Transcatheter aortic valve insertion (TAVI): a review

Computed tomography imaging in preprocedural planning of transcatheter valvular heart interventions

Cardiac Computed Tomography (CCT) has become a reliable imaging modality in cardiology providing robust information on the morphology and structure of the heart with high temporal and isotropic spatial resolution. For the past decade, there has been a paradigm shift in the management of valvular heart disease since previously unfavorable candidates for surgery are now provided with less-invasive interventions. Transcatheter heart valve interventions provide a real alternative to medical and surgical management and are often the only treatment option for valvular heart disease patients. Successful transcatheter valve interventions rely on comprehensive multimodality imaging assessment. CCT is the mainstay imaging technique for preprocedural planning of these interventions. CCT is critical in guiding patient selection, choice of procedural access, device selection, procedural guidance, as well as allowing postprocedural follow-up of complications. This article aims to review the current evidence of the role of CCT in the preprocedural planning of patients undergoing transcatheter valvular interventions.

The development and testing of a smart sensorized guide wire for catheterization in a "blood" vessel phantom to support aortic valve implementation

PURPOSE

Heart valve disease is commonly treated by minimally invasive procedures with guide wires and catheterization. The main purpose of this study is to find out whether an extension of the guide wire with a sensor can support the surgeon within the blood vessel to reduce X-ray necessity.

METHODS

A smart guide wire is developed by an extension with a flex-bending sensor to evaluate the sensor signal with and without "blood" flow at a constant compression force. Various surgically relevant investigations are performed. For assessment, the mean temporal average of the moving averaged filtered ADC signal and a subsequent FFT are carried out.

RESULTS

Results show that there is a smaller sensor signal when the applied force or bending at the sensor is higher. In all investigations, there was a different sensor signal. The flex-bending sensor can detect the effect of pulsatile flow. The smallest temporal averaged signal difference between reference and clamp in the front wire's tip is 1.09%. For example, the mean temporal average of the filtered ADC signal for different clinically relevant scenarios is between 2550 and 2900.

CONCLUSIONS

The results show that the sensorized guide wire developed for catheterization can support aortic valve implementation. The sensor sensitivity is sufficient to detect even very small variations within the blood vessel and therefore is promising to support catheterization heart valve surgeries in future.

A Systematic Review and Statistical Analysis of Factors Influencing the Cost-Effectiveness of Transcatheter Aortic Valve Implantation for Symptomatic Severe Aortic Stenosis

Objective

Transcatheter aortic valve implantation (TAVI) is a disruptive technology recommended for patients with symptomatic severe aortic stenosis (sSAS). Despite being available for over 15 years in Europe, with an extensive volume of clinical and economic evaluations across all surgical risk groups, there is little evidence on the identification of the key drivers of TAVI's cost-effectiveness. This study sought to identify these factors and quantify their role.

Methods

A systematic literature review was conducted to identify published economic evaluations of TAVI. This was supplemented by health technology assessment reports. The primary outcome was the likelihood of TAVI being found cost-effective. Secondary outcomes of TAVI being dominant, and the incremental health benefits of TAVI were also explored.

Results

Forty-two studies, reporting 65 unique analyses, were identified. TAVI was found to be cost-effective and dominant in 74% and 20% of analyses, respectively. The latest generation balloon-expandable TAVI device (SAPIEN 3) was more likely to be found cost-effective, as was TAVI use in low-risk populations and when performed via transfemoral access route. There was heterogeneity in the approach taken to economic modelling, which may also influence estimates of cost-effectiveness. Analyses that found TAVI to be dominant always compared it to surgery and usually considered the latest generation balloon-expandable TAVI device. Largest health benefits were observed for the inoperable risk group.

Conclusion

For patients with sSAS, TAVI is typically a cost-effective treatment option. There are important differences by device generation, risk group and access route. It is crucial to consider these differences when appraising the health economic evidence-base for TAVI.

Prognostic value of biological parameters in patients with severe aortic stenosis undergoing TAVI - results at six months

(1) Background: Aortic stenosis is the most common valvulopathy in elderly patients over 60 years of age. The absence of immediate surgical intervention through classic valve replacement or through a minimally invasive procedure, namely transcatheter implantation of the aortic valve (TAVI) leads to an increase in the risk of morbidity and mortality through the deterioration of the clinical condition. Since the first interventional transcatheter aortic valve implantation procedure was performed in 2012 and until now, the progression of medical technology and state-of-the-art valves have led to the refinement of the treatment strategy and the improvement of the prognosis of patients with aortic stenosis undergoing TAVI in the first 6 months after the procedure; (2) Methods: We conducted a prospective study in which 86 patients diagnosed with severe aortic stenosis underwent minimally invasive valve replacement by TAVI; (3) Results: The presence of preoperative anemia is associated with a negative prognosis both in the medium term and in evolution, and in addition to hematological parameters, we also evaluated a series of biochemical data, with special attention to renal function and lipid profile; (4) Conclusions: Biological parameters followed after TAVI may be predictors associated with a negative long-term prognosis.

Examination of the most cited studies on transcatheter aortic valve replacement with bibliometric analysis

AIM

The aim of this study is to analyze the studies on TAVI with the bibliometric method and to perform a scientiometric analysis of the top 100 most cited articles for researchers.

METHODS

The Thomson Reuters Web of Science database was searched for all relevant articles using the terms "TAVR" and "TAVI". The results were ordered according to the number of citations. We also analyzed the 100 most cited articles (T100) by annual average citation count (ACpY), years, research methods, author, institution, journal, funding agencies, and keywords. Analyses were also performed between the total number of citations, ACpY, impact factors, and publication time.

RESULTS

The article titled "Transcatheter Aortic-Valve Implantation for Aortic Stenosis in Patients Who Cannot Undergo Surgery" was the most cited article (n = 4616). The article titled "Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients" had the highest ACpY count (n = 497). The United States was the country that contributed the most to the T100 list. While the journal that contributed the most with 32 articles was "Journal of the American College Of Cardiology", the journal in which the top 10 most cited articles were published most frequently was the "New England Journal of Medicine". In addition, the most publications were made in 2012.

CONCLUSION

Although this bibliometric analysis study has some limitations, it allows the most cited publications on TAVI to be analyzed systematically and provides scientific contributions.

Immediate aortic dissection after transcatheter aortic valve replacement: A case report and review of the literature

-Aortic dissection of descending aorta was detected by intraoperative TEE in a case of 67-year-old man with symptomatic severe aortic stenosis after TAVR. -Transesophageal echocardiogram after TAVR procedure is helpful to detect this rare complication.

Rapid development of an iatrogenic aortic dissection following transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) represents a catheter-based and minimally invasive replacement of the aortic valve. TAVI is considered to be a relatively safe procedure and has evolved to a standard procedure in inoperable and high-risk patients with aortic stenosis. We present a case of an octogenarian who died in hospital less than a day after an initially satisfactory TAVI. Cardiologists suspected a combination of cardiogenic and hemorrhagic shock as the cause of death. Autopsy showed rupture of an extensive aortic dissection, which had developed within 24 h after the procedure. The cause of death was eventually defined as internal bleeding due to a rapid two-stage vascular process. The manner of death was considered accidental because an iatrogenic vessel injury beyond the aortic arch was causative for the death. This unusual case highlights the potential for rare, but fatal, complications within the scope of cardiac catheterizations, such as TAVI. Additionally, our findings suggest that these complications need to be recognized in the diagnostic process and management of post-interventional complications.

TAVI and the future of aortic valve replacement

Aortic valve stenosis (AS) is the most common valvular pathology and has traditionally been managed using surgical aortic valve replacement (SAVR). A large proportion of affected patient demographics, however, are unfit to undergo major surgery given underlying comorbidities. Since its introduction in 2002, transcatheter aortic valve implantation (TAVI) has gained popularity and transformed the care available to different-risk group patients with severe symptomatic AS. Specific qualifying criteria and refinement of TAVI techniques are fundamental in determining successful outcomes for intervention. Given the successful applicability in high-risk patients, TAVI has been further developed and trialed in intermediate and low-risk patients. Within intermediate-risk patient groups, TAVI was shown to be noninferior to SAVR evaluating 30-d mortality and secondary endpoints such as the risk of bleeding, development of acute kidney injury, and length of admission. The feasibility of expanding TAVI procedures into low-risk patients is still a controversial topic in the literature. A number of trials have recently been published which demonstrate TAVI as noninferior and even superior over SAVR for primary study endpoints.

Description of the aortic root anatomy in relation to transcatheter aortic valve implantation

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) has emerged as a less invasive treatment than surgical aortic valve replacement in patients with aortic stenosis. Understanding the anatomy of aortic valve complex may help in optimal positioning of prosthetic valve and circumvent complications that can arise during its implantation.

MATERIAL AND METHODS

The anatomy of aortic root was studied in 30 formalin-fixed cadavers. Aortic root and left ventricular cavity was opened to measure the diameter at the base of aortic root and sinotubular junction (STJ); distance of coronary ostia from base of aortic root and STJ; height and width of aortic valve leaflets; length and thickness of membranous septum (MS).

RESULTS

The diameter of aorta at the base of aortic root and STJ was 22.4±2.1 mm and 21.8±2.4 mm, respectively. The height of aortic leaflets was smaller than the width. The right and left coronary ostia were 10.7±1.9 mm and 10.5±1.9 mm above the base of aortic root. Membranous septum was 4.7±1.23 mm (range 2.9-6.1 mm) long and formed part of the wall of aortic root in 40% (12/30) cases.

CONCLUSIONS

Low lying coronary ostia speculate the use of a small prosthesis size to avoid or reduce the degree of coronary compression. Length of MS may help in deciding the extent of devise penetration into left ventricular outflow tract to avoid conduction block. Membranous septum forming wall of aortic root increases the risk of aortic root rupture and iatrogenic membranous defect during TAVI.

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.

Updates on transcatheter aortic valve replacement: Techniques, complications, outcome, and prognosis

Transcatheter aortic valve replacement (TAVR) initially emerged as a therapeutic option for high-risk patients with severe aortic stenosis. Advancement in technologies since the first era of TAVRs, experience from previous obstacles, and lessons learned from complications have allowed the evolution of this procedure to the current state. This review focuses on the updates on the most current devices, complications, and outcomes of TAVR.

Correlation between structural changes and acute thrombogenicity in transcatheter pericardium valves after crimping and balloon deployment

INTRODUCTION

Transcathether heart valve replacement has gained considerable acceptance during the last decades. It is now part of the armamentarium for aortic valve replacement. The procedure proved to be highly efficient. However the issues of the blood compatibility and tissue durability were not raised and the adverse events were probably under-reported, according to observations of thrombosis after deployment.

MATERIAL AND METHOD

Bovine pericardium leaflets were sewn inside a 26mm diameter stainless steel stent to manufacture these valves (one control and two experimental). The correlation between the trauma and the acute thombogenicity of bovine pericardium leaflets, after crimping and ballooning, was investigated via an in vitro blood flow with labeled platelets. These leaflets were processed for histology: scanning electron microscopy, light microscopy, and transmission electron microscopy.

RESULTS

The control specimens showed a regular pericardium structure with some blood cells deposited on the collagen fibrous surface (inflow) and scarce blood cells deposited on the serous surface (outflow). After crimping and ballooning, the structure of the pericardium was severely injured, eventually with delaminations and ruptures. The blood cell uptake was considerably increased compared to the control.

CONCLUSION

It would therefore be appropriate to pay more attention to the design of the valves. Specifically, the incorporation of a buffer tissue or fabric between the pericardium and the metallic stent is suggested. The issue of ballooning deserves detailed and in depth investigation regarding the lifetime of the device.

The role of cardiovascular magnetic resonance in the assessment of severe aortic stenosis and in post-procedural evaluation following transcatheter aortic valve implantation and surgical aortic valve replacement

Degenerative aortic stenosis (AS) is the most common valvular disease in the western world with a prevalence expected to double within the next 50 years. International guidelines advocate the use of cardiovascular magnetic resonance (CMR) as an investigative tool, both to guide diagnosis and to direct optimal treatment. CMR is the reference standard for quantifying both left and right ventricular volumes and mass, which is essential to assess the impact of AS upon global cardiac function. Given the ability to image any structure in any plane, CMR offers many other diagnostic strengths including full visualisation of valvular morphology, direct planimetry of orifice area, the quantification of stenotic jets and in particular, accurate quantification of valvular regurgitation. In addition, CMR permits reliable and accurate measurements of the aortic root and arch which can be fundamental to appropriate patient management. There is a growing evidence base to indicate tissue characterisation using CMR provides prognostic information, both in asymptomatic AS patients and those undergoing intervention. Furthermore, a number of current clinical trials will likely raise the importance of CMR in routine patient management. This article will focus on the incremental value of CMR in the assessment of severe AS and the insights it offers following valve replacement.