Abstract
Aim: The long-term clinical outcomes of endovascular therapy (EVT) for aortoiliac (AI) artery lesions remain unclear. This study aimed to investigate 10-year patency and mortality after AI stent implantation.
Methods: This multicenter retrospective study included 1919 patients (2375 limbs) who underwent AI stent implantation to treat symptomatic peripheral artery disease (PAD) between January 2005 and December 2010. The study outcome was primary patency, which was defined as a treated vessel without restenosis, mortality, and associated factors.
Results: The mean age of the study cohort was 71±9 years. Chronic limb-threatening ischemia (CLTI) accounted for 17.2% of cases, and chronic total occlusion (CTO) was found in 24.6% of cases. During a median follow-up period of 2.9 years (interquartile range: 1.0–6.0 years), 412 patients lost patency, whereas 467 patients died without experiencing loss of patency. At 1, 6, and 10 years post-EVT, respectively, the primary patency rates were estimated to be 92.8%, 79.3%, and 77.2%, and the survival rates were 94.9%, 77.0%, and 63.1%. Female sex, CTO, and the presence of outflow lesions were significantly associated with an increased risk of patency loss after stent implantation (all P＜0.05), whereas age, dialysis-dependent renal failure, heart failure, and CLTI were significantly associated with an increased risk of mortality.
Conclusion: Stent implantation for AI lesions achieved favorable 10-year patency, with patency loss plateauing after six years. No AI lesion characteristic was associated with mortality. These results support the long-term efficacy of EVT in the clinical practice.
Keywords: Endovascular therapy, Aortoiliac artery, Peripheral artery disease, Long-term
Abbreviation list: EVT, endovascular therapy, AI, aortoiliac, PAD, peripheral artery disease, CLTI, chronic limb-threatening ischemia, CTO, chronic total occlusion, CI, confidence interval, FP, femoropopliteal, ABI, ankle-brachial index
Introduction
The number of patients with peripheral artery disease (PAD) is increasing, especially among the aging population 1 - 3) , and these patients have a poor prognosis and a high risk of cardiovascular events 4 - 7) . Endovascular therapy (EVT) with stent implantation for aortoiliac (AI) lesions has become a widely accepted first-line treatment for patients with symptomatic PAD 4 , 5) . In comparison to surgical revascularization, EVT offers a less invasive approach with comparable clinical outcomes, including favorable long-term patency rates, reduced procedural risks, and shorter recovery times. These advantages, combined with its efficacy, safety, and ability to improve the disease prognosis, have firmly established EVT as the preferred treatment in real-world clinical practice 6 , 8 , 9) . Over the years, guideline recommendations have evolved to prioritize EVT for AI lesions, supported by accumulating evidence of its mid- and long-term efficacy. However, few studies have explored clinical outcomes beyond 5 years, especially in large-scale settings. The REAL-AI study reported favorable mid-term outcomes after AI stenting 8) . To address long-term data gaps, this study evaluated the 10-year clinical outcomes from the REAL-AI registry, focusing on long-term patency, mortality, and associated prognostic factors in patients undergoing AI stenting for symptomatic PAD.
Methods
Study Population
We retrospectively analyzed a multicenter clinical database of the REtrospective multicenter AnaLysis of Aorto-iliac stenting (REAL-AI) registry 8) , which included 1924 patients (2380 limbs) who underwent stent implantation for symptomatic de novo AI artery disease across 16 cardiovascular centers in Japan between January 2005 and December 2010. Of these, five cases were excluded because of missing baseline characteristics. The remaining 1919 patients (2375 limbs) were included in the current study. The study was conducted in accordance with the Declaration of Helsinki and approved by the institutional review boards of the participating institutions. The requirement for informed consent was waived. This study was registered with the University Hospital Medical Information Network-Clinical Trials Registry (UMIN-CTR), as accepted by the International Committee of Medical Journal Editors (No. UMIN000006032). The original study design allowed retrospective data collection without a predefined follow-up period. In this study, 10-year follow-up data were included. To ensure ethical oversight, additional approval was obtained from the respective institutional review boards in compliance with current standards for handling personal data.
Outcome Measures
Censoring was defined as the absence of events owing to loss to follow-up, transfer to another hospital, or survival without events by the end of the study period (December 31, 2020).
The primary outcome measure of this study was primary patency, and the secondary outcome measures were freedom from reintervention, occlusion, bypass conversion of the target lesion, and mortality. Primary patency was defined as the treated vessel without restenosis. Restenosis was defined as a peak systolic velocity ratio ＞2.4 on duplex ultrasound, stenosis ＞50% on angiography or computed tomography, or a 0.2 decrease in resting ankle-brachial index (ABI). Freedom from target lesion revascularization (TLR) is an important indicator of the effectiveness of EVT; however, due to challenges in long-term follow-up (＞10 years), primary patency was adopted as a standardized measure. Outflow vessels and calcification were assessed using angiography before and after the procedure. Outflow lesions were considered present when the common femoral or femoropopliteal artery had ＞50% stenosis, or when one or two poor infrapopliteal runoffs were observed. The secondary outcome measures were freedom from re-intervention, occlusion, bypass conversion, and mortality.
Heart failure was defined as a history of treatment for heart failure with a preserved ejection fraction (HFpEF) or reduced ejection fraction (HFrEF). Dual antiplatelet therapy (DAPT) was defined as the administration of aspirin (100 mg/day), clopidogrel (75 mg/day), or ticlopidine (100 mg, twice daily).
Statistical Analyses
Data are presented as the mean and standard deviation for continuous variables or as the percentage for discrete variables, unless otherwise mentioned. Statistical significance was set at P＜0.05, and 95% confidence intervals (CIs) were reported where appropriate. Primary patency and freedom from re-intervention, occlusion, and bypass conversion were estimated using the cumulative incidence function, treating death as a competing risk. The association between baseline characteristics and loss of patency was analyzed using Fine and Gray’s regression model for the subdistribution of competing risks. The proportional hazards assumption regarding each variable of interest was verified by developing a model in which the variable and its interaction term with time were simultaneously included. When the null hypothesis, that the regression coefficient of the interaction term with time was zero, was statistically rejected, indicating that the proportional hazards assumption was violated, the interaction term with time was included in the subsequent multivariate model. Additionally, we estimated the overall survival rate using the Kaplan–Meier method and investigated the association between baseline characteristics and mortality risk using the Cox regression model. All statistical analyses were performed using R (ver. 3.6.0, R Development Core Team, Vienna, Austria).
All-cause mortality was defined as mortality throughout the analysis. The number of deaths without a loss of patency refers to the number of patients who died before restenosis.
Results
The baseline characteristics of the study population are shown in Table 1 . The mean age was 71±9 years, and the proportions of patients who were female and who were currently smoking, had diabetes mellitus, and had dialysis-dependent renal failure were 18.3%, 37.8%, 48.0%, 16.3%, and 12.0%, respectively. Chronic limb-threatening ischemia (CLTI) accounted for 17.2% of all limbs analyzed. Chronic total occlusion (CTO) was found in 24.6% of the limbs, and the mean lesion length was 55±41 mm. Outflow lesions were observed in 37.6% of cases, and self-expandable stents were used in 68.1% of cases.
Table 1. Baseline characteristics of the study population.
| Patient characteristics | (n = 1919) |
| Female sex | 351 (18.3%) |
| Age (years) | 71±9 |
| Current smoking | 725 (37.8%) |
| Diabetes mellitus | 921 (48.0%) |
| Dialysis dependence | 312 (16.3%) |
| Heart failure＊1 | 231 (12.0%) |
| Dual antiplatelet therapy＊2 | 834 (43.5%) |
| Cilostazol use | 843 (43.9%) |
| Statin use | 723 (37.7%) |
| Limb characteristics | (n = 2375) |
| Chronic limb-threatening ischemia | 409 (17.2%) |
| TASC II classification | |
| Class A | 1086 (45.7%) |
| Class B | 628 (26.4%) |
| Class C | 286 (12.0%) |
| Class D | 375 (15.8%) |
| Chronic total occlusion | 585 (24.6%) |
| Calcification | 1219 (51.3%) |
| Lesion length (mm) | 55±41 |
| Reference vessel diameter (mm) | 8.1±2.3 |
| Aorta-to-bifurcation lesion | 257 (10.8%) |
| CFA lesion | 117 (4.9%) |
| Outflow lesion | 892 (37.6%) |
| Self-expandable stent | 1617 (68.1%) |
Heart failure: Defined as patients with a history of treatment for heart failure with preserved ejection fraction (HFpEF) or heart failure with a reduced ejection fraction (HFrEF).
Dual antiplatelet therapy (DAPT): Defined as the use of aspirin (100 mg/day) plus clopidogrel (75 mg/day) or ticlopidine (100 mg twice a day). TASCII,
Trans-Atlantic Inter-Society Consensus
CFA, common femoral artery
Data are given as n (%) or the mean±SD.
During a median follow-up of 2.9 years (interquartile range: 1.0–6.0 years), 412 patients lost patency, whereas 467 patients died without experiencing loss of patency. Notably, no restenosis cases were determined solely on the basis of a reduced ABI. In all cases where restenosis was judged, imaging assessments, such as angiography, duplex ultrasound, or computed tomography, were performed to validate the findings. The follow-up rates were 89.6% at 1 year, 71.5% at 3 years, 58.9% at 5 years, and 48.0% at 10 years. The primary patency (95% CI) rates were estimated to be 92.8% (91.7%–93.9%) at 1 year, 79.3% at 6 years, and 77.2% at 10 years ( Fig.1 ) . The rates of freedom from reintervention and occlusion were estimated to be 96.8% and 99.1%, respectively, at 1 year; 90.1% and 98.7% at 6 years; and 88.4% and 98.7% at 10 years.
Fig.1. Limb outcomes after aortoiliac stent implantation.
The incidence rate was estimated using the cumulative incidence function, in which death was treated as a competing risk. Dotted lines indicate the 95% confidence intervals. SE, standard error.
Notably, the median follow-up duration (2.9 years) reflects the nature of retrospective studies, where follow-up was not mandatory. Hence, many patients were censored early, and the median follow-up appeared short, despite a substantial subset being followed for up to 10 years. This is consistent with the decreasing number of at-risk patients over time, as shown in the Kaplan–Meier plots. Supplementary Fig.1 shows the cumulative number of observed events, competing risk events, and censored cases for (A) freedom from restenosis, (B) freedom from reintervention, and (C) freedom from occlusion.
Supplementary Fig.1.
Cumulative number of observed events, competing risk events and censored cases, stratified by (A) freedom from restenosis, (B) freedom from reintervention, and (C) freedom from occlusion
As shown in Table 2 , CLTI and CTO demonstrated a significant interaction effect with time in the respective crude models (all P＜0.05), indicating that the assumption of proportional hazards was violated regarding these variables. Therefore, we subsequently developed a multivariate model in which these variables accompanied their interaction terms with time, whereas the other variables did not. Consequently, as summarized in Table 3 , female sex, CTO, and the presence of outflow lesions were significantly associated with an increased risk of patency loss immediately after stent implantation (all P＜0.05), and the prognostic impact of CTO was significantly attenuated afterward (P＜0.05). Fig.2 presents the cumulative incidence function curves stratified by sex, CTO, and outflow disease status.
Table 2. Change in the impact of the baseline characteristics on the risk of patency loss during the follow-up period.
| Fold change of hazard ratio per doubling of the follow-up time | |
|---|---|
| Female sex | 0.92 [0.82–1.03] (P = 0.13) |
| Age (years) | 1.00 [0.99–1.00] (P = 0.11) |
| Current smoking | 0.95 [0.86–1.06] (P = 0.36) |
| Diabetes mellitus | 1.00 [0.90–1.10] (P = 0.94) |
| Dialysis dependence | 0.97 [0.86–1.10] (P = 0.66) |
| Heart failure | 0.99 [0.84–1.16] (P = 0.86) |
| Dual antiplatelet therapy | 1.04 [0.93–1.15] (P = 0.51) |
| Cilostazol use | 1.01 [0.91–1.12] (P = 0.81) |
| Statin use | 1.10 [0.98–1.23] (P = 0.11) |
| Chronic limb-threatening ischemia | 0.88 [0.78–1.00] (P = 0.046) |
| Chronic total occlusion | 0.87 [0.78–0.98] (P = 0.018) |
| Calcification | 0.93 [0.83–1.03] (P = 0.18) |
| Lesion length (mm) | 1.00 [1.00–1.00] (P = 0.061) |
| Reference vessel diameter (mm) | 1.02 [0.98–1.07] (P = 0.38) |
| Aorta-to-bifurcation lesion | 1.00 [0.86–1.15] (P = 0.96) |
| CFA lesion | 0.91 [0.77–1.08] (P = 0.27) |
| Outflow lesion | 0.97 [0.88–1.08] (P = 0.61) |
| Self-expandable stent | 0.97 [0.87–1.08] (P = 0.60) |
CFA, common femoral artery
Data are presented as the fold change in the hazard ratio of each variable per doubling of the follow-up time [95% confidence intervals] (P values), derived from Fine and Gray’s regression model for the sub-distribution of competing risks in which all variables of interests and their interaction term with time were entered as explanatory variables. The fold changes in the hazard ratio by time were calculated as the exponential conversion of the regression coefficient for the interaction term with time.
Table 3. Impact of the baseline characteristics on the risk of patency loss.
| Adjusted hazard ratio | |
|---|---|
| Female sex | 1.40 [1.10–1.78] (P = 0.005) |
| Age (years) | 0.99 [0.98–1.00] (P = 0.097) |
| Current smoking | 0.97 [0.79–1.20] (P = 0.79) |
| Diabetes mellitus | 1.18 [0.97–1.44] (P = 0.094) |
| Dialysis dependence | 1.15 [0.87–1.51] (P = 0.32) |
| Heart failure | 0.79 [0.58–1.09] (P = 0.15) |
| Dual antiplatelet therapy | 1.15 [0.92–1.43] (P = 0.21) |
| Cilostazol use | 0.90 [0.72–1.12] (P = 0.36) |
| Statin use | 1.00 [0.82–1.23] (P = 0.98) |
| Chronic limb-threatening ischemia | 2.13 [0.73–6.19] (P = 0.17) |
| Interaction with time | 0.89 [0.79–1.01] (P = 0.066) |
| Chronic total occlusion | 3.55 [1.31–9.58] (P = 0.013) |
| Interaction with time | 0.88 [0.79–0.99] (P = 0.033) |
| Calcification | 1.05 [0.85–1.29] (P = 0.67) |
| Lesion length (mm) | 1.00 [1.00–1.00] (P = 0.44) |
| Reference vessel diameter (mm) | 0.94 [0.87–1.02] (P = 0.15) |
| Aorta-to-bifurcation lesion | 1.32 [0.99–1.76] (P = 0.057) |
| CFA lesion | 1.08 [0.71–1.64] (P = 0.73) |
| Outflow lesion | 1.76 [1.42–2.18] (P＜0.001) |
| Self-expandable stent | 0.95 [0.76 to 1.18] (P = 0.63) |
CFA, common femoral artery
Data are presented as adjusted hazard ratios for loss of patency and their 95% confidence intervals, derived from Fine and Gray’s regression model for the sub-distribution of competing risks. Unadjusted hazard ratios were obtained from the models in which all variables of interest (and their interaction with time) were entered as explanatory variables, whereas adjusted hazard ratios were from the model in which all variables listed in the table were entered. Data on the interaction with time are presented as the fold change in the hazard ratio of each variable per doubling of the follow-up time.
Fig.2. Cumulative incidence function curves for patency loss, stratified by (A) female sex, (B) presence of chronic total occlusion (CTO), and (C) outflow disease.
These plots visually demonstrate subgroup differences in patency over time.
Fig.3 shows the Kaplan–Meier estimates of the overall survival rate. The survival rates (95% confidence interval [CI]) were estimated to be 94.9% at 1 year, 87.6% at 3 years, 77.0% at 6 years, and 63.1% at 10 years. Female sex, CLTI, CTO, arterial calcification, lesion length, reference vessel diameter, and presence of outflow lesions demonstrated a significant interaction effect with time in the respective crude models (all P＜0.05) ( Table 4 ) . The subsequent multivariate Cox regression model demonstrated that age, dialysis-dependent renal failure, heart failure, and CLTI were significantly associated with an increased risk of mortality immediately after stent implantation (all P＜0.05) ( Table 5 ) , and the prognostic impact of CLTI was significantly attenuated afterward (P = 0.002). Fig.4 shows Kaplan–Meier survival curves of high-risk and low-risk groups (e.g., dialysis, heart failure, and CLTI).
Fig.3. Overall survival rate after aortoiliac stent implantation.
The rate was estimated using the Kaplan–Meier method. Dotted lines indicate 95% confidence intervals. SE, standard error.
Table 4. Change in the impact of the baseline characteristics on the risk of mortality during the follow-up period.
| Fold change of hazard ratio per doubling of the follow-up time | |
|---|---|
| Female sex | 0.89 [0.81–0.98] (P = 0.023) |
| Age (years) | 1.00 [0.99–1.00] (P = 0.94) |
| Current smoking | 1.06 [0.97–1.17] (P = 0.21) |
| Diabetes mellitus | 1.00 [0.92–1.09] (P = 0.99) |
| Dialysis dependence | 1.00 [0.91–1.10] (P = 0.97) |
| Heart failure | 0.95 [0.86–1.05] (P = 0.28) |
| Dual antiplatelet therapy | 1.08 [0.98–1.18] (P = 0.10) |
| Cilostazol use | 0.98 [0.90–1.07] (P = 0.66) |
| Statin use | 1.07 [0.97–1.18] (P = 0.17) |
| Chronic limb-threatening ischemia | 0.79 [0.71–0.88] (P＜0.001) |
| Chronic total occlusion | 0.90 [0.82–0.99] (P = 0.027) |
| Calcification | 0.91 [0.82–1.00] (P = 0.045) |
| Lesion length (mm) | 1.00 [1.00–1.00] (P = 0.043) |
| Reference vessel diameter (mm) | 1.05 [1.01–1.09] (P = 0.014) |
| Aorta-to-bifurcation lesion | 0.92 [0.81–1.03] (P = 0.15) |
| CFA lesion | 0.94 [0.82–1.08] (P = 0.37) |
| Outflow lesion | 0.88 [0.80–0.97] (P = 0.009) |
| Self-expandable stent | 0.93 [0.84–1.03] (P = 0.14) |
CFA, common femoral artery
Data are presented as the fold change in the hazard ratio of each variable per doubling of the follow-up time [95% confidence interval] (P values), derived from the Cox regression model in which all variables of interest their interaction term with time were entered as the explanatory variables. The fold changes in the hazard ratio by time were calculated as the exponential conversion of the regression coefficient for the interaction term with time.
Table 5. Impact of the baseline characteristics on the risk of mortality.
| Adjusted hazard ratio | |
|---|---|
| Female sex | 1.81 [0.69–4.79] (P = 0.23) |
| Interaction with time | 0.92 [0.84–1.02] (P = 0.12) |
| Age (years) | 1.05 [1.04–1.06] (P＜0.001) |
| Current smoking | 0.87 [0.71–1.07] (P = 0.19) |
| Diabetes mellitus | 1.00 [0.83–1.22] (P = 0.97) |
| Dialysis dependence | 2.79 [2.20–3.55] (P＜0.001) |
| Heart failure | 1.61 [1.25–2.07] (P＜0.001) |
| Dual antiplatelet therapy | 0.95 [0.77–1.17] (P = 0.63) |
| Cilostazol use | 0.90 [0.73–1.11] (P = 0.32) |
| Statin use | 0.84 [0.68–1.03] (P = 0.088) |
| Chronic limb-threatening ischemia | 10.5 [3.44–32.2] (P＜0.001) |
| Interaction with time | 0.83 [0.74–0.93] (P = 0.002) |
| Chronic total occlusion | 1.57 [0.56–4.40] (P = 0.39) |
| Interaction with time | 0.95 [0.85–1.05] (P = 0.33) |
| Calcification | 1.48 [0.56–3.91] (P = 0.43) |
| Interaction with time | 0.98 [0.89–1.08] (P = 0.69) |
| Lesion length (mm) | 1.00 [0.99–1.01] (P = 0.41) |
| Interaction with time | 1.00 [1.00–1.00] (P = 0.37) |
| Reference vessel diameter (mm) | 0.73 [0.50–1.04] (P = 0.082) |
| Interaction with time | 1.02 [0.99–1.06] (P = 0.24) |
| Aorta-to-bifurcation lesion | 1.24 [0.91–1.70] (P = 0.17) |
| CFA lesion | 1.18 [0.80–1.74] (P = 0.40) |
| Outflow lesion | 1.73 [0.63–4.71] (P = 0.29) |
| Interaction with time | 0.98 [0.89–1.08] (P = 0.66) |
CFA, common femoral artery
Data are presented as adjusted hazard ratios for mortality and their 95% confidence intervals, derived from the Cox regression model. Unadjusted hazard ratios were obtained from the models in which all variables of interest (and their interaction with time) were entered as explanatory variables, whereas adjusted hazard ratios were from the model in which all variables listed in the table were entered. Data on the interaction with time are presented as the fold change in the hazard ratio of each variable per doubling of the follow-up time.
Fig.4. Kaplan–Meier survival curves for mortality, stratified by (A) dialysis dependence, (B) heart failure, and (C) chronic limb-threatening ischemia (CLTI).
These plots illustrate differences in long-term survival across high-risk and low-risk subgroups.
Discussion
This study evaluated the long-term outcomes and prognostic factors of patients undergoing stent implantation for de novo AI lesions. Previous studies have reported a 5-year patency rate of 64%–77% after AI stent implantation 4 , 8) , which was considerably better than the rate after stent implantation for femoropopliteal (FP) lesions 4 , 5 , 10 , 11) . This study presented patency data from additional follow-up over a longer duration. A 10-year follow-up study on stent implantation for FP lesions 11) showed that vessel patency was continuously reduced after one year, even up to 10 years. On the other hand, in our study, the primary patency rates at 1, 6, and 10 years were estimated to be 92.8%, 79.3%, and 77.2%, respectively, indicating that the loss of primary patency plateaued 6 years after stent implantation. The inclusion and analysis of long-term data validated the effectiveness of EVT in patients with PAD.
The patency rates after surgical revascularization and aortobifemoral bypass in claudicant and CLTI patients were 91% and 87.5%, respectively, at 5 years, and 86% and 81% at 10 years 12) . Our study showed that primary patency 10 years after EVT was comparable to that observed after surgical revascularization. Moreover, in our study, the rates of freedom from reintervention, occlusion, and bypass conversion after EVT were estimated to be 90.5%, 98.7%, and 98.6%, respectively, at 5 years, and 88.%, 98.7%, and 98.6% at 10 years. These favorable long-term results justify the use of EVT as the first-line treatment for AI lesions in real-world clinical practice.
In our study, the risk factors for restenosis after AI stent implantation were female sex, CTO, and presence of outflow lesions. However, CTO influenced restenosis in the short-term, whereas female sex and the presence of outflow lesions had a continuous influence. Restenosis of AI lesions may occur without a decline in ABI or symptom recurrence, potentially leading to underestimation of the restenosis rate. Furthermore, the presence of outflow lesions might further contribute to the risk of restenosis in AI lesions, as FP lesions are more likely to present with ABI decline or symptom recurrence, making the concurrent detection of AI restenosis more likely. The negative impact of female sex on the mid-term outcomes of EVT for iliac lesions has been reported previously 8 , 13 , 14) . Our results expanded this to show that female sex negatively affects the long-term outcomes after EVT. AI lesions are often contiguous and extend into the common femoral artery. All treatments in this study were endovascular, and appropriate hybrid treatments might have improved the outcomes.
Similar to other studies 8 , 15) , the nature and number of antiplatelet agents at baseline did not influence long-term primary patency after AI stent implantation. However, our data on medication were only for the baseline period, and no changes in the follow-up period were recorded. As discontinuation of antiplatelet therapy is an independent predictor of long-term primary patency 16) , we would have provided a more detailed evaluation if there were further data on medication in our study.
In our study, the risk factors for mortality after AI stent implantation were age, dialysis-dependent renal failure, heart failure, and CLTI. The prognostic impact of CLTI was limited to the short term and significantly attenuated afterward. The influence of CLTI on mortality may be affected by the poor prognosis of patients with CLTI 4 , 5 , 17) . Unlike FP lesions, AI lesion characteristics did not contribute to mortality after AI stent implantation 11) . Renal failure, especially dialysis-dependent failure, has proven to be a strong independent predictor of cardiovascular disease and mortality 18 , 19) . These results suggest that management of the patient’s background and cardiovascular disease is important for improving the prognosis after the treatment of AI lesions.
Limitations
The present study was associated with several limitations. First, this analysis was retrospective and nonrandomized despite being a multicenter, high-volume study. Second, the assessment for restenosis was not conducted under a core laboratory review. Duplex ultrasound of the aortoiliac arteries, especially the common iliac arteries, is often difficult to perform because of anatomical constraints and may have underestimated stent patency rates. Third, this study did not include data on the frequency of intravascular ultrasound (IVUS) use during the initial treatment of AI lesions. Although there are varying reports on the impact of IVUS on the outcomes of AI lesions, its potential influence on the results cannot be ruled out. This limitation should be considered when interpreting the findings of this study. Fourth, the median follow-up period of 2.9 years reflects the retrospective nature of the study and the challenges of maintaining long-term follow-up, including patient mortality and dropout. This limitation may have influenced the robustness of the 10-year outcome assessment. Fifth, the present subjects were all Japanese; therefore, the results might have an ethnic bias. Additionally, data on antiplatelet therapy were limited to the initial treatment period and no follow-up prescription data were collected. This may have influenced the interpretation of its impact on the long-term patency. Sixth, covered stent implantation and the use of factor Xa antagonists were not included in this study because they were unavailable at the time of treatment. Recent reports have shown that the use of covered stents for complex AI lesions and factor Xa antagonists for patients with PAD had favorable outcomes20, 21), These parameters may further improve patency in patients after EVT. Finally, patients who were successfully followed for 10 year might represent a selected subgroup with a better prognosis. This may have introduced a selection bias and limited the generalizability of the 10-year outcomes.
Conclusion
Stent implantation for de novo AI lesions demonstrated favorable patency outcomes for as long as 10 years, justifying its use in real-world settings. Predictors of primary patency included female sex, CTO, and the presence of outflow lesions, whereas mortality was influenced by age, dialysis-dependent renal failure, heart failure, and CLTI. Importantly, no AI lesion characteristics were associated with mortality.
Perspectives
WHAT IS KNOWN? While the safety and good mid-term clinical outcomes established of EVT managed AI stent implantation have been reported by many studies, the long-term clinical outcomes remain to be elucidated.
WHAT IS NEW? Our large-scale and very long-term study results demonstrated the efficacy of EVT more firmly. The 10-year patency after stent implantation for AI lesions was favorable, and patency loss almost plateaued at 6 years post-EVT. Furthermore, no characteristics of AI lesions affected mortality.
WHAT IS NEXT? EVT with AI stent implantation is now the most widely accepted first-line treatment for symptomatic patients with PAD. Managing patients with PAD according to background may improve their life span and QOL.
Acknowledgments
The authors would like to thank the cardiac catheterization laboratory medical staff and clinical research coordinators of the participating centers.
Financial Support
None.
Conflict of Interest
None of the authors has a real or perceived conflict of interest regarding the work in the manuscript.
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