Adjuncts to transcatheter aortic valve implantation

Introduction: The appreciable rise in percutaneous valve procedures has been pursued by a wave of development in advanced technology to help guide straightforward, streamlined and safe intervention. This review article aims to highlight the adjunctive devices, tools and techniques currently used in transcatheter aortic valve implantation procedures to avoid potential pitfalls.

Areas covered: The software and devices featured here are at the forefront of technological advances, most of which are not yet in widespread use. These products have been discussed in national and international structural intervention conferences and the authors felt it important to showcase particularly well designed adjuncts that improve procedural efficacy and safety. Whilst vascular pre-closure systems are used routinely and are an integral part of these complex cardiovascular procedures, these have been well summarised elsewhere and are beyond the scope of this article.

Expert commentary: The rising volume of patients with aortic stenosis who are treatable with TAVI means that this exponential increase in procedures must be accompanied by a steady decline in procedural complications. This section provides an overview of our current perspective, and what we feel the direction of travel will be.     

Aortic annulus dimension assessment by computed tomography for transcatheter aortic valve implantation: differences between systole and diastole

Accurate assessment of aortic annular dimensions is essential for successful transcatheter aortic valve implantation (TAVI). Annular dimensions are conventionally measured in mid-systole by multidetector computed tomography (MDCT), echocardiography and angiography. Significant differences in systolic and diastolic aortic annular dimensions have been demonstrated in cohorts without aortic stenosis (AS), but it is unknown whether similar dynamic variation in annular dimensions exists in patients with severe calcific AS in whom aortic compliance is likely to be substantially reduced. We investigated the variation in aortic annular dimensions between systole and diastole in patients with severe calcific AS. Patients with severe calcific AS referred for TAVI were evaluated by 128-slice MDCT. Aortic annular diameter was measured during diastole and systole in the modified coronal, modified sagittal, and basal ring planes (maximal, minimal and mean diameters). Differences between systole and diastole were analysed by paired t test. Fifty-nine patients were included in the analysis. Three of the five aortic dimensions measured increased significantly during systole. The largest change was a 0.75 mm (3.4%) mean increase in the minimal diameter of the basal ring during systole (p = 0.004). This corresponds closely to the modified sagittal view, which also increased by mean 0.42 mm (1.9%) during systole (p = 0.008). There was no significant change in the maximal diameter of the basal ring or the modified coronal view during systole (p > 0.05). There is a small magnitude but statistically significant difference in aortic annulus dimensions of patients with severe AS referred for TAVI when measured in diastole and systole. This small difference is unlikely to alter clinical decisions regarding prosthesis size or suitability for TAVI.     

Vascular access in transcatheter aortic valve implantation

The positive early experiences with TAVI however, revealed that vascular access remains a hindrance to broader application and success of the procedure. This article will review the most common vascular routes used to deliver transcatheter aortic valves, and describe a new technique via the right axillary/subclavian artery approach.     

超声心动图用于心尖入路经导管主动脉瓣植入术

目的 评价超声心动图用于心尖入路经导管主动脉瓣植入术(TAVI)的价值.方法 纳入23例接受J-Valve TAVI的主动脉瓣疾病患者,根据主要疾病,将其中20例非重度主动脉瓣狭窄(AS)合并中度以上主动脉瓣反流(AR)者分为AS组(n=10)及AR组(n=10).术前行经胸超声心动图(TTE),术中全程以经食管超声心...     

Development of a risk score for outcome after transcatheter aortic valve implantation

Aims

Transcatheter aortic valve implantation (TAVI) is an increasingly common procedure in elderly and multimorbid patients with aortic stenosis. We aimed at developing a pre-procedural risk evaluation scheme beyond current surgical risk scores.

Methods

We developed a risk algorithm for 1-year mortality in two cohorts consisting of 845 patients undergoing routine TAVI procedures by commercially available devices, mean age 80.9 ± 6.5, 51 % women. Clinical variables were determined at baseline. Multivariable Cox regression related clinical data to mortality (n = 207 deaths).

Results

To account for variability related to age and sex and by enrolment site we forced age, sex, and cohort into the score model. Body mass index, estimated glomerular filtration rate, hemoglobin, pulmonary hypertension, mean transvalvular gradient and left ventricular ejection fraction at baseline were most strongly associated with mortality and entered the risk prediction algorithm [C-statistic 0.66, 95 % confidence interval (CI) 0.61–0.70, calibration χ ²-statistic = 6.51; P = 0.69]. Net reclassification improvement compared to existing surgical risk predication schemes was positive. The score showed reasonable model fit and calibration in external validation in 333 patients, N = 55 deaths (C-statistic 0.60, 95 % CI 0.52–0.68; calibration χ ²-statistic = 16.2; P = 0.06). Additional measurement of B-type natriuretic peptide and troponin I did not improve the C-statistic. Frailty increased the C-statistic to 0.71, 95 % CI 0.65–0.76.

Conclusions

We present a new risk evaluation tool derived and validated in routine TAVI cohorts that predicts 1-year mortality. Biomarkers only marginally improved risk prediction. Frailty increased the discriminatory ability of the score and needs to be considered. Risk algorithms specific for TAVI may help to guide decision-making when patients are evaluated for TAVI.     

Another step in transcatheter aortic valve implantation: A challenging transcatheter aortic valve implantation procedure in patient with severe peripheral arterial disease

Approximately 25% of patients undergoing transcatheter aortic valve implantation presents significant peripheral arterial disease. The purpose of this case report was to present a feasible approach for transcatheter heart valve in a patient with peripheral arterial disease where the presence of a subclavian stent jutting in the aortic arch made the delivery system passage a challenging procedure.     

Renal dysfunction and transcatheter aortic valve implantation outcomes

Introduction: Transcatheter aortic valve implantation (TAVI) underwent progressive improvements until it became the default therapy for inoperable patients, and a recommended therapy in high-risk operable patients with symptomatic severe aortic stenosis. Recent evidence will further support TAVI as treatment for a growing number of patients.

Areas covered: This review will discuss on the current knowledge about the role of both pre-procedural chronic kidney disease (CKD) and post-procedural acute kidney injury (AKI) in adult patients with severe aortic stenosis undergoing TAVI.

Expert commentary: Pre-procedural CKD is one of the most frequent comorbidities of TAVI patients and has been found to significantly worsen patients’ prognosis at short and long-term follow-up. Similarly, post-procedural AKI is a frequent and relevant complication associated with increased mortality. The risk stratification of the patient, the prevention of complications and the appropriate post-procedural management are the main focus of the future research aimed at further improving clinical outcomes of TAVI patients.     

多层螺旋CT在经导管主动脉瓣植入术中的应用

近年来,经导管主动脉瓣植入术（TAVI）为临床治疗外科手术禁忌的重度高危主动脉瓣狭窄提供了新的选择。治疗前全方位评估患者心脏和大血管的解剖有助于选择合适的TAVI手术方式、降低手术风险。MSCT具有高时间分辨率、高空间分辨率及单次即可完成大范围覆盖扫描等优点,可为TAVI提供更全面的信息。本文对MSCT在TAVI术前评估及术后随访中的应用予以综述。     

Inter-individual variance and cardiac cycle dependency of aortic root dimensions and shape as assessed by ECG-gated multi-slice computed tomography in patients with severe aortic stenosis prior to transcatheter aortic valve implantation: is it crucial for correct sizing?

To evaluate the inter-individual variance and the variability of the aortic root dimensions during the cardiac cycle by computed tomography (CT) in patients with severe aortic stenosis prior to transcatheter aortic valve implantation (TAVI). Fifty-six patients (m/w = 16/40, 81 ± 6.8 years), scheduled for a transapical aortic valve implantation with available preprocedural ECG-gated CT were retrospectively included. The evaluation included sizing of the aortic annulus and the aortic sinus, measurements of the coronary topography, aortic valve planimetry and scoring of calcification. The new defined aortic annulus sphericity ratio revealed a mostly elliptical shape with increasing diastolic deformation. The calculated effective diameter (ED), determined from the annulus’ lumen area, turned out to be the parameter least affected from cardiac cycle changes while systolic and diastolic annulus dimensions and shape (diameter and area) differed significantly (p < 0.001). In about 70 % of the patients with relevant paravalvular leaks the finally implanted prosthesis was too small according to the CT based calculated ED. The ostial height of the coronaries showed a high variability with a critical minimum range <5 mm. The degree of the aortic calcification did not have an influence on the aortic annulus deformation during the cardiac cycle, but on the occurrence of paravalvular leaks. The aortic root anatomy demonstrated a high inter-individual variability and cardiac cycle dependency. These results must be strongly considered during the patient evaluation prior to TAVI to avoid complications. The systolic effective diameter, as measured by ECG-gated CT, represents an appropriate parameter for sizing the aortic annulus.     

Modular aortic valve prosthesis for transcatheter aortic valve implantation: a novel concept with a new implantation method

Transcatheter aortic valve implantation (TAVI) is a relatively new medical intervention. Research on dedicated TAVI devices is an exciting and dynamic field to be explored by professionals involved in technological innovation. The authors describe in this article the first engineering concept and part of the US Patent of a new valve prosthesis. Divided into two pieces to be separately implanted using a single catheter by means of an innovative technique, this device aims at reducing prosthesis and delivery catheter profile. Miniaturization of the valve and delivery system is probably the best solution to reduce the morbidity and mortality that derive from vascular complications associated with TAVI.     

Optimization and simplification of transcatheter aortic valve implantation therapy

Introduction: Transcatheter aortic valve implantation (TAVI) is now a widely adopted therapy for the treatment of elderly patients with severe aortic stenosis. Improved pre-procedural screening, increased operators’ experience and technology advancement have made this technique highly reliable and standardized.

Areas covered: The purpose of this review article is to provide an overview of the strategies that can be adopted to optimize the TAVI procedure (pre-interventional work-up and procedural simplification and early discharge).

Expert commentary: Optimization of TAVI therapy is already a reality and has shown to be safe in most patients, but its penetration has to face with real-world practice. The adoption of a minimalistic and optimized approach requires integration of multidisciplinary competences and an extended, dynamic conception of heart team, which also includes patients’ families, referring cardiologist and general practitioners.     

Antithrombotic pharmacotherapy after transcatheter aortic valve implantation: an update

Introduction: Transcatheter aortic valve implantation (TAVI) is the treatment of choice for a large proportion of patients with severe aortic stenosis. Despite numerous technological and clinical advances, TAVI remains associated with thrombotic complications requiring antithrombotic pharmacotherapy, which exposes to the risk of bleeding, especially in elderly individuals. The optimal antithrombotic regimen following TAVI is uncertain and several investigations are ongoing.

Areas covered: Clinical guidelines are mostly driven by observational trials and experts’ opinions, thus resulting into low-grade level of evidence. The aim of the current review is to critically explore the epidemiology, pathophysiology and prognostic value of thrombotic and bleeding events after TAVI, and to review the current literature on antithrombotic strategies following the procedure.

Expert opinion: Thrombotic and bleeding events remain major complications occurring in the frail population that is currently offered TAVI. Waiting for upcoming evidence from ongoing randomized clinical trials, tailoring antithrombotic therapies based on patients’ characteristics, values and circumstances is a preferable approach.