Self-expanding prostheses for transcatheter aortic valve replacement

Self-expandable transcatheter heart valves for aortic stenosis. Short-term outcome and matched hemodynamic performance

INTRODUCTION AND OBJECTIVES

Aortic self-expandable (SE) transcatheter aortic valve implantation (TAVI) devices are particularly useful for patients with aortic stenosis and small/tortuous vessels, small aortic annuli, or low coronary ostia. However, it is unclear whether the growing range of SE devices shows comparable hemodynamic and clinical outcomes. We aimed to determine the differential hemodynamic (residual valve area and regurgitation) and clinical outcomes of these devices in comparable scenarios.

METHODS

All patients were enrolled from 4 institutions and were managed with 4 different SE TAVI devices. Baseline and follow-up clinical data were collected and echocardiographic tests blindly and centrally analyzed. Patients were compared according to valve type and a 1:1 matched comparison was performed according to degree of calcification, aortic annulus dimensions, left ventricular ejection fraction, and body surface area.

RESULTS

In total, 514 patients were included (Evolut R/PRO, 217; ACURATE neo, 107; ALLEGRA, 102; Portico, 88). Surgical risk scores were comparable in the unmatched population. No differences were observed in the post-TAVI regurgitation rate and in in-hospital mortality (2.7%). The rate of pacemaker implantation at discharge was significantly different among devices (P=.049), with Portico showing the highest rate (23%) and ACURATE neo the lowest (9.5%); Evolut R/PRO and ALLEGRA had rates of 15.9% and 21.2%, respectively. The adjusted comparison showed worse residual TAVI gradients and aortic valve area with ACURATE neo vs ALLEGRA (P=.001) but the latter had higher risk of valve embolization and a tendency for more cerebrovascular events.

CONCLUSIONS

A matched comparison of 4 SE TAVI devices showed no differences regarding residual aortic regurgitation and in-hospital mortality.

Repositionable self-expanding aortic bioprosthesis

INTRODUCTION

Transcatheter aortic valve implantation/replacement (TAVI or TAVR) has been established as a first line therapy in patients with symptomatic severe aortic stenosis (AS) at high or prohibitive surgical risk and as an alternative in elderly patients with intermediate surgical risk. Since its first-in-human procedure in 2002, the past 15-years have shown rapid developments in TAVI technology with the introduction and further improvement of new transcatheter heart valves (THV). Areas covered: There are currently several THV systems available, based on balloon-expandable, self-expandable or other technologies. Some of these are repositionable and retrievable even after partial or full deployment, potentially reducing the risk of malpositioning. The aim of this review is to describe such repositionable self-expandable THV systems. Expert commentary: Repositionability potentially represents a crucial step towards higher safety and efficacy of TAVI. It is unclear if full self-expandability or a combination of self and mechanical expansion will be more advantageous.

Available transcatheter aortic valve replacement technology

Transcatheter aortic valve replacement (TAVR) is an alternative and now recommended therapy for patients who meet indications for surgical valve replacement and are high or prohibitive surgical risk. Available TAVR technologies are rapidly emerging to treat this complex patient population. This review discusses the specific valve designs of the transcatheter heart valves currently used, newer generation modifications to overcome limitations of earlier valve designs, and novel imaging modalities, such as computed tomographic angiography-fluoroscopy and echocardiography-fluoroscopy fusion imaging, available for pre-procedural planning and intra-procedural guidance.

Balloon- or Self-Expandable TAVI: Clinical Equipoise?

Transcatheter aortic valve implantation (TAVI) has become an effective treatment option for patients with severe aortic stenosis and high surgical risk or contraindications for surgical aortic valve replacement. Most of the currently available prostheses employ either balloon-expandable or self-expandable designs. Presently, there is a paucity of data directly comparing these two widely used prosthesis types. Forthcoming trials will reveal whether newer designs of both technologies translate into fewer complications and better outcomes, with expansion of TAVI indications. This manuscript reviews features and clinical outcomes of balloon- and self-expanding prostheses, summarising current data from registries and trials.

Cardiac rehabilitation and mid-term follow-up after transcatheter aortic valve implantation

BACKGROUND

Evaluation of patient outcomes following transcatheter aortic valve implantation (TAVI) has usually been based on survival and clinical improvement. Studies on quality of life are limited, and data from comprehensive assessments after the procedure are lacking.

METHODS

Sixty patients referred for cardiac rehabilitation after TAVI underwent in-hospital and after-discharge multidimensional assessments to evaluate clinical, functional, and nutritional statuses, degree of autonomy, cognitive impairment, depression and quality of life.

RESULTS

On admission to rehabilitation, approximately half of the patients had severe functional impairment and dependence for basic activities of daily living. During their hospital stay, one-third of the patients suffered significant clinical complications and two had to be transferred to the implantation center. Despite this, the overall outcome was very good. All of the remaining patients were clinically stable at discharge and functional status, autonomy and quality of life were improved in most. During a mean follow-up of 540 days (range: 192-738 days), five patients died from noncardiac causes, three were hospitalized for cardiac events, and nine for non cardiac reasons. Functional status and autonomy remained satisfactory in the majority of patients and most continued to live independently.

CONCLUSIONS

Patients referred for rehabilitation after TAVI are often very frail, with a high grade of functional impairment, dependence on others and high risk of clinical complications. During a rehabilitation programme, based on a multidimensional assessment and intervention, most patients showed significant improvement in functional status, quality of life, and autonomy, which remained stable in the majority of subjects during mid-term follow-up.

Transcatheter aortic valve implantation in the elderly: who to refer?

In recent years, experience with transcatheter aortic valve implantation has led to improved outcomes in elderly patients with severe aortic stenosis (AS) who may not have previously been considered for intervention. These patients are often frail with significant comorbid conditions. As the prevalence of AS increases, there is a need for improved assessment parameters to determine the patients most likely to benefit from this novel procedure. This review discusses the diagnostic criteria for severe AS and the trials available to aid in the decision to refer for aortic valve procedures in the elderly.