Complex and high-risk intervention in indicated patients (CHIP) in contemporary clinical practice

Recently, there has been a growing interest in the concept of complex and high-risk intervention in indicated patients (CHIP). In our previous studies, we defined the three CHIP components (complex PCI, patient factors, and complicated heart disease), and introduced a novel stratification based on patient factors and/or complicated heart disease. We divided patients undergoing complex PCI into the definite CHIP, the possible CHIP, and the non-CHIP groups. Definite CHIP was defined as complex PCI for patients with both patient factors and complicated heart disease, and possible CHIP was defined as complex PCI for patients with either patient factors or complicated heart disease. Of note, even if a patient has both patients' factors and complicated heart disease, non-complex PCI is not a CHIP-PCI. In this review article, we discussed the determinants of complications in CHIP-PCI, long-term outcomes after CHIP-PCI, mechanical circulatory support devices for CHIP-PCI, and the goal of CHIP-PCI. Although CHIP-PCI attracts rising attention in contemporary PCI, clinical studies that investigate the clinical implications of CHIP-PCI are still sparse. Further studies are warranted to optimize CHIP-PCI.