Single mean arterial blood pressure drops during stroke thrombectomy under general anaesthesia are associated with poor outcome

Abstract

Background: We examined the influence of periprocedural blood pressure (BP), especially critical BP drops, on 3-month functional outcome in stroke patients undergoing mechanical thrombectomy (MT) under general anaesthesia (GA).

Methods: We screened all patients with anterior circulation large vessel occlusion receiving MT under GA at our centre from January 2011 to June 2016 and selected those who had continuous invasive periinterventional BP monitoring. Clinical and radiological data were prospectively collected as part of an ongoing cohort study, monitoring data were extracted from electronic anaesthesia records. We used uni- and multivariable regression to investigate the association of BP values with unfavourable outcome, defined as modified Rankin Scale scores 3-6 3 months post-stroke.

Results: 115 patients were included in this study (mean age 65.3 ± 13.0 years, 55.7% male). Periinterventional systolic, diastolic, and mean arterial BP (MAP) values averaged across MT had no effect on outcome. However, single BP drops were related to unfavourable outcome, with absolute MAP drops showing the highest association compared to both systolic and relative BP drops (with reference to pre-interventional values). The BP value with the strongest association with unfavourable outcome was identified as an MAP ever < 60 mmHg (p = 0.01) with a pronounced effect in patients with poor collaterals. An MAP < 60 mmHg remained independently associated with poor functional outcome in multivariable analysis (p < 0.01).

Conclusions: For patients undergoing MT under GA, single MAP drops < 60 mmHg are independently related to unfavourable 3-month outcome. Therefore, every effort should be made to prevent periinterventional hypotensive episodes, especially below this threshold.

Keywords: Anaesthesia; Blood pressure; Large vessel occlusion; Neurocritical care; Stroke; Thrombectomy.

Fig. 1

Study flowchart

Fig. 2

Continuous electronic periinterventional blood pressure monitoring in a representative patient, showing a severe blood pressure drop after induction of anaesthesia (red cross)

Fig. 3

Modified Rankin Scale scores at 3 months of patients without and with periinterventional MAP drops below 60 mmHg, showing worse functional outcome of patients with such drops (p < 0.01)