Acute ischemic stroke resulting from tandem lesions - insights from a Thrombectomy Capable Stroke Center in Kashubia region (Poland). The frequency, causes, procedural intricacies, and complications of tandem lesions compared to isolated intracranial artery occlusions and isolated extracranial internal carotid artery occlusion.

INTRODUCTION: Tandem lesions, where extracranial and intracranial vascular pathology coexists, have a poor prognosis and are a significant cause of acute ischemic stroke (AIS) with large vessel occlusion (LVO); they present unique challenges in diagnosis and endovascular treatment.

AIM OF THE STUDY: This retrospective study analyzed demographic parameters, risk factors, qualification procedures, fibrinolytic therapy, interventional management, complications, technical aspects, and clinical outcomes in tandem-occlusion anterior circulation stroke (TOS) patients treated at a Thrombectomy Capable Stroke Center (TCSC) in Wejherowo from 2020 to 2024. Acute stroke patients with TOS were compared to two groups: patients with isolated intracranial artery occlusion (iLVO) and patients with isolated extracranial internal carotid artery (iICA) lesion.

MATERIAL AND METHODS: A total number of 193 patients who underwent endovascular therapy (EVT) were involved. The comparison between selected populations was performed to analyze frequency, risk factors, procedure complexity, complications, and clinical outcome.

RESULTS: In the observed group the prevalence of tandem lesions was 17.1%, isolated extracranial internal carotid artery (ICA) occlusion was 11.4%, and isolated intracranial artery occlusion-71.5%. Tandem and ICA occlusion patients were younger (66.21 ± ± 9.8 vs. 70.34 ± 12.16; p < 0.01) and had a higher prevalence of smoking (45% vs. 26.1%; p < 0.05) compared to the intracranial LVO group. The latter had a higher rate of atrial fibrillation (21.2% vs. 60.9%; p < 0.001). Time intervals, including onset-to- -reperfusion (301.66 vs. 246.15 minutes; p < 0.01) and related to it: groin-to-first pass, groin-to-recanalization were significantly prolonged in the tandem group. Clinical outcomes, as measured by the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS), were worse in the tandem group compared to both the intracranial LVO (mRS 0-2: 24.2% vs. 44.9%; p < 0,01; NIHSS: 9.96 vs. 7.01; p < 0.01) and isolated extracranial ICA occlusion groups (mRS 0-2: 24.2% vs. 59.1%; p < 001; NIHSS: 9.96 vs. 4.53; p < 0.01). There were no significant differences in complication rates between the groups.

CONCLUSIONS AND CLINICAL IMPLICATIONS: In the analyzed cohort of interventionally treated AIS patients, the presence of tandem lesions was correlated with poor clinical outcomes and associated with the presence of atherosclerosis risk factors. Endovascular procedures in these cases were more complex and involved extended time intervals. Conversely, patients with isolated intracranial lesions were generally older, with atrial fibrillation being the primary risk factor. In these patients, endovascular procedure times were shorter and resulted in more favorable clinical outcomes.