Objectives: To summarize the process and extent of interphysician agreement within two panels convened to derive indications for the appropriate use of coronary angiography and for coronary revascularization procedures.
Participants: Two panels, each with nine practitioners.
Methods: Panelists rated the appropriateness of intervention for a comprehensive set of indications for each procedure. Indications were brief profiles created by combining and permuting clinical characteristics pertinent to case selection for intervention. Ratings were first made at home, with a second round at the panel meeting following open discussion. Final rankings of indications as 'appropriate', 'uncertain' or 'inappropriate' were based on the pattern of panelists' responses on a nine-point scale, including the median rating and extent of agreement among panelists. Agreement was defined as at least seven panelists' ratings within the three-point region containing the median rating. Panelists were later mailed a much-reduced list of indications for which there was agreement on appropriateness. These were re-rated on a necessity scale. A procedure was rated 'necessary' only if a physician was ethically obligated to recommend it as the preferred treatment option.
Results: For appropriateness of angiography, agreement occurred in 38.2% of indications in round 1 and 64.4% in round 2 (P < 0.0001). For coronary artery bypass graft (CABG) versus medical therapy, the corresponding increase was from 43.5 to 54.0% (P < 0.0001). Agreement on necessity of angiography occurred for 44.3% of scenarios. For indications where CABG alone was appropriate, agreement on necessity was 56%. However, for indications where percutaneous transluminal coronary angioplasty (PTCA) could be regarded as the first-line intervention, agreement on necessity was only 5%.
Conclusions: A two-step panel process permitted considerable convergence of panelists' ratings, highlighting the importance of formal panel methods in setting utilization management criteria. However, the extent of continuing disagreement on ratings underscores the need to avoid a forced consensus; instead, divergent opinions should be taken as indicative of uncertainty about the appropriateness of intervention. Interpanelist agreement on necessity ratings was modest, but may help in setting benchmarks to assess possible underprovision of invasive cardiac services in Canada.