MOORSELBAAN – Researchers at OLV Hospital, Moorselban, have reported today in the journal Circulation: Cardiovascular interventions an important observation relating to the choice of stent diameter in the treatment of moderate-to-severe stenosis. The key finding was that the diameter of the coronary artery increased once the normal distending pressure is returned. This means that when choosing the size of stent, it is not enough to look at the current diameter alone.

Through a study of 48 patients with angiographically-verified moderate-to-severe stenosis, involving proximal and distal measurement of blood pressure (relative to the stenosis), and a subsequent treatment using a graded stenosis (8 persons). The graded stent allows for control over the stenosis form during its inflation using a balloon catheter, and is in contrast to the use of a directly implanted stent.

Oliver Muller and colleagues write that “the mean diameter of the proximal coronary segment was 2.75±0.08 mm, 2.92±0.08 mm (+7.4%), and 3.10±0.07 mm (+14.7%) at baseline, after nitrates and after PCI, respectively (P<0.001). The mean diameter of the distal coronary segment was 2.07±0.09 mm, 2.23±0.09 mm (+9.7%), and 2.5±0.07 mm (+28.4%) at baseline, after nitrates and after PCI, respectively (P<0.001). The increase in distal diameter correlated significantly with the increase in distal pressure after PCI (r²=0.57; P<0.001). When graded stenoses were created, a decrease in diameter of 18±4% was observed with a pressure drop of 43±5 mm Hg”

Two key conclusions are drawn; first, the importance of taking into account this effect when determining stent diameter, and second, the implied advantage of using a graded stent rather than direct.