THE SAFETY OF ANTIPLATELET REVERSAL PROCEDURES BEFORE EMERGENCY NEUROSURGERY IN PATIENTS WITH RUPTURED ANEURYSMS POST-EMBOLIZATION: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS AND PRIMARY STUDIES

Abstract

Introduction: Stent-assisted coil embolisation and flow diversion have expanded the endovascular armamentarium for acutely ruptured wide-necked and complex intracranial aneurysms, but these devices oblige dual antiplatelet therapy in patients who have just sustained subarachnoid haemorrhage and frequently require emergency intracranial surgery for hydrocephalus, intraparenchymal clot, or refractory intracranial hypertension. The safety of attempting to reverse platelet inhibition before such emergency neurosurgery remains contested. Methods: The study strictly adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. Eligible studies were randomized controlled trials and comparative primary studies reporting antiplatelet exposure or reversal in adults undergoing emergency intracranial procedures, with emphasis on aneurysmal subarachnoid haemorrhage after stent-assisted coiling or flow diversion. Thirteen outcomes were prespecified. Dichotomous data were pooled with DerSimonian-Laird random-effects models; heterogeneity was quantified by Cochran Q, τ², and I²; and certainty of evidence was rated using GRADE. Results: Sixty-three records corresponding to fifty-nine primary studies were included, comprising four randomized controlled trials and fifty-five non-randomized comparative or cohort studies. In the pooled analysis of nine comparative cohorts (1,401 patients and procedures), antiplatelet exposure at the time of cerebrospinal-fluid diversion conferred a fourfold increase in radiographically evident catheter-tract haemorrhage (odds ratio 4.00; 95% confidence interval 2.59 to 6.18; P<0.0001; I²=5.7%). The hazard persisted for symptomatic haemorrhage across three cohorts (odds ratio 3.96; 95% CI 1.54-10.16; P=0.004; I²=0%). Restoration of platelet function with allogeneic platelet concentrate did not translate into clinical benefit and was associated with net harm in the randomized trial (adjusted common odds ratio for death or dependence 2.05; 95% CI 1.18-3.56). By contrast, pharmacological rescue with desmopressin was associated with significant reduction in haematoma expansion (odds ratio 0.32; 95% CI 0.12-0.86; P=0.024; I²=29.7%). Pre-procedural P2Y12 reaction units discriminated peri-procedural complications with moderate accuracy (area under the curve 0.74; optimal window 118-144 units), whereas thromboelastography with platelet mapping performed no better than chance (area under the curve 0.53). Catheter placement after versus before antiplatelet loading was associated with significant excess of tract haemorrhage (odds ratio 2.46; 95% CI 1.16-5.20; P=0.019; I²=0%). Certainty of evidence was moderate for the primary haemorrhagic outcome and low to very low for all mortality and functional outcomes. Conclusion: Antiplatelet exposure after endovascular treatment of a ruptured aneurysm significantly and substantially increases catheter-related intracranial haemorrhage during emergency neurosurgery, but pharmacological reversal by platelet transfusion does not mitigate this hazard and may worsen outcome. Safety in this population is achieved principally by procedural planning, by agent selection favouring reversible short-acting inhibitors, and by selective use of desmopressin rather than by reflexive platelet transfusion. Adequately powered randomized trials of desmopressin, of tirofiban or cangrelor bridging, and of assay-guided reversal in the specific post-embolisation subarachnoid haemorrhage population are urgently required.