Avaliação tardia de endopróteses coronarianas com sirolimus: comparação da tomografia computadorizada por múltiplos detectores com a angiografia quantitativa e o ultra-som intracoronariano

Abstract

objective: To assess the performance of multidetector computed tomography in determining late clinical outcomes of patients undergoing sirolimus-eluting stent implantation.Methods: Thirty patients, successfully submitted to sirolimus-eluting stent implantation for more than six months, were selected to participate in the study. All underwent invasive angiography and intravascular ultrasound following CT angiography using iodinated contrast medium at a dose of 1.5 ml/kg. Results:Mean proximal reference diameter was 3.01 ± 0.31 mm by tomography and 3.14 ± 0.31 mm by angiography (p = 0.04). When the left circumflex artery was excluded from the analysis, the difference between both examinations was no longer significant (tomography = 3.01 ± 0.32 mm; angiography = 3.10 ± 0.30 mm, p = 0.65). Mean distal reference diameter was 2.86 ± 0.30 mm by tomography and 2.92 ± 0.32 by angiography (p = 0.25). Mean in-stent minimal lumen diameter was 2.85 ± 0.25 mm by tomography and 2.85 ± 0.29 mm by angiography (p = 0.27). Mean minimal in-stent crosssectional area was 7.19 ± 1.47 mm 2 by tomography and 6.90 ± 1.52 mm 2 by intravascular ultrasound (p = 0.36), but there was only a weak correlation between these measurements (r = 0.33). Conclusion:Computed tomography allows the qualitative assessment of sirolimus-eluting stents, accurate estimate of proximal and distal reference diameters of the target vessel, and in-stent minimal lumen diameter. Its correlation with measurements performed using intravascular ultrasound, however, is less strong. key words: Coronary failure, computed tomography, quantitative angiography, intravascular ultrasound.

A avaliação do stent coronariano pela tomografia computadorizada cardiovascular

“…Even though in the final table this indication has been ranked as IIb, I believe that, in the symptomatic patient, it could potentially be considered as IIa level, given the tremendous technological advances offered by 64-slice CT scanners 4 . This discussion emphasizes the importance of the quantitative data presented by Pinto et al 3 .…”

“…In fact, the ability of new scanners to detect in-stent stenosis depends on a range of technical aspects, such as the type and design of the metal alloy the stent is made of, stent final diameter and expansion, the X-ray beam angle relative to the stent, spatial resolution (now with an isotropic voxel size of 0.35 mm 3 ), acquisition and reconstruction techniques (such as the convolution kernel that controls the signal-to-noise ratio), contrast agent concentration, X-ray tube capacity, and heart rate and frequency at the time of image acquisition, among others. Depending on how well these factors act together, instent luminal images may be accurate or hampered by artifacts, particularly the blooming effect and intraluminal dark images mimicking neointimal hyperplasia, but that are, in fact, the result of beam hardening.…”