Tranexamic acid for patients with aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis of 2991 patients

OBJECTIVE

We aimed to synthesize evidence from published clinical trials on the efficacy and safety of tranexamic acid (TXA) administration in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

We followed the standard methods of the Cochrane Handbook of Systematic Reviews for interventions and the PRISMA statement guidelines 2020 when conducting and reporting this study. A computer literature search of PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials was conducted from inception until 1 January 2022. We selected observational studies and clinical trials comparing TXA versus no TXA in aSAH patients. Data of all outcomes were pooled as the risk ratio (RR) with the corresponding 95% confidence intervals in the meta-analysis models.

RESULTS

Thirteen studies with a total of 2991 patients were included in the analysis. TXA could significantly cut the risk of rebleeding (RR 0.56, 95% CI 0.44 to 0.72) and mortality from rebleeding (RR 0.60, 95% CI 0.39 to 0.92, p = 0.02). However, TXA did not significantly improve the overall mortality, neurological outcome, delayed cerebral ischemia, or hydrocephalus (all p > 0.05). In terms of safety, no significant adverse events were reported. No statistical heterogeneity or publication bias was found in all outcomes.

CONCLUSION

In patients with aSAH, TXA significantly reduces the incidence of rebleeding and mortality from rebleeding. However, current evidence does not support any benefits in overall mortality, neurological outcome, delayed cerebral ischemia, or hydrocephalus.

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 In an effort to identify further published, unpublished, and ongoing studies, we searched reference lists and trial registers, performed forward tracking of relevant references, and contacted drug companies (the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.

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.