Efficacy and safety of cerebral embolic protection systems during transcatheter aortic valve replacement: a review of current clinical findings

ABSTRACT

Introduction

Cerebrovascular events are one of the most serious consequences after transcatheter aortic valve replacement (TAVR). More than half of the cerebrovascular events following TAVR are due to procedure-related emboli. Embolic protection devices (EPDs) have the potential to decrease cerebrovascular events during TAVR procedure. However, randomized controlled trials (RCTs) have not conclusively determined if EPDs are effective, likely because of small number of patients enrolled. However, meta-analyses and propensity-matched analyses from large registries have shown efficacy and suggest the importance of EPDs in prevention of stroke during TAVR and perhaps other structural heart procedures.

Areas covered

This review will focus on clinical and histopathologic studies examining the efficacy, safety, and histopathologic device capture findings in the presence and absence of EPDs during TAVR procedures.

Expert opinion

Clinical studies have not conclusively determined the efficacy of EPDs. Current ongoing large-scale RCT (PROTECTED TAVR [NCT04149535]) has the potential to prove their efficacy. Histopathological evaluation of debris captured by EPDs contributes to our understanding of the mechanisms of TAVR procedure-related embolic events and suggests the importance of preventing cerebral embolization of debris released during this and other structural heart procedures.

KEYWORDS:

• Transcatheter aortic valve replacement
• aortic stenosis
• stroke
• transient ischemic attack
• cerebrovascular event
• embolic protection device
• sentinel

Article highlights

• Cerebrovascular events are among the most serious transcatheter aortic valve replacement (TAVR) complications. These cerebrovascular events are thought to be embolic in nature because (1) most events occur within several days after the procedure, (2) the lesions are often multiple, diffuse, distributed in all cerebrovascular territories, and (3) transcranial Doppler studies have shown that high-intensity signals (HITS) which are a surrogate marker for microembolization are seen in almost all the phases of the procedure. Therefore, the use of an embolic protection device (EPD) is a reasonable strategy for the prevention of periprocedural cerebrovascular events during TAVR.

• Recently, many types of EPDs have been developed and the feasibility of which is increasingly being confirmed in clinical trials. Their features vary in terms of the mechanism of protection, access vessel, device size, pore size, and protection of other organs. Six randomized controlled trials (RCTs) have been completed so far, but no study has met its primary clinical endpoint due to the small sample size and the overall low occurrence of cerebrovascular events post TAVR.

• Many propensity-matched analyses from large registries and meta-analyses have been performed to determine the efficacy of EPDs, however, these studies have shown conflicting results.

• Histopathological studies have shown that captured debris in EPDs are present in 74 to 100% of patients. The histopathological evaluation of EPD has the potential to highlight the underlying risk factor responsible for embolization during the TAVR procedure.

• Recently ongoing RCT, the PROTECTED TAVR trial has the potential to demonstrate the clinical efficacy in the prevention of stroke after TAVR.

Declaration of interest

CVPath Institute has received institutional research support from NIH-HL141425; Leducq Foundation Grant; 480 Biomedical; 4C Medical; 4Tech; Abbott; Accumedical; Amgen; Biosensors; Boston Scientific; Canon U.S.A.; Cardiac Implants; Celonova; Claret Medical; Concept Medical; Cook; CSI; DuNing, Inc; Edwards LifeSciences; Emboline; Endotronix; Envision Scientific; Lutonix/Bard; Gateway; Lifetech; Limflo; MedAlliance; Medtronic; Mercator; Merill; Microport Medical; Microvention; Mitraalign; Mitra assist; NAMSA; Nanova; Neovasc; NIPRO; Novogate; Occulotech; OrbusNeich Medical; Phenox; Profusa; Protembis; Qool; ReCor Medical; Senseonics; Shockwave; Sinomed; Spectranetics; Surmodics; Symic; Vesper; W.L. Gore; Xeltis. AV Finn has received honoraria from Abbott Vascular; Biosensors; Boston Scientific; Celonova; Cook Medical; CSI; Lutonix Bard; Sinomed; Terumo Corporation; and is a consultant to Amgen; Abbott Vascular; Boston Scientific; Celonova; Cook Medical; Lutonix Bard; Sinomed. R Virmani has received honoraria from Abbott Vascular; Biosensors; Boston Scientific; Celonova; Cook Medical; Cordis; CSI; Lutonix Bard; Medtronic; OrbusNeich Medical; CeloNova; SINO Medical Technology; ReCor Medical; Terumo Corporation; W. L. Gore; Spectranetics; and is a consultant Abbott Vascular; Boston Scientific; Celonova; Cook Medical; Cordis; CSI; Edwards Lifescience; Lutonix Bard; Medtronic; OrbusNeich Medical; ReCor Medical; Sinomededical Technology; Spectranetics; Surmodics; Terumo Corporation; W. L. Gore; Xeltis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosure

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.