Ontario health technology assessment series
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Ont Health Technol Assess Ser · Jan 2005
Multi-detector computed tomography angiography for coronary artery disease: an evidence-based analysis.
Computed tomography (CT) scanning continues to be an important modality for the diagnosis of injury and disease, most notably for indications of the head and abdomen. (1) According to a recent report published by the Canadian Institutes of Health Information, (1) there were about 10.3 scanners per million people in Canada as of January 2004. Ontario had the fewest number of CT scanners per million compared to the other provinces (8 CT scanners per million). The wait time for CT in Ontario of 5 weeks approaches the Canadian median of 6 weeks. This health technology and policy appraisal systematically reviews the published literature on multidetector CT (MDCT) angiography as a diagnostic tool for the newest indication for CT, coronary artery disease (CAD), and will apply the results of the review to current health care practices in Ontario. This review does not evaluate MDCT to detect coronary calcification without contrast medium for CAD screening purposes. ⋯ Cardiac imaging is a relatively new indication for CT. A systematic review of the literature was performed from 2003 to January 2005 to determine the effectiveness of MDCT angiography (16-slice and 64-slice) compared to coronary angiography to detect CAD. At the time of this report, there was no published literature on 64-slice CT for any indications. Based on this review, the Medical Advisory Secretariat concluded that there is insufficient evidence to suggest that 16-slice or 64-slice CT angiography is equal to or better than coronary angiography to diagnose CAD in people with symptoms or to detect disease progression in patients who had previous cardiac interventions. An analysis of the evidence suggested that in investigating suspicion of CAD, a substantial number of patients would be missed. This means that these people would not be appropriately treated. These patients might progress to more severe disease and possibly more adverse events. Overall, the clinical utility of MDCT in patient management and long-term outcomes is unknown. Based on the current evidence, it is unlikely that CT angiography will replace coronary angiography completely, but will probably be used adjunctively with other cardiac diagnostic tests until more definitive evidence is published. If multi-slice CT scanners are used for coronary angiography in Ontario, access to the current compliment of CT scanners will necessarily increase wait times for general CT scanning. It is unlikely that these newer-generation scanners will improve patient throughput, despite the claim that they are faster. Screening for CAD in asymptomatic patients and who have no history of ischemic heart disease using any modality is not advised, based on the World Health Organization criteria for screening. Therefore, this review did not examine the use of multi-slice CT for this purpose.
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This health technology policy assessment will answer the following questions: When should in-room air cleaners be used?How effective are in-room air cleaners?Are in-room air cleaners that use combined HEPA and UVGI air cleaning technology more effective than those that use HEPA filtration alone?What is the Plasmacluster ion air purifier in the pandemic influenza preparation plan?The experience of severe acute respiratory syndrome (SARS) locally, nationally, and internationally underscored the importance of administrative, environmental, and personal protective infection control measures in health care facilities. In the aftermath of the SARS crisis, there was a need for a clearer understanding of Ontario's capacity to manage suspected or confirmed cases of airborne infectious diseases. In so doing, the Walker Commission thought that more attention should be paid to the potential use of new technologies such as in-room air cleaning units. It recommended that the Medical Advisory Secretariat of the Ontario Ministry of Health and Long-Term Care evaluate the appropriate use and effectiveness of such new technologies. Accordingly, the Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat to review the literature on the effectiveness and utility of in-room air cleaners that use high-efficiency particle air (HEPA) filters and ultraviolet germicidal irradiation (UVGI) air cleaning technology. Additionally, the Ontario Health Technology Advisory Committee prioritized a request from the ministry's Emergency Management Unit to investigate the possible role of the Plasmacluster ion air purifier manufactured by Sharp Electronics Corporation, in the pandemic influenza preparation plan. ⋯ There were no existing health technology assessments on air cleaning technology located during the literature review. The literature search yielded 59 citations of which none were retained. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2005
Implantable cardioverter defibrillators. Prophylactic use: an evidence-based analysis.
The use of implantable cardiac defibrillators (ICDs) to prevent sudden cardiac death (SCD) in patients resuscitated from cardiac arrest or documented dangerous ventricular arrhythmias (secondary prevention of SCD) is an insured service. In 2003 (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on the prophylactic use (primary prevention of SCD) of ICDs for patients at high risk of SCD. The Medical Advisory Secretariat concluded that ICDs are effective for the primary prevention of SCD. Moreover, it found that a more clearly defined target population at risk for SCD that would be likely to benefit from ICDs is needed, given that the number needed to treat (NNT) from recent studies is 13 to 18, and given that the per-unit cost of ICDs is $32,000, which means that the projected cost to Ontario is $770 million (Cdn). Accordingly, as part of an annual review and publication of more recent articles, the Medical Advisory Secretariat updated its health technology policy assessment of ICDs. ⋯ Using the GRADE Working Group criteria, the quality of these 3 trials was examined (Table 2). Quality refers to the criteria such as the adequacy of allocation concealment, blinding and follow-up. Consistency refers to the similarity of estimates of effect across studies. If there is important unexplained inconsistency in the results, our confidence in the estimate of effect for that outcome decreases. Differences in the direction of effect, the size of the differences in effect, and the significance of the differences guide the decision about whether important inconsistency exists. Directness refers to the extent to which the people interventions and outcome measures are similar to those of interest. For example, there may be uncertainty about the directness of the evidence if the people of interest are older, sicker or have more comorbidity than those in the studies. As stated by the GRADE Working Group, the following definitions were used to grade the quality of the evidence: HIGH: Further research is very unlikely to change our confidence n the estimate of effect.MODERATE: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.LOW: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.VERY LOW: Any estimate of effect is very uncertain.Table 2:Quality of Evidence - MADIT I, MADIT II, and SCD-HeFT*TrialDesignQualityConsistencyDirectness†Quality GradeMADIT IRCTImbalance in β-blocker usage between study arms.The overall number of patients from which the study was drawn was not reported.Selection bias may have occurred since patients were selected for randomization if they did not respond to procainamide, thereby introducing a potential bias into the medication arm.Specific details regarding allocation concealment and blinding procedures were not provided.Single-chamber ICD used in study.Trial started with transthoracic implants, and then switched to nontransthoracic implants.Ischemic cardiomyopathy only.5-year NNT = 2.The overall number of Moderate patients from which the study was drawn was not reported.Selection bias may have occurred since patients were selected for randomization if they did not respond to procainamide, thereby introducing a potential bias into the medication arm.ModerateMADIT IIRCT~ 90% of patients were recruited ≥6 months post-MI; 20% of control group died after mean 20-month follow-up.How and where patients recruited?Specific details regarding allocation concealment/blinding procedures not provided.Subset had MADIT I criteria; post hoc analysis of incomplete data suggested "weak-moderate evidence that ICD effect greater in inducible than noninducible patients in MADIT II." (5;6)First study to assess both single- and dual-chamber ICD devices for primary prevention.Programming of device and medications left to the discretion of the patients' physician.Higher rate of hospitalization for new or worsened heart failure in the group receiving the ICDs compared to conventional therapy (19.9% versus 14.9% respectively).Ischemic cardiomyopathy only.5-year NNT = 6.How and where patients Weak recruited?Subset had MADIT I criteria.WeakSCD-HeFTRCTStatistically significant difference in β-blocker usage between treatment groups at last follow-up.Drug arms double-blinded.Shock-only single-lead device. Antitachycardia pacing not permitted.Ischemic and nonischemic cardiomyopathy.There was a statistically significant difference in terms of the NYHA prespecified subgroups analysis. The NYHA subgroups were prespecified a priori and the results of the interaction tests were significant. Yet, ICD treatment had a significant benefit in patients in NYHA class II but not in those in NYHA class III. (ABSTRACT TRUNCATED)
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Ont Health Technol Assess Ser · Jan 2005
Spinal cord stimulation for neuropathic pain: an evidence-based analysis.
The objective of this health technology policy assessment was to determine the effectiveness of spinal cord stimulation (SCS) to manage chronic intractable neuropathic pain and to evaluate the adverse events and Ontario-specific economic profile of this technology. ⋯ SCS may be considered for patients with chronic, neuropathic pain for whom standard pain treatments have failed and when there is no indication for surgical intervention to treat the underlying condition.
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Ont Health Technol Assess Ser · Jan 2005
Positron emission tomography for the assessment of myocardial viability: an evidence-based analysis.
The objective was to update the 2001 systematic review conducted by the Institute For Clinical Evaluative Sciences (ICES) on the use of positron emission tomography (PET) in assessing myocardial viability. The update consisted of a review and analysis of the research evidence published since the 2001 ICES review to determine the effectiveness and cost-effectiveness of PET in detecting left ventricular (LV) viability and predicting patient outcomes after revascularization in comparison with other noninvasive techniques. ⋯ In patients with severe LV dysfunction, that are deemed to have no viable myocardium or indeterminate results in assessments using other noninvasive tests, PET may have a role in further identifying patients who may benefit from revascularization. No firm conclusion can be drawn on the impact of PET viability assessment on long-term clinical outcomes in the most important target population (i.e. patients with severe LV dysfunction).