Antifibrinolytic treatment in subarachnoid haemorrhage: present state

Antifibrinolytic therapy for aneurysmal subarachnoid haemorrhage

BACKGROUND

Rebleeding is an important cause of death and disability in people with aneurysmal subarachnoid haemorrhage. Rebleeding is probably related to the dissolution of the blood clot at the site of the aneurysm rupture by natural fibrinolytic activity. This review is an update of previously published Cochrane Reviews.

OBJECTIVES

To assess the effects of antifibrinolytic treatment in people with aneurysmal subarachnoid haemorrhage.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (May 2022), CENTRAL (in the Cochrane Library 2021, Issue 1), MEDLINE (December 2012 to May 2022), and Embase (December 2012 to May 2022). In an effort to identify further published, unpublished, and ongoing studies, we searched reference lists and trial registers, performed forward tracking of relevant references, and contacted drug companies (the latter in previous versions of this review).

SELECTION CRITERIA

Randomised trials comparing oral or intravenous antifibrinolytic drugs (tranexamic acid, epsilon amino-caproic acid, or an equivalent) with control in people with subarachnoid haemorrhage of suspected or proven aneurysmal cause.

DATA COLLECTION AND ANALYSIS

Two review authors (MRG & WJD) independently selected trials for inclusion, and extracted the data for the current update. In total, three review authors (MIB & MRG in the previous update; MRG & WJD in the current update) assessed risk of bias. For the primary outcome, we dichotomised the outcome scales into good and poor outcome, with poor outcome defined as death, vegetative state, or (moderate) severe disability, assessed with either the Glasgow Outcome Scale or the Modified Rankin Scale. We assessed death from any cause, rates of rebleeding, delayed cerebral ischaemia, and hydrocephalus per treatment group. We expressed effects as risk ratios (RR) with 95% confidence intervals (CI). We used random-effects models for all analyses. We assessed the quality of the evidence with GRADE.

MAIN RESULTS

We included one new trial in this update, for a total of 11 included trials involving 2717 participants. The risk of bias was low in six studies. Five studies were open label, and we rated them at high risk of performance bias. We also rated one of these studies at high risk for attrition and reporting bias.  Five trials reported on poor outcome (death, vegetative state, or (moderate) severe disability), with a pooled risk ratio (RR) of 1.03 (95% confidence interval (CI) 0.94 to 1.13; P = 0.53; 5 trials, 2359 participants; high-quality evidence), which showed no difference between groups. All trials reported on death from all causes, which showed no difference between groups, with a pooled RR of 1.02 (95% CI 0.90 to 1.16; P = 0.77; 11 trials, 2717 participants; high-quality evidence). In trials that combined short-term antifibrinolytic treatment (< 72 hours) with preventative measures for delayed cerebral ischaemia, the RR for poor outcome was 0.98 (95% CI 0.81 to 1.18; P = 0.83; 2 trials, 1318 participants; high-quality evidence).  Antifibrinolytic treatment reduced the risk of rebleeding, reported at the end of follow-up (RR 0.65, 95% CI 0.47 to 0.91; P = 0.01; 11 trials, 2717 participants; absolute risk reduction 7%, 95% CI 3 to 12%; moderate-quality evidence), but there was heterogeneity (I² = 59%) between the trials. The pooled RR for delayed cerebral ischaemia was 1.27 (95% CI 1.00 to 1.62; P = 0.05; 7 trials, 2484 participants; moderate-quality evidence). However, this effect was less extreme after the implementation of ischaemia preventative measures and < 72 hours of treatment (RR 1.10, 95% CI 0.83 to 1.46; P = 0.49; 2 trials, 1318 participants; high-quality evidence). Antifibrinolytic treatment showed no effect on the reported rate of hydrocephalus (RR 1.09, 95% CI 0.99 to 1.20; P = 0.09; 6 trials, 1992 participants; high-quality evidence).

AUTHORS' CONCLUSIONS

The current evidence does not support the routine use of antifibrinolytic drugs in the treatment of people with aneurysmal subarachnoid haemorrhage. More specifically, early administration with concomitant treatment strategies to prevent delayed cerebral ischaemia does not improve clinical outcome. There is sufficient evidence from multiple randomised controlled trials to incorporate this conclusion in treatment guidelines.

Prevention of Early Recurrence of Aneurysmal Subarchnoid Haemorrhage by Tranexamic Acid: A Controlled Clinical Trial

A controlled clinical trial of Tranexamic Acid (TEA) was underaken to as sess its effectiveness in reducing early recurrence of haemorrhage in patients with aneurysmal subarchnoid haemorrhge (SAH). The series of control patients and patients having TEA which were consecutive. Of the 65 patients treated with TEA recurrence occurred in six (9%) and five patients died from recur rence of haemorrhage. Of the 64 patients in the control group, 17 (26%) pa tients had recurrent haemorrhage and eight patients died from it. Administra tion of tranexamic acid is found to have significantly reduced the early recur rence of haemorrhage.

Antifibrinolytic therapy for aneurysmal subarachnoid haemorrhage

BACKGROUND

Rebleeding is an important cause of death and disability in people with aneurysmal subarachnoid haemorrhage. Rebleeding is probably related to dissolution of the blood clot at the site of aneurysm rupture by natural fibrinolytic activity. This review is an update of a previously published Cochrane review.

OBJECTIVES

To assess the effects of antifibrinolytic treatment in people with aneurysmal subarachnoid haemorrhage.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (February 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (1948 to December 2012), and EMBASE (1947 to December 2012). In an effort to identify further published, unpublished, and ongoing studies we searched reference lists and trial registers, performed forward tracking of relevant references and contacted drug companies.

SELECTION CRITERIA

Randomised trials comparing oral or intravenous antifibrinolytic drugs (tranexamic acid, epsilon amino-caproic acid, or an equivalent) with control in people with subarachnoid haemorrhage of suspected or proven aneurysmal cause.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted the data. Three review authors assessed trial quality. For the primary outcome we converted the outcome scales between good and poor outcome for the analysis. We scored death from any cause and rates of rebleeding, cerebral ischaemia, and hydrocephalus per treatment group. We expressed effects as risk ratios (RR) with 95% confidence intervals (CI). We used random-effects models for all analyses.

MAIN RESULTS

We included 10 trials involving 1904 participants. The risk of bias was low in six studies. Four studies were open label and were rated as high risk of performance bias. One of these studies was also rated as high risk for attrition bias. Four trials reported on poor outcome (death, vegetative state, or severe disability) with a pooled risk ratio (RR) of 1.02 (95% confidence interval (CI) 0.91 to 1.15). All trials reported on death from all causes with a pooled RR of 1.00 (95% CI 0.85 to 1.18). In a trial that combined short-term antifibrinolytic treatment (< 72 hours) with preventative measures for cerebral ischaemia the RR for poor outcome was 0.85 (95% CI 0.64 to 1.14). Antifibrinolytic treatment reduced the risk of re-bleeding reported at the end of follow-up (RR 0.65, 95% CI 0.44 to 0.97; 78 per 1000 participants), but there was heterogeneity (I² = 62%) between the trials. The pooled RR for reported cerebral ischaemia was 1.41 (95% CI 1.04 to 1.91, 83 per 1000 participants), again with heterogeneity between the trials (I² = 52%). Antifibrinolytic treatment showed no effect on the reported rate of hydrocephalus in five trials (RR 1.11, 95% CI 0.90 to 1.36).

AUTHORS' CONCLUSIONS

The current evidence does not support the use of antifibrinolytic drugs in the treatment of people with aneurysmal subarachnoid haemorrhage, even in those who have concomitant treatment strategies to prevent cerebral ischaemia. Results on short-term treatment are promising, but not conclusive. Further randomised trials evaluating short-term antifibrinolytic treatment are needed to evaluate its effectiveness.

Antifibrinolytic therapy for aneurysmal subarachnoid haemorrhage

BACKGROUND

Rebleeding is an important cause of death and disability in people with aneurysmal subarachnoid haemorrhage. Rebleeding is probably due to dissolution of the clot by natural fibrinolytic activity.

OBJECTIVES

The objective of this review was to assess the effect of antifibrinolytic treatment in patients with aneurysmal subarachnoid haemorrhage.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register, the Cochrane Controlled Trials Register, Medline and Embase (last searched June 2002) and reference lists of articles. We also contacted drug companies.

SELECTION CRITERIA

Randomised trials comparing oral or intravenous antifibrinolytic drugs (tranexamic acid, epsilon amino-caproic acid or an equivalent) with control in people with confirmed subarachnoid haemorrhage.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion and extracted the data. All five reviewers assessed trial quality.

MAIN RESULTS

Nine trials involving 1399 patients were included. Based on 1041 patients in three trials, antifibrinolytic treatment did not show any evidence of benefit for poor outcome (death, vegetative state or severe disability) with an odds ratio of 1.12, 95% confidence interval 0.88 to 1.43. Death from all causes was not significantly influenced by treatment across all nine trials (odds ratio 0.99, 95% confidence interval 0.79 to 1.24). Antifibrinolytic treatment reduced the risk of re-bleeding reported at the end of follow-up, with some heterogeneity between the trials (odds ratio 0.55, 95% confidence interval 0.42 to 0.71). Treatment increased the risk of cerebral ischaemia in five trials (odds ratio 1.39, 95% confidence interval 1.07 to 1.82) with considerable heterogeneity between the most recent study (Roos 2000), in which specific treatments to prevent cerebral ischemia were used, and the four older studies. Antifibrinolytic treatment showed no effect on the reported rate of hydrocephalus in five trials (odds ratio 1.14, 95% confidence interval 0.86 to 1.51).

REVIEWER'S CONCLUSIONS

Treatment does not improve clinical outcome because the benefit is offset by an increase in poor outcome caused by cerebral ischemia as a result of treatment with antifibrinolytics. These data do not support the routine use of antifibrinolytic drugs in the treatment of patients with aneurysmal subarachnoid haemorrhage.

Hemostatic Drugs in Prothrombotic or Hypercoagulable States

Certain drug therapies, such as heparin, warfarin, and aspirin, are associated with prothrombotic or hypercoagulable states. If these agents that are administered to prevent thrombosis have been associated with its opposite effect, then agents that are specifically given to inhibit bleeding may produce a deleterious hypocoagulable effect. This article evaluates the risks presented by serine protease inhibitors (ie, aprotinin), lysine analog antifibrinolyics (ie, epsilon aminocaproic acid [Amicar, Wyeth-Ayerst, Philadelphia, PA] and tranexamic acid), and desmopressin acetate (DDAVP, Rhone-Poulenc Rorer, Collegeville, PA). It focuses on their mechanisms of action, particularly their effect on microvascular tone and endothelial function, coagulation factors, platelet function, and the fibrinolytic pathway. It discusses their use in the presence of known thrombin production or fibrinogen conversion and whether certain vascular beds are more prone to drug-related thrombosis.

Fibrinolytic activity after subarachnoid haemorrhage and the effect of tranexamic acid

Seventy-four patients with recent subarachnoid haemorrhage were randomly allocated to placebo or tranexamic acid treatment. Fibrinolytic activity in the blood and cerebrospinal fluid was assessed before treatment, one week later and two weeks later. The natural history of fibrinolysis following subarachnoid haemorrhage was obtained from analysis of the placebo group. Following subarachnoid haemorrhage, fibrin degradation products and plasminogen activity in the cerebrospinal fluid were elevated. Subsequently, fibrin degradation products in the cerebrospinal fluid fell progressively over the following 2 weeks. Changes in cerebrospinal fluid plasminogen activity correlated with those of blood plasminogen activity. Complications such as rebleeding, hydrocephalus or cerebral thrombosis could not be predicted from analysis of fibrinolytic activity. Tranexamic acid treatment resulted in a reduction in cerebrospinal fluid and blood plasminogen activity. The relevance of fibrinolysis in cerebrospinal fluid and blood to the management of subarachnoid haemorrhage is discussed.

Rebleeding, ischaemia and hydrocephalus following anti-fibrinolytic treatment for ruptured cerebral aneurysms: a retrospective clinical study

350 patients with subarachnoid haemorrhage from aneurysmal rupture--admitted in the years 1966-1983--were selected for a retrospective controlled study on the efficacy of antifibrinolytic therapy (AFT). Patients treated with antifibrinolytics were divided into two groups, according to the day of hospital admission and onset of therapy, respectively between 0 and 3 days (SG 1) and between 4 and 7 days from SAH (SG 2); treated patients (260 cases) received i.v. tranexamic acid (6 gr/day) for at least two weeks. Patients admitted before 1974, not receiving antifibrinolytics (90 cases), were selected as controls and divided into two groups (CG 1 and CG 2), according to the day of admission. In the first study group (admission 0-3 days) the rebleeding rate within 2 weeks was 9% versus 23% in controls (p less than 0.01). The incidence of rebleeding within 3 and 4 weeks was also significantly lower (p less than 0.05) than in controls. No significant difference was observed in the rebleeding rate in treated and untreated patients with late admission (4-7 days). Mortality from rebleeding was 16% in the first study group versus 17% in controls; in the second study group the figure was 6% versus 8% in controls. Seventy-five cases of ischaemic disorders (29%) were registered in treated patients versus 13 cases in controls (14%; p less than 0.01). Thirty-seven patients receiving AFT (14%) developed significant ventricular dilatation requiring shunt insertion, versus one patient in the control groups (1%; p less than 0.001). Final outcome was similar in the 4 groups. In conclusion--according to our data--AFT modifies the behaviour of rebleeding and the patients' course, although it does not modify the outcome after SAH. Clinical use of antifibrinolytic therapy appears still justified in those patients who cannot be operated on in the acute stage after SAH, provided that an associated anti-ischaemic therapy is undertaken.

Significance of "ultra-early" rebleeding in subarachnoid hemorrhage

Knowledge of the local incidence of aneurysm rupture permits the conclusion that almost every patient in the population of 933,800 persons served by the authors' institution who was stricken by this catastrophe and survived long enough to be transported was treated at this center (121 patients during 34 months). Of these, 9.1% were admitted late (greater than 72 hours after subarachnoid hemorrhage (SAH]; of the remaining cases, 94.5% were seen within 24 hours and 50% within 6 hours post-SAH. Of the 121 patients, 10% were neurologically devastated on arrival, a late operation was planned for 19%, and the earliest possible surgery and nimodipine administration was selected for 71%. In this latter group, 50% of the operations were begun within 24 hours and 76% within 48 hours post-SAH. Sixty percent of all mortality and morbidity could be linked to the initial aneurysm bleed. The remaining 40% could be ascribed to potentially avoidable causes of unfavorable outcome. No less than 9.6% of all patients admitted within 24 hours after SAH suffered from "ultra-early" rebleeding during transportation or preparation for operation. The mortality rate from such rebleeding was 7.4%, compared with the 9.1% combined mortality rate from complications and late ischemia.

Antifibrinolytic treatment in subarachnoid hemorrhage

We enrolled 479 patients with subarachnoid hemorrhage in a multicenter, randomized, double-blind, placebo-controlled trial to determine whether treatment with the antifibrinolytic agent tranexamic acid improves outcome by preventing rebleeding. At three months there was no statistical difference between the outcomes in the tranexamic acid group and the control group. Of the 173 patients who died, 84 had received tranexamic acid and 89 placebo (95 per cent confidence interval for the difference in mortality rate, -6 to 11 per cent). Similarly, when analysis was restricted to patients with an angiographically demonstrated aneurysm, there was no significant difference between the groups. This absence of effect was not due to a lack of antifibrinolytic action, since the rate of rebleeding was reduced from 24 per cent in the control group to 9 per cent in the tranexamic acid-treated group (chi-square = 18.07, P less than 0.001), but resulted from a concurrent increase in the incidence of ischemic complications (15 per cent in the control group and 24 per cent in the tranexamic acid group; chi-square = 8.07, P less than 0.01). We conclude that until some method can be found to minimize ischemic complications, tranexamic acid is of no benefit in patients with subarachnoid hemorrhage.

Results of microsurgical management of ruptured intracranial aneurysms

The authors report the results of microsurgical management of 209 cases of ruptured intracranial aneurysms. The outcome of the surgery is discussed from the point of view of operative timing, preoperative grade, age and the effect of vasospasm. The operative results at the time of discharge were as follows: 137 excellent cases, 18 good, 31 fair, 8 poor and 15 deaths. The overall mortality rate was 7% and those patients designated as excellent and good who returned to work fully accounted for 74%. The result was achieved even though 65% of the patients were operated on within 2 weeks after the onset, and 44% of the patients were categorized as grade III, IV and V in Hunt's classification. In the morbidity and mortality, over half of the patients categorized as fair, poor and death were complicated by vasospasm, and the result was attributed mainly to the vasospasm. Therefore, we strongly believe that radical surgery is recommended to prevent rebleeding in the waiting period, there should be a greater understanding of "vasospasm" in order to improve overall morbidity and mortality.