Use of epsilon aminocaproic acid (EACA) in the preoperative management of ruptured intracranial aneurysms

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 In an effort to identify further published, unpublished, and ongoing studies we searched reference lists and trial registers, performed forward tracking of relevant references and contacted drug companies.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

Controlled hypotension and blood loss during frontoorbital advancement

OBJECT

Controlled hypotension is routinely used during open repair of craniosynostosis to decrease blood loss, although this benefit is unproven. In this study the authors analyzed the longitudinal relationships between intraoperative mean arterial pressure (MAP) and calculated blood loss (CBL) during frontoorbital advancement (FOA) for craniosynostosis.

METHODS

The authors reviewed the records of infants with craniosynostosis who had undergone primary FOA between 1997 and 2009. Anesthesia records provided preoperative and serial intraoperative MAP. Interval measures of CBL had been determined during the course of the operation. The longitudinal relationships between MAP(mean), MAP(change), and CBL(change) were assessed over the same time interval and compared between adjacent time intervals to determine the directionality of associations.

RESULTS

Ninety infants (44 males and 46 females) underwent FOA at a mean age and weight of 10.7 ± 12.9 months and 9.0 ± 7.0 kg, respectively. The average intraoperative MAP was 56.1 ± 4.8 mm Hg, 22.6 ± 12.1% lower than preoperative baseline. A negative correlation was found between CBL(change) and MAP(mean) over the same interval (r = -0.31, p < 0.05), and an inverse relationship was noted between CBL(change) of the previous interval and MAP(change) of the next interval (r = -0.07, p < 0.05). Finally, there was no significant association between MAP(change) of the previous interval and CBL(change) of the next interval.

CONCLUSIONS

Calculated blood loss demonstrated a negative correlation with MAP during FOA. Directionality testing indicated that MAP did not affect intraoperative blood loss; instead, blood loss drove changes in MAP. Overall, these findings challenge the benefit of controlled hypotension during open craniofacial repair.

Antifibrinolytic therapy in the management of aneurismal subarachnoid hemorrhage revisited. A meta-analysis

BACKGROUND

To reassess the use of antifibrinolytics (AF) in the management of aneurysmal subarachnoid hemorrhage (SAH) in the setting of present-day treatment strategies.

METHOD

The authors conducted a systematic review of the literature and a meta-analysis. They reviewed the PubMed database and conducted a manual review of article bibliographies.

RESULTS

Using a pre-specified search strategy, 17 relevant studies involving a total of 2,872 patients with SAH at baseline, from which data of 1,380 patients having received AF, were included in a meta-analysis. Pooled odds ratios of the impact of AF on functional outcomes, rebleeding, and cerebral infarction were calculated. Short-term use of AF (72 h or less) associated with medical prevention of ischemic deficit seems to yield better results on functional outcome than long-term use of AF, especially if not associated with a medical prevention of ischemic deficit. The risk of cerebral infarction is not increased by the short-term use of AF and the risk of rebleeding is decreased independently of the length of AF use.

CONCLUSIONS

The use of AF should be reconsidered in the setting of modern-era treatment strategies, as the short-term use associated with medical prevention of ischemic deficit decreases the rate of rebleeding and does not increase the risk of cerebral infarction, thus potentially yielding better protection against poor functional outcome.

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.

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.

Cerebral sinus thrombosis as a potential hazard of antifibrinolytic treatment in menorrhagia

We describe a 42-year-old woman who developed superior sagittal and left transverse sinus thrombosis associated with prolonged epsilon-aminocaproic acid therapy for menorrhagia. This antifibrinolytic agent has been used in women with menorrhagia to promote clotting and reduce blood loss. Although increased risk of thromboembolic disease has been reported during treatment with epsilon-aminocaproic acid, cerebral sinus thrombosis has not been previously described. Careful use of epsilon-aminocaproic acid therapy is recommended.

Benefits and risks of antifibrinolytic therapy in the management of ruptured intracranial aneurysms. A double-blind placebo-controlled study

One hundred patients with a verified subarachnoid haemorrhage were studied in a double blind, placebo-controlled trial at a single centre to determine the value and relative risks of tranexamic acid (TXA) in the management of ruptured intracranial aneurysms. The incidence of recurrent haemorrhage between active and placebo groups was identical (12%) and the mortality from recurrent haemorrhage was 7% and 5%, respectively. The overall incidence of cerebral infarction before surgery, at discharge and at 6 months follow-up was greater in the TXA group (27%) than in the control group (11%). Post-operative cerebral ischaemia was significantly more frequent in the active, 18 of 29 as compared to 6 of 32 patients, in the placebo group. In a fifth of the patients in whom cerebral blood flow was estimated there was a significant reduction of cerebral blood flow (CBF) on the side of the ruptured aneurysm in the TXA treated group. It is suggested that this may be the cause of the increased incidence of cerebral ischaemia in this group. There was no significant difference in the incidence of cerebral vasospasm, hydrocephalus, visual disturbances and gastrointestinal disturbances. More fatalities were encountered from ischaemia and recurrent haemorrhage in the TXA group but these differences did not reach statistical significance at the 5% level. Given that disability was due to either vasospasm or recurrent haemorrhage than a patient under TXA treatment was significantly more likely to have disability due to vasospasm (p less than 0.04); the reverse was true for the placebo patient (p less than 0.05).

Rerupture of intracranial aneurysms during angiography

We analyzed 70 patients (64 from the literature and 6 of our own cases) who had suffered from rerupture of their aneurysms during angiography. When these cases are compared with those who had suffered rupture of their aneurysms only once and a rerupture, which did not coincide with angiography, they were clinically distinguished by a higher Hunt-Hess grade, a higher rate of IC aneurysms, less operability, far miserable outcome and concentration of aneurysmal rerupture within three hours after the initial subarachnoid haemorrhage. It is suggested waiting at least 3 hours after SAH before performing angiography and to use digital subtraction angiography in order to prevent aneurysmal rerupture during angiography.

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.

Antifibrinolytic agents in subarachnoid haemorrhage

For many years clinicians have used antifibrinolytic agents to try to reduce rebleeding after subarachnoid haemorrhage. Early studies of their effectiveness produced conflicting results. This paper re-evaluates the available trials and considers benefits in the light of potential complications. Present evidence conclusively demonstrates that epsilon-aminocaproic acid and tranexamic acid administered in standard dosage, reduce the risk of rebleeding but, as a result of an increased incidence of ischaemic complications, do not benefit patients' outcome.

Observations on the perioperative management of aneurysmal subarachnoid hemorrhage

Thirty-two patients with aneurysmal subarachnoid hemorrhage (SAH) were managed according to a protocol based on pain control and hemodynamic manipulation, monitored by an arterial line and Swan-Ganz catheter. Hemodynamic parameters were adjusted to four clinical situations. 1) For the unoperated patient with no neurological deficit, the regimen aims to maintain pulmonary wedge pressure (PWP) at 10 to 12 mm Hg, and the cardiac index (CI) and blood pressure (BP) at normal levels. 2) For the unoperated patient presenting with or developing neurological deficit, the PWP is increased until the deficit is reversed or the CI falls; the CI is high, and the BP normal. 3) For the postoperative patient with no neurological deficit, the PWP is maintained at 12 to 14 mm Hg, the CI is a high normal, and the BP is normal. 4) For the postoperative patient developing neurological deficit but showing no surgical complication on the computerized tomography scan, the PWP is increased until the deficit is reversed or the CI falls; the CI is high and the BP is increased with vasopressors if necessary. Fourteen patients developed neurological deficits either preoperatively, postoperatively, or both. Neurological deficits were repeatedly reversed by increasing the PWP, as measured hourly. In several patients an optimal wedge pressure was determined, below which deficits would reappear. In one patient whose neurological deficit was reversed on several occasions by increasing the PWP, the optimal PWP rose after each episode until it reached 22 mm Hg. Detailed event-related analysis of these patients' course illustrates these phenomena well. The optimal PWP varied from patient to patient, but ranged most frequently from 14 to 16 mm Hg. Meticulous monitoring of the patients' neurological status coupled with prompt correction of low PWP (assuming an adequate CI) has proven to be an effective way to prevent and reverse neurological deficits following aneurysmal SAH.

Effects of human exposure to atmospheric epsilon-caprolactam

There is little published information on the human toxicology of epsilon-caprolactam, the monomer precursor of nylon 6. This paper reports an investigation of a group of eight workers who had been chronically exposed to atmospheric caprolactam levels of around 70 times the current ACGIH threshold limit value (TLV). No evidence of systemic toxicity was found, although all workers showed a greater or lesser degree of skin change in the form of peeling and/or fissuring.

An experimental study of the influence of antifibrinolytic therapy on post-subarachnoid-hemorrhagic cerebral vasospasm and hydrocephalus

The incidence and severity of cerebral vasospasm and hydrocephalus following induced subarachnoid hemorrhage in an experimental group of animals that subsequently received epsilon-aminocaproic acid was compared to that seen in a control group that received no antifibrinolytic therapy. No augmentation of either vasospasm or hydrocephalus could be attributed to the epsilon-aminocaproic acid in the treated as compared to the control group.

Disseminated intravascular coagulation as a complication of ruptured intracranial aneurysms. Report of two cases

Two patients with recently ruptured intracranial aneurysms underwent surgical repair of these vascular lesions. Postoperatively, they showed clinical and laboratory evidence of disseminated intravascular coagulation (DIC). In both patients severe cerebral ischemic complications occurred. In one case the ischemic complications and the hematological changes were successfully reversed. This syndrome is a potential complication of aneurysmal subarachnoid hemorrhage (SAH), which requires prompt diagnosis and appropriate management. The relationship between hematological changes suggesting DIC and the ischemic complications of SAH should be extensively investigated.

Pharmacologic management of subarachnoid hemorrhage

Subarachnoid hemorrhage, following rupture of an intracranial aneurysm, affects about 25 000 people in the U.S. each year. Less than half the patients who survive until hospital admission have an overall favorable outcome. This high morbidity and mortality rate is a result of serious complications following the initial subarachnoid hemorrhage, the most significant of these being rebleeding and cerebral ischemia secondary to vasospasm. While surgical clipping of the aneurysm is the most definitive therapy, this procedure may be postponed for a week or two after the initial hemorrhage, depending on the patient's clinical condition. Pharmacological therapy is a critical part of the preoperative care of these patients and of the postoperative management of complications. This article discusses the syndromes of rebleeding and vasospasm and reviews the current pharmacologic therapy for each.

Double-blind trial of aspirin in patient receiving tranexamic acid for subarachnoid hemorrhage

Antifibrinolytic agents have been claimed to reduce the rebleed rate in patients with subarachnoid haemorrhage from intracranial aneurysms. However, these agents may in themselves increase the incidence of delayed cerebral ischaemia in these patients. We have used aspirin in an attempt to reduce the incidence of this complication. In a prospective, double-blind trial of aspirin against placebo, 53 patients with subarachnoid haemorrhage were all treated with the antifibrinolytic agent tranexamic acid. Twenty-seven patients received aspirin and 26 patients received placebo. The morbidity and mortality was similar in each group. A further breakdown into patients who had their aneurysms clipped at craniotomy (21 patients) similarly failed to show a more favourable outcome in either group. It is concluded that aspirin does not affect the outcome in patients with subarachnoid haemorrhage treated with tranexamic acid.

Antifibrinolytic treatment in subarachnoid haemorrhage: present state

Two randomised controlled clinical trials in patients with recently ruptured intracranial aneurysms were undertaken using tranexamic acid (AMCA) to prevent early recurrent bleeding. In our accumulated series of 105 patients 53 were given AMCA and 52 were controls. 13% of the AMCA-treated patients and 31% of the controls rebled. In patients treated with AMCA the recurrent bleeding took place later than the rebleeding in the control patients. Vasospasm and delayed cerebral ischaemic deficits were seen more frequently in patients treated with AMCA. Total mortality from rebleeding and cerebral ischaemia was 25% in AMCA-treated patients and 19% in the controls during the six weeks' observation time. Coagulation factors remained unaffected by the drug. Local fibrinolysis in the cerebrospinal fluid decreased after one week in patients treated with AMCA. After two weeks the fibrinolytic activity was similar in AMCA-treated patients and in the controls. After experimental subarachnoid haemorrhage in 90 rabbits, AMCA was found to suppress plasminogen activator activity, mainly in the leptomeninges. This occurred however only during the first few postbleeding days. Antifibrinolytic agents only appear to reduce the risk of recurrent bleeding during the first ten day period after the primary aneurysm rupture. However they also seem to produce delayed cerebral ischaemia in patients with subarachnoid haemorrhage. Synthetic antifibrinolytics evidently shift the incidence of rebleeding curve to the right but these drugs are probably of diminished value in the subsequent weeks of risk.

Medical management of patients following a ruptured cerebral aneurysm, with epsilon-aminocaproic acid, kanamycin, and reserpine

Patients suffering from a subarachnoid hemorrhage who were admitted to the Neurosurgical Unit of the Royal Perth Hospital during the period 1971 to 1979 were assessed with regard to the effectiveness of preoperative treatment with epsilon-aminocaproic acid, kanamycin, and reserpine. Forty-two patients who were treated with epsilon-aminocaproic acid had a rebleed rate of 2.3% compared to 1 9.7% rebleed rate in appropriately selected controls. Patients treated with kanamycin and reserpine had a preoperative cerebral vasospasm rate of 32% compared to a 26% rate in controls; however, kanamycin and reserpine were found useful for decreasing the postoperative complications of cerebral vasospasm.

Considerations in early surgery on good-risk patients with ruptured intracranial aneurysms

A retrospective analysis of 100 consecutive patients with proven ruptured intracranial aneurysms, classified as Botterell Grades I to III on admission, was carried out to evaluate the efficacy of early operation. Surgical and management mortality/morbidity rates were lower for cases in which a single hemorrhage was operated on within 48 hours than when surgery was delayed for 7 days or more. Surgical and management mortality/morbidity rates were worse in good-risk patients treated surgically between the 3rd and 7th days following a hemorrhage, reflecting the increased incidence of postoperative vasospasm and raised intracranial pressure encountered at surgery during this interval.

Comparative clinical trial of epsilon amino-caproic acid and tranexamic acid in the prevention of early recurrence of subarachnoid haemorrhage

A comparative controlled clinical trial of epsilon aminocaproic acid (EACA), 36 g/day and tranexamic acid (TEA), 6 g/day, was undertaken to assess their effectiveness in reducing early recurrence of subarachnoid haemorrhage (SAH). Of 90 patients treated with EACA recurrent haemorrhage was seen in 8% of these patients and 7% of the patients developed delayed ischaemic deficit. The total pre-operative mortality in EACA-group was 11%. Of 61 patients treated with TEA, 10% had recurrent haemorrhage and delayed ischaemic deficit occurred in 5% of the patients. The total pre-operative mortality in TEA-group was 11%. No difference was found between the effectiveness and side-effects of these drugs.

The changing angiographic appearance of an arteriovenous malformation after subarachnoid hemorrhage

The changing angiographic appearance of a cerebral arteriovenous malformation (AVM) illustrated hemodynamic changes that can occur following subarachnoid hemorrhage and antifibrinolytic therapy. Decreased size of this lesion suggested thrombosis of the AVM. This appearance actually represented a transient, vasospastic phenomenon which reversed with time. Although the AVM underwent significant changes acutely, little changed in the long term.

Fibrinolytic activity of cerebral tissue after experimental subarachnoid haemorrhage: inhibitory effect of tranexamic acid (AMCA)

The influence of tranexamic acid (AMCA) on the fibrinolytic activity induced by plasminogen activators (PA) of the cerebral leptomeninges, arteries and choroid plexus after artificial subarachnoid haemorrhage (SAH) was studied in 90 rabbits. SAH was induced by injection of 1-2 ml autologous blood into the suboccipital cistern. Half of the rabbits were given AMCA, 200 mg per kg body weight, in daily single i.v. injections. The rabbits were sacrificed after 3-5, 8-10 and 14-15 days respectively. Part of the leptomeninges, basilar artery and choroid plexus were removed for assaying PA by the histochemical fibrin slide and fibrin plate methods, using thiocyanate for extraction of plasminogen activator from the tissues. Quantitative assays for the fibrin plate method showed high PA in the arterial and meningeal tissues from the untreated animals 3-5 days after SAH. The PA had decreased to normal levels 8-10 days after SAH but increased again 14-15 days after SAH. A lower PA in the choroid plexus followed the same pattern. The concentration of the primary plasmin inhibitor in plasma had decreased to half of the normal value 8 days after SAH when compared to the concentration in pooled plasma from normal rabbits. In AMCA treated animals the meningeal PA, assayed by both methods, was decreased 3-5 days after SAH while no or an insignificant decrease in PA was seen 8-10 and 14-15 days after SAH. The PA of the arterial vessel wall and choroid plexus in the AMCA treated animals, assayed by the histochemical method, was moderately decreased 3-5 days after SAH, while no significant differences between untreated and AMCA treated animals were seen after 8-10 or 14-15 days when the tissues were assayed by either method. These findings indicate that AMCA suppresses PA primarily in the leptomeninges during the first few days after SAH and presumably before the meningeal fibrosis has developed.

Pharmacokinetics of epsilon-aminocaproic acid during peritoneal dialysis

Two patients requiring peritoneal dialysis were treated with epsilon-aminocaproic acid (EACA), an antifibrinolytic agent. Samples of serum and dialysate were assayed for EACA concentrations. Total body clearance, dialysis clearance, EACA half-life, and volume of distribution of EACA were calculated. Total body clearance of EACA was 26 ml/min, which is 25% of the drug clearance in patients with normal renal function. Our results suggest that patients undergoing peritoneal dialysis should receive 25% of the usual recommended dose of EACA. Dialysis clearance accounted for only 58% of total body clearance, suggesting an alternative route of elimination of EACA.

Subarachnoid hemorrhage in middle-Finland: incidence, early prognosis and indications for neurosurgical treatment

The incidence of subarachnoid hemorrhage (SAH) in Middle-Finland 1976-78 was 19.4/100,000/year. The incidence increased consistently with age. The early prognosis was similar to that in earlier studies, with 25% dying on the first day, and 49% during the first 3 months after the initial bleeding. The fatality rate decreased sharply after the bleeding: of all deaths during the first 3 months, the weekly fatality rate was 65% during the 1st week, 12% during the 2nd, and 4% during the 3rd. Thereafter the weekly fatalities up to 3 months averaged 1.6%. Only 20% of the patients of the entire series were assessed as being eligible for neurosurgical treatment. Intercurrent fatal rebleeds further reduced this number. The chances of increasing the number of SAH patients suitable for neurosurgery are discussed. The timing of surgery should be earlier than in the present study (median 15 days after the bleeding) in order to avoid frequently fatal recurrences. Vertebral angiograms should be obtained from patients with no aneurysms found by bilateral carotid angiography. The upper age limit of 60 years should be abolished. By these means the proportion of SAH patients potentially eligible for neurosurgery could be increased to about 40%.

Coagulation and fibrinolysis in blood and cerebrospinal fluid after aneurysmal subarachnoid haemorrhage: effect of tranexamic acid (AMCA)

Serial assays of blood coagulation factors as well as of fibrin/fibrinogen degradation products (FDP) and plasminogen activatory activity (PA) on fibrin plates in blood and cerebrospinal fluid (CSF) were performed in 41 consecutive patients with recently ruptured cerebral aneurysms, 21 of whom were randomly treated with tranexamic acid (AMCA). Coagulation factors were unaffected by the drug and plasminogen and FDP decreased in blood after two weeks' treatment. After one week, PA in CSF was increased in control patients and unchanged in AMCA-treated patients, whereas CSF-FDP had decreased among AMCA-treated patients. After two weeks PA as well as FDP in CSF showed the same values in both groups. An increase in CSF-FDP occurred after rebleeding and in patients with cerebral ischaemic symptoms. The results indicate that AMCA inhibits local fibrinolysis in CSF in patients with aneurysm rupture.

Anti-fibrinolytic treatment in the pre-operative management of subarachnoid haemorrhage caused by ruptured intracranial aneurysm

One hundred consecutive patients treated with epsilon aminocaproic acid 24 grams daily prior to surgery for ruptured intracranial aneurysms have been compared with the previous 100 patients managed similarly but without anti-fibrinolytic drugs. No other alterations in management were made and the two series are closely comparable in all other respects. Fewer episodes of recurrent haemorrhage and deaths from this cause occurred in the treated patients, but more cases of cerebral ischaemia occurred. Neither difference is statistically significant and overall more deaths occurred in the patients treated with antifibrinolytic drugs. The value of this method of treatment in the management of aneurysmal subarachnoid haemorrhage is questioned.

A method for monitoring antifibrinolytic therapy in patients with ruptured intracranial aneurysms

A rapid fluorometric assay technique has been utilized to assess the degree of fibrinolytic inhibition in 20 patients with ruptured intracranial aneurysms treated with epsilon-aminocaproic acid (EACA). This method quantitates the available plasminogen activity (APA) of plasma, and has proven to be a reliable means of monitoring antifibrinolytic therapy. Determination of the plasma APA also permits correlation of the level of fibrinolytic activity with putative complications of EACA therapy. Normal control plasma APA was 3.1 +/- 0.7 CTA units/ml, but in patients with subarachnoid hemorrhage (SAH), pretreatment fibrinolytic activity was supranormal at 3.78 +/- 0.88 CTA units/ml. During continuous intravenous administration of EACA (1.5 gm/hr) in patients with SAH, the plasma fibrinolytic activity was decreased to 0.9 +/- 0.31 CTA units/ml. A case described which examplifies the use of this assay. In addition, an approach to monitoring antifibrinolytic therapy using the plasma APA is proposed.

Thrombosis: the relationship of hemostatic mechanisms to drug therapy

The mechanism of action and present clinical role of drugs affecting hemostasis in the therapy of spontaneous, postoperative, and posttraumatic arterial thrombosis, arterial embolism, venous thrombosis, pulmonary embolism, and intracranial aneurysm have been reviewed. Both the management of neurosurgical problems and the development of antithrombotic regimens are improving. In regard to the use of drug therapy, discussed herein, each surgeon will reach his own decision based on his findings in the individual patient, and may wisely elect in specific situations not to employ drug therapy. The comments offered in ths analysis are to be construed as suggestions not mandates, as they will undoubtedly undergo modification with time. In closing, it is appropriate to recall a famous Chinese curse: "May you live," it reads, "in a time of transition."

Epsilon-aminocaproic acid and recurrent subarachnoid hemorrhage: a clinical trial

A clinical trial of epsilon-aminocaproic acid (EACA) in preventing recurrent hemorrhage from intracranial arterial aneurysms is reported. Previous reports were reviewed, and their results concerning antifibrinolytic agents were inconclusive in establishing their efficacy. One hundred patients with documented ruptured intracranial aneurysms were admitted to this study within 48 hours of the initial hemorrhage: 45 patients received 36 gm of EACA/day, with 11 documented rebleeds and one suspected rebleed. No benefit was seen from the use of EACA.

Preoperative treatment of ruptured intracranial aneurysms with tranexamic acid and monitoring of fibrinolytic activity

The fibrinolytic activity in cerebrospinal fluid has been monitored by determination of levels of fibrin split products (FSP) in 23 patients with ruptured intracranial aneurysms. In 20 of these 23, FSP was found in the cerebrospinal fluid (CSF), with levels ranging from 10 to 80 micrograms/ml. Eleven of the 23 patients were treated with 2 gm tranexamic acid daily. In these patients FSP was found in only two cases during the 2nd week, while in 12 untreated patients it was found in 10 cases. These results suggest that there exists a localized fibrinolytic activity, and monitoring the FSP levels in the CSF may be a simple and accurate method for controlling the efficiency of antifibrinolytic therapy. Thus, treatment could be begun with a lower dose, which could be increased later as deemed necessary from the results of careful monitoring.

Modern treatment of intracranial aneurysms

The initial physical and neurologic examinations usually allow a presumptive diagnosis of intracranial aneurysm, but confirmation may require computed tomography (CT) and selective angiography. Medical management of the patient necessitates close observation, supportive care, and use of drugs to reduce intracranial pressure and to prevent dissolution of clot at the aneurysmal fundus to prevent rebleeding. The age of the patient may be a deciding factor in selection of surgical candidates. The surgical procedure of choice is direct obliteration of the aneurysm by clipping or ligation, unless such a procedure would compromise the patency of major intracranial vessels or not be possible because of the shape of the aneurysm. With aggressive medical management and modern surgical techniques, many more of these patients may be saved and returned to productive life.

Monitoring fibrinolytic activity in the cerebrospinal fluid after aneurysmal subarachnoid haemorrhage: a guide to the risk of rebleeding?

Serial assay of fibrin degradation products (FDPs) was used to monitor fibrinolytic activity in blood and cerebrospinal fluid (CSF) after subarachnoid haemorrhage (SAH) in 64 patients, 43 of whom had aneurysms. CSF levels fell rapidly from high initial values over a few days, thereafter more slowly to reach normal levels after one to six weeks. Probably only the later slow decline is a measure of fibrinolysis, which is obscured in the first few days by the cross antigenicity with FDP's of fibrinogen released by the bleed. After this phase of fibrinogen clearance, early attainment of normal FDP levels appears to be associated with a lower risk of rebleeding in cases of aneurysm. This phenomenon could be useful in deciding whether marginal cases should be treated surgically or conservatively.

The treatment of postperfusion bleeding using epsilon-aminocaproic acid, cryoprecipitate, fresh-frozen plasma, and protamine sulfate

The evaluation of excessive hemorrhage was carried out in 774 patients after cardiopulmonary bypass. Excessive hemorrhage was defined in any adult patient as chest tube drainage of more than 600 ml within the first eight hours after operation. Using the prothrombin time, partial thromboplastin time, fibrinogen level, and tri-F titer tests, it was possible to differentiate medical from surgical bleeding. Hyperfibrinolytic bleeding was the most frequently identifiable coagulation disorder and occurred in 159 patients (20%). All these patients were successfully treated with Amicar (epsilon-aminocaproic acid) alone, or with Amicar supplemented with cryoprecipitate or fresh-frozen plasma. Three patients (0.4%) were noted to have residual heparin and required additional protamine sulfate. Five patients (0.6%) had normal coagulation studies and required immediate reexploration. The overall blood consumption per patient was 2.1 units of packed cells. Whole blood and platelets were not used.

Tranexamic acid in subarachnoid hemorrhage. A double-blind study

The effects of intravenous tranexamic acid were compared with placebo in 64 patients with subarachnoid hemorrhage. A double-blind procedure was used. One gram of tranexamic acid was given intravenously every 4 hours up to the time of operation on an intracranial arterial aneurysm or for up to 21 days after the first bleeding if operative treatment was not feasible. There were no differences in re-bleeds, morbidity or mortality between the tranexamic and placebo-treated groups. No thromboembolic complications were noted in either group. Our results do not support the use of tranexamic acid in subarachnoid hemorrhage in daily doses of 6 g.

The physiopathology of respiration in neurosurgical patients

✓ Regulation of respiration is summarized as to peripheral and central chemoreceptors, controllers of voluntary and automatic respiration, and stimulators (CO2, O2, and pH). The information that may be obtained from blood-gas analysis is reviewed and basic problems in acid-base imbalance described. Commonly employed respiratory patterns are discussed.

Preoperative pulmonary assessment necessary in elective intracranial situations, spinal cord injuries, and pediatric neurosurgery is outlined. Some of the special problems of the patient with multiple trauma, including injury to the central nervous system are reviewed. Central and peripheral factors that cause respiratory difficulty in head-injured patients are tabulated, and an outline is given of diagnosis and therapy. There are many possible causes of intraoperative hypoxia and hypercarbia, and these complications with their prevention or treatment are examined. Criteria for extubation are established. Finally, postoperative pulmonary care in elective, emergency, and cord injury situations is discussed. The key to successful perioperative pulmonary care of the neurosurgical patient requires close cooperation between the neurosurgeon and anesthesiologist.

Prevention of early recurrence of spontaneous subarachnoid haemorrhage by epsilon-aminocaproic acid

A controlled clinical trial of epsilon-aminocaproic acid (E.A.C.A.), 36 g/day, was undertaken to assess its effectiveness in reducing immediate recurrence in patients with spontaneous subarachnoid haemorrhage (S.A.H.) proved by lumbar puncture. Of 83 patients treated with E.A.C.A., 3 (4%) had recurrent haemorrhage, and 1 (33%) of these died. Of 82 control patients who were not given any antifibrinolytic drug, 22 (26%) had recurrent haemorrhage, and 10 (45%) of these patients died. E.A.C.A. produced a striking reduction in the early recurrence of S.A.H. No serious side-effect resulted.

Scope of surgery for intracranial aneurysm in the elderly: a preliminary report

Thirty-two elderly patients were reviewed six months to six years after intracranial surgery for subarachnoid haemorrhage. Out of 24 patients whose surgical outcome had been satisfactory, one had died from an unrelated illness and the remainder were well and leading normal lives. Eight patients had a poor outcome, which in some cases was due to factors other than age. In only three could a poor outcome be attributed to early surgery and advanced age. The results confirm that in at least three-quarters of patients aged 60-65 the risk of further haemorrhage can be removed by surgery without causing a major neurological deficit.

Coagulation and fibrinolytic activity of cerebrospinal fluid

Fibrin/fibrinogen degradation products (fragments D and E) were detected in cerebrospinal fluid in 23.4% of 252 patients admitted to a neurological/neurosurgical unit. Other coagulation proteins of low molecular weight (plasminogen and factor IX) were also present but larger proteins (fibrinogen and factor V) were not. These findings are consistent with protein leakage across a blood-CSF barrier damaged by inflammatory, vascular, or neoplastic disease. Fibrin/fibrinogen degradation products in cerebrospinal fluid after subarachnoid haemorrhage may not, therefore, be a reliable index of increased fibrinolytic activity in the subarachnoid space and may be misleading when selecting patients for fibrinolytic blockade.

Intraocular hemorrhages: a hemostatic therapeutic approach

Our knowledge of the local hemostatic factors capable of playing a role in certain intraocular hemorrhages is reviewed as a background to therapy with agents active in hemostasis. Common to hyphemas and subretinal hemorrhages are some conditions which are apt to disturb hemostasis and result in recurrent bleeding. They are: 1) Dilution of blood by aqueous humor or subretinal exudative fluid followed by the formation of hemostatic plugs which are prone to spontaneous lysis; 2) Contiguity of certain structures, such as the iris and the choroid, which are extremely rich in fibrinolytic activators favoring premature dissolution of the hemostatic plug and thereby recurrent bleeding; and 3) Presumptive high local concentration of fibrin degradation products (FDP), which have an anticoagulant action and would counteract hemostasis in the event of rebleeding. Based on these observations, the use of fibrinolytic inhibitors for the treatment of hyphema and subretinal hemorrhages seems warranted. Hemostatic mechanisms in intraocular hemorrhages and their treatment with various agents are discussed.