Abstract
Background
Aorto‐ostial chronic total occlusions (CTOs) of the right coronary artery (RCA) represent a particularly complex subset of CTO percutaneous coronary interventions (PCI), yet dedicated data remain limited. We aimed to evaluate technical outcomes of aorto‐ostial versus non–aorto‐ostial RCA CTO PCI and to identify predictors of failure in RCA aorto‐ostial lesions.
Methods
Patients undergoing RCA CTO PCI between 2016 and 2024 and enrolled in the ERCTO (European Registry of Chronic Total Occlusion) registry were included in the present analysis. The primary end point was technical success. Multivariable logistic regression was used to identify independent predictors of technical failure.
Results
A total of 26 374 patients undergoing RCA CTO PCI were included in the analysis, of whom 2850 had aorto‐ostial and 23 524 non–aorto‐ostial lesions. Technical success was lower in aorto‐ostial compared with non–aorto‐ostial lesions (79.6% versus 89.7%; P<0.001). Aorto‐ostial location was independently associated with technical failure (adjusted odds ratio [OR], 1.85; P<0.001). In multivariable analysis restricted to aorto‐ostial CTOs, stumpless proximal cap morphology (adjusted OR, 2.44, P<0.001), moderate‐to‐severe tortuosity (adjusted OR, 2.13 P<0.001), severe calcification (adjusted OR, 1.92, P<0.001), and peripheral artery disease (adjusted OR, 1.57 P<0.001) were independently associated with technical failure. In‐hospital major adverse cardiac and cerebrovascular events rates were low and did not differ significantly between groups.
Conclusions
Aorto‐ostial RCA CTO PCI has a significantly lower technical success despite extensive use of advanced techniques. Technical failure is driven primarily by lesion‐specific anatomical features, underscoring the need for dedicated strategies and refined risk stratification tailored to aorto‐ostial anatomy.
Keywords: coronary disease, CTO, PCI, RCA
Subject Categories: Percutaneous Coronary Intervention
Nonstandard Abbreviations and Acronyms
- CTO
chronic total occlusion
- ERCTO
European Registry of Chronic Total Occlusion
- J‐CTO
Japanese Chronic Total Occlusion Score
- MACCE
major adverse cardiac and cerebrovascular events
- TVR
target‐vessel revascularization
Clinical Perspective.
What Is New?
This study provides the largest dedicated evaluation of aorto‐ostial right coronary artery chronic total occlusions to date, demonstrating that these lesions account for 10.8% of all right coronary artery chronic total occlusions and are associated with significantly lower technical success compared with non–aorto‐ostial right coronary artery chronic total occlusions (79.6% versus 89.7%; P<0.001), despite more frequent use of advanced procedural techniques.
Technical failure in aorto‐ostial right coronary artery chronic total occlusions was primarily associated with lesion‐specific anatomical features (absence of stump, proximal cap morphology, moderate‐to‐severe calcification, and moderate‐to‐severe tortuosity) with peripheral artery disease as the only clinical variable independently associated with failure.
What Are the Clinical Implications?
These findings underscore the importance of careful preprocedural planning, early consideration of retrograde strategies, and referral to experienced centers for aorto‐ostial right coronary artery chronic total occlusions and highlight the need for dedicated risk stratification tools tailored to the unique anatomical challenges of this lesion subset.
Percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) remains one of the most technically demanding procedures in interventional cardiology. Nevertheless, due to the refinement of dedicated techniques and devices, the adoption of standardized algorithms, and increased operator experience, success rates have improved substantially, reaching >85% to 90% in expert hands and high‐volume centers. 1 , 2 , 3
Despite these advances, CTO PCI outcomes remain strongly influenced by lesion and procedural complexity. 4 , 5 , 6 , 7 Among the most challenging scenarios are aorto‐ostial CTOs, which are most commonly located in the right coronary artery (RCA). 8 Indeed, aorto‐ostial CTOs present distinct anatomical and technical challenges, including ambiguous or stumpless proximal cap flush with the aortic wall, poor coaxial guide catheter engagement, and limited antegrade crossing options—often necessitating a retrograde approach. 9
However, data specifically focusing on this lesion subset remain limited and aorto‐ostial RCA CTOs are poorly captured by widely used scores such as the Japanese Chronic Total Occlusion Score (J‐CTO) and PROGRESS‐CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) scores, which were not specifically designed to account for the anatomical constraints of aorto‐ostial CTOs. 10 , 11 The aim of this study was to evaluate technical outcomes, procedural strategies, and predictors of technical failure in patients undergoing PCI for aorto‐ostial RCA CTOs, and to compare these outcomes with non–aorto‐ostial RCA CTO lesions.
METHODS
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Study Population
This study is a retrospective observational analysis of the ERCTO (European Registry of Chronic Total Occlusion), a multicenter database supported by the European CTO Club. The registry enrolls consecutive patients undergoing CTO PCI performed by experienced operators across high‐volume centers in Europe and Turkey. For the present analysis all patients undergoing RCA CTO PCI between January 1, 2016, and December 31, 2024, were included. In cases with multiple CTOs, only the RCA occlusion was considered. Procedural strategy and device selection were left at the discretion of the operator. For the present analysis, patients were required to have complete information on the primary end point (technical success), resulting in exclusion of procedures with missing angiographic outcome adjudication. In‐hospital clinical outcomes, including major adverse cardiac and cerebrovascular events (MACCE) and procedural events, were evaluated exclusively in procedures with available follow‐up data within the registry.
Ethical Approval
This study is a retrospective analysis of the ERCTO registry, which was approved by the institutional review boards or ethics committees of all participating centers in accordance with national regulations. As this was a retrospective registry study, written informed consent was waived per institutional protocols. The registry was conducted in accordance with the principles of the Declaration of Helsinki and international data protection standards. The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors' institutions and Food and Drug Administration guidelines, including patient consent where appropriate.
Definitions
CTO was defined as a native coronary occlusion with thrombolysis in myocardial infarction 0 flow and a presumed or documented duration exceeding 3 months. Aorto‐ostial RCA CTO was defined as an occlusion originating within the proximal 5 mm of the RCA ostium, including flush occlusions without a proximal stump; lesions arising distal to this segment were classified as non–aorto‐ostial. Angiographic and lesion characteristics were assessed according to the ERCTO data dictionary. Calcifications, assessed semiquantitatively using angiography and consistent with previous studies, were graded as mild when limited to spotty radiopacities, moderate when radiopacities involved a single arterial wall during the cardiac cycle, and severe when radiopacities were visible without cardiac motion, typically involving both arterial walls. Tortuosity, occlusion length, stump morphology, distal vessel quality, collateral grade, and collateral filling pattern were systematically recorded. Bifurcation involvement was defined by the presence of a side branch at least 2 mm in diameter within 5 mm of either the proximal or distal cap. 12 Crossing strategies were assigned based on the method ultimately resulting in distal true lumen entry and were adjudicated according to the Chronic Total Occlusion Academic Research Consortium classification. 13 , 14
Technical success was defined as <30% residual stenosis with thrombolysis in myocardial infarction 3 flow in the target vessel at procedure completion. MACCE were defined as a composite of all‐cause death, myocardial infarction, stroke, urgent target‐vessel revascularization with PCI or coronary artery bypass grafting, or cardiac tamponade requiring pericardiocentesis or surgical intervention. Myocardial infarction was defined according to the Fourth Universal Definition of Myocardial Infarction. MACCE events were captured if they occurred periprocedurally or during the index hospitalization, when follow‐up data were available.
Outcomes
The primary end point of the study was technical success. The primary analytical objective was to identify independent predictors of technical failure within the subgroup of aorto‐ostial occlusions. Secondary end points included the incidence of in‐hospital MACCE and individual adverse events.
Statistical Analysis
Continuous variables are expressed as mean±SD or median with interquartile range, depending on distribution, and were compared using the Student t‐test or the Mann–Whitney U test. Categorical variables are presented as counts and percentages based on available‐case denominators and were compared using the χ 2 test or Fisher's exact test when appropriate.
Multivariable logistic regression was used to identify independent predictors of technical failure. All clinical and angiographical relevant variables, consistent with contemporary CTO literature and found to be significant in the univariable analysis (P<0.10) were included in the multivariable model. Two prespecified multivariable logistic regression models were constructed. The first model was applied to the overall cohort with RCA CTO and included aorto‐ostial location alongside clinical and angiographic variables significant in univariable analysis (P<0.10). The second model was restricted to the aorto‐ostial subgroup and included a separate set of covariates selected based on univariable significance within this subset. Formal interaction testing between lesion location and individual predictors was not performed, as the subgroup‐specific model was designed to identify factors independently associated with failure within aorto‐ostial CTOs. Anatomical predictors were dichotomized according to established thresholds: stumpless versus any stump, moderate‐to‐severe versus straight‐to‐slight tortuosity, and moderate–severe versus none–mild calcification. Categorical predictors with >2 levels were otherwise incorporated using indicator variables. Secondary analyses compared procedural success and MACCE between aorto‐ostial and non–aorto‐ostial lesions and evaluated the distribution of final crossing strategies as a procedural characteristic. No adjustment for multiple comparisons was applied to secondary analyses, given their exploratory nature and the prespecified hierarchy of end points. A 2‐sided P value <0.05 was considered statistically significant. All analyses were performed using R version 4.3.3 (R Foundation for Statistical Computing, Vienna, Austria).
RESULTS
Study Population
A total of 49 228 CTO PCI procedures were included in the ERCTO registry between January 2016 and December 2024. After the exclusion of 22 647 patients without an RCA CTO, 26 581 patients who underwent RCA CTO PCI were identified. Among these, 207 procedures lacked essential variables required for adjudication of technical success and were excluded from the primary end point analysis, yielding a final analytic cohort of 26 374 patients. Of these, 2850 (10.8%) had an aorto‐ostial RCA CTO and 23 524 (89.2%) had non–aorto‐ostial lesions (Figure 1).
Figure 1. Study flow chart.
CTO indicates chronic total occlusion; ERCTO, European Registry of Chronic Total Occlusion; and RCA, right coronary artery.
Baseline, Lesion, and Procedural Characteristics
Baseline characteristics of the study population are shown in Table 1. Patients with aorto‐ostial lesions were slightly older (65.7±10.6 versus 64.4±10.3 years; P<0.001) and more frequently had hypertension (80.1% versus 76.2%; P<0.001) and peripheral artery disease (15.9% versus 11.4%; P<0.001). Prior coronary artery bypass grafting (14.9% versus 12.3%; P<0.001) and prior PCI (54.9% versus 51.0%; P<0.001) were also more common in the aorto‐ostial group. The distribution of left ventricular ejection fraction categories did not differ significantly between groups.
Table 1.
Clinical Characteristics of Patients Undergoing RCA CTO PCI According to Aorto‐Ostial Versus Non–Aorto‐Ostial Lesion Location
| Patient characteristics | Non–aorto‐ostial RCA CTO (n=23 524) | Aorto‐ostial RCA CTO (n=2850) | P value |
|---|---|---|---|
| Age, y | 64.4±10.3 | 65.7±10.6 | <0.001 |
| Male sex | 20 257 (84.2) | 1856 (80.5) | <0.001 |
| Body mass index, kg/m2 | 28.6±5.3 | 28.7±7.1 | 0.275 |
| Family history of coronary artery disease | 7395 (30.7) | 687 (29.8) | 0.350 |
| Hypertension | 18 350 (76.2) | 1848 (80.1) | <0.001 |
| Dyslipidemia | 17 550 (72.9) | 1704 (73.8) | 0.362 |
| Diabetes | 7456 (38.2) | 750 (39.6) | 0.244 |
| Never smokers | 7883 (36.8) | 811 (39.9) | 0.005 |
| Ex‐smokers | 7528 (35.2) | 713 (35.1) | 0.005 |
| Current smokers | 5999 (28.0) | 509 (25.0) | 0.005 |
| Peripheral artery disease | 2736 (11.4) | 367 (15.9) | <0.001 |
| Chronic obstructive pulmonary disease | 1464 (6.1) | 156 (6.8) | 0.213 |
| Dialysis‐dependent renal disease | 353 (1.5) | 49 (2.1) | 0.018 |
| Prior stroke | 832 (3.5) | 90 (3.9) | 0.296 |
| Atrial fibrillation | 708 (6.0) | 75 (6.7) | 0.417 |
| Estimated glomerular filtration rate, mL/min per 1.73 m2 | 71.2±26.1 | 70.1±26.1 | 0.075 |
| Prior myocardial infarction | 8100 (39.1) | 760 (38.2) | 0.442 |
| Prior coronary artery bypass grafting | 2957 (12.3) | 345 (14.9) | <0.001 |
| Prior PCI | 12 266 (51.0) | 1266 (54.9) | <0.001 |
| LVEF ≥50% | 17 371 (72.7) | 1674 (73.1) | 0.595 |
| LVEF 35–50% | 4973 (20.8) | 477 (20.8) | 0.595 |
| LVEF <35% | 1547 (6.5) | 140 (6.1) | 0.595 |
Values are mean±SD or n (%). P values compare non–aorto‐ostial vs aorto‐ostial RCA CTO lesions. Percentages are based on available data; denominators vary with missing values. CTO indicates chronic total occlusion; LVEF, left ventricular ejection fraction; PCI, percutaneous coronary intervention; and RCA, right coronary artery.
Lesion and angiographic characteristics are summarized in Table 2. Three‐vessel coronary artery disease was more frequent in aorto‐ostial lesions (35.6% versus 32.5%; P=0.001). Mean J‐CTO score was significantly higher in the aorto‐ostial group (3.0±1.1 versus 2.4±1.2; P<0.001). Aorto‐ostial CTOs exhibited a substantially higher prevalence of stumpless proximal caps (34.9% versus 13.8%; P<0.001) and severe calcification (36.7% versus 20.1%; P<0.001). Furthermore, the aorto‐ostial group showed a higher proportion of collateral circulation grade 2 or 3 compared with the non–aorto‐ostial group (31.5% versus 34.9% and 2.4% versus 2.2%, respectively; P=0.001). In‐stent CTOs (17.1% versus 8.7%, P<0.001) and involvement of more than one coronary segment (45.5% versus 32.0%, P<0.001) were more common in aorto‐ostial compared with non–aorto‐ostial group. Conversely, bifurcation involvement was less prevalent in aorto‐ostial CTOs (13.0% versus 23.2%; P<0.001).
Table 2.
Angiographic and Lesion Characteristics of RCA CTO According to Aorto‐Ostial Versus Non–Aorto‐Ostial Lesion Location
| Variable | Non–aorto‐ostial RCA CTO (n=23 524) | Aorto‐ostial RCA CTO (n=2850) | P value |
|---|---|---|---|
| Japanese ‐CTO score | 2.4±1.2 | 3.0±1.1 | <0.001 |
| European CTO score | 2.2±1.2 | 2.8±1.1 | <0.001 |
| Prospective Global Registry for the Study of Chronic Total Occlusion Intervention‐CTO score | 1.8±1.0 | 2.0±1.0 | <0.001 |
| In‐stent CTO | 2101 (8.7) | 394 (17.1) | <0.001 |
| >1 segment involved | 7700 (32.0) | 1051 (45.5) | <0.001 |
| Bifurcation involvement | 5591 (23.2) | 301 (13.0) | <0.001 |
| Occlusion length >20 mm | 11 778 (54.6) | 1173 (56.3) | 0.132 |
| In‐CTO bend >45° | 8411 (47.2) | 1024 (57.9) | <0.001 |
| Side branch ≤3 mm proximal | 5523 (23.0) | 285 (12.3) | <0.001 |
| Multivessel coronary artery disease | |||
| 1‐vessel disease | 8867 (37.7) | 859 (37.9) | <0.001 |
| 2‐vessel disease | 7008 (29.8) | 602 (26.6) | |
| 3‐vessel disease | 7652 (32.5) | 806 (35.6) | |
| Bifurcation location | |||
| Within the CTO body | 363 (13.8) | 15 (9.9) | <0.001 |
| Proximal to CTO | 591 (22.5) | 8 (5.3) | |
| Distal to CTO | 1672 (63.7) | 128 (84.8) | |
| Collateral filling pattern | |||
| Ipsilateral | 6584 (29.4) | 285 (13.5) | <0.001 |
| Contralateral | 15 599 (69.7) | 1809 (85.9) | |
| Bridging | 187 (0.8) | 11 (0.5) | |
| Collateral circulation grade | |||
| CC0 | 1434 (7.3) | 105 (5.4) | <0.001 |
| CC1 | 11 524 (58.8) | 1118 (57.5) | |
| CC2 | 6182 (31.5) | 678 (34.9) | |
| CC3 | 463 (2.4) | 43 (2.2) | |
| Tortuosity | |||
| Straight | 10 661 (49.7) | 1044 (60.1) | <0.001 |
| Slight | 7023 (32.8) | 417 (24.0) | |
| Moderate | 2990 (13.9) | 200 (11.5) | |
| Severe | 770 (3.6) | 75 (4.3) | |
| Calcification severity | |||
| None | 4231 (18.4) | 277 (12.5) | <0.001 |
| Mild | 7386 (32.2) | 499 (22.4) | |
| Moderate | 6743 (29.4) | 632 (28.4) | |
| Severe | 4608 (20.1) | 815 (36.7) | |
| Proximal cap morphology | |||
| No stump | 3203 (13.8) | 784 (34.9) | <0.001 |
| Blunt stump | 9715 (41.9) | 1046 (46.6) | |
| Tapered stump | 10 294 (44.3) | 414 (18.4) | |
| Distal opacification | |||
| Not visible | 1540 (7.4) | 209 (10.2) | <0.001 |
| Faint | 9828 (47.1) | 874 (42.8) | |
| Good | 9519 (45.6) | 961 (47.0) | |
| Distal vessel disease | |||
| Minimal | 11 286 (56.5) | 1041 (53.2) | 0.016 |
| Severe and vessel diameter ≥2 mm | 6998 (35.0) | 730 (37.3) | |
| Severe and vessel diameter <2 mm | 1701 (8.5) | 187 (9.6) | |
Values are n (%). P values compare non–aorto‐ostial vs aorto‐ostial RCA CTO lesions. Percentages are based on available data; denominators vary with missing values. Proximal tortuosity was categorized as straight (<70° single bend), slight (>70° single bend), moderate (2 bends >70° or 1 bend >90°), or severe (2 bends >90° or 1 bend >120°). Collateral circulation was graded as CC0 (no connection), CC1 (thread‐like connection), CC2 (small side‐branch–like connection), or CC3 (large collateral channel). CC indicates collateral circulation; CTO, chronic total occlusion; and RCA, right coronary artery.
Procedural characteristics are reported in Table 3. Antegrade wire escalation was used in 34.1% of aorto‐ostial group compared with 61.7% of non–aorto‐ostial (P<0.001), whereas retrograde approach was more frequently used in the aorto‐ostial group, including retrograde dissection and reentry (25.2% versus 17.3%; P<0.001) and retrograde wire escalation (27.0% versus 9.1%; P<0.001).
Table 3.
Procedural Characteristics, Technical Outcomes, and Final Crossing Strategy According to Lesion Location
| Variable | Non–aorto‐ostial RCA CTO (n=23 524) | Aorto‐ostial RCA CTO (n=2850) | P value |
|---|---|---|---|
| Retrograde collateral pathway | |||
| Epicardial | 1385 (18.7) | 237 (18.4) | 0.559 |
| Septal | 5796 (78.2) | 1019 (79.0) | |
| Graft | 235 (3.2) | 34 (2.6) | |
| Collateral reverse bend >90° | 810 (7.5) | 138 (13.4) | <0.001 |
| Use of dedicated devices | |||
| Intravascular lithotripsy | 159 (1.5) | 38 (3.7) | <0.001 |
| Rotational atherectomy | 810 (3.4) | 104 (4.5) | 0.005 |
| Stingray | 517 (2.1) | 31 (1.3) | 0.012 |
| Intravascular ultrasound | 4015 (16.7) | 470 (20.4) | <0.001 |
| Impenetrable proximal cap | 437 (4.1) | 95 (9.2) | <0.001 |
| Anchoring balloon | 2623 (10.9) | 181 (7.8) | <0.001 |
| Externalization | 4579 (19.0) | 818 (35.4) | <0.001 |
| Snaring | 348 (1.4) | 299 (13.0) | <0.001 |
| Tip‐in | 774 (4.6) | 101 (6.3) | 0.003 |
| Drug‐eluting balloon use | 1717 (7.2) | 172 (7.5) | 0.683 |
| Procedural time, min | 106.9±65.0 | 129.1±57.7 | <0.001 |
| Fluoroscopy time, min | 44.1±35.4 | 56.5±29.9 | <0.001 |
| Contrast volume, ml | 237.4±130.9 | 254.6±125.9 | <0.001 |
| Air Kerma, mGy | 2175.5±2940.9 | 2566.9±3546.8 | <0.001 |
| Final crossing strategy | |||
| AW without retrograde contribution | 14 412 (61.6%) | 760 (34.1%) | <0.001 |
| AW with retrograde contribution | 1378 (5.9%) | 195 (8.7%) | |
| ADR without retrograde contribution | 4075 (17.4%) | 561 (25.2%) | |
| ADR with retrograde contribution | 2133 (9.1%) | 603 (27.0%) | |
| Retrograde dissection and reentry | 823 (3.5%) | 57 (2.6%) | |
| Retrograde wiring escalation | 579 (2.5%) | 54 (2.4%) | |
Values are n (%). P values compare non–aorto‐ostial vs aorto‐ostial RCA CTO lesions. Percentages are based on available data; denominators vary with missing values. ADR indicates antegrade dissection and re‐entry; and AW, antegrade wiring.
Advanced calcific plaque modification devices were more often used in the aorto‐ostial group (intravascular lithotripsy: 3.7% versus 1.5%; P<0.001; rotational atherectomy: 4.5% versus 3.4%; P=0.005). Similarly, intravascular ultrasound use was higher in aorto‐ostial cases (20.4% versus 16.7%; P<0.001).
Aorto‐ostial RCA CTO PCI showed higher procedural time (129.1±57.7 versus 106.9±65.0 minutes; P<0.001), higher fluoroscopy time (56.5±29.9 versus 44.1±35.5 minutes; P<0.001), higher contrast load (254.6±125.9 versus 237.6±131.4 mL; P<0.001), and a higher radiation exposure (air kerma 2566.9±3546.8 versus 2184.8±3078.8 mGy; P<0.001).
Primary Outcome
Technical success was achieved in 23 436 of 26 374 procedures (88.8%). Success rates were significantly lower in aorto‐ostial compared with non–aorto‐ostial RCA CTOs (79.6% versus 89.7%; P<0.001) (Figure 2). Within a multivariable model applied to the overall cohort, aorto‐ostial location was independently associated with technical failure (adjusted odds ratio [OR], 1.85 [95% CI 1.59–2.17]; P<0.001), after adjustment for clinical and angiographic characteristics (Figure S1).
Figure 2. Technical success in aorto‐ostial versus non–aorto‐ostial RCA CTO PCI.
Technical success rates were significantly lower in aorto‐ostial lesions compared with non–aorto‐ostial lesions (89.7% vs 79.6%; P < 0.001). Bars represent the proportion of procedures achieving technical success. CTO indicates chronic total occlusion; PCI, percutaneous coronary intervention; and RCA, right coronary artery.
Within the prespecified multivariable model restricted to aorto‐ostial RCA CTOs (Figure 3), stumpless proximal cap morphology (adjusted OR, 2.44 [95% CI, 1.83–3.26; P<0.001), moderate‐to‐severe tortuosity (adjusted OR, 2.13 [95% CI, 1.48–3.06]]; P<0.001), and moderate‐to‐severe calcification (adjusted OR, 1.92 [95% CI, 1.37–2.69]; P<0.001) were independently associated with technical failure. Among clinical characteristics, peripheral artery disease emerged as an independent associate of failure (adjusted OR, 1.57 [95% CI, 1.11–2.22]; P=0.011), whereas prior coronary artery bypass grafting showed only a borderline, nonsignificant association (adjusted OR, 1.42 [95% CI, 0.99–2.03]; P=0.057).
Figure 3. Predictors of technical failure in aorto‐ostial RCA CTO PCI: multivariable logistic regression model.
CABG indicates coronary artery bypass grafting; CTO, chronic total occlusion; MI, myocardial infarction; OR, odds ratio; PCI, percutaneous coronary intervention; and RCA, right coronary artery.
Secondary Outcome
In‐hospital clinical outcomes were available for 25 199 patients, corresponding to 2230 aorto‐ostial and 22 969 non–aorto‐ostial RCA CTO procedures. The overall incidence of MACCE was numerically higher in aorto‐ostial versus non–aorto‐ostial lesions (2.3% versus 1.8%; P=0.076; Table 4, Figure 1), although this difference did not reach statistical significance. Mortality rates were similar between the groups (0.5% versus 0.4%; P=0.426), as was the incidence of myocardial infarction (1.0% versus 0.7%; P=0.121). Stroke was rare, occurring in 0% of aorto‐ostial cases and 0.1% of non–aorto‐ostial cases (P=0.227). Rates of urgent revascularization (0.5% versus 0.4%; P=0.653) and the need for urgent pericardiocentesis (0.7% versus 0.5%; P=0.228) did not differ significantly between the groups.
Table 4.
Incidence of In‐Hospital MACCE in Patients With Non–Aorto‐Ostial Versus Aorto‐Ostial RCA CTO PCI
| Outcome | Non–aorto‐ostial RCA CTO (n=22 969) | Aorto‐ostial RCA CTO (n=2230) | P value |
|---|---|---|---|
| MACCE | 418 (1.8) | 53 (2.3) | 0.076 |
| Death | 92 (0.4) | 12 (0.5) | 0.426 |
| Myocardial infarction | 155 (0.7) | 22 (1.0) | 0.121 |
| Stroke | 25 (0.1) | 0 (0.0) | 0.227 |
| Urgent Pericardiocentesis | 115 (0.5) | 16 (0.7) | 0.228 |
| Urgent revascularization | 94 (0.4) | 11 (0.5) | 0.653 |
| PCI | 64 (0.3) | 8 (0.4) | 0.639 |
| Coronary artery bypass grafting | 30 (0.1) | 3 (0.1) | 1.000 |
Values are n (%). P values compare non–aorto‐ostial vs aorto‐ostial RCA CTO lesions. Outcomes were assessed in procedures with available in‐hospital follow‐up. CTO indicates chronic total occlusion; MACCE, Major adverse cardiac and cerebrovascular events PCI, percutaneous coronary intervention; and RCA, right coronary artery.
Other procedural complications were also comparable (Table 5). Major vascular complications occurred in 0.7% of the aorto‐ostial group versus 0.6% in the non–aorto‐ostial group (P=0.904). The incidence of contrast‐associated acute kidney injury (1.0% versus 1.0%; P=1.000) and hemoglobin reduction >3 g/dL (0.2% versus 0.2%; P=1.000) was identical between groups. Finally, prolonged hospital stay (>3 days) occurred in 0.4% of aorto‐ostial procedures compared with 0.2% of non–aorto‐ostial procedures (P=0.334).
Table 5.
Procedural and In‐Hospital Safety Outcomes
| Outcome | Non–aorto‐ostial RCA CTO (n=22 969) | Aorto‐ostial RCA CTO (n=2230) | P value |
|---|---|---|---|
| Major vascular complications | 144 (0.6) | 15 (0.7) | 0.904 |
| Contrast‐associated acute kidney injury | 228 (1.0) | 22 (1.0) | 1.000 |
| Hemoglobin reduction >3 g/dL | 46 (0.2) | 5 (0.2) | 1.000 |
| Prolonged hospital stay >3 d | 65 (0.2) | 9 (0.4) | 0.334 |
| Minor coronary perforation | 263 (2.5) | 33 (3.3) | 0.115 |
| Coronary perforation requiring treatment | 200 (1.9) | 26 (2.6) | 0.119 |
Values are n (%). P values compare non–aorto‐ostial vs aorto‐ostial RCA CTO lesions. Outcomes were assessed in procedures with available in‐hospital follow‐up. CTO indicates chronic total occlusion; and RCA, right coronary artery.
DISCUSSION
The present analysis provides a comprehensive, contemporary evaluation of aorto‐ostial RCA CTOs within a large, multicenter European registry (Figure 4). The main findings of the present analysis can be summarized as follows. First, aorto‐ostial RCA CTOs accounted for 10.8% of all RCA CTOs in the ERCTO registry, underscoring their nonnegligible prevalence in contemporary practice. Second, aorto‐ostial lesions were characterized by markedly greater anatomical complexity, reflected by higher J‐CTO and European Chronic Total Occlusion Score scores, a higher prevalence of stumpless proximal caps, and more severe calcification and tortuosity. Third, despite more frequent use of advanced techniques—including retrograde approaches, advanced calcium modification devices, and intravascular imaging—technical success remained significantly lower in aorto‐ostial compared with non–aorto‐ostial RCA CTOs, and procedures were associated with longer duration, higher radiation exposure, and greater contrast use. Fourth, multivariable analysis demonstrated that technical failure in aorto‐ostial RCA CTOs was driven predominantly by lesion‐specific anatomical factors—stumpless proximal cap morphology, severe calcification, and moderate‐to‐severe tortuosity—as well as by peripheral artery disease as the only independent clinical predictor. Finally, although overall in‐hospital adverse event rates were low, aorto‐ostial RCA CTO PCI was not associated with a statistically significant excess of in‐hospital MACCE compared with non–aorto‐ostial RCA CTOs.
Figure 4. Aorto‐ostial right coronary artery chronic total occlusion percutaneous coronary intervention: insights from the ERCTO Registry.
A, Study population derived from the ERCTO registry, including 26 374 patients undergoing RCA CTO PCI, of whom 2850 (10.8%) had aorto‐ostial RCA CTO and 23 524 (89.2%) had non–aorto‐ostial RCA CTO. B, Technical success rates according to lesion location, demonstrating significantly lower technical success in aorto‐ostial vs non–aorto‐ostial RCA CTO PCI (79.6% vs 89.7%; P<0.001). C, In‐hospital MACCE and individual components, showing low event rates and no statistically significant differences between aorto‐ostial and non–aorto‐ostial RCA CTO PCI. D, Key anatomical predictors of technical failure in aorto‐ostial RCA CTO PCI, including stumpless proximal cap morphology, moderate–severe calcification, and moderate‐to‐severe tortuosity. CTO indicates chronic total occlusion; ERCTO, European Registry of Chronic Total Occlusion; MACCE, major adverse cardiovascular and cerebrovascular events; PCI, percutaneous coronary intervention; and RCA, right coronary artery.
This large multicenter registry analysis confirms that aorto‐ostial RCA CTOs constitute a distinct and particularly complex lesion subset, with significantly lower technical compared with non–aorto‐ostial RCA CTOs. These findings underscore the unique anatomical and procedural challenges of aorto‐ostial CTOs and provide the most comprehensive assessment to date of this high‐risk lesion subset.
Aorto‐ostial occlusions accounted for about 1 in 10 RCA CTOs in our series, which is higher than previously reported in a prior study focusing on aorto‐ostial CTOs. 9 This discrepancy may be partly explained by differences in study populations: while our investigation was restricted to RCA CTOs, the previous study also included aorto‐ostial left main CTOs, which are considerably less common. Their inclusion likely diluted the overall prevalence, thus accounting for the observed epidemiological differences.
Patients with aorto‐ostial RCA CTOs exhibited a higher overall disease burden, including higher rates of prior coronary revascularization and peripheral artery disease, consistent with more diffuse and aggressive atherosclerosis. From an anatomical standpoint, aorto‐ostial lesions displayed multiple hostile features (higher J‐CTO scores, frequent stumpless proximal caps, and more severe calcification and tortuosity) findings that align with previous reports identifying ostial location as a marker of increased CTO complexity. 8 , 9 , 15 , 16
The high adoption of retrograde strategies highlights the technical challenge, often requiring a septal crossing, externalization, or snaring strategies in a higher proportion than typically reported in contemporary CTO PCI series. 2
These anatomical challenges translated into distinct procedural characteristics. Aorto‐ostial RCA CTOs were approached more frequently with retrograde strategies, including externalization and snaring techniques, reflecting the limited feasibility of straightforward antegrade wire escalation in the absence of a clearly defined proximal cap. 2 Similarly, the more frequent use of advanced calcium modification devices and intravascular ultrasound highlights the need for aggressive lesion preparation and optimization in this setting. These observations are consistent with prior ERCTO analyses demonstrating that the need for calcium modification identifies a particularly complex CTO phenotype that nevertheless can be treated safely in experienced centers. 7 Despite the more frequent adoption of advanced techniques, together with longer procedural time and higher radiation exposure, technical success rates remained significantly lower in aorto‐ostial compared with non–aorto‐ostial CTOs.
From a practical standpoint, guide catheter selection and coaxial engagement are particularly critical in aorto‐ostial CTOs: the absence of a defined proximal stump limits coaxial alignment, and aggressive catheter manipulation carries a risk of iatrogenic dissection. The use of Amplatz Left or specifically shaped catheters with side holes, guide catheter extensions, and anchoring techniques may help overcome these challenges. When antegrade wire escalation is not feasible, early consideration of retrograde approaches is warranted, as reflected by the high proportion of retrograde strategies, externalization, and snaring observed in our cohort.
Despite lower success rates, the overall technical success of 79.6% in this anatomically complex group compares favorably with prior smaller studies and it reflects the feasibility of these challenging cases in experienced centers. 8 , 17 Moreover, although procedures were longer and more resource‐intensive, aorto‐ostial RCA CTO PCI was not associated with a statistically significant increase in in‐hospital MACCE, providing reassurance regarding procedural safety in appropriately selected. Notably, predictors of technical failure in aorto‐ostial RCA CTOs were driven predominantly by lesion‐specific anatomical factors. Stumpless proximal cap morphology was independently associated with failure, reflecting the difficulty of establishing guide catheter stability and achieving initial wire entry when the occlusion is flush with the aortic wall. Moderate‐to‐severe tortuosity and calcification, which represent well‐established markers of CTO complexity, 10 remained robust independent associates of failure in this anatomical context. Among clinical variables, peripheral artery disease was the only independent associate of failure, likely serving as a surrogate for diffuse systemic atherosclerosis and adverse vascular biology rather than lesion‐specific technical constraints.
Collectively, these data reinforce that aorto‐ostial RCA CTOs remain among the most technically demanding scenarios in contemporary CTO PCI. They highlight the importance of careful patient selection, referral to experienced centers, and the routine use of advanced techniques and imaging in this setting. Future studies should aim to validate dedicated risk models incorporating aorto‐ostial–specific anatomical features and to assess whether long‐term clinical outcomes differ from those observed after non–aorto‐ostial CTO PCI.
LIMITATIONS
This study has several limitations. First, it is a retrospective analysis of a multicenter registry, and residual confounding and selection bias cannot be excluded. Second, procedural strategies and device use were left to the operators' discretion and may have varied across centers and over time, potentially influencing outcomes. Third, although the ERCTO Registry captures core data, some baseline variables had missingness, which we addressed using multiple imputation; nevertheless, residual bias cannot be excluded. Fourth, only in‐hospital outcomes were systematically collected; therefore, longer‐term follow‐up regarding restenosis, reocclusion, or clinical benefit is unavailable. Fifth, as all participating operators were highly experienced CTO operators at high‐volume centers, the generalizability of these findings to lower‐volume settings may be limited. Sixth, the registry does not fully capture the sequence of wiring techniques or the intraprocedural decision‐making, which may have further influenced technical success or failure. Moreover, selection bias may disproportionately affect the aorto‐ostial subgroup, as operators may have been less likely to attempt PCI in cases with particularly hostile anatomy (such as the absence of both an antegrade target and viable retrograde options) potentially leading to an underestimation of the true difficulty associated with this lesion subset. Finally, although intravascular ultrasound guidance was used more frequently in aorto‐ostial lesions, its overall penetration remained modest, likely reflecting heterogeneity in institutional practices, reimbursement frameworks, thus limiting the ability to assess the true impact of intravascular imaging on outcomes in this specific anatomical setting.
CONCLUSIONS
Aorto‐ostial RCA CTOs constitute a frequent and anatomically complex subset of CTO interventions and are associated with significantly lower technical success compared with non–aorto‐ostial RCA CTOs, despite greater use of advanced procedural strategies. Technical failure was primarily associated with lesion‐specific anatomical features, particularly stumpless proximal cap morphology, severe calcification, and moderate‐to‐severe tortuosity, with peripheral artery disease as the only clinical variable independently associated with failure. These findings underscore the need for dedicated technical approaches and refined risk stratification tools tailored to the unique challenges of aorto‐ostial CTOs.
Sources of Funding
This research received no external funding.
Disclosures
Dr Ioannis Skalidis is supported by grant from the Gottfried and Julia Bangerter‐Rhyner Foundation and from the Professor Dr Max Cloëtta Foundation. Dr Luca Esposito received a research grant by the CardioPath PhD program from the Federico II University of Naples, Italy. Dr Werner has received speaking honoraria from Abbott Laboratories, Asahi Intecc, OrbusNeich, Philips, Siemens Healthineers, and Terumo. Dr Diletti has received consulting and proctoring honoraria from Asahi Intecc, Terumo, IMDS, Boston Scientific, Teleflex, and Philips. Dr Goktekin has received consulting, speaking, and proctoring honoraria from Boston Scientific, Medtronic, MicroPort, and Asahi Intecc. Dr Boudou is a proctor and consultant for Asahi Intecc, Terumo, and Boston Scientific. Dr Agostoni has received consulting honoraria from Abbott Laboratories, Boston Scientific, Shockwave Medical, Teleflex, and Terumo. Dr Mashayekhi has received consulting, speaking, and proctoring honoraria from Abbott, Abiomed, Asahi Intecc, AstraZeneca, Biotronik, Boston Scientific, Cardinal Health, Daiichi‐Sankyo, Medtronic, OrbusNeich, Shockwave Medical, Teleflex, and Terumo. Dr Di Mario has received research or educational grants from Abbott Laboratories, Amgen, Asahi Intecc, AstraZeneca, Boston Scientific, Cardinal Health, Behring, Chiesi, Daiichi‐Sankyo, Edwards Lifesciences, Medtronic, Menarini, Pfizer, Sanofi, Shockwave Medical, Teleflex, and Volcano‐Philips. Dr Avran has received consulting, speaking, and proctoring honoraria from Asahi Intecc, Biotronik, Boston Scientific, Terumo, Alvimedica, and OrbusNeich. The Euro CTO Club receives annual grants to support its congress and other activities from Abbott Laboratories, Asahi Intecc, Biotronik, Boston Scientific, Braun, IMDS, OrbusNeich, Philips Volcano, Shockwave Medical, SIS Medical, Teleflex, and Terumo. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Supporting information
Figure S1
Data S1: STROBE Checklist
This article was sent to Saket Girotra, MD, SM, Associate Editor, for review by expert referees, editorial decision, and final disposition.
Supplemental Material is available at https://www.ahajournals.org/doi/suppl/10.1161/JAHA.126.051613
For Sources of Funding and Disclosures, see page 11.
REFERENCES
- 1. Suzuki Y, Tsuchikane E, Katoh O, Muramatsu T, Muto M, Kishi K, Hamazaki Y, Oikawa Y, Kawasaki T, Okamura A. Outcomes of percutaneous coronary interventions for chronic total occlusion performed by highly experienced Japanese specialists: the first report from the Japanese CTO‐PCI Expert Registry. JACC Cardiovasc Interv. 2017;10:2144–2154. doi: 10.1016/j.jcin.2017.06.024 [DOI] [PubMed] [Google Scholar]
- 2. Vadalà G, Galassi AR, Werner GS, Sianos G, Boudou N, Garbo R, Maniscalco L, Bufe A, Avran A, Gasparini GL, et al. Contemporary outcomes of chronic total occlusion percutaneous coronary intervention in Europe: the ERCTO registry. EuroIntervention. 2024;20:e185–e197. doi: 10.4244/EIJ-D-23-00490 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Tajti P, Karmpaliotis D, Alaswad K, Jaffer FA, Yeh RW, Patel M, Mahmud E, Choi JW, Burke MN, Doing AH, et al. The hybrid approach to chronic Total occlusion percutaneous coronary intervention: update from the PROGRESS CTO registry. JACC Cardiovasc Interv. 2018;11:1325–1335. doi: 10.1016/j.jcin.2018.02.036 [DOI] [PubMed] [Google Scholar]
- 4. Rempakos A, Simsek B, Kostantinis S, Karacsonyi J, Choi JW, Poommipanit P, Khatri JJ, Jaber W, Rinfret S, Nicholson W, et al. Impact of lesion length on the outcomes of chronic total occlusion percutaneous coronary intervention: insights from the PROGRESS‐CTO registry. Catheter Cardiovasc Interv. 2023;101:747–755. doi: 10.1002/ccd.30581 [DOI] [PubMed] [Google Scholar]
- 5. Myat A, Galassi AR, Werner GS, Mashayekhi K, Avran A, Boudou N, Meyer‐Gessner M, Reifart N, Lesiak M, Garbo R, et al. Retrograde chronic total occlusion percutaneous coronary interventions: predictors of procedural success from the ERCTO registry. JACC Cardiovasc Interv. 2022;15:834–842. doi: 10.1016/j.jcin.2022.02.013 [DOI] [PubMed] [Google Scholar]
- 6. Rempakos A, Alexandrou M, Mutlu D, Kalyanasundaram A, Ybarra LF, Bagur R, Choi JW, Poommipanit P, Khatri JJ, Young L, et al. Predicting successful chronic total occlusion crossing with primary antegrade wiring using machine learning. JACC Cardiovasc Interv. 2024;17:1707–1716. doi: 10.1016/j.jcin.2024.04.043 [DOI] [PubMed] [Google Scholar]
- 7. Vadalà G, Mashayekhi K, Behnes M, Ayoub M, Gorgulu S, Werner GS, Kalay N, Avran A, Goktekin O, Garbo R, et al. Procedural impact of advanced calcific plaque modification devices within percutaneous revascularization of chronic total occlusions. JACC Cardiovasc Interv. 2025;18:1376–1390. doi: 10.1016/j.jcin.2025.04.035 [DOI] [PubMed] [Google Scholar]
- 8. Ojeda S, Luque A, Pan M, Bellini B, Xenogiannis I, Lostalo A, Montorfano M, Hidalgo F, Venuti G, la Manna A, et al. Percutaneous coronary intervention in aorto‐ostial coronary chronic total occlusion: outcomes and technical considerations in a multicenter registry. Rev Esp Cardiol (Engl Ed). 2020;73:1011–1017. doi: 10.1016/j.recesp.2020.01.018 [DOI] [PubMed] [Google Scholar]
- 9. Niizeki T, Tsuchikane E, Konta T, Kishi K, Okada H, Ito Y, Oikawa Y, Yoshikawa R, Tanaka H. Percutaneous coronary intervention for aorto‐ostial chronic total occlusion: evaluating lesion complexity and procedural outcomes. JACC Cardiovasc Interv. 2024;17:2243–2255. doi: 10.1016/j.jcin.2024.08.028 [DOI] [PubMed] [Google Scholar]
- 10. Morino Y, Abe M, Morimoto T, Kimura T, Hayashi Y, Muramatsu T, Ochiai M, Noguchi Y, Kato K, Shibata Y, et al. Predicting successful guidewire crossing through chronic total occlusion of native coronary lesions within 30 minutes: the J‐CTO (multicenter CTO registry in Japan) score as a difficulty grading and time assessment tool. JACC Cardiovasc Interv. 2011;4:213–221. doi: 10.1016/j.jcin.2010.09.024 [DOI] [PubMed] [Google Scholar]
- 11. Christopoulos G, Kandzari DE, Yeh RW, Jaffer FA, Karmpaliotis D, Wyman MR, Alaswad K, Lombardi W, Grantham JA, Moses J, et al. Development and validation of a novel scoring system for predicting technical success of chronic total occlusion percutaneous coronary interventions: the PROGRESS CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) score. JACC Cardiovasc Interv. 2016;9:1–9. doi: 10.1016/j.jcin.2015.09.022 [DOI] [PubMed] [Google Scholar]
- 12. Lefèvre T, Pan M, Stankovic G, Ojeda S, Boudou N, Brilakis ES, Sianos G, Vadalà G, Galassi AR, Garbo R, et al. CTO and bifurcation lesions: an expert consensus from the European Bifurcation Club and EuroCTO Club. JACC Cardiovasc Interv. 2023;16:2065–2082. doi: 10.1016/j.jcin.2023.06.042 [DOI] [PubMed] [Google Scholar]
- 13. Ybarra LF, Rinfret S, Brilakis ES, Karmpaliotis D, Azzalini L, Grantham JA, Kandzari DE, Mashayekhi K, Spratt JC, Wijeysundera HC, et al. Definitions and clinical trial design principles for coronary artery chronic total occlusion therapies: CTO‐ARC consensus recommendations. Circulation. 2021;143:479–500. doi: 10.1161/CIRCULATIONAHA.120.046754 [DOI] [PubMed] [Google Scholar]
- 14. Vadalà G, Mashayekhi K, Boukhris M, Behnes M, Pyxaras S, Christiansen EH, Gutiérrez‐Chico JL, Maniscalco L, Stojkovic S, Bozinovic NZ, et al. Reclassification of CTO crossing strategies in the ERCTO registry according to the CTO‐ARC consensus recommendations. JACC Cardiovasc Interv. 2024;17:2425–2437. doi: 10.1016/j.jcin.2024.09.002 [DOI] [PubMed] [Google Scholar]
- 15. Alexandrou M, Kostantinis S, Rempakos A, Simsek B, Karacsonyi J, Choi JW, Poommipanit P, Alaswad K, Basir MB, Megaly M, et al. Outcomes of chronic total occlusion percutaneous coronary interventions in patients with previous coronary artery bypass graft surgery. Am J Cardiol. 2023;205:40–49. doi: 10.1016/j.amjcard.2023.07.112 [DOI] [PubMed] [Google Scholar]
- 16. Tajti P, Karmpaliotis D, Alaswad K, Jaffer FA, Yeh RW, Patel M, Mahmud E, Choi JW, Burke MN, Doing AH, et al. In‐hospital outcomes of chronic total occlusion percutaneous coronary interventions in patients with prior coronary artery bypass graft surgery. Circ Cardiovasc Interv. 2019;12:e007338. doi: 10.1161/CIRCINTERVENTIONS.118.007338 [DOI] [PubMed] [Google Scholar]
- 17. Allana SS, Kostantinis S, Simsek B, Karacsonyi J, Rempakos A, Alaswad K, Krestyaninov O, Khelimskii D, Karmpaliotis D, Jaffer F, et al. Lesion complexity and procedural outcomes associated with ostial chronic total occlusions: insights from the PROGRESS‐CTO registry. J Invasive Cardiol. 2023;35. doi: 10.25270/jic/23.00034 [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Figure S1
Data S1: STROBE Checklist