Clinical outcomes of VNS therapy with AspireSR (including cardiac-based seizure detection) at a large complex epilepsy and surgery centre.

PURPOSE

To compare the efficacy of AspireSR to preceding VNS battery models for battery replacements, and to determine the efficacy of the AspireSR for new implants.

METHODS

Data were collected retrospectively from patients with epilepsy who had VNS AspireSR implanted over a three-year period between June 2014 and June 2017 by a single surgeon. Cases were divided into two cohorts, those in whom the VNS was a new insertion, and those in whom the VNS battery was changed from a previous model to AspireSR. Within each group, the seizure burden was compared between the periods before and after insertion of AspireSR.

RESULTS

Fifty-one patients with a newly inserted AspireSR VNS model had a significant reduction in seizure frequency (p < 0.001), with 59% (n = 30) reporting ≥50% reduction. Of the 62 patients who had an existing VNS, 53% (n = 33) reported ≥50% reduction in seizure burden when the original VNS was inserted. After the battery was changed to the AspireSR, 71% (n = 44) reported a further reduction of ≥50% in their seizure burden. The size of this reduction was at least as large as that resulting from the insertion of their existing VNS in 98% (61/62) of patients.

CONCLUSION

The results suggest that approximately 70% of patients with existing VNS insertions could have significant additional benefit from cardiac based seizure detection and closed loop stimulation from the AspireSR device. For new insertions, the AspireSR device has efficacy in 59% of patients. The 'rule of thirds' used in counseling patients may need to be modified accordingly.