Reproducibility and factors influencing the assessment of the SYNTAX score in the left main Xience study

As assessment of SYNTAX score is made by visual estimate of coronary angiography, discrepancies between evaluations by different observers and the impact of observer experience have not yet been evaluated.

Using the data of 166 patients with unprotected left main lesions treated with the second generation everolimus-eluting stent, we sought to analyze SYNTAX score assessment provided by one junior and two independent senior observers and to assess the impact of the quality of angiographies on the reproducibility of SYNTAX score determination. Intra-observer variability was assessed by a senior observer by analyzing 50 sets of angiograms after an interval of at least 6 weeks.

The weighted kappa value for the inter-observer reproducibility of SYNTAX score classified as tertiles, according to SYNTAX trial, was 0.71 and the intra-observer weighted kappa value was 0.79. When compared with junior's measurements, SYNTAX score assessed by senior investigators was 0.46 and 0.50. Changes in SYNTAX score classification were arbitrarily responsible for changes in weighted kappa values. Angiograms showing the higher rates of discrepancies between observers were of lower quality, when compared with random angiograms. SYNTAX score was closely correlated to 1-year incidence of major adverse cerebro- and cardiovascular events for both junior and senior readers.

SYNTAX score was slightly underestimated by junior reader, when compared with experienced operators. Inter- and intra-observer reproducibility of experienced operators was very acceptable. SYNTAX score evaluation was clearly related to the quality of angiograms. SYNTAX score was correlated to 1-year incidence of major cardiac and cerebrovascular events (MACCE) in all readers.