Impaired Cerebrovascular Autoregulation in Large Vessel Occlusive Stroke after Successful Mechanical Thrombectomy: A Prospective Cohort Study

Abstract

Introduction: Successful thrombectomy improves morbidity and mortality after stroke. The present prospective, observational cohort study investigated a potential correlation between the successful restoration of tissue perfusion by mechanical thrombectomy and intact cerebrovascular autoregulation (CA).

Objective: Status of CA in patients with large vessel occlusive stroke after thrombectomy.

Methods: After thrombectomy CA was measured using transcranial Doppler ultrasound. For this purpose a moving correlation index (Mxa) based on spontaneous arterial blood pressure fluctuations and corresponding cerebral blood flow velocity changes was calculated. CA impairment was defined by Mxa values more than .3.

Results: Twenty patients with an acute occlusion of the middle cerebral artery or distal internal carotid artery were included. A successful recanalization of the occluded vessel via interventional thrombectomy was achieved in 10 of these patients (successful recanalization group), while in 10 patients mechanical recanalization failed or could not be applied (no recanalization group). Mean Mxa at stroke side was .58 ± .21 Table 2a in patients with successful intervention. At the unaffected hemisphere Mxa was .50 ± .20 Table 2a in successful recanalization group and .45 ± .24 Table 2b in no recanalization group without statistically significant differences. Based on the previously defined Mxa cut off more than .3, CA impairment was observable in all successful recanalized patients and in 8 of 10 patients with unsuccessful interventional treatment.

Conclusions: These results suggest that brain perfusion may be affected due to impaired CA even after successful mechanical thrombectomy. Therefore, a tight blood pressure management is of great importance in post-thrombectomy stroke treatment to avoid cerebral hypo- and hyperperfusion.

Keywords: Acute ischemic stroke; cerebrovascular autoregulation; large vessel occlusion; mechanical thrombectomy; neurocritical care.