Timing of vitamin K antagonist re-initiation following intracranial hemorrhage in mechanical heart valves: Systematic review and meta-analysis.
BACKGROUND
While evidence supports resumption of vitamin K antagonists (VKAs) among mechanical heart valve (MHV) patients presenting with anticoagulant-associated intracranial hemorrhage (ICH), ideal timing of resumption is uncertain.


OBJECTIVE
To determine the optimal timing of VKA re-initiation and its associated clinical outcomes.


METHODS
We performed a systematic review and a meta-analysis of studies published from January 1950 to August 2015. We extracted data on the location of initial ICH, use of cranial surgery, presence of atrial fibrillation, MHV type and position, number of MHVs, and timing of VKA resumption. Outcomes including valve thrombosis, thromboembolic events or ICH recurrence were recorded. Meta-regression analysis was conducting with controlling for covariates. We calculated absolute risks, and assessed the effect of anticoagulant resumption timing on ICH recurrence.


RESULTS
23 case-series and case-reports were identified. Overall ICH recurrence was 13% (95% confidence interval [CI], 7%-25%), while valve thrombosis and ischemic strokes occurred at 7% (95% CI, 3%-17%) and 12% (95% CI, 5%-23%) respectively. A trend towards lower ICH recurrence was observed with delayed VKA resumption (slope estimate -0.2154, p=0.10). Recurrence rate ranged from 50% with VKA resumption at 3days to 0% with resumption at 16days.


CONCLUSION
Among patients with MHV, there is inadequate data to suggest an optimal timing of VKA re-initiation following an ICH, though delayed restart appears to be protective against recurrence but is associated with higher risk of thrombosis. Our analysis suggests 4-7days might be an ideal time with least risk of thrombosis or ICH recurrence.
['AlKherayf|Fahad|F|', 'Xu|Yan|Y|', 'Gandara|Esteban|E|', 'Westwick|Harrison|H|', 'Moldovan|Ioana Doina|ID|', 'Wells|Philip S|PS|']
D000925:Anticoagulants D006350:Heart Valve Prosthesis D006801:Humans D020300:Intracranial Hemorrhages D013927:Thrombosis D014812:Vitamin K D014859:Warfarin
Intracranial hemorrhage Anticoagulant Mechanical valve Warfarin