Characteristics of Silent Cerebral Embolism During TAVR

Most patients undergoing transcatheter aortic valve replacement (TAVR) are prone to develop silent cerebral ischemic lesions (SCIL), which are more common in patients with greater baseline cerebral white matter damage and those who use non-balloon-expandable bioprostheses, according to study results published in JACC: Cardiovascular Interventions. Furthermore, these lesions may impair neurocognitive function.

Previous studies reported that SCIL occur in most patients undergoing TAVR. The goal of the current study was to explore the natural history and clinical relevance of SCIL using serial magnetic resonance imaging (MRI) and neurocognitive assessments.

Prior to TAVR, a neurocognitive evaluation and a cerebral MRI to evaluate baseline status and age related white matter changes (ARWMC) were performed. The imaging study was repeated post-operatively to assess the occurrence, location, number, and dimensions of SCIL. A third MRI was completed at the 3- to 5-month follow-ups of patients that developed SCIL. The neurocognitive evaluation was performed again at discharge and at the 3-month follow-up.

The final study sample included 96 patients (mean age, 83±5 years) who had both baseline and post-procedural MRI. Of these, 5.2% had a prior history of stroke or transient ischemic attack, while 25.0% had a history of atrial fibrillation. Although the trans-subclavian access was used in a small minority of patients (16.7%), most cases (83.3%) used the transfemoral access.

A total of 238 new post-procedural SCIL were observed in 73 participants (76%) after a median of 7 days. Among patients with SCIL, the median number of lesions was 2, with a median diameter of 4.5 mm per lesion.

At multivariate analysis, the only independent predictors of post-procedural SCIL occurrence included a higher degree of baseline ARWMC (hazard ratio [HR], 2.2; 95% CI, 1.1- 4.4; P =.023) and the use of non-balloon-expandable bioprostheses (HR, 5.2; 95% CI, 1.5 to 18.7; P =.011).

A total of 47 patients underwent a third MRI following TAVR.Out of the 146 post-procedural SCIL, only 39 (26.7%) evolved into a gliotic lesion at the same site, with 33 patients (70.2%) no longer displaying any evidence of lesions at the sites of all post-procedural SCIL.

Neurocognitive assessments were completed in 83 patients, including 64 with and 19 without post-procedural SCIL. SCIL occurrence was associated with a more pronounced transient neurocognitive decline early after TAVR and with a lower recovery at the 3-month follow-up. 3-months after TAVR, only patients with SCIL still showed a persisting significant decline in neurocognitive function compared to baseline (P =.02).

The researchers acknowledged several study limitations, including the relatively slow enrollment of patients and subsequent potential time-related bias, the slight delay in post-procedural MRI compared to previous studies, and the refusal of many participants to undergo the third MRI and/or neurocognitive assessment. 

“Studies are needed to identify strategies to prevent cerebral embolization and cognitive deterioration, particularly when extending TAVR to younger patients,” concluded the researchers.

Disclosure: This clinical trial was supported by Edwards Lifesciences and Medtronic. Please see the original reference for a full list of authors’ disclosures.

Reference

De Carlo M, Liga R, Migaleddu G, et al. Evolution, predictors, and neurocognitive effects of silent cerebral embolism during transcatheter aortic valve replacement [published online ahead of print, 2020 May 8]. JACC Cardiovasc Interv. doi:10.1016/j.jcin.2020.03.004