Ontario health technology assessment series
-
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.
-
Ont Health Technol Assess Ser · Jan 2005
Use of automated external defibrillators in cardiac arrest: an evidence-based analysis.
The objectives were to identify the components of a program to deliver early defibrillation that optimizes the effectiveness of automated external defibrillators (AEDs) in out-of-hospital and hospital settings, to determine whether AEDs are cost-effective, and if cost-effectiveness was determined, to advise on how they should be distributed in Ontario. ⋯ The OPALS study model appears cost-effective, and effectiveness can be further enhanced by training community volunteers to improve the bystander-initiated CPR rates. Deployment of AEDs in all public access areas and in houses and apartments is not cost-effective. Further research is needed to examine the benefit of in-home use of AEDs in patients at high risk of cardiac arrest.
-
Ont Health Technol Assess Ser · Jan 2005
Osteogenic protein-1 for long bone nonunion: an evidence-based analysis.
To assess the efficacy of osteogenic protein-1 (OP-1) for long bone nonunion. ⋯ Friedlaender et al. conducted a prospective, randomized, partially blinded clinical trial on the treatment tibial nonunions with OP-1. Tibial nonunions were chosen for this study because of their high frequency, challenging treatment requirements, and substantial morbidity. All of the nonunions were at least 9 months old and had shown no progress toward healing over the previous 3 months. The patients were randomized to receive either treatment with autologous bone grafting or treatment with OP-1 in a type-1 collagen carrier. Both groups received reduction and fixation with an intramedullary rod. Table 1 summarizes the clinical outcomes of this study. Table 1:Outcomes in a Randomized Clinical Trial on Tibial Nonunions: Osteogenic Protein-1 versus Autologous Bone GraftingClinical Indicator at 9 monthsSuccess by ProcedureOP-1 % (range)Autograft % (range)PWeight-bearing*8685not significantPain on Weight-bearing*8990not significantBridging seen on radiograph (at least 1 view)7584not significantBridging seen on radiograph (at least 3 views)6274not significantRepeated surgery*510not significantPhysician satisfaction8690not significantMean operative time in minutes (range)169 (58 - 420)178 (58 - 420)not significantMean operative blood loss in ml (range)254 (10-1,150)345 (35 - 1,200).049Mean length of stay in days (range)3.7 (0 - 18)4.1 (1 - 24)not significantPain at the donor siteN/A80N/AAt 6 months postsurgery20At 12 months postsurgery13Osteomyelitis % (number)3 (2/61)21 (13/61). (ABSTRACT TRUNCATED)
-
Ont Health Technol Assess Ser · Jan 2005
Hyperbaric oxygen therapy for non-healing ulcers in diabetes mellitus: an evidence-based analysis.
To examine the effectiveness and cost-effectiveness of hyperbaric oxygen therapy (HBOT) to treat people with diabetes mellitus (DM) and non-healing ulcers. This policy appraisal systematically reviews the published literature in the above patient population, and applies the results and conclusions of the review to current health care practices in Ontario, Canada. Although HBOT is an insured service in Ontario, the costs for the technical provision of this technology are not covered publicly outside the hospital setting. Moreover, access to this treatment is limited, because many hospitals do not offer it, or are not expanding capacity to meet the demand. ⋯ In 2003, the Ontario Health Technology Advisory Committee recommended a more coordinated strategy for wound care in Ontario to the Ministry of Health and Long-term Care. This strategy has begun at the community care and long-term care institution levels, but is pending in other areas of the health care system. There are about 700,000 people in Ontario with diabetes; of these, 10% to 15% may have a foot ulcer sometime in their lifetimes. Foot ulcers are treatable, however, when they are identified, diagnosed and treated early according to best practice guidelines. Routine follow-up for people with diabetes who may be at risk for neuropathy and/or peripheral vascular disease may prevent subsequent foot ulcers. There are 4 chambers that provide HBOT in Ontario. Fewer than 20 people with DM received HBOT in 2003. The quality of the evidence assessing the effectiveness of HBOT as an adjunct to standard therapy for people with non-healing diabetic foot ulcers is low, and the results are inconsistent. The results of a recent meta-analysis that found benefit of HBOT to prevent amputation are therefore uncertain. Future well-conducted studies may change the currently published estimates of effectiveness for wound healing and prevention of amputation using HBOT in the treatment of non-healing diabetic foot ulcers. Although HBOT is an insured service in Ontario, a well conducted, randomized controlled trial that has wound healing and amputation as the primary end-points is needed before this technology is used widely among patients with foot wounds due to diabetes.
-
Ont Health Technol Assess Ser · Jan 2005
Biventricular pacing (cardiac resynchronization therapy): an evidence-based analysis.
In 2002, (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on biventricular (BiV) pacing, also called cardiac resynchronization therapy (CRT). The goal of treatment with BiV pacing is to improve cardiac output for people in heart failure (HF) with conduction defect on ECG (wide QRS interval) by synchronizing ventricular contraction. The Medical Advisory Secretariat concluded that there was evidence of short (6 months) and longer-term (12 months) effectiveness in terms of cardiac function and quality of life (QoL). More recently, a hospital submitted an application to the Ontario Health Technology Advisory Committee to review CRT, and the Medical Advisory Secretariat subsequently updated its health technology assessment. ⋯ Owing to the limitations of drug therapy, cardiac transplantation and device therapies have been used to try to improve QoL and survival of patients with chronic HF. Ventricular pacing is an emerging treatment option for patients with severe HF that does not respond well to medical therapy. Traditionally, indications for pacing include bradyarrhythmia, sick sinus syndrome, atrioventricular block, and other indications, including combined sick sinus syndrome with atrioventricular block and neurocardiogenic syncope. Recently, BiV pacing as a new, adjuvant therapy for patients with chronic HF and mechanical dyssynchrony has been investigated. Ventricular dysfunction is a sign of HF; and, if associated with severe intraventricular conduction delay, it can cause dyssynchronous ventricular contractions resulting in decreased ventricular filling. The therapeutic intent is to activate both ventricles simultaneously, thereby improving the mechanical efficiency of the ventricles. About 30% of patients with chronic HF have intraventricular conduction defects. (6) These conduction abnormalities progress over time and lead to discoordinated contraction of an already hemodynamically compromised ventricle. Intraventricular conduction delay has been associated with clinical instability and an increased risk of death in patients with HF. (7) Hence, BiV pacing, which involves pacing left and right ventricles simultaneously, may provide a more coordinated pattern of ventricular contraction and thereby potentially reduce QRS duration, and intraventricular and interventricular asynchrony. People with advanced chronic HF, a wide QRS complex (i.e., the portion of the electrocardiogram comprising the Q, R, and S waves, together representing ventricular depolarization), low left ventricular ejection fraction and contraction dyssynchrony in a viable myocardium and normal sinus rhythm, are the target patients group for BiV pacing. One-half of all deaths in HF patients are sudden, and the mode of death is arrhythmic in most cases. Internal cardioverter defibrillators (ICDs) combined with BiV pacemakers are therefore being increasingly considered for patients with HF who are at high risk of sudden death. CURRENT IMPLANTATION TECHNIQUE FOR CARDIAC RESYNCHRONIZATION: Conventional dual-chamber pacemakers have only 2 leads: 1 placed in the right atrium and the other in the right ventricle. The technique used for BiV pacemaker implantation also uses right atrial and ventricular pacing leads, in addition to a left ventricle lead advanced through the coronary sinus into a vein that runs along the ventricular free wall. This permits simultaneous pacing of both ventricles to allow resynchronization of the left ventricle septum and free wall. MODE OF OPERATION: Permanent pacing systems consist of an implantable pulse generator that contains a battery and electronic circuitry, together with 1 (single-chamber pacemaker) or 2 (dual-chamber pacemaker) leads. Leads conduct intrinsic atrial or ventricular signals to the sensing circuitry and deliver the pulse generator charge to the myocardium (muscle of the heart). COMPLICATIONS OF BIVENTRICULAR PACEMAKER IMPLANTATION: The complications that may arise when a BiV pacemaker is implanted are similar to those that occur with standard pacemaker implantation, including pneumothorax, perforation of the great vessels or the myocardium, air embolus, infection, bleeding, and arrhythmias. Moreover, left ventricular pacing through the coronary sinus can be associated with rupture of the sinus as another complication. CONCLUSION OF 2003 REVIEW OF BIVENTRICULAR PACEMAKERS BY THE MEDICAL ADVISORY SECRETARIAT: The randomized controlled trials (RCTs) the Medical Advisory Secretariat retrieved analyzed chronic HF patients that were assessed for up to 6 months. Other studies have been prospective, but nonrandomized, not double-blinded, uncontrolled and/or have had a limited or uncalculated sample size. Short-term studies have focused on acute hemodynamic analyses. The authors of the RCTs reported improved cardiac function and QoL up to 6 months after BiV pacemaker implantation; therefore, there is level 1 evidence that patients in ventricular dyssynchrony who remain symptomatic after medication might benefit from this technology. Based on evidence made available to the Medical Advisory Secretariat by a manufacturer, (8) it appears that these 6-month improvements are maintained at 12-month follow-up. To date, however, there is insufficient evidence to support the routine use of combined ICD/BiV devices in patients with chronic HF with prolonged QRS intervals. SUMMARY OF UPDATED FINDINGS SINCE THE 2003 REVIEW: Since the Medical Advisory Secretariat's review in 2003 of biventricular pacemakers, 2 large RCTs have been published: COMPANION (9) and CARE-HF. (10) The characteristics of each trial are shown in Table 1. The COMPANION trial had a number of major methodological limitations compared with the CARE-HF trial. Table 1:Characteristics of the COMPANION and CARE-HF Trials*COMPANION, 2004CARE-HF, 2005Optimal Therapy vs. BiV Pacing vs. BiV Pacing/ICD†Optimal Therapy vs. BiV PacingPopulationNew York Heart Association class III/IV heart failureEF† ≤ 0.35QRS† ≥ 120 msN1,520(optimal therapy, n = 308; BiV pacing, n = 617; BiV pacing/ICD, n = 595)813Follow-up (months)Median, 16Mean, 29Comment- Definition of "hospitalization" in primary outcome changed 3 times during trial w/o documentation in protocol and FDA† not notified (dominant outcome for composite endpoint).- Dropouts/withdrawals/crossovers not clearly described.- Study terminated early.- No direct comparison between BiV pacing vs. BiV pacing/ICD.- High number of patients withdrew from optimal therapy to device arms.- Not blinded.Not blinded*COMPANION; (9) CARE-HF. (ABSTRACT TRUNCATED)