Chronic total coronary occlusions in patients with stable angina pectoris: impact on therapy and outcome in present day clinical practice

Retrograde Approach is as Effective and Safe as Antegrade Approach in Contemporary Percutaneous Coronary Intervention for Chronic Total Occlusion: A Taiwan Single-Center Registry Study

BACKGROUND

In percutaneous coronary intervention (PCI) for chronic total occlusion (CTO), most experts regard the antegrade approach as the default initial strategy, reserving the retrograde approach for reattempts following antegrade failure. In this study, we aimed to compare the efficacy and safety between the antegrade and retrograde approaches in CTO PCI.

RESULTS

Between 2012 and 2013, patients that underwent 321 consecutive attempts by high-volume operators (> 75 total CTO PCI cases during the period) in a tertiary university-affiliated hospital were enrolled. The antegrade approach was used in 152 patients, and retrograde in 169 patients. The duration of occlusion was significantly longer and the J-CTO score higher in the retrograde group. Technical success was achieved in 148 patients of the antegrade group (97.4%), and 163 patients in the retrograde group (96.4%) (p = 0.75). A major procedural complication occurred in 3 patients of the antegrade group (2.0%) and in 6 patients of the retrograde group (3.6%) (p = 0.51). In-hospital major adverse cardiac events (MACE) rates (antegrade 0.7%, n = 152; retrograde 0.6%, n = 169) were comparable. The procedure and fluoroscopy times were significantly longer, with more radiation exposure and contrast medium consumption, in the retrograde group. In the retrograde group, similar success, procedural complication and in-hospital MACE rates were achieved in the 3 collateral subgroups.

CONCLUSIONS

In selected cases and with highly experienced operators, retrograde approach in CTO PCI is as effective and safe as antegrade approach at the expense of longer procedure time, more radiation exposure and contrast medium consumption. For retrograde approach, either septal, epicardial or AV groove collaterals can be used with similarly success, complication and in-hospital MACE rates.

Chronic total coronary occlusion recanalization: Current techniques and new devices

Percutaneous coronary intervention (PCI) of total chronic coronary occlusion (CTO) still remains a major challenge. The prevalence of a CTO has been reported to be up to 30% among patients with a clinical indication for coronary angiography. Progress has been made with further advanced interventional techniques and continuously sophisticated interventional tools. Nevertheless the number of interventions carried out to recanalize a CTO is less than 10% of all procedures. Benefits of a successful CTO recanalization include relief of angina pectoris and ischemia-related dyspnea, substantial improvement in left ventricular function and, avoidance of surgery treatment. A vast variety of new CTO PCI techniques and materials has been introduced into clinical practise and pushed success rates of reopening a CTO up to around 90% in experienced hands. Particulary the introduction of the retrograde technique was a milestone. New developed microcatheters and special polymer coated wires allow to recanalize via small collaterals and vessels. Other tools such as intravascular ultrasound (IVUS) and multislice computertomography (MSCT) help to identify the anatomy and the characteristic of the lesions. Any invasive cardiac center should adopt CTO PCI procedures as standard therapy.

Objective

This review wants to assess and describe the latest development in CTO recanalization strategies.

CMR Guidance for Recanalization of Coronary Chronic Total Occlusion

OBJECTIVES

This study explored whether cardiac magnetic resonance (CMR) could help select patients who could benefit from revascularization by identifying inducible myocardial ischemia and viability in the perfusion territory of the artery with chronic total occlusion (CTO).

BACKGROUND

The benefit of revascularization using percutaneous coronary intervention (PCI) in CTO is controversial. CMR offers incomparable left ventricular (LV) systolic function assessment in addition to potent ischemic burden quantification and reliable myocardial viability analysis. Whether CMR guided CTO revascularization would be helpful to such patients has not yet been explored fully.

METHODS

A prospective study of 50 consecutive CTO patients was conducted. Of 50 patients undergoing baseline stress CMR, 32 (64%) were selected for recanalization based on the presence of significant inducible perfusion deficit and myocardial viability within the CTO arterial territory. Patients were rescanned 3 months after successful CTO recanalization.

RESULTS

At baseline, myocardial perfusion reserve (MPR) in the CTO territory was significantly reduced compared with the remote region (1.8 ± 0.72 vs. 2.2 ± 0.7; p = 0.01). MPR in the CTO region improved significantly after PCI (to 2.3 ± 0.9; p = 0.02 vs. baseline) with complete or near-complete resolution of CTO related perfusion defect in 90% of patients. Remote territory MPR was unchanged after PCI (2.5 ± 1.2; p = NS vs. baseline). The LV ejection fraction increased from 63 ± 13% to 67 ± 12% (p < 0.0001) and end-systolic volume decreased from 65 ± 38 to 56 ± 38 ml (p < 0.001) 3 months after CTO PCI. Importantly, despite minimal post-procedural infarction due to distal embolization and side branch occlusion in 8 of 32 patients (25%), the total Seattle Angina Questionnaire score improved from a median of 54 (range 45 to 74) at baseline to 89 (range 77 to 98) after CTO recanalization (p < 0.0001).

CONCLUSIONS

In this small group of patients showing CMR evidence of significant myocardial inducible perfusion defect and viability, CTO recanalization reduces ischemic burden, favors reverse remodeling, and ameliorates quality of life.

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.

Procedural outcomes of chronic total occlusion percutaneous coronary intervention: a report from the NCDR (National Cardiovascular Data Registry)

OBJECTIVES

The aim of this study was to describe contemporary frequency, predictors, and outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in the United States.

BACKGROUND

CTO PCI can provide significant clinical benefits, yet there is limited information on its success and safety in unselected patient populations.

METHODS

We analyzed the frequency and outcomes of CTO PCI compared with non-CTO PCI in elective patients, and of successful versus failed CTO PCI between July 1, 2009, and March 31, 2013, in the National Cardiovascular Data Registry CathPCI Registry. Generalized estimating equations logistic regression modeling was used to generate independent variables associated with procedural success and procedural complications.

RESULTS

During the study period, CTO PCI represented 3.8% of the total PCI volume for stable coronary artery disease (22,365 of 594,510). Overall, patients undergoing CTO PCI required greater contrast volume and longer fluoroscopy time and had lower procedural success (59% vs. 96%, p < 0.001) and higher major adverse cardiac event (1.6% vs. 0.8%, p < 0.001) rates than non-CTO PCI patients. On multivariable analysis, several parameters (including older age, current smoking, previous myocardial infarction, previous coronary artery bypass graft, previous peripheral arterial disease, previous cardiac arrest, right coronary artery CTO target vessel, and less operator experience) were associated with a lower likelihood of CTO PCI procedural success, whereas operators' annual CTO PCI volume was associated with improved success without a significant increase in major complications.

CONCLUSIONS

CTO PCI is currently performed infrequently in the United States for stable coronary artery disease and is associated with lower procedural success and higher complication rates compared with non-CTO PCI. Procedural success was associated with several patient factors and operator experience.

Analysis of Plaque Composition in Coronary Chronic Total Occlusion Lesion Using Virtual Histology-Intravascular Ultrasound

Background and Objectives

Success rates of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have recently been reported to range from 80% to 90%. A better understanding of the pathologic characteristics of the CTO lesion may helpful to improving CTO PCI success rates. We evaluated the CTO lesion in patients with stable angina (SA) by virtual histology-intravascular ultrasound (VH-IVUS).

Subjects and Methods

The study population consisted of 149 consecutive patients with SA underwent VH-IVUS examination. We analyzed demographic and VH-IVUS findings in 22 CTO patients (17 males; mean, 62.3 years old) compared with 127 non-CTO patients (82 males; mean, 61.3 years old).

Results

A significantly lower ejection fraction (57.6±13.0% vs. 65.4±8.8%, p=0.007) was detected in the CTO group compared with the non-CTO group. Reference vessel lumen area of the proximal and distal segment was significantly less in CTO group than in non-CTO group. The lesion length of the CTO group was significantly longer than those of the non-CTO group (24.4±9.6 mm vs. 17.2±7.4 mm, p<0.001). Total atheroma volume (224±159 mm³ vs. 143±86 mm³, p=0.006) and percent atheroma volume (63.2±9.6% vs. 55.8±8.5%, p=0.011) of the CTO group were also significantly greater than those of non-CTO group. However, the lesion length adjusted plaque composition of the CTO group was not significantly different compared with that of the non-CTO group.

Conclusion

CTO lesions had a longer lesion length and greater plaque burden than the non-CTO lesion in patients with SA. However, lesion length adjusted plaque composition showed similar between the two groups. These results support that plaque characteristics of CTO lesions are similar to non-CTO lesions in patients with SA.

Myths to Debunk to Improve Management, Referral, and Outcomes in Patients With Chronic Total Occlusion of an Epicardial Coronary Artery

A chronic total occlusion (CTO) is defined as an occlusive (100% stenosis) coronary lesion with anterograde Thrombolysis In Myocardial Infarction 0 flow for at least 3 months. CTOs are common in patients referred for coronary angiography (up to 33%) and are associated with angina, impaired quality of life, and reduced survival. Unfortunately, CTO percutaneous coronary intervention continues to be underperformed worldwide (10% to 15% at most institutions, ∼30% where expert operators are available). The aim of this study was to address common fallacies pertaining to CTOs among cardiologists by providing a concise review of pertinent previously published reports along with an update on safety and efficacy of state-of-the-art CTO percutaneous coronary intervention techniques.

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.

Real-World Use and Appropriateness of Coronary Interventions for Chronic Total Occlusion (from a Japanese Multicenter Registry)

Little is known about the outcomes and indications of chronic total occlusion percutaneous coronary intervention (CTO-PCI), other than in high-volume centers. We sought to provide a real-world overview of the clinical outcomes and appropriateness of PCI for CTO. The analysis included 4,950 consecutive PCIs for nonacute indications registered in the multicenter Japanese PCI registry in collaboration with the US National Cardiovascular Data Registry (Cath-PCI). Data included demographics, clinical outcomes (procedural success and complication rates), and the indication appropriateness, based on the 2012 appropriate use criteria for revascularization. The overall procedural success and major adverse cardiac event rates of 501 cases with CTO-PCI (10.1%) were 76% and 3.2%, respectively. Based on the criteria, mapping failures occurred in 2,521 procedures; the remaining 2,429 PCIs were successfully mapped. The CTO-PCIs were performed for more appropriate indications than PCIs for lesions without CTO. The rate of inappropriate indications was significantly lower in CTO-PCIs than in non-CTO-PCIs (23.0% vs 31.4%, p = 0.04). Only 17% of CTO-PCIs were directly assigned to CTO-specific scenarios because such scenarios are only intended for "Lone" CTO; the rest of the CTO-PCI cases were secondarily mapped to non-CTO-specific scenarios. In conclusion, as many as 10% of the elective PCIs were performed for CTO lesions in a contemporary multicenter Japanese PCI registry; CTO-PCI was associated with lower procedural success and higher complication rates than non-CTO-PCI. Its indication was relatively appropriate; however, our findings emphasize the need for more rigorous evaluation in terms of the present insufficient CTO-related clinical scenarios.

CTO pathophysiology: how does this affect management?

Chronic total occlusion (CTO) pathophysiology has been described in a few, small studies using post mortem histology, and more recently, in vivo intravascular ultrasound (IVUS) to analyse the constituents of occluded segments. Recent improvements in equipment and techniques have revealed new insights into physical characteristics of occluded coronaries, which in turn enable predictable procedural success. The purpose of this review is to consider the published evidence describing CTO pathophysiology from the perspective of the hybrid algorithm approach to CTO PCI.

Methods: Literature searches using “Chronic Occlusion”, “angioplasty”, and” pathology” as keywords. Further searches on “coronary” “collateral”, “Viability”. Bibliographies were scrutinised for further key publications in an iterative process. Papers describing animal models were excluded.

Value of Hybrid Imaging with PET/CT to Guide Percutaneous Revascularization of Chronic Total Coronary Occlusion

Chronic total coronary occlusions (CTO) are documented in approximately one fifth of diagnostic invasive coronary angiographies (ICA). Percutaneous coronary interventions (PCI) of CTO are challenging and are accompanied by higher complication and lower success rates in comparison with non-CTO PCI. Scrutinous evaluation of ischemia and viability to justify percutaneous revascularization is therefore of importance to select eligible patients for such a procedure. Furthermore, knowledge of the anatomical features of the occlusion may predict the chances of success of PCI CTO and could even guide the procedural strategy to augment the likelihood of recanalization. Positron emission tomography (PET) is unequivocally accepted as the reference standard for ischemia and viability testing, whereas coronary computed tomography angiography (CCTA) currently allows for non-invasive detailed three-dimensional imaging of the coronary anatomy that adds morphological information over two-dimensional ICA. Hybrid PET/CT could therefore be useful for optimal patient selection as well as procedural planning. This review discusses the potential value of PET/CT to guide PCI in CTOs.

Physiologic significance of coronary collaterals in chronic total occlusions

Chronic total occlusions (CTOs) are commonly found in patients with coronary artery disease, and a system of collateral connections are found in almost all of these patients. These collateral vessels serve to prevent myocardial necrosis but are not sufficient to prevent myocardial ischemia during exercise. Unfortunately, the presence of well-developed collaterals has been used as argument against CTO revascularization. Many continue to falsely believe that these patients are "protected" by collaterals and, therefore, CTO recanalization is not indicated. Our knowledge of the physiologic significance of coronary collaterals has increased significantly over the past several years. Studies utilizing coronary pressure and flow velocity have answered a number of basic physiologic questions. We therefore sought to review the evidence for coronary collateral flow and their clinical significance in patients with CTOs.

The role of coronary collaterals in chronic total occlusions

A chronic total occlusion (CTO) describes a completely occluded coronary artery. This type of lesion is found in about 18% of all significant lesions in patients with coronary artery disease. A system of collateral connections are observed in almost all of these lesions, which have the capacity to prevent myocardial necrosis and may even uphold metabolic supply to the territory distal to an occlusion to maintain full contractile capacity. During exercise these collaterals are limited in their functional reserve, and more than 90% of patients with a well collateralized occlusion will experience ischemia. in the absence of ideal animal models that mimic the human collateral circulation, we need to rely on studies in man. The knowledge of collateral physiology in man has increased considerably over the past two decades with the advent of intracoronary sensors of coronary pressure and flow velocity. A number of basic physiologic questions have been answered by these studies. The blood supply through coronary arteries depends on a complex array of in general serial resistance systems, with an additional array of multiple parallel resistances on the collateral level. There seems to be a great interindividual variability in the ability to recruit preformed collateral connections in the case of an epicardial occlusion. Collateral function can develop to a similar functional level in patients post myocardial infarction with large akinetic territories as it does in patients with normal preserved regional function. The presence of viability is thus not a prerequisite for collateral development. The question of practical relevance in the era of interventional therapy of chronic occlusions is also, whether a patient with coronary artery disease will remain protected by collaterals after removing the obstruction in the collateralized artery, or whether collaterals regress and lose their functional capacity. Both developments are observed again mainly depending of individual predisposition.

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.

Prevalence and management of coronary chronic total occlusions in a tertiary Veterans Affairs hospital

OBJECTIVES

We sought to determine the contemporary prevalence and management of coronary chronic total occlusions (CTO) in a veteran population.

BACKGROUND

The prevalence and management of CTOs in various populations has received limited study.

METHODS

We collected clinical and angiographic data in consecutive patients that underwent coronary angiography at our institution between January 2011 and December 2012. Coronary artery disease (CAD) was defined as ≥50% diameter stenosis in ≥1 coronary artery. CTO was defined as total coronary artery occlusion of ≥3 month duration.

RESULTS

Among 1,699 patients who underwent angiography during the study period, 20% did not have CAD, 20% had CAD and prior coronary artery bypass graft surgery (CABG), and 60% had CAD but no prior CABG. The prevalence of CTO among CAD patients with and without prior CABG was 89 and 31%, respectively. Compared to patients without CTO, CTO patients had more co-morbidities, more extensive CAD and were more frequently referred for CABG. Percutaneous coronary intervention (PCI) to any vessel was performed with similar frequency in patients with and without CTO (50% vs. 53%). CTO PCI was performed in 30% of patients without and 15% of patients with prior CABG with high technical (82 and 75%, respectively) and procedural success rates (80 and 73%, respectively).

CONCLUSIONS

In a contemporary veteran population, coronary CTOs are highly prevalent and are associated with more extensive co-morbidities and higher likelihood for CABG referral. PCI was equally likely to be performed in patients with and without CTO.

Therapeutic angiogenesis with VEGF164 for facilitation of guidewire crossing in experimental arterial chronic total occlusions

AIMS

Percutaneous revascularisation of chronic total occlusions (CTO) is limited by failure of guidewire crossing. Neovascularisation within the proximal CTO segment may be important for guidewire crossing and dramatically declines in CTO beyond six weeks of age. The aims of the current study were to determine whether local delivery of a pro-angiogenic growth factor increases neovascularisation in mature CTO and facilitates guidewire crossings.

METHODS AND RESULTS

CTO (n=51) were created in the femoral arteries of 44 New Zealand white rabbits using the thrombin injection model. At 12 weeks, CTO were treated with poly-lactic-glycolic-acid (PLGA) microspheres containing either bovine serum albumin (BSA) (n=15) or recombinant mouse VEGF164 (n=14), or received no intervention (controls, n=12). Contrast-enhanced magnetic resonance angiography (CEMRA) was performed prior to treatment and at three weeks post treatment. Animals were sacrificed at three weeks post treatment and arterial samples were excised for micro-computed tomography imaging (µCT) and histologic morphometric analysis. Guidewire crossing was assessed at three weeks post treatment in an additional 10 VEGF164-treated CTO. In comparison to BSA-treated and control non-intervened CTO, VEGF164-treated CTO showed a significant increase in relative blood volume index in the proximal segment of the CTO lesion as determined by CEMRA and by µCT. Histologic measurements of microvessel area were also higher in VEGF164-treated CTO. Guidewire crossing across the proximal fibrous cap was successful in eight out of 10 VEGF164-treated CTO.

CONCLUSIONS

Angiogenic therapy appears to be a promising strategy to improve neovascularisation and guidewire crossing rates in CTO.

Reversal of ischemia of donor artery myocardium after recanalization of a chronic total occlusion

BACKGROUND

Case reports have shown that an intermediate stenosis in the donor artery collateralizing the myocardium of a chronic total occlusion (CTO) can produce an ischemic fractional flow reserve (FFR) value which may revert to non-ischemic with CTO revascularization.

METHODS

A consecutive series of patients with severe angina in which a donor artery with intermediate stenosis (30-70%) had FFR measured before and after successful CTO recanalization were studied.

RESULTS

Fourteen of 50 consecutive CTO patients with successful PCI fulfilled the study criteria. Eight had CTO of the right coronary artery (RCA), three circumflex (LCx), and three RCA and LCx. Left anterior descending artery was the donor artery in 13 and LCx in 1 patient. Of nine donor ischemic FFR patient's pre-PCI, six reverted to non-ischemic (FFR pre-PCI 0.76 ± 0.04 and 0.86 ± 0.03 post-PCI). Five patients had normal FFR in the donor artery pre- and post-CTO PCI.

CONCLUSIONS

In patients with a CTO and an intermediate donor artery stenosis, the frequency of ischemia in the donor artery territory is relatively high and often normalized by successful CTO recanalization. These data recommend recanalizing the CTO first whenever possible as a preferred therapeutic strategy to avoid the need for PCI to the donor artery or multivessel bypass surgery.

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.

Rationale for Percutaneous Intervention of CTO

Chronic total occlusion accounts for 15% of cases during diagnostic angiography with higher referral rate to surgical revascularization. With contemporary strategies and techniques, the success rate with experienced operators can exceed 90%. Currently available observational studies in carefully selected patient populations show evidence of a trend toward symptom relief; improvement in quality of life, left ventricular function, and mortality; and improved tolerance toward future ischemic events. Lack of randomized controlled trials comparing current optimal medical management with percutaneous coronary intervention for chronic total occlusion is a major barrier to widespread adaptation of this advanced complex interventional technique.

Current perspectives on coronary chronic total occlusions: the Canadian Multicenter Chronic Total Occlusions Registry

OBJECTIVES

The purpose of this study was to determine the prevalence, clinical characteristics, and management of coronary chronic total occlusions (CTOs) in current practice.

BACKGROUND

There is little evidence in contemporary literature concerning the prevalence, clinical characteristics, and treatment decisions regarding patients who have coronary CTOs identified during coronary angiography.

METHODS

Consecutive patients undergoing nonurgent coronary angiography with CTO were prospectively identified at 3 Canadian sites from April 2008 to July 2009. Patients with previous coronary artery bypass graft surgery or presenting with acute ST-segment elevation myocardial infarction were excluded. Detailed baseline clinical, angiographic, electrocardiographic, and revascularization data were collected.

RESULTS

Chronic total occlusions were identified in 1,697 (18.4%) patients with significant coronary artery disease (>50% stenosis in ≥1 coronary artery) who were undergoing nonemergent angiography. Previous history of myocardial infarction was documented in 40% of study patients, with electrocardiographic evidence of Q waves corresponding to the CTO artery territory in only 26% of cases. Left ventricular function was normal in >50% of patients with CTO. Half the CTOs were located in the right coronary artery. Almost half the patients with CTO were treated medically, and 25% underwent coronary artery bypass graft surgery (CTO bypassed in 88%). Percutaneous coronary intervention was done in 30% of patients, although CTO lesions were attempted in only 10% (with 70% success rate).

CONCLUSIONS

Chronic total occlusions are common in contemporary catheterization laboratory practice. Prospective studies are needed to ascertain the benefits of treatment strategies of these complex patients.

Ventricular Arrhythmias Among Implantable Cardioverter-Defibrillator Recipients for Primary Prevention

Background—

An implantable cardioverter-defibrillator (ICD) is the therapy of choice for primary prevention in patients with ischemia who are at risk for sudden cardiac death (SCD). One third of patients with significant coronary disease have chronic total coronary occlusion (CTO), which is associated with long-term mortality in patients with previous myocardial infarction. However, the impact of CTO on the occurrence of ventricular arrhythmias and long-term mortality in ICD recipients remains unknown.

Methods and Results—

All consecutive patients with coronary artery disease receiving ICD therapy for the prevention of SCD were included in the study. Among other characteristics, the existence of CTO was assessed. During follow-up, the occurrence of appropriate device delivery because of ventricular arrhythmias as well as mortality were noted. A total of 162 patients (mean age, 62±9 years; 93% men) with an ICD were included and followed for a median of 26 months (interquartile range, 12–42). At least 1 CTO was present in 71 (44%) patients. Appropriate device therapy was detected in 18% of the patients during the follow-up. The presence of CTO was associated with higher ventricular arrhythmia and mortality rates (log-rank test, <0.01). Multivariable analysis revealed that CTO was independently associated with appropriate ICD intervention (hazard ratio, 3.5; P =0.003).

Conclusions—

In patients with ischemic heart disease receiving ICDs for primary prevention of SCD, CTO is an independent predictor for the occurrence of ventricular arrhythmias and has an adverse impact on long-term mortality.

Imaging of homeostatic, neoplastic, and injured tissues by HA-based probes

An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, (99m)Tc-HA, and iodine-HA, (125)I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver ((99m)Tc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury ((125)I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues.

Everolimus-eluting stents for treatment of chronic total coronary occlusions

BACKGROUND

After successful recanalization of a coronary chronic total occlusion (CTO) the risk for restenosis and subsequent need for repeat intervention is high. Everolimus-eluting stents (EESs) were associated with low rates of restenosis, reintervention and stent thrombosis in non-occluded lesions. We sought to determine the antiproliferative impact of the everolimus-eluting Xience V stent in CTOs.

METHODS

Fifty-three patients with a CTO in a native coronary artery were included. CTO was defined as a duration of occlusion ≥3 months and thrombolysis in myocardial infarction 0 flow. EESs were exclusively implanted to completely cover the occluded and adjacent stenotic segments. Dual antiplatelet therapy was prescribed for 6 months. Follow-up angiography was scheduled at 6 months. Clinical follow-up was done at 12 months. The primary endpoint was late loss at the initial occlusion site. Secondary clinical endpoint was a composite of cardiac death, myocardial infarction not clearly attributable to a non-target vessel and target lesion revascularization.

RESULTS

Mean occlusion length was 24 ± 17 mm, ranging from 4 to 74 mm. Mean stent length was 79 ± 36 mm, ranging from 18 to 158 mm. Reference diameter was 3.27 ± 0.58 mm. Late loss at the initial occlusion site was 0.22 ± 0.69 mm. There were six (11%) binary restenosis with a target lesion reintervention in three (6%) patients. There was no death, myocardial infarction or stent thrombosis within 12 months.

CONCLUSION

In patients with successful recanalization of complex CTOs the use of EESs results in a low angiographic late loss and restenosis rate without stent thrombosis throughout 12 months follow-up.

[Treatment strategies for chronic total occlusion: current status and outlook]

The present article discusses the current status of treatment strategies for chronic total occlusion (CTO) and the prospects offered by new therapies. The indication for revascularisation recognized in the current European guidelines includes the presence of typical symptoms and evidence of ischemia of over 10% of the total myocardium, while in patients with multiple vascular diseases the aim is complete revascularisation. Although the vast majority of patients with CTO fulfil these criteria, they are currently not receiving interventional treatment as frequently as expected. The reasons often given for this include the low success rates and high recurrence rates. However, both problems have been improved by drug-eluting stents (DES) on the one hand and by wire techniques and strategies on the other, such that results almost comparable with non-occluded coronary lesions can be achieved. While more advanced approaches like retrograde recanalization should be restricted to specialized centres, marked improvements can be achieved even without these special techniques by means of consistent further training and the application of modern techniques. Despite the aggressiveness of these approaches to pass through an occluded artery, the complication rate is not higher than with non-occluded lesions when the specific complications of recanalization are avoided in a careful approach. Further technical improvements are expected with the use of modern imaging techniques such as intravascular ultrasound and high-resolution CT imaging of coronary arteries.

Contemporary success and complication rates of percutaneous coronary intervention for chronic total coronary occlusions: results from the ALKK quality control registry of 2006

AIMS

Despite successful prevention of lesion recurrence by drug-eluting stents (DES), and the advancement in procedural techniques in the treatment of chronic total coronary occlusions (CTO), the number of CTOs treated by percutaneous coronary intervention (PCI) is still low as compared to their prevalence. This study aims to assess the outcome of PCI for CTOs in a contemporary survey of PCI in interventional centres in Germany.

METHODS AND RESULTS

The basis of this analysis is the 2006 quality assessment database of PCI conducted by the ALKK (working group of cardiology centres). Thirty-five centres contributed to this database, representing about 10% of all interventional centres of Germany. From a total of 20,502 patients, 8,882 patients with stable angina were selected. Of these 674 patients (7.6%) underwent PCI for a CTO. Their procedural characteristics and the hospital outcome were compared with patients treated for non-occlusive lesions. As compared to non-occlusive lesions, less patients underwent ad hoc PCI for a CTO. The fluoroscopy time was almost double of that in non-occlusive lesions, and contrast usage was significantly higher. The success rate was 60.1% as compared to 97.3% (p<0.001). Severe intraprocedural and in-hospital complications were similar for CTO and non-CTO lesions. Almost all patients with a CTO received a stent; DES were used in 53.4%, which was higher than the rate in non-CTO lesions (38.9%; p<0.001).

CONCLUSIONS

Although the success rate for PCI in CTOs is still well below that in non-occlusive lesions, this procedure is safe, encouraging its wider application. The low rate of DES use did not reflect the evidence for DES in CTOs.

Poor coronary collateral vessel development in patients with mild to moderate renal insufficiency

BACKGROUND

The development of coronary collaterals is crucial to survival through acute ischemia. Mild to moderate loss of renal function has been suggested to play a role in this event, but evidential data are scarce. The aim of this study was to investigate the relationship between mild to moderate renal insufficiency and coronary collateral development in patients with chronic total coronary artery occlusion.

METHODS AND RESULTS

A total of 83 patients with mild to moderate loss of renal function (30 mL/min/1.73 m(2) ≤ eGFR < 90 mL/min/1.73 m(2)) with chronic total coronary artery occlusion were included in our study. The collateral circulation was graded according to Rentrop classification and the function of collateral circulation was graded according to Werner collateral connection (CC) grades. Compared to patients with good collateral circulation (Rentrop = 2,3), eGFR was found to be lower in those patients with poor coronary collateral circulation (Rentrop = 0,1) (63.30 ± 10.51 vs. 54.13 ± 10.56, P = 0.02). eGFR was also found to be lower in poorly functioning coronary collateral circulation (CC = 0,1) than in efficiently functioning coronary collateral circulation (CC = 2) (55.22 ± 9.98 vs. 66.28 ± 9.16, P = 0.03). Multiple logistic regression analysis showed that low eGFR was independently associated with poor coronary collateral circulation (Rentrop = 0,1, 95% CI, 0.09-1.09, P = 0.044) and poor function of coronary collateral circulation (CC = 0,1, 95% CI, 0.02-0.17, P = 0.02).

CONCLUSIONS

Lower eGFR is associated with poorer coronary collateral vessel development in patients experiencing mild to moderate renal insufficiency. Moreover, eGFR represents an independent factor affecting coronary collateral vessel development.