CARDIOVASCULAR DISEASES

Health Evidence Bulletins - Wales (logo)
Team Leader: Dr David Fone

Date of completion: 30.9.98

2: Stable angina

This bulletin is a supplement to, not a substitute for, professional skills and experience. Users are advised to consult the supporting evidence for a consideration of all the implications of a recommendation.

The Statements The Evidence
2.1 Clinical guidelines
2.1a. Stable angina is characterised by exertional chest pain relieved by rest, resulting from the partial obstruction of a coronary artery by atheroma. Angina is more common in men and with increasing age. Overall it is estimated that over a one year period around 1% of the population present with symptoms of angina to their GP and of these around 10% will subsequently have a non-fatal or fatal myocardial infarctioni. Clinical guidelines and audit standards for the investigation and management of stable angina are available from the British Cardiac Society and Royal College of Physiciansii, and the European Society of Cardiologyiii.
(Health gain notation - 1 "beneficial")
i. Management of Stable Angina. Effective Health Care. Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997
http://www.york.ac.uk/inst/crd/ehc35.htm
(Type II evidence - review of randomised controlled trials)
ii. de Bono DP, Hopkins A, for a working party of the joint audit committee of the British Cardiac Society and the Royal College of Physicians of London. The investigation and management of stable angina. British Cardiac Society, 1996.
http://www.cardiac.org.uk/
(Type V evidence - expert opinion)
iii. Julian DG, Bertrand ME, Hjalmarsson A, et al. Management of stable angina pectoris. European Heart Journal 1997;18:394-413
http://www.escardio.org/scinfo/guidelines/
97management.pdf

[Adobe Acrobat reader required]
(Type V evidence - expert opinion)
2.2 ECG and exercise testing
2.2a. A 12 lead electrocardiograph (ECG) is a routine investigation for patients with suspected angina. A normal ECG does not exclude coronary artery disease; an abnormal ECG supports the clinical diagnosis and identifies patients with poorer prognosisi,ii.
(Health gain notation - 2 "likely to be beneficial")
i. Norell M, Lythall D, Cochlan G, et al. Limited value of the resting electrocardiogram in assessing patients with recent onset chest pain: lessons from a chest pain clinic. British Heart Journal 1992;67:53-56
(Type IV evidence - case series of 250 patients referred with recent onset chest pain)
ii. Mirvis DM, El-Zeky F, Vander Zwaag R, et al. Clinical and pathophysiologic correlates of ST-T wave abnormalities in coronary artery disease. American Journal of Cardiology 1990;66:699-704
(Type IV evidence - cross-sectional analysis of clinical, ECG, haemodynamic and angiographic data from 9801 patients)

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2.2b. Exercise ECG is a low risk investigation (overall cardiac complication rate 0.8/10,000 tests, 95% CI: 0.3, 1.9)i and is effective in assessing prognosis in patients with coronary artery disease and identifying patients who would benefit from further investigationii,iii.
(Health gain notation - 2 "likely to be beneficial")

 

i. Gibbons L, Blair SN, Kohl HW, Cooper K. The safety of maximal exercise testing. Circulation 1980;80:846-52
(Type IV evidence - case review of 71,914 maximal exercise tests conducted between 1971 and 1987)
ii. Mark DB, Hlatky MA, Harrell FE Jr, Lee KL, Califf RM, Pryor DB. Exercise treadmill score for predicting prognosis in coronary artery disease. Annals of Internal Medicine 1987;106:793-800
(Type IV evidence - case series of 2842 patients referred for exercise testing and cardiac catheterisation with a median follow-up of 10 years)
iii. Weiner DA, Ryan TJ, McCabe CH, et al. Prognostic importance of a clinical profile and exercise test in medically treated patients with coronary artery disease. Journal of the American College of Cardiology 1984;3(3):772-79
(Type IV evidence - prospective cohort study of 4083 patients referred for cardiac catheterisation from the CASS clinical trial registry followed-up for three years)
2.2c. Exercise ECG is of limited usefulness in the diagnosis of patients with a low pre-test probability of coronary heart disease

(CHD)i-iv, particularly in womeniii,iv in whom the specificity and positive predictive value of exercise ECG are significantly lower than in men (71% vs. 93%, p<0.001 and 76% vs. 95%, p<0.001, respectively)iii.
(Health gain notation - 5 "unlikely to be beneficial")

 

i. Diamond GA, Forrester JS. Analysis of probability as an aid in the clinical diagnosis of coronary artery disease. New England Journal of Medicine 1979;300:1350-58
(Type IV evidence - Bayesian analysis based on data from observational studies and post-mortem case series)
ii. Weiner DA, Ryan TJ, McCabe CH, et al. Exercise stress testing. Correlations among history of angina, ST-segment response and prevalence of coronary artery disease in the coronary artery surgery study (CASS). New England Journal of Medicine 1979;301:230-35
(Type IV evidence - correlation of exercise test data with angiography in 2045 symptomatic patients from the CASS clinical trial registry)
iii. Sullivan AK, Holdright DR, Wright CA, Sparrow JL, Cunningham D, Fox KM. Chest pain in women: clinical, investigative, and prognostic features. British Medical Journal 1994;308:883-86
http://www.bmj.com/cgi/content/full/308/6933/883

(Type IV evidence - comparison of exercise test data with angiography in 202 women and 684 men referred with chest pain)
iv. Holdright DR, Fox KM. Characterisation and identification of women with angina pectoris. European Heart Journal 1996;17:510-17
(Type IV evidence - summary review of clinical studies and case series)

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2.2d. Evidence-based guidelines for exercise testing are availablei.
(Health gain notation - 1 "beneficial")

 

i. Gibbons RJ, Balady GJ, Beasley JW, et al. ACC/AHA guidelines for exercise testing: a report of the American College of Cardiology/American Heart Association task force on practice guidelines (committee on exercise testing). Circulation 1997;96:345-54
(Type V evidence - expert opinion)
2.3 Myocardial perfusion imaging
2.3a. Radionucleide myocardial perfusion imaging with thallium-201 or technetium-99 based perfusion agents is a valuable adjunct to exercise ECG as a non-invasive method of assessment of patientsi,ii, particularly in patients unable to exercise.
(Health gain notation - 1 "beneficial")
i. Mayo Clinic Cardiovascular Working Group on Stress Testing. Cardiovascular stress testing: a description of the various types of stress tests and indications for their use. Mayo Clinic Proceedings 1996;71:43-52
(Type IV evidence - summary review of clinical studies and case series)
ii. Brown KA. Prognostic value of cardiac imaging in patients with known or suspected coronary artery disease: comparison of myocardial perfusion imaging, stress electrocardiography, and positron emission tomography. American Journal of Cardiology 1995;75:35-41
(Type IV evidence - summary review of observational clinical studies and case series)
2.3b. Evidence-based guidelines for the use of cardiac radionucleide imaging are availablei.
(Health gain notation - 1 "beneficial")

 

i. Ritchie JL, Bateman TM, Bonow RO, et al. ACC/AHA guidelines for clinical use of cardiac radionucleide imaging: a report of the American Heart Association/American College of Cardiology task force on assessment of diagnostic and therapeutic cardiovascular procedures, committee on radionucleide imaging, developed in collaboration with the American Society of Nuclear Cardiology. Circulation 1995;91:1278-303
(Type V evidence - expert opinion)
2.4 Drug therapy
2.4a. There is no randomised controlled trial evidence for major differences between the main classes of drug treatment (beta-blockers, nitrates and calcium channel blockers) in the effectiveness of relief of symptomatic angina, or that combination therapy is more effective than monotherapyi.
(Health gain notation - 1 "beneficial")
i. Management of Stable Angina. Effective Health Care Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997
http://www.york.ac.uk/inst/crd/ehc35.htm
(Type II evidence - review of randomised controlled trials)

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2.4b. There is evidence to suggest that bisoprolol is more effective than nifedipine for complete cessation of transient asymptomatic ischaemic episodesi (number needed to treat NNT=3; 95% CI: 2, 4), for 20mg daily bisoprolol compared to 40mg twice daily slow release nifedipine) and more effective than isosorbide dinitrate for cessation of exercise induced angina (NNT 5.0; 95% CI: 2.8, 21.0) for 20mg daily bisoprolol compared to 20mg isosorbide dinitrate three times a dayii. Benefits were sustained at one year follow-upiii.
(Health gain notation - 2 "likely to be beneficial")
i. von Arnim T, for the TIBBS Investigators. Medical treatment to reduce total ischaemic burden bisoprolol study (TIBBS), a multicentre trial comparing bisoprolol and nifedipine. Journal of the American College of Cardiology 1995;25:231-38
(Type II evidence - review of randomised controlled trial of 330 patients with stable angina, positive exercise test and transient ischaemia during Holter monitoring and eight week follow-up)
ii. Angina. Bandolier 1997, Number 40. Volume 4 Issue 6
http://www.jr2.ox.ac.uk/bandolier/band40/b40-3.html
(Type II evidence - NNT calculations using data from reference (i) and review of randomised controlled trials)
iii. von Arnim T, for the TIBBS Investigators. Prognostic significance of transient ischaemic episodes: response to treatment shows improved prognosis. Journal of the American College of Cardiology 1996;28:20-24
(Type II evidence - review of randomised controlled trial of 330 patients with stable angina, positive exercise test and transient ischaemia during Holter monitoring and one year follow-up)
2.5 Secondary prevention
2.5a. Antiplatelet therapy in patients with stable angina reduces myocardial infarction (MI), stroke or vascular death (odds reduction 33%, SD 9%, p<0.0005). Most patients in the trials received aspirin - where comparison between regimens and antiplatelet agents were possible no significant differences were notedi.
(Health gain notation - 1 "beneficial")
i. Antiplatelet Trialist's Collaboration. Collaborative overview of randomised trials of antiplatelet therapy - I: Prevention of death, myocardial infarction and stroke by prolonged antiplatelet therapy in various categories of patients. British Medical Journal 1994;308:81-106.
http://www.bmj.com/cgi/content/full/308/6943/1540
In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 4. Oxford: Update Software, 1998
(Type I evidence - systematic review and sub-group meta-analysis of 3000 patients with stable angina in seven trials of antiplatelet therapy)
2.5b. Smoking increases the risk of death (relative risk 1.76; 95% CI: 1.37, 2.26) and MI (relative risk 2.08; 95% CI: 1.16, 3.72) following PTCA i.
(Health gain notation - 6 "harmful")
i. Hasdai D, Garratt KN, Grill DE, Lerman A, Holmes DR Jr. Effect of smoking status on the long-yerm outcome after successful percutaneous coronary revascularisation. New England Journal of Medicine 1997;336:755-61
(Type IV evidence - prospective cohort study of 5450 patients (mean age 64 years, 74% men) with 16 year follow-up)
2.5c. Smoking cessation reduces mortality in patients with CHD with no diminution of effect with increasing age. The excess risks of coronary artery death, MI and atherosclerosis return to non-smoking levels within 10-20 yearsi,ii.
(Health gain notation - 1 "beneficial")

 

i. Omenn GS, Anderson KW, Kronmal RA, Vlietstra RE. The temporal pattern of reduction of mortality risk after smoking cessation. American Journal of Preventive Medicine 1990;6:251-57
(Type IV evidence - prospective cohort study of 21,112 men and women in the Coronary Artery Surgery Study (CASS))
ii. Doll R, Peto R. Mortality in relation to smoking: 20 years’ observation on male British doctors. British Medical Journal 1976;2:1525-36
(Type IV evidence - prospective cohort study of 34,440 male British doctors with 20 year follow-up)

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2.6 Coronary revascularisation
2.6a. Coronary Artery Bypass Grafting (CABG) is more effective at relieving symptoms of angina and improving quality of life indicators over five years than medical therapy, with less advantage by ten years follow-upi.
(Health gain notation - 2 "likely to be beneficial")
i. Rogers WJ, Coggin, CJ, Gersh BJ, et al. Ten year follow-up of quality of life in patients randomised to receive medical therapy or coronary artery bypass graft surgery. Circulation 1990;82:1647-58
(Type II evidence - randomised controlled trial of 780 patients with ten year follow-up)
2.6b. CABG reduces total mortality at ten year follow-up compared to medical treatment (odds ratio 0.83; 95% CI: 0.70, 0.98). Survival benefit of CABG at ten years increases with severity of coronary artery disease: left main artery disease 19 months; 3 vessel disease 6 months; 1 or 2 vessel disease 2 months (p=0.02 for trend)i.
(Health gain notation - 1 "beneficial")

Caveat: Inclusion criteria and assessment of validity of primary studies not stated.

i. Yusuf S, Zucker D, Peduzzi P, et al. Effect of coronary artery bypass graft surgery on survival: overview of 10 year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration. Lancet 1994;344:563-70. In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 4. Oxford: Update Software, 1998
(Type I evidence - systematic review and meta-analysis of 2649 patients with stable angina or previous MI in seven trials)
2.6c. Percutaneous Transluminal Coronary Angioplasty (PTCA) is more effective in relieving symptoms of angina than medical treatment i,ii (64% vs. 46% angina free at six-month follow-up, p<0.01)i; the advantages are greatest in patients with more severe anginaii and single vessel diseaseiii. PTCA has not been shown to improve survivalii; death or non-fatal MI was significantly more frequent with PTCA at median 2.7 years follow-up (6.3% vs. 3.3%, absolute risk difference 3%; 95% CI: 0.4%, 5.7%; p=0.02), but not deaths alone (2% vs. 1%, p=0.32)ii. At three year follow-up PTCA confers little benefit over medical treatment due to high rate of stenosisii,iii.
(Health gain notation - 3 "trade-off between beneficial and adverse effects")

Caveat: Further trials comparing PTCA vs. medical therapy in patients with double vessel disease are required.

i. Parisi AF, Folland ED, Hartigan P. A comparison of angioplasty with medical therapy in the treatment of single-vessel coronary artery disease. Veterans Affairs, ACME Investigators. New England Journal of Medicine 1992;326:10-16
(Type II evidence - randomised controlled trial of 212 patients with significant stenosis in at least one coronary artery randomised to PTCA or medical therapy)
ii. RITA-2 trial participants. Coronary angioplasty versus medical therapy for angina: the second Randomised Intervention Treatment of Angina (RITA-2) trial. Lancet 1997;350:461-68
(Type II evidence - randomised controlled trial of 1018 patients with stable angina, unstable angina or previous MI and significant stenosis in at least one coronary artery randomised to PTCA or medical therapy)
iii. Folland ED, Hartigan PM, Parisi AF. Percutaneous transluminal coronary angioplasty versus medical therapy for stable angina pectoris: outcomes for patients with double-vessel versus single-vessel coronary artery disease in a Veterans Affairs Cooperative randomised trial. Veterans Affairs ACME Investigators. Journal of the American College of Cardiology 1997;29:1505-11
(Type II evidence - randomised controlled pilot trial of 328 male patients with single or double vessel disease and stable angina randomised to PTCA or medical therapy)

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2.6d. CABG is more effective at relieving symptoms of angina than PTCA at three year follow-up (odds ratio 1.47; 95% CI: 1.32, 1.87; p<0.000) with no difference in mortality (3.7% vs. 3.9%) or combined risk of death or non-fatal MI (10.1% vs. 9.8%). CABG patients were less likely to undergo either a subsequent CABG (1% vs. 19.7%, odds ratio 0.04; 95% CI: 0.02, 0.07; p<0.000) or subsequent PTCA (6% vs. 22.9%, odds ratio 0.21; 95% CI: 0.16, 0.27; p<0.000)i.
(Health gain notation - 1 "beneficial")

Caveat: Stringent entry criteria may limit generalisability to the wider population of patients requiring revascularisation.

i. Sim I, Gupta M, McDonald K, Bourassa MG, Hlatky MA. A meta-analysis of randomised trials comparing coronary artery bypass grafting with percutaneous transluminal coronary angioplasty in multivessel coronary artery disease. American Journal of Cardiology 1995;76:1025-29. In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 4. Oxford: Update Software, 1998
(Type I evidence - systematic review and meta-analysis of 2943 patients in five randomised controlled trials)

 

2.6e. No recent cost-effectiveness analyses comparing either CABG or PTCA to medical therapy are available. Further research in this area is recommendedi.
(Health gain notation - 4 "unknown")
i. Management of Stable Angina. Effective Health Care. Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997
http://www.york.ac.uk/inst/crd/ehc35.htm
(Type I evidence - systematic literature search)
2.6f. Health service cost data from the RITA trial suggests the average initial cost of PTCA is around 52% of a CABG, but after two years this increases to 80% because of the need for subsequent interventions. Longer-term follow-up is required to assess relative cost-effectivenessi.
(Health gain notation - 4 "unknown")
i. Sculpher MJ, Seed P, Henderson RA, et al. Health service costs of coronary angioplasty and coronary artery bypass surgery: the randomised intervention treatment of angina (RITA) trial. Lancet 1994;344:927-30
(Type IV evidence - UK health service costs for 1993-94 applied to randomised controlled trial data)
2.6g. PTCA is appropriately used for palliation in patients with less severe disease, inadequately controlled on medical treatment. There is little evidence that this will improve survivali.
(Health gain notation - 3 "trade-off between beneficial and adverse effects")
i. Management of Stable Angina. Effective Health Care. Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997
http://www.york.ac.uk/inst/crd/ehc35.htm
(Type I evidence - systematic review)
2.6h. Antiplatelet therapy reduces re-occlusion rates in post-CABG patients compared to control (21% vs. 30%, benefit 90/1000 patients treated) and PTCA patients compared to control (4% vs. 8%, 40/1000 patients treated). The odds of reocclusion for CABG and PTCA combined was reduced at six-months by 41% (SD 6), p<0.0001i.
(Health gain notation -1 "beneficial")
i. Antiplatelet Trialists' Collaboration. Collaborative overview of randomised trials of antiplatelet therapy - II: Maintenance of vascular graft or arterial patency by antiplatelet therapy. British Medical Journal 1994;308:159-68.
http://www.bmj.com/cgi/content/full/308/6922/159
In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 4. Oxford: Update Software, 1998
(Type I evidence - systematic review and meta-analysis of 5323 patients in 20 CABG trials and 833 patients in three PTCA trials)

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2.6i. Lipid lowering therapy reduces progression of atherosclerosis, risk of non-fatal MI, stroke or cardiac death and need for revascularisation compared to placebo in post-CABG patientsi.
(Health gain notation - 1 "beneficial")

 

i. Azen SP, Mack WJ, Cashin-Hemphill L, et al. Progression of coronary artery disease predicts clinical coronary events. Long-term follow-up from the cholesterol lowering atherosclerosis study. Circulation 1996;93:34-41
(Type II evidence - randomised controlled trial of 162 non-smoking men aged 40-59 years with previous CABG randomised to colestipol/niacin plus diet or placebo plus diet followed-up for mean seven years)
2.6j. Calcium antagonistsi and fish oils (omega-3 fatty acids)ii may reduce restenosis rates following PTCA.
(Health gain notation - 4 "unknown")

Caveat: Variation in clinically meaningful outcomes in primary studiesi. Further evaluations in large randomised controlled trials which address clinical outcomes are necessary to assess the potential benefits.

 

i. Hillegass WB, Ohman EM, Leimberger JD, Califf RM. A meta-analysis of randomised trials of calcium antagonists to reduce restenosis after coronary angioplasty. American Journal of Cardiology 1994;73:835-39. In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 2. Oxford: Update Software, 1998
(Type I evidence - systematic review and meta-analysis of 919 patients in five trials)
ii. Gapinski JP, Van Ruiswyk JV, Heudebert GR, et al. Preventing restenosis with fish oils following coronary angioplasty. A meta-analysis. Archives of Internal Medicine 1993;153:1595-1601
(Type I evidence - systematic review and meta-analysis of 886 patients in seven trials)
2.6k. Antiplatelet therapy is likely to reduce the odds of MI, stroke or vascular death in post-PTCA and post-CABG patients by around 25% at six to twelve month follow-up. Review of different doses of aspirin in long-term treatment suggests equal efficacy of daily doses 75mg to 324mg per dayi.
(Health gain notation - 2 "likely to be beneficial")

Caveat: Based on a meta-analysis of antiplatelet therapy in 14 sub-categories of high risk patients, including post-PTCA and post-CABG patients, which showed an odds reduction of 27% (SD 2%) for MI, stroke or vascular death without significant heterogeneity.

i. Antiplatelet Trialist's Collaboration. Collaborative overview of randomised trials of antiplatelet therapy - I: Prevention of death, myocardial infarction and stroke by prolonged antiplatelet therapy in various categories of patients. British Medical Journal 1994;308:81-106.
http://www.bmj.com/cgi/content/full/308/6943/1540
In: Database of Reviews of Effectiveness. The Cochrane Library, Issue 4. Oxford: Update Software, 1998
(Type I evidence - systematic review and sub-group meta-analysis of 1332 patients in four trials of antiplatelet therapy in patients post-PTCA and 3075 in 19 trials post-CABG)

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2.6l. There is increasingly valid evidence that PTCA with elective stenting is more effective than standard angioplasty in reducing the need for subsequent revascularisation, or in reducing angina, stroke, MI or mortality at up to one year follow-upi,ii. Event-free survival (death, MI or revascularisation) at six months 12.8% vs. 19.3%, relative risk 0.67; 95% CI: 0.48, 0.92; p=0.013ii. There is no evidence that stents are cost-effective: the additional cost per quality adjusted life year is around 250,000i. Antiplatelet therapy reduces the incidence of cardiac events and haemorrhagic and vascular complications at 30 days post-stenting compared to anticoagulationiii. Stenting with abciximab glycoprotein IIb/IIIa blockade in addition to aspirin and ticlopidine reduces the 30 day incidence of death, MI or urgent revascularisation compared to stenting alone (10.8% vs. 5.3%, hazard ratio 0.48; 95% CI: 0.33, 0.69; p<0.001)iv.
(Health gain notation - 2 "likely to be beneficial")

Caveat: Methodological flaws including non-blinded outcome assessment or analysis not based on intention to treat and narrow inclusion criteria and operator skill dependence limits the validityv and generalisabilityi of the early published trials.

i. Chase D, Best L, Milne R. Development & Evaluation Committee Report (DEC) No. 87. Stents for Coronary Artery Disease. The Wessex Institute for Health Research & Development, 1998.
http://www.doh.gov.uk/research/swro/rd/publicat/dec/dec87.pdf
(Type I evidence - systematic review of five randomised controlled trials)
ii. Serruys PW, van Hout B, Bonnier H, et al, for the Benestent Study Group. Randomised comparison of implantation of heparin-coated stents with balloon angioplasty in selected patients with coronary artery disease (Benestent II). Lancet 1998;352:673-81
(Type II evidence - randomised controlled trial of 827 patients with stable or unstable angina)
iii. Schomig A, Neumann F, Kastrati A, et al. A randomised comparison of antiplatelet and anticoagulant therapy after the placement of coronary artery stents. New England Journal of Medicine 1997;334:1084-89
(Type II evidence - randomised controlled trial of 517 patients undergoing coronary artery stenting with mix of acute and chronic coronary syndromes)
iv. The EPISTENT Investigators. Randomised placebo-controlled and balloon-angioplasty-controlled trial to assess safety of coronary stenting with use of glycoprotein-IIb/IIIa blockade. Lancet 1998;352:87-92
(Type II evidence - randomised controlled trial of 2399 patients with stable or unstable angina)
v. Management of Stable Angina. Effective Health Care. Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997. http://www.york.ac.uk/inst/crd/ehc35.htm
(Type II evidence - summary review of randomised controlled trials)
2.6m. There is currently no evidence that laser angioplasty, and rotational coronary atherectomy are more effective than PTCAi. Directional coronary atherectomy (DCA) is associated with a lower six month restenosis rate than balloon angioplasty (31.4% vs. 39.8%, p=0.016), but with no difference in outcomes at one yearii. Catheter-based radiotherapy has been reported in one small trial to reduce restenosis at six months - further evaluation is requiredi.
(Health gain notation - 4 "unknown")

Caveat: DCA remains a rarely used technique. Further evaluation in trials to compare DCA with PTCA and stenting is required.

i. Management of Stable Angina. Effective Health Care. Volume 3 Number 5. University of York: NHS Centre for Reviews and Dissemination, 1997
http://www.york.ac.uk/inst/crd/ehc35.htm
(Type II evidence - summary review of randomised controlled trials)
ii. Baim DS, Cutlip DE, Sharma SK, et al for the BOAT Investigators. Final results of the balloon vs. optimal atherectomy trial. Circulation 1998;97:322-31
(Type II evidence - randomised controlled trial of 989 patients with single coronary lesions, 40% with previous MI)

 

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Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: weightmanal@cardiff.ac.uk