Effect of variability in the interpretation of coronary angiograms on the appropriateness of use of coronary revascularisation procedures

Background Evidence from numerous studies of coronary angiography show diff erences between observers' assessments of 15% to 45%. The implication of th is variation is serious: If readings are erroneous, some patients will unde rgo revascularization procedures unnecessarily and others will be denied an essential treatment. We evaluated the variation in interpretation of angio grams and its potential effect on appropriateness of use of revascularizati on procedures. Methods and Results Angiograms of 308 randomly selected patients previously studied for appropriateness of angiography, coronary artery bypass graftin g (CABG), and percutaneous transluminal coronary angioplasty (PTCA) were in terpreted by a blinded panel of 3 experienced angiographers and compared wi th the original interpretations. The potential effect on differences on the appropriateness of revascularization was assessed by use of the RAND crite ria. Technical deficiencies were found in 52% of cases. Panel readings fend ed to show less significant disease (none in 16% of vessels previously read as showing significant disease), less severity of stenosis (43% lower, 6% higher), and lower extent of disease (23% less, 6% more). The classificatio n of CABG changed from necessary/appropriate to uncertain/inappropriate for 17% to 33% of cases when individual ratings were replaced by panel reading s. Conclusions The general level of technical quality of coronary angiography is unsatisfactory, Variation in the interpretation of angiograms was substa ntial in all measures and tended to be higher in individual than in panel r eadings. The effect was to lead to a potential overestimation of appropriat eness of use of CABG by 17% and of PTCA by 10%. These findings indicate the need for increased attention to the technical quality of studies and an in dependent second reading for angiograms before recommending revascularizati on.