Thrombophilic Variants and Clinical Outcomes in Young Ischaemic Stroke Patients Undergoing Mechanical Thrombectomy: A Retrospective Cohort Study

Objective: This study aimed to characterise thrombophilic variants in young patients (≤50 years) undergoing mechanical thrombectomy (MT) for acute ischaemic stroke and to determine their clinical relevance. In addition, outcomes in young patients were compared with those in older patients to provide clinical context for age-related differences in presentation and recovery. Methods: This retrospective cohort study included consecutive patients with large-vessel occlusion stroke who achieved successful recanalisation (TICI ≥ 2b) after MT at a comprehensive stroke centre. Patients were stratified into young (≤50 years) and non-young (>50 years) groups. Clinical variables, thrombophilia markers, and functional outcomes were analysed. Results: Among 679 included patients, 76 (11.2%) were classified as young (mean age 39.2 ± 7.4 vs. 72.0 ± 11.4 years in older patients). Young patients had lower baseline NIHSS scores (14.6 ± 7.9 vs. 17.7 ± 4.7; mean difference −3.1 points) and markedly lower 1-month NIHSS scores (2.4 ± 2.3 vs. 9.5 ± 5.6; mean difference −7.1 points; both p < 0.001). Three-month mortality was 11.8% in young patients and 17.6% in older patients; however, this difference was not statistically significant (p = 0.2565). The MTHFR C677T variant was associated with lower post-procedural NIHSS scores (p = 0.021), while the distribution of hereditary thrombophilia markers did not differ significantly across vascular territories. Elevated homocysteine levels were associated with poorer 3-month outcomes (p = 0.0156). Conclusions: Young stroke patients undergoing MT demonstrated markedly better neurological and functional outcomes than older patients; however, three-month mortality did not differ significantly between the groups. Although several inherited thrombophilic variants were identified in the young cohort, most showed no consistent association with clinical outcomes.