On-pump versus off-pump coronary artery bypass grafting for left main coronary artery disease: long-term outcomes

Introduction

Left main coronary artery disease (LM CAD) requires careful surgical planning because of the extensive myocardial territory at risk and potential hemodynamic instability during revascularization (1,2). Traditionally, surgeons preferred on-pump coronary artery bypass grafting (CABG) for LM CAD due to the stable operative field provided by cardiopulmonary bypass (CPB). However, increasing concerns about CPB-related complications—such as stroke, renal dysfunction, and systemic inflammation—have driven greater interest in off-pump CABG (3). Recent advances in surgical methods, including stabilization devices, anesthetic management, and techniques for proximal anastomosis, have significantly improved the feasibility and safety of off-pump CABG, potentially reducing these complications (4-6). Nevertheless, previous studies comparing off-pump and on-pump CABG outcomes have shown inconsistent results, largely reflecting variations in surgical expertise, institutional practices, and patient selection criteria (7-9).

Given the importance of surgical experience in determining clinical outcomes following off-pump CABG, analyses from centers proficient in both techniques provide valuable insights. This study aims to compare the long-term clinical outcomes between off-pump and on-pump CABG in LM CAD patients within a standardized surgical environment. We hypothesize that off-pump CABG performed by experienced surgeons will demonstrate comparable long-term survival and major adverse cardiovascular events (MACEs) rates relative to on-pump CABG, potentially with fewer perioperative complications. Additionally, identifying patient subgroups that specifically benefit from each surgical approach could further enhance individualized surgical decision-making and overall patient outcomes. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-634/rc).

Methods

Ethical statement

This study was conducted in accordance with the principles embodied in the Declaration of Helsinki and its subsequent amendments. The study protocol was approved by the Institutional Review Board (IRB) of Asan Medical Center (No. 2020-0413). The requirement for the acquisition of informed consent from patients was waived owing to the retrospective nature of this study.

Study population and data sources

This study was a retrospective analysis of 1,484 patients who underwent CABG for significant LM CAD between January 2003 and December 2017 at Asan Medical Center, Seoul, Republic of Korea. Inclusion criteria included LM stenosis ≥70% (visually estimated) or stenosis of 50% to <70% deemed hemodynamically significant based on noninvasive (myocardial perfusion imaging) or invasive testing (fractional flow reserve <0.80, or IVUS with minimum lumen area <6.0 mm² in angiographically unclear cases), with consensus among heart team members on CABG eligibility.

Patients undergoing concomitant cardiac procedures [n=74: aortic valve (n=37), aorta (n=5), mitral and/or tricuspid valve (n=26), left ventricular assist device insertion (n=1), post-infarct ventricular septal defect closure (n=1), patent foramen ovale closure (n=1), and Dor procedure (n=1)] and those presenting with cardiogenic shock (n=2) were excluded. The final study population included 1,410 consecutive patients with significant LM CAD who underwent elective isolated CABG between January 1, 2003, and December 1, 2017 (Figure 1). Data on patient demographics, cardiovascular risk factors, clinical presentation, hemodynamic status, left ventricular function, disease extent, procedure details, and outcomes (in-hospital and follow-up) were collected through a comprehensive review of electronic medical records.

Figure 1 Study flowchart. Among 1,484 CABG patients with LM CAD, 1,410 were included and categorized into off-pump (N=824) and on-pump (N=586) groups after excluding 74 patients who underwent concomitant cardiac procedures. CABG, coronary artery bypass grafting; Dor procedure, endoventricular circular patch plasty; LM CAD, left main coronary artery disease; LVAD, left ventricular assist device; VSD, ventricular septal defect.

Revascularization procedures and follow-up

Patient assignment to surgeons reflected real-world practice based on surgeon availability, on-call schedules, case urgency, and referring physician relationships. All procedures were performed by or under direct supervision of 11 attending cardiac surgeons, with similar involvement of cardiothoracic trainees in both groups. The choice between off-pump and on-pump CABG was guided by (I) patient factors (age, comorbidities, left ventricular function, hemodynamic stability), (II) anatomical factors (vessel quality, calcification, disease complexity), and (III) surgeon’s experience and preference. Predominantly off-pump surgeons selected on-pump technique primarily when anticipating hemodynamic instability [severely reduced left ventricular function, ejection fraction (EF) <35%] or complex distal anastomoses. Conversely, predominantly on-pump surgeons chose off-pump approach for patients with high CPB risks (severe aortic calcification, renal insufficiency, prior stroke). CABG procedures aimed for complete revascularization of all vessels ≥1.5 mm with ≥70% stenosis, including chronically occluded vessels with suitable distal targets. In off-pump procedures, proximal anastomoses were typically performed using side-bite clamping or HeartString devices (Heartstring Proximal Seal System, Maquet Cardiovascular, Wayne, NJ, USA) depending on aortic conditions. Complete revascularization was defined as performing anastomoses to all epicardial vessels ≥1.5 mm with ≥70% stenosis.

Complete follow-up data was available for 97.3% of patients at median 7.7 years, with vital status for the remaining 2.7% obtained through national health insurance. Follow-up was rigorous during the first 5 years, with mortality data validated through June 2020 using the Asan Biomedical Research Environment system.

Outcomes and definitions

The primary outcome was a composite of all-cause death, spontaneous myocardial infarction (MI), or stroke at 5 years. Major secondary outcomes included the primary endpoint during in-hospital stay and the composite of death, MI, stroke, or repeat revascularization at 5 years. Additional long-term secondary outcomes included individual components of the primary outcome and repeat revascularization.

All outcomes adhered to standard endpoint definitions (10). All-cause mortality was used to provide an unbiased assessment of death. Spontaneous MI was defined as newly developed ischemic symptoms or signs with an increase in cardiac enzyme levels above the upper reference limit, requiring re-hospitalization (emergency admission with a principal diagnosis of MI). Stroke was defined as the sudden onset of a neurological deficit (e.g., vertigo, numbness, aphasia, or dysarthria) caused by vascular brain lesions, including hemorrhage, embolism, thrombosis, or ruptured aneurysm, lasting >24 hours. Repeat revascularization was defined as any repeat percutaneous intervention or surgical bypass of treated or untreated vessels, regardless of clinical or ischemia-driven indications.

Statistical analysis

Statistical analyses were performed to compare long-term outcomes between on-pump and off-pump CABG, including analyses of major clinical subsets. Continuous variables were compared using the Student’s t-test or Wilcoxon rank-sum test, as appropriate, and categorical variables were compared using the χ² test or Fisher’s exact test. Cumulative event curves were estimated using the Kaplan-Meier method and compared with the log-rank test.

For primary analysis, Cox proportional hazard models and inverse probability of treatment weighting (IPTW) were used to compare treatment effects between on-pump and off-pump CABG, adjusting for potential confounders including demographics [age, sex, body mass index (BMI)], comorbidities [diabetes mellitus (DM), hypertension (HTN), hyperlipidemia, smoking status, previous MI, previous percutaneous coronary intervention (PCI), previous heart failure (HF), stroke, chronic kidney disease (CKD), chronic lung disease, atrial fibrillation, peripheral artery disease], clinical presentation, cardiac parameters [EF category, proximal left anterior descending (LAD), left circumflex artery (LCx), right coronary artery (RCA) involvement], procedural factors [completeness of revascularization (CR)], and laboratory findings [hemoglobin, estimated glomerular filtration rate (eGFR)]. Discharge medications [calcium channel blocker (CCB), angiotensin converting enzyme inhibitor/angiotensin II receptor blocker] were also adjusted for in these models. For IPTW analysis, stabilized weights were truncated at the 1st and 99th percentiles.

As a complement to the primary analysis, sensitivity analyses using propensity score (PS) matching were performed to additionally adjust for surgeon type and calendar year of surgery. Among the 11 surgeons who performed operations during the study period, we classified them based on their procedural preferences: off-pump dominant (2 surgeons performing >70% of cases via off-pump), on-pump dominant (2 surgeons performing >70% of cases via on-pump), and neutral (7 surgeons without strong preference for either approach). This classification, along with calendar year of surgery, was included as a covariate to adjust for both surgeon-specific factors and temporal trends in surgical practice. The PS was estimated using a logistic regression model that included the aforementioned covariates. PS matching was performed using a 1:1 nearest neighbor matching with a 0.2-standard deviation caliper. To address surgeon-related confounding, we also compared outcomes between technique-preference concordant patient groups (off-pump CABG by off-pump dominant surgeons versus on-pump CABG by on-pump dominant surgeons). Using the same covariates as in our primary analysis, we applied adjusted Cox regression models to evaluate long-term outcomes in this population.

Pre-specified subgroup analyses were also performed: age group (<65 vs. ≥65 years), sex, BMI (<25 vs. ≥25 kg/m²), major comorbidities (HTN, DM, previous MI, CKD), LV systolic function (<35%, 35–<45%, ≥45%), clinical presentation, and CR. Interaction tests assessed heterogeneity between off-pump treatment and covariates. All P values were two-sided, with values <0.05 considered statistically significant. All statistical analyses were conducted using the R statistical software, version 3.6.3 (R Foundation for Statistical Computing, Vienna, Austria).

Results

Study population and baseline characteristics

We identified 1,410 patients with significant LM CAD who underwent isolated CABG between 2003 and 2017, including 824 (58.4%) off-pump and 586 (41.6%) on-pump procedures. The median follow-up duration was 7.7 years [interquartile range (IQR), 4.3–11.0 years] overall, with 7.3 years (IQR, 3.9–10.9 years) in the off-pump group and 8.4 years (IQR, 5.0–11.9 years) in the on-pump group. During the 15-year study period [2003–2017], the annual CABG volume averaged 277 cases overall and 94 cases for LM CAD. Temporal trends in surgical approaches for both overall CABG and LM cohorts are shown in Figure S1, which demonstrates the overall decline in CABG volume over the study period.

Baseline characteristics and angiographic data are summarized in Table 1. The off-pump group was older, while the on-pump group exhibited higher rates of previous HF and severe LV dysfunction. Clinical presentations at surgery differed between groups; however, anatomical characteristics—including the distribution of diseased vessels, RCA and proximal LAD involvement, as well as anemia prevalence and renal function—were comparable.

Operative characteristics are summarized in Table 2. The off-pump group had a 1.0% conversion rate (8 patients). Five conversions occurred in the predominantly off-pump surgeon group and three in the neutral surgeon group, due to hemodynamic instability (4 cases), difficult vessel exposure (3 cases), and severe adhesions (1 case). All conversions occurred after sternotomy and initial vessel assessment and were analyzed within the off-pump group.

The mean number of total anastomosis sites was lower in the off-pump group (2.9±1.0 vs. 3.2±0.9, P<0.001), which resulted in a lower complete revascularization rate (55.0% vs. 63.8%, P=0.001). Among total anastomoses, arterial anastomoses were fewer (1.9±1.0 vs. 2.1±0.9, P<0.001), whereas venous anastomoses showed no difference between groups (1.1±0.9 vs. 1.1±0.9, P=0.96). Sequential SVG grafting was more frequently performed in the off-pump group (31.7% vs. 24.7%, P=0.003). Temporal changes in multiple versus single arterial grafting and the distribution of arterial and venous conduit selection strategies across the study period are presented in Figure S2.

LAD territory revascularization rates were comparable between groups (99.3%), whereas the off-pump group showed lower rates of LCx (70.8% vs. 77.3%, P=0.01) and RCA territory revascularization (60.6% vs. 68.3%, P=0.01).

Regarding arterial grafting strategy, the off-pump group had equivalent left internal mammary artery (LIMA) use (97.0% vs. 95.7%, P=0.24), although rates of multiple arterial grafting (57.6% vs. 74.1%, P<0.001) and radial artery use (46.7% vs. 71.0%, P<0.001) were lower. Configuration patterns were similar between groups, with bilateral internal mammary arteries predominantly using in situ placement and radial arteries configured as aortocoronary conduits or Y-composite grafts. Despite fewer arterial anastomoses per patient, total arterial revascularization (defined as all grafts being arterial) was achieved more frequently in the off-pump group (33.4% vs. 27.1%, P=0.02).

Discharge medications are shown in Table S1. Aspirin and statin use was universal in both groups, but dual antiplatelet therapy was more frequently prescribed in the off-pump group, while CCB were more common in the on-pump group.

Primary outcome

The primary composite endpoint of death, MI, or stroke occurred in 14.7% of the off-pump group and 15.0% of the on-pump group at 5 years [hazard ratio (HR): 0.98, 95% confidence interval (CI): 0.74–1.30, P=0.88]. This comparable outcome persisted after adjustment using Cox proportional hazards modeling (HR: 0.91, 95% CI: 0.67–1.24, P=0.56) and IPTW analysis (HR: 0.71, 95% CI: 0.46–1.10, P=0.12) (Table 3). Kaplan-Meier analysis demonstrated consistent event rates between groups over the follow-up period (Figure 2A).

Figure 2 Cumulative incidence of major adverse events up to 5 years. Cumulative incidence of (A) death, spontaneous MI, or stroke, and (B) death, spontaneous MI, stroke, or RR at 5 years after off-pump versus on-pump CABG. The 5-year event rates were similar between groups for both the primary outcome (14.7% vs. 15.0%; HR: 0.98, 95% CI: 0.74–1.30; P=0.88) and secondary outcomes (17.1% vs. 17.3%; HR: 1.01, 95% CI: 0.77–1.31; P=0.96). CABG, coronary artery bypass grafting; CI, confidence interval; HR, hazard ratio; MI, myocardial infarction; RR, repeat revascularization.

Secondary outcome

The expanded composite endpoint of death, spontaneous MI, stroke, or repeat revascularization at 5 years showed no significant difference between the off-pump and on-pump groups [17.3% vs. 17.1%; HR: 1.01 (95% CI: 0.77–1.31), P=0.96]. This finding remained consistent across weighted Cox analysis (HR: 0.89, 95% CI: 0.67–1.18, P=0.41) and IPTW analysis (HR: 0.76, 95% CI: 0.50–1.16, P=0.21) (Table 3, Figure 2B).

Analysis of individual components revealed no significant differences in all-cause mortality [12.4% vs. 11.0%; HR: 1.12 (95% CI: 0.81–1.55), P=0.48], stroke rates [2.4% vs. 2.1%; HR: 1.23 (95% CI: 0.58–2.61), P=0.58], or repeat revascularization rates [3.5% each; HR: 0.99 (95% CI: 0.54–1.79), P=0.96] in both unadjusted and adjusted analyses. However, the incidence of spontaneous MI was significantly lower in the off-pump group [1.4% vs. 3.6%; HR: 0.37 (95% CI: 0.17–0.80), P=0.01], with no significant differences in graft occlusion-related MI or repeat revascularization between groups (Table S2). This observed difference in spontaneous MI remained statistically significant in both weighted Cox [HR: 0.25 (95% CI: 0.11–0.54), P<0.001] and IPTW [HR: 0.37 (95% CI: 0.16–0.88), P=0.02] analyses (Table 3, Figure 3A-3D).

Figure 3 Cumulative incidence of individual adverse events up to 5 years. The 5-year event rates were similar between off-pump and on-pump CABG for all-cause mortality (11.0% vs. 12.4%; HR: 1.12, 95% CI: 0.81–1.55; P=0.48) (A), stroke (2.1% vs. 2.4%; HR: 1.23, 95% CI: 0.58–2.61; P=0.58) (C), and repeat revascularization (3.5% vs. 3.5%; HR: 0.99, 95% CI: 0.54–1.79; P=0.96) (D). However, spontaneous MI was significantly lower with off-pump CABG (1.4% vs. 3.6%; HR: 0.37, 95% CI: 0.17–0.80; P=0.01) (B). CABG, coronary artery bypass grafting; CI, confidence interval; HR, hazard ratio; MI, myocardial infarction.

In-hospital outcomes

In-hospital outcomes are summarized in Table 4. The primary composite endpoint of death, perioperative MI, or stroke occurred less frequently in the off-pump group [1.3% vs. 3.5%; HR: 0.37 (95% CI: 0.18–0.78), P=0.01]. Among individual components, in-hospital mortality was significantly lower in the off-pump group [0.8% vs. 2.3%; HR: 0.36 (95% CI: 0.14–0.89), P=0.03], while stroke rates [0.5% vs. 1.5%; HR: 0.32 (95% CI: 0.10–1.04), P=0.06] and repeat revascularization rates [0.4% vs. 0.3%; HR: 1.09 (95% CI: 0.18–6.55), P=0.93] did not differ significantly between the groups.

Subgroup analysis

Prespecified subgroup analyses showed consistent primary composite outcomes across various patient characteristics, including age, sex, body mass index (BMI), cardiovascular risk factors (e.g., hypertension, diabetes, prior MI), renal function, left ventricular function, clinical presentation and completeness of revascularization (Figure 4). No significant interactions between treatment strategy and subgroup characteristics were observed (P for interaction >0.10 for all subgroups).

Figure 4 Subgroup analysis of the primary outcome after off-pump versus on-pump CABG. Event rates, HRs (95% CI), and interaction P values are shown for each subgroup. No significant interactions were observed, suggesting consistent treatment effects across subgroups, although wide confidence intervals in certain subgroups limit precision. BMI, body mass index; CABG, coronary artery bypass grafting; CI, confidence interval; CKD, chronic kidney disease; HR, hazard ratio; LV, left ventricular; MI, myocardial infarction; NSTEMI, non-ST-segment elevation myocardial infarction.

Sensitivity analysis

In a sensitivity analysis using PS matching with additional adjustments for surgeon variability and the calendar year of surgery, the primary outcome of death, MI, or stroke remained comparable between the off-pump and on-pump groups (HR: 0.94, 95% CI: 0.64–1.38, P=0.75). These findings were consistent with those of the primary analysis (Table 3, Figure 5). Analysis of the technique-preference concordant population, after excluding discordant groups with significant baseline imbalances (Table S3), also showed consistent results with no significant difference in the primary composite endpoint (HR: 1.19, 95% CI: 0.82–1.72, P=0.35) (Table S4, Figure S3).

Figure 5 Comparison of off-pump versus on-pump CABG outcomes using different statistical adjustment. Left panel shows anatomical illustration of CABG procedure. Right panel demonstrates cumulative incidence of major adverse cardiovascular events over 5 years (HR: 0.98, 95% CI: 0.74–1.30, P=0.88) and forest plot of hazard ratios using different statistical adjustment methods. CABG, coronary artery bypass grafting; CI, confidence interval; HR, hazard ratio; IPTW, inverse probability of treatment weighting; PS, propensity score.

Extended follow-up data

Ten-year outcomes remained consistent with 5-year results. The primary composite endpoint (death, spontaneous MI, or stroke) was comparable between off-pump and on-pump groups (26.0% vs. 27.6%; HR: 0.95, 95% CI: 0.76–1.19; P=0.66), as was the expanded secondary endpoint (29.5% vs. 30.2%; HR: 0.99, 95% CI: 0.80–1.22; P=0.90) (Table S5, Figure S4). Individual components showed similar rates for mortality, stroke, and repeat revascularization, while the lower incidence of spontaneous MI in the off-pump group persisted (3.1% vs. 5.5%; HR: 0.47, 95% CI: 0.25–0.88; P=0.02) (Table S5, Figure S5).

Discussion

This study evaluated the clinical outcomes of off-pump versus on-pump CABG in patients with significant LM CAD at a single high-volume center. The primary finding was that 5-year composite outcomes (all-cause death, spontaneous MI, or stroke) were comparable between both groups, with the off-pump group showing favorable in-hospital outcomes. Prespecified subgroup analyses demonstrated consistent results across diverse patient characteristics.

CABG remains the standard of care for significant LM CAD (11,12). This patient subset presents technical challenges due to multivessel revascularization requirements. While prior observational studies have included LM CAD patients, they often lacked sufficient sample sizes or dedicated analysis of this subgroup (13,14). Major randomized trials such as Veterans Affairs Randomized On/Off Bypass (ROOBY) and CABG Off or On Pump Revascularization Study (CORONARY), which compared off-pump and on-pump approaches, did not specifically target LM CAD and showed variable results influenced by differing institutional and surgeon expertise (15,16). By focusing specifically on LM CAD patients in a center experienced with both techniques, our study offers insights into the safety and effectiveness of both strategies for this challenging cohort.

Despite concerns about the technical difficulty of performing off-pump CABG in LM CAD, our results demonstrate that experienced surgeons can achieve comparable long-term outcomes (17,18). The primary composite endpoints at both 5 and 10 years showed no significant differences between approaches, consistent across multiple statistical adjustment methods. Prespecified subgroup analyses confirmed these findings across diverse patient characteristics, including patients presenting with acute MI or acute coronary syndrome. Perioperatively, the off-pump approach demonstrated significant advantages, with notably lower in-hospital composite outcomes and mortality. These benefits likely result from avoiding CPB-related complications, reduced aortic manipulation, and less systemic inflammatory response (19). The low conversion rate observed reflects sustained proficiency with the off-pump technique, aligning with recent guidelines that recognize off-pump CABG as a viable alternative, particularly for high-risk populations (1,20). These results suggest that the choice of surgical strategy does not significantly impact long-term outcomes when performed by experienced surgeons.

An interesting finding was the lower incidence of spontaneous MI in the off-pump group that persisted through long-term follow-up. This observation should be interpreted cautiously, considering both physiological effects of avoiding CPB and differences in grafting strategies between groups. While initial physiological benefits of avoiding CPB, such as reduced embolization, less inflammation, and preserved endothelial function, may provide early advantages (21,22), these mechanisms alone cannot fully explain differences persisting years later. Beyond the CPB effect, the distinct grafting strategies employed in each approach may play a crucial role. The increased use of sequential grafting in the off-pump group may have contributed to these findings, potentially providing more efficient revascularization with fewer proximal anastomoses and compensating for lower radial artery utilization (23,24).

CR has traditionally been considered a key goal in CABG, associated with improved long-term outcomes (25). Using strict anatomical criteria requiring grafting of all angiographically significant lesions (26), CR was achieved in 55.0% of off-pump patients and 63.8% of on-pump patients in this study. Interestingly, the off-pump group demonstrated comparable long-term outcomes despite lower CR rates. This finding may reflect the effectiveness of selective revascularization often used in off-pump surgery, prioritizing anatomically critical proximal lesions and regions at higher ischemic risk. For patients with LM CAD, this targeted strategy appears to provide sufficient myocardial protection while minimizing CPB-related risks. Our findings suggest that emphasis on anatomical CR should be balanced against surgical risk and the clinical significance of individual myocardial territories. Rather than focusing solely on the number of grafts performed, the quality of anastomoses and appropriateness of target vessel selection appear to be more critical determinants of clinical outcomes.

Our findings contrast with post-hoc analyses of trials such as Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX), Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization (EXCEL), and German Off-Pump Coronary Artery Bypass Grafting in Elderly Patients (GOPCABE) (27,28), which demonstrated associations between incomplete revascularization and inferior outcomes. This apparent discrepancy may be attributed to several factors, including differences in patient selection, institutional surgical expertise, and approach to target vessel selection that prioritized territories supplying large areas of viable myocardium. However, the complex interplay between surgical technique, patient-specific factors, and revascularization strategies is difficult to fully characterize in single-center studies. Therefore, large-scale, multicenter randomized trials specifically designed to investigate the relationship between revascularization completeness and clinical outcomes in LM CAD patients undergoing off-pump CABG would be valuable to definitively address these questions and guide future clinical practice.

Study limitations

Our study has several key limitations. First, as a retrospective, non-randomized study, our findings are subject to inherent selection bias despite rigorous statistical adjustments. Second, detailed decision-making processes for surgical strategy were not systematically documented, limiting insights into specific off-pump anastomotic techniques. Third, anatomical complexity scores like SYNTAX were unavailable; however, surrogate markers of complexity (coronary artery involvement data) were included. Fourth, graft patency could not be directly evaluated as routine follow-up angiography was not performed. Fifth, despite comprehensive follow-up, events at external institutions may have been missed. Sixth, data on long-term medical management post-discharge medications were not systematically collected. Finally, temporal trends in surgical techniques and variations in individual surgeon expertise may have influenced outcomes despite our statistical adjustment efforts.

Conclusions

This large, single-center study demonstrated that off-pump CABG achieves 5-year clinical outcomes comparable to those achieved with on-pump CABG in patients with significant LM CAD, along with reduced perioperative complications. These findings suggest that off-pump CABG, when performed by experienced surgeons, represents a safe and potentially advantageous strategy for this high-risk patient population. Larger prospective studies are warranted to further validate the long-term safety and efficacy of off-pump CABG in patients with LM CAD.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-634/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-634/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-634/prf

Funding: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. RS-2025-00515862).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-634/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the principles embodied in the Declaration of Helsinki and its subsequent amendments. The study protocol was approved by the Institutional Review Board (IRB) of Asan Medical Center (No. 2020-0413). The requirement for the acquisition of informed consent from patients was waived owing to the retrospective nature of this study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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