Ontario health technology assessment series
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Ont Health Technol Assess Ser · Jan 2010
Neuroimaging for the evaluation of chronic headaches: an evidence-based analysis.
The objectives of this evidence based review are: i) To determine the effectiveness of computed tomography (CT) and magnetic resonance imaging (MRI) scans in the evaluation of persons with a chronic headache and a normal neurological examination.ii) To determine the comparative effectiveness of CT and MRI scans for detecting significant intracranial abnormalities in persons with chronic headache and a normal neurological exam.iii) To determine the budget impact of CT and MRI scans for persons with a chronic headache and a normal neurological exam. ⋯ One systematic review, 1 small RCT, and 1 observational study met the inclusion and exclusion criteria. The systematic review completed by Detsky, et al. reported the likelihood ratios of specific clinical variables to predict significant intracranial abnormalities. The RCT completed by Howard et al., evaluated whether neuroimaging persons with chronic headache increased or reduced patient anxiety. The prospective observational study by Sempere et al., provided evidence for the pre-test probability of intracranial abnormalities in persons with chronic headache as well as minimal data on the comparative effectiveness of CT and MRI to detect intracranial abnormalities. OUTCOME 1: PRE-TEST PROBABILITY. The pre-test probability is usually related to the prevalence of the disease and can be adjusted depending on the characteristics of the population. The study by Sempere et al. determined the pre-test probability (prevalence) of significant intracranial abnormalities in persons with chronic headaches defined as headache experienced for at least a 4 week duration with a normal neurological exam. There is a pre-test probability of 0.9% (95% CI 0.5, 1.4) in persons with chronic headache and normal neurological exam. The highest pre-test probability of 5 found in persons with cluster headaches. The second highest, that of 3.7, was reported in persons with indeterminate type headache. There was a 0.75% rate of incidental findings. LIKELIHOOD RATIOS FOR DETECTING A SIGNIFICANT ABNORMALITY: Clinical findings from the history and physical may be used as screening test to predict abnormalities on neuroimaging. The extent to which the clinical variable may be a good predictive variable can be captured by reporting its likelihood ratio. The likelihood ratio provides an estimate of how much a test result will change the odds of having a disease or condition. The positive likelihood ratio (LR+) tells you how much the odds of having the disease increases when a test is positive. The negative likelihood ratio (LR-) tells you how much the odds of having the disease decreases when the test is negative. Detsky et al., determined the likelihood ratio for specific clinical variable from 11 studies. There were 4 clinical variables with both statistically significant positive and negative likelihood ratios. These included: abnormal neurological exam (LR+ 5.3, LR- 0.72), undefined headache (LR+ 3.8, LR- 0.66), headache aggravated by exertion or valsalva (LR+ 2.3, LR- 0.70), and headache with vomiting (LR+ 1.8, and LR- 0.47). There were two clinical variables with a statistically significant positive likelihood ratio and non significant negative likelihood ratio. These included: cluster-type headache (LR+ 11, LR- 0.95), and headache with aura (LR+ 12.9, LR- 0.52). Finally, there were 8 clinical variables with both statistically non significant positive and negative likelihood ratios. These included: headache with focal symptoms, new onset headache, quick onset headache, worsening headache, male gender, headache with nausea, increased headache severity, and migraine type headache. OUTCOME 2: RELIEF FROM ANXIETY Howard et al. completed an RCT of 150 persons to determine if neuroimaging for headaches was anxiolytic or anxiogenic. Persons were randomized to receiving either an MRI scan or no scan for investigation of their headache. The study population was stratified into those persons with a Hospital Anxiety and Depression scale (HADS) > 11 (the high anxiety and depression group) and those < 11 (the low anxiety and depression) so that there were 4 groups: Group 1: High anxiety and depression, no scan group Group 2: High anxiety and depression, scan group Group 3: Low anxiety and depression, no scan group Group 4: Low anxiety and depression, scan group ANXIETY: There was no evidence for any overall reduction in anxiety at 1 year as measured by a visual analogue scale of 'level of worry' when analysed by whether the person received a scan or not. Similarly, there was no interaction between anxiety and depression status and whether a scan was offered or not on patient anxiety. Anxiety did not decrease at 1 year to any statistically significant degree in the high anxiety and depression group (HADS positive) compared with the low anxiety and depression group (HADS negative). There are serious methodological limitations in this study design which may have contributed to these negative results. First, when considering the comparison of 'scan' vs. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2010
Cardiac magnetic resonance imaging for the diagnosis of coronary artery disease: an evidence-based analysis.
In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website).The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.htmlSINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY WITH CONTRAST FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based Analysis64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based AnalysisCARDIAC MAGNETIC RESONANCE IMAGING FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisPease note that two related evidence-based analyses of non-invasive cardiac imaging technologies for the assessment of myocardial viability are also available on the MAS website:POSITRON EMISSION TOMOGRAPHY FOR THE ASSESSMENT OF MYOCARDIAL VIABILITY: An Evidence-Based AnalysisMAGNETIC RESONANCE IMAGING FOR THE ASSESSMENT OF MYOCARDIAL VIABILITY: an Evidence-Based AnalysisThe Toronto Health Economics and Technology Assessment Collaborative has also produced an associated economic report entitled:The Relative Cost-effectiveness of Five Non-invasive Cardiac Imaging Technologies for Diagnosing Coronary Artery Disease in Ontario [Internet]. Available from: http://theta.utoronto.ca/reports/?id=7 OBJECTIVE: The objective of this analysis was to determine the diagnostic accuracy of cardiac magnetic resonance imaging (MRI) for the diagnosis of patients with known/suspected coronary artery disease (CAD) compared to coronary angiography. ⋯ The quality of the body of evidence was assessed according to the GRADE Working Group criteria for diagnostic tests. For perfusion analysis, the overall quality was determined to be low and for wall motion analysis the overall quality was very low.
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Ont Health Technol Assess Ser · Jan 2010
64-slice computed tomographic angiography for the diagnosis of intermediate risk coronary artery disease: an evidence-based analysis.
In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website).The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html ⋯ Non-English studies.Pediatric populations.Studies of patients at low or high pre-test probability of CAD.Studies of unstable patients, e.g., emergency room visits, or a prior diagnosis of CAD.Studies in patients with non-ischemic heart disease.Studies in which outcomes were not specific to those of interest in this report.Studies in which CTA was not compared to CA in a stable population. OUTCOMES OF INTEREST): CAD defined as ≥50% stenosis. COMPARATOR: Coronary angiography. MEASURES OF INTEREST: Sensitivity, specificity;Negative predictive value (NPV), positive predictive value (PPV);Area under the curve (AUC) and diagnostic odds ratios (DOR). RESULTS OF LITERATURE SEARCH AND EVIDENCE-BASED ANALYSIS: The literature search yielded two HTAs, the first published by MAS in April 2005, the other from the Belgian Health Care Knowledge Centre published in 2008, as well as three recent non-randomized clinical studies. The three most significant studies concerning the accuracy of CTA versus CA are the CORE-64 study, the ACCURACY trial, and a prospective, multicenter, multivendor study conducted in the Netherlands. Five additional non-randomized studies were extracted from the Belgian Health Technology Assessment (2008). (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2010
Percutaneous vertebroplasty for treatment of painful osteoporotic vertebral compression fractures: an evidence-based analysis.
OBJECTIVE OF ANALYSIS: The objective of this analysis is to examine the safety and effectiveness of percutaneous vertebroplasty for treatment of osteoporotic vertebral compression fractures (VCFs) compared with conservative treatment. ⋯ Recently, the results of two blinded randomized placebo-controlled trials of percutaneous vertebroplasty were reported. These trials, providing the highest quality of evidence available to date, do not support the use of vertebroplasty in patients with painful osteoporotic vertebral compression fractures. Based on the results of these trials, vertebroplasty offer no additional benefit over usual care and is not risk free. In these trials the treatment allocation was blinded to the patients and outcome assessors. The control group received a sham procedure simulating vertebroplasty to minimize the effect of expectations and to reduce the potential for bias in self-reporting of outcomes. Both trials applied stringent exclusion criteria so that the results are generalizable to the patient populations that are candidates for vertebroplasty. In both trials vertebroplasty procedures were performed by highly skilled interventionists. Multiple valid outcome measures including pain, physical, mental, and social function were employed to test the between group differences in outcomes. Prior to these two trials, there were two open randomized trials in which vertebroplasty was compared with conservative medical treatment. In the first randomized trial, patients were allowed to cross over to the other arm and had to be stopped after two weeks due to the high numbers of patients crossing over. The other study did not allow cross over and recently published the results of 12 months follow-up. The following is the summary of the results of these 4 trials: Two blinded RCTs on vertebroplasty provide the highest level of evidence available to date. Results of these two trials are supported by findings of an open randomized trial with 12 months follow-up. Blinded RCTs showed: No significant differences in pain scores of patients who received vertebroplasty and patients who received a sham procedure as measured at 3 days, 2 weeks and 1 month in one study and at 1 week, 1 month, 3 months, and 6 months in the other.The observed differences in pain scores between the two groups were neither statistically significant nor clinically important at any time points.The above findings were consistent with the findings of an open RCT in which patients were followed for 12 months. This study showed that improvement in pain was similar between the two groups at 3 months and were sustained to 12 months.In the blinded RCTs, physical, mental, and social functioning were measured at the above time points using 4-5 of the following 7 instruments: RDQ, EQ-5D, SF-36 PCS, SF-36 MCS, AQoL, QUALEFFO, SOF-ADLThere were no significant differences in any of these measures between patients who received vertebroplasty and patients who received a sham procedure at any of the above time points (with a few exceptions in favour of control intervention).These findings were also consistent with the findings of an open RCT which demonstrated no significant between group differences in scores of ED-5Q, SF-36 PCS, SF 36 MCS, DPQ, Barthel, and MMSE which measure physical, mental, and social functioning (with a few exceptions in favour of control intervention).One small (n=34) open RCT with a two week follow-up detected a significantly higher improvement in pain scores at 1 day after the intervention in vertebroplasty group compared with conservative treatment group. However, at 2 weeks follow-up, this difference was smaller and was not statistically significant.Conservative treatment was associated with fewer clinically important complicationsRisk of new VCFs following vertebroplasty was higher than those in conservative treatment but it requires further investigation.
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Ont Health Technol Assess Ser · Jan 2010
Extracorporeal lung support technologies - bridge to recovery and bridge to lung transplantation in adult patients: an evidence-based analysis.
For cases of acute respiratory distress syndrome (ARDS) and progressive chronic respiratory failure, the first choice or treatment is mechanical ventilation. For decades, this method has been used to support critically ill patients in respiratory failure. Despite its life-saving potential, however, several experimental and clinical studies have suggested that ventilator-induced lung injury can adversely affect the lungs and patient outcomes. Current opinion is that by reducing the pressure and volume of gas delivered to the lungs during mechanical ventilation, the stress applied to the lungs is eased, enabling them to rest and recover. In addition, mechanical ventilation may fail to provide adequate gas exchange, thus patients may suffer from severe hypoxia and hypercapnea. For these reasons, extracorporeal lung support technologies may play an important role in the clinical management of patients with lung failure, allowing not only the transfer of oxygen and carbon dioxide (CO(2)) but also buying the lungs the time needed to rest and heal. ⋯ TRIALS ON ILA: Of the seven studies identified, six involved patients with ARDS caused by a range of underlying conditions; the seventh included only patients awaiting LTx. All studies reported the rate of gas exchange and respiratory mechanics before ILA and for up to 7 days of ILA therapy. Four studies reported the means and standard deviations of blood gas transfer and arterial blood pH, which were used for meta-analysis. Fischer et al. reported their first experience on the use of ILA as a bridge to LTx. In their study, 12 patients at high urgency status for LTx, who also had severe ventilation refractory hypercapnea and respiratory acidosis, were connected to ILA prior to LTx. Seven patients had a systemic infection or sepsis prior to ILA insertion. Six hours after initiation of ILA, the partial pressure of CO(2) in arterial blood significantly decreased (P < .05) and arterial blood pH significantly improved (P < .05) and remained stable for one week (last time point reported). (ABSTRACT TRUNCATED)