Patches of different types for carotid patch angioplasty

BACKGROUND

Some surgeons who use carotid patching favour using the saphenous vein, whilst others favour synthetic materials.

OBJECTIVES

The objective of this review was to assess the effect of different materials for carotid patch angioplasty.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995) and Index to scientific and technical proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular and Endovascular Surgery (1987 to 1995) and World Journal of Surgery (1978 to 1995).

SELECTION CRITERIA

Randomised trials comparing one type of carotid patch with another for carotid endarterectomy.

DATA COLLECTION AND ANALYSIS

One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed.

MAIN RESULTS

Three trials involving 326 operations were included. The trials compared saphenous vein patches with synthetic polytetrafluroethylene patches. Allocation was not adequately concealed in two trials, and only one followed-up patients until hospital discharge. Intention-to-treat analysis was only possible for the latter trial. In all trials a patient could be randomised twice and have each carotid artery randomised to different treatment groups. One trial was excluded from the analyses of death and any stroke because it was not possible to clarify how many patients, rather than arteries, were allocated to each treatment. There were too few events to determine whether there was any difference between the patch materials for perioperative stroke, death and arterial complications. During longterm follow-up for more than one year, no difference was shown between the two types of patch for the risk of stroke, death, or arterial restenosis. However, the number of events was small. Based on 236 patients in two trials, there were significantly fewer pseudoaneurysms associated with synthetic patches (odds ratio 0.15, 95% confidence interval 0.05 to 0.44).

REVIEWER'S CONCLUSIONS

There is not enough evidence to differentiate between venous and synthetic patches in carotid endarterectomy.

Anticoagulants for acute ischaemic stroke

BACKGROUND

Most ischaemic strokes are caused by blood clots blocking an artery in the brain. Clot prevention with anticoagulant therapy could have a significant impact on patient survival, disability and recurrence of stroke.

OBJECTIVES

The objective of this review was to assess the effect of anticoagulant therapy in the early treatment of patients with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (most recent search: March 1999) and consulted MedStrategy (1995). We also contacted drug companies.

SELECTION CRITERIA

Randomised trials comparing early anticoagulant therapy (started within two weeks of stroke onset) with control in patients with acute presumed or confirmed ischaemic stroke.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Twenty-one trials involving 23,427 patients were included. The quality of the trials varied considerably. The anticoagulants tested were standard unfractionated heparin, low-molecular-weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Based on eight trials (22,450 patients) there was no evidence that anticoagulant therapy reduced the odds of death from all causes (odds ratio 1.05, 95% confidence intervals 0.98-1.12). Similarly, based on five trials (21, 846 patients), there was no evidence that anticoagulants reduced the odds of being dead or dependent at the end of follow-up (odds ratio 0.99, 95% confidence intervals 0.94-1.05). Although anticoagulant therapy was associated with about 9 fewer recurrent ischaemic strokes per 1000 patients treated, it was also associated with a similar sized 9 per 1000 increase in symptomatic intracranial haemorrhages. Similarly, anticoagulants avoided about 4 pulmonary emboli per 1000, but this benefit was offset by an extra 9 major extracranial haemorrhages per 1000. Sensitivity analyses did not identify a particular type of anticoagulant regimen or patient characteristic associated with net benefit.

REVIEWER'S CONCLUSIONS

Immediate anticoagulant therapy in patients with acute ischaemic stroke is not associated with net short- or long-term benefit. The data from this review do not support the routine use of any type of anticoagulant in acute ischaemic stroke.

Local versus general anaesthesia for carotid endarterectomy

BACKGROUND

Carotid endarterectomy reduces the risk of stroke in people with recently symptomatic, severe carotid artery stenosis. However, there are significant perioperative risks which may be lessened by performing the operation under local rather than general anaesthetic.

OBJECTIVES

The objective of this review was to assess the effect of endarterectomy under local compared with general anaesthetic.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995), and Index to Scientific and Technical Proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular Surgery (1988 to 1995) and World Journal of Surgery (1978 to 1995). Reference lists of articles were searched.

SELECTION CRITERIA

Randomised trials and non-randomised studies comparing carotid endarterectomy under local versus general anaesthetic.

DATA COLLECTION AND ANALYSIS

One reviewer selected studies for inclusion and another independently checked the decisions. Two reviewers assessed trial quality and independently extracted the data.

MAIN RESULTS

Three randomised trials involving 143 patients, and 17 non-randomised studies involving about 5970 patients were included. The methodological quality of the randomised trials was questionable. Two of the non-randomised studies were prospective and 12 reported on a consecutive series of patients. In nine non-randomised studies the number of patients, as opposed to the number of arteries, was unclear. There were insufficient data to enable conclusions to be drawn from the randomised trials. In 15 non-randomised studies, no significant difference was shown between local and general anaesthetic in deaths within 30 days of operation (odds ratio 0.61, 95% confidence interval 0.32 to 1.16). Non-randomised studies showed that local anaesthetic was associated with a significant reduction in the odds of stroke (15 studies), stroke or death (14 studies), myocardial infarction (12 studies), and pulmonary complications (five studies), within 30 days of the operation. Patient and surgeon satisfaction were not reported in any study.

REVIEWER'S CONCLUSIONS

There is not enough evidence from randomised trials comparing carotid endarterectomy performed under local as opposed to general anaesthetic. Non-randomised studies suggest potential benefits with local anaesthetic. However these studies are likely to be significantly biased.

Patch angioplasty versus primary closure for carotid endarterectomy

BACKGROUND

Carotid patch angioplasty (with either a venous or a synthetic patch) may reduce the risk of carotid artery restenosis and subsequent ischaemic stroke.

OBJECTIVES

The objective of this review was to assess the effect of routine or selective carotid patch angioplasty compared to carotid endarterectomy with primary closure.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995) and Index to Scientific and Technical Proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular and Endovascular Surgery (1987 to 1995) and World Journal of Surgery (1978 to 1995).

SELECTION CRITERIA

Randomised trials comparing carotid patch angioplasty with primary closure in any patients undergoing carotid endarterectomy.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed eligibility, trial quality and extracted the data.

MAIN RESULTS

Six trials involving 794 patients and 882 operations were included. The quality of trials was generally poor. Follow-up varied from hospital discharge to five years. Carotid patch angioplasty showed a reduction in the risk of stroke of any type, ipsilateral stroke, and stroke or death, during the perioperative period and longterm follow-up. However, data were not available from all trials, the number of events was small and there was significant loss to follow-up. Patching appeared to reduce the risk of perioperative arterial occlusion (six trials, odds ratio 0.17, 95% confidence interval 0.06 to 0.46). Patching was also associated with decreased restenosis during longterm follow-up in five trials, (odds ratio 0.32, 95% confidence interval 0.19 to 0.53). However, these results are uncertain because of loss to follow-up and the small number of events. Very few arterial complications, including haemorrhage, infection, cranial nerve palsies and pseudo-aneurysm formation were recorded with either patch or primary closure.

REVIEWER'S CONCLUSIONS

Limited evidence suggests that carotid patch angioplasty may lower the risk of perioperative arterial occlusion and restenosis. It is unclear whether this reduces the risk of death or stroke.

Barriers to participation in randomised controlled trials: a systematic review

METHOD

A systematic review of three bibliographic databases from 1986 to 1996 identified 78 papers reporting barriers to recruitment of clinicians and patients to randomised controlled trials.

RESULTS

Clinician barriers included: time constraints, lack of staff and training, worry about the impact on the doctor-patient relationship, concern for patients, loss of professional autonomy, difficulty with the consent procedure, lack of rewards and recognition, and an insufficiently interesting question. Patient barriers included: additional demands of the trial, patient preferences, worry caused by uncertainty, and concerns about information and consent.

CONCLUSIONS

To overcome barriers to clinician recruitment, the trial should address an important research question and the protocol and data collection should be as straightforward as possible. The demands on clinicians and patients should be kept to a minimum. Dedicated research staff may be required to support clinical staff and patients. The recruitment aspects of a randomised controlled trial should be carefully planned and piloted. Further work is needed to quantify the extent of problems associated with clinician and patient participation, and proper evaluation is required of strategies to overcome barriers.

Treating neurocysticercosis medically: a systematic review of randomized, controlled trials

OBJECTIVE

To summarize the evidence from randomized controlled trials on the effects of cysticidal therapy used for treating human cysticercosis.

METHODS

Published and unpublished studies in any language identified through MEDLINE (1966 - June 1999) specialized databases, abstracts, proceedings and contact with experts were analysed. Those which compared, using randomized or quasi-randomized methods, any cysticidal drug with placebo or symptomatic therapy were entered in the study. Data were extracted independently by two reviewers and trial quality assessed. Meta-analysis using fixed effects models calculated provided there was no significant heterogeneity, expressed as relative risk.

RESULTS

Four trials met the inclusion criteria, treating intraparenchymatous neurocysticercosis with either albendazole or praziquantel compared to placebo or no treatment. In the two trials reporting clinical outcomes, treatment was not associated with a reduction in the risk of seizures, although numbers were small (RR 0.95, 95% CI 0.59-1.51). Four trials reported radiological outcomes, and cysticidal treatment was associated with a lower risk of cyst persistence of scans taken within six months of start of treatment (RR 0.83, 95% CI 0.70-0.99). Subsidiary analysis assuming different outcomes in patients lost to follow-up did not alter the findings of the main analysis.

CONCLUSIONS

There is insufficient evidence to determine whether cysticidal therapy is of any clinical benefit to patients with neurocysticercosis. The review does not exclude the possibility that more patients remain seizure-free when treated with cysticidal drugs. Further testing through placebo-controlled trials is required.

Reports of randomized trials in acute stroke, 1955 to 1995. What proportions were commercially sponsored?

BACKGROUND AND PURPOSE

Research in acute stroke has expanded rapidly. Many potentially important interventions lack commercial potential (eg, admission to a stroke unit). We therefore wished to examine the frequency of reports of randomized trials of interventions for acute stroke over the past 40 years, the source of support for such trials, the reporting of the commercial involvement, and whether the proportion of commercially supported trials had changed.

METHODS

Eligible trials were identified from the Cochrane Stroke Group's specialized register of controlled clinical trials. We included all randomized trials in patients with acute stroke which published a full text report, in English, between 1955 and 1995. Two reviewers independently extracted data on the involvement of the pharmaceutical industry in all eligible trials.

RESULTS

There was a substantial increase in the number of acute stroke trials published per year between 1955 and 1995. The description of pharmaceutical industry involvement in each trial report was poor. Only a minority of supported trials made explicit statements about the role of the sponsoring company. The proportion of trials apparently supported by the pharmaceutical industry has increased substantially.

CONCLUSIONS

The increasingly important role of the pharmaceutical industry in evaluating new treatments gives substantial scope for bias and may not be in the interests of public health. Poor reporting of the sponsor's involvement suggests that modifications to the guidelines for the reporting of randomized controlled trials to include more details of the sponsor's involvement in the design, conduct, management, analysis, and reporting of the trial are justified.

Implementation of a nurse practitioner role in an acute care setting

During the implementation, the authors strived to clearly identify a person to focus on patient outcomes. Thus, they limited the ARNP's involvement in central functions and direct management of the staff. The overall implementation of the demonstration project has benefited patients, staff, and the health care team. The continuity provided allows the patient and family to interact with a consistent person. The ARNP functions as the key to directing patient care in a holistic manner while facilitating staff development. The demonstration project has given the authors an opportunity to evaluate the management structure and redefine roles to achieve those outcomes in the management arena.

Planned change to implement a restraint reduction program

Physical restraints have been the standard of practice to manage certain types of patient behavior, such as unstable mobility, wandering, agitation, and interference with medical treatment. However, this intervention is not without serious negative consequences. Patients with neurological disorders or injuries are often at high risk for being restrained. The need to change to a more positive, patient-focused, restraint-free model was the goal of this project. A convenience sample of adult patients who were admitted to a neurological unit were studied. Outcome data that were assessed included (1) staff nurses' perception of restraints, (2) fall rate, (3) fall rate with injury, and (4) tube/line loss rate. Staff perceptions of restraints were assessed by administering the Perception of Restraints Use Questionnaire (PRUQ) before and after implementation of the restraint-reduced environment. The results of the outcome data support the change to a more restraint-reduced environment, as indicated by fall rate, fall rate with injury, and tube/line loss. Additionally, nurses' perceptions of restraints, as measured by the PRUQ, indicated a trend toward less emphasis on the use of restraints to control specific unsafe or undesirable patient behaviors.

Vagus nerve stimulator as a treatment for intractable epilepsy

Vagus nerve stimulation was recently approved for control of medically intractable seizures. This therapy provides some relief of seizures for selective patients, however seizure freedom using this device is uncommon. Vagus nerve stimulation appears to work by calming "hyperexcited" nerve cells and reverting brain activity to its normal patterns. Many people do have significant relief in the intensity and duration of their seizures and report improved quality of life using this device.

Is visible infarction on computed tomography associated with an adverse prognosis in acute ischemic stroke?

BACKGROUND AND PURPOSE

It is unclear whether visible infarction on a CT scan at any time after the stroke is an adverse prognostic factor once other factors such as stroke severity are taken into consideration. We examined whether visible infarction was associated with a poor outcome after stroke using univariate and multivariate analyses, including easily identifiable clinical baseline variables, and adjusting for time from stroke onset to CT.

METHODS

All inpatients and outpatients with an acute ischemic stroke attending our hospital stroke service were examined by a stroke physician and entered into a register prospectively. The CT scan was coded prospectively for the site and size of any relevant recent visible infarct. The patients were followed up at 6 months to ascertain their functional status with the use of the modified Rankin Scale. Analyses of the effect of visible infarction on the outcomes "dead or dependent" or "dead" at 6 months were performed with adjustment for time from stroke to CT, clinical stroke type (lacunar, hemispheric, or posterior circulation), and in a multiple logistic regression model to adjust for confounding baseline variables such as stroke severity.

RESULTS

In 993 patients in the stroke registry, visible infarction increased the risk of being dead or dependent at 6 months (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.9 to 3.3) or dead (OR, 4.5; 95% CI, 2.7 to 7.5), both on its own and after adjustment for time from stroke to CT, stroke symptoms, and other important clinical prognostic variables (OR for death or dependence in the predictive model, 1.5; 95% CI, 1.0 to 2.0; OR for death, 2.4; 95% CI, 1.4 to 4.1).

CONCLUSIONS

Visible infarction on CT is an adverse prognostic indicator (albeit of borderline significance) even after adjustment for stroke severity and time lapse between the stroke and the CT scan.

Assessment of clinical outcomes in acute stroke trials

BACKGROUND AND PURPOSE

Adequate outcome assessment is crucial to randomized trials. We wished to assess the types of outcomes used in acute stroke trials and the appropriateness of these outcomes and their analyses.

METHODS

Acute stroke trials from the Cochrane Stroke Group's database were included from 1955 to 1995 if they were published in full text in English. For each trial we collected year of publication, number of patients randomized, blinding of outcome assessment, the specific outcome instruments used, the statistical methods used for analysis, and the significance of the results. The validity and reliability of each outcome measure were assessed by review of the literature.

RESULTS

Our study included 174 trials. Outcomes were assessed blindly in 69%. Death was recorded in only 76% of trials, impairment in 76%, disability in 42%, and handicap or quality of life in only 2%. Of the trials that measured impairment, 35% used a measure of established validity or reliability. For disability and handicap, the proportions with valid or reliable measures were 70% and 25%, respectively. Impairment and handicap measures were primarily analyzed as continuous variables, while disability was mainly analyzed as a dichotomous variable. Continuous data were usually analyzed with inappropriate parametric statistics. There was no relationship between the method of analysis, the type of outcome, and the statistical significance of results.

CONCLUSIONS

Most acute stroke trials up to 1995 have used clinical outcome measures that were inadequate in terms of their content, reliability, validity, blinded assessment, and statistical analysis. This has important implications for future stroke research.

A systematic review of randomized evidence for fibrinogen-depleting agents in acute ischemic stroke

OBJECTIVE

To assess the efficacy and safety of fibrinogen-depleting agents (snake venom extracts) in the treatment of acute ischemic stroke.

METHODS

A systematic review of all the relevant randomized controlled trials (RCTs) was performed. RCTs were identified from the Cochrane Stroke Group's Specialized Trial Register, additional electronic and hand searching, and personal contact with pharmaceutical companies. We included all completed and unconfounded truly or quasi-randomized trials in patients with ischemic stroke comparing fibrinogen depleting agents with control started within 14 days of the stroke onset. The Peto method was used for analysis.

RESULTS

Eight completed and two ongoing RCTs have been identified so far. Only three trials using ancrod (182 patients) met the inclusion criteria. Ancrod was associated with a significant reduction in early deaths (5.6% v 16%; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.13 to 0.85; 2P=.02) suggesting that treatment of 100 patients would avoid about 10 early deaths. The frequency of asymptomatic intracranial hemorrhage shown by computed tomography was similar between ancrod-treated and control groups (7.6% v 9.6%; OR, 0.78; 95% CI, 0.26 to 2.33; 2P=.65). No major intracranial or extracranial hemorrhages or recurrent ischemic strokes occurred in the ancrod-allocated patients. There were nonsignificant trends in favor of ancrod in death from any cause (OR, 0.57; 95% CI, 0.27 to 1.23; 2P=.15) and death or disability (OR, 0.52; 95% CI, 0.26 to 1.03; 2P=.06) at the end of trial follow-up.

CONCLUSIONS

There were too few patients and outcome events to draw reliable conclusions from the present data. Although ancrod-like agents appeared promising, their routine use cannot be recommended at the moment. Two ongoing trials (including about 1,000 patients in total) will provide more data. Future trials should test simpler fixed-dose regimens to allow better generalizability.

Formulating questions and locating primary studies for inclusion in systematic reviews

Much time and effort are spent on designing primary research studies. Similar care must be given to planning systematic reviews. The review should be based on an important, well-focused question that is relevant to patient care. By formulating the question properly, the criteria that primary studies must meet to be included in the review become clear. These criteria, which comprise the types of persons involved, exposure, control group, outcomes, and study designs of interest, can then be refined so that they are clinically relevant, sensible, and workable. Inclusion criteria that are too narrow will limit the amount of data in the review, thereby increasing the risk for chance results and making the review less useful for the reader. Reviews should include studies whose designs offer the least biased answer to the question being asked. To maximize available data and reduce the risk for bias, as many relevant studies as possible need to be identified, regardless of publication status or language. Multiple overlapping search strategies should therefore be used and must be carefully planned. Strategies include searching the many electronic databases available (after careful consideration of which terms to enter), manually searching journals and conference proceedings, searching bibliographies of articles, searching existing registers of studies, and contacting companies or researchers. The time taken to formulate the question adequately and develop appropriate searches will increase the chance of producing a high-quality, meaningful review.

Systematic review of evidence on thrombolytic therapy for acute ischaemic stroke

BACKGROUND

Recent trials of thrombolytic therapy in acute ischaemic stroke have given apparently conflicting results. Only one trial, the National Institute of Neurological Disorders and Stroke trial of tissue plasminogen activator (tPA), suggested that thrombolysis was definitely beneficial. To make sense of these results, we have done a systematic review of all available randomised trials of thrombolysis in acute ischaemic stroke.

METHODS

From all available completed randomised trials of thrombolytic therapy compared with control in acute ischaemic stroke (with prerandomisation CT), we checked tabular data on deaths during roughly the first 2 weeks, deaths from all causes and functional outcome (disability) at the end of the trial follow-up period, and early symptomatic and fatal intracranial haemorrhages.

FINDINGS

12 trials included 3435 patients, of whom 694 (20%) were dead and 1001 (39%) of 2567 were functionally dependent at the end of follow-up (duration of follow-up varied between trials, but the longest was 6 months). 214 (6%) of the 3435 patients had early symptomatic or fatal intracranial haemorrhages. Thrombolytic therapy was associated with a significant excess of early deaths (91 per 1000 patients treated [95% CI 54-134]), and total deaths (37 per 1000 [20-83]), but there was nevertheless a significant reduction in the number of patients in the combined outcome of dead or dependent (65 fewer per 1000 patients treated [28-107]). There was a substantial and significant excess of symptomatic and fatal intracranial haemorrhages with thrombolysis-which was similar in all recent trials-of about 70 extra symptomatic intracranial haemorrhages per 1000 patients treated (of which 51 per 1000 were fatal). In the cohort of patients randomised within 3 h of stroke, there was a significant reduction in the number of patients who were dead or dependent at the end of follow-up (141 fewer dead or dependent per 1000 patients treated [75-206] and a non-significant increase in the number dead (nine per 1000 treated [-39 to 70]). There was significant heterogeneity between the trials for total deaths at the end of follow-up, which may be partly explained by differences in the use of antithrombotic drugs within the first 24 h of thrombolysis; the variation in severity of strokes included: the time window to thrombolytic treatment; and the dose of thrombolytic drug used. There were no direct comparisons of tPA with streptokinase or urokinase: much of the poor outcome in the streptokinase-treated patients might be explained by the inclusion of more severe strokes, greater use of antithrombotic drugs, higher doses, and the longer time to treatment compared with the trials that used tPA.

INTERPRETATION

Thrombolysis requires further testing in large randomised trials because the risks seem substantial, and the benefit uncertain. The time window for effective treatment remains unclear. There is no objective evidence to suggest that tPA is safer than streptokinase; the apparent hazards and benefits may be similar when differences in trial design and baseline variables are accounted for.