Purpose of the review
Warfarin and the newer oral anticoagulants are efficacious in preventing stroke and pulmonary embolism in patients with atrial fibrillation and deep vein thrombosis. It remains a difficult therapeutic decision to use anti-thrombotic agents in elderly, where there is increased incidence of atrial fibrillation. Bleeding complications, especially life-threatening intracranial hemorrhage, are inevitable in this population because of increased incidence of falls. In this review, we analyze the incidence and prevalence of intracranial hemorrhage with warfarin and the newer oral anticoagulants
After nearly fifty years of warfarin use, newer oral anticoagulants are surpassing its use in the management of both arterial and venous thrombotic states. Though there has been this transition to newer anticoagulants, there is no ideal anticoagulant. Issues regarding predictors of hemorrhage, how to monitor anticoagulant therapy, early diagnosis and improving survival of patients with intracranial hemorrhage, still remain.
Although the use of newer anticoagulants is gaining momentum, because of the decreased incidence of intracranial hemorrhage, their use is still being debated in patients with underlying cancer, lupus anticoagulant state, metal valve prosthesis and pregnancy. We keenly await the results of multi-center trials to resolve this issue.
Keywords: Warfarin; Newer oral anticoagulants; Atrial fibrillation, DVT, Intracranial hemorrhage
According to data from the National Electronic Injury Surveillance System (NEISS), warfarin is the most common drug-related cause of hospitalization (accounting for 33% of such hospitalizations) for adverse events among older adults in the United States . Incidence of atrial fibrillation increases with age, with a prevalence of 0.1% in people over 55 years of age and 90% in those over than 80 years old. The number of patients with atrial fibrillation is likely to increase 2.5-fold during the next 50 years, reflecting the growing proportion of elderly individuals .
Incidence of intra-cerebral hemorrhage in patients receiving oral anticoagulants ranges from 0.3% to 1% per year . About 50-90% of intracranial hemorrhage (ICH) cases associated with warfarin use, occur while the INR is within the therapeutic range . ICH has a 7- to 10-fold increased incidence with warfarin use, over patients not on oral anticoagulant therapy to an absolute rate of nearly 1%/yr for many stroke-prone patients. The risk of warfarin-induced hemorrhage is particularly high when the INR exceeds four, as well as during the initial months of therapy . However, Diamond et al found that the incidence of over-anticoagulation was only seen in 23% of patients developing subdural hematomas on warfarin therapy and there was no correlation between anticoagulant status and the extent of bleeding or prognosis.
Warfarin-related ICH carries a particularly high risk of neurologic deterioration and death because of a high rate of hematoma expansion of about 50%. The risk of hematoma expansion is unknown with newer oral anticoagulants [7, 8]. However, novel oral anticoagulants (NOACs)–apixaban, dabigatran, and rivaroxaban–have a significantly lower risk of intra-cerebral hemorrhage.
The relative risk (RR) reduction of stroke by oral anticoagulant therapy is about 68% and the beneficial effect of anti-thrombotic therapy, far outweighs the risks of intra-cerebral bleeding in the elderly. Hence, age in itself is not considered acontraindication to treatment, and other risk factors are to be considered (Table 1). Serious bleeding, including warfarin induced ICH, is challenging and management includes rapid reversal of anticoagulation with hemostatic drug therapies, such as vitamin K, fresh frozen plasma (FFP), prothrombin complex concentrates (PCCs), recombinant factor VIIa (rFVIIa) or hemodialysis and idarucizumab with dabigatran. These therapies may not always be sufficient to stabilize the patient’s clinical condition, and in the absence of randomized controlled trials, the preferred approach remains unclear and mortality remains high .
Pharmacology of Oral Anticoagulants:
Warfarin blocks vitamin K dependent, gamma carboxylation of coagulation factors II, VII, IX and X. Dabigatran is a direct inhibitor of thrombin and rivaroxaban selectively inhibits factor Xa. The anticoagulant effect of warfarin is caused by a small fraction of the drug, since most (97 -99%) is protein bound (mainly to albumin), thus rendering it ineffective. Unlike the newer oral anticoagulants , the half-life of warfarin varies greatly among individuals, ranging from 35 to 45 hours (Table 2) . Patients taking warfarin had a doubling in the rate of intra-cerebral hemorrhage mortality in a dose-dependent manner . The hypothesis is that warfarin compromises the normal hemostatic mechanism of tissue factor interacting with activated factor VII to initiate the coagulation cascade. Rivaroxaban is distributed heterogeneously to tissues and organs, and exhibits only moderate tissue affinity and does not substantially penetrate the blood–brain barrier. As thrombin has been implicated in microvessel injury during cerebral ischemia, dabigatran decreases the risk of intra-cerebral hemorrhage by direct inhibition of the thrombin-mediated increase in cerebral endothelial cell permeability. Dabigatran also does not increase the risk of secondary hemorrhage after thrombolysis, as seen in various rodent models of ischemia and re-perfusion . The incidence of intracranial bleeding is apparently less with the newer oral anticoagulants when compared to warfarin .
Drug interaction and oral anticoagulant therapy:
Warfarin is 99% plasma bound . Alterations in cytochrome P450-mediated drug metabolism or disturbances in drug-protein binding lead to altered anticoagulant activity of warfarin. Interaction with drugs, releases unbound free molecule increasing bleeding tendency, which some think may lead to a paradigm shift in the management of anti-thrombotic therapy . Compared to warfarin, dabigatran does not have CYP450 interaction, but it is a substrate of P-glycoprotein (P-gp) and therefore has drug interaction with rifampin, verapamil, carbamazepine, ketoconazole and dronedarone. Rivaroxaban interacts with agents including erythromycin, clarithromycin, ritonavir and ketoconazole [18, 19]. But unlike warfarin, dabigatran and rivaroxaban have no interaction with herbs and food, including food additives.
Duration of anticoagulation and ICH:
With the newer oral anticoagulants, the time interval between the duration of anticoagulation and the occurrence of internal hemorrhage is not available. With warfarin, 11% of the bleeds occurred within the first month, 20% within 2 months and 33% within 6 months. About 42% had been on anticoagulation for more than 3 years and majority of patients with subdural hematomas did not have a definite history of trauma . Some studies found the highest incidence of ICH within the first 6 months (the duration of treatment for provoked first-time DVT/PE), but others found no relationship to the duration of anticoagulant therapy and incidence of ICH [20, 21].
Trials of oral anticoagulant therapy and incidence of ICH:
The cumulative data from a meta-analysis of these trials revealed that the risk of ICH was about 50% less with NOACs (Table 3). When compared to warfarin, the reduction risk ratio was 0.44 (with 95% confidence interval) with both anti-thrombin and factor Xa inhibitor (RE-LY, ARISTOTLE,ROCKET& ENGAGE) trials. NOACs and LMWH had a similar incidence of internal hemorrhage. As expected, there was an increased risk of ICH with NOACs when compared with placebo (RR 3.31 with 95% confidence interval). Interestingly in one study, 150 mg of dabigatran, twice a day, had an incidence of ICH of 0.1 per 100 patient years, while the incidence of dosing dabigatran 110 mg twice a day was 0.3 per 100 patient years . All of the NOACs are qualitatively more effective than warfarin in significantly reducing ICH. But individually the magnitude of reduction in the risk of ICH varied among individual agents. However this does not prove that NOACs are far superior to warfarin, because in these trials comparing NOACs with warfarin, patients who had underlying cancer, lupus anticoagulant syndrome and patients with prosthetic cardiac metal valve were excluded. Also, in patients taking NOACs, there were case reports of increased GI bleeding, but a systematic review has found no evidence of increased GI bleeding with NOACs .
Management & Prevention:
Because of the high mortality involved with intracranial bleed, either from warfarin or the newer oral anticoagulants, it is prudent to attempt to avoid ICHs.
About one third of patients on oral anti-coagulant therapy have been started on the medication because of unproven benefit. Avoiding drug interaction, patient education, drug compliance, caution with co-morbidities, discontinuing anticoagulant if appropriate, avoiding the use of alcohol and caution in patients with thrombocytopenia, is essential  and holding further anti-coagulation when patients develop sudden onset of severe headache is mandatory. Supra-therapeutic levels of oral anticoagulants in circulation can be avoided by prevention of drug- drug interactions, patient education, adequate therapeutic monitoring of INR with warfarin therapy, avoiding antithrombin/anti Xa inhibitors in severe renal failure, management of co-morbidities including severe diastolic hypertension and appropriate management of falls, especially in elderly individuals. Unfortunately in more than two thirds of patients, ICH occurs when the INR is within the therapeutic range [35, 36].
In the management of warfarin-associated ICH, the administration of vitamin K alone is inadequate, as vitamin K does not reverse the hemostatic defect for many hours. Hemostatic levels of factor IX cannot be achieved, in most instances, by the conventional use of FFP in patients requiring reversal of warfarin . In 2013, the FDA-approved prothrombin complex concentrate (PCC) for the urgent reversal of warfarin induced acute major bleeding. Rapid reversal of coagulopathy in geriatric patients on warfarin is pivotal to limit the extent of ICH. Larger volumes of FFP needed to reverse warfarin-induced coagulopathy are also associated with fluid retention and congestive heart failure in elderly patients. PCC on the other hand allows a more rapid reversal, as compared to standard treatment with only FFP and vitamin K .
In one non-randomized study, the time for warfarin reversal was significantly shorter with the use of PCC as compared to FFP (PCC-65 minutes and FFP-256 minutes, P<0.05) . However, patients with a prior history of PE or DVT who receive three factor PCC for warfarin-associated ICH are 4.5 times more likely to sustain a VTE within 30 days . In an observational study of patients with central nervous system bleeding, patients who received recombinant factor VII (rFVIIa), the time to INR normalization was approximately 2 hours . In the absence of prospective, randomized data, recommendations regarding the reversal of warfarin-induced coagulopathy must rely on expert opinion [42-44]. No mortality benefit has been shown for one treatment regimen over another . In the case of newer oral anticoagulants, the initial treatment is to hold further exposure to the agent and activated charcoal to prevent enteric absorption. With dabigatran, hemodialysis and the specific antibody idarucizumab appears to be very effective . Direct and indirect factor Xa inhibitors have no specific FDA approved agent available to counteract their effect. The present management includes: holding further exposure to the agent, use of activated charcoal, administration of prothrombin complex concentrate and rFVIIa. The antidotes under trial for direct and indirect factor Xa include: andexanet alpha and ciraparantag. Andexanet alpha is a modified protein extracted from coagulation factor X, eliciting a significant, dose-dependent reduction in plasma anti-Xa activity . Ciraparantag is a synthetic, small molecule antidote, binding to direct and indirect factor Xa inhibitors, including rivaroxaban, apixaban, edoxaban, enoxaparin and fondaparinux[48, 49]. Its mechanism of action for drug reversal includes binding to the drug and forming strong, non-covalent hydrogen bonds .
Recommencing oral anticoagulants after ICH:
There are no guidelines regarding oral anticoagulants following ICH. Patients have been recommenced on oral anticoagulant therapy for prosthetic heart valve following ICH and no life-threatening bleeding complications have been reported. Following ICH, reinitiating anti-thrombotic therapy must be made based on the relative risks versus benefits in individual patients, which will vary depending on the site of hemorrhage, continuing risk factors for further hemorrhage, and indication for anticoagulation. Warfarin decreased the absolute rate of primary events by 0.7%per year (95% CI-0.4 to 1.7) and untreated atrial fibrillation was associated with risk of thromboembolism of 4.5% per year . As re-bleeding is rare and the individuals have high a incidence of thromboembolic episodes without anticoagulant therapy, reinitiating therapy in patients with prosthetic metal valves is generally advised.
Risk of thrombosis after reversal of oral anticoagulant therapy:
The exact incidence of thromboembolic phenomena after stopping the incriminated anticoagulant and reversal of its effect is unknown , especially with the newer oral anticoagulants. In patients with prosthetic heart valves (PHV) the risk of thrombosis without anticoagulation may be as high as 22% per year . In patients with atrial fibrillation, the risk of arterial thromboembolic episodes approaches 20%, especially when patients have additional risk factors. Interruption of oral anticoagulants for three to five days following a major bleed and for whom follow-up data were available, no further hemorrhages were recorded after a mean time of 2.8 years . The thrombotic episodes following cessation of anti-thrombotic agents is mainly influenced by the underlying cause for initiation of thrombotic therapy including anti-phospholipid antibody syndrome, ball mitral valve versus aortic valve, associated vascular disease, underlying cardiac rhythm. However, overall duration of anticoagulant therapy and compliance with anticoagulant medication plays a role in determining whether thrombotic episodes will occur following cessation of therapy.
The overall mortality rate for ICH secondary to anticoagulant use, ranges between 45-60% . About 70% of intracranial hemorrhage is intra-cerebral hemorrhage. The mortality rate is high in Asians, the elderly, and patients with higher diastolic blood pressure . There appears to be no difference in the fatality rate following intracranial hemorrhage among patients receiving warfarin or other newer oral anticoagulant agents.
In the three major trials (Re-Ly -2009, Rocket -2011 and Engage trials -2013), the incidence of intra-cerebral hemorrhage was less with the newer oral anticoagulants when compared to warfarin. In patients who developed ICH, more than 50% were in the desired therapeutic range. About 70% of patients had intra-cerebral hemorrhages and the rest subdural hematomas. Subarachnoid hemorrhage occurred in a minority of patients. Major bleeding complications in these multi-center trials were, between 2.5-3% but risk of intracranial bleeding was 50 % lower with other newer oral anticoagulant agents than with warfarin .However, these trials excluded patients that were pregnant, over the age of 80, had a diagnosis of cancer or lupus anticoagulant syndrome. Warfarin is still the drug of choice for patients with cancer, circulating anticoagulant, heparin-induced thrombocytopenia and valvular atrial fibrillation. As increasing age, the level of oral anticoagulant, genetic factors, high prevalence of concurrent cerebrovascular conditions, such as cerebral amyloid angiopathy or previous strokes, lower hemoglobin concentrations, renal dysfunction and low platelet count are independent predictors of intracranial hemorrhage; caution needs to be exerted when oral anticoagulant use is contemplated . Obesity is independently associated with anticoagulation reversal failure . Interestingly in J-RHYTHM study, concurrent use of aspirin and warfarin has not been shown to produce higher incidence of ICH (as patients may need dual therapy with atrial fibrillation and systemic arterial disease) . The newer oral anticoagulants will most probablyreplace warfarin for treatment of atrial fibrillation and venous thromboembolism. Currently, outcomes of ICH with the antidotes for the newer oral agents are still unknown. Because of high morbidity and mortality, our aim should be to prevent ICH via the judicious use of oral anticoagulants and by maintaining a constant dialogue between the patient, provider and pharmacy teams.
- Budnitz DS1, Lovegrove MC, Shehab N, Richards CL (2011) Emergency hospitalizations for adverse drug events in older Americans. N Engl J Med 365: 2002-2012.
- Go AS (2001) Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. Jama 285: 2370-2375.
- Hart RG1, Boop BS, Anderson DC (1995) Oral anticoagulants and intracranial hemorrhage. Facts and hypotheses. Stroke 26: 1471-1477.
- Butler AC1, Tait RC (1998) Management of oral anticoagulant-induced intracranial haemorrhage. Blood Rev 12: 35-44.
- Hylek E M, Evans-Molina C, Shea C, Henault LE, Regan S, (2007) Major hemorrhage and tolerability of warfarin in the first year of therapy among elderly patients with atrial fibrillation Circulation 115: 2689-96
- Diamond T1, Gray WJ, Chee CP, Fannin TF (1988) Subduralhaematoma associated with long term oral anticoagulation. Br J Neurosurg 2: 351-355.
- Simonsen CZ, Steiner T, TietzeA&Damgaard D (2014) Dabigatran-related intracerebral hemorrhage resulting in hematoma expansion. J Stroke Cerebrovasc Dis 23: 133-4.
- Effect of long-term oral anticoagulant treatment on mortality and cardiovascular morbidity after myocardial infarction (1994). Anticoagulants in the Secondary Prevention of Events in Coronary Thrombosis (ASPECT) Research Group. Lancet. 343: 499-503.
- Poli D, Antonucci E, Testa S, Tosetto A, Ageno W, et al. (2011) Bleeding risk in very old patients on vitamin K antagonist treatment: results of a prospective collaborative study on elderly patients followed by Italian Centres for Anticoagulation. Circulation 124: 824-829.
- Cervera A1, Amaro S, Chamorro A (2012) Oral anticoagulant-associated intracerebral hemorrhage. J Neurol 259: 212-224.
- Palareti G & C Legnani (1996) Warfarin withdrawal. Pharmacokinetic-pharmacodynamic considerations ClinPharmacokinet 30: 300-13.
- Rosand J1, Eckman MH, Knudsen KA, Singer DE, Greenberg SM (2004) The effect of warfarin and intensity of anticoagulation on outcome of intracerebral hemorrhage. Arch Intern Med 164: 880-884.
- Fleck RA1, Rao LV, Rapaport SI, Varki N (1990) Localization of human tissue factor antigen by immunostaining with monospecific, polyclonal anti-human tissue factor antibody. Thromb Res 59: 421-437.
- Sun L, et al. (2013) Anticoagulation with dabigatran does not increase secondary intracerebralhaemorrhage after thrombolysis in experimental cerebral ischaemia ThrombHaemost 110: 153-61.
- Hart RG1, Diener HC, Yang S, Connolly SJ, Wallentin L, et al. (2012) Intracranial hemorrhage in atrial fibrillation patients during anticoagulation with warfarin or dabigatran: the RE-LY trial. Stroke 43: 1511-1517.
- Smith SA1, Kraft SL, Lewis DC, Freeman LC (2000) Plasma pharmacokinetics of warfarin enantiomers in cats. J Vet PharmacolTher 23: 329-337.
- Saeed W1, Burke JF2, Mirrani G3, Sirinivasa M4, Nabi U2, et al. (2016) AParadigm Shift: The New Novel Oral Anticoagulation Agents. J Coll Physicians Surg Pak 26: 611-619.
- Stöllberger C1, Finsterer J2 (2016) Interactions between non-vitamin K oral anticoagulants and antiepileptic drugs. Epilepsy Res 126: 98-101.
- Stöllberger C1, Finsterer J (2015) Relevance of P-glycoprotein in stroke prevention with dabigatran, rivaroxaban, and apixaban. Herz 40 Suppl 2: 140-145.
- Kase CS, Robinson RK, Stein RW, DeWitt LD, Hier DB, et al. (1985) Anticoagulant-related intracerebral hemorrhage. Neurology 35: 943-948.
- Levine M and J Hirsh (1986) Hemorrhagic complications of long-term anticoagulant therapy for ischemic cerebral vascular disease Stroke. 17: 111-6.
- Lundstrom T and L Ryden (1989) Haemorrhagic and thromboembolic complications in patients with atrial fibrillation on anticoagulant prophylaxis. J Intern Med. 225: 137-42.
- Secondary prevention in non-rheumatic atrial fibrillation after transient ischaemic attack or minor stroke. EAFT (European Atrial Fibrillation Trial) Study Group. Lancet (1993) 342: 1255-62.
- Kanter MC et al. (1994) Carotid stenosis in patients with atrial fibrillation. Prevalence, risk factors, and relationship to stroke in the Stroke Prevention in Atrial Fibrillation Study. Arch Intern Med. 154: 1372-7.
- Bleeding during antithrombotic therapy in patients with atrial fibrillation. The Stroke Prevention in Atrial Fibrillation Investigators (1996). Arch Intern Med. 156: 409-16.
- Patel M.R et al. (2011) Rivaroxaban versus warfarin in nonvalvular atrial fibrillation. N Engl J Med. 365: 883-91.
- Giugliano RP et al. (2013) oxaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 369: 2093-104.
- Connolly SJ et al. (2009) Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. 361: 1139-51.
- Granger CB et al. (2011) Apixaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 365: 981-92.
- Connolly, S.J., et al., Apixaban in patients with atrial fibrillation. N Engl J Med, 2011. 364(9): p. 806-17.
- Caldeira D et al. (2015) Intracranial hemorrhage risk with the new oral anticoagulants: a systematic review and meta-analysis. J Neurol. 262: 516-22.
- Larsen TB et al. (2013) Efficacy and safety of dabigatranetexilate and warfarin in “real-world” patients with atrial fibrillation: a prospective nationwide cohort study. J Am CollCardiol. 61: 2264-73.
- Caldeira D et al.(2015) Systematic review with meta-analysis: the risk of major gastrointestinal bleeding with non-vitamin K antagonist oral anticoagulants. Aliment PharmacolTher. 42: 1239-49.
- Lip GY, DG Beevers and JR Coope (1996) ABC of atrial fibrillation. Atrial fibrillation in general and hospital practice. Bmj. 312: 175-8.
- Lieberman A et al. (1978) Intracranial hemorrhage and infarction in anticoagulated patients with prosthetic heart valves. Stroke. 9: 18-24.
- Lau CP et al. (1991) Cerebral haemorrhage in anticoagulated patients with non-septic mechanical valvular prosthesis. Int J Cardiol. 30: 289-96.
- Makris M et al. (1997) Emergency oral anticoagulant reversal: the relative efficacy of infusions of fresh frozen plasma and clotting factor concentrate on correction of the coagulopathy. ThrombHaemost. 77: 477-80.
- Edavettal M et al. (2014) Prothrombin complex concentrate accelerates international normalized ratio reversal and diminishes the extension of intracranial hemorrhage in geriatric trauma patients. Am Surg. 80: 372-6.
- Yanamadala V et al. (2014) Reversal of warfarin associated coagulopathy with 4-factor prothrombin complex concentrate in traumatic brain injury and intracranial hemorrhage. J ClinNeurosci. 21: 1881-4.
- Felton D et al. (2015) Risk of Venous Thromboembolism After Receiving Prothrombin Complex Concentrate for Warfarin-associated Intracranial Hemorrhage. J Emerg Med.
- Lin J et al. (2003) The use of recombinant activated factor VII to reverse warfarin-induced anticoagulation in patients with hemorrhages in the central nervous system: preliminary findings. J Neurosurg. 98:737-40.
- Aguilar M. et al. (2007) Treatment of warfarin-associated intracerebral hemorrhage: literature review and expert opinion. Mayo ClinProc . 82: 82-92.
- Ananthasubramaniam K et al. (2001) How safely and for how long can warfarin therapy be withheld in prosthetic heart valve patients hospitalized with a major hemorrhage? Chest. 119: 478-84.
- Fong WC et al. (2014) The benefit of prothrombin complex concentrate in decreasing neurological deterioration in patients with warfarin-associated intracerebralhaemorrhage. Hong Kong Med J. 20: 486-94.
- Bechtel BF et al. (2011) Treatments for reversing warfarin anticoagulation in patients with acute intracranial hemorrhage: a structured literature review. Int J Emerg Med. 4: 40.
- Marino KK1, Santiago RA2, Dew RB 3rd2, Berliner N3, Connors JM3, et al. (2016) Management of Dabigatran-Associated Bleeding with Two Doses of Idarucizumab Plus Hemodialysis. Pharmacotherapy 36: e160-160e165.
- Lu G1, DeGuzman FR, Hollenbach SJ, Karbarz MJ, Abe K, et al. (2013) A specific antidote for reversal of anticoagulation by direct and indirect inhibitors of coagulation factor Xa. Nat Med 19: 446-451.
- Ansell JE et al. (2016) Ciraparantag safely and completely reverses the anticoagulant effects of low molecular weight heparin. Thromb Res.
- Rogers KC1, Shelton MP, Finks SW (2016) Reversal Agents for Direct Oral Anticoagulants: Understanding New and Upcoming Options. Cardiol Rev 24: 310-315.
- Smythe MA1, Trujillo T2, Fanikos J3 (2016) Reversal agents for use with direct and indirect anticoagulants. Am J Health Syst Pharm 73: S27-48.
- Babikian VL et al. (1988) Resumption of anticoagulation after intracranial bleeding in patients with prosthetic heart valves. Stroke. 19: 407-8.
- Eckman MH et al. (2003) Can patients be anticoagulated after intracerebral hemorrhage? A decision analysis. Stroke. 34: 1710-6.
- [No authors listed] (1994) Warfarin versus aspirin for prevention of thromboembolism in atrial fibrillation: Stroke Prevention in Atrial Fibrillation II Study. Lancet 343: 687-691.
- Butler A, Tait RC (2004) Restarting oral anticoagulation after intracranial hemorrhage. Stroke 35: e5-6.
- Punthakee X1, Doobay J, Anand SS (2002) Oral-anticoagulant-related intracerebral hemorrhage. Thromb Res 108: 31-36.
- Neau JP1, Couderq C, Ingrand P, Blanchon P, Gil R; VGP Study Group (2001) Intracranial hemorrhage and oral anticoagulant treatment. Cerebrovasc Dis 11: 195-200.
- Tzourio C1, Arima H, Harrap S, Anderson C, Godin O, et al. (2008) APOE genotype, ethnicity, and the risk of cerebral hemorrhage. Neurology 70: 1322-1328.
- Verdecchia P1, Angeli F2, Aita A3, Bartolini C3, Reboldi G4 (2016) Why switch from warfarin to NOACs? Intern Emerg Med 11: 289-293.
- Suryanarayan D1, Schulman S2 (2014) Potential antidotes for reversal of old and new oral anticoagulants. Thromb Res 133 Suppl 2: S158-166.
- Chu C1, Tokumaru S1, Izumi K2, Nakagawa K3 (2016) Obesity increases risk of anticoagulation reversal failure with prothrombin complex concentrate in those with intracranial hemorrhage. Int J Neurosci 126: 62-66.
- Watanabe E1, Yamamoto M2, Kodama I3, Inoue H4, Atarashi H5, et al. (2016) Net clinical benefit of adding aspirin to warfarin in patients with atrial fibrillation: Insights from the J-RHYTHM Registry. Int J Cardiol 212: 311-317.
|Asian Ethnicity||Increasing Age|
|Black Ethnicity||Diastolic Hypertension|
|Presence of Apo-lipoprotein E2 allele||Alcohol Consumption|
|Decreased LDL||Decreased Platelet Count|
Table 1: Predictors of ICH After Oral Anticoagulant Therapy
|Mechanism||II, VII, IX, X||Thrombin||Factor Xa||Factor Xa|
|Antidote||Vit.K||None (PCC/HD)||None (PCC/VIIa)||None (PCC/VIIa)|
|Drug Interaction||Multiple – Cyp2C9||PgpInh.||CYP3A4, Pgp||CYP3A4, Pgp|
Table 2: Pharmacokinetics of Warfarin and Newer Oral Agents
|Lundstrom, 1989 ||Warfarin||213||A.Fib||0.5|
|European AF Trial, 1993 ||Warfarin||225||A.Fib||0|
|AFI 1994 ||Warfarin||1225||A.Fib||0.3|
|SPAF II 1995 ||Warfarin||550||A.Fib||0.9|
|Rocket Trial 2011 ||Rivaroxaban||7111||A.Fib||0.5|
|Engage Trial 2013 ||Edoxaban||7035||A.Fib||0.39|
|Re-Ly Trial 2009 ||Dabigatron||6015||A.Fib||0.3|
|Granger CB et al. 2011 ||Apixaban||9088||A.Fib||0.33|
|Connolly SJ et al. 2011 ||Apixaban||2088||A.Fib||0.4|
Table 3: Intracranial Hemorrhage with Warfarin and Newer Oral Agents
Citation: Visweshwar H (2016) Intracranial Hemorrhage Secondary to Oral Anticoagulant Therapy: Insight into Pathogenesis, Prognosis and Management – A Review. J Hematologica Dis Therapies : JHDT102.