Antegrade Dissection and Re-entry Versus Retrograde Strategy in CTO PCI

The ADRENALINE trial has been designed as a multi-center, prospective randomized study to compare the procedural and periprocedural outcomes of coronary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) using antegrade dissection and re-entry (ADR) versus retrograde strategy. Beyond the patient-oriented outcomes, the influence of the studied CTO PCI strategies on the stress levels among interventional cardiologists will be explored.

The main questions it aims to answer are as follows:

* What is the difference between ADR versus retrograde strategy with regard to total procedure time, the rates of successful guidewire crossing and periprocedural complications as well as stress levels experienced by interventional cardiologists?
* Is retrograde approach associated with higher rates of myocardial injury/infarction based on cardiac troponin/cardiac magnetic resonance (CMR) as compared with ADR?

Participants will undergo pre- and postprocedural laboratory testing (cardiac troponin, CK-MB), CMR for late gadolinium enhancement and health status assessment. Subjects undergoing successful CTO PCI using antegrade wiring strategy will be included in the observational arm.

The ADRENALINE trial is planned as a multicenter, prospective randomized research experiment in patients with clinical indication for PCI of CTO. The target population will comprise patients with at least difficult CTO (J-CTO score ≥2) and angiographic equipoise for either ADR or the retrograde CTO recanalization strategy as evaluated by 2 independent CTO PCI operators. The pre-procedural assessment will comprise cardiac magnetic resonance (CMR) for late gadolinium enhancement, laboratory testing (cardiac troponin, creatine kinase-MB) and health status assessed by the Seattle angina questionnaire (SAQ) and the Rose Dyspnea Scale. Subsequently patients with either failed or unattempted primary antegrade wiring strategy will be evenly randomized (1:1 fashion) to either ADR or the retrograde CTO crossing strategy. After CTO PCI, the cardiac troponin and creatine kinase-MB will be measured at 12 hours intervals (at least up to 24 hours), while CMR with late gadolinium enhancement will be repeated within 5 days post-procedure. The health status of the study participants (SAQ and the Rose Dyspnea Scale) will be re-assessed at 3-months post-CTO PCI. In addition, to investigate the effect of the studied CTO PCI strategies on the occupational hazard of interventional cardiologists, the physical and mental stress levels experienced by CTO operators will be continuously monitored during the procedure. The co-primary endpoint is defined as: 1) total procedure time and 2) successful guidewire crossing through CTO. The secondary endpoints include: time of successful guidewire crossing through CTO, final technical success of CTO PCI, radiation dose, contrast volume, equipment cost, procedural complications, rate of periprocedural myocardial injury, rate of new myocardial infarction on CMR, quality of life, target lesion failure (cardiac death, target vessel-related myocardial infarction, and clinically-driven target lesion revascularization) at 3 months follow-up, and stress indices experienced by physicians during the procedure.

Eligibility Criteria:
Inclusion Criteria:

* clinical indication for CTO PCI as determined by the local heart team (presence of angina or equivalent symptoms and/or documented ischemia or viability)
* at least difficult native CTO lesion with J-CTO difficulty score ≥2 points on invasive angiography
* angiographic suitability for both ADR and the retrograde strategy as assessed by 2 independent hybrid CTO PCI operators
* informed consent for participation in the study

Exclusion Criteria:

* \<18 years of age
* acute myocardial infarction
* cardiogenic shock
* severe valvular disease
* estimated life expectancy \<1 year
* contraindication to PCI
* contrast allergy
* positive pregnancy test or breast-feeding
* native CTO lesion with easy or intermediate difficulty score on invasive angiography (J-CTO score \<2 points)
* lack of angiographic equipoise between the ADR and the retrograde strategy as assessed by 2 independent hybrid CTO PCI operators