We thank Dr. Perez de Prado and colleagues for their interest in our article and for noticing the discrepancy in the incidence of malapposition reported in the abstract. As displayed in Figure 2, no significant difference was seen in terms of the observed incidence of malapposition among the 3 groups. An erratum has been submitted for appropriate rectification.

As pointed out, the reference and the lesion diameters were significantly larger in group I (stent diameter/average reference lumen diameter ratio <0.89) but with a similar plaque burden across the 3 groups. Additionally, stent expansion and plaque intrusion were significantly lower in group I, the most undersized drug-eluting stent group. More importantly, the greatest frequency of creatinine kinase-MB elevation >3 times the upper limit of normal was observed in group III only (ratio >1.0), and a strong correlation was demonstrated between the plaque intrusion area/volume and the ratio of the stent diameter to the average intravascular ultrasound reference lumen diameter (Figure 3). Therefore, we strongly believe that the amount of plaque prolapse, which itself is related to the degree of stent expansion, explains the outcome differences in our study. This is also supported by a previous study by Iakovou et al. The association between plaque prolapse and the amount of myonecrosis after stenting has been described in patients with acute myocardial infarction, suggesting that the amount of plaque intrusion and subsequent distal embolization is an underlying mechanism for postpercutaneous coronary intervention cardiac enzyme elevation in saphenous vein grafts.

The undersized stent approach to treat saphenous vein grafts seems to be not only safer compared to the conventional strategy, but also showed similar rates of target lesion and vessel revascularization at 1 year of follow-up. Definitive stent thrombosis, as defined by the Academic Research Consortium, was noted in 2 (0.95%) of 209 cases at 1 year of follow-up. Two cases of subacute thrombosis (days 2 and 12) occurred in group II.

By how much should we undersize the stent in saphenous vein grafts? Consistent with our published data—reported in terms of the stent diameter to mean intravascular ultrasound reference diameter—we recommend sizing the stent ≥10% less than the average reference lumen diameter measured by intravascular ultrasonography. In cases of severe vein graft degeneration, we undersize the stent by 20% to 30%. However, intravascular ultrasonography should not be used before stenting in severe degenerated grafts to prevent embolization, in which case, sizing the stent should be done using angiography and following the same rule. If the lesion is distal in a vein graft, intravascular ultrasonography can be used proximally to assess the vessel size. Nonetheless, we always perform intravascular ultrasonography after stenting to assess the final results.