As proof of the validity and reliability of the company’s algorithms for the detection of large vessel occlusions (LVO), a multi-center open perspective study was performed. Skin displacement over the carotid artery was recorded using bimorph piezoelectric sensors (AverttoTM 101) during endovascular procedures. During these procedures, a balloon is inflated inside the artery creating a temporary occlusion. These recordings were then used to analyze the pulse waves in the signals and determine whether a difference could be seen during the procedures compared to the baseline before the procedure. Previously, pulse wave analysis was successfully shown to distinguish between the signals ipsilateral and contralateral to the occlusion in stroke patients [1], and pulse wave velocity was used to determine a correlation in acute stroke patients between cerebral arterial stiffness and intracranial artery calcification [2].
The procedures in this study include carotid artery stenting, aneurysms, and thrombectomies. Thrombectomies, although the minority of cases (n=3), are particularly informative as they are performed on patients who developed LVOs and therefore allow a comparison of the recorded pulse waves during a naturally occurring LVO versus during the period following the procedure after the occlusion has been cleared.
Methods
At the time of analysis, three subjects were recorded while undergoing a thrombectomy. Here we present the results from a representative subject who underwent a thrombectomy. The subject (GMC027) is a 77-year-old male with an LVO in his right middle cerebral artery.
Pulse wave velocity (PWV) was calculated using the distance between sensors (15 cm) divided by the difference in time between the pulse wave foot recording in two adjacent sensors (channels 0 and 1) placed on the carotid artery ipsilateral to the occlusion. Analysis along with calculation of statistics was performed in Matlab (R2023a).
Results
Figure 1 shows the average PWV with the x-axis going forward in time from left to right with measurements before the procedure, during the procedure, both during and between the inflation of balloons, and post-procedure. The successful treatment of the stroke by the performance of a thrombectomy is accompanied by a clear decrease in the PWV, as can be seen by comparing the values before and after the procedure (2.33 ± 0.18 m/s and 1.76 ± 0.65 m/s respectively, t score = 10.6 p<0.0001).
This result is proof of concept that hemodynamic changes, as recorded by sensors over the carotid artery, can be used to detect differences caused by the presence of a stroke-inducing LVO.
