Abstract 4214: Vasodilation of Coronary Artery After Stenting: Choosing the Correct Stent Size in Tight Stenosis
Aim: In very tight stenoses, distal coronary pressure is markedly lower than the aortic pressure. After stenting this distal pressure (distension pressure) is re-established. We aimed at quantifying the effect of these acute changes in pressure on the arterial diameter of the segment proximal and distal to the stented segment.
Method: 35 patients with angiographically moderate to tight stenosis (mean diameter stenosis 74%) were included. The pressure proximal and distal to the stenotic segment (pressure wire) as well as the arterial diameter (QCA) of 1.5 cm proximal and 1.5 cm distal to the site of the stent implantation was obtained
after intracoronary nitrates,
after successful stent implantation.
Results: The mean diameter of the proximal coronary segment was 2.76 mm±0.09, 2.95 mm±0.09 (+ 6.8%) and 3.14 mm±0.09 (+ 13%) at baseline, after nitrates and after stent implantation respectively, ANOVA, p=0.02. The mean diameter of the distal coronary segment was 2.06 mm±0.11, 2.26 mm±0.11 (+ 9.7 %) and 2.55 mm±0.1 (+ 23.8%) at baseline, after nitrates and after stent implantation respectively, ANOVA, P=0.007. There was a significant correlation between the increase in distal diameter and increase in distal pressure due to stent implantation (r=0.57, P=0.0003): the tighter the lesion, the larger the expected increase in diameter.
Conclusion: In tight coronary stenoses, a marked increase in vessel diameter occurs after re-establishment of a normal distension pressure (and normal shear stress). This should be taken into account when choosing the stent diameter and is an argument to discourage direct stenting in these lesions.