[Reliability of digital coronary quantification in a hemodynamic laboratory. Comparison with a film-based system]

Quantitative coronary angiography can be performed in two ways: on-line during catheterism, and off-line once the procedure is finished. Consequently, several studies have been published comparing both systems. Nevertheless, none of them has compared the measurements made off-line with those acquired on-line by the hemodynamist in charge of procedure. The objective of this study was to compare the measurements made on-line by the hemodynamist involved in the procedure with a digital system (DCI) with those obtained off-line by an independent and alien observer to the procedure by using film-based system (CMS).

Forty coronary lesions suitable for quantification were measured in a prospective fashion. They came from follow-up angiograms. Either balloon or stent were used in the previous angioplasty. Stenoses were assessed on-line and off-line by using the most severe view as judged by the hemodynamist.

No significant differences were found for obstruction diameter, reference diameter nor percent diameter stenosis. Pearson's correlation coefficient values (r), intraclass correlation coefficient (ri), regression line equation and mean of signed differences with their standard deviations are showed: a) obstruction diameter: r = 0.83, ri = 0.83, DCI = 0.42 + 0.76 x CMS, -0.01 +/- 0.42 mm; b) reference diameter: r = 0.72, ri = 0.69, DCI = 1.29 + 0.61 x CMS, 0.003 +/- 0.38 mm, y c) percent diameter stenosis: r = 0.86, ri = 0.86, DCI = 10.05 + 0.77 x CMS, 1.19 +/- 10.75%.

We attained good concordance between both quantification systems under clinical conditions. In our opinion these results support the use of on-line quantification as a reliable tool for clinical decision making in the catheterization laboratory.