Ontario health technology assessment series
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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)
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Ont Health Technol Assess Ser · Jan 2005
Physiotherapy rehabilitation after total knee or hip replacement: an evidence-based analysis.
The objective of this health technology policy analysis was to determine, where, how, and when physiotherapy services are best delivered to optimize functional outcomes for patients after they undergo primary (first-time) total hip replacement or total knee replacement, and to determine the Ontario-specific economic impact of the best delivery strategy. The objectives of the systematic review were as follows: To determine the effectiveness of inpatient physiotherapy after discharge from an acute care hospital compared with outpatient physiotherapy delivered in either a clinic-based or home-based setting for primary total joint replacement patientsTo determine the effectiveness of outpatient physiotherapy delivered by a physiotherapist in either a clinic-based or home-based setting in addition to a home exercise program compared with a home exercise program alone for primary total joint replacement patientsTo determine the effectiveness of preoperative exercise for people who are scheduled to receive primary total knee or hip replacement surgery ⋯ Based on the evidence, the Medical Advisory Secretariat reached the following conclusions with respect to physiotherapy rehabilitation and physical functioning 1 year after primary TKR or THR surgery: There is high-quality evidence from 1 large RCT to support the use of home-based physiotherapy instead of inpatient physiotherapy after primary THR or TKR surgery.There is low-to-moderate quality evidence from 1 large RCT to support the conclusion that receiving a monitoring phone call from a physiotherapist and practising home exercises is comparable to receiving clinic-based physiotherapy and practising home exercises for people who have had primary TKR surgery. However, results may not be generalizable to those who have had THR surgery.There is moderate evidence to suggest that an exercise program beginning 4 to 6 weeks before primary TKR surgery is not effective. (ABSTRACT TRUNCATED)
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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)