Effect of Direct Stent Implantation on QTc Dispersion

The aim of this study was to evaluate whether direct stenting is superior to conventional stent implantation technique with respect to QTc dispersion in prospectively selected patients with simple lesion morphology and class II stable angina undergoing elective coronary stenting. One hundred thirty-four consecutive patients were divided into 2 groups based on the stenting technique used: the direct stenting without predilation group, group I (n = 64), and the stenting with predilation group, group II (n = 70). All patients had single-vessel disease. The primary end point of the study was the QTc dispersion at the 24th hour and at the first month after the procedure and the secondary end point of the study was the major clinical events (MCEs) rate in the hospital period and up to 1 month. Baseline maximum QTc, minimum QTc, and QTc dispersion were not different between the 2 groups. QTc dispersion decreased from 47+/-8 msec before stent implantation to 41+/-11 msec at 24 hours and 37+/-7 msec 1 month after angioplasty in group I (p < 0.006 and p < 0.01, respectively), whereas QTc dispersion decreased from 49+/-9 msec before stent implantation to 46+/-8 msec at 24 hours and 42+/-10 msec 1 month after angioplasty in group II (p < 0.03 and p < 0.01, respectively). Compared with group II, the decrease in QTc dispersion was significantly greater at the 24th hour and at the first month after the procedure in group I (p < 0.003 and p < 0.001, respectively). There was a decreased trend toward MCE rate in group I in relation to that of group II, but the statistical difference was not significant. Direct stenting is a feasible and safe technique. It is superior to conventional stenting technique in decreasing the QTc dispersion at the 24th hour and at the first month after the procedure, whereas it is equivalent to single-vessel conventional stent implantation technique with respect to MCEs rate in the short-term period.