Chronic Total Occlusion Procedures Research Articles

Nonrigid 2D/3D Registration of Coronary Artery Models With Live Fluoroscopy for Guidance of Cardiac Interventions

A 2D/3D nonrigid registration method is proposed that brings a 3D centerline model of the coronary arteries into correspondence with bi-plane fluoroscopic angiograms. The registered model is overlaid on top of interventional angiograms to provide surgical assistance during image-guided chronic total occlusion procedures, thereby reducing the uncertainty inherent in 2D interventional images. The proposed methodology is divided into two parts: global structural alignment and local nonrigid registration. In both cases, vessel centerlines are automatically extracted from the 2D fluoroscopic images, and serve as the basis for the alignment and registration algorithms. In the first part, an energy minimization method is used to estimate a global affine transformation that aligns the centerline with the angiograms. The performance of nine general purpose optimizers has been assessed for this problem, and detailed results are presented. In the second part, a fully nonrigid registration method is proposed and used to compensate for any local shape discrepancy. This method is based on a variational framework, and uses a simultaneous matching and reconstruction process to compute a nonrigid registration. With a typical run time of less than 3 s, the algorithms are fast enough for interactive applications. Experiments on five different subjects are presented and show promising results.

In-hospital outcomes of percutaneous coronary intervention in patients with chronic total occlusion: insights from the ERCTO (European Registry of Chronic Total Occlusion) registry

In comparison with non-occlusive lesions, percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) represents a greater challenge for the interventionalist, due to lower procedural success rates, relatively higher incidence of procedural complications and the increased rate of restenosis. The European Registry of Chronic Total Occlusion (ERCTO) was created with the goal of evaluating the real impact of CTO PCI in the European context, trying to analyse the rates of procedural success, technical information from the CTO procedures and patient outcome. Data collection was carried out in 16 centres across Europe, starting from the beginning of January 2008. In two years of activity, a total of 1,914 patients with 1,983 CTO lesions were consecutively enrolled in the registry. Overall procedural success was achieved in 1,607 lesions (82.9%); anterograde procedures obtained higher procedural success of retrograde ones (83.2% versus 64.5%, p<0.001). Coronary perforation occurred more frequently in patients who underwent retrograde approach (4.7% versus 2.1%, p=0.04). Although no differences were observed in terms of 30-day major adverse cardiac events between anterograde and retrograde treated patients, a trend toward higher periprocedural non-Q-wave myocardial infarction was found in patients in which the retrograde approach was attempted (2.1% versus 1% p=0.08). Moreover, retrograde approach was related with longer procedural and fluoroscopy times (156.9±62.5 min vs. 98.2±52.8 min and 73.3±59.9 min vs. 38.2±43.9 min respectively, p<0.001) and higher contrast load administration (402±161 cc vs. 302±184 cc, p<0.001). The first report of the ERCTO registry by the EuroCTO club shows a high procedural success rate obtained by expert European operators in a "real-world" consecutive series of patients, comparable with those reported by Japanese registries. The rate of observed procedural adverse events was low and similar to the non-CTO PCI series. In this registry, retrograde procedures were associated with extended fluoroscopy exposure and procedural time, increased contrast load administration as well as a higher incidence of coronary perforations. Such outcomes should become the standard of care that all centres undertaking CTO PCI should aspire to.

35 Successful recanalisation of chronic total occlusions is associated with increased long term survival

<h3>Introduction</h3> Chronic total occlusion (CTO) remains a challenging lesion subset. Despite advances in equipment and expertise, many CTO patients may not be offered PCI as physicians perceive procedural success may be lower, and the anatomy is stable. The aim of this study was to investigate the impact of procedural success on mortality following CTO-PCI in a large cohort of patients in the drug eluting stent era. <h3>Methods</h3> 6122 consecutive patients underwent elective PCI at a single centre (October 2003–May 2010), 836 (13.7%) for CTO. Demographic and procedural data were collected at the time of intervention (Abstract 35 table 1). In-hospital MACE (myocardial infarction, urgent revascularisation, stroke or death) was documented at discharge. All cause mortality data was obtained from the Office of National Statistics via the BCIS/CCAD national audit out to 4 years (mean 2.9±1.6) and stratified according to successful or unsuccessful CTO recanalisation. <h3>Results</h3> 572 (68.4%) CTO procedures were successful. Coronary stents were implanted in 96.9% (mean 2.3±0.1 stents per patient, 70% drug eluting). Prior revascularisation was more frequent among patients with unsuccessful CTO-PCI than successful; prior CABG 16.5% unsuccessful vs 7.4% successful, (p&lt;0.0001), PCI 36.0% vs 21.2%, (p&lt;0.0001). Baseline characteristics were otherwise similar (Abstract 35 table 1). Intra-procedural complications (coronary dissection, perforation, access site (dissection, haematoma) were more frequent in unsuccessful cases (19% (52) vs 4.1% (20) (p&lt;0.0001) but did not have an impact on in-hospital MACE (2% vs 1.8%, p=0.6). All cause mortality was 8% (21) in the unsuccessful group and 3% (17) in the successful group out to 4 years, (Abstract 35 figure 1). Mortality following successful CTO-PCI was similar to that of the non-CTO elective PCI group (5.1%, p=NS). <h3>Conclusion</h3> A successful angiographic outcome following CTO-PCI is associated with a survival advantage out to 4 years following intervention. These data suggest that the adoption of new techniques and technologies to improve procedural success may improve prognosis.

Chronic total occlusion special issue

Since its pioneering years, interventional cardiol­ ogy has faced the hurdle of dealing with the spe­ cial case of chronic total occlusion (CTO). Long considered to be the ‘last frontier’ of percutane­ ous coronary interventions, it is only in the last decade that we have finally observed a significant breakthrough in this challenging field, mostly owing to new techniques and materials coming from Japan. Chronic total occlusion procedures now con­ stitute approximately 10–20% of all angio plasty operations at high­volume hospitals [1]. Advances, mainly in guidewire technology, and the develop­ ment of new techniques have increased success rates up to an astounding 90% in specialized cent­ ers with experienced operators [2]. Concomitantly, a reduction of the CTO restenosis rate has been observed with the advent of drug­eluting stents [3]. New data have also highlighted the clinical benefits of CTO revascularization, which, in addition to angina relief, include improvement of left ventricular function, a reduction of major adverse cardiac events and perhaps increased sur­ vival rates [4]. However, an important hurdle on the road to wider utilization of CTO revascu­ larization is that these are long, expensive pro­ cedures that expose the operators to high doses of radiation. A particularly steep learning curve also exists. Complexity of procedures and limited familiarity with new techniques may often lead to premature interruption of procedures, causing both physician and patient frustration and rep­ resenting a common reason for referral to bypass surgery or for choosing medical treatment. Strict adherence to recently developed guidelines [5], especially concerning patient selection, equip­ ment, facilities and proctoring, is thus, in our opinion, essential for an adequate set­up and maintenance of a successful CTO program. Recent advances in CTO techniques that have broadened percutaneous coronary intervention indications and improved success rates can be categorized into anterograde and retrograde approaches [6]. In the presence of visible con­ tralateral collaterals, operators now widely use bilateral injections to allow for simultaneous anterograde and retrograde filling of the target vessel. Anterograde, parallel wire, controlled dissection and microchannel penetration tech­ niques have been developed [7]. Techniques for retrograde penetration of the distal CTO cap are various, with the controlled anterograde and retrograde tracking [8], especially in its ‘reverse’ variety, being particularly popular. However, no consensus exists for s election of the initial approach to a CTO.

Transradial approach for percutaneous coronary interventions on chronic total occlusions

The transfemoral approach is the standard approach for performing chronic total occlusion procedures. However, hemorrhagic and vascular entry site complications are known to be reduced by the adoption of the transradial approach. Thus, the transradial approach is gaining interest and, facilitated by the improvement of materials and techniques, will be applied in procedures previously considered possible only by femoral access. In this article, we review the data regarding the feasibility and safety of the transradial approach for chronic total occlusion percutaneous coronary interventions and provide an overview of the technical aspects useful for performing chronic total occlusion by radial access.

Crossing CTOs—The tips, tricks, and specialist Kit that can mean the difference between success and failure

Percutaneous coronary intervention (PCI) for chronic total occlusions (CTO) remains one of the major challenges in interventional cardiology. The appropriate use of the rapidly increasing range of tools available to interventional cardiologists is bringing more and more CTOs into the 'treatable' category. The bar has now been raised to 80% success rates by some expert operators around the world, which, in our view, cannot be achieved without a thorough understanding of technique and technical know-how. CTO procedures are increasingly becoming a sub-specialist field within interventional cardiology and we would encourage centers to consider appointing 'super-specialists' who are able to concentrate experience and expertise in this area. In this paper we detail the principal characteristics of the over the wire balloons, microcatheters and guidewires at present available, the most popular and recent of which are listed in Table 1 and 2. The knowledge and the specific choice of these materials and the criteria for selection of your guidewire or microcatheter can mean the difference between success and failure. Moreover, we discuss on the most important and groundbreaking techniques to approach a CTO. Finally, considering the greater risk of coronary perforation related to a CTO procedure compared to routine PCI, we describe which are best strategy and devices for treating coronary perforations and other major complications.

The Efficacy of a Bilateral Approach for Treating Lesions With Chronic Total Occlusions: The CART (Controlled Antegrade and Retrograde subintimal Tracking) Registry

The aim of this study was to evaluate the safety and feasibility of a new concept for chronic total occlusion (CTO) recanalization-using a bilateral approach that utilizes a Controlled Antegrade and Retrograde subintimal Tracking (CART) technique. Successful percutaneous recanalization of coronary CTOs results in improved long-term outcomes. The recanalization of CTOs in native coronary arteries no doubt represents one of the most technically challenging of interventional procedures. A total of 224 consecutive patients (mean age 61 +/- 9 years; 86.2% men) were enrolled in this prospective multicenter registry. This technique combines the simultaneous use of antegrade and retrograde approaches. A subintimal dissection is created in both antegrade and retrograde fashion, thereby limiting the extension of the subintimal dissection within the CTO portion. Of 224 CTO lesions (>3 months in duration) undergoing attempted recanalization using the CART technique, 145 cases (64.7%) had undergone previous CTO recanalization attempts. The success rates of crossing in a retrograde fashion with a wire and a balloon were 87.9% and 79.9%, respectively. The overall technical and procedural success rates achieved in this registry were 92.4% and 90.6%, respectively. A bilateral approach for CTO lesions using the CART technique is feasible, safe, and has a higher success rate than previous approaches. These results indicate that a bilateral technique can solve a major dilemma that commonly affects CTO procedures.

Percutaneous coronary intervention for chronic total occlusions: Improved survival for patients with successful revascularization compared to a failed procedure

There are limited data on the impact of successful chronic total occlusion (CTO) revascularization by percutaneous coronary intervention (PCI) on survival. We performed a retrospective study comparing the survival between patients with a successful and a failed CTO revascularization by PCI. Between January 1, 2000 and June 30, 2004, 543 of 5803 (9.4%) patients underwent PCI for a CTO at our center. A CTO was defined as an occlusion of the artery present for at least 3 months with Thrombolysis in Myocardial Infarction flow grade 0 or 1. Patient records were linked to a national database to monitor all deaths during follow up. Propensity matching was used to balance out case mix differences. Technical success for CTO was 377 of 543 (69.4%). In-hospital mortality was 0.3% and 1.2% for the CTO success and CTO failure patients, respectively. During a mean (SD) follow up of 1.7 (0.5) years, the mortality rate was 2.5% in the CTO success patients and 7.3% in the CTO failure patients. The crude hazard ratio for death with CTO failure was 3.92 (95% confidence intervals 1.56-10.07; P = 0.004). The rates of coronary artery bypass were 3.2% vs. 21.7% (P < 0.001) for the CTO success and CTO failure patients, respectively. Our propensity matched 157 CTO success to CTO failure patients and the associated hazard ratio for death with CTO failure was 4.63 (95% confidence interval 1.01-12.61; P = 0.049). Multivariate analysis showed that CTO failure was an independent predictor of death. Patients with a successful revascularization of a CTO by PCI have an increased survival rate compared to patients with a failed CTO procedure.

Three dimensional cortical surface morphometry and metabolism using registered magnetic resonance and position emission images

Although intraprocedural coronary computed tomographic angiography (CCTA) allows for scanning during intervention without relocation of the patient, studies have yet to report on its use during chronic total occlusion (CTO) intervention. Therefore, we investigated the role of CCTA during CTO intervention, particularly whether CCTA could be used to evaluate the location of guidewires. A total of 61 patients scheduled for elective CTO intervention were consecutively enrolled and underwent CCTA and on-site analyses during intervention. Transverse axial and the curved multiplanar images in a 360-degree view were interactively used together to identify the location of guidewires, along with the adjustment of window condition. Intracoronary contrast injection was used for specific cases requiring enhancement of the distal part of the CTO. Most CCTAs were performed to confirm the location of a single guidewire; CCTA was also performed to evaluate parallel (3 patients) or retrograde wires (5 patients). The initial identification rate for guidewire location was 56% with immediate transaxial images, but it significantly increased to 87% after interactive on-site uses of the curved multiplanar images (p <0.001). Cases in which guidewire location could be predicted with CCTA evaluation show a numerically higher success rate than those that could not (83% vs 63%) but not statistical significance (p = 0.174). The mean time for CCTA evaluation and mean radiation dose were 8.6 minutes and 2.9 mSv, respectively. No specific complications occurred after CCTA and CTO procedures. Intraprocedural CCTA for identifying the location of the guidewires is feasible and safe when used for various CTO procedural steps.