Determinants of serious in-hospital complications in patients with Killip class 1/2 ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention.

Killip classification has been used to stratify the risk of patients with acute myocardial infarction (AMI). There were many reports that Killip class 3 or 4 is closely associated with poor clinical outcomes. In other words, Killip class 1 or 2 is associated with favorable clinical outcomes in patients with AMI, especially when patients received primary percutaneous coronary intervention (PCI). However, some patients with Killip class 1/2 suffer from serious in-hospital complications. This study aimed to identify factors associated with serious in-hospital complications of ST-segment elevation myocardial infarction (STEMI) in patients with Killip class 1/2. The primary endpoint was serious in-hospital complications defined as the composite of in-hospital death and mechanical complications. We included 809 patients with STEMI, and divided them into the non-complication group (n = 791) and the complication group (n = 18). In-hospital death was observed in 14 patients (1.7%), and mechanical complications were observed in 4 patients (0.5%). Final TIMI flow ≤ 2 was more frequently observed in the complication group (33.3%) than in the non-complication group (5.4%) (p < 0.001). Multivariate logistic regression analysis revealed that serious in-hospital complication was associated with final TIMI flow grade ≤ 2 (Odds ratio 6.040, 95% confidence interval 2.042-17.870, p = 0.001). In conclusion, serious in-hospital complication of STEMI was associated with insufficient final TIMI flow grade in patients with Killip class 1/2. If final TIMI flow grade is suboptimal after primary PCI, we may recognize the potential risk of serious complications even when patients presented as Killip class 1/2.

Clinical Impact of In-Stent Calcification in Coronary Arteries: Optical Coherence Tomography Study.

In-stent restenosis with neoatherosclerosis has been known as the predictor of target lesion revascularization (TLR) after percutaneous coronary intervention. However, the impact of in-stent calcification (ISC) alone on clinical outcomes remains unknown since neoatherosclerosis by optical coherence tomography includes in-stent lipid and calcification. We aimed to assess the effect of ISC on clinical outcomes and clinical differences among different types of ISC. We included 126 lesions that underwent optical coherence tomography-guided percutaneous coronary intervention and divided those into the ISC group (n = 38) and the non-ISC group (n = 88) according to the presence of ISC. The cumulative incidence of clinically driven TLR (CD-TLR) was compared between the ISC and non-ISC groups. The impact of in-stent calcified nodule and nodular calcification on CD-TLR was evaluated using the Cox hazard model. The incidence of CD-TLR was significantly higher in the ISC group than in the non-ISC group (p = 0.004). In the multivariate Cox hazard model, ISC was significantly associated with CD-TLR (hazard ratio [HR] 3.58, 95% confidence interval [CI] 1.33 to 9.65, p = 0.01). In-stent calcified nodule/nodular calcification and in-stent nodular calcification alone were also the factors significantly associated with CD-TLR (HR 3.34, 95%CI 1.15 to 9.65, p = 0.03 and HR 5.21, 95%CI 1.82 to 14.91, p = 0.002, respectively). ISC without in-stent calcified nodule/nodular calcification, which was defined as in-stent smooth calcification, was not associated with CD-TLR. In conclusion, ISC was associated with a higher rate of CD-TLR. The types of calcifications that led to a high rate of CD-TLR were in-stent calcified nodule/nodular calcification and in-stent nodular calcification alone but not in-stent smooth calcification. In-stent calcified nodule and nodular calcification should be paid more attention.

Determinants of successful parallel wire technique in percutaneous coronary intervention to coronary chronic total occlusion.

BACKGROUND: Many techniques and concepts have been developed in the field of percutaneous coronary intervention to chronic total occlusion (CTO). Parallel wire technique (PWT) is still an important technique in antegrade approach. The purpose of this study was to identify the determinants of successful PWT in coronary CTO. METHODS: We reviewed consecutive 451 CTO lesions that were treated with PCI in our medical center. The overall success rate of PCI to CTO during the study period was 92.2 % (416/451). Of 451 CTO lesions, we excluded 333 CTO lesions in which PTW was not performed. We included 118 CTO lesions in which PWT was performed, and divided them into the successful PWT group (n = 65) and the unsuccessful PWT group (n = 53) according to the procedure success of PWT. Multivariate logistic regression analysis were performed to find the determinants of successful PWT. RESULTS: The prevalence of the sufficient clarity of CTO exit site was significantly higher in the successful PWT group (46.2 %) than in the unsuccessful PWT group (11.3 %) (p < 0.01). Multivariate logistic regression analysis revealed that the J-CTO score was inversely associated with successful PWT (OR 0.66, 95 % CI 0.44-0.99, P = 0.04), whereas the sufficient clarity of CTO exit site was associated with successful PWT (OR 5.16, 95 % CI 1.75-15.20, P < 0.01). CONCLUSIONS: The J-CTO score was inversely associated with successful PWT, whereas the sufficient clarity of CTO exit site was associated with successful PWT. The low J-CTO score and the sufficient clarity of CTO exit site may be the determinants of successful PWT.

Halftime rotational atherectomy: a unique concept for diffuse long severely calcified lesions.

Rotational atherectomy (RA) is technically more difficult in a diffuse calcified lesion than in a focal calcified lesion. We hypothesized that taking a halftime can be another option for RA to the diffuse calcified lesions. Halftime was defined as at least one long break during RA, in which an operator pulled out the Rotablator system from the guide catheter before crossing the lesion. This study aimed to compare the complications between RA with and without halftime. We included 177 diffuse long severely calcified lesions (lesion lengths ≥ 30 mm) that required RA, and divided those lesions into a halftime group (n = 29) and a no-halftime group (n = 148). The primary outcome was periprocedural myocardial infarction (MI). The reference diameter was smaller in the halftime group than in the no-halftime group [1.82 (1.70-2.06) mm versus 2.17 (1.89-2.59) mm, p = 0.002]. The total run time was longer in the halftime group than in the non-halftime group [133.0 (102.0-223.0) seconds versus 71.5 (42.0-108.0) seconds, p < 0.001]. Although creatinine kinase (CK) and CK-myocardial band (MB) was significantly higher in the halftime group than in the no-halftime group [CK: 156 (97-308) U/L versus 99 (59-216) U/L, p = 0.021; CK-MB: 15 (8-24) U/L versus 5 (3-15) U/L, p < 0.001], periprocedural MI was not observed in the halftime group. In conclusion, periprocedural MI was not observed in RA with halftime. This preliminary study suggests that halftime RA may be a safe option for diffuse severely calcified lesions.

Changing Trends in Mechanical Circulatory Support Use and Outcomes in Patients Undergoing Percutaneous Coronary Interventions for Acute Coronary Syndrome Complicated With Cardiogenic Shock: Insights From a Nationwide Registry in Japan.

BACKGROUND: Temporal trends in the management of acute coronary syndrome complicated with cardiogenic shock after the revision of guideline recommendations for intra-aortic balloon pump (IABP) use and the approval of the Impella require further investigation, because their impact remains uncertain. METHODS AND RESULTS: Using the Japanese Percutaneous Coronary Intervention (J-PCI) registry database from 2019 to 2021, we identified 12 171 patients undergoing percutaneous coronary intervention for acute coronary syndrome complicated with cardiogenic shock under mechanical circulatory support. The patients were stratified into 3 groups: (1) IABP alone, (2) Impella, and (3) venoarterial extracorporeal membrane oxygenation (VA-ECMO); the VA-ECMO group was further stratified into (3a) VA-ECMO alone, (3b) VA-ECMO in combination with IABP, and (3c) VA-ECMO in combination with Impella. The quarterly prevalence and outcomes were reported. The use of IABP alone decreased significantly from 63.5% in the first quarter of 2019 to 58.3% in the fourth quarter of 2021 (P for trend=0.01). Among 4245 patients requiring VA-ECMO, the use of VA-ECMO in combination with IABP decreased significantly from 78.7% to 67.3%, whereas the use of VA-ECMO in combination with Impella increased significantly from 4.2% to 17.0% (P for trend <0.001 for both). After adjusting for the confounders, the risk difference in the fourth quarter of 2021 relative to the first quarter of 2019 for in-hospital mortality was not significant (adjusted odds ratio, 0.84 [95% CI, 0.69-1.01]). CONCLUSIONS: Our study revealed substantial changes in the use of different mechanical circulatory support modalities in acute coronary syndrome complicated with cardiogenic shock, but they did not significantly improve the outcomes.

Impact of the Japanese Version of High Bleeding Risk Criteria on Clinical Outcomes in Patients with ST-segment Elevation Myocardial Infarction.

AIMS: Bleeding complications are often observed in patients with ST-segment elevation myocardial infarction (STEMI). Although the Japanese version of the high bleeding risk criteria (J-HBR) were established, it has not been sufficiently validated in patients with STEMI. This retrospective study aims to examine whether J-HBR is associated with cardiovascular and bleeding events in patients with STEMI. METHODS: We included 897 patients with STEMI and divided them into the J-HBR group (n=567) and the non-J-HBR group (n=330). The primary endpoint was the major adverse cardiovascular events (MACE), defined as the composite of all-cause death, non-fatal myocardial infarction, ischemic stroke, and systemic embolism. Another primary endpoint was total bleeding events defined as type 3 or 5 bleeding events as defined by the Bleeding Academic Research Consortium . RESULTS: During the median follow-up duration of 573 days, 187 MACE and 141 total bleeding events were observed. The Kaplan-Meier curves showed that MACE and total bleeding events were more frequently observed in the J-HBR group than in the non-J-HBR group (p＜0.001). Multivariate Cox hazard analysis revealed that after controlling for multiple confounding factors, the J-HBR group was significantly associated with MACE (hazard ratio [HR] 4.676, 95% confidence interval (CI) 2.936-7.448, p＜0.001) and total bleeding events (HR 6.325,95% CI 3.376-11.851, p＜0.001). CONCLUSIONS: J-HBR is significantly associated with MACE and total bleeding events in patients with STEMI. This study validated J-HBR as a risk marker for bleeding events and suggests J-HBR as a potential risk marker for MACE in patients with STEMI.

A unique mechanism of restenosis after drug-coated balloon in peripheral artery: Insight from optical frequency domain imaging.

Drug-coated balloons (DCBs) have been widely used in endovascular therapy for femoropopliteal arteries with atherosclerotic lesions. Vascular response after DCBs remains unclear. This mini-review proposes a possible mechanism of restenosis after the DCB strategy. Balloon dilatation including DCBs expands the vascular lumen by producing dissections, which is composed of the original vascular lumen and the cavity surrounded by dissected flaps. The cavity surrounded by dissected flaps is eventually replaced with the thrombus in the healing process after balloon dilatation. However, the thrombus may propagate to the expanded vascular lumen through the entry point of the dissection. Subsequently, the thrombus both in the cavity and the expanded lumen would be organized over time. The vascular lumen in the chronic-phase after DCBs may be influenced by the propagated thrombus from the cavity surrounded by dissected flaps.

Impact of Excessive Increase in Systolic Blood Pressure after Exercise on Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction.

OBJECTIVE: Although the clinical outcomes for patients with ST-elevation myocardial infarction (STEMI) have improved significantly, some patients still experience poor clinical outcomes. The available risk classifications focus on the short-term outcomes, and it remains important to find high-risk features among patients with STEMI. In Japan, the 200 m walk electrocardiogram (ECG) test is widely performed before discharge. The purpose of this study was to investigate the association between the excessive increase in systolic blood pressure (SBP) following a 200 m walk and the long-term clinical outcomes in patients with STEMI. METHODS: We included 680 patients with STEMI and divided those into an excessive increase in SBP group (n = 144) and a non-excessive increase in SBP group (n = 536) according to the SBP increase after a 200 m walk ECG test. We defined an excessive increase in SBP as SBP ≥ 20 mmHg either just after or 3 min after a 200 m walk ECG test. The primary endpoint consisted of major cardiovascular events (MACE), defined as the composite of all-cause death, non-fatal myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization. RESULTS: The median follow-up duration was 831 days. MACE was more frequently observed in the excessive increase in SBP group (24.3%) than in the non-excessive increase in SBP group (15.1%). Multivariate Cox hazard analysis revealed that the excessive increase in SBP was significantly associated with MACE (HR 1.509, 95% CI: 1.005-2.267, p = 0.047) after controlling for multiple confounding factors. CONCLUSION: An excessive increase in SBP after the 200 m walk ECG test was significantly associated with MACE in patients with STEMI. The 200 m walk ECG test is simple and low-cost, but may help to identify high-risk patients with STEMI.

Development of a simple prediction model for mechanical complication in ST-segment elevation myocardial infarction patients after primary percutaneous coronary intervention.

Mechanical complication (MC) is a rare but serious complication in patients with ST-segment elevation myocardial infarction (STEMI). Although several risk factors for MC have been reported, a prediction model for MC has not been established. This study aimed to develop a simple prediction model for MC after STEMI. We included 1717 patients with STEMI who underwent primary percutaneous coronary intervention (PCI). Of 1717 patients, 45 MCs occurred after primary PCI. Prespecified predictors were determined to develop a tentative prediction model for MC using multivariable regression analysis. Then, a simple prediction model for MC was generated. Age ≥ 70, Killip class ≥ 2, white blood cell ≥ 10,000/µl, and onset-to-visit time ≥ 8 h were included in a simple prediction model as "point 1" risk score, whereas initial thrombolysis in myocardial infarction (TIMI) flow grade ≤ 1 and final TIMI flow grade ≤ 2 were included as "point 2" risk score. The simple prediction model for MC showed good discrimination with the optimism-corrected area under the receiver-operating characteristic curve of 0.850 (95% CI: 0.798-0.902). The predicted probability for MC was 0-2% in patients with 0-4 points of risk score, whereas that was 6-50% in patients with 5-8 points. In conclusion, we developed a simple prediction model for MC. We may be able to predict the probability for MC by this simple prediction model.

Impact of controlled blood pressure and pulse rate at discharge on clinical outcomes in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Although major guidelines recommend the routine introduction of angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) and beta-blockers for patients with ST-segment elevation myocardial infarction (STEMI), evidence regarding the target blood pressure (BP) or pulse rate (PR) at hospital discharge is sparse. This retrospective study aimed to compare the clinical outcomes in patients with STEMI between those with good BP and PR control and those with poor BP or PR control. METHODS: We included 748 patients with STEMI who received both ACE inhibitors/ARBs and beta-blockers at hospital discharge, and divided them into a good control group (systolic BP ≤140 mmHg and PR ≤80 bpm, n = 564) and a poor control group (systolic BP >140 mmHg or PR >80 bpm, n = 184). The primary endpoint was major cardiovascular events (MACE) defined as the composite of all-cause death, non-fatal myocardial infarction, and re-admission for heart failure. RESULTS: During the median follow-up duration of 568 days, a total of 119 MACE were observed. The Kaplan-Meier curves showed that MACE were more frequently observed in the poor control group (p = 0.009). In the multivariate Cox hazard analysis, the good control group was inversely associated with MACE (HR 0.656, 95 % CI: 0.444-0.968, p = 0.034) after controlling for multiple confounding factors. CONCLUSIONS: The good control of systolic BP and PR at discharge was inversely associated with long-term adverse events in STEMI patients treated with both ACE inhibitors/ARBs and beta blockers. This study suggests the importance of titration of ACE inhibitors/ARBs and beta-blockers for better clinical outcomes in patients with STEMI.

Appetite Predicts Long-Term Clinical Outcomes in Patients with Acute Myocardial Infarction.

BACKGROUND: Recently, the nutritional status of patients has drawn attention in an aging society. Early studies have reported that nutritional status is related to long-term outcomes in patients with acute myocardial infarction (AMI). However, it is not necessarily simple to evaluate the nutritional status of patients with AMI. We hypothesized that appetite before discharge can be a predictor for long-term adverse cardiovascular events in patients with AMI. This retrospective study aimed to investigate whether appetite is related to long-term adverse outcomes in patients with AMI. METHODS: This study included 1006 patients with AMI, and divided them into the good appetite group (n = 860) and the poor appetite group (n = 146) according to the percentage of the dietary intake on the day before discharge. Major adverse cardiac events (MACE), which were defined as a composite of all-cause death, non-fatal MI, and re-admission for heart failure, were set as the primary outcome. RESULTS: The median follow-up duration was 996 days, and a total of 243 MACE was observed during the study period. MACE was more frequently observed in the poor appetite group than in the good appetite group (42.5% versus 21.0%, p < 0.001). In the multivariate COX hazard model, poor appetite was significantly associated with MACE (Hazard ratio 1.698, 95% confidence interval 1.243-2.319, p < 0.001) after controlling for multiple confounding factors. CONCLUSION: Appetite at the time of discharge was significantly associated with long-term clinical outcomes in patients with AMI. Patients with poor appetite should be carefully followed up after discharge from AMI.

Association of Increased Inter-arm Blood Pressure Difference with Long-term Clinical Outcomes in Patients with Acute Myocardial Infarction who Underwent Percutaneous Coronary Intervention.

Objective Patients with acute myocardial infarction (AMI) often have peripheral artery disease (PAD). It is well known that the long-term clinical outcomes of AMI are worse in patients with a low ankle-brachial index (ABI) than in patients with a preserved ABI. Unlike ABI, the association between the inter-arm blood pressure difference (IABPD) and clinical outcomes in patients with AMI has not yet been established. This retrospective study examined whether or not the IABPD is associated with long-term clinical outcomes in patients with AMI. Methods We included 979 patients with AMI and divided them into a high-IABPD group (IABPD ≥10 mmHg, n=31) and a low-IABPD group (IABPD <10 mmHg, n=948) according to the IABPD measured during hospitalization for AMI. The primary endpoint was the all-cause mortality rate. Results During a median follow-up duration of 694 days (Q1, 296 days; Q3, 1,281 days), 82 all-cause deaths were observed. Kaplan-Meier curves showed that all-cause death was more frequently observed in the high-IABPD group than in the low-IABPD group (p<0.001). A multivariate Cox hazard analysis revealed that a high IABPD was significantly associated with all-cause death (hazard ratio 2.061, 95% confidence interval 1.012-4.197, p=0.046) after controlling for multiple confounding factors. Conclusion A high IABPD was significantly associated with long-term all-cause mortality in patients with AMI. Our results suggest the usefulness of the IABPD as a prognostic marker for patients with AMI.

Lifetime management of severely calcified coronary lesions: the treatment algorithm focused on the shape of calcification.

The concept of lifetime management has not been discussed in the field of percutaneous coronary intervention (PCI), because the durability of drug-eluting stent (DES) is considered to be long enough for most patients. Furthermore, even if in-stent restenosis occurs, the treatment for in-stent restenosis is simple in most cases. On the other hand, the long-term clinical outcomes after DES implantation are worse in severely calcified coronary lesions than in non-calcified lesions. Moreover, the treatment for in-stent calcified restenosis or restenosis due to stent underexpansion is not simple. The concept of lifetime management of severely calcified lesions may be necessary like that of aortic stenosis. Recently, several algorithms have been published in PCI to severely calcified lesions, partly because of the emergence of IVL. These algorithms focus on the selection of cracking and debulking devices for the preparation of stenting. However, the optimal stent expansion does not guarantee the long-term patency, when the target lesion includes calcified nodules. Stent restenosis due to calcified nodules is difficult to manage. In this review article, we propose the algorithm for severely calcified lesions focused on the shape of calcification. We do not need to hesitate stenting when multiple cracks on circumferential calcification are observed by intravascular imaging devices. However, DCB may be an option as final device in some situations, when lifetime management of severely calcified lesions is considered.

Rotational atherectomy to left circumflex ostial lesions: tips and tricks.

Serious complications including vessel perforation may occur during rotational atherectomy (RA) to left circumflex (LCX) ostial lesions. In fact, if perforation occurs around LCX ostium, bailout procedures including deployment of covered stents may cause fatal ischemia in the territory of left anterior descending artery, which results in broad anterior acute myocardial infarction and subsequent death. In this review article, we described tips and tricks for RA to LCX ostial lesions. First, we should cautiously decide the indication for RA to LCX ostial lesions, because there are several reasons to avoid RA to LCX ostial lesions. Before procedures, we should estimate the difficulty of RA to LCX ostial lesions, which is mainly determined by the combination of the bifurcation angle and the severity of stenosis. Thus, the combination of the large bifurcation angle and the tight stenosis makes RA to LCX ostial lesions most difficult. Appropriate position of guide catheter and RotaWire is a key to successful RA to LCX ostial lesions. Differential cutting is an essential concept for RA to LCX ostial lesions. However, since there is no guarantee that differential cutting always works, small burr (≤ 1.5 mm) would be a safe choice as initial burr for RA to LCX ostial lesions.

Teneligliptin, a DPP-4 Inhibitor, Improves Vascular Endothelial Function via Divergent Actions Including Changes in Circulating Endothelial Progenitor Cells.

Purpose: Dipeptidyl peptidase-4 (DPP-4) inhibitors increase endothelial progenitor cells (EPCs) in peripheral blood circulation. However, the underlying mechanisms and effects on vascular endothelial function remain unclear. We evaluated whether the DPP-4 inhibitor teneligliptin increases circulating EPCs by inhibiting stromal-derived factor-1α (SDF-1α) and improves flow-mediated vascular dilatation (FMD) in type 2 diabetes mellitus patients with acute coronary syndrome (ACS) or its risk factors. Patients and Methods: This single-center, open-label, prospective, randomized controlled trial evaluated 17 patients (hemoglobin A1c ≤7.5% and peak creatinine phosphokinase <2000 IU/mL) with ACS or a history of ACS or multiple cardiovascular risk factors. Metabolic variables of glucose and lipids, circulating EPCs, plasma DPP-4 activity, and SDF-1α levels, and FMD were evaluated at baseline and 28 ± 4 weeks after enrollment. Patients were randomly assigned to either the teneligliptin (n = 8) or control (n = 9) groups. Results: The DPP-4 activity (∆-509.5 ± 105.7 vs ∆32.8 ± 53.4 µU/mL) and SDF-1α levels (∆-695.6 ± 443.2 vs ∆11.1 ± 193.7 pg/mL) were significantly decreased after 28 weeks in the teneligliptin group than those in the control group. The number of EPCs showed an increasing trend in the teneligliptin treated group; albeit this did not reach statistical significance. Glucose and lipid levels were not significantly different between the groups before and after 28 weeks. However, FMD was significantly improved in the teneligliptin group when compared to the control group (∆3.8% ± 2.1% vs ∆-0.3% ± 2.9%, P=0.006). Conclusion: Teneligliptin improved FMD through a mechanism other than increasing the number of circulating EPCs.

Comparison of Long-Term Clinical Outcomes of Elective Percutaneous Coronary Intervention Between Complex and High-risk Intervention in Indicated Patients (CHIP) versus Non-CHIP.

Recently, there has been a growing interest in complex and high-risk intervention in indicated patients (CHIP) in the contemporary percutaneous coronary intervention (PCI). CHIP is composed of the following 3 factors: (1) patient factors, (2) complicated heart disease, and (3) complex PCI. However, there are few studies that investigated the long-term outcomes of CHIP-PCI. The purpose of this study was to compare the incidence of long-term major adverse cardiovascular events (MACEs) among the definite CHIP, possible CHIP, and non-CHIP groups in complex PCI. We included 961 patients and divided them into the definite CHIP (n = 129), the possible CHIP (n = 369), and the non-CHIP groups (n = 463). During the median follow-up duration of 573 days (quartile 1:226 days to quartile 3:1,165 days), a total of 189 MACE were observed. The incidence of MACE was highest in the definite CHIP group, followed by the possible CHIP group, and lowest in the non-CHIP group (p = 0.001). Definite CHIP (vs non-CHIP: odds ratio 3.558, 95% confidence interval 2.249 to 5.629, p <0.001) and possible CHIP (vs non-CHIP: odds ratio 2.260, 95% confidence interval 1.563 to 3.266, p <0.001) were significantly associated with MACE after controlling for confounding factors. Among CHIP factors, active malignancy, pulmonary disease, hemodialysis, unstable hemodynamics, left ventricular ejection fraction, and valvular disease were significantly associated with MACE. In conclusion, the incidence of MACE in complex PCI was highest in the definite CHIP group, followed by the possible CHIP group, and lowest in the non-CHIP group. The concept of CHIP should be recognized to predict the long-term MACE in patients who undergo complex PCI.

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.