The CIBELES trial (Clinicaltrials.gov identifier NCT00793221) included 207 patients with a coronary CTO with an estimated duration of occlusion >2 weeks.7,8 The patients were randomly allocated to everolimus-eluting (Xience V, Abbott Vascular) or sirolimus-eluting (Cypher, Cordis, Johnson & Johnson) coronary stents. In the latest guidelines on the treatment of CTO, CTO was defined as a total occlusion with an estimated duration of occlusion >3 months. However, in the CIBELES study an estimated duration of occlusion >2 weeks was used, for two reasons. First, most studies comparing different strategies to reduce restenosis in CTO included patients with an estimated duration of occlusion >2 weeks. Second, in the CIBELES study, two different types of drug-eluting stents were compared, taking late loss as the primary endpoint, and duration of occlusion has more impact on the probability of crossing the occlusion than on the risk of restenosis. Despite these two considerations, estimated duration of occlusion in the CIBELES study was >3 months in 80% of cases.8 Other inclusion and exclusion criteria have been previously published.7

Thirteen centers in Spain and Portugal participated in the study, all of them with a high volume of percutaneous coronary interventions on CTO. The Spanish Society of Cardiology sponsored the study, which was partly funded by an unrestricted grant from Abbott Vascular. The study was monitored by Chiltern International, and had an independent clinical events committee.

For every patient, data were collected on approach (anterograde or retrograde, femoral or radial), material and techniques used (types of guidewires, balloons, microcatheters, intravascular ultrasound, rotational atherectomy, etc.), type of anticoagulation and amount of contrast. All these aspects were left to the operators’ discretion, respecting local practice, and hence the data obtained reflect standard practice in each center.7

The statistical analysis was performed with SPSS version 12.0 (SPSS Inc., Chicago, IL, USA). Continuous variables are presented as mean±standard deviation, and qualitative variables as proportions (percentages). Means were compared with the Student's t test, and proportions were compared using the chi-square test (with Fisher's correction when necessary). Differences were considered statistically significant with a p value <0.05.

In order to evaluate variability between different participating centers, the variation coefficient was calculated for different study variables (standard deviation/mean).

The patients’ mean age was 64±10 years, and 83% were male. About 36% of patients were diabetic. Due to the inclusion criteria, all treated lesions were de novo and located in native vessels. The treated vessel was the left anterior descending artery, right coronary artery, and left circumflex artery in 41%, 39%, and 19%, respectively.

A radial approach was used in 23% of cases; a retrograde approach was used in only 5% of patients. The use of radial (0%-92%) and retrograde approaches (0%-18%) both showed considerable variability between participating centers (Figure 1).

Figure 1.

Proportions of patients treated with different material, devices and techniques in each participating center.

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The mean number of guidewires used was 2.0±1.2. Asahi guidewires were the most frequently used (34.6%), followed by Abbott (21.2%) and Terumo (10.6%) guidewires. In 33.8% of cases, guidewires specifically designed for CTO were not used.

A large number of balloons (2.2±0.9 per patient) were used. Of these balloons, most were pre-dilatation balloons (1.9±0.7 per patient). Post-dilatation balloons were used in only 25% of patients, the number used per patient being 0.3±0.4. Microcatheters were used in 33% of patients (74 in 68 patients), the most frequent type being Finecross (Terumo) (77%), followed by Corsair (Asahi) (16%). Due to the study design, all patients received drug-eluting stents. The mean number of stents implanted per patient was 2.1±1.0, with a mean stent length of 49±24 mm.

Other devices and techniques used were Tornus penetration catheters (Abbott Vascular) in 4% of patients, rotational atherectomy (Boston Scientific) in 2%, and cutting balloon (Boston Scientific) in 1%. Importantly, intracoronary ultrasound during the procedure or after stent implantation was used in only 6% of procedures, also with considerable variability between participating centers (Figure 1).

Antiplatelet therapy consisted of aspirin and clopidogrel in all patients. Additionally, 4% of patients received glycoprotein IIb/IIIa inhibitors. Anticoagulation during the procedure was performed with unfractionated heparin in most cases (87%), followed by bivalirudin (12%) and enoxaparin (1%). In eight of the 13 centers (62%), unfractionated heparin was the only anticoagulation used.

Figure 1 shows the variability between participating centers. The greatest variability was observed in the use of intracoronary ultrasound (variation coefficient 2.14), and the least was found in the use of guidewires specific for CTO (variation coefficient 0.37).

Table 4 shows the comparison between patients with an estimated duration of occlusion >3 months and <3 months. Of the 207 patients, 165 (80%) had an estimated duration of occlusion >3 months. These patients had higher rates of specific techniques for CTO (specific guidewires, microcatheters, etc.), but the differences were statistically significant only in the use of a radial approach (20% vs. 36%; p=0.031). A retrograde approach was used in 6% of patients with duration of occlusion >3 months, compared to 0% in patients with estimated duration of occlusion of between 2 weeks and 3 months. A trend for a higher rate of use of plaque modification devices (rotational atherectomy, cutting balloon, Tornus catheter) was found in patients with >3 months since occlusion (9% vs. 0%, p=0.078).

This study has some limitations. First, the main objective of the CIBELES trial was to compare two different types of drug-eluting stents, and did not include analysis of the material and techniques used in the trial's endpoints. However, this in fact reinforces the findings related to the techniques and material used: since no specific recommendations were given in the study, the data in this article reflect the daily practice of the participating centers. Second, due to the study design, in all included patients the guidewire successfully crossed the vessel occlusion, and this may have influenced the study's results. However, we believe this may be only applicable to guidewires, and not to other devices used in CTO. Third, the centers participating in the CIBELES trial were only in Spain and Portugal, and treatment of CTO may differ in other countries. Despite these limitations, we believe that the findings probably reflect daily practice in most countries and centers treating CTO, at least in Europe and the USA.

The authors declare that the procedures followed were in accordance with the regulations of the relevant clinical research ethics committee and with those of the Code of Ethics of the World Medical Association (Declaration of Helsinki).

The authors declare that they have followed the protocols of their work center on the publication of patient data and that all the patients included in the study received sufficient information and gave their written informed consent to participate in the study.

The authors have obtained the written informed consent of the patients or subjects mentioned in the article. The corresponding author is in possession of this document.