Coronary Artery Disease in Patients Undergoing Transvalvular Aortic Valve Implantation.

Coronary artery disease (CAD) is common in patients with severe aortic stenosis. With the advent of transcatheter aortic valve implantation (TAVI) as a therapeutic option, management of CAD in such patients has undergone a revolution. Younger patients are now candidates for treatment, and have a greater life-time probability of requiring post-TAVI coronary access. Considerations include pre-procedural assessment and revascularisation, procedural planning to avoid coronary obstruction as well as optimisation of post-procedural coronary access. The authors review the challenges of managing CAD in TAVI patients, shed light on the evidence base, and provide guidance on how to optimise management.

Long-term Prognosis in Patients With Concomitant Acute Coronary Syndrome and Aortic Stenosis.

BACKGROUND: Aortic stenosis (AS) and acute coronary syndrome (ACS) share similar cardiovascular risk factors. The incidence of concomitant AS and ACS is increasing with aging population, yet studies investigating the prognosis of these patients remain scarce. METHODS: This retrospective single-centre cohort study examined consecutive patients who presented with ACS and AS from January 1, 2011, to March 31, 2021. The cohort was divided into mild, moderate, and severe AS based on the index echocardiogram. The primary outcome was all-cause mortality. RESULTS: Of 563 patients, 264 (46.9%) had mild, 193 (34.3%) moderate, and 106 (18.8%) severe AS. The mean follow-up duration was 2.5 years. All-cause mortality was higher among patients with moderate and severe AS compared with mild AS within 30 days (17.0% vs 13.0% vs 6.4%, respectively; P = 0.005) and in the long term (49.7% vs 51.4% vs 35.6%; P = 0.002). Concomitant moderate (hazard ratio [HR] 1.453, 95% confidence interval [CI] 1.020-2.068; P = 0.038) or severe AS (HR 1.873, 95% CI 1.176-2.982; P = 0.008) was an independent predictor of all-cause mortality. Kaplan-Meier curves demonstrated higher mortality in patients with moderate and severe AS compared with mild AS (P < 0.001). Similar survival trends were observed regardless of ACS type and in those with preserved left ventricular ejection fraction. Patients with reduced left ventricular ejection fraction had poor prognosis regardless of AS severity. CONCLUSIONS: ACS patients with concomitant moderate or severe AS have similar high long-term mortality, regardless of ACS type. The high early mortality in moderate and severe AS emphasises the imperative to attempt to mitigate this risk urgently.

A percutaneous approach to create tricuspid regurgitation in swine: a model for transcatheter tricuspid valve therapy assessment.

PURPOSE: The purpose of this study was to develop a simple and effective percutaneous approach to create tricuspid regurgitation in swine. METHODS: Eleven pigs (71.68 ± 7.70 kg, 3 male) were involved in this study. A grasping forceps was introduced into the right ventricle through a steerable sheath under fluoroscopic guidance and used to disrupt the tricuspid valve apparatus by avulsing leaflet or chordae tendineae repeatedly. Transthoracic echocardiography and right ventricular angiography were used to evaluate the degree of tricuspid regurgitation created. RESULTS: Ten of the 11 pigs (90.91%) achieved severe tricuspid regurgitation and 1 (9.09%) obtained moderate tricuspid regurgitation immediately after the procedure. Heart rate of the pigs significantly increased immediately after tricuspid regurgitation creation compared to baseline (88.64 ± 23.24 vs. 76.00 ± 15.30 bpm, P = 0.02), but recovered to normal level at one month follow-up (77.09 ± 11.97 bpm, P = 0.85). The right atrium, tricuspid valve annulus, and right ventricle dilated obviously one month after tricuspid regurgitation creation (dimension changes: 3.01 ± 0.35 vs. 3.56 ± 0.40 cm, P = 0.02; 2.92 ± 0.36 vs. 3.37 ± 0.39 cm, P = 0.01; 3.06 ± 0.42 vs. 3.60 ± 0.47 cm, P = 0.03 respectively). Autopsy findings showed that rupture of leaflet and/or chordae tendineae finally led to the tricuspid regurgitation. CONCLUSIONS: Severe tricuspid regurgitation can be created by a simple and effective percutaneous approach with a grasping forceps in swine model and right heart dilation can be observed consistently at one-month follow-up. This model will be valuable in pre-clinical studies for developing new tricuspid valve repair or replacement technique to treat severe tricuspid regurgitation.

Design Variation, Implantation, and Outcome of Transcatheter Mitral Valve Prosthesis: A Comprehensive Review.

The transcatheter mitral valve prosthesis is ideally suited for patients with inoperable mitral etiology. The transcatheter mitral valve implantation (TMVI) procedure has closely followed the evolution of transcatheter aortic procedures. There are considerable design variations amongst the limited TMVI prostheses currently available, and the implantation profiles of the devices are notably different. This comprehensive review will provide an overview of the current clinically tried TMVI devices with a focused outcome analysis. In addition, we have discussed the various design characteristics of TMVI and its associated failure mode, implantation technology, delivery methods, first-in-man trials, and pivotal trial summary for the synthesis of recent evidence. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021255241, identifier: CRD42021255241.

Cost-Effectiveness of Transcatheter Aortic Valve Implantation in Intermediate and Low Risk Severe Aortic Stenosis Patients in Singapore.

INTRODUCTION: Singapore has the world's second most efficient healthcare system while costing less than 5% GDP. It remains unclear whether transcatheter aortic valve implantation (TAVI) is cost-effective for treating intermediate-low risk severe aortic stenosis (AS) patients in a highly efficient healthcare system. MATERIALS AND METHODS: A two-phase economic model combining decision tree and Markov model was developed to assess the costs, effectiveness, and the incremental cost-effectiveness ratio (ICER) of transfemoral (TF) TAVI versus surgical aortic valve replacement (SAVR) in intermediate-low risk patients over an 8-year time horizon. Mortality and complications rates were based on PARTNER 2 trial cohort A and Singapore life table. Costs were mainly retrieved from Singapore National University Health System database. Health utility data were obtained from Singapore population based on the EuroQol-5D (EQ-5D). A variety of sensitivity analyses were conducted. RESULTS: In base case scenario, the incremental effectiveness of TF-TAVI versus SAVR was 0.19 QALYs. The ICER of TF-TAVI was S$33,833/QALY. When time horizon was reduced to 5 years, the ICER was S$60,825/QALY; when event rates from the propensity analysis was used, the ICER was S$21,732/QALY and S$44,598/QALY over 8-year and 5-year time horizons, respectively. At a willingness to pay threshold of S$73,167/QALY, TF-TAVI had a 98.19% probability of being cost-effective after 100,000 simulations. The model was the most sensitive to the costs of TF-TAVI procedure. CONCLUSION: TF-TAVI is a highly cost-effective option compared to SAVR for intermediate-low risk severe AS patients from a Singapore healthcare system perspective. Increased procedure experience, reduction in device cost, and technology advance may have further increased the cost-effectiveness of TF-TAVI per scenario analysis.

An in vitro investigation into the hemodynamic effects of orifice geometry and position on left ventricular vortex formation and turbulence intensity.

In a healthy human cardiac system, a large asymmetric clockwise vortex present in the left ventricle (LV) efficiently diverts the filling jet from the mitral annulus to the left ventricular outflow track. However, prior clinical studies have shown that artificial mitral valve replacement can affect the formation of physiological vortex, resulting in overall flow instability in the LV. Lately, the findings from several recent hemodynamic studies seem to suggest that the native D-shaped mitral annulus might be a crucial factor in the development of this physiological flow pattern, with its inherent flow stability and formation of coherent structures within the LV. This study aims to investigate the effect of orifice shape and its position with respect to the posterior wall of the ventricle on vortical formation and turbulence intensity in the LV, by utilizing four separate orifice configurations within an in vitro left heart simulator. Stereo particle image velocimetry experiments were then carried out to characterize the downstream flow field of each configuration. Our findings demonstrate that the generation of the physiological left ventricular vortical flow was not solely dependent upon the orifice shape but rather the subsequent jet-wall interaction. The distance of the orifice geometric center from the left ventricular posterior wall plays a significant role in this jet-wall interaction, and thus, vortical flow dynamics.

Transcatheter aortic valve implantation during the COVID-19 pandemic: Clinical expert opinion and consensus statement for Asia.

OBJECTIVES: The impact of the COVID-19 pandemic on the treatment of patient with aortic valve stenosis is unknown and there is uncertainty on the optimal strategies in managing these patients. METHODS: This study is supported and endorsed by the Asia Pacific Society of Interventional Cardiology. Due to the inability to have face to face discussions during the pandemic, an online survey was performed by inviting key opinion leaders (cardiac surgeon/interventional cardiologist/echocardiologist) in the field of transcatheter aortic valve implantation (TAVI) in Asia to participate. The answers to a series of questions pertaining to the impact of COVID-19 on TAVI were collected and analyzed. These led subsequently to an expert consensus recommendation on the conduct of TAVI during the pandemic. RESULTS: The COVID-19 pandemic had resulted in a 25% (10-80) reduction of case volume and 53% of operators required triaging to manage their patients with severe aortic stenosis. The two most important parameters used to triage were symptoms and valve area. Periprocedural changes included the introduction of teleconsultation, preprocedure COVID-19 testing, optimization of protests, and catheterization laboratory set up. In addition, length of stay was reduced from a mean of 4.4 to 4 days. CONCLUSION: The COVID-19 pandemic has impacted on the delivery of TAVI services to patients in Asia. This expert recommendation on best practices may be a useful guide to help TAVI teams during this period until a COVID-19 vaccine becomes widely available.

Hybrid technique to bail out an unsuccessful transfemoral TAVR attempt.

The most common route to perform transcatheter aortic valve replacement (TAVR) is via the transfemoral access. The success of this technique hinges on the successful passage of guidewires across the stenosed aortic valve. Although this is possible in the majority of cases, this case illustrates an occasional anomaly. In this report, we describe a novel hybrid technique involving a transseptal access as well as the formation of a continuous arteriovenous loop to complete the procedure successfully. This technique also has an additional advantage as it maintains the feasibility of performing the procedure under local anaesthesia and conscious sedation.

Transcatheter aortic valve implantation in Asia.

The use of transcatheter aortic valve implantation (TAVI) to treat severe symptomatic aortic valve stenosis has increased exponentially in the last decade. This rapid expansion was seen predominantly in Western developed nations and has been fuelled by favorable results reported from a plethora of well-publicized randomized controlled trials, large retrospective series and national registries. Now, TAVI has become the standard of care for inoperable patients and an alternative to open surgery in patients who are at intermediate to high risk for open surgery. Notwithstanding these positive results, Asia has been relatively slow to adopt this technology despite a potentially large patient pool. Unique features of Asian medical environments and differences in Asian anatomy affecting TAVI uptake in Asia will be discussed. This article serves to outline the various challenging aspects of disseminating TAVI in Asian countries.

Mid-term study of transcatheter aortic valve implantation in an Asian population with severe aortic stenosis: two-year Valve Academic Research Consortium-2 outcomes.

INTRODUCTION: Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions. METHODS: This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve. RESULTS: Mean age was 76.8 years (61.0% male), mean body surface area 1.6 m2 and mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008). CONCLUSION: Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI.

Transcatheter Aortic Valve Replacement With Early- and New-Generation Devices in Bicuspid Aortic Valve Stenosis.

BACKGROUND: Few studies have evaluated the clinical outcomes of transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic valve stenosis (AS). Particularly, limited data exist comparing the results of TAVR with new-generation devices versus early-generation devices. OBJECTIVES: This study sought to evaluate the clinical outcomes of TAVR for bicuspid AS with early- and new-generation devices. METHODS: The Bicuspid TAVR Registry is an international multicenter study enrolling consecutive patients with bicuspid AS undergoing TAVR between April 2005 and May 2015. RESULTS: Of 301 patients, 199 patients (71.1%) were treated with early-generation devices (Sapien XT [Edwards Lifesciences Corporation, Irvine, California]: n = 87; CoreValve [Medtronic, Minneapolis, Minnesota]: n = 112) and 102 with new-generation devices (Sapien 3 [Edwards Lifesciences Corporation]: n = 91; Lotus [Boston Scientific Corporation, Marlborough, Massachusetts]: n = 11). The mean Society of Thoracic Surgeons score was 4.7 ± 5.2 without significant differences between groups (4.6 ± 5.1 vs. 4.9 ± 5.4; p = 0.57). Overall, all-cause mortality rates were 4.3% at 30 days and 14.4% at 1 year. Moderate or severe paravalvular leak was absent and significantly less frequent with new-generation compared to early-generation devices (0.0% vs. 8.5%; p = 0.002), which resulted in a higher device success rate (92.2% vs. 80.9%; p = 0.01). There were no differences between early- and new-generation devices in stroke (2.5% vs. 2.0%; p > 0.99), life-threatening bleeding (3.5% vs. 2.9%; p > 0.99), major vascular complication (4.5% vs. 2.9%; p = 0.76), stage 2 to 3 acute kidney injury (2.5% vs. 2.9%; p > 0.99), early safety endpoints (15.1% vs. 10.8%; p = 0.30), and 30-day all-cause mortality (4.5% vs. 3.9%; p > 0.99). CONCLUSIONS: The clinical outcomes of TAVR in patients with bicuspid AS were favorable. New-generation devices were associated with less paravalvular leak and, hence, a higher device success rate than early-generation devices. (The Bicuspid Aortic Stenosis Following Transcatheter Aortic Valve Replacement Registry [Bicuspid TAVR]; NCT02394184).

A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns.

Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve) has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation.

Numerical Modeling of Intraventricular Flow during Diastole after Implantation of BMHV.

This work presents a numerical simulation of intraventricular flow after the implantation of a bileaflet mechanical heart valve at the mitral position. The left ventricle was simplified conceptually as a truncated prolate spheroid and its motion was prescribed based on that of a healthy subject. The rigid leaflet rotation was driven by the transmitral flow and hence the leaflet dynamics were solved using fluid-structure interaction approach. The simulation results showed that the bileaflet mechanical heart valve at the mitral position behaved similarly to that at the aortic position. Sudden area expansion near the aortic root initiated a clockwise anterior vortex, and the continuous injection of flow through the orifice resulted in further growth of the anterior vortex during diastole, which dominated the intraventricular flow. This flow feature is beneficial to preserving the flow momentum and redirecting the blood flow towards the aortic valve. To the best of our knowledge, this is the first attempt to numerically model intraventricular flow with the mechanical heart valve incorporated at the mitral position using a fluid-structure interaction approach. This study facilitates future patient-specific studies.

Design considerations and quantitative assessment for the development of percutaneous mitral valve stent.

Percutaneous heart valve replacement is gaining popularity, as more positive reports of satisfactory early clinical experiences are published. However this technique is mostly used for the replacement of pulmonary and aortic valves and less often for the repair and replacement of atrioventricular valves mainly due to their anatomical complexity. While the challenges posed by the complexity of the mitral annulus anatomy cannot be mitigated, it is possible to design mitral stents that could offer good anchorage and support to the valve prosthesis. This paper describes four new Nitinol based mitral valve designs with specific features intended to address migration and paravalvular leaks associated with mitral valve designs. The paper also describes maximum possible crimpability assessment of these mitral stent designs using a crimpability index formulation based on the various stent design parameters. The actual crimpability of the designs was further evaluated using finite element analysis (FEA). Furthermore, fatigue modeling and analysis was also done on these designs. One of the models was then coated with polytetrafluoroethylene (PTFE) with leaflets sutured and put to: (i) leaflet functional tests to check for proper coaptation of the leaflet and regurgitation leakages on a phantom model and (ii) anchorage test where the stented valve was deployed in an explanted pig heart. Simulations results showed that all the stents designs could be crimped to 18F without mechanical failure. Leaflet functional test results showed that the valve leaflets in the fabricated stented valve coapted properly and the regurgitation leakage being within acceptable limits. Deployment of the stented valve in the explanted heart showed that it anchors well in the mitral annulus. Based on these promising results of the one design tested, the other stent models proposed here were also considered to be promising for percutaneous replacement of mitral valves for the treatment of mitral regurgitation, by virtue of their key features as well as effective crimping. These models will be fabricated and put to all the aforementioned tests before being taken for animal trials.

Transcatheter aortic valve implantation: implications for Asian patients.

BACKGROUND: transcatheter aortic valve implantation is now an accepted therapy for patients with severe aortic valve stenosis who are deemed inoperable, and it is a reasonable alternative for patients with high surgical risk. This study assessed the clinical outcomes of this procedure and the implications of transcatheter aortic valve implantation for such patients. METHODS: 14 consecutive patients with severe aortic valve stenosis, who underwent transcatheter aortic valve implantation, were assessed. Baseline clinical characteristics, procedural information, and clinical outcomes and complications were compared at baseline and at follow-up. Thirty-day mortality was also assessed. RESULTS: the mean age of the patients was 81 ± 8 years (35% females). The mean Society of Thoracic Surgeons score was 6.8 ± 3.7. Most patients had chronic kidney disease with an estimated glomerular filtration rate of 44.5 ± 14.9 mL·kg(-1)·min(-1). The mean annulus diameter was 21.9 ± 1.7 mm, and 8 (57%) patients received 23-mm valves. After transcatheter aortic valve implantation, the mean transaortic gradient and aortic valve area improved from 42.9 ± 19.4 to 8.9 ± 3.1 mm Hg (p < 0.001) and 0.7 ± 0.1 to 1.5 ± 0.3 cm(2) (p < 0.001), respectively. The 30-day mortality for this cohort was 7%. CONCLUSION: transcatheter aortic valve implantation can be performed successfully in carefully selected Asian patients. The decision to undertake this procedure should be guided by the surgical team.

Combined off-pump transapical transcatheter aortic valve implantation and minimally invasive direct coronary artery bypass.

Transcatheter aortic valve implantation has been shown to be an effective treatment for severe aortic stenosis in high-risk surgical patients. Many of these patients have significant coexisting coronary artery disease. We report the first case of combined off-pump transapical aortic valve implantation and minimally invasive direct coronary artery bypass via a left mini-thoracotomy in an 82-year-old man with significant comorbidities. This combined procedure is technically feasible and can be performed safely in selected patients with aortic stenosis and left anterior descending artery lesion that is not suitable for percutaneous intervention.

Transatrial transcatheter tricuspid valve-in-valve implantation of balloon expandable bioprosthesis.

Transcatheter valve-in-valve implantation into failing mitral and aortic bioprosthetic valves have been reported. This strategy avoids performing high-risk repeat cardiac surgery in elderly patients with multiple comorbidities. Tricuspid valve-in-valve implantation has not been described. We report a case of failing bioprosthetic tricuspid valve in a 48-year-old woman with carcinoid syndrome. We attempted a transatrial transcatheter approach and we successfully deployed a 26-mm Edwards Sapien balloon expandable bioprosthesis (Edwards Lifesciences, Irvine, CA) into a severely stenotic tricuspid bioprosthesis. This case demonstrates the technical feasibility and safety of this approach. Therefore, tricuspid valve-in-valve implantation may be a viable treatment alternative in carefully selected patients.