Determinants of success of coronary angioplasty in patients with a chronic total occlusion: a multiple logistic regression model to improve selection of patients

Predictors of successful endovascular recanalization in patients with symptomatic nonacute intracranial large artery occlusion

BACKGROUND

Endovascular recanalization in patients with symptomatic nonacute intracranial large artery occlusion (ILAO) has been reported to be feasible, but technically challenging. This study aimed to determine the predictors of successful endovascular recanalization in patients with symptomatic nonacute ILAO.

METHODS

The outcomes of endovascular recanalization attempts performed in 70 consecutive patients showing symptomatic nonacute ILAO with hemodynamic cerebral ischemia between January 2016 to December 2022 were reviewed. Potential variables, including clinical and radiological characteristics related to technical success, were collected. Univariate analysis and multivariate logistic regression were performed to identify predictors of successful recanalization for nonacute ILAO.

RESULTS

Technically successful recanalization was achieved in 57 patients (81.4%). The periprocedural complication rate was 21.4% (15 of 70), and the overall 30-day morbidity and mortality rates were 7.1% (5 of 70) and 2.9% (2 of 70), respectively. Univariate analysis showed that successful recanalization was associated with occlusion duration, stump morphology, occlusion length, slow distal antegrade flow sign, and the presence of bridging collateral vessels. Multivariate analysis showed that occlusion duration ≤ 3 months (odds ratio [OR]: 22.529; 95% confidence interval [CI]: 1.636-310.141), tapered stump (OR: 7.498; 95% CI: 1.533-36.671), and occlusion length < 10 mm (OR: 7.049; 95% CI: 1.402-35.441) were independent predictive factors for technical success of recanalization.

CONCLUSIONS

Occlusion duration ≤ 3 months, tapered stump, and occlusion length < 10 mm were independent positive predictors of technical success of endovascular recanalization for symptomatic nonacute ILAO. These findings may help predict the likelihood of successful recanalization in patients with symptomatic nonacute ILAO and also provide a reference for the selection of appropriate patients. Further prospective and multicenter studies are required to validate our findings.

Intravascular Ultrasound in Chronic Total Occlusion Percutaneous Coronary Intervention: Solving Ambiguity and Improving Durability

Chronic total occlusions remain among the most technically challenging lesions to treat percutaneously. Limitations of 2-dimensional angiography may further hinder successful treatment of these lesions. Intrasvascular ultrasound has a key role in percutaneous recanalization for a chronic total occlusion by providing key lesion characteristics, facilitating guidewire crossing, elucidating the intraplaque or extralaque path of the guidewire, optimizing lesion preparation, guiding stenting and identifying suboptimal results. Live visualization of the guidewire during crossing may reduce extraplaque wire tracking. This review describes the practical uses of intravascular imaging for commonly encountered scenarios when treating chronic total occlusions.

A weighted angiographic scoring model (W-CTO score) to predict success of antegrade wire crossing in chronic total occlusion: analysis from a single centre

AIMS

The aim of this study was to derive a weighted score model predicting success/failure of antegrade wire crossing in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Four hundred and four consecutive CTO cases (408 lesions) undergoing CTO-PCI between January 2009 and March 2015 were included. Data were divided into two sets, namely "derivation" and "validation", in a 70:30 ratio. The score was derived using multivariate analysis to identify independent predictors of wire crossing failure from the derivation set (n=285 lesions) and validated on the remaining 123 lesions (validation set). The overall procedural success rate was 83.6%. Independent predictors of CTO-PCI failure and their contribution to the weighted score were a blunt stump (beta coefficient 2.12), length of occlusion >20 mm (beta coefficient 1.71), presence of calcification (beta coefficient 0.72), presence of tortuosity (beta coefficient 1.06) and collateral with Rentrop grade <2 (beta coefficient 1.06). The respective scores allotted were +2.0, +1.5, +1, +1, +1 (total 6.5), rounding the coefficient to the nearest 0.5. Score values of 0-2, >2-4 and >4 were classified as low, intermediate and high levels of difficulty for CTO-PCI success and were associated with 98%, 74.2%, and 42.5% (p<0.0001), respectively, of antegrade wire crossing success in the derivation set. This was also validated on the validation set with CTO success in the three derived difficulty levels being 100%, 82.4% and 48.4%, respectively.

CONCLUSIONS

Our weighted angiographic CTO score is a strong predictor of final antegrade wire crossing success and could be used in day-to-day clinical practice of CTO interventions.

Coronary Computed Tomography Angiography Predicts Guidewire Crossing and Success of Percutaneous Intervention for Chronic Total Occlusion

Background—

We developed a model that predicts difficulty of percutaneous coronary intervention for coronary chronic total occlusion (CTO) using coronary computed tomographic angiography.

Methods and Results—

A total of 684 CTO lesions with preprocedural computed tomographic angiography were enrolled from 4 centers. Data were randomly divided into derivation and validation datasets at 2:1 ratio. The end point was successful guidewire crossing ≤30 minutes, which was met in 50%. The KCCT (Korean Multicenter CTO CT Registry) score was developed based on independent predictors identified by multivariable analysis, which were proximal blunt entry, proximal side branch, bending, occlusion length ≥15 mm, severe calcification, whole luminal calcification, reattempt, and ≥12 months or unknown duration of occlusion. The KCCT score was compared with the other prediction scores, including angiography-based J-CTO, PROGRESS-CTO, CL-score, and CT-based CT-RECTOR. The probability of guidewire crossing ≤30 minutes declined consistently from 100% to 0% according to the KCCT score ( P <0.01, all). The KCCT score showed higher discriminative performance compared with the other scoring systems (c-statistics=0.78 versus 0.65–0.72, P <0.001, all). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of a KCCT score of <4 for guidewire crossing ≤30 minutes was 70%, 68%, 72%, 73%, and 70%, respectively. The KCCT score also showed consistent results with procedural success ( P <0.05, all). These results could be reproduced in validation data set ( P <0.05, all).

Conclusions—

KCCT scoring could predict successful guidewire crossing ≤30 minutes and also procedural success. KCCT scoring may enable noninvasive grading difficulty of CTO percutaneous coronary intervention.

Coronary Stenting or Balloon Angioplasty for Chronic Total Coronary Occlusions: The Taiwan Experience (A Single-Center Report)

The authors conducted this study to compare the restenosis and reocclusion rates of primary balloon angioplasty alone versus angioplasty followed by stenting in Taiwanese patients with chronic total occlusions. They also evaluated whether stenting reduced the incidence of restenosis and improved left ventricular function in these patients. From October 1998 to April 2000, a total of 294 patients with chronic total occlusion (Thrombolysis in Myocardial Infarction grade 0 flow) underwent recanalization using balloon angioplasty alone or followed by stent implantation. Of these, only 129 patients were included after procedural failure and patients lost to follow-up; 62 patients were placed in the stent group, while 67 patients were assigned to the percutaneous transluminal coronary angioplasty (PTCA) group. Coronary angiography was performed at baseline and at 6 months follow-up or earlier if angina or objective evidence of ischemia involving the target vessel or other vessels was present. Procedural success was 60%. Minimal lumen diameter increased significantly after stenting: 2.97 ±0.41 vs 2.24 ±0.41 (p<0.001); 60% of patients in the stent group were free of restenosis, whereas only 33% in the PTCA group were free of restenosis at follow-up. Only 1 patient in the stent group had reocclusion, as opposed to 17 (25%) patients in the PTCA group (p<0.001). The follow-up minimal lumen diameter (MLD) at 6 months was significantly larger in the stent group: 1.80 ±0.85 mm vs 1.08 ±0.82 mm (p<0.001). Left ventricular function improved in the stent group, but not in the PTCA group (58.44 ±16.58% to 63.60 ±14.59% [p<0.001] vs 54.13 ±15.66% to 54.31 ±15.60% [p=0.885]). More patients had angina in the PTCA group than in the stented group 43 vs 29 (p=0.053). The postprocedural MLD and reference vessel diameter (RVD) were the strong predictors of restenosis and follow-up MLD (p<0.001). Stenting of chronically occluded arteries significantly reduced the incidence of reocclusion and restenosis, at the same time improving left ventricular function in these patients. This should be the procedure of choice after successful angioplasty of chronically occluded vessels.

Theory and practical based approach to chronic total occlusions

Coronary chronic total occlusions (CTOs) represent the most technically challenging lesion subset that interventional cardiologists face. CTOs are identified in up to one third of patients referred for coronary angiography and remain seriously undertreated with percutaneous techniques. The complexity of these procedures and the suboptimal success rates over a long period of time, along with the perception that CTOs are lesions with limited scope for recanalization, account for the underutilization of CTO Percutaneous Coronary Intervention (PCI). During the last years, dedicated groups of experts in Japan, Europe and United States fostered the development and standardization of modern CTO recanalization techniques, achieving success rates far beyond 90%, while coping with lesions of increasing complexity. Numerous studies support the rationale of CTO revascularization following documentation of viability and ischemia in the territory distal to the CTO. Successful CTO PCI provide better tolerance in case of future acute coronary syndromes and can significantly improve angina and left ventricular function. Randomized trials are on the way to further explore the prognostic benefit of CTO revascularization. The following review reports on the theory and the most recent advances in the field of CTO recanalization, in an attempt to promote a more balanced approach in patients with chronically occluded coronary arteries.

Angiographic and clinical comparisons of intravascular ultrasound- versus angiography-guided drug-eluting stent implantation for patients with chronic total occlusion lesions: two-year results from a randomised AIR-CTO study

AIMS

This study sought to compare angiographic endpoints at one-year follow-up after a drug-eluting stent implantation guided by either intravascular ultrasound (IVUS) or angiography in patients with chronic total occlusion (CTO) lesions.

METHODS AND RESULTS

Patients with at least one CTO lesion recanalised successfully were randomly assigned to the IVUS-guided or the angiography-guided group. The use of IVUS for penetration of the true lumen and optimisation of stent expansion was only done in the IVUS-guided group. The primary endpoint was in-stent late lumen loss (LLL) at one-year follow-up. A total of 230 patients with CTO lesions after successful recanalisation were enrolled and followed with office visits or telephone contact up to 24 months. In-stent LLL in the IVUS-guided group was significantly lower compared to the angiography-guided group at one-year follow-up (0.28±0.48 mm vs. 0.46±0.68 mm, p=0.025), with a significant difference in restenosis of the "in-true-lumen" stent between the two groups (3.9% vs.13.7%, p=0.021). The minimal lumen diameter and minimal stent cross-section area significantly and negatively correlated with LLL (all p<0.001). The rates of adverse clinical events were comparable between the IVUS- and angiography-guided groups at two-year follow-up (21.7% vs. 25.2%, p=0.641).

CONCLUSIONS

The IVUS-guided stenting of the CTO lesion was associated with less LLL and a lower incidence of "in-true-lumen" stent restenosis. Additional study is required to identify the clinical benefit of the IVUS-guided procedure for CTO lesions. [ChiCTR-TRC-10000996].

Role of CT Coronary Angiography in Recanalization of Chronic Total Occlusion

Chronic total occlusion (CTO) is considered as the most challenging frontier in interventional cardiology and the last one to be conquered. With availability of state of the art hardware, wires and catheters in particular and increased skills of the operators, the success rate for recanalization of CTO by percutaneous catheter intervention (PCI) has improved. Yet the complications rate and longterm adverse events are high, mostly due to failure in tracking or navigation of hardware through the occluded CTO segment, prolonged exposure to radiation and high doses of contrast used. Therefore, proper selection of patient is of utmost importance. One of the major challenges for successful CTO recanalization is satisfactory visualization of the occluded CTO segment. Conventional invasive catheterization fails to fill the gap and the shortcomings and handicaps of such invasive imaging can be resolved with the use of non-invasive CT coronary angiography (CTCA). CTCA helps to better define the morphological features of the occluded CTO segment, which are established predictors of success, like the actual length of the occluded segment and any calcification or tortuosity in its course. Integration of reconstructed three-dimensional CT coronary images with twodimensional fluoroscopic images, offers directional guide to select the best angiographic plane for visualization of angiographically “missing segment”. With advances in CT technology, CTCA has now become an established technology for pre-procedure evaluation of CTO segment, thereby help in planning and execution of successful PCI.

Training Standards and Recommendations for Intervention on Chronic Total Occlusions

Despite major advances in coronary intervention, the recanalization of a chronic total occlusion (CTO) remains a challenge for many interventional cardiologists. Complex anatomy and lesion characteristics demand a special set of skills for procedural success.

Provided patient selection is appropriate, CTO intervention can confer a variety of benefits including relief of angina, improvement in left ventricular function and reduction in ischemic burden. The chances of procedural success are enhanced by having a dedicated CTO program. This involves adequate training of staff, quality control and availability of equipment. A diverse toolkit allows variation in strategy and increases procedural success. Further, skills and equipment are required to manage complications like vessel dissection, perforation and the resultant ischemic or mechanical complications. These procedures can often be lengthy and giving careful consideration to peri-procedural issues like radiation exposure and contrast dose plays a vital role in ensuring optimal patient outcomes and radiation hygiene.

In this article we review the evidence behind indications for CTO intervention and discuss the development of a CTO program.

Procedural failure of chronic total occlusion percutaneous coronary intervention: Insights from a multicenter US registry

BACKGROUND

The hybrid approach to chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has significantly increased procedural success rates, yet some cases still fail. We sought to evaluate the causes of failure in a contemporary CTO PCI registry.

METHODS

We examined 380 consecutive patients who underwent CTO-PCI at 4 high volume CTO PCI centers in the United States using the "hybrid" approach. Clinical, angiographic, complication, and efficiency outcomes were compared between successful and failed cases. Failed cases were individually reviewed by an independent reviewer to determine the cause of failure.

RESULTS

Procedural success was 91.3%. Compared with patients in whom CTO PCI was successful, those in whom CTO PCI failed had similar baseline clinical characteristics, but were more likely to have longer occlusion length, more tortuosity, more proximal cap ambiguity and blunt stump, and higher mean J-CTO scores (2.8 ± 1.1 vs. 3.5 ± 1.0, P < 0.001), and less likely to have collaterals suitable for the retrograde approach (66% vs. 45%, P = 0.021). Failure was due to a complication in 10 cases (30%). In the remaining 23 cases (70%) failure was due to inability to wire the lesion (n = 21, 4 of which were CTOs due to in-stent restenosis), or poor antegrade flow after PCI (n = 5).

CONCLUSIONS

Compared with successful cases, failed CTO-PCI cases are more likely to have higher J-CTO scores, longer occlusion length, ambiguous proximal cap and no appropriate collaterals for retrograde crossing. Development of novel CTO crossing techniques is needed to further increase CTO PCI success rates.

Percutaneous coronary intervention to treat chronic total occlusion: predictors of technical success and one-year clinical outcome

We investigated the overall success rate of percutaneous coronary intervention (PCI) as a treatment for coronary chronic total occlusion and sought to determine the predictive factors of technical success and of one-year major adverse cardiac events (MACE). These factors have not been conclusively defined. Using data from our single-center PCI registry, we enrolled 269 consecutive patients (mean age, 56.13 ± 10.72 yr; 66.2% men) who underwent first-time PCI for chronic total occlusion (duration, ≥3 mo) from March 2006 through September 2010. We divided them into 2 groups: procedural success and procedural failure. We compared occurrences of in-hospital sequelae and one-year MACE between the groups, using multivariate models to determine predictors of technical failure and one-year clinical outcome. Successful revascularization was achieved in 221 patients (82.2%). One-year MACE occurred in 13 patients (4.8%), with a predominance of target-vessel revascularization (3.7%). The prevalence of MACE was significantly lower in the procedural-success group (1.8% vs 18.8%; P <0.001). In the multivariate model, technical failure was the only predictor of one-year MACE. The predictors of failed procedures were lesion location, multivessel disease, the occurrence of dissection, a Thrombolysis In Myocardial Infarction flow grade of 0 before PCI, the absence of tapered-stump arterial structure, and an increase in serum creatinine level or lesion length. In our retrospective, observational study, PCI was successful in a high percentage of chronic total occlusion patients and had a low prevalence of complications. This suggests its safety and effectiveness as a therapeutic option.

Contemporary overview and clinical perspectives of chronic total occlusions

Chronic total occlusions (CTOs) are often detected on diagnostic coronary angiograms, but percutaneous coronary intervention (PCI) for CTO is currently infrequently performed owing to high technical difficulty, perceived risk of complications, and a lack of randomized data. However, successful CTO-PCI can significantly increase a patient's quality of life, improve left ventricular function, reduce the need for subsequent CABG surgery, and possibly improve long-term survival. A number of factors must be taken into account for the selection of patients for CTO-PCI, including the extent of ischaemia surrounding the occlusion, the level of myocardial viability, coronary location of the CTO, and probability of procedural success. Moreover, in patients with ST-segment elevation myocardial infarction, a CTO in a noninfarct-related artery might lead to an increase in infarct area, increased end-diastolic left ventricular pressure, and decreased left ventricular function, which are all associated with poor clinical outcomes. In this Review, we provide an overview of the anatomy and histopathology of CTOs, perceived benefits of CTO-PCI, considerations for patient selection for this procedure, and a summary of emerging techniques for CTO-PCI.

The role for adjunctive image in pre-procedural assessment and peri-procedural management in chronic total occlusion recanalisation

Non invasive coronary angiography with multislice computed tomography has exquisite sensitivity to detect calcium and even the faintest late contrast filling of the distal vessel. Calcium burden and occlusion length are still valuable markers of duration, complexity and success of the recanalisation procedure. The ability to visualise the vessel also in the occluded segment, especially if calcified, can also help the operator to understand where to pierce the proximal cap in stumpless occlusions and to predict unusual courses, especially in very tortuous arteries. Imaging side by side CT images and angiography during the recanalisation procedure is an established practice in many active CTO laboratories and algorithms for co-registration are designed to overcome the challenges of systo-diastolic and respiratory motion. Intravascular ultrasound is used in almost all cases by the experienced Japanese CTO operators but most of the times its main use is a better identification of the diseased segment after predilatation to ensure complete stent cover and appropriate stent expansion, an application similar to other complex non occlusive lesions. The specificity of IVUS during CTO recanalisation is the identification of the vessel path in stumpless occlusions and the guidance of wire reentry especially during reverse Controlled Retrograde Anterograde Tracking. Optical coherence tomography has limitations in the setting of CTO recanalisation because of the need of forceful contrast flushing to clear blood, contraindicated in the presence of anterograde dissections, and the limited penetration. The variability in the use of both non-invasive and invasive imaging during CTO recanalisation is immense, going from more than 90% in Japan to less than 20% in Europe and intermediate penetration in the USA. Probably the explanation is almost only in availability and cost because all countries see a progressive increase of use suggesting that these methods are becoming an established tool for guidance of CTO recanalisation.

Wire Strategy as a First Option: Properties of the Tools

This article discusses interventional guidewires in general and how they are best used in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in particular. The components that make a guidewire and the various design options are described. The specific characteristics of these options and how they relate to various aspects of PCI are discussed. Guidewire design as it applies specifically to the tasks particular to CTO PCI is discussed.

Chronic total occlusions: successful recanalization of very old lesions

PURPOSE

The treatment of chronic total occlusion is thought to be the final frontier in treating coronary artery disease nonsurgically. In the past, an old occlusion was not likely to be treated successfully percutaneous. We have had success in revascularizing some very old 20 plus year old occlusions percutaneously.

METHODS

Six patients were treated who had >20-year-old occlusions. Five patients were male; mean age of patients was 72.2 years (range 63-86). Mean age of the occlusion was 24.8 years. All patients had ischemia in the corresponding territory. Four of the patients had right coronary artery occlusions; one had a left circumflex occlusion and one had left anterior descending artery occlusion.

RESULTS

Using a combination of radial and/or femoral approach, we successfully recanalized all of these old occlusions. No patients had major adverse cardiac events. Two patients developed restenosis at follow-up that was subsequently treated uneventfully. All the patients had a complete relief of angina.

CONCLUSION

In a small single center experience, even very old occlusions >20-year old can be effectively treated with dedicated systems, excellent guiding catheter support and experienced physicians.

Recanalization of isolated chronic total occlusions in patients with stable angina

BACKGROUND

Despite procedural advances, recanalization of chronic total occlusions (CTOs) with percutaneous coronary intervention (PCI) remains controversial, particularly given that its long-term benefits are unclear. We assessed the association between successful PCI and symptom improvement as well as outcomes in patients with CTO and stable angina.

METHODS

We performed a retrospective study of 386 consecutive patients undergoing attempted PCI of an isolated CTO (i.e., no other angiographically-significant disease was present). We analyzed prospectively the change in Canadian Cardiovascular Society (CCS) classification system and occurrence of major adverse cardiovascular events (death, myocardial infarction or target vessel revascularization), after stratifying patients by procedural success. To understand which patients might benefit most from attempted PCI, multivariable models were constructed to predict: likelihood of successful PCI and symptom improvement, defined as resolution of angina or improvement of ≥ 2 CCS classes.

RESULTS

A total of 247 (64%) patients had successful PCI. Greater symptom improvement was noted after successful PCI at both 6 months (79.8% versus 34.5% with resolution of angina or improvement of ≥ 2 CCS classes, p<0.01) and 24 months (71.7% and 20.9%, respectively, p<0.01). No differences were noted in MACE (11.3% vs. 10.0% at 6 months, p=0.70; and 18.6% vs. 19.4% at 24 months, p=0.84). Multivariable analysis identified several factors associated with successful PCI, but not predictive of symptom improvement. In conclusion, successful PCI of an isolated CTO improves symptom burden, but is not associated with MACE at 6 or 24 months.

CONCLUSIONS

Several factors are associated with successful PCI, but identifying those most likely to have symptom improvement remains challenging.

Predicting successful guidewire crossing through chronic total occlusion of native coronary lesions within 30 minutes: the J-CTO (Multicenter CTO Registry in Japan) score as a difficulty grading and time assessment tool

OBJECTIVES

This study sought to establish a model for grading lesion difficulty in interventional chronic total occlusion (CTO) treatment.

BACKGROUND

Owing to uncertainty of success of the procedure and difficulties in selecting suitable cases for treatment, performance of interventional CTO remains infrequent.

METHODS

Data from 494 native CTO lesions were analyzed. To eliminate operator bias, the objective parameter of successful guidewire crossing within 30 min was set as an end point, instead of actual procedural success. All observations were randomly assigned to a derivation set and a validation set at a 2:1 ratio. The J-CTO (Multicenter CTO Registry of Japan) score was determined by assigning 1 point for each independent predictor of this end point and summing all points accrued. This value was then used to develop a model stratifying all lesions into 4 difficulty groups: easy (J-CTO score of 0), intermediate (score of 1), difficult (score of 2), and very difficult (score of ≥ 3).

RESULTS

The set end point was achieved in 48.2% of lesions. Independent predictors included calcification, bending, blunt stump, occlusion length >20 mm, and previously failed lesion. Easy, intermediate, difficult, and very difficult groups, stratified by J-CTO score, demonstrated stepwise, proportioned, and highly reproducible differences in probability of successful guidewire crossing within 30 min (87.7%, 67.1%, 42.4%, and 10.0% in the derivation set and 92.3%, 58.3%, 34.8%, and 22.2% in the validation set, respectively). Areas under receiver-operator characteristic curves were comparable (derivation: 0.82 vs. validation: 0.76).

CONCLUSIONS

This model predicted the probability of successful guidewire crossing within 30 min very well and can be applied for difficulty grading.

The role of coronary CT angiography in chronic total occlusion intervention

Revascularisation by percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) is often a technically challenging procedure. The manipulation of wires and devices through a CTO during PCI without any means to visually identify vessel-wall boundaries involves an inherent risk of complications such as arterial dissection, perforation and cardiac tamponade. With the tremendous advances in multidetector CT technology and the popularity of utilising coronary CT angiogram (CCTA) for a workup of chest pain patients, an increasing number of CTO cases are being encountered. Therefore, the primary goal of CCTA for imaging in CTOs involves identifying the presence and locations of CTO as well as predicting the potential clinical benefits derived from revascularisation of the occluded segment. The secondary goal includes preprocedural planning to shorten procedure times, visualisation of the procedure in predicting the ease with which a CTO can be crossed and the frequency of procedure-related complications such as contrast nephropathy and radiation skin injury. Apart from these, CCTA also plays a role in postprocedural assessment of the revascularised arterial segments and long-term follow-up on the patency of coronary stents.

Real-time 3D imaging in the cardiac catheterization laboratory

Worldwide experience in coronary catheterization and angiography for the detection and evaluation of lumen narrowing is extensive. Conventional coronary angiography analysis is complex since these arteries are of relatively small caliber and in constant movement, while being synchronized with the movement of the heart chambers and respiratory system. Moreover, atherosclerotic plaques in the coronary tree are themselves very intricate and frequently positioned in eccentric locations. The last decade has witnessed significant advances as novel data acquisition and processing techniques have been introduced. Researchers have developed novel processing systems that make it possible to construct 3D images in real-time during coronary intervention. The most common solutions are rotational imaging and reconstruction from multiple single-plane images. These techniques produce real-time 3D images of the coronary arteries in the catheterization laboratory. This article describes these state-of-the-art imaging methods and other specific novel applications in clinical practice, such as stent enhancement, guidance during transcatheter aortic valve implantation and advanced geometrical analysis with computational fluid dynamics.

Percutaneous recanalization of coronary chronic total occlusions: current devices and specialized wire crossing techniques

Treatment of coronary chronic total occlusions (CTOs) remains a challenging obstacle, posing a considerable barrier to achieving successful complete revascularization. By nature of their complexity, percutaneous CTO interventions are associated with lower rates of procedural success, higher complication rates, greater radiation exposure and longer procedure times compared with non-CTO interventions. In the last few years, development in guidewires, devices and the emergence of new techniques from Japanese centers resulted in higher success rates in the hands of experienced operators. The impact of drug eluting stents on restenosis has improved long-term outcomes after successful recanalization. Successful revascularization is associated with improved long-term survival, reduced symptoms, improved left ventricular function and reduced need for coronary bypass surgery. This paper reviews the current devices and specialized crossing techniques of percutaneous intervention to relieve CTOs.

The efficacy of a bilateral approach for treating lesions with chronic total occlusions the CART (controlled antegrade and retrograde subintimal tracking) registry

OBJECTIVES

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.

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Trends in outcomes after percutaneous coronary intervention for chronic total occlusions: a 25-year experience from the Mayo Clinic

OBJECTIVES

The aim of our study was to examine the trends in procedural success, in-hospital, and long-term outcomes after percutaneous coronary intervention (PCI) for chronic total occlusions (CTO) over the last 25 years from a single PCI registry and to examine the impact of drug-eluting stents.

BACKGROUND

The percutaneous treatment of CTO remains a major challenge. Past studies have used variable definitions of CTO, and there are limited data available from contemporary practice.

METHODS

We evaluated the outcomes of 1,262 patients from the Mayo Clinic registry who required PCI for a CTO. The patients were divided into 4 groups according to the time of their intervention: group 1 (percutaneous transluminal coronary angioplasty era), group 2 (early stent era), group 3 (bare-metal stent era), and group 4 (drug-eluting stent era).

RESULTS

Procedural success rates were 51%, 72%, 73%, and 70% (p < 0.001), respectively, in the 4 groups. In-hospital mortality (2%, 1%, 0.4%, and 0%, p = 0.009), emergency coronary artery bypass grafting (15%, 3%, 2%, and 0.7%, p < 0.001), and rates of major adverse cardiac events (8%, 5%, 3%, and 4%, p = 0.052) decreased over time. During follow-up, the combined end point of death, myocardial infarction, or target lesion revascularization, was significantly lower in the 2 most recent cohorts compared with those patients treated before (p = 0.001 for trend). Technical failure to treat the CTO was not an independent predictor of long-term mortality (hazard ratio 1.16 [95% confidence interval 0.90 to 1.5], p = 0.25).

CONCLUSIONS

Procedural success rates for CTO have not improved over time in the stent era, highlighting the need to develop new techniques and devices. Compared with the prestent era, in-hospital major adverse cardiac events and 1-year target vessel revascularization rates have declined by approximately 50%.

A new understanding of chronic total occlusion from a novel PCI technique that involves a retrograde approach to the right coronary artery via a septal branch and passing of the guidewire to a guiding catheter on the other side of the lesion

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) by the antegrade approach is sometimes difficult, especially in the right coronary artery (RCA). We performed successful PCls following a retrograde approach via a septal branch in 2 patients with CTO in RCA. The method involves leading the retrograde guidewire outside the body through an opposite guiding catheter after the wire crosses the target lesion. A balloon or stent could then be delivered retrogradely or antegradely. Even a soft retrograde wire always crosses the lesion through the true lumen, as confirmed by IVUS. Selecting a suitable collateral, a straighter rather than a larger one, is crucial. Our results do not support the current concept regarding CTOs. Probably, the distal fibrous cap is soft and the proximal one has a thin point that soft wires, even blunt ones, can penetrate easily. The distal penetration point appears to connect to the proximal uncalcified thin point. Many channels seem to spread out from the proximal side, tree-like, within the lesion. In the retrograde approach, the wire is unlikely to enter these branch channels. The results suggest that PCI by the retrograde approach may be effective for treating CTOs of RCA.

The feasibility of percutaneous transradial coronary intervention for chronic total occlusion

We evaluated the feasibility of the transradial coronary intervention (TRCI) in 85 consecutive patients with chronic total occlusion (CTO). Clinical, angiographic and procedural factors were compared between the success and failure groups. An overall success rate of 65.5% (57 of 87 lesions) was achieved with TRCI, and the most common cause of failure was an inability to pass the lesion with a guidewire. A multivariate analysis demonstrated that the most significant predictor of failure was the duration of occlusion (OR 1.064 per month, 95% CI 1.005 to 1.126, p = 0.03). The procedural success rate improved with use of new-generation hydrophilic guidewires. The 6 Fr guiding catheters were used in the majority of the 70 cases (81%). Five cases were crossed over to a femoral artery approach due to engagement failure of the guiding catheter into the coronary ostium because of severe subclavian tortuosity and stenosis in two cases, radial artery looping in one case, and poor guiding support in two cases. There were no major entry site complications. In conclusion, the radial artery might be a feasible vascular route in coronary interventions for CTO, with comparable procedural success and no access site complications.

Guidewire navigation in coronary artery stenoses using a novel magnetic navigation system: first clinical experience

The objective of this study was to investigate the efficacy of guidewire navigation across coronary artery stenoses using magnetic navigation system (MNS) versus conventional navigation. The MNS is a novel option to facilitate access to target lesions, particularly in tortuous vessels. In an experimental study using a challenging vessel phantom, magnetic-navigated guidewire passage has been reported to reduce fluoroscopy and procedure time significantly. Both magnetic and manual guidewire navigation were attempted in 21 consecutive diseased coronary arteries. The study endpoint was defined as an intraluminal wire position distal to the stenosis. Procedural success was defined as successful guidewire passage without procedural events. Procedure time, amount of contrast, fluoroscopy time, and radiation dose/area product (DAP) were evaluated. There were no procedural events related to either guidewire. Although the lesions attempted had relatively simple and straightforward characteristics, significantly shorter procedure and fluoroscopy time were observed for manual guidewire navigation compared to MNS (median, 40 vs. 120 sec, P=0.001; 38 vs. 105 sec, P=0.001, respectively). Contrast amount and DAP were higher in MNS than in conventional method (median, 13 vs. 9 ml, P=0.018; 215 vs. 73 Gym2, P=0.002, respectively). The magnetic wire did not cross in two vessels. Guidewire navigation using MNS presented a novel, safe, and feasible approach to address coronary artery lesions. Clinical studies are needed to evaluate the potential benefit of the MNS in more complex coronary lesions and tortuous anatomy.

A novel approach to chronic total occlusions: the crosser system

OBJECTIVES

To evaluate safety and efficacy of the CROSSER CTO Recanalization System (CROSSER).

BACKGROUND

The CROSSER, a novel device dedicated to recanalization of chronic total occlusions (CTO), relies on a monorail catheter delivering vibrational energy to facilitate the crossing of occluded coronary arteries.

METHODS

We included de novo or restenotic occlusions in native coronary arteries with typically unfavorable characteristics and a prior failed guidewire attempt either performed in a previous procedure or just before the usage of the CROSSER. The end points analyzed were technical success (ability to cross or facilitate a guidewire crossing into the true lumen), angiographic success (<20% residual stenosis and TIMI flow grade 3), and clinical success (angiographic success and freedom from major adverse cardiac events at 30 days).

RESULTS

Twenty-eight patients (30 lesions) were included. The morphology was blunt in 83.3% and the length of the occlusion was >20 mm in 76.6%. The median age of the CTO was 9 months (range 3-60 months). Technical success was obtained in 19 (63%) occlusions and angiographic success in 16 (53%): 26.3% in lesions with prior procedural failure and 73.7% when CROSSER was attempted after initial guidewire failure. Complications were: one guidewire perforation without consequences and one peri-procedural myocardial infarction (MI). No events occurred within 30-day follow-up after discharge.

CONCLUSIONS

In our experience, the CROSSER System is safe and increases the success of opening CTO refractory to guidewires. This novel device may represent an useful adjunct to the armamentarium of the interventional cardiologist.

Novel double catheter technique in complex percutaneous coronary interventions

We present a novel double catheter technique for successful complex intervention of a very old proximal left circumflex chronic total occlusion (>10 years old). Prior attempts of guide wire passage using bare wire alone, over-the wire balloon or microcatheter support techniques were unsuccessful.

Effect of percutaneous coronary intervention of nonacute total coronary artery occlusions on QT dispersion

BACKGROUND

Myocardial ischemia is one of several potential causes of increased QT dispersion (QTd) in patients with nonacute total coronary artery occlusions (TCOs). We sought to assess the effect of percutaneous revascularization (PCI) of TCO on QTd and the relationship between QTd and long-term vessel patency.

METHODS

Seventy patients enrolled in the TOSCA were analyzed. Patients were undergoing PCI of a TCO > 72 hours' duration. Two independent reviewers measured QTd from electrocardiograms done immediately before PCI (PRE), 12 to 18 hours after PCI (POST), and then at 6 months (6M). Follow-up angiography was performed at 6 months.

RESULTS

Mean QTd decreased from PRE (77 +/- 29 milliseconds) to POST (66 +/- 26 milliseconds, P < .001) and 6M (65 +/- 25 milliseconds, P < .001). Patients with the same or longer QTd at 6 months compared with POST (POST < or = 6M) had significantly higher risk of failed target-vessel patency (odds ratio 10.3, 95% CI 1.24-84.8) than patients with QTd reduction at 6M versus POST values.

CONCLUSION

Revascularization of TCO resulted in a decrease in QTd, which was sustained at 6M. This suggests that PCI to a TCO has a beneficial effect on stabilization of the underlying ischemic substrate. Furthermore, absence of QTd reduction at 6M versus POST was associated with increased risk of failed target-vessel patency.

Percutaneous coronary intervention: recommendations for good practice and training

Cardiologists undertaking percutaneous coronary intervention (PCI) are excited by the combination of patient and physician satisfaction and technological advance occurring on the background of the necessary manual dexterity. Progress and applicability of percutaneous techniques since their inception in 1977 have been remarkable; a sound evidence base coupled with the enthusiasm and ingenuity of the medical device industry has resulted in a sea change in the treatment of coronary heart disease (CHD), which continues to evolve at breakneck speed. This is the third set of guidelines produced by the British Cardiovascular Intervention Society and the British Cardiac Society. Following the last set of guidelines published in 2000, we have seen PCI activity in the UK increase from 33,652 to 62,780 (87% in four years) such that the PCI to coronary artery bypass grafting ratio has increased to 2.5:1. The impact of drug eluting stents has been profound, and the Department of Health is investigating the feasibility of primary PCI for acute myocardial infarction. Nevertheless, the changes in the structure of National Health Service funding are likely to focus our attention on cost effective treatments and will require physician engagement and sensitive handling if we are to continue the rapid and appropriate growth in our chosen field. It is important with this burgeoning development now occurring on a broad front (in both regional centres and district general hospitals) that we maintain our vigilance on audit and outcome measures so that standards are maintained for both operators and institutions alike. This set of guidelines includes new sections on training, informed consent, and a core evidence base, which we hope you will find useful and informative.

Intracoronary Fibrin-Specific Thrombolytic Infusion Facilitates Percutaneous Recanalization of Chronic Total Occlusion

OBJECTIVES

We sought to investigate the benefit, predictors of procedural success, and safety of pre-procedural intra-coronary fibrin-specific lytic infusion (ICL) in patients with failed prior percutaneous coronary intervention (PCI) for chronic total occlusions (CTO).

BACKGROUND

Percutaneous coronary intervention for CTO remains a challenge with a high incidence of procedural failure secondary to inability to cross the occlusion with the guidewire.

METHODS

Eighty-five patients who underwent unsuccessful PCI procedures of CTO (more than three months' duration) had a repeat attempt of recanalization with the use of pre-procedural ICL. Patients received a weight-adjusted dose of either alteplase (tPA) (2 to 5 mg/h) or tenecteplase (TNK) (0.5 mg/h) for a total of 8 h. The total dose of ICL therapy was infused split between the guiding catheter and an intracoronary infusion catheter. A step-down multivariate logistic regression analysis was completed to determine the best predictors of procedural success. In-hospital major adverse cardiac events (MACE) including myocardial infarction, acute reocclusion, stroke, and death, as well as bleeding complications, were also examined.

RESULTS

The procedure was successful in 46 of 85 cases (54%). Four of 85 (5%) contained dissections that did not result in perforations, tamponade, or MACE. The incidence of groin complications was 7 of 85 (8%) and of bleeding complications requiring transfusions was 3 of 85 (3.5%). On multivariate analysis, predictors of success were tapering morphology (odds ratio, 15.5; 95% confidence interval, 3.73 to 63; p = 0.0002) and lack of bridging collaterals (odds ratio, 5.08; 95% confidence interval, 1.53 to 17; p = 0.008).

CONCLUSIONS

Intracoronary infusion of fibrin-specific thrombolytic therapy may provide a valuable and safe option for facilitating percutaneous revascularization of CTO.

Success, safety, and mechanisms of failure of percutaneous coronary intervention for occlusive non-drug-eluting in-stent restenosis versus native artery total occlusion

We compared the procedural success, mechanism of failure, and safety of percutaneous coronary intervention in 235 procedures for de novo chronic total occlusions with 78 procedures for chronic occlusive in-stent restenosis. Despite similar rates of procedural success and safety profile, angiographic predictors of successful percutaneous coronary intervention for de novo chronic total occlusions played a limited role in patients who had chronic occlusive in-stent restenosis, and the mechanisms of failure were different.

Novel Approaches for the Treatment of Chronic Total Coronary Occlusions

Despite major advancements in the technology used for the percutaneous treatment of coronary artery disease, chronic total occlusions (CTOs) persist as a major challenge to the interventional cardiologist with relatively low success rates. CTOs are evident in 20% of patients undergoing cardiac catheterization and are responsible for the majority of cases that are referred to bypass surgery. There is growing evidence that patients may benefit from recanalization of a CTO by alleviation of angina, improving left ventricular function, and potentially long-term survival. The major obstacle to percutaneous recanalization of CTOs is the inability to cross the occlusion with coronary guidewires. Even when crossed, the operator has to deal with the exact location of the distal wire (e.g., dissection or true lumen) and the existence of relatively long lesion requiring multiple stents with high restenosis rates. New technologies for CTO revascularization have been focused mainly on a mechanical approach including specialized guidewires and more recently, specific devices using highly sophisticated technology such as laser guidewire, optical coherence reflectometry, and a blunt microdissection catheter. An alternate biological approach involves the local administration of enzymes such as plasminogen activators (urokinase) or collagenase, which can act locally to specifically degrade the collagen content of the CTO, thereby "softening" the occlusion and allowing easier guidewire crossing. In conclusion, CTOs emerge as a great technical challenge and are the focus of novel series of mechanical and biological approaches.

Angioplasty for chronic total occlusion by using tapered-tip guidewires

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is still technically challenging. The use of tapered-tip guidewires in these lesions may improve the success rate of PCI. In order to avoid the needless radiation exposure or contrast consumption, we have to determine a guideline for the termination of procedures in these lesions. We retrospectively analyzed the data of 182 patients between April 1997 and December 1999 (phase 1) and 80 patients between January and August 2001 (phase 2) who underwent angioplasty for CTO lesions >/= 3 months. There were no significant differences in clinical or lesion characteristics except the use of tapered-tip guidewires. Tapered-tip guidewires were used in 60% of patients in phase 2 period but no patients in phase 1 period. The overall success rate of PCI was improved from 67% in phase 1 to 81% in phase 2 (P = 0.019). In the phase 2 period, the success rate was higher in tapered-type occlusion (P = 0.002) and shorter length of occlusion (P = 0.004). Total procedure time was 46 +/- 17 min and total volume of contrast dye was 180 +/- 63 ml. The success rate was higher in patients treated by transradial coronary intervention (TRI) than transfemoral coronary intervention (89% vs. 64%; P = 0.008). The use of tapered-tip guidewires can improve the success rate of PCI in CTO lesions. The following guideline for the termination of the procedures is reasonable: time from arterial access to successful penetration of a guidewire through occlusion </= 30 min; total procedure time </= 90 min; and total dye volume </= 300 ml. TRI can achieve a high success rate even in CTO lesions provided that the case selection is adequate.

Immediate results and one-year clinical outcome after percutaneous coronary interventions in chronic total occlusions: data from a multicenter, prospective, observational study (TOAST-GISE)

OBJECTIVES

We sought to investigate the success rate and the acute and 12-month clinical outcome of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) in the contemporary era.

BACKGROUND

The technique of PCI involving CTO has improved over time. However, limited data on acute and follow-up results in patients treated with PCI on CTO in recent years are available.

METHODS

Four hundred nineteen consecutive patients scheduled for PCI of CTO of > or =30 days of duration were enrolled in 29 centers; 390 CTOs were confirmed in 376 patients in an independent core laboratory. The end points were technical and procedural success, in-hospital and 12-month major adverse cardiac events (MACE) occurrence, and 12-month symptomatic status.

RESULTS

Technical and procedural success was obtained in 77.2% and 73.3% of lesions, respectively. In-hospital major adverse cardiac events occurred in 5.1% of patients. Multivariate analysis identified CTO length >15 mm or not measurable, moderate to severe calcifications, duration > or =180 days, and multivessel disease as significant predictors of PCI failure. At 12 months, patients with a successful procedure experienced a lower incidence of cardiac deaths or myocardial infarction (1.05% vs. 7.23%, p = 0.005), a reduced need for coronary artery bypass surgery (2.45% vs. 15.7%, p < 0.0001), and were more frequently free of angina (88.7% vs. 75.0%, p = 0.008) compared with patients who had an unsuccessful procedure.

CONCLUSIONS

Successful PCI was achieved in a high percentage of CTOs with a low incidence of complications. At one-year follow-up, patients with successful PCI of a CTO had a significantly better clinical outcome than those whose PCI was unsuccessful.