Limitations
bleeding, CKD
EVENT, BLEEDING
This study has several limitations. First, an uneven proportion of choice for intravascular imaging devices resulted in only a small fraction of OCT, and its benefit and harm could not be accurately compared with IVUS or angiography alone. A relatively small CKD population also limits interpretation from the comparison of outcomes among the 3 groups. Therefore, this was a hypothesis-generating study. Second, as with the main study, masking of the operator was impossible due to the different study procedures for stent implantations. However, precisely defined criteria of angiography and imaging-based optimization, quantitative coronary angiography analysis at the core laboratories, and blinded clinical event adjudication was conducted to minimize the risk of potential bias. Third, as intravascular imaging-based measurement is impossible in the angiography-guided PCI group, the only available data to explain the differences in outcomes were data from quantitative coronary angiography. Fourth, as this was a substudy that was not dedicated to patients with CKD, mid- to long-term kidney-related outcomes were missing. In addition, there was not a specific protocol for reducing contrast volume using intravascular imaging in patients with CKD. Fifth, although bleeding is an important factor in patients with CKD that could have affected the adverse outcomes, these data were unavailable in the current study.