Health Technology Assessment 2000; Vol. 4: No. 23
`
`
`
`Coronary artery stents in the
`treatment of ischaemic heart disease:
`
`a rapid and systematic review
`
`C Hyde
`
`C Meads
`
`C Cummins
`
`K Jolly
`
`A Stevens
`
`A Burls
`
`
`
`Health TechnologyAssessment
`
`NHS R&D HTA Programme
`
`I HTA
`4-
`
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`Standing Group on Health Technology
`
`Professor john Gahbay
`Director, Wessex Institute
`for Health Research
`8: Development
`
`Professor Sir‘loltn
`Grimley Evans
`Professor of Clinical Gelatology,
`Radcliffe Infirmary,
`Oxford
`
`Dr Tony Hope
`(:linieal Reader in Medicine.
`NuIlield Dcpartmcm of
`(Ilinieal Medicine.
`University of Oxford
`
`Professor Richard Lilford
`Regional Director of R820.
`NHS Executive \Nest Midlands
`
`Drjenemy Mettets
`Deputy Chief Medical ( )l'l'lccr,
`Department of Health
`
`Professor Maggie Pearson
`Regional Director of R851),
`NHS Executive. North West
`
`Mr Hugh Ross
`Chief Executive.
`The United Bristol
`I lealthcare .\'1 IS 'l‘rust
`Professor Trevor Sheldon
`Joint Director, York Health
`Policy Group. Uitireisity of York
`Professor Mike Smith
`Faculty Dean of Rese relt
`for Medicine, Dentistiy,
`Psychology 8:: Health,
`University of Leeds
`
`Drjohn Tripp
`Senior lecturer in (lllild
`Health, Royal Devon and Exeter
`lleallhrare NI IS Trust
`
`Professor Toni Walley
`Director.
`Prescribing Research Group,
`University of Liverpool
`
`Dl’JllllC W'oodin
`Chief Executive.
`Nottingham Health Authority
`
`Current members
`(Blair:
`Professor Kent Woods
`Professor of Therapeutics,
`University of Leicester
`
`Professor Martin Buxton
`Director 8.: Professor of
`Health Economics,
`Health Economics
`Research Group.
`Brunel University
`Professor Shah Ehrahim
`Professor of Epidemiology
`of Ageing, University of Bristol
`meessor Francis H Creed
`Professor of
`Psychological Medicine.
`Manchester Royal lnftrmaty
`
`Past members
`
`Professor Sir Miles Inving“
`Professor of 51"};er
`University of Manchester,
`[lop-e Hospital, ballot-d
`Dr Sheila Adam
`Department of] lealth
`
`Professor Angela Coulter
`Director, King‘s Fund,
`London
`
`Professor Anthony (lulyer
`DeputyI Vice-chancellor,
`Univeisity of York
`
`Professor‘lohn Farndon
`Professor of Surge“:
`University of Bristol
`
`Professor Charles Florey
`Department of Epidemiology
`8c Public Health. Ninewells
`Hospital &: Medical School.
`Uztitersity of Dundee
`Professor Howard
`Glennester
`Professor of Social Science
`8c Administration, London
`School ol’Economics 8r
`I'oliljcal Science
`
`Professor Michael Maisey
`Professor of
`Radiological Sciences,
`Guy‘s, King’s 8: SI 'l'homas’s
`School of Medicine 3: Dentistry.
`London
`
`Mrs Gloria Oates
`Chief Executive,
`()ldhant N115 Trust
`
`Dr George Poste
`Chief Science 8: Technology
`()ilieer. Smithlfiine lieecham
`
`Professor Michael Rawlins
`“’olfsnn Unit of
`Clinical Pharmacology,
`University of Newcastle-
`upon-Tyne
`
`Professor Martin Roland
`Professor of General Practice.
`University of Manchester
`Professor Ian Russell
`Depanmem or I [ealth Sciences
`3: Clinical Evaluation,
`University of York
`Dr Charles Swan
`Consultant Castmentemlogist.
`North Staffoiidshire
`Royal Infirmary
`
`' Previous Cltair
`
`Dr Peter Doyle
`Executive Director, Zeneca Ltd,
`ACOST C(llllllllttt't' on Medical
`Research 8: Health
`
`Mr‘Iohn Hjames
`Chief Executive,
`Kettsinglon, Chelsea 8:
`“'esllninster Health Authority'
`
`Details of the membership of the HTA panels, the NCCHTA Advisory Group and the HTA
`Commissioning Board are given at the end of this report.
`
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`
`
`1m?
`4- ',
`
`e
`INAHTA
`
`How to obtain copies of this and other HTA Programme reports.
`An electronic version of this publication. in Adobe Acrobat format. is available for downloading free of
`charge for personal use from the HTA website (http:/lwww.hta.ac.uk). A fully searchable CD-ROM is
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`
`
`Coronary artery stents in the
`
`treatment of ischaemic heart disease:
`
`a rapid and systematic review
`
`C Meads
`
`C Cummins
`
`K Jolly
`
`A Stevens
`
`A Burls
`
`C Hydel
`
`Department of Public Health and Epidemiology,
`
`University of Birmingham, UK
`:3
`
`Corresponding author
`
`Competing interests: none declared.
`
`Expiry date: I January 20C”
`
`Published November 2000
`
`
`
`This report should be referenced as follows:
`
`Meads C. Cummins C.]ol|y K. Stevens A, Bu rls A, Hyde C. Coronary artery stents in the
`treatment of ischaemic heart disease: a rapid and systematic review Health Technol Assess
`2000;4(23).
`
`Health Technology Assessment is indexed in index MedicuslMEDLlNE and Excerpta Medical
`EMBASE. Copies of the Executive Summaries are available from the NCCHTA website
`(see overleaf).
`
`
`
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`NHS R&D HTA Programme
`
`he overall aim of the NHS RSCD Health Technology Assessment (HTA) programme is to ensure
`that high-quality research information on the costs, effectiveness and broader impact of health
`technologies is produced in the most efficient way for those who use, manage and work in the NHS.
`Research is undertaken in those areas where the evidence will lead to the greatest benefits to
`patients, either through improved patient outcomes or the most efficient use of NHS resources.
`
`The Standing Group on Health Technology advises on national priorities for health technology
`assessment. Six advisory panels assist the Standing Group in identifying and prioritising projects.
`These priorities are then considered by the HTA Commissioning Board supported by the National
`Coordinating Centre for HTA (NCCHTA).
`
`The research reported in this monograph was commissioned by the HTA programme (project
`number 99/15/01) on behalf of the National Institute for Clinical Excellence (NICE). Rapid reviews
`are completed in a limited time to inform the appraisal and guideline development processes
`managed by NICE. The review brings together evidence on key aspects of the use of the technology
`concerned. However, appraisals and guidelines produced by NICE are informed by a wide range
`of sources. Any views expressed in this rapid review are therefore those of the authors and not
`necessarily those of the HTA programme, NICE. or the Department of Health.
`
`Reviews in Health Ethnology Assessment are termed ‘systematic’ when the account of the search,
`appraisal and synthesis methods [to minimise biases and random errors) would, in theory, permit
`the replication of the review by others.
`
`Criteria for inclusion in the HTA monograph series
`Reports are published in the HTA monograph series if(l} they have resulted from work either prioritised by the
`Standing Group on Health Technology. or otherwise commissioned for the HTA programme, and (2} they are of
`
`a sufficiently high scientific quality as assessed by the referees and editors.
`
`Series Editors: Andrew Stevens, Ken Stein and john Gabbay
`
`Monograph Editorial Manager: Melanie Corris
`
`The editors and publisher have tried to ensure the accuracy of this report bttt do not accept liability
`for damages or losses arising from material published in this review.
`
`ISSN 366-5278
`
`© Crown copyright 2000
`
`Enquiries relating to copyright should be addressed to the NCCHTA {see address given below).
`
`Published by Core Research, Alton, on behalf oi the NCCHTA.
`Printed on acid-free paper in the UK by The Basingstoke Press, Basingstoke.
`
`Copies of this report can be obtained from;
`
`The National Coordinating Centre for Health Technology Assessment,
`Mailpoint 723. Boldrewood.
`University of Southampton.
`Southampton. SOI 6 TPX. UK.
`Fax: +44 (0) 23 8059 5639
`http:llwww.ncchta.org
`
`Email: hta@soton.ac.uk
`
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`Health TechnologyAssessment 2000; Vol. 4: No. 23
`
`Contents
`
`Glossary and list of abbreviations
`
`Appendix I Manulacturers‘ submissions
`
`Executive summary
`
`Appendix 2 Ellectiveness search strategy
`
`Review aims and background
`Aims"
`Int1od1iction"
`Description ofhealtl’i problem
`
`Current sewice provision.
`Implications for the NHS
`
`Methods
`
`Review questions
`
`Search strategy ..........
`Inclusion and exclusion criteria
`
`l]
`11
`ll
`
`12
`
`(clinical eli'ectivcness)
`Inclusion and exclusion criteria
`.
`(economic evaluation)...
`Data abstraction (clinical ellectiveness} .......
`Data abstraction (economic evaluation) ......
`Quality assessment (clinical efi'ectiveness)
`Quality assessment (economic evaluation)...
`Data synthesis (clinical ellectiveness}
`
`Data synthesis (economic evaluation)
`
`13
`13
`13
`13
`13
`
`Results
`Introduction ...........
`
`Ellectiveness results ...............
`
`Results of economic evaluatlons review .......
`
`Discussion and conclusions
`
`
`...
`Results summary...
`.
`Potential methodological strengths and
`weaknesses of the technology assessment
`Conclusions
`
`
`ssessment findings
`Implications of a
`
`Acknowledgements
`
`References
`
`49
`
`51
`
`iii
`
`65
`
`(i7
`
`Appendix 3 Cost search strategy
`
`Appendix 4 Economic evaluation
`search strategy
`
`Appendix 5 Tables of results of review
`ofeffectiveness
`
`Appendix 6 PICA costs
`
`Appendix 7 Stents t‘.osts....
`
`.
`
`.
`
`.
`
`Appendix 8 CABLE costs
`
`Appendix9mStudy"types of economic
`analyses...
`..
`
`Appendix ID Summary table ol’economic
`analyses (models)
`
`129
`
`Appendix I I Summary of economic
`analyses (individual studies)
`
`133
`
`Appendix I2 Source of cost data for
`economic analyses
`
`137
`
`Appendix I3 Outcome measures reported
`by individual economic analyses
`
`139
`
`Appendix I4 Quality assessment of
`included economic studies
`
`Health Technology Assessment reports
`published to date
`
`141
`
`145
`
`Health Technology Assessment
`panel membership
`
`149
`
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`Health TechnologyAssessment 2000; Vol. 4: No. 23
`
`Glossary and list of abbreviations
`
`Technical terms and abbreviations are used throughout this report. The meaning is usually clear from
`the context but a glossary is provided for the non—specialist reader. In some cases usage clilfers in the
`literature but the term has a constant meaning til roughoul this review.
`
`Glossary
`Abciximab A glycoprotein llb/llla
`antagonist, used to inhibit blood clotting.
`
`Acute coronary syndrome Severe
`symptomatic coronary artery disease
`including unstable angina and non-Q wave
`myocardial infarction.
`
`ECG Electrocardiogram — maps electrical
`activity in the heart muscle. ECG findings
`might include Qwaves or ST elevation
`
`Exercise stress test Diagnostic test used to
`find exercise-induced ECG changes indicating
`myocardial ischaemia
`
`Angina Pain in the heart muscle due to lack
`ol'blood—borne oxygen, it is usually induced
`by exercise and relieved by rest.
`
`Angiography Radiographic technique using
`contrast medium to shotsr outline of coronary
`artery lumens.
`
`Elective Non-emergency treatment.
`
`Insertion oi'graft
`Graft (saphenous vein)
`vessel into coronary artery during coronary
`artery bypass grafting (CABG).
`
`Heterogeneity Variability or dillerences
`between studies.
`
`
`
`Angioplasty Short for pereutaneous
`transluminal coronary angioplasty {PTCA).
`
`Atherosclerosis A disease of the arteries
`
`in which fatty plaques develop on their
`inner walls leading to reduced blood flow
`or obstruction.
`
`Bailout stent Stent inserted as an emergency
`(luring PTCA because of dissection of the
`vessel wall.
`
`Braunwald Classification Classification of
`
`unstable angina.
`
`Cardiac catheterisation Passing a catheter
`from femoral artery into coronary arteries
`for angiography or percutaneous coronary
`intervention (PCI).
`
`Clopidogrel Drug that inhibits platelet
`function, now used instead of warFarin
`(luring stent placement.
`
`Hypertensitm High blood pressure.
`
`Invasive treatment Used in this report to
`refer to PCI or CABG.
`
`Ischaemia Lack of blood flow or oxygen.
`
`Lumen The space wi thin a blood vessel.
`
`MEDLINE A database of medical journal
`articles.
`
`Meta-analysis Method ofcomhining
`results from diilierent studies to produce
`a summary statistic.
`
`Minimally invasive CABG CABS technique
`using a small thoracotomy only and not
`always requiring Stopping of the heart during
`the operation.
`
`Myocardium Heart muscle.
`
`Myocardial infarction Death ol'a segment
`ol'heart muscle because of severe ischaemia.
`
`Creatinine kinase A cardiac enzyme, the
`Ostial lesion Lesion ol' the ostium of
`blood levels of which are raised during
`coronary artery {which is difficult to stent}.mntimmf
`myocardial infarction.
`
`
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`Glossary and list of abbreviations
`
`
`
`Glossary contd
`Platelets Blood constituents involved in
`blood clot formation.
`
`Provisional stenting Stem placement
`depending on suboptimal result of PTCA.
`
`Q wave An abnormal “rave on ECG
`indicating past myocardial infarction.
`
`Reocclusion Repeat complete blockage of
`coronary artery.
`
`Restenosis Re—narrowing of coronary artery.
`
`Revascularisafion Mainmining or improving
`coronary artery blood supply.
`
`during stent placement.
`
`Silent ischaemia lscl'laeinia of heart muscle
`
`found with exercise stress test where patient
`has no angina symptoms.
`
`Stent Small prosthesis inserted into coronary
`artery to keep the lumen open.
`
`Subacute ischaemie heart disease All
`manifestations of ischaemic heart disease
`
`except acute myocardial infarction.
`
`Thrombus Blood clot.
`
`Ticlopidine Drug that inhibits platelet
`function, now used instead of warfarin
`
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`Health TechnologyAssessment 2000; Vol. 4: No. 23
`
`
`
`List of abbreviations
`AMI
`
`acute myocardial infarction
`(see myocardial infarction)
`British Cardiovascular
`
`Intervention Society
`
`coronary artery bypass
`graft (ing)
`
`coronary artery disease
`
`cost—ell'ectiveness analysisa
`confidence interval (95%)
`creatine kinase
`
`chronic coronary occlusion
`
`cost per event-free survivor
`_
`_
`)F
`cost—utility study
`cerebi‘ovascular accident
`3
`(stroke)
`Database of Abstracts of
`Reviews of Ell'ectiveness
`
`Development and
`Evaluation Committee
`
`Dutch Guilder
`
`BClS
`
`CABG
`
`(LAD
`
`(IEA
`
`CI
`
`CK—MB
`
`(30
`
`cost/ EFS
`CU
`
`(IVA
`
`DARE
`
`DEC
`
`DFI
`
`eCABG
`
`EFS
`
`EUROQOL
`
`1H1)
`
`INR
`
`LAD artery
`
`LMW heparins
`
`LoS
`LVEF
`
`MACCE
`
`MACE
`
`Ml
`
`MID
`
`MVD
`
`N/A
`
`N /C
`NR
`
`NS
`
`NHSEED
`
`i
`
`NICE.
`
`NSF
`
`OR
`
`PCI
`
`PMI
`
`PTCA
`
`PYAR
`
`QALY
`
`QOL
`Rcr
`
`SA
`
`SD
`
`SF—36
`
`SMR
`
`SVD
`
`emergency CABCS
`event—tree suivival or survivor
`standardised assessment
`
`method for quality of
`
`
`life (used in cost—. u . 8
`
`
`utility studies)
`ischaemic heart disease
`
`International
`Normalised Ratio$
`
`left anterior descending
`coronary artery
`
`lo“.r molecular weight
`heparins (used for blood
`anticoagulation)it
`
`length of stay
`
`TIMI [low grade
`
`left ventricular ejection
`fraction (measure of
`heart performance)
`
`major adverse coronary and
`cerebi‘ovascular events
`major adverse 3
`coronary CVCIIIS
`
`TLR
`
`TVR
`
`UA
`
`YLI.
`
`minimal lumen diameter
`
`of coronary artery
`.
`.
`multi—vessel coronary disease
`_
`s
`not applicable
`*
`not clear
`
`*
`
`not recorded;
`_
`_
`_
`_
`not statistically Significant
`NHS Economic
`Evaluations Database
`
`is
`
`National Institute for
`Clinical Excellence
`
`National Service Framework
`
`odds ratio
`
`percutaneous coronary
`intervention (includes PTCA,
`atherectomy, excimer laser,
`rotablator, stems)
`
`.
`t
`_
`Bil
`previous myocardial
`intarction
`
`percutaneous transluminal
`coronary angioplasty
`
`person years at risk
`
`quality adjusted life-year
`
`quality of life?
`randomised controlled trial
`
`stable angina?
`standard deviationat
`Short Form 36
`
`standardised mortality ratio
`
`_
`1‘
`single vessel coronary
`disease
`
`Thrombolysis In Myocardial
`Infarction flow grade
`[0 (poor) — 4 (good)]*
`
`target lesion
`revascularisation
`
`target vessel revascularisation
`'
`*
`unstable angina
`
`years of life lost
`
`myocardial infarction
`(heart attack)
`3 Used only in tables
`
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`Health TechnologyAssessment 2000; Vol. 4: No. 23
`
`Executive
`
`summary
`
`Background
`
`Methods
`
`Coronary artery stems are prosthetic linings
`inserted into coronary arteries via a catheter
`to widen the artery and increase blood flow to
`ischaemic heart muscle. They are used in the
`treatment of iscliaelnic heart disease (II-ID).
`
`IHD is a major cause of morbidity and mortality
`(123,000 deaths per annum) in the UK and a
`major cost to the NHS. Clinical effects of IHD
`include subacute manifestations (stable and
`unstable angina) and acute manifestations
`(particularly myocardial infarction [MI]).
`Treatment includes attention to risk factors,
`drug therapy, percutaneous invasive interventions
`(PCIs) (including percutaneous transluminal
`coronary angioplasty [PTCA] and stents) and
`coronary artery bypass graft surgery (CABS).
`
`In the last decade there has been a steady and
`significant increase in the rate of PCIs for IHD.
`In the UK. rates per million population increased
`from 174 in 1991 to 437 in 1998. Stents are now
`used in about 70% of I’Cls. Data from the rest of
`Europe suggest there is potential for PC] and stent
`rates to increase considerably. In the UK there is
`evidence of under-provision and inequity of
`access to revascularisation procedures.
`
`Objectives
`
`The following questions were addressed.
`
`I. What are the effects and effectiveness of elective
`stent insertion versus PTCA in subacute II-ID,
`particularly stable angina and unstable angina?
`2. What are the effects and elfectiveness of elective
`stem. insertion versus CABG in subacute IHD,
`particularly stable angina and unstable angina?
`3. What are the effects and effectiveness of elective
`stent insertion versus PTCA in acute MI (AMI)?
`4. What are best estimates of UK cost for elective
`stent insertion, PTCA and CABS in the
`circumstances of review questions 1 to 3?
`5. What are best estimates of cost-effectiveness and
`
`cost—utility for elective stent insertion relative to
`PTCA or (JABG in the circumstances of review
`
`questions 1 to 3?
`
`A systematic review addressing the objectives
`was undertaken.
`
`Data sources
`
`A search was made for RCTs comparing stems
`(inserted during a PTCA procedure} with PTCA
`alone or with CABG in any manifestation of IHD.
`The search strategy covered the period from 1990 to
`November 1999 and included searches of electronic
`databases {MEDLINE EMBASE. BIDS 181. The
`Cochrane Library), Internet sites, and handsearches
`of cardiology conference abstracts and 1999 issues
`ofcardiologyjournals. Lead researchers and local
`clinical experts were contacted. Manufiicturers' sub—
`missions to the National Institute for Clinical
`Excellence were searched.
`
`The search strategy was expanded to look for
`relevant economic analyses and information to
`inform the economic model (including searching
`MEDLINE, the NHS Economic Evaluation Data
`base and the Database of Abstracts of Reviews of
`Effectiveness). Searches focused on research that
`reported costs and quality oflife data associated
`with [HD and interventional cardiology.
`
`Study selection
`For the review ofclinical effectiveness, inclusion
`criteria were: (i) RCT design; (ii) study population
`comprising adults with IHD in native or graft
`vessels (including patients with subacute [HD or
`AMI); (iii) procedure involving elective insertion
`of coronary artery stents; (iv) elective PTCA {in—
`cluding PTCA with provisional stenting) or CABG
`as comparator; (v) outcomes defined as one or
`more of: combined event rate (or event—free sur—
`vival), death, Ml, angina. target vessel revascular—
`isation, CABG, repeat PTCA. angiographic
`outcomes; (vi) trials that had closed and reported
`results for all or almost all recruited patients.
`
`For the economic evaluation, studies of adults with
`1H1) were included if they were of the following
`types: studies reporting UK costs; comparative
`economic evaluation combining both costs and
`outcomes; economic evaluations reporting costs
`and outcomes separately for the years 1998 and
`1999 {to ensure current practice was included).
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`Executive summary
`
`Data extraction
`For the review of clinical effectiveness, data were
`extracted into data extraction forms and RCT
`
`quality was assessed using standard methods.
`Decisions relating to data extraction and quality
`were made by two independent reviewers. Dis-
`agreements were resolved by discussion and with
`the aid ofa third party if there was any residual
`discrepancy. The quality assessment of cost
`effectiveness analyses was based on a pre—
`determined check-list.
`
`Data synthesis
`For the review of clinical elfecLiveness, abstracted
`data were collated in summary tables. Wienever
`possible, analysis was on an intention—to—treat basis.
`Mela-analyses were carried out when adequate
`data were available.
`
`Costs and economic analyses
`The information identified contributes only to
`conclusions concerning elective stent insertion
`compared with PTCA in subacute IHD. There
`was wide variation in the estimates of cost, cost-
`effectiveness and cost—utility. Cost estimation,
`particularly for wider costs, was generally poor.
`It was probably conducted best in the context of
`the costiell'ectiveness studies. These generally
`showed that cost/event—free survivor for elective
`stenting was equivalent to or less than that of
`FTCA. They support the view that higher initial
`costs of stents are outweighed by savings from
`reduced requirement for repeat PTCA. The
`majority of cost—utility studies reported cost/
`QALY estimations in the range of £20,000—
`£30,000. Reasons why these estimates should
`be treated with caution were identified.
`
`For the economic evaluation, cost data and
`health economic assessments were documented
`and evaluated.
`
`The efficiency of the use of stents compared with
`CABG in subacute IHD or stems compared with
`PTCA in AMI is unknown.
`
`Results
`
`Conclusions
`
`Effects and effectiveness
`
`Thirty-five RCTs which fulfilled the study criteria
`were found: 25 compared stent with P’TCA for
`subacute [HD; three compared stems with (JABG
`for subacute IHD; seven compared stents with
`PTCA following AM]. In general, the trials were
`open to bias, which introduced uncertainty.
`Despite this, convincing evidence of impact
`was identified in the following.
`
`1. Elective stent insertion versus PTCA in subacute
`IHD for:
`
`' event rates (generally death, MI, repeat FTCA
`and (JABG) 7 odds ratio (OR), 0.68 (95%
`confidence interval [CI]. 0.59 to 0.78)
`repeat PTCA — OR, 0.57 (95% CI, 0.48
`to 0.69)
`2. Elective stent insertion versus PTCA in
`AMI for:
`
`I
`
`' event rates (generally death, Ml, repeat
`PTCA and CAB-G) — OR, 0.39 (95% Cl.
`0.28 to 0.54)
`repeat PTCA 7 OR. 0.44 (95% (31,026
`to 0.74).
`
`-
`
`There was no clear evidence of impact on deaths,
`M1 or (LABG in comparison (1) or (2} above.
`Although trials were identified. there was insuffi-
`cient evidence to draw any conclusions on the
`effectiveness of elective stent insertion versus
`(JABG in subacute IHD.
`
`In subacute IHD (especially stable angina and
`unstable angina), there is evidence for the effec-
`tiveness of elective stents in reducing the need
`for repeat PTCA. This appears to represent an
`efficient use of resources. However, this assertion
`could be made with more confidence if the
`
`resource neutrality of stents could be confirmed
`using more rigorously derived cost data. There
`is currently insufficient evidence to assess the
`effectiveness of the extension of stent use to
`
`patients with baseline risks or indications different
`from those of the patients in the trials reviewed
`(for review question 1).
`
`Recommendations for further
`evaluation and research
`1. For many important stenting applications.
`research is ongoing and a reassessment of
`research evidence and health economic evalu—
`
`ations in 1—2 years' time would be valuable.
`2. Further research on the use of stents is needed
`
`to: acquire better cost data, using explicit
`microcosting; investigate the impact of
`stems on severity of angina and quality
`of life; evaluate the effectiveness of
`newer technologies.
`3. It is very important to establish clearly the
`effectiveness and efficiency of stents compared
`with CABG, and even though there is
`considerable ongoing research in this area.
`further targeted research may be valuable.
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`Health TechnologyAssessment 2000; Vol. 4: No. 23
`
`Chapter I
`
`Review aims and background
`
`Aims
`
`0 To assess the ellectiveness of coronary artery
`stents compared with other established
`revascularisation procedures (percutaneous
`transluminal coronary angioplasty [PTCA]
`alone and coronary a1 lery bypass glaftiug
`[CABGD in the main manifestations of
`ischaemic heart disease (IHD).
`' To assess the costs, cost-efi'ectiveness and
`cost—utility of the above.
`
`Introduction
`
`A coronary artery stent is a metal tube, coil or
`mesh that is inserted into a cm‘onary artery, via a
`catheter inserted in art artery in the groin or arm,
`in order to widen the coronary artely and improve
`the blood flow to ischaemic heart muscle.
`
`lnterventional cardiologists are increasingly using
`coronary artery stems to treat IHD.l The procedure
`is carried out in a cardiac catheterisation lab—
`
`oratory. The stents can be inserted as an elective
`procedure (elective stenting), or alter a FTCA
`with sub—optimal results (‘provisional stenting')
`or where there is an acute closure of the artery
`after PTCA (emergency or ‘hailoul' stenting).
`
`Description of health problem
`
`Disease
`IHD is caused by an instillicient supply of oxygen
`to the heart muscle. It can be ‘silent‘ (when the
`patient has no symptoms) or can cause angina,
`unstable angina, myocardial infarction (MI)
`or death.
`
`In this report we distinguish between acute
`myocardial infarction (AMI) and the subacute
`manifestations of IHD, particularly angina and
`unstable angina.
`
`Pathology
`FBI) is generally caused by constriction or blockage
`of the coronary arteries supplying the heart. This is
`also known as coronary artery disease (CAD). The
`vast majority of IHD is due to atheroma and its
`
`complications. All-lemma occurs when there is
`damage to the linings ofarteries leading to the
`formation of raised patches oflibrous and fatty
`material, known as atheromatous plaques.
`
`Epidemiology
`IHD is the major cause ofdealh of men and
`women in the UK.2 In 1997 there were 122,780
`deaths due to IHD in the UK {22% of all deaths
`and 25% of deaths in men}.3
`
`Although deaths from IHD have fallen over by
`over two—thirds in the last 30 years, UK rates remain
`higher than in many countries (e.g. the death rate
`in the UK is over three times that of France. the
`EU country with the lowest death rate).‘ When
`measured in terms of years of life lost (YI.I.), IHD
`accounts for 15.6% of all years of life lost (1,365,995
`YLL per year). The figure is 19.3% for mend|
`
`It is estimated that, in Europe, IHD is the leading
`single cause of disability accounting for 9.7% of
`total disability adjusted lil'eyearsf’ Given the high
`incidence of IHD in England and Wales, the
`figure will be even higher here.
`
`The results of the 1998 Health Survey for England6
`indicate an overall prevalence of IHD of 7.1% in
`men and 4.6% in women. Prevalence increases
`
`markedly with age, reaching 23.4% in men and
`18.4% in women aged over 75 years. The point
`prevalence of angina is estimated to be 3.2%
`for men and 2.5% for women; 5.3% of men and
`3.9% ofwomen reported ever having had angina.
`Overall 4.2% of men and 1.8% oi'women reported
`having had a heart attack (0.6% of men and
`0.3% of women reported having it Within the
`last 12 months).Ii
`
`The Fourth General Practice Morbidity Survey
`(1991—1992)7 gives the prevalence and incidence
`rates per 10,000 person years at risk (PYAR) for
`AMI and angina pectoris“ (Treble I ). Comparison
`of the Fourth Survey with the Third General
`Practice Morbidity Survey (1981 ) suggests that
`the rates for angina are rising.‘
`
`Aetiology
`Cigarette smoking and other tobacco use are
`associated with an increase in atheroma and
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`Review aims and background
`
`TABLE I Prevalence and incidence rates ofAMl and angina per
`l0,000 person years at risk (PYARV
`
`revascularisation (PTCA and CABS), which are
`increasingly being replaced by stenting.
`
`Prevalence
`
`Incidence
`
`Men Women
`
`Men Women
`
`AMI
`
`Angina
`
`38
`
`| 30
`
`20
`
`98
`
`29
`
`55
`
`| 6
`
`49
`
`are a major risk factor for IHD. Diabetes mellitus,
`hypertension. raised cholesterol. genetic pre-
`disposition, diet, lack of exercise and obesity
`are also risk factois.
`
`Many of these risk factors can be modified
`and IHD has been identified as a major con-
`tributor to avoidable mortality. Reduction in
`circulatory disease mortality is a major UK
`government target in the strategy to improve
`the nation 's health.‘J
`
`Treatments of established IHD
`introduction
`
`Although preventing IHD is important, this
`paper is concerned with the treatments that aitn
`to reduce both the morbidity and the mortality
`in patients with established IHD. Treatment of
`IHD has many modalities:
`
`' modification of tisk factors
`
`' medical management
`' percutaneous invasive treatments (carried out
`by interventional cardiologists)
`0 surgical interventions.
`
`Medical treatments have many mechanisms of
`action and rationales. They may aim to:
`
`reduce risk factors causing IHD
`-
`reduce the physical demand on the heart
`I
`improve the blood flow within the heart
`I
`' alter the clotting characteristics of blood.
`
`There are now many well established treatments for
`both [HD and many of its risk factors. Many clearly
`contribute to both alleviation of symptoms and
`prevention of adverse events, such as AM] and
`death. The aims of treatment are to prolong life,
`prevent Ml. prevent damage to the heart and heart
`failure, relieve painful and disabling angina and
`other wmptoms. and improve quality of life.
`
`This paper does not review the evidence for all
`of these treatments or discuss their relative merits,
`but concentrates on coronaiy artery stenting
`and the alternative established methods of
`
`It is useful to have a brief overview of revascular—
`
`isation techniques over the last 30 years in order
`to understand why stents were developed. Initially,
`revascularisation began in order to provide altern—
`ative therapy when medical treatments failed to
`control symptoms. The basic aim of all revasculare
`isation procedures is to provide a better lumen in
`the vessel supplying heart muscle to improve
`blood flow.
`
`CABG
`
`CABG is a surgical technique that involves opening
`the chest wall and bypassing a blocked or narrowed
`section of a coronary artery, usually by using a vein
`or artery taken from elsewhere in the patient’s body.
`
`CABGS began in the late 19605. They are carried
`out by cardiothorac