Antegrade and Retrograde Dissection and Re-entry Approach for CTO
Condition: Chronic Total Occlusion of Coronary Artery
Study type: Interventional

Summary: 
      BACKGROUND：Chronic total occlusion (CTO) angioplasty is one of the most challenging
      procedures remaining for the interventional operator. Today, with contemporary CTO
      negotiation available strategies and significant operator expertise, the literature reports a
      50%-95% success rate for recanalizing CTOs. But PCIs of CTO lesions still carry a high rate
      of in-stent restenosis (ISR). Because previous reports have not specifically compare
      contemporary antegrade and retrograde dissection and re-entry dissection (ADR/RDR) technique
      on the long-term impact of ISR, so the investigators focused on the objective.

      OBJECTIVES: This study hope to evaluate the frequency of angiographic ISR and further
      elucidate some ISR related higher risk factors among CTO PCI patients in intimal stent group
      using antegrade or retrograde wire escalation (AWE/RWE) techniques and sub-intimal stent
      group using contemporary antegrade or retrograde dissection and re-entry (ADR and/or RDR).

      METHODS: A total of 300 consecutive selected patients with CTO lesion who will undergo
      successful revascularization by AWE/RWE and ADR/RDR techniques treatment will be enrolled in
      this prospective multicenter registry from December 1 2018 to December 31 2019. The primary
      study endpoint of the protocol is the bionary in-stent restenosis of CTO vessels at
      angiographic follow-up about 13 months. The secondary endpoints are: 1) CTO technique and
      procedure success rate; and 2) in-hospital and 30 days MACE (Cardiac death, acute myocardial
      infarction, urgent repeat tratget vessel revascularization with either pericardiocentssis or
      surgery and stroke and stent thrombosis and stroke); 6months and 1-year and 2-year MACE
      including death, MI, and target CTO vessel revascularization and stroke ; and 3) Restenosis
      scores (R-scores) of related risk factors.
    

Detailed description: 
      METHODS

        1. Trial overview and study population.

           ① This clinical trial is a prospective, exploratory, nonrandomized, multicenter trial
           evaluating the frequency of angiographic restenosis and clinical outcomes among patients
           undergoing CTO PCI in intimal stent group using antegrade or retrograde wire escalation
           (AWE/RWE) techniques and sub-intimal stent group using contemporary antegrade or
           retrograde dissection and re-entry (ADR or RDR) with everolimus-eluting stents (XIENCE
           Coronary Stent).

           ②According to high patient's volume registry studies in CTO lesions, the patients
           percentage of ADR or RDR strategy application was just only 20-25%36-37. If to get 60
           patients for ADR or RDR strategies, the minimum CTO number are 300 patients. So in this
           registry study, 300 CTO cases, to which PCI will be attempted, are prospectively
           enrolled from Dec 1st 2018 to Dec 31st 2019 in the CTO registries of ten centers. The
           study was approved by the institutional review board at each site. For patients with
           multiple treated CTO, only the first CTO attempted was considered for the analysis.

           ③ Exclusions included age <18-years-old or >85-years-old, left ventricular ejection
           fraction ≦30%, allergy to medications (antiplatelet drugs, heparin, metal alloys, or
           contrast agents), a planned surgery within 6 months of PCI or planned thrombolysis,
           pregnant, a life expectancy of <6 months.

           ④ Participants will sign written informed consent for long-term telephone FU before the
           interventional procedure. Participants will be followed by a clinical visit or by a
           telephone interview for 30 day, 6 months and 12 months and 24 months post-procedure for
           assessment of adverse events. All patients with successful CTO PCI and without moderate
           or severe renal insufficiency will be scheduled for angiographic follow-up at 13 months.
           Compared with CTA, coronary angiography to evaluate restenosis is appropriate in all
           patients especially for severe coronary heart diseases patients with atrial fibrillation
           and ventricular arrhythmia. It could provide accurate information about mild-severe
           angulation lesion and the stents traits like total stent length. Procedural and outcome
           data collection will be collected and entered by operators entered into a dedicated
           database.

           ⑤ The study will be performed in accordance with the Declaration of FMMU.

        2. Study endpoints and definitions The primary study endpoint of the protocol is the
           bionary in-stent restenosisof CTO vessels at the scheduled angiographic follow-up at 13
           months. The secondary endpoints are: 1) CTO technique and procedure success rate; and 2)
           in-hospital and 30 days MACE (Cardiac death, acute myocardial infarction, urgent repeat
           tratget vessel revascularization with either pericardiocentssis or surgery and stroke
           and stent thrombosis and stroke); 6 months and 1-year and 2-year MACE including death,
           MI, and target CTO vessel revascularization and stroke ; and 3) Restenosis scores
           (R-scores) of related risk factors.

      Coronary CTOs will be defined as angiographic evidence of total occlusions with TIMI
      (Thrombolysis In Myocardial Infarction) flow grade 0 and estimated durations of at least 3
      months. Estimation of the occlusion duration is based on first onset of anginal symptoms,
      prior history of myocardial infarction in the target vessel territory, or comparison with a
      prior angiogram.

      Procedural success will be defined as angiographic success(final residual stenosis <30% by
      visual estimation and TIMI flow grade 3 after CTO recanalization).

      Clinical success will be defined as a procedural success without In-hospital MACCEs.
      In-hospital MACCEs is defined as the composite of non-Q-wave and Q-wave myocardial infarction
      (MI), recurrent angina requiring urgent repeat revascularization with PCI orcoronary bypass
      surgery, stroke, and death. Non-Q-wave MI is defined as creatine kinase-MB enzyme elevation
      >3 times the upper limit of normal. When new pathological Q waves, in addition to enzyme
      elevation, will be observed on the electrocardiogram, the event is defined as a Q-wave MI. In
      all patients, creatine kinase and creatine kinase-MB is evaluated 6 h after the procedure and
      until their normalization if levels is abnormal.

      Lesion complexity will be judged using the J-CTO (20)and calculated by allocating 1 point
      each for non-tapered proximal cap (ie, blunt or ambiguous), any calcification, any
      tortuosity, occlusion length >20 mm and any prior unsuccessful attempt. J-CTO score of ≥2 was
      defined as complex.

      CTO proximal cap location is defined according to American Heart Association (AHA)
      classification and additionally coded as either ostial or non-ostial and proximal (left main,
      proximal left anterior descending, proximal circumflex or proximal right coronary artery) or
      distal (all other sites). Cap morphology is coded as blunt or tapered, or as ambiguous when
      there is lack of clarity over the origin of the ongoing vessel. Calcification within the CTO
      is coded as none visible, mild(spots only), moderate (<50% of vessel circumference) or severe
      (>50% of vessel circumference). Disease proximal and distal to the CTO is classified as
      absent, mild, moderate or severe. Aproximal or distal cap side branch is considered present
      if occurring ≤3 mm from the respective CTO cap. Occlusion length is estimated by dual
      injection, or from apparent length after guidewire crossing. Collaterals are classified
      according to Cohen and Rentrop and deemed interventional if, on angiographic inspection, are
      thought amenable to crossing by a guidewire and a microcatheter by the operator.

      All deaths are considered cardiac unless otherwise documented. Stent thrombosis is defined
      according to the Academic Research Consortium criteria (13). Reocclusionis defined as a TIMI
      flow grade of 0 to1in the target CTO vessel, where restenosis is defined as > 50% luminal
      narrowing at the segment site, including the stent and 5 mm proximal and distal to the stent
      edges. Target lesion revascularization (TLR) is defined as any repeat PCI or coronary artery
      bypass graft surgery of the target lesion that includes 5 mm proximal and distal to the
      stented vessel segment.

      A procedure is considered retrograde if an attempt is made to cross the lesion through a
      collateral vessel supplying the target vessel distal to the lesion. Complex lesions with
      unclear location of the proximal cap or with poor distal target are initially attempted by
      the retrograde approach. In those cases, after positioning of a microcatheter at the distal
      CTO cap, a true-to-true retrograde lumen crossing technique is first attempted for shorter
      lesions (<20 mm). When entering in the subintimal space or with longer lesions, knuckled
      wires are used to reach the proximal cap, followed most often by reverse-controlled
      anterograde and retrograde re-entry techniques.

      A procedure is considered antegrade if no retrograde crossing attempts are made. An
      anterograde approach is initially attempted for short lesions (<20 mm) with clear proximal
      cap location and good distal vessel target using a wiring strategy. Anterograde
      dissection/re-entry using dedicated devices (CrossBoss and Stingray catheters) is, however,
      preferred for longer lesions with an optimal distal re-entry zone, without significant side
      branches that could be occluded by the technique, or when an initial wire escalation strategy
      failed. Wire-based anterograde dissection/re-entry was also used successfully when an initial
      attempt at crossing from a "true-to-true" approach failed. Such a strategy involves the use
      of a microcatheter delivered on a knuckled polymer-jacketed wire advanced into the subintimal
      dissection plane, with subsequent re-entry into the true distal lumen using a stiff tapered
      guidewire or a knuckled guidewire. A Stingray system will be used to cross from the false
      lumen to the true lumen, the so-called hybrid procedure, rapidly switching from one approach
      to another when the initial strategy attempted is failing.
    

Intervention name(s): chronic total occlusion
Intervention type(s): Device
Intervention description(s): chronic total occlusion of coronary atery was opened and then stents were placed
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment