Cerebral Embolic Protection and Stroke-Related Mortality Following Transcatheter Aortic Valve Replacement

Cerebral embolic protection during transcatheter heart interventions

Stroke remains a devastating complication of transcatheter aortic valve replacement (TAVR), with the incidence of clinically apparent stroke seemingly fixed at around 3% despite TAVR's significant evolution during the past decade. Embolic showers of debris (calcium, atheroma, valve material, foreign material) are captured in the majority of patients who have TAVR using a filter-based cerebral embolic protection device (CEPD). Additionally, in systematic brain imaging studies, the majority of patients receiving TAVR exhibit new cerebral lesions. Mechanistic studies have shown reductions in the volume of new cerebral lesions using CEPDs, yet the first randomised trial powered for periprocedural stroke within 72 hours of a transfemoral TAVR failed to meet its primary endpoint of showing superiority of the SENTINEL CEPD. The present review summarises the clinicopathological rationale for the development of CEPDs, the evidence behind these devices to date and the emerging recognition of cerebral embolisation in many non-TAVR transcatheter procedures. Given the uniqueness of each of the various CEPDs under development, specific trials tailored to their designs will need to be undertaken to broaden the CEPD field, in addition to evaluating the role of CEPD in non-TAVR transcatheter heart interventions. Importantly, the cost-effectiveness of these devices will require assessment to broaden the adoption of CEPDs globally.

Cerebral Embolic Protection in Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) is a treatment option for patients with symptomatic severe aortic stenosis across the entire spectrum of surgical risk. Recent trial data have led to the expansion of TAVR into lower-risk patients. With iterative technological advances and successive increases in procedural experience, the occurrence of complications following TAVR has declined. One of the most feared complications remains stroke, and patients consider stroke a worse outcome than death. There has therefore been great interest in strategies to mitigate the risk of stroke in patients undergoing TAVR. In this paper, we will discuss mechanisms and predictors of stroke after TAVR and describe the currently available cerebral embolic protection devices, including their design and relevant clinical studies pertaining to their use. We will also review the current overall evidence base for cerebral embolic protection during TAVR and ongoing randomized controlled trials. Finally, we will discuss our pragmatic recommendations for the use of cerebral embolic protection devices in patients undergoing TAVR.

Outcomes of Cerebral Embolic Protection for Bicuspid Aortic Valve Stenosis Undergoing Transcatheter Aortic Valve Replacement

Background There was limited high-quality evidence that illuminated the efficiency of cerebral embolic protection (CEP) use during transcatheter aortic valve replacement (TAVR) for bicuspid aortic valve (BAV) stenosis. Methods and Results In this retrospective cohort study, patients with BAV stenosis undergoing TAVR with or without CEP were identified by querying the National Inpatient Sample database. The primary end point was any stroke during the hospitalization. The composite safety end point included any in-hospital death and stroke. We applied propensity score-matched analysis to minimize standardized mean differences of baseline variables and compare in-hospital outcomes. From July 2017 to December 2020, 4610 weighted hospitalizations with BAV stenosis undergoing TAVR were identified, of which 795 were treated with CEP. There was a significant increase in the CEP use rate for BAV stenosis (P-trend <0.001). A total of 795 discharges with CEP use were propensity score matched to 1590 comparable discharges but without CEP. CEP use was associated with a lower incidence of in-hospital stroke (1.3% versus 3.8%; P<0.001), which in multivariable regression was also independently associated with the primary outcome (adjusted odds ratio=0.38 [95% CI, 0.18-0.71]; P=0.005) and the safety end point (adjusted odds ratio=0.41 [95% CI, 0.22-0.68] P=0.001). Meanwhile, no significant difference was found in the cost of hospitalization ($46 629 versus $45 147; P=0.18) or the risk of vascular complications (1.9% versus 2.5%; P=0.41). Conclusions This observational study supported CEP use for BAV stenosis, which was independently associated with less in-hospital stroke without burdening the patients with a high hospitalization cost.

Cerebral Embolic Protection Devices: Current State of the Art

Transcatheter aortic valve replacement (TAVR) has become a first-line treatment for severe aortic stenosis with intermediate to high-risk population with its use increasingly expanding into younger and low-risk cohorts as well. Cerebrovascular events are one of the most serious consequential complications of TAVR, which increase morbidity and mortality. The most probable origin of such neurological events is embolic in nature and the majority occur in the acute phase after TAVR when embolic events are most frequent. Cerebral embolic protection devices have been designed to capture or deflect these emboli, reducing the risk of peri-procedural ischaemic events. They also carry the potential to diminish the burden of new silent ischemic lesions during TAVR. Our review explores different types of these device systems, their rationale, and the established clinical data.

Cerebral embolic protection and severity of stroke following transcatheter aortic valve replacement

BACKGROUND

The cerebral embolic protection (CEP) device captures embolic debris during transcatheter aortic valve replacement (TAVR). However, the impact of CEP on stroke severity following TAVR remains unclear. Therefore, we aimed to examine whether CEP was associated with reduced severity of stroke following TAVR.

METHODS

This was a retrospective cohort study of 2839 consecutive patients (mean age: 79.2 ± 9.5 years, females: 41.5%) who underwent transfemoral TAVR at our institution between 2013 and 2020. We categorized patients into Sentinel CEP users and nonusers. Neuroimaging data were reviewed and the final diagnosis of a cerebrovascular event was adjudicated by a neurologist blinded to the CEP use or nonuse. We compared the incidence and severity (assessed by the National Institutes of Health Stroke Scale [NIHSS]) of stroke through 72 h post-TAVR or discharge between the two groups using stabilized inverse probability of treatment weighting (IPTW) of propensity scores.

RESULTS

Of the eligible patients, 1802 (63.5%) received CEP during TAVR and 1037 (36.5%) did not. After adjustment for patient characteristics by stabilized IPTW, the rate of overall stroke was numerically lower in CEP users than in CEP nonusers, but the difference did not reach statistical significance (0.49% vs. 1.18%, p = 0.064). However, CEP users had significantly lower rates of moderate-or-severe stroke (NIHSS ≥ 6: 0.11% vs. 0.69%, p = 0.013) and severe stroke (NIHSS ≥ 15: 0% vs. 0.29%, p = 0.046). Stroke following CEP use (n = 8), compared with stroke following CEP nonuse (n = 15), tended to carry a lower NIHSS (median [IQR], 4.0 [2.0-7.0] vs. 7.0 [4.5-19.0], p = 0.087). Four (26.7%) out of 15 patients with stroke following CEP nonuse died within 30 days, with no death after stroke following CEP use.

CONCLUSIONS

CEP use may be associated with attenuated severity of stroke despite no significant difference in overall stroke incidence compared with CEP nonuse. This finding is considered hypothesis-generating and needs to be confirmed in large prospective studies.

Stroke prevention during and after transcatheter aortic valve implantation: From cerebral protection devices to antithrombotic management

Since its conception, transcatheter aortic valve implantation (TAVI) has undergone important improvements both in the implantation technique and in transcatheter devices, allowing an enthusiastic adoption of this therapeutic approach in a wide population of patients previously without a surgical option and managed conservatively. Nowadays, patients with severe symptomatic aortic stenosis are typically managed with TAVI, regardless of their risk to surgery, improving the prognosis of patients and thus achieving an exponential global expansion of its use. However, thromboembolic and hemorrhagic complications remain a latent concern in TAVI recipients. Both complications can appear simultaneously in the periprocedural period or during the follow-up, and when minor, they resolved without apparent sequelae, but in a relevant percentage of cases, they are devastating, overshadowing the benefit achieved with TAVI. Our review outlines the etiology and incidence of thromboembolic complications associated with TAVI, the main current strategies for their prevention, and the implications of its pharmacological management at the follow-up in a TAVI population, mostly frail and predisposed to bleeding complications.

Cerebral Embolic Protection during Transcatheter Aortic-Valve Replacement

BACKGROUND

Transcatheter aortic-valve replacement (TAVR) for the treatment of aortic stenosis can lead to embolization of debris. Capture of debris by devices that provide cerebral embolic protection (CEP) may reduce the risk of stroke.

METHODS

We randomly assigned patients with aortic stenosis in a 1:1 ratio to undergo transfemoral TAVR with CEP (CEP group) or without CEP (control group). The primary end point was stroke within 72 hours after TAVR or before discharge (whichever came first) in the intention-to-treat population. Disabling stroke, death, transient ischemic attack, delirium, major or minor vascular complications at the CEP access site, and acute kidney injury were also assessed. A neurology professional examined all the patients at baseline and after TAVR.

RESULTS

A total of 3000 patients across North America, Europe, and Australia underwent randomization; 1501 were assigned to the CEP group and 1499 to the control group. A CEP device was successfully deployed in 1406 of the 1489 patients (94.4%) in whom an attempt was made. The incidence of stroke within 72 hours after TAVR or before discharge did not differ significantly between the CEP group and the control group (2.3% vs. 2.9%; difference, -0.6 percentage points; 95% confidence interval, -1.7 to 0.5; P = 0.30). Disabling stroke occurred in 0.5% of the patients in the CEP group and in 1.3% of those in the control group. There were no substantial differences between the CEP group and the control group in the percentage of patients who died (0.5% vs. 0.3%); had a stroke, a transient ischemic attack, or delirium (3.1% vs. 3.7%); or had acute kidney injury (0.5% vs. 0.5%). One patient (0.1%) had a vascular complication at the CEP access site.

CONCLUSIONS

Among patients with aortic stenosis undergoing transfemoral TAVR, the use of CEP did not have a significant effect on the incidence of periprocedural stroke, but on the basis of the 95% confidence interval around this outcome, the results may not rule out a benefit of CEP during TAVR. (Funded by Boston Scientific; PROTECTED TAVR ClinicalTrials.gov number, NCT04149535.).