Use of drug-eluting stents for chronic total occlusions: A systematic review and meta-analysis

Contemporary Approach to Chronic Total Occlusion Interventions

PURPOSE OF REVIEW

Chronic total occlusion (CTO) poses one of the greatest technical challenges to interventional cardiologists. Despite recent advancements in techniques and clinical trials showing significant benefits of CTO percutaneous coronary interventions (PCI), the proportion of patients with untreated CTOs remains high. We therefore aim to perform a comprehensive review of the various techniques available, recent advancements, benefits, and complications associated with CTO PCI.

RECENT FINDINGS

Three randomized clinical trials examining the benefits of CTO PCI have recently been presented. Scoring systems have been developed to facilitate pre-procedural estimation of success and complications of CTO PCI. Technological enhancements in coronary wires and other interventional equipment along with dedicated training for CTO operators have improved the likelihood of successful recanalization of CTOs. CTO PCI has been shown to improve patient symptoms and quality of life. It is therefore important to have an in-depth knowledge of the various CTO techniques, appropriate equipment, and complications when performing these complex procedures. Clinicians should weigh the risks and benefits and choose the appropriate patient population who may benefit from revascularization.

Percutaneous Coronary Intervention in Chronic Total Occlusion

Percutaneous coronary intervention in chronic total occlusion is a rapidly evolving area, being considered the last frontier of interventional cardiology. In recent years, the development of new techniques and equipment, as well as the training of specialized personnel, increased their success rates, making it the most predictable procedure available. Although the number of randomized and controlled studies is still limited, results from large multicentered registries allow us to safely offer this intervention to patients, as another treatment option along with the optimized drug treatment and myocardial revascularization surgery. This review summarizes the last and most relevant publications in the subject in order to provide an overall view of the field’s current status.

Percutaneous coronary interventions of chronic total -occlusions; a review of clinical indications, treatment strategy and current practice

Chronic total occlusions (CTOs) are commonly encountered in patients undergoing coronary angiography, but percutaneous coronary intervention (PCI) for CTO is currently infrequently performed owing to the perception of limited clinical benefit, high complexity and cost of intervention, and perceived risk of complications. Numerous observational studies have demonstrated that successful CTO revascularization is associated with better cardiovascular outcomes and enhanced quality of life (QOL). However, in the absence of randomized trials, its prognostic benefit remains debated. Nevertheless, over the past decade the interest in CTO-PCI has exponentially grown due to important developments in dedicated equipment and techniques, resulting in high success and low complication rates. A number of factors must be taken into consideration in selecting patients for CTO-PCI, including presence of symptoms attributable to the CTO, extent of ischaemia distal to the occlusion, and degree of myocardial viability. In this review, we focus on the impact of CTO revascularization on clinical outcomes and QOL and on appropriate patient selection. Data regarding efficacy and safety of recent advances in PCI-CTO techniques will be discussed. Steps involved in setting up a dedicated CTO program will be outlined and the current CTO landscape in Belgium will be briefly highlighted. The overall aim of this review is to promote a more balanced approach to management of patients with a CTO.

Coronary intervention for chronic total occlusion: current indications and future directions

Chronic total occlusions (CTOs) are routinely encountered during coronary angiography, but subsequent revascularization rates are low. This has likely been driven by a historical belief that there is minimal clinical benefit and poor success rates with a percutaneous coronary intervention (PCI). However, in the current era, with the development of new techniques and tools, experienced operators can perform CTO-PCI successfully in the majority of patients. The current indications and benefit of CTO-PCI remain a topic of controversy and debate. There is a growing body of predominantly nonrandomized studies reporting both short-term and long-term outcomes of CTO-PCI. Recent and upcoming randomized-controlled trials in this area will also potentially expand indications in both stable and patients with acute coronary syndrome. In this review, we will discuss the current evidence for CTO-PCI and also future directions in this field.

[Chronic coronary occlusions : When and how should revascularization be performed?]

Chronic occlusion of coronary arteries also known as chronic total occlusions (CTO) are found in approximately 20 % of patients undergoing percutaneous coronary interventions (PCI) and in approximately 50 % of patients after coronary artery bypass grafts (CABG). As a result of technical advancements in retrograde recanalization techniques specialized centers can now achieve success rates of over 85 %, regardless of the CTO anatomy. Given the complexity of retrograde CTO techniques, a consensus paper issued by the Euro CTO Club requires interventional cardiologists to have sufficient experience in antegrade approaches (>300 antegrade CTO cases and >50 per year) with an additional training program (25 retrograde cases each as first and second operating surgeon) before becoming a qualified independent retrograde surgeon. The increased investment in time and technical resources can only be justified if the patient has a clear clinical benefit. This technical advancement and the progressively clearer evidence that complete revascularization can be achieved in patients with multivessel coronary artery disease have attracted growing interest in recent years from interventional cardiologists in the recanalization of CTO.

Interventricular Septal Hematoma and Coronary-Ventricular Fistula: A Complication of Retrograde Chronic Total Occlusion Intervention

Interventricular septal hematoma is a rare complication of retrograde chronic total occlusion (CTO) percutaneous coronary interventions (PCI) with a typically benign course. Here we report two cases of interventricular septal hematoma and coronary-cameral fistula development after right coronary artery (RCA) CTO-PCI using a retrograde approach. Both were complicated by development of ST-segment elevation and chest pain. One case was managed actively and the other conservatively, both with a favorable outcome.

Update on Coronary Chronic Total Occlusion Percutaneous Coronary Intervention

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has significantly evolved during recent years. High success rates are being achieved by experienced centers and operators, but not at less-experienced centers. Use of CTO crossing algorithms can help improve the success and efficiency of these potentially lengthy procedures. There is a paucity of clinical trial data examining clinical outcomes of CTO PCI, which is critical for further adoption and refinement of the procedure. We provide a detailed overview of the clinical evidence and current available crossing strategies, with emphasis on recent developments and techniques.

Chronic total occlusions - Current techniques and future directions

Chronic total occlusions (CTOs) of coronary arteries represent a common and significant challenge to interventional cardiology. Medical therapy is often regarded as an adequate long term strategy in the management of these lesions with surgical intervention for refractory symptoms. Extensive collateralisation is used as a marker of distal coronary perfusion, further reinforcing non-invasive strategies. This together with relatively low percutaneous success rates outside of specialised centres has meant that rates of percutaneous intervention have remained low. Increasing evidence suggests that CTOs are not a benign entity. Further, symptom control and quality of life improve significantly with successful percutaneous revascularisation. Both factors have reignited interest in percutaneous modalities. The Japanese have been pioneers in the field of CTO intervention although their success rates have been difficult to replicate. New techniques and equipment developed in North America offer an alternative to the Japanese approach. These techniques focus on time, radiation and contrast minimisation. This review will assess the histopathology of CTO and shifting paradigms in CTO treatment strategies.

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Chronic total occlusions are common and prognostically important.

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Strategies for chronic occlusions are pioneered by Japanese, adapted by North American operators.

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Japanese and North American strategies appear divergent, both add considerable expertise.

Percutaneous Treatment of Coronary Chronic Total Occlusions Part 1: Rationale and Outcomes

Coronary chronic total occlusions (CTOs) are commonly encountered in patients with coronary artery disease. Compared to patients without coronary CTOs, those with CTO have worse clinical outcomes and lower likelihood of complete coronary revascularisation. Successful CTO percutaneous coronary intervention (PCI) can significantly improve angina and improve left ventricular function. Although currently unproven, successful CTO PCI might also reduce the risk for arrhythmic events in patients with ischaemic cardiomyopathy, provide better tolerance of future acute coronary syndrome, and possibly improve survival. Evaluation by a heart team comprised of both interventional and non-interventional cardiologists and cardiac surgeons is important for determining the optimal revascularisation strategy in patients with coronary artery disease and CTOs. Ad hoc CTO PCI is generally not recommended, so as to allow sufficient time for (a) discussion with the patient about the indications, goals, risks, and alternatives to PCI; (b) careful procedural planning; and (c) contrast and radiation exposure minimisation. Use of drug-eluting stents is recommended for CTO PCI, given the lower rates of angiographic restenosis compared to bare metal stents.

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.

Advances in the management of coronary chronic total occlusions

Chronic total occlusions (CTOs) have been called "the last frontier" of percutaneous coronary intervention (PCI) due to traditionally low success rates and high risk for restenosis and re-occlusion. Recent advances in equipment and crossing techniques have significantly increased CTO PCI success rates while maintaining low risk of complications. Specifically, the retrograde approach and controlled antegrade dissection and re-entry in conjunction with advanced guidewires and microcatheters have significantly improved procedural success rates. Moreover, the introduction of the "hybrid" approach has created a unified framework for operators to approach CTOs in a systematic and efficient fashion. Finally, drug-eluting stents, especially second generation, have improved long-term patency after CTO PCI.

Percutaneous Treatment of Coronary Chronic Total Occlusion Part 2: Technical Approach

Dual injection is recommended for nearly all chronic total occlusion (CTO) percutaneous coronary intervention (PCI) to determine the optimal crossing strategy and guide wire advancement into the distal true lumen. Strategies that provide enhanced guide catheter support (such as long sheaths, large-bore guiding catheters, use of guide catheter extensions, and anchor techniques) are important for maximising the success rate and efficiency of CTO PCI. Use of a microcatheter or over-the-wire balloon is strongly recommended in CTO PCI for enhancing the penetrating power of the guidewire, enabling change in tip shape and allowing guidewire change (stiff CTO guidewires are not optimal for crossing non-occluded coronary segments). Adherence to a procedural strategy that standardises CTO technique and facilitates procedural success is recommended. Such a strategy would permit stepwise decision-making for antegrade and retrograde methods; inform guidewire selection; and incorporate alternative approaches for instances of initial failure. Given the paucity of long-term outcomes with use of novel crossing techniques (antegrade dissection/re-entry and retrograde), antegrade wire escalation is the preferred CTO crossing technique, if technically feasible. Using measures to minimise radiation exposure (including but not limited to use of 7.5 frames per second fluoroscopy and use of low magnification) and contrast administration is recommended. CTO PCI is best performed at centres with dedicated CTO PCI experience and expertise. Use of crossing difficulty prediction tools, such as the J-CTO score, can facilitate the selection of cases with a high likelihood of quick crossing that can be attempted at less experienced centres.

Effects of percutaneous revascularization of chronic total occlusions on clinical outcomes: a meta-analysis comparing successful versus failed percutaneous intervention for chronic total occlusion

BACKGROUND

Chronic total occlusions (CTOs) represent the most complex and challenging coronary lesions for percutaneous coronary intervention (PCI). PCI for a CTO is a high-risk procedure and the long-term benefits of a successful percutaneous CTO recanalization over the medical management (as a result of failed PCI) are not clear, as the studies have shown conflicting results in the past. The goal of this analysis was to clarify this issue by performing a meta-analysis of the available literature.

METHODS

Using major electronic databases, we searched for studies (randomized or observational) comparing death, major adverse cardiovascular events (MACE), myocardial infarction (MI), and target vessel revascularization (TVR) between patients who underwent PCI recanalization of CTOs versus those treated with medical management as a result of failed PCI attempts.

RESULTS

We identified 23 observational studies comparing the desired clinical parameters between patients with successful CTO recanalization and those managed conservatively as a result of attempted but failed PCI. The total number of patients observed in all of the studies was 12,970 and the mean time of follow up was 3.7 ± 2.1 years. Our results indicated that successful recanalization of a CTO results in improved all-cause mortality (relative risk [RR] of 0.54, 95% confidence interval [CI] (0.45-0.65), P-value < 0.001), lower rates of MACE (RR of 0.70, 95% CI 0.60-0.83, P-value < 0.001) and reduced needs for subsequent bypass surgery (RR of 0.25, 95% CI (0.21-0.30), P-value < 0.001). The difference in long-term mortality remained statistically significant even after the adjustment for procedure related complications and in-hospital deaths.

CONCLUSION

As compared to conservative management (as a result of failed intervention), successful PCI recanalization of a CTO appears to be associated with improved long-term clinical outcomes; however, randomized controlled trials (RCTs) are needed to further confirm these results.

Meta-analysis of effect on mortality of percutaneous recanalization of coronary chronic total occlusions using a stent-based strategy

We performed a systematic review and meta-analysis comparing the all-cause mortality outcomes of successful percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) with unsuccessful CTO-PCI, using a stent-based strategy. Multiple studies comparing successful CTO-PCI with unsuccessful CTO-PCI have reported variable outcomes. No systematic review or meta-analysis has been performed after stenting became the default strategy for CTO-PCI. Searching major electronic databases, 64 studies were identified using the keywords "CTO," "PCI," and "mortality." Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses method, 13 studies met the criteria for inclusion in the present meta-analysis. The short-term (≤30 days) and long-term (≥1 year) mortality outcomes were analyzed comparing successful CTO-PCI and unsuccessful CTO-PCI. Coronary perforation and its association with CTO-PCI success was analyzed. A significant reduction in short-term mortality was noted with successful CTO-PCI compared to unsuccessful CTO-PCI (odds ratio 0.218, 95% confidence interval 0.095 to 0.498, Z = -3.61, p <0.001). A similar, significant reduction in long-term mortality was noted with successful CTO-PCI compared to unsuccessful CTO-PCI (odds ratio 0.391, 95% confidence interval 0.311 to 0.493, Z = -7.957, p <0.001). A significant association was present between coronary perforation and unsuccessful CTO-PCI (odds ratio 0.168, 95% confidence interval 0.104 to 0.271, Z = -7.333, p <0.001). In conclusion, successful CTO-PCI using a predominantly stent-based strategy is associated with a significant reduction in short- and long-term mortality compared to unsuccessful CTO-PCI. Coronary perforation was associated with CTO-PCI failure.

Comparison of five-year outcome of sirolimus-eluting stent implantation for chronic total occlusions versus for non-chronic total occlusion (from the j-Cypher registry)

The aim of this study was to evaluate the 5-year clinical outcomes of patients who underwent sirolimus-eluting stent implantation for chronic total occlusion (CTO). Among 10,759 patients treated exclusively with sirolimus-eluting stent in the j-Cypher registry, clinical outcomes were compared between 1,210 patients with revascularization for CTO and 9,549 patients with revascularization for non-CTO only. The cumulative 5-year incidence of all-cause death (13.2% vs 14.3%, p = 0.56) and definite stent thrombosis (1.9% vs 1.6%, p = 0.76) was similar between the 2 groups. The adjusted risk for CTO relative to non-CTO for all-cause death and definite stent thrombosis was insignificant (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.81 to 1.16, and HR 0.99, 95% CI 0.6 to 1.65, respectively). The cumulative incidence of target lesion revascularization was significantly higher in the CTO group (20.7% vs 14.8%, p <0.001). The adjusted risk for target lesion revascularization was significant (HR 1.31, 95% CI 1.13 to 1.52, p <0.001). In the subgroup analysis, the risk for CTO for all-cause death tended to be lower in the subgroup of patients with left ventricular ejection fractions ≤40% (HR 0.68, 95% CI 0.45 to 1.01, p = 0.053), while the risk was significantly higher in the subgroup of patients with end-stage renal disease without hemodialysis (HR 1.66, 95% CI 1.02 to 2.70, p = 0.04). In conclusion, sirolimus-eluting stent implantation for CTO appears to be as safe as that for non-CTO for up to 5 years, except for the modestly elevated risk for target lesion revascularization and the higher risk for all-cause death in patients with end-stage renal disease without hemodialysis.

Late (3 years) follow-up of successful versus unsuccessful revascularization in chronic total coronary occlusions treated by drug eluting stent

The success rate of recanalization of coronary chronic total occlusion (CTO) has improved in recent years, but the clinical benefit associated with successful CTO recanalization in the drug-eluting stent (DES) era is not well known. A cohort of 317 consecutive patients (mean age 65 ± 10, 84% men) with CTOs (defined as Thrombolysis In Myocardial Infarction [TIMI] flow grade 0 and duration >3 months) of native coronary vessels in which percutaneous coronary intervention was attempted was enrolled from June 2005 to March 2009. All successful procedures (196 patients) were performed by DES implantation. The incidence of major adverse cardiac events (MACEs; a composite of cardiac death, myocardial infarction, and repeat revascularization) was assessed during a mean follow-up period of 3 years. MACE predictors were assessed in clinical, angiographic, and procedural data, including procedural success. Patients with successful percutaneous coronary intervention experienced a significantly lower MACE rate compared to those with failed procedures (17 [9%] vs 32 [26%], p = 0.008). Patients with multivessel disease experienced MACEs more frequently than those with single-vessel disease (45 [22%] vs 4 [4%], p = 0.002). On multiple Cox regression analysis, the presence of multivessel disease and CTO opening failure were independent predictors of MACEs (hazard ratio 2.31, 95% confidence interval 1.17 to 4.96, p = 0.01, and hazard ratio 1.81, 95% confidence interval 1.33 to 4.12, p = 0.02, respectively). The worst prognosis was confined to patients with multivessel disease and failed procedures (hazard ratio 2.73, 95% confidence interval 1.21 to 3.92, p = 0.03). In conclusion, successful recanalization of CTOs with DES translates into a reduction of the 3-year MACE rate compared to failed procedures, and the worst prognosis is observed in patients with failed procedures and multivessel disease, a notion that might be taken into account in the management of patients with coronary CTOs.