Balloon- or Self-Expandable TAVI: Clinical Equipoise?

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.

Smart materials in cardiovascular implants: Shape memory alloys and shape memory polymers

Smart materials have intrinsic properties that change in a controlled fashion in response to external stimuli. Currently, the only smart materials with a significant clinical impact in cardiovascular implant design are shape memory alloys, particularly Nitinol. Recent prodigious progress in material science has resulted in the development of sophisticated shape memory polymers. In this article, we have reviewed the literature and outline the characteristics, advantages, and disadvantages of shape memory alloys and shape memory polymers which are relevant to clinical cardiovascular applications, and describe the potential of these smart materials for applications in coronary stents and transcatheter valves.