Cerebral protection during TAVI still offers weak evidence, but there is hope

Silent ischemic embolic lesions are common after transcatheter aortic valve implantation (TAVI). The use of cerebral protection devices might reduce the occurrence of these embolic lesions. Multiple studies with different devices, designs, and outcomes challenge the usefulness of cerebral protection during TAVI.

A comprehensive analysis of the literature was necessary to obtain a more robust idea about these devices. In consequence, the aim of this meta-analysis is to determine whether the use of cerebral protection devices during TAVI reduces both silent ischemic and clinically evident cerebrovascular events.

Sixteen studies involving 1170 patients (865 subjects with cerebral protection; 305 control subjects) were included. The success rate for protection device delivery before valve implantation was reported in all studies and was achieved in about 94.5% of patients.

The meta-analysis could not confirm or exclude the usefulness of cerebral protection devices in terms of clinically evident stroke (relative risk [RR]: 0.70; 95% confidence interval [CI]: 0.38-1.29; p = 0.26) or 30-day mortality (RR: 0.58; 95% CI: 0.20-1.64; p = 0.30).

There were no significant differences in the magnetic resonance imaging scans as regards new-single, multiple, or total number of lesions.

The usefulness of protection devices was evident in volume, since these were associated with a significantly smaller ischemic volume per lesion (p = 0.002) and smaller total volume of lesions (p = 0.05).

According to the subgroup analysis by type of valve used, patients who received self-expanding devices seemed to benefit more.

Conclusion

The use of cerebral protection devices during TAVI might be associated with smaller volume of silent ischemic lesions, in particular, and smaller total volume of lesions, but no significant differences were observed as regards the number of lesions observed and the clinical usefulness of the device.

Editorial

The usefulness of cerebral protection devices is far from being a settled issue. There are several devices available featuring very different designs, which makes it difficult to assume the existence of a “class effect.” Typical hard endpoints such as death or stroke do not seem to change, but only a few studies have assessed rigurously other endpoints such as cognitive impairment. Now that TAVI is gradually involving a younger, lower-risk population, who will live many more years after valve replacement, cognitive function is a variable that must be taken into account.

The meta-analysis lacked individual data for each particular patient, which means that a more robust adjustment as regards baseline differences such as atrial fibrillation, prior stroke, or peripheral vascular disease, was impossible.

Original title: Cerebral Embolic Protection Devices During Transcatheter Aortic Valve Implantation. Systematic Review and Meta-Analysis.

Reference: Rodrigo Bagur et al. Stroke. 2017 May;48(5):1306-1315.

We are interested in your opinion. Please, leave your comments, thoughts, questions, etc., below. They will be most welcome.