Intracranial hemorrhage and infarction in anticoagulated patients with prosthetic heart valves

Management of anticoagulation in patients with infective endocarditis

Infective endocarditis (IE) carries a high risk of vascular complications (e.g., cerebral embolism, intracerebral hemorrhage, and renal infarction), which are correlated with increased early and late mortality. Although anticoagulation is the cornerstone for management of thromboembolic complications, it remains controversial and challenging in patients with IE. An appropriate anticoagulation strategy is crucial to improving outcomes and requires a good understanding of the indication, timing, and regimen of anticoagulation in the setting of IE. Observational studies have shown that anticoagulant treatment failed to reduce the risk of ischemic stroke in patents with IE, supporting that IE alone is not an indication for anticoagulation. In the absence of randomized controlled trials and high-quality meta-analyses, however, current guidelines on IE were based largely on observational data and expert opinion, providing few specific recommendations on anticoagulation. A multidisciplinary approach and patient engagement are required to determine the timing and regimen of anticoagulation in patients with IE, especially in specific situations (e.g., receiving warfarin anticoagulation at the time of IE diagnosis, cerebral embolism or ischemic stroke, intracerebral hemorrhage, or urgent surgery). Collectively, individualized strategies on anticoagulation management of IE should be based on clinical evaluation, available evidence, and patient engagement, and ultimately be developed by the multidisciplinary team.

Follow-up and management of valvular heart disease patients with prosthetic valve: a clinical practice guideline for Indian scenario

PURPOSE

Valvular heart disease (VHD) patients after prosthetic valve implantation are at risk of thromboembolic events. Follow-up care of patients with prosthetic valve has a paramount role in reducing the morbidity and mortality. Currently, in India, there is quintessential need to stream line the follow-up care of prosthetic valve patients. This mandates the development of a consensus guideline for the antithrombotic therapy in VHD patients post prosthetic valve implantation.

METHODS

A national level panel was constituted comprising 13 leading cardio care experts in India who thoroughly reviewed the up to date literature, formulated the recommendations, and developed the consensus document. Later on, extensive discussions were held on this draft and the recommendations in 8 regional meetings involving 79 additional experts from the cardio care in India, to arrive at a consensus. The final consensus document is developed relying on the available evidence and/or majority consensus from all the meetings.

RESULTS

The panel recommended vitamin K antagonist (VKA) therapy with individualized target international normalized ratio (INR) in VHD patients after prosthetic valve implantation. The panel opined that management of prosthetic valve complications should be personalized on the basis of type of complications. In addition, the panel recommends to distinguish individuals with various co-morbidities and attend them appropriately.

CONCLUSIONS

Anticoagulant therapy with VKA seems to be an effective option post prosthetic valve implantation in VHD patients. However, the role for non-VKA oral therapy in prosthetic valve patients and the safety and efficacy of novel oral anticoagulants in patients with bioprosthetic valve need to be studied extensively.

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.

Intracerebral hemorrhage in patients after heart valve replacement

BACKGROUNDS

Although prevention of hematoma enlargement and thromboembolic complications is critically important in acute intracerebral hemorrhage (ICH) patients with prosthetic heart valves, clinical data are scarce. The goal of this study was to elucidate patient characteristics, acute treatments, and the clinical course of them.

METHODS

We investigated a retrospective cohort of consecutive acute ICH patients with prosthetic heart valves. Neurological data, hospital management, hemorrhagic and thromboembolic complications and functional disability/mortality were reviewed.

RESULTS

We identified 38 patients (27 men; 67.9±16.7 years). The median ICH volume was 22.8 ml. The most frequent location was lobar (50%). All patients with mechanical valves (25/25) and 46% of patients with bioprosthetic valves (6/13) were receiving warfarin at the time of hospital admission. The median anticoagulation withholding period was 2 days in 24 patients who ultimately resumed anticoagulation. Hematoma enlargement within 24 h was observed in eight patients and hemorrhagic complications occurred in three patients. Thromboembolic stroke occurred in four patients. At discharge, death had occurred or severe disability was present in 53% of patients (20/38).

CONCLUSIONS

Hematoma enlargement, hemorrhagic complications or thromboembolic stroke occurred in a significant number of patients during hospitalization. ICH was a serious complication among patients with valve replacement.

Spontaneous Spinal Subdural Hematoma with Simultaneous Cranial Subarachnoid Hemorrhage

Spontaneous spinal subdural hematoma is reported at a rare level of incidence, and is frequently associated with underlying coagulopathy or those receiving anticoagulant or antiplatelet agents; some cases accompany concomitant intracranial hemorrhage. The spontaneous development of spinal subdural hemorrhage (SDH) is a neurological emergency; therefore, early diagnosis, the discontinuation of anticoagulant, and urgent surgical decompression are required to enable neurological recovery. In this report, we present a simultaneous spinal subdural hematoma and cranial subarachnoid hemorrhage, which mimicked an aneurysmal origin in a female patient who had been taking warfarin due to aortic valve replacement surgery.

Mycotic aneurysm detection rates with cerebral angiography in patients with infective endocarditis

BACKGROUND

Cerebral angiography remains the gold standard for the detection of mycotic aneurysms, and it has been estimated that ruptured mycotic aneurysms result in 5% of the neurological complications of patients with infective endocarditis (IE).

OBJECTIVE

To determine the diagnostic yield of cerebral angiography in the above patient population and to assess patient factors that might suggest greater or lesser utility.

METHODS

We retrospectively reviewed 168 patients who underwent cerebral angiography with a diagnosis of IE or infected left ventricular assist device at the Cleveland Clinic between January 2003 and March 2010 in accordance with institutional review board guidelines. Chart and imaging review was performed.

RESULTS

15/168 patients (8.9%) had mycotic aneurysms; 93.3% (14/15) of the patients with mycotic aneurysms presented with CNS hemorrhage and 66.7% (10/15) had acute ischemic findings. Of the 15 patients with mycotic aneurysms on angiography, seven underwent CT angiography and six underwent MR angiography, which showed mycotic aneurysms in three (42.9%) and two cases (one of which was questionable; 33.3%), respectively.

CONCLUSIONS

Patients with IE or similar sources of central bacterial emboli are prone to neurovascular complications. Approximately 9% of patients with IE at our institution who undergo cerebral angiography have mycotic aneurysms. Presentation with hemorrhage appears to be more predictive of aneurysm, as approximately 22% of patients with IE and hemorrhage were found to have an aneurysm compared with only 1% when hemorrhage was absent. Thus, patients with IE presenting with intracranial hemorrhage should undergo vascular imaging, preferably with cerebral angiography.

Prosthetic valve endocarditis: what is the evidence for anticoagulant therapy?

The use of anticoagulant therapy in prosthetic valve endocarditis is a controversial management issue. Some authorities believe that anticoagulation increases the potential risk of cerebral haemorrhage after a thromboembolism whereas others, however, affirm that cessation of anticoagulation itself increases the risk of thromboembolism and subsequent morbidity and mortality. We reviewed the association of anticoagulant therapy and cerebral complications in patients with prosthetic valve endocarditis. Our results suggest that anticoagulant therapy reduces the risk of thromboembolism and is not associated with increased risk of intracranial haemorrhage.

Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Antithrombotic therapy in valvular disease is important to mitigate thromboembolism, but the hemorrhagic risk imposed must be considered.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

In rheumatic mitral disease, we recommend vitamin K antagonist (VKA) therapy when the left atrial diameter is > 55 mm (Grade 2C) or when complicated by left atrial thrombus (Grade 1A). In candidates for percutaneous mitral valvotomy with left atrial thrombus, we recommend VKA therapy until thrombus resolution, and we recommend abandoning valvotomy if the thrombus fails to resolve (Grade 1A). In patients with patent foramen ovale (PFO) and stroke or transient ischemic attack, we recommend initial aspirin therapy (Grade 1B) and suggest substitution of VKA if recurrence (Grade 2C). In patients with cryptogenic stroke and DVT and a PFO, we recommend VKA therapy for 3 months (Grade 1B) and consideration of PFO closure (Grade 2C). We recommend against the use of anticoagulant (Grade 1C) and antiplatelet therapy (Grade 1B) for native valve endocarditis. We suggest holding VKA therapy until the patient is stabilized without neurologic complications for infective endocarditis of a prosthetic valve (Grade 2C). In the first 3 months after bioprosthetic valve implantation, we recommend aspirin for aortic valves (Grade 2C), the addition of clopidogrel to aspirin if the aortic valve is transcatheter (Grade 2C), and VKA therapy with a target international normalized ratio (INR) of 2.5 for mitral valves (Grade 2C). After 3 months, we suggest aspirin therapy (Grade 2C). We recommend early bridging of mechanical valve patients to VKA therapy with unfractionated heparin (DVT dosing) or low-molecular-weight heparin (Grade 2C). We recommend long-term VKA therapy for all mechanical valves (Grade 1B): target INR 2.5 for aortic (Grade 1B) and 3.0 for mitral or double valve (Grade 2C). In patients with mechanical valves at low bleeding risk, we suggest the addition of low-dose aspirin (50-100 mg/d) (Grade 1B). In valve repair patients, we suggest aspirin therapy (Grade 2C). In patients with thrombosed prosthetic valve, we recommend fibrinolysis for right-sided valves and left-sided valves with thrombus area < 0.8 cm(2) (Grade 2C). For patients with left-sided prosthetic valve thrombosis and thrombus area ≥ 0.8 cm(2), we recommend early surgery (Grade 2C).

CONCLUSIONS

These antithrombotic guidelines provide recommendations based on the optimal balance of thrombotic and hemorrhagic risk.

Survey of neurosurgical management of central nervous system hemorrhage in patients receiving anticoagulation therapy: current practice is highly variable and may be suboptimal

BACKGROUND

Patients with central nervous system (CNS) hemorrhage who receive anticoagulation (AC) therapy are at high risk for progressive or recurrent hemorrhagic and thromboembolic (TE) events. The authors conducted a survey at the 2010 American Association of Neurological Surgeons (AANS) annual meeting to determine how these patients are currently being managed by neurosurgeons.

METHODS

During plenary session III at the 2010 AANS annual meeting, the audience was presented with an illustrative case and surveyed with an audience response system. The number choosing each response as well as data regarding the level of training of meeting registrants were provided to the authors by the AANS.

RESULTS

Approximately 10% of all meeting registrants responded to the questions, 65% of whom were consultant neurosurgeons. The responses showed that 47.7% of respondents face dilemmas regarding AC restart time and intensity at least once per week. The most commonly selected AC restart time was 1 month after the index hemorrhage (43.5%); 8.0% indicated they would not restart AC. In making management decisions in these patients, 59.4% of respondents indicated that they relied predominantly on their own intuition or past experience.

CONCLUSIONS

This study is the first to describe how patients with CNS hemorrhage who receive AC therapy are currently being managed by clinicians. An apparent neurosurgical preference to avoid hemorrhagic complications is at odds with a suggested early risk for TE. These data suggest that the neurosurgical management of patients with CNS hemorrhage who receive AC therapy is an area that could benefit from consensus-based practice guidelines and an organized effort at knowledge translation and mobilization.

Antithrombotic therapy in cardiac embolism

Anticoagulation is indicated in most cardioembolic ischemic strokes for secondary prevention. In many cardiac conditions, anticoagulation is also indication for primary stroke prevention, mainly when associated to vascular risk factors. Anticoagulation should be started as soon as possible, as it is safe even in moderate acute strokes. The efficacy of early anticoagulation after cardioembolic stroke in relation to outcome has not been assessed adequately, but there is evidence from animal models and clinical studies that anticoagulation with unfractionated heparin is associated with a better outcome mediated in part by its anti-inflammatory properties.

Management of anticoagulation following central nervous system hemorrhage in patients with high thromboembolic risk

SUMMARY BACKGROUND

Patients who present with central nervous system (CNS) hemorrhage while on anticoagulation (AC) for thromboembolic (TE) risk factors are a challenge to manage.

OBJECTIVE

We sought to inform decisions surrounding the timing and intensity of AC resumption by performing a systematic review.

METHODS

Three reviewers screened publications from Medline and EMBASE and extracted data. Hemorrhagic and TE adverse events that occurred subsequent to the index hemorrhage were recorded, as was their timing relative to presentation and covariates that might influence their occurrence.

RESULTS

Data were extracted from 63 publications detailing 492 patients; 7.7% of patients experienced hemorrhagic complications and 6.1% experienced TE complications. Hemorrhagic complications were more common within 72 h of presentation while TE complications were more common thereafter. Patients restarted on AC after 72 h were significantly more likely to have a TE complication (P = 0.006) and those restarted before 72 h were more likely to hemorrhage (P = 0.0727). Factors associated with re-hemorrhage included younger age, traumatic cause, subdural hematomas and failure to reverse AC. TE complications were more common in younger patients and those with spinal hemorrhage, multiple hemorrhages, and non-traumatic causes of the index hemorrhage. Re-initiation of AC at a lower intensity also significantly increased the risk of TE complications.

INTERPRETATION

Our results suggest that it may be prudent to re-initiate AC earlier than previously thought, with the timing and intensity modified based on predictors of TE and hemorrhagic complications. These findings must be explored in a prospective study because of limitations inherent to the analyzed studies.

Systematic review of observational research studying the long-term use of antithrombotic medicines following intracerebral hemorrhage

Patients with intracerebral hemorrhage frequently have indications for antithrombotic therapy. This represents a therapeutic dilemma as intracerebral hemorrhage is considered a contraindication to antithrombotic medication. Previous systematic reviews have revealed no long-term randomised studies addressing this issue. Our objective was to review observational studies describing the long-term follow-up of patients receiving antithrombotic therapy following intracerebral hemorrhage. Searches were conducted in MEDLINE and EMBASE from 1984 to 2008 for any observational studies detailing use of antithrombotic treatments in patients with intracerebral hemorrhage. Included studies must have had follow-up extending beyond discharge. The primary endpoint was recurrent intracerebral hemorrhage. Secondary endpoints were ischemic events and serious vascular events. 1,301 articles were reviewed: two epidemiological studies and six case series met the inclusion criteria. These described a total of 46 subjects receiving antiplatelet agents (from one study) and 42 patients receiving oral anticoagulants (from one study and six case-series). For patients receiving subsequent aspirin there were seven recurrent intracerebral hemorrhages and four subsequent thrombo-occulsive events. Amongst patients restarting oral anticoagulation there were four recurrent intracerebral bleeds and nine subsequent thrombo-occulsive events. There is a marked paucity of evidence to guide clinicians when planning the long-term management of patients with intracerebral hemorrhage and cogent indications for antithrombotic therapy. Published guidance addressing this issue is not evidence based. In the continued absence of randomised studies addressing antithrombotic use following intracerebral hemorrhage, there is a clear requirement for further high quality observational data on the clinical impact of antithrombotic therapy in this important patient group.

The outcome of patients with transient ischemic attacks and stroke treated with anticoagulants

Long-term anticoagulant treatment was given to 25 patients with transient ischemic attacks (TIA) and 49 stroke patients with reversible ischemic neurological deficit or cerebral embolism. Another 16 TIA patients were observed without anticoagulant treatment. Life table analyses, comparing the observed with the expected frequency, revealed increased mortality in the TIA patients irrespective of whether or not they had received anticoagulants. The stroke patients treated with anticoagulants also had a higher mortality than expected. On the other hand, the incidence of subsequent stroke was not higher than expected in the TIA and stroke patients treated with anticoagulants, while it was significantly increased in the TIA patients not treated with anticoagulants. Thus, the risk of stroke, but not the risk of death, was normalized by the anticoagulant treatment. Unacceptably serious bleeding complications were seen in the group of stroke patients with anticoagulant treatment. Bleeding complications, in both TIA and stroke patients, seemed to be related to lengthy treatment, high blood pressure on admission or insufficient patient compliance.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

Spontaneous intracerebral hemorrhage due to coagulation disorders

Although intracranial hemorrhage accounts for approximately 10 to 15% of all cases of stroke, it is associated with a high mortality rate. Bleeding disorders account for a small but significant risk factor associated with intracranial hemorrhage. In conditions such as hemophilia and acute leukemia associated with thrombocytopenia, massive intracranial hemorrhage is often the cause of death. The authors present a comprehensive review of both the physiology of hemostasis and the pathophysiology underlying spontaneous ICH due to coagulation disorders. These disorders are divided into acquired conditions, including iatrogenic and neoplastic coagulopathies, and congenital problems, including hemophilia and rarer diseases. The authors also discuss clinical features, diagnosis, and management of intracranial hemorrhage resulting from these bleeding disorders.

Restarting anticoagulation in prosthetic heart valve patients after intracranial haemorrhage: a 2-year follow-up

35 patients with oral anticoagulant (OAC) related intracranial or intraspinal haemorrhage were studied to determine treatment received, outcome and rate of recurrent bleeding and thromboembolism after restarting OAC. All patients underwent active anticoagulant reversal and in 14 patients with prosthetic heart valves (PHV) the INR remained below 2.0 for 0-19d (median 7) with no thromboembolic events. 10 patients received heparin, although a therapeutic level was rarely achieved. 13 patients with PHV were restarted on OAC and followed for a median 23.5 months. One patient had recurrent intracranial bleeding. 3/13 patients had cerebral embolic events despite anticoagulation. We conclude that in PHV patients temporary cessation of OAC is safe and the risk of recurrent bleeding after restarting OAC is low.

The dilemma of discontinuation of anticoagulation therapy for patients with intracranial hemorrhage and mechanical heart valves

BACKGROUND

Anticoagulant-related hemorrhage occurs with an incidence of approximately 1%/patient-year in mechanical heart valve recipients. Intracranial hemorrhage poses a difficult clinical choice; continuing anticoagulation therapy may enlarge the volume of the hemorrhage, early reinstitution of anticoagulation therapy may predispose patients to recurrence, and reversal of anticoagulation therapy may place patients at risk for systemic embolization involving the brain. The risk of embolization may also be greater for patients with atrial fibrillation, cage-ball valves in the mitral position, and reduced ventricular function. This dilemma exists because of a lack of data for a large series of patients.

METHODS

We reviewed the medical records and neuroimaging studies for a consecutive group of patients admitted with intracranial hemorrhage and mechanical heart valves. We reviewed neurological presenting data, cardiac risk factors for systemic embolization (atrial fibrillation, enlarged atrial chambers, reduced ventricular function, and the type and location of the metallic valve), and hospital management.

RESULTS

We studied 39 patients with intracranial hemorrhage and mechanical heart valves (median age, 69 yr). Four patients had experienced previous transient ischemic attacks or minor strokes. The time from valve replacement to intracranial hemorrhage ranged from 2 months to 19 years (median, 6 yr). The type of intracranial hemorrhage was acute subdural hematoma (n = 20), lobar hematoma (n = 10), subarachnoid hemorrhage (n = 4), cerebellar hematoma (n = 3), or basal ganglionic hematoma (n = 2). Thirteen patients died within 2 days of admission. All 26 surviving patients received fresh frozen plasma and vitamin K. Fifteen patients underwent evacuation of acute subdural hematoma, and in one patient an anterior communicating aneurysm was clipped. The duration of discontinuation of anticoagulation therapy varied from 2 days to 3 months (median, 8 d). None of the patients developed transient ischemic attacks, ischemic strokes, valve thrombosis, or systemic embolization. No recurrence of intracranial hemorrhaging was observed during hospitalization and reinstitution of anticoagulation or antiplatelet agent administration.

CONCLUSION

Temporary interruption of anticoagulation therapy seems safe for patients with intracranial hemorrhage and mechanical heart valves but without previous evidence of systemic embolization. For most patients, discontinuation for 1 to 2 weeks should be sufficient to observe the evolution of a parenchymal hematoma, to clip or coil a ruptured aneurysm, or to evacuate an acute subdural hematoma.

Management of oral anticoagulant-induced intracranial haemorrhage

Intracranial haemorrhage is an infrequent but often fatal complication of oral anticoagulant therapy which will become more common as anticoagulant use increases. The risk of anticoagulant-induced intracranial haemorrhage may be reduced by judicious prescribing, identification of patients at high risk of bleeding, and close monitoring by experienced staff. The presenting features of intracranial haemorrhage are often vague and physicians should be aware of the need for urgent investigation of all anticoagulated patients with neurological symptoms. Current guidelines for immediate reversal of anticoagulation recommend administration of vitamin K1 and factor replacement with either factor concentrates or fresh frozen plasma. In this review we discuss recent evidence suggesting prothrombin complex concentrates lead to faster, and more complete, correction of coagulation and, in the context of intracranial bleeding, may be associated with improved neurological status. Evidence for the risks of short-term cessation of anticoagulants, in the immediate period following an intracranial haemorrhage, and their subsequent reintroduction is also discussed.

Management of intracranial hemorrhage associated with anticoagulant therapy

BACKGROUND

Intracranial hemorrhage may be a particularly devastating complication of anticoagulant therapy. Very few accounts have reported data on the duration of anticoagulant discontinuation following intracranial hemorrhage or the intensity of anticoagulation during treatment for it, although we must adequately manage such a complication.

METHODS

We analyzed the management of warfarin-related intracranial hemorrhages in 27 patients with cardiac diseases. We evaluated the degree of anticoagulation using the thrombotest. Anticoagulants were stopped as soon as the diagnosis of intracranial hemorrhage was established by computed tomographic scan.

RESULTS

Mechanical valve prosthesis patients, who required intensive long-term anticoagulant therapy, constituted the majority of our series (74.1%). Intraoperative hemostasis was brought under control despite low thrombotest values (13%-68%) at the time of surgery except for the acute subdural hematoma (SDH) patients with cerebral contusion. Early resumption of anticoagulant therapy (within 3 days) did not cause intracranial rebleeding in any operative patient. All the chronic SDH patients and some of the subcortical hematoma patients had a good outcome. All three patients with acute SDH and contusion, however, had a fatal outcome because of intracranial rebleeding within a short period of time or ineffective intraoperative hemostasis.

CONCLUSIONS

The patients with anticoagulant-related intracranial hemorrhage may undergo surgery with thrombotest values approximately between 20% and 60%, and anticoagulants can be resumed after an interval of 3 days. Aggressive surgery should particularly be performed in patients with anticoagulation-related chronic SDH or subcortical hemorrhage, as in the cases of anticoagulant-unrelated intracranial hemorrhage.

Ruptured intracranial mycotic aneurysm: a rare cause of intracranial hemorrhage

Intracranial mycotic aneurysm is a rare complication in patients with infective endocarditis occurring in about 2% to 10% of cases. Although the risk of rupture is about 1.7%, it is usually a catastrophic event with a fatality rate of 80%. Neurological deficits secondary to cortical involvement are common, given the frequency of intralobar hemorrhage. We report two cases of intracerebral hemorrhage caused by ruptured intracranial mycotic aneurysms. Both had involvement of the right frontoparietal lobes with resultant left hemiparesis, left homonymous hemianopia, and impairments of cognition and perceptual function. Despite intensive rehabilitation, their functional outcomes were less than satisfactory as they needed assistance in self-care activities and mobility on discharge.

Intracranial hemorrhage after coronary thrombolysis with tissue plasminogen activator

PURPOSE AND METHODS

We analyzed the clinical, laboratory, and radiologic data in nine patients who sustained an intracranial hemorrhage (ICH) after receiving intravenous recombinant tissue plasminogen activator (rt-PA) and heparin for treatment of acute myocardial infarction (MI). Our purpose was to delineate the clinical and radiologic features of the ICHs, as well as to determine their potential risk factors and mechanisms.

RESULTS

Among 1,700 patients with an acute MI treated with an investigational two-chain rt-PA, duteplase (Burroughs Wellcome Co., Research Triangle Park, NC), nine (0.53%) developed symptomatic ICH. Neurologic symptoms occurred between 7 and 96 hours after onset of rt-PA therapy. All patients received heparin concomitantly for prevention of coronary reocclusion. The activated partial thromboplastin times (aPTTs) in five of eight (63%) patients at onset of ICH were excessively prolonged (greater than two times control); hypofibrinogenemia occurred in only one of five (20%) patients tested; and thrombocytopenia was present in only one of the nine (11%) patients. Fibrin degradation products (FDPs) were elevated in all five patients tested. Minor hemorrhage (not requiring transfusion) outside the central nervous system occurred in five of the nine patients with ICH. The ICHs were often of lobar location and of moderate to large size. They occurred at multiple sites in three patients, and were fatal in four instances (44%).

CONCLUSIONS

The incidence of ICH in this series was low, and consistent with figures reported from studies with alteplase in patients with acute MI. The mechanisms of these hemorrhages remain unclear; while hypofibrinogenemia was not a uniform finding, excessive prolongation of the aPTT and elevated FDPs may have contributed to the occurrence of ICH in some patients. Still unidentified local cerebrovascular factors may play an additional role in causing ICH. In order to further clarify the mechanisms of ICH in the setting of thrombolytic therapy, prospective data collection on probable risk factors for ICH in patients with acute MI treated with rt-PA will be required.

Heparin treatment in sinus venous thrombosis

Treatment of sinus venous thrombosis (SVT) is controversial. Although heparin has been used for this condition, many investigators have opposed its use because of the frequent occurrence of intracranial haemorrhage (ICH) and SVT. Therefore we have evaluated anticoagulation with adjusted-dose intravenous heparin for treatment of aseptic SVT in a randomised, blinded (patient and observer), placebo-controlled study in 20 patients (10 heparin, 10 placebo). The clinical course of the two groups, as judged by a newly designed SVT-severity scale, started to differ in favour of the heparin group after 3 days of treatment (p less than 0.05, Mann-Whitney U-test) and the difference remained significant (p less than 0.01) after 8 days of treatment. After 3 months, 8 of the heparin-treated patients had a complete clinical recovery and 2 had slight residual neurological deficits. In the placebo group, only 1 patient had a complete recovery, 6 patients had neurological deficits, and 3 patients died (p less than 0.01, modified Fisher's exact test). An additional retrospective study on the relation between heparin treatment and ICH in SVT patients was based on 102 patients, 43 of whom had an ICH. 27 of these patients were treated with dose-adjusted, intravenous heparin after the ICH. Of these 27 patients, 4 died (mortality 15%), and 14 patients completely recovered. Of the 13 patients that did not receive heparin after ICH, 9 died (mortality 69%) and only 3 patients completely recovered. We conclude that anticoagulation with dose-adjusted intravenous heparin is an effective treatment in patients with SVT and that ICH is not a contraindication to heparin treatment in these patients.

Perioperative stroke. Part II: Cardiac surgery and cardiogenic embolic stroke

The major mechanism of stroke in cardiac surgery is embolization. The risk is higher in intracardiac than in extracardiac surgery. The incidence of stoke associated with CABG is about 5%. The cerebral protective properties of isoflurane and thiopentone, acid-base management, and monitoring of cerebral perfusion during cardiopulmonary bypass are discussed. Prophylactic carotid endarterectomy for patients with asymptomatic carotid disease before cardiac surgery is not necessary. Symptomatic carotid disease increases the risk of stroke, and the management of patients who have both symptomatic coronary and carotid artery diseases is discussed. Cardiogenic embolism is probably responsible for many perioperative strokes. Patients with atrial fibrillation, valvular disease, and prosthetic heart valves are at high risk of cardiogenic embolism. Strokes associated with cardioversion, pacemaker insertion, coronary arteriography and angioplasty are explored.

Cerebral haemorrhage in anticoagulated patients with non-septic mechanical valvular prosthesis

Cerebral haemorrhage in anticoagulated patients with mechanical valvular prosthesis poses an uncommon but difficult management problem. Four such patients are presented: one patient had delayed haemorrhagic transformation of a preexisting cerebral infarct, one probably had de novo haemorrhage complicating hypertension and in two patients cerebral haemorrhage was associated with excessive anticoagulation. Conservative management including the use of fresh frozen plasma, delayed heparinisation and warfarinisation was used. Both patients with anticoagulant overdose died as a result of extensive haemorrhage despite the drainage of cerebellar haematoma in one patient. The remaining two patients survived with minimal neurological deficits. Diagnosis of the underlying cause of cerebral haemorrhage, and the timing of heparinisation and anticoagulation are discussed.

Neurologic complications of late prosthetic valve endocarditis

We reviewed the records of 20 patients with late prosthetic valve endocarditis who were hospitalized at the University of Iowa between 1985 and 1988. There were 14 men and six women, aged 20-80 (mean 57.9) years. The infected valves were mechanical in 11 patients (six aortic and five mitral) and bioprosthetic in the other nine. Echocardiography in 12 patients demonstrated vegetations in one. Among the 20 patients, neurologic complications occurred in eight (40%), six of whom had mechanical valves (five mitral and one aortic). Infection with Staphylococcus aureus occurred in four of the eight patients (50%) with neurologic complications. Of the eight patients with neurologic complications, ischemic stroke was diagnosed in four, transient ischemic attacks in one, and intracranial hemorrhage in three. Prothrombin times at the time of the intracranial hemorrhage were 2.2, 1.5, and 1.3 times control in these three patients. Cerebral angiography done in four of the eight patients with neurologic complications failed to show mycotic aneurysms. Nine of the 20 patients (seven men and two women, mean age 66.8 years) died less than or equal to 90 days after the diagnosis of late prosthetic valve endocarditis. Half of the eight patients with neurologic complications died (three men and one woman, mean age 62.3 years), and all three patients with intracranial hemorrhage died. Our data suggest that the neurologic complications of late prosthetic valve endocarditis are more common with mechanical valves, particularly in the mitral position, and are associated with a high mortality.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.

Anticoagulant therapy in recurrent cerebral embolism: a retrospective study in non-valvular atrial fibrillation

For the prevention of recurrent embolic stroke, 23 elderly patients with non-valvular atrial fibrillation (NVAF) were treated with oral anticoagulants (warfarin) during a mean period of 3.8 years. Only one patient suffered recurrent embolism, and another had acute myocardial infarction. There was no cerebral haemorrhage during the treatment. In an untreated control group (from an autopsy series), recurrent embolic strokes occurred in 18 of 70 NVAF patients (26%) during a mean period of 1.3 years. Long-term anticoagulant therapy appears to be effective in the prevention of recurrent embolic stroke in elderly patients with NVAF.

Thrombotic and bleeding complications of prosthetic heart valves

A review of articles published since 1979 indicates that thrombotic and bleeding complications account for about 50% of valve-related complications in patients with bioprosthetic aortic and mitral valves and for approximately 75% of the complications in patients with mechanical valves. Although compromised by lack of standard definitions and by variability in reporting and follow-up, the data suggest that the linearized rate of both thrombotic and bleeding complications in patients with aortic bioprostheses is approximately half that for aortic mechanical prostheses (2% versus 4%), but is approximately equal for both bioprostheses and mechanical valves in the mitral position (approximately 4%), and for mechanical and bioprosthetic aortic and mitral valves in combination. However, linearized rates for fatal thrombotic and bleeding events are two to four times higher in patients with mechanical prostheses. The adequacy of warfarin anticoagulation is the most important factor affecting thrombotic and bleeding complications in patients with mechanical valves and over shadows the dubious importance of other phenomena such as atrial fibrillation and left atrial thrombus. Short-term warfarin anticoagulation or the use of long-term platelet inhibitors, or both, do not appear to reduce the incidence of thrombotic complications in patients with aortic bioprostheses but increase bleeding. For mitral bioprostheses, the postoperative use of warfarin for three months or aspirin indefinitely is as effective in preventing thromboembolism as long-term warfarin. Acute prosthetic valve endocarditis is associated with a 13 to 40% incidence of thrombotic complications. Likewise, the recurrence rate of cerebral emboli is high (20-30%) in patients with prosthetic valves who are not anticoagulated. Bioprostheses are strongly preferred for women who wish to bear children; fetal wastage occurs in 25 to 30% of pregnant women with mechanical heart valves who receive either warfarin or heparin, or a combination of the two. Heparin, however, greatly increases the risk of maternal bleeding. In children, the efficacy of platelet inhibitors without warfarin anticoagulation is unproven; nearly all serious strokes occur when warfarin is omitted; and permanent disability from warfarin-related bleeding is rare. All prosthetic cardiac valves initiate coagulation and affect the dynamic equilibrium between activated procoagulants and endogenous anticoagulants. Warfarin is the only available oral exogenous anticoagulant.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk of early anticoagulation in patients with small deep infarcts possibly caused by cardiogenic emboli

From a prospective registry of 103 stroke patients on early anticoagulation for cardiac embolus we selected 23 patients with a small deep infarct. We studied the incidence of hemorrhagic infarction on CT, and the risk of early anticoagulation. We found no hemorrhagic infarction on CT in any case, and no bleeding complications during the three week observation period. Obviously, early anticoagulation can be started safely in patients with a small deep infarct possibly caused by cardiac embolism.