Coronary stent implantation technique: prolonged inflation time maximizes stent expansion

To determine whether longer periods of stent balloon inflation result in greater minimal luminal diameter (MLD) as measured by quantitative coronary analysis (QCA), and to determine whether measured size correlated with that predicted by pressure-diameter nomograms.

Seventy-four stents were implanted in 52 patients. Stent acquisitions at a steady inflation pressure were taken at 10 s, 30 s, and 60 s. The stent MLD at each of these intervals was measured by QCA. Comparisons were made between (1) stent diameter obtained at these time intervals; and (2) nomogram-predicted pressure-related stent diameters.

Measured stent size increased significantly between each time point measured, with the most marked increment in size (0.15 ± 0.02 mm) observed between 10 s and 30 s (P<.0001), with a smaller but still significant increment between 30 s and 60 s (0.06 ± 0.02 mm; P=.0034). Although there was good correlation between measured size and expected size at 10 s and 30 s (r² = 0.60 and 0.58, respectively), the correlation at 60 s inflation was strongest (r² = 0.65).

Longer durations of stent inflation increase MLD. A minimum duration of 30 seconds is recommended. However, even after 60 s, the MLD does not match the nomogram-derived expected diameter.