Introduction: Newborns constitute a large proportion of childhood arterial ischemic stroke (AIS). Relevance of prothrombotic risk factors in neonatal arterial ischemic stroke (NAIS) is unknown.

Objectives: To study the impact of prothrombotic risk factors on NAIS.

Methods: A single-centre retrospective analysis (July/1999-August/2009) of NAIS cases was conducted. Prothrombotic testing included protein-C(PC), protein-S(PS), antithrombin, anticardiolipin-antibodies(ACLA), lupus-anticoagulant, lipoprotein-(a), homocysteine, factor-VIII, factor-IX, factor-XI and Factor-V Leiden, prothrombin G20210A (PTG) and MTHFR gene mutations. Data on non-inherited coexisting risk factors [congenital heart disease (CHD), vasculopathy, head/neck disorders, systemic disease] and anti-thrombotic therapy (ATT) [Aspirin/anticoagulants] were collected. Stroke recurrence was defined as new ischemic lesion(s) on follow-up neuroimaging. Neurologic outcome was assessed by the validated Pediatric Stroke Outcome Measure (any neurodeficit considered abnormal). Measures of association (Fisher’s Exact) between risk factors, ATT and outcomes were studied.

Results: Seventy-six out of 88 NAIS cases (52 males) had prothrombotic testing. Of these 9(12%) had at least one prothrombotic risk factor [PC, ACLA, heterozygous PTG (2 each) and ACLA+factor-VIII, lipoprotein-a, MTHFR+elevated homocysteine (1 each)], and 62(85%) had at least 1 non-prothrombotic risk factor [majority: CHD(81%)]. ATT was administered in 37/88(43%). Stroke recurred in 8/88(13%). Presence of prothrombotic risk factor predicted stroke recurrence [OR:6.2(95%CI:1.18-32.56); p=0.0485)] and trend towards poor outcome (median f/u: 2-yrs]) [(OR: 6.97(95%CI: 0.82-59.34); p=0.069]. Neither presence of non-inherited risk factors nor ATT predicted outcome.

Conclusion: Prothrombotic abnormalities were encountered in a relatively small proportion of newborns with AIS, but they were associated with unfavorable outcome. A larger prospective multicentre study is merited to corroborate these findings.