Safety and efficacy of starting warfarin after two consecutive platelet count rises in heparin-induced thrombocytopenia.

INTRODUCTION: Current guidelines on the treatment of heparin-induced thrombocytopenia (HIT) recommend warfarin initiation when platelet levels recover to 150×10(9)/L or more. However, many patients may not achieve this platelet level or may have slow platelet recovery. The aim of this study is to determine if initiating warfarin when platelets start trending upward instead of at a specific level is safe and effective in patients diagnosed with HIT. MATERIALS AND METHODS: Two groups of patients diagnosed and treated for HIT in a tertiary care hospital were assessed for HIT-related outcomes: 28 patients had warfarin initiated after platelets recovered to 150×10(9)/L or more and 30 patients had warfarin initiated prior to platelet recovery. RESULTS: There was no significant difference between the rate of thrombosis, venous limb gangrene, or limb amputation. Three patients died during the data collection period, all deemed to be unrelated to HIT by independent investigators. The average hospital length of stay was 22.2±12.7days and 38.8±19.1days for patients who started warfarin at platelets less than 150×10(9)/L and platelets greater than or equal to 150×10(9)/L respectively (P=0.0002). CONCLUSIONS: The data suggests that the absolute platelet level at which warfarin is initiated does not affect the rate of thrombosis or mortality but may shorten overall hospital length of stay and associated costs. Therefore, it may be more important to observe an upward trend in platelets rather than striving to achieve an absolute platelet level before starting warfarin in patients with HIT.

Bivalirudin in pediatric patients maintained on extracorporeal life support.

OBJECTIVE: Anticoagulation with heparin is standard of care for patients maintained on extracorporeal life support. Very limited evidence exists for the use of alternative anticoagulants during extracorporeal life support. Patients with heparin-induced thrombocytopenia, heparin resistance, and evidence of significant thrombosis while on heparin may be candidates for alternative anticoagulation. The objective of this analysis is to present evidence for the use of bivalirudin during extracorporeal life support in pediatric patients. DESIGN: Case series. SETTING: University of California, Davis Medical Center. PATIENTS: Twelve critically ill, pediatric patients receiving bivalirudin for anticoagulation during extracorporeal life support. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Twelve patients meeting entry criteria received bivalirudin during the study period. The median patient age was 8 days (range, 1 d to 6 yr). Eight patients were neonates. Eight patients were male. Nine patients were supported with venoarterial extracorporeal life support. Median duration of extracorporeal life support was 226 hours (range, 111-913) and median time on bivalirudin was 92 hours (range, 60-230). Bivalirudin bolus doses were administered to select patients without bleeding complications. The maintenance dose that corresponded with initial target activated partial thromboplastin time ranged from 0.045 to 0.48 mg/kg/hr with a median rate of 0.16 mg/kg/hr. The median dose for days 1, 3, and 5 was 0.135, 0.175, and 0.267 mg/kg/hr, respectively. The correlation (r2) between dose adjustment and activated partial thromboplastin time response was 0.264. CONCLUSIONS: This is the largest case series describing the use of a direct thrombin inhibitor in pediatric extracorporeal life support patients. The maintenance dose range reflected considerable inter-patient variability. There was an observed increase in dose requirements with time. Bivalirudin, with close monitoring, is a potential option for pediatric patients on extracorporeal life support who have developed heparin-induced thrombocytopenia, heparin resistance, or significant thrombosis while on heparin.

Reversing dabigatran in life-threatening bleeding occurring during cardiac ablation with factor eight inhibitor bypassing activity.

OBJECTIVES: We report a case of a patient receiving dabigatran who developed a life-threatening bleeding complication during cardiac ablation that rapidly resolved after administration of Factor Eight Inhibitor Bypassing Activity (FEIBA). BACKGROUND: Therapeutic anticoagulation with warfarin during cardiac ablation has been shown to reduce the risk of stroke and systemic embolism. Cardiac tamponade is a potentially life-threatening procedural complication requiring emergent reversal of anticoagulation and pericardiocentesis. Dabigatran is superior to warfarin in preventing stroke and systemic embolism in nonvalvular atrial fibrillation, but has not been evaluated for use during cardiac ablation. Dabigatran is without a known reversal agent and, should tamponade occur during ablation, it is unclear what reversal strategy could be used to establish hemostasis. METHODS AND RESULTS: A 67-year-old man with history of atrial fibrillation with rapid ventricular rate, two previous atrial fibrillation ablations, and prescribed dabigatran 150 mg bid was admitted for an atrial fibrillation ablation procedure. The last dabigatran dose was 7 hours prior to procedure. During the procedure, a transseptal perforation occurred, requiring an emergent pericardiocentesis. Within 60 minutes, approximately 4.5 L of blood was removed via the pericardiocentesis. Low-dose FEIBA (3159 units, 26 U/kg actual body weight) over 15 minutes was administered. Hemostasis was noted within minutes of initiating the infusion with cessation of bleeding after administration was complete. CONCLUSION: This case report describes the potential ability of a low dose of the activated prothrombin complex concentrate, FEIBA, to reestablish hemostasis independent of the pharmacologic effects of dabigatran. Additional studies are warranted to confirm the findings of our observation.