PATIENT VS PHYSICIAN REPORTED ANGINA BEFORE AND AFTER REVASCULARISATION OF CORONARY ARTERY DISEASE: EVIDENCE FROM A LARGE RANDOMISED CONTROLLED TRIAL (THE SOS TRIAL)

Authors' replySir—We agree with Sanjiv Sharma and colleagues that coronary-artery disease is a chronic disorder with a tendency for inexorable progression. In our routine clinical practice, the choice of initial revascularisation strategy is influenced by the patient's age and the potential for disease progression. At the Royal Brompton Hospital, patients with disease sparing the left anterior descending coronary artery were not considered for randomisation in the SoS trial, since an initial PCI strategy in this group allows for a subsequent first-time CABG if new disease develops in this vascular territory. Long-term follow-up data from the stent versus surgery trials could provide some insight into this important issue.S A M Nashef and colleagues request further insight into our interpretation of the mortality outcome measure. The apparent demonstration of survival advantage with surgery should be viewed with caution. The absolute number of deaths was low in both treatment groups, increasing the chances of a difference arising by chance; the disparity in the observed incidence of non-cardiac death illustrates this point. The study was not powered to examine for small differences in this secondary outcome measure. A new study, designed to confirm SoS cardiovascular mortality data (1·0% vs 2·2%) with a two-sided α of 0·05 and a power of 80% would need to recruit around 3500 patients.The external validity of the SoS trial has no greater worth than the findings of the ERACI II study, which report a high surgical mortality and survival advantage with percutaneous revascularisation.1Rodriguez A Bernardi V Navia J et al.Argentine Randomized Study: coronary angioplasty with stenting versus coronary artery bypass surgery in patients with multi-vessel disease (ERACI II): 30-day and one-year follow up results.J Am Coll Cardiol. 2001; 37: 51-58Summary Full Text Full Text PDF PubMed Scopus (311) Google Scholar Finally, we can find no evidence to support Nashef's assertion that patients with three-vessel disease and managed with CABG enjoy an established survival advantage over patients managed with PCI.Luke Devey and colleagues suggest that CABG is the more cost-effective therapy. This assertion is not supported by data from the ARTS2Serruys PW Unger F Sousa JE et al.Comparison of coronary-artery bypass surgery and stenting for the treatment of multivessel disease.N Engl J Med. 2001; 344: 1117-1124Crossref PubMed Scopus (1022) Google Scholar or SoS studies. The cost and cost-effectiveness analysis from the SoS trial has been reported at 2002 meetings of the British and European Cardiac Societies. The initial hospitalisation costs were higher in the CABG group than the PCI group (£7316 vs £3844, difference £3471[95% CI £3071–3880]). At 1 year, the cost difference narrowed but remained higher for CABG (£8900 vs £6257, difference £2643[£1814–3343]). The incremental cost-effectiveness ratio for CABG compared with PCI is £192474 per life-year gained (£77377–1085464), and £1719582 per quality-adjusted life-year (QALY) gained.Over a 1-year period, CABG is more expensive than PCI, and offers little added benefit in terms of QALYs. The additional initial cost of CABG could only be justified if there were continued and significant cost savings (compared with PCI) in subsequent years. Authors' reply Sir—We agree with Sanjiv Sharma and colleagues that coronary-artery disease is a chronic disorder with a tendency for inexorable progression. In our routine clinical practice, the choice of initial revascularisation strategy is influenced by the patient's age and the potential for disease progression. At the Royal Brompton Hospital, patients with disease sparing the left anterior descending coronary artery were not considered for randomisation in the SoS trial, since an initial PCI strategy in this group allows for a subsequent first-time CABG if new disease develops in this vascular territory. Long-term follow-up data from the stent versus surgery trials could provide some insight into this important issue. S A M Nashef and colleagues request further insight into our interpretation of the mortality outcome measure. The apparent demonstration of survival advantage with surgery should be viewed with caution. The absolute number of deaths was low in both treatment groups, increasing the chances of a difference arising by chance; the disparity in the observed incidence of non-cardiac death illustrates this point. The study was not powered to examine for small differences in this secondary outcome measure. A new study, designed to confirm SoS cardiovascular mortality data (1·0% vs 2·2%) with a two-sided α of 0·05 and a power of 80% would need to recruit around 3500 patients. The external validity of the SoS trial has no greater worth than the findings of the ERACI II study, which report a high surgical mortality and survival advantage with percutaneous revascularisation.1Rodriguez A Bernardi V Navia J et al.Argentine Randomized Study: coronary angioplasty with stenting versus coronary artery bypass surgery in patients with multi-vessel disease (ERACI II): 30-day and one-year follow up results.J Am Coll Cardiol. 2001; 37: 51-58Summary Full Text Full Text PDF PubMed Scopus (311) Google Scholar Finally, we can find no evidence to support Nashef's assertion that patients with three-vessel disease and managed with CABG enjoy an established survival advantage over patients managed with PCI. Luke Devey and colleagues suggest that CABG is the more cost-effective therapy. This assertion is not supported by data from the ARTS2Serruys PW Unger F Sousa JE et al.Comparison of coronary-artery bypass surgery and stenting for the treatment of multivessel disease.N Engl J Med. 2001; 344: 1117-1124Crossref PubMed Scopus (1022) Google Scholar or SoS studies. The cost and cost-effectiveness analysis from the SoS trial has been reported at 2002 meetings of the British and European Cardiac Societies. The initial hospitalisation costs were higher in the CABG group than the PCI group (£7316 vs £3844, difference £3471[95% CI £3071–3880]). At 1 year, the cost difference narrowed but remained higher for CABG (£8900 vs £6257, difference £2643[£1814–3343]). The incremental cost-effectiveness ratio for CABG compared with PCI is £192474 per life-year gained (£77377–1085464), and £1719582 per quality-adjusted life-year (QALY) gained. Over a 1-year period, CABG is more expensive than PCI, and offers little added benefit in terms of QALYs. The additional initial cost of CABG could only be justified if there were continued and significant cost savings (compared with PCI) in subsequent years.