Successful treatment with rFVIIa of spontaneous intracerebral hemorrhage in a patient with mechanical prosthetic heart valves

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.

Rapid reversal of warfarin-associated hemorrhage in the emergency department by prothrombin complex concentrates

Life-threatening warfarin-associated hemorrhage is common, with a high mortality. In the United States, the most commonly used therapies--fresh frozen plasma and vitamin K--are slow and unpredictable and can result in volume overload. Outside of the United States, prothrombin complex concentrates are often used instead; these pooled plasma products reverse warfarin anticoagulation in minutes rather than hours. This article reviews the literature relating to warfarin reversal with fresh frozen plasma, prothrombin complex concentrates, and recombinant factor VIIa and provides elements for a management protocol based on this literature.

Thromboembolic risks of recombinant factor VIIa Use in warfarin-associated intracranial hemorrhage: a case-control study

BACKGROUND

Recombinant factor VIIa (rFVIIa) may be used for rapid hemostasis in life-threatening hemorrhage. In warfarin-associated intracerebral hemorrhage (wICH), FVIIa use is controversial and may carry significant thromboembolic risks. We compared incidence of baseline thromboembolic risk factors and thromboembolism rates in wICH patients treated with additional rFVIIa to those treated with standard therapy of fresh frozen plasma (FFP) and vitamin K alone.

METHODS

We identified 45 consecutive wICH patients treated with additional rFVIIa over 5-year period, and 34 consecutive wICH patients treated with standard therapy alone as comparison group. We compared the incidence of post-hemorrhage cardiac and extra-cardiac thromboembolic complications between two treatment groups, and used logistic regression to adjust for significant confounders such as baseline thromboembolic risk factors. We performed secondary analysis comparing the quantity of FFP transfused between two treatment cohorts.

RESULTS

Both rFVIIa-treated and standard therapy-treated wICH patients had a high prevalence of pre-existing thromboembolic diseases including atrial fibrillation (73% vs 68%), deep venous thrombosis (DVT) or pulmonary embolism (PE) (22% vs 18%), coronary artery disease (CAD) (38% vs 32%), and abnormal electrocardiogram (EKG) (78% vs 85%). Troponin elevation following wICH was prevalent in both groups (47% vs 41%). Clinically significant myocardial infarction (MI), defined as troponin > 1.0 ng/dL, occurred in 13% of rFVIIa-treated and 6% of standard therapy-treated patients (p=0.52). Past history of CAD (p=0.0061) and baseline abnormal EKG (p=0.02) were independently associated with clinically significant MI following wICH while rFVIIa use was not. The incidences of DVT/PE (2% vs 9%; p=0.18) and ischemic stroke (2% vs 0%; p=0.38) were similar between two treatment groups. Recombinant FVIIa-treated patients had lower mean INR at 3 (p=0.0001) and 6 hours (p<0.0001) and received fewer units of FFP transfusion (3 vs 5; p=0.003).

CONCLUSIONS

Pre-existing thromboembolic risk factors as well as post-hemorrhage troponin elevation are prevalent in wICH patients. Clinically significant MI occurs in up to 13% of wICH patients. rFVIIa use was not associated with increased incidence of clinically significant MI or other venous or arterial thromboembolic events in this wICH cohort.

Management dilemmas in patients with mechanical heart valves and warfarin-induced major bleeding

Management of warfarin-induced major bleeding in patients with mechanical heart valves is challenging. There is vast controversy and confusion in the type of treatment required to reverse anticoagulation and stop bleeding as well as the ideal time to restart warfarin therapy safely without recurrence of bleeding and/or thromboembolism. Presently, the treatments available to reverse warfarin-induced bleeding are vitamin K, fresh frozen plasma, prothrombin complex concentrates and recombinant activated factor VIIa. Currently, vitamin K and fresh frozen plasma are the recommended treatments in patients with mechanical heart valves and warfarin-induced major bleeding. The safe use of prothrombin complex concentrates and recombinant activated factor VIIa in patients with mechanical heart valves is controversial and needs well-designed clinical studies. With regard to restarting anticoagulation in patients with warfarin-induced major bleeding and mechanical heart valves, the safe period varies from 7-14 d after the onset of bleeding for patients with intracranial bleed and 48-72 h for patients with extra-cranial bleed. In this review article, we present relevant literature about these controversies and suggest recommendations for management of patients with warfarin-induced bleeding and a mechanical heart valve. Furthermore, there is an urgent need for separate specific guidelines from major associations/ professional societies with regard to mechanical heart valves and warfarin-induced bleeding.

Urgent reversal of vitamin K antagonist therapy

In the developed world, an increasing number of patients receive therapy with vitamin K antagonists (VKA). This group of patients poses an additional challenge in the perioperative management of emergency surgery and trauma. The present review offers a detailed description of some treatment options for reversal of VKA therapy. Optimal treatment of the anticoagulated patient requires a well-balanced intervention securing a reduced risk of haemorrhagic surgical complications as well as optimal anticoagulation post-operatively without exposing the patient to an increased risk of thromboembolic complications. The following factors must be considered in VKA-treated patients scheduled for emergency surgery: (1) the indication for VKA therapy, including the risk of thromboembolic events when the International normalized ratio (INR) is reduced, (2) type of surgery, including the risk of haemorrhagic complications and (3) the pharmacodynamic/-kinetic profile of the therapy used to revert the VKA therapy. Therapeutic options for acute reversal of VKA therapy include: vitamin K, fresh frozen plasma (FFP), prothrombin complex concentrate (PCC) and perhaps activated recombinant factor VII. PCC is a relatively new drug in some European countries and clinical experience is limited compared with the use of FFP. Reversal of VKA anticoagulation with PCC is faster and more efficient compared with FFP, but there are currently no randomized studies demonstrating an improved clinical outcome.

Exploratory study on the reversal of warfarin with rFVIIa in healthy subjects

The use of warfarin has a well-known bleeding risk. Recombinant activated factor VII (rFVIIa) is a non–plasma-derived, rapid-acting, and rapidly infused potential treatment. This randomized, single-center, placebo-controlled, double-blinded, dose-escalation, exploratory phase 1 trial assessed safety and effects of rFVIIa in reversing warfarin-induced changes in bleeding and coagulation parameters, using a punch biopsy–induced bleeding model in healthy subjects. The effects of warfarin (experiment 1) and rFVIIa (5-80 μg/kg; experiment 2) were evaluated. Outcomes were bleeding duration, blood loss, coagulation parameters, and safety. Warfarin treatment significantly increased bleeding duration and blood loss from pretreatment (experiment 1, 12 subjects). However, these parameters after rFVIIa treatment were not significantly different from placebo (experiment 2, 85 subjects). Mean activated partial thromboplastin time, prothrombin time, and international normalized ratio were reduced from warfarin-elevated levels. rFVIIa (80 μg/kg) significantly reversed warfarin effects on all thromboelastography parameters, compared with placebo (P < .05), and returned the thrombin generation speed to baseline. There were no thromboembolic or serious adverse events. In this exploratory trial, the reversal of warfarin effects was observed in the thromboelastography, thrombin generation, and clotting assays. However, this reversal did not translate to improvements in the bleeding model parameters evaluated in the punch biopsy model. Trial registration is exempt (phase 1).

Iatrogenic causes of an ICH: OAT therapy

Current understanding of oral anticoagulant treatment and related intracerebral haemorrhage remains rather limited as compared to that of spontaneous intracerebral haemorrhage. Although intracerebral haemorrhage is the most serious complication of oral anticoagulant treatment, standardized treatment guidelines are still lacking. The currently employed treatments are aimed at normalization of the iatrogenic coagulation impairment, and are not based on randomized controlled trials evidence. Since most patients with oral anticoagulant treatment-intracerebral haemorrhage are at high risk of cardio-embolism and often myocardial infarction, it is uncertain whether the use of procoagulant treatments for oral anticoagulant treatment-intracerebral haemorrhage may increase their risk of thrombotic complications. Patients who receive chronic oral anticoagulant treatment urgently require effective treatments for acute oral anticoagulant treatment-intracerebral haemorrhage, and therefore controlled clinical trials are needed.

The headache over warfarin in British neurosurgical intensive care units: a national survey of current practice

OBJECTIVE

To ascertain current British practice regarding the emergency medical management of patients who sustain a spontaneous intracerebral haemorrhage (ICH) whilst receiving warfarin therapy and to compare this with established national and international guidelines.

DESIGN

Standardised, telephone based, questionnaire survey.

SETTING

All 32 adult British neuroscience intensive care units (ICUs)

PARTICIPANTS

Duty consultant of each neuroscience ICU.

RESULTS

Response rate was 100%. The international normalised ratio (INR) would be reversed by over 90% of ICU consultants treating patients on warfarin with an ICH, except patients with mechanical heart valves (MHV), when only 59.4% would reverse. Prothrombin complex concentrate (PCC) was used by 15 ICUs (46.9%); however, only six units (18.8%) apply reversal strategies with PCC and intravenous vitamin K in accordance with national guidelines. Fresh frozen plasma (FFP) continues to be used by 71.9% of the ICUs. A protocol for warfarin reversal in ICH was present in five ICUs, of which four followed national guidelines. None of the units that use FFP had a protocol. Following ICH, two-thirds of the ICUs (65.6%) would commence bridging heparinisation in the first 4 days for MHV patients and 25% would recommence warfarin before, and 64.5% after, 7 days.

CONCLUSION

There is considerable variation in practice amongst clinicians who regularly manage these patients and, in most cases (81.2%), practice is not in keeping with national or international guidelines. This study has demonstrated the need amongst senior ICU clinicians for a heightened awareness of current treatment recommendations and the availability of effective haemostatic therapies.

rFVIIa--for acute rebleeding of a cerebral cavernous malformation

Recurrent bleeding episodes of cavernomas especially in the brainstem can cause progressive neurological deficits. Therefore brainstem cavernomas are still a therapeutic dilemma and a treatment challenge for the neuro critical care community. We report a 39-year-old woman with spontaneous ataxia diplopia and vomiting, who has been treated for multiple intracerebral cavernomas during the last 10 years. A cerebral computed tomography (cCT) revealed a re-bleeding cavernoma in the left cerebral peduncle with consecutive obstructive hydrocephalus. As a result of the difficult anatomical location, no surgical approach was possible. As an off-label treatment, recombinant activated factor VII (rFVIIa) was administered to prevent possible further bleeding and especially further sequelae. The patient recovered well and no adverse events and especially no further bleeding of the cavernoma were observed. To our knowledge, this is the first report of the safe and successful use of rFVIIa to treat re-bleeding episodes in cavernomas. Further clinical studies are needed to specify the future potential of rFVIIa.