.006). For 42 survivors, there was no QoL information; these were mostly sedentary patients (p = 0.021). The 57 patients with 2-year QoL information had an increased EQ-5D (NS) and EQ-VAS (p = 0.024).ConclusionsQoL increases after SAVR. However, the patients lost to follow-up were mostly sedentary or had a low preoperative QoL, which can lead to biased results.     

Reply to the letter of Soliman et al. regarding ‘Randomised comparison of a balloon-expandable and self-expandable valve with quantitative assessment of aortic regurgitation using magnetic resonance imaging’

Netherlands Heart Journal -