Introduction The success of revascularisation therapies for coronary artery disease (CAD) must be measured by both an improvement in hard clinical endpoints—mortality, repeat revascularisation procedures and myocardial infarction, the traditional focus of clinical trials—and, critically for patients, the relief of angina symptoms. Interest in patient reported outcomes (PROMs) has increased, although their use in cardiovascular trials is far from universal. In particular the differences between physician and patient reported outcomes has not been analysed. High quality data from the Stent or Surgery (SOS) trial allows such an analysis.
Methods The SoS trial was a large RCT (n=988) comparing stent-assisted percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel CAD. Participation in the SoS trial included an appraisal of angina symptoms by both patient and physician according to the Canadian Cardiovascular Society (CCS) Classification System prior to, and subsequently at 6 and 12 months following coronary intervention. In this study patient and doctor reported outcomes were compared systematically.
Results Paired CCS scores at baseline, 6 months and 12 months were available for 919, 886 and 888 cases respectively. At baseline the overall level of agreement was good with >75% paired data sets demonstrating a difference of ≤±1 CCS class. Patterns of discordance change however between baseline and follow-up time points. Abstract 40 figure 1 shows the paired scores at baseline, charting the patient score and, for each CCS grade, the observed difference—doctor (D) minus patient (P). Doctors are reluctant to record scores of 0 or 4, preferring CCS grades 2 and 3. Thus there is little overall difference in mean CCS score (P 2.2 vs D 2.5, p<0.001). Yet at follow-up, doctors record freedom from angina (CCS=0) in a more substantial proportion of the population, considerably more so than patients self-report (p<0.0001) (Abstract 40 figure 2). The published results of the SOS trial used doctor gradings to report freedom from angina at 1 year in 79% of CABG patients vs 66% of PCI patients (p<0.0001). If patient gradings are used instead these figures are reduced to 57% in CABG and 44 % in PCI (p<0.0001), rendering both treatment strategies significantly less effective at relieving angina from a patients perspective (p<0.0001), Abstract 40 table 1.
Conclusions This is the first randomised study to compare the improvement in angina status reported by patients and clinicians following revascularisation therapy for coronary artery disease. The observed trend for doctors to insist that all patients must have some symptoms at baseline, and more importantly, to suggest that a greater proportion of patients have been rendered symptom free at follow-up (than is suggested by self-reported estimates) has important implications and may call into question our current understanding of the impact of revascularisation.
- coronary intervention