Chronic total occlusion (CTO) percutaneous coronary intervention is a complex procedure and is associated with considerable risk of complications. Several success and complication scores have been developed; however, data regarding their external validation in other populations such as Latin America are scarce. This study aimed to evaluate the accuracy of the main predictors of success and complications in a broad cohort of procedures in the Latin American (LATAM) CTO registry. From April 2008 to December 2023, 3,706 consecutive procedures listed in the LATAM CTO registry were screened. Of these, 2,835 procedures had sufficient information to analyze the Multicenter CTO Registry in Japan (J-CTO); Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS); Ostial location, Rentrop grade, and Age (ORA); Clinical and Lesion-related Score (CL-score); and EuroCTO Score (CASTLE) success scores. The complication scores were PROGRESS (MACE, mortality, and pericardiocentesis) and Outcomes, Patient health status, and Efficiency iN Chronic Total Occlusion hybrid procedures (OPEN-CTO),OPEN-CLEAN. The J-CTO and CASTLE scores demonstrated the highest areas under the curve (AUC) of 0.718 and 0.703, respectively. The AUC value for the CL-score was 0.685, whereas the PROGRESS score had an AUC of 0.598 and the ORA AUC was 0.545. The level of agreement between scores was low; only 4% of the procedures were classified as difficult or very difficult by all scores and <1% were classified as easy by all 5 scores. Of the complication scores, PROGRESS mortality (AUC 0.651) and PROGRESS MACE (AUC 0.588) showed the best performance, identifying groups with >10% event rate. These results may improve the selection of revascularization techniques, especially for patient demographics that are historically underrepresented in CTO research.
Over the past decade, considerable progress has been made in the field of chronic total occlusion (CTO) revascularization. The development and validation of risk scores to predict success and complication rates was an important step forward to adequately apply these procedures in daily practice. Because the primary indication for CTO revascularization is symptom control, a comprehensive preprocedural evaluation is crucial to carefully determine the balance between risks and benefits. However, there is a lack of data regarding the accuracy of these scores in the context of middle and low-income countries, which may present significantly different realities than in cohorts where the scores were validated. This study aimed to evaluate the accuracy of the main predictors of success and complications in a cohort of patients treated by CTO percutaneous coronary intervention (PCI) in Latin America (LATAM) to provide insights for clinical practice in this and other regions with similar socioeconomic and cultural characteristics.
Methods
The present work assessed data from the LATAM CTO registry, which has been described elsewhere. The LATAM CTO registry is an ongoing international observational study from more than 70 centers in Latin America (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, Mexico, and Puerto Rico). There is no specific requirement regarding CTO PCI volume and operator’s experience for entering data into the registry.
CTO PCI data were included in an online platform coordinated by the group of investigators, in partnership with the Brazilian Society of Interventional Cardiology, and managed by the Instituto de Cardiologia do Rio Grande do Sul, Brazil. Access to the database was available by way of research electronic data capture (REDCap), a secure and free-access web application developed by Vanderbilt University that meets international standards and requirements from the National Agency for Sanitary Surveillance in our country. All investigators received standardized instructions for data entry in REDCap and clinical, procedural, angiographic information, and postprocedural clinical outcomes were collected on the same platform. The centers received online support for questions regarding inclusion or completion of cases and monthly feedback for missing data and discrepant values. All the variables required for the scores calculations were independently collected in the database. The scores results were generated automatically without manual interference during the filling process.
Moderate/severe calcification was defined as a >50% involvement of the vessel by angiography, and moderate/severe tortuosity was the presence of at least 2 bends >70° or 1 bend >90° in the proximal vessel. Bending was defined as at least 1 bend of 45° assessed by angiography throughout the occluded segment divided into either CTO entry or CTO body. The proximal cap was defined as tapered if the occluded segment ended in a funnel-shaped form. Interventional collateral vessels were side branches considered amenable to crossing by a guidewire and a microcatheter by the operator. The following strategies were generally considered for CTO PCI. Anterograde wire escalation consisted of a stepwise attempt to directly cross the occluded segment employing different guidewires. Anterograde dissection and reentry was defined as an anterograde PCI, during which the operator intentionally used the subadventitial space to partially or totally overcome the CTO segment with gears, reentering into the true lumen distally to the CTO. A retrograde procedure was defined as an attempt to cross the lesion through a collateral vessel supplying a segment distal to the target CTO. We defined technical success as successful CTO revascularization within the treated segment, restoration of Thrombolysis in Myocardial Infarction anterograde flow grade 3, and residual stenosis <30%. Procedural success was the achievement of technical success without major adverse cardiac and cerebrovascular events (MACEs). Outcomes of in-hospital MACEs before hospital discharge included all-cause mortality, myocardial infarction (MI), and stroke. MI was defined using the universal definition of MI (type 4a MI). Stroke was defined as a new focal neurologic deficit of sudden onset of presumably cerebrovascular irreversible cause (or resulting in death) within 24 hours and not caused by any other easily identifiable cause. Procedural complications included major bleeding, coronary perforation, cardiac tamponade, and urgent revascularization with PCI or coronary artery bypass graft (CABG). Major bleeding was defined as any bleeding causing a reduction in hemoglobin >3 g/100 ml or bleeding requiring transfusion or surgical intervention. Coronary perforation was defined following Ellis’ classification. Cardiac tamponade was defined as a hemodynamic compromise caused by an acute accumulation of blood in the pericardial space.
The investigated predictive success scores were the Multicenter CTO Registry in Japan (J-CTO, 2011 ), the Clinical and Lesion-related Score (CL-score, 2015 ), the Ostial location, Rentrop grade, and Age (2016 ), the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO, 2016 ), and the EuroCTO Score (CASTLE, 2019 ). For comparison, technical success, as described in the article, was used as the target outcome for all scores. The grades of each score were categorized into easy, intermediate, difficult, and very difficult, as depicted in Figure 1 . The cut-off points for these categories were derived from the original publications, except for the PROGRESS score, for which the cut-off points were defined by consensus among the authors of this article because of the lack of description in its original publication and no reference in the literature.
In addition, we analyzed the Outcomes, Patient health status, and Efficiency iN Chronic Total Occlusion hybrid procedures (OPEN-CTO), OPEN-CLEAN perforation score, the PROGRESS-CTO MACEs, the PROGRESS-CTO mortality, and the PROGRESS-CTO pericardiocentesis. The outcome for the comparison between OPEN-CLEAN and PROGRESS-CTO pericardiocentesis was the occurrence of Ellis grade 3 perforation or tamponade. The performance of the PROGRESS-CTO MACE score was assessed for the composite outcome of death, MI, stroke, unplanned revascularization (percutaneous or surgical), Ellis grade 3 perforation, or tamponade during the index hospitalization. Lastly, the PROGRESS-CTO mortality score was evaluated based on the outcome of death from any cause during the index hospitalization.
Continuous variables were expressed as mean ± SD or median (interquartile range), according to data normality. The normality of the distribution of each variable was assessed by the Shapiro–Wilk test. Categorical variables were expressed as relative and absolute frequencies. Continuous variables were compared using independent samples Student’s t test or Mann–Whitney U test. Receiver operating characteristic curves were used to evaluate the discriminatory power of the different scores. A Youden index analysis was performed to determine the best cut-off value for predicting clinical end points. The areas under the curve (AUCs) were compared using the De Long test. Sensitivity, specificity, and positive and negative predictive values were calculated for the Youden index values. The Hosmer–Lemeshow goodness-of-fit test was used to assess the calibration of the scores. Inter-rater reliability between multiple observers was assessed using the intraclass correlation coefficient. Scores were categorized into different categories (easy, intermediate, difficult, and very difficult) for direct comparison. The intraclass correlation coefficient statistic was calculated based on a 1-way random-effects model, treating the raters as a random factor. Statistical analysis was performed with MedCalc Statistical Software version 14.8.1 (MedCalc Software bvba, Ostend, Belgium) and IBM SPSS Statistics Version 29.0 (IBM Corporation, Chicago, Illinois). A 2-tailed p <0.05 was considered statistically significant.
Results
A total of 3,706 procedures included in the LATAM CTO Registry from April 2008 to December 2023 were analyzed. Of these, 2,835 procedures had sufficient information for analyzing the J-CTO, PROGRESS, Rentrop grade, and age (ORA), CL-score, and CASTLE success scores. The distribution of cases among countries was as follows: Brazil 47.6%, Mexico 17.6%, Argentina 16.8%, Colombia 7.2%, Puerto Rico 6.2%, Chile 3.8%, Ecuador 0.25%, and Bolivia 0.1%. The mean value of procedure per operator was 25; 89 operators (82%) had <10 procedures per year and 83 operators (77%) had <5 procedures per year.
The overall success rate was 86%. Contralateral injection was used in 58% of the procedures and microcatheter in 85%. The main strategy for success was anterograde wire escalation (80%), followed by anterograde dissection reentry and retrograde techniques, with approximately 10% each. The percentage of retrograde technique use was 15%. The median fluoroscopy time was 34 minutes, and the average contrast volume was 245 ml. The access routes were the following: radial-femoral (30%), single radial (24%), femoral-femoral (20%), single femoral (17%), and radial-radial (6%). The main study sample baseline characteristics are listed in Table 1 .
| Overall n = 2834 | Failure n = 387 | Success n = 2447 | p-value | |
|---|---|---|---|---|
| Age | 63.7 (± 10.5) | 65.8 (±10.8) | 63.4 (±10.5) | <0.001 |
| Male Sex | 2204 (77.8) | 297 (76.7) | 1907 (77.9) | 0.601 |
| BMI | 27.8 (±4.1) | 27.7 (±4.0) | 27.8(±4.1) | 0.421 |
| LVEF | 52 (±12.3) | 52(±12.9) | 53 (±12.2) | 0.327 |
| CHF | 452 (16.0) | 57 (14.7) | 395 (16.2) | 0.472 |
| Prior CABG | 386 (13.6) | 78 (20.2) | 308 (12.6) | <0.001 |
| Prior MI | 1326(46.8) | 191 (49.4) | 1135 (46.4) | 0.273 |
| Prior PCI | 1295 (45.8) | 203 (52.6) | 1092 (44.7) | 0.004 |
| Diabetes | 1148 (40.6) | 154 (40) | 994(40.7) | 0.794 |
| PVD | 272 (9.7) | 41 (10.7) | 231 (9.6) | 0.496 |
| CKD | 217 (7.7) | 27 (7.0) | 190 (7.8) | 0.580 |
| Current Smoking | 549 (19.6) | 73 (19.1) | 476 (19.7) | 0.792 |
| Target vessel | ||||
| -LAD | 1066 (37.6) | 117 (30.2) | 949 (38.8) | 0.001 |
| -RCA | 1146 (40.4) | 181 (46.8) | 959 (39.4) | 0.006 |
| -LCX | 608 (21.4) | 85 (22.0) | 523 (21.4) | 0.789 |
| Ostial lesion | 525 (18.5) | 86 (22.2) | 439 (17.9) | 0.044 |
| Occlusion Length | 20 [15-30] | 25 [20-30] | 20 [15-28] | <0.001 |
| Blunt Proximal cap | 1292 (45.6) | 273 (70.5) | 1019 (41.6) | <0.001 |
| Moderate or severe calcification | 1279 (45.1) | 229 (59.2) | 1050 (42.9) | <0.001 |
| Proximal cap ambiguity | 903(31.9) | 212 (54.8) | 691 (28.2) | <0.001 |
| Moderate or severe tortuosity | 482 (17.0) | 95 (24.5) | 387 (15.8) | <0.001 |
| No interventional collaterals | 1084 (38.2) | 140 (36.2) | 944 (38.6) | 0.112 |
| Collaterals | 0.917 | |||
| -No continuous connections | 597 (21.1) | 83 (21.4) | 514 (21.0) | |
| -Continuous threadlike connections | 1496 (52.8) | 206 (53.2) | 1290 (52.7) | |
| -Side branch like collateral | 742 (26.2) | 98 (25.3) | 644(26.3) | |
| In-stent restenosis | 348 (12.3) | 43 (11.1) | 305(12.5) | 0.435 |
| Prior attempt | 377 (13.3) | 77 (19.9) | 300(12.3) | <0.001 |
| Retrograde procedure | 420 (15.6) | 150 (34.4) | 270 (12.0) | <0.001 |
| Success Scores | ||||
| J-CTO | 2[1-3] | 3[2-4] | 2[1-3] | <0.001 |
| Castle | 2[1-2] | 2[2-3] | 2[1-2] | <0.001 |
| Progress | 1[0-2] | 1[1-2] | 1[0-2] | <0.001 |
| ORA | 1[1-1] | 1[1-2] | 1[1-1] | 0.001 |
| CL-SCORE | 2.5 [2-3.5] | 3.5 [2.5-5] | 2.5[1.5-3.5] | <0.001 |
| Complication Scores | ||||
| Progress MACE | 2[1-3] | 3 [2-4] | 2 [1-3] | <0.001 |
| Progress Pericardiocentesis | 1[1-2] | 2 [1-3] | 1 [1-2] | <0.001 |
| Progress Mortality | 1 [1-2] | 1 [2-3] | 1 [1-2] | <0.001 |
| OPEN-CLEAN | 2 [2-3] | 3 [2-4] | 2 [2-3] | <0.001 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
