The successful re-opening of a blocked coronary artery has a beneficial effect on the further clinical course (e.g. improvement of clinical symptoms, improved quality of life, increased heart function, etc.). However, some types of blockages are more difficult to open by means of percutaneous coronary intervention (PCI), a procedure which is commonly used for these kind of problems. This procedure makes use of a technique in which special wires, balloons, stents (metal or polymeric tube-like structures) and devices are utilized to re-open or revascularize a blockage in one of the blood vessels of the heart. This type of blockages are chronic total occlusions (CTO). CTOs have certain characteristics which impede the revascularization of the blood vessel.

Nevertheless, remarkable progress has been achieved over the past few years in the area of CTO revascularization or CTO PCI. A large range of CTO dedicated materials, such as guidewires, guiding catheters, devices, balloons and stents, as well as different techniques have been developed. However, at present, reluctance to open CTOs still exists, due to the indications and outcomes of percutaneous revascularization as well as the technical difficulties which commonly arise during these interventional procedures. The presence of these difficulties results in suboptimal success rates worldwide (±70-80%), despite these many innovations.

To increase these success rates and to make sure more interventional cardiologists will treat CTOs, a hybrid treatment algorithm has been developed with the materials (e.g. CrossBoss™ catheter; Bridgepoint Medical, Inc.) and techniques, currently already available. The main purpose of this study is to evaluate the efficacy and efficiency of this hybrid algorithm as well as validating the efficacy of one of the materials (CrossBoss™ catheter), used in this algorithm. To be able to do this, data concerning the patients' demographics, CTO characteristics, procedure and outcome will be collected in the form of a registry. This registry will be performed in several European centra (Belgium, the Netherlands, United Kingdom, France). Since the study will only collect data and no intervention is performed, this will be an observational study. At regular time points, the data will be checked for errors or inconsistencies. To do this, site visits will be performed at pre-defined times.

Inclusion Criteria:

• Subject shows the presence of at least one coronary chronic total occlusion (CTO), either with or without the presence of one or more other diseased coronary arteries. This CTO must be located in a native coronary artery and have a visually estimated stenosis of 100%, corresponding with Thrombolysis in Myocardial Infarction (TIMI) flow 0. Following the operators judgment, this occlusion is present for more then 3 months.
• Subject will be/is treated percutaneously for one or more CTOs via the hybrid techniques.
• Subject (or legal guardian) understands the study requirements and the treatment procedures and provides written informed consent before any study-specific procedures are performed.
• Subject is willing to comply with all protocol-required follow-up evaluation (patient will be followed during 1 month after PCI procedure to assess any complications and clinical status).

Exclusion Criteria:

• The occlusion is considered to be less than 3 months present.
• Subject is treated via PCI without application of the hybrid algorithm and/or use of the CrossBoss™ and Stingray™ technology (Bridgepoint Medical, Inc.).
• Subject is participating in another investigational clinical trial that may cause non-compliance with the protocol or confound data interpretation.
• Subject intends to participate in another investigational clinical trial that may cause non-compliance with the protocol or confound data interpretation.

Patients diagnosed with the presence of one or more chronic total occlusions (CTOs) and who will receive treatment via percutaneous coronary intervention (PCI)