Reliability of digital, coronary quantification as performed in the cath-lab. Comparison with a film-based system

Background and objectives. Quantitative coronary angiography can be perform ed in two ways: on-line during catheterism, and off-line once the procedure is finished. Consequently, several studies have been published comparing b oth systems. Nevertheless, none of them has compared the measurements made off-line with those acquired online by the hemodynamist in charge of proced ure. The objective of this study was to compare the measurements made on-li ne by the hemodynamist involved in the procedure with a digital system (DCI (TM)) with those obtained off-line by an independent and alien observer to the procedure by using film-based system (CMS(TM)). Material and methods. Forty coronary lesions suitable for quantification we re measured in a prospective fashion. They came from follow-up angiograms. Either balloon or stent were used in the previous angioplasty. Stenoses wer e assessed online and off-line by using the most severe view as judged by t he hemodynamist. Results. No significant differences were found for obstruction diameter, re ference diameter nor percent diameter stenosis. Pearson's correlation coeff icient values (r), intraclass correlation coefficient (r(i)), regression li ne equation and mean of signed differences with their standard deviations a re showed: a) obstruction diameter: r = 0.83, r(i) = 0.83, DCI = 0.42 + 0.7 6 x CMS, -0.01 +/- 0.42 mm; b) reference diameter: r = 0.72, r(i) = 0.69, D CI = 1.29 + 0.61 x CMS, 0.003 +/- 0.38 mm, y c) percent diameter stenosis: r = 0.86, r(i) = 0.86, DCI = 10.05 + 0.77 x CMS, 1.19 +/- 10.75%. Conclusions, We attained good concordance between both quantification syste ms under clinical conditions. In our opinion these results support the use of on-line quantification as a reliable tool for clinical decision making i n the catheterization laboratory.