Transient impairment of vasomotion function after successful chronic total occlusion recanalization

Self-Apposing Stents in Coronary Chronic Total Occlusions: A Pilot Study

OBJECTIVES

This pilot study assessed the 12-month angiographic and clinical outcomes of self-apposing (SA) stents in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

BACKGROUND

Self-apposing (SA) stents may decrease incomplete strut apposition and stent strut coverage that are common after CTO PCI.

METHODS

We compared 20 patients who underwent CTO PCI using SA drug-eluting stents (DESs) with 20 matched control patients who underwent CTO PCI using balloon-expandable (BE)-DESs. All patients were followed up clinically for 12 months and had coronary angiography with optical coherence tomography at the end of the follow-up period. The primary end points were stent strut malapposition and strut coverage. The secondary end point was composite major adverse cardiovascular events (MACEs) at 12 months.

RESULTS

Both groups had high prevalence of diabetes mellitus, and most of the treated lesions were complex, with 62% having a J-CTO score of ≥3. All CTO PCI techniques were allowed for recanalisation, and 75% of the procedures were guided by intravascular ultrasound. At 12 months, the SA-DES group had fewer malapposed struts (0% [interquartile range (IQR) 0%-0%] vs 4.5% [IQR 0%-20%]; p<0.001) and uncovered struts (0.08% [IQR 0%-1.6%] vs 8.2% [IQR 0%-16%]; p<0.001). However, they showed significantly higher rates of MACEs due to clinically-driven target lesion revascularisation (45% vs 15%; p=0.038).

CONCLUSIONS

In this pilot study, compared with conventional BE-DESs, SA-DESs used in CTO PCI were associated with fewer malapposed and uncovered stent struts but also with significantly higher rates of in-stent restenosis and MACEs, mainly caused by clinically driven target lesion revascularisation.

Clinical Outcome of Paclitaxel-Coated Balloon Angioplasty Versus Drug-Eluting Stent Implantation for the Treatment of Coronary Drug-Eluting Stent In-Stent Chronic Total Occlusion

AIMS

In-stent chronic total occlusion (IS-CTO) represents a unique challenge for percutaneous coronary intervention. Whether the optimal treatment for IS-CTO is angioplasty with paclitaxel-coated balloons (PCBs) or repeat stenting with drug-eluting stents (DESs) is unclear. We aimed to evaluate the long-term clinical outcome of PCB angioplasty and DES repeat stenting for DES IS-CTO.

METHODS

We retrospectively included patients with DES IS-CTO who underwent successful PCB angioplasty or DES repeat stenting from January 2016 to December 2019. The primary endpoints were major adverse cardiac events (MACEs), including cardiac death, myocardial infarction, and target lesion revascularization (TLR). Cox proportional hazards model was performed to compare the risk of MACEs between PCB angioplasty and DES repeat stenting, and to further explore the prognostic factors of patients with DES IS-CTO.

RESULTS

A total of 214 patients with DES IS-CTO were enrolled: 78 patients (36.4%) treated with PCB and 136 patients (63.6%) treated with DES respectively. The median follow-up was 1160 days, and MACEs were observed in 28.2% of patients with PCB angioplasty versus 26.5% of patients with DES repeat stenting (P = 0.784), mainly driven by TLR (21.8% vs. 19.9%, P = 0.735). There was no significant difference in the risk of MACEs between the PCB group and the DES group (hazard ratio [HR] 1.25, 95% confidence interval [CI] 0.64-2.46, P = 0.512). Multivariate Cox analysis revealed that chronic kidney disease and ≥ 3 stent layers in the lesion were independent predictors of MACEs, while switching to another antiproliferative drug was an independent protective factor (all P < 0.05).

CONCLUSIONS

PCB angioplasty was an effective alternative treatment strategy for DES IS-CTO, which had similar long-term outcomes to DES repeat stenting in contemporary practice, but both were accompanied by a high rate of long-term MACEs. Improving the poor prognosis of patients with DES IS-CTO remains a challenge.

The role of intravascular imaging in chronic total occlusion percutaneous coronary intervention

Chronic total occlusions (CTOs) represent the most complex subset of coronary artery disease and therefore careful planning of CTO percutaneous coronary recanalization (PCI) strategy is of paramount importance aiming to achieve procedural success, and improve patient's safety and post CTO PCI outcomes. Intravascular imaging has an essential role in facilitating CTO PCΙ. First, intravascular ultrasound (IVUS), due to its higher penetration depth compared to optical coherence tomography (OCT), and the additional capacity of real-time imaging without need for contrast injection is considered the preferred imaging modality for CTO PCI. Secondly, IVUS can be used to resolve proximal cap ambiguity, facilitate wire re-entry when dissection and re-entry strategies are applied and most importantly to guide stent deployment and optimization post implantation. The role of OCT during CTO PCI is currently limited to stent sizing and optimization, however, due to its high spatial resolution, OCT is ideal for detecting stent edge dissections and strut malapposition. In this review, we describe the use of intravascular imaging for lesion crossing, plaque characterization and wire tracking, extra- or intra-plaque, and stent sizing and optimization during CTO PCI and summarize the findings of the major studies in this field.

Distal Target Vessel Quality and Outcomes of Chronic Total Occlusion Percutaneous Coronary Intervention

BACKGROUND

Distal vessel quality is a key parameter in the global chronic total occlusion (CTO) crossing algorithm.

OBJECTIVES

The study sought to evaluate the association of distal vessel quality with the outcomes of CTO percutaneous coronary intervention.

METHODS

We examined the clinical and angiographic characteristics and procedural outcomes of 10,028 CTO percutaneous coronary interventions performed at 39 U.S. and non-U.S. centers between 2012 and 2022. A poor-quality distal vessel was defined as <2 mm diameter or with significant diffuse atherosclerotic disease. In-hospital major adverse cardiac events (MACE) included death, myocardial infarction, urgent repeat target vessel revascularization, tamponade requiring pericardiocentesis or surgery, and stroke.

RESULTS

A total of 33% of all CTO lesions had poor-quality distal vessel. When compared with good-quality distal vessels, CTO lesions with a poor-quality distal vessel had higher J-CTO (Japanese chronic total occlusion) scores (2.7 ± 1.1 vs 2.2 ± 1.3; P < 0.01), lower technical (79.9% vs 86.9%; P < 0.01) and procedural (78.0% vs 86.8%; P < 0.01) success, and higher incidence of MACE (2.5% vs 1.7%; P < 0.01) and perforation (6.4% vs 3.7%; P < 0.01). A poor-quality distal vessel was independently associated with technical failure and MACE. Poor-quality distal vessels were associated with higher use of the retrograde approach (25.2% vs 14.9%; P < 0.01) and higher air kerma radiation dose (2.4 [IQR: 1.3-4.0] Gy vs 2.0 [IQR: 1.1-3.5] Gy; P < 0.01).

CONCLUSIONS

A poor-quality distal vessel in CTO lesions is associated with higher lesion complexity, higher need for retrograde crossing, lower technical and procedural success, higher incidence of MACE and coronary perforation, and higher radiation dose.

Changes in absolute flow, myocardial resistance and FFR after chronic total occlusion percutaneous coronary intervention

BACKGROUND

Randomised studies of percutaneous coronary intervention (PCI) in patients with chronic total occlusion (CTO) have shown inconsistent outcomes, suggesting incomplete understanding of this cohort and their coronary physiology. To address this shortcoming, we designed a prospective observational study to measure the recovery of absolute coronary blood flow following successful CTO PCI Aims: We sought to identify patient and procedural characteristics associated with a favourable physiological outcome after CTO PCI.

METHODS

Consecutive patients with a CTO subtending viable myocardium underwent PCI utilising contemporary techniques and the hybrid algorithm. Immediately after PCI, and at 3-month follow-up, physiological measurements were performed utilising continuous thermodilution.

RESULTS

A total of 81 patients were included with a mean age of 63.6±8.9 years, and 66 (81.5%) were male. Physiological measurements of absolute coronary blood flow in the CTO vessel increased by 30% (p<0.001) and microvascular resistance reduced by 16% (p<0.001) from immediately post-CTO PCI to follow-up assessment. Fractional flow reserve increased by 0.02 (p=0.015) in the same period. Prior coronary artery bypass graft (CABG) and a higher estimated glomerular filtration rate (eGFR) were associated with a larger change in absolute flow. An extraplaque strategy was associated with a smaller change in absolute flow.

CONCLUSIONS

Post-CTO PCI, there is a continued augmentation in absolute coronary blood flow and reduction in microvascular resistance from baseline to follow-up at 3 months. Prior CABG and a higher baseline eGFR were predictors of a larger change in absolute coronary flow, whilst an extraplaque final wire path strategy predicted a smaller change. Lastly, the patient characteristics and comorbidities had a larger influence than procedural factors on the observed change in absolute flow.

Outcomes of Percutaneous Coronary Interventions for Long Diffuse Coronary Artery Disease with Extremely Small Diameter

BACKGROUND

The optimal percutaneous coronary intervention (PCI) strategy and clinical outcomes of long lesions with an extremely small residual lumen remain unclear. This study aimed to assess the efficacy of a modified stenting strategy for diffuse coronary artery disease (CAD) with an extremely small distal residual lumen.

METHODS

736 Patients who received PCI using second-generation drug-eluting stents (DES) ≥38 mm long were retrospectively included and categorized into an extremely small distal vessel (ESDV) group (≤2.0 mm) and a non-ESDV group (>2.0 mm) according to the maximal luminal diameter of the distal vessel (dsD_Max). A modified stenting technique was applied by landing an oversized DES in the distal segment with the largest luminal diameter and maintaining the distal stent edge partially expanded.

RESULTS

The mean dsD_Max and stent lengths were 1.7 ± 0.3 mm and 62.6 ± 18.1 mm in the ESDV group and 2.7 ± 0.5 mm and 59.1 ± 16.0 mm in non-ESDV groups, respectively. The acute procedural success rate was high in both the ESDV and non-ESDV groups (95.8% and 96.5%, p = 0.70) with rare distal dissection (0.3% and 0.5%, p = 1.00). The target vessel failure (TVF) rate was 16.3% in the ESDV group and 12.1% in the non-ESDV group at a median follow-up of 65 months without significant differences after propensity score matching.

CONCLUSIONS

PCI using contemporary DES with this modified stenting technique is effective and safe for diffuse CAD with extremely small distal vessels.

Data-independent acquisition proteomics reveals circulating biomarkers of coronary chronic total occlusion in humans

Introduction

The pathophysiology of coronary chronic total occlusion (CTO) has not been fully elucidated.

Methods

In the present study, we aimed to investigate the potential plasma biomarkers associated with the pathophysiologic progression of CTO and identify protein dynamics in the plasma of CTO vessels immediately after successful revascularization. We quantitatively analyzed the plasma proteome profiles of controls (CON, n = 10) and patients with CTO pre- and post- percutaneous coronary intervention (PCI) (CTO, n = 10) by data-independent acquisition proteomics. We performed enzyme-linked immunosorbent assay (ELISA) to further confirm the common DEPs in the two-group comparisons (CON vs. CTO and CTO vs. CTO-PCI).

Results

A total of 1936 proteins with 69 differentially expressed proteins (DEPs) were detected in the plasma of patients with CTO through quantitative proteomics analysis. For all these DEPs, gene ontology (GO) analysis and protein-protein interaction (PPI) analysis were performed. The results showed that most of the proteins were related to the negative regulation of proteolysis, regulation of peptidase activity, negative regulation of hydrolase activity, humoral immune response, and lipid location. Furthermore, we identified 1927 proteins with 43 DEPs in the plasma of patients with CTO vessels after immediately successful revascularization compared to pre-PCI. GO analysis revealed that the above DEPs were enriched in the biological processes of extracellular structure organization, protein activation cascade, negative regulation of response to external stimulus, plasminogen activation, and fibrinolysis. More importantly, we generated a Venn diagram to identify the common DEPs in the two-group comparisons. Seven proteins, ADH4, CSF1, galectin, LPL, IGF2, IgH, and LGALS1, were found to be dynamically altered in plasma during the pathophysiological progression of CTO vessels and following successful revascularization, moreover, CSF1 and LGALS1 were validated via ELISA.

Conclusions

The results of this study reveal a dynamic pattern of the molecular response after CTO vessel immediate reperfusion, and identified seven proteins which would be the potential targets for novel therapeutic strategies to prevent coronary CTO.

Why and How Should We Treat Chronic Total Occlusion? Evolution of State-of-the-Art Methods and Future Directions

Chronic total occlusions are considered the most complex coronary lesion in interventional cardiology. The absence of visible lumen on angiography obscures the vessel course and makes vessel wiring unlikely with conventional techniques. Often a source of severe ischemia, chronic occlusions are also markers of advanced atherosclerosis that brings other complex features including lesion length, bifurcations, calcification, adverse vessel remodelling, distal disease, and anatomic distortion from previous bypass grafting. Often advanced atherosclerosis is associated with patient characteristics like left ventricular dysfunction, previous coronary bypass surgery, or multivessel disease that increase procedural demands and hazards. To accommodate these challenges new techniques and dedicated technologies have been developed. When applied to appropriate patients, these advances have improved procedural success, safety, and outcomes. Our aim is to provide the general cardiologist with an overview of these advances that can serve as a basis for counselling patients considered for revascularization.

Intracoronary injection of nitroglycerine can prevent unnecessary percutaneous coronary intervention

Background

Despite the recommendation of the current guidelines, intracoronary administration of nitroglycerine during coronary angiography is often neglected. We investigated the effect of intra-coronary nitroglycerin on the relief of coronary artery stenosis in the candidates for percutaneous coronary intervention (PCI).

Methods

We included patients with angina pectoris or myocardial infarction who were candidates for PCI. In the coronary angiography, the culprit vessel involved was evaluated, and bolus nitroglycerin at a dose of 25–200 mcg was injected into the affected coronary artery. A significant change in the percentage of coronary artery stenosis was considered a positive response, and these patients were then compared with patients who did not have a substantial change in the percentage of stenosis at the same time. Univariate analysis and then multivariate logistic regression analysis was performed to determine the predictors of response to intracoronary nitroglycerin.

Results

Among 360 patients, 27 (7.5%) responded to nitroglycerine, and 333 (92.5%) were non-responsive. The mean age of patients was 60.2 ± 11.6 years, ranging from 23 to 93 years, and 265 (73.6%) were men. The study groups were not significantly different in the baseline demographic characteristics. The presence of multivessel disease (Odds ratio (OR) = 16.26, 95% confidence interval (CI):2.07–127.6; P = 0.008) and stenosis in the left circumflex artery (OR = 3.62, 95% CI: 1.03–12.70; P = 0.044) were the independent predictors for nonresponse to nitroglycerine, leading to PCI.

Conclusion

In some cases, especially those without multivessel diseases, intracoronary nitroglycerine administration can efficiently relieve coronary stenosis and prevent unnecessary PCI.

Advances in the Post-coronary Artery Bypass Graft Management of Occlusive Coronary Artery Disease

Revascularisation of chronic total occlusion (CTO) represents one of the most challenging aspects of percutaneous coronary intervention, but advances in equipment and an understanding of CTO revascularisation techniques have resulted in considerable improvements in success rates. In patients with prior coronary artery bypass grafting (CABG) surgery, additional challenges are encountered. This article specifically explores these challenges, as well as antegrade methods of CTO crossing. Techniques, equipment that can be used and reference texts are highlighted with the aim of providing potential CTO operators adequate information to tackle additional complexities likely to be encountered in this cohort of patients. This review forms part of a wider series where additional aspects of patients with prior CABG should be factored into decisions and methods of revascularisation.

Long-term vascular function in CTO recanalization: A randomized clinical trial of ticagrelor vs. clopidogrel

BACKGROUND

Coronary vascular function of a chronic coronary total occlusion (CTO) immediately after recanalization is known to be poor and to be partially improved by pre-treatment with loading dose of ticagrelor vs. clopidogrel. It is unknown if this vascular dysfunction is maintained at long-term follow-up and may be improved by 1-year dual antiplatelet therapy (DAPT).

METHODS

The TIGER is a prospective, open-label, two parallel-group controlled clinical trial, which 1:1 randomized 50 CTO patients to pre-PCI loading dose and subsequent 1-year DAPT with ticagrelor vs. clopidogrel. Coronary blood flow (CBF) under stepwise adenosine infusion was assessed after drug loading dose and at follow-up and compared between the two drug groups, adjusting for time of follow-up.

RESULTS

Out of 50 patients with index CBF evaluation, 38 (76%) patients underwent angiographic follow-up (23 and 15 at 1 and 3-year, respectively) and Doppler data was available in 35 (70%). A high CBF area under the curve (AUC), already observed after loading dose in ticagrelor vs. clopidogrel group (p = 0.027), was maintained at follow-up (AUC 34815.22 ± 24,206.06 vs. AUC 22712.47 ± 13,768.95; p = 0.071). Specifically, whereas high ticagrelor loading dose-related CBF was sustained at follow-up (p = 0.933), clopidogrel loading dose-related CBF increased at follow-up (p = 0.039).

CONCLUSION

The TIGER trial showed that DAPT with ticagrelor maintained a non-significantly higher CBF in a recanalized CTO as compared to clopidogrel, whose treated patients exhibit a lower CBF immediately after PCI with a significant increase at follow-up. The clinical value of such sustained high coronary flow should be evaluated in a larger group of patients.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02211066 (ClinicalTrials.gov number NCT02211066).

Long-Term Outcomes of Percutaneous Coronary Intervention for Patients With In-Stent Chronic Total Occlusion Versus De Novo Chronic Total Occlusion

Limited data are available on long-term outcomes and health status in the treatment of in-stent coronary chronic total occlusion (IS-CTO) and de novo coronary chronic total occlusion (de novo CTO). This study compared the long-term clinical outcomes and health status of percutaneous coronary intervention (PCI) for patients with IS-CTO versus patients with de novo CTO in the drug-eluting stent era. We screened 483 consecutive patients with 1 CTO lesion, including 81 patients with IS-CTO and 402 patients with de novo CTO. Propensity score matching was used to balance baseline characteristics between the 2 groups. The clinical end point was major adverse cardiac events (MACE). The success rates of CTO lesion revascularization were similar in both groups. In the propensity score-matched patients, after a median follow-up of 36 months, MACE was observed in 32.8% of patients with IS-CTO versus 13.5% of the patients with de novo CTO (P < .001), mainly driven by target-vessel revascularization (21.9% vs 6.7%; P < .01). Moreover, patients with IS-CTO had significantly worse Seattle Angina Questionnaire anginal stability scores than the patients with de novo CTO. In conclusion, patients with IS-CTO after PCI had a worse clinical outcome, mainly MACE, and a poorer anginal stability in the long term than patients with de novo CTO.

Fate of lumen size in distal coronary segment following successful chronic total occlusion recanalization

BACKGROUND

Restoration of anterograde blood flow leads to alterations in vascular wall stress that may influence lumen size distal to chronic total occlusion (CTO) lesions. We sought to assess changes in lumen diameter of segments distal to the stent segment of successfully recanalized CTO.

METHODS

We analyzed 507 consecutive CTO cases with stent implantation that underwent follow-up angiography at a single high-volume center (mean follow-up of 13.5 months). Segments ≤40 mm distal to the stent edge were analyzed using quantitative coronary angiography.

RESULTS

At follow-up, lumen diameters significantly increased; diameter changes of 0.26 ± 0.47 (percent diameter change of 18.2%) at 5 mm distal, mean lumen diameter changes of 0.23 ± 0.35 (14.3%) and minimal lumen diameter changes of 0.22 ± 0.80 (24.7%) (all p < 0.001). Lumen enlargement was similar between visually shrunken and stenosed vessels (degree of stenosis ≥20% with luminal irregularities) distal to stents; 5 mm distal (0.32 ± 0.48 vs. 0.30 ± 0.48, p = 0.76), mean lumen diameter changes (0.26 ± 0.37mm vs. 0.26±0.33 mm, p = 0.94), minimal lumen diameter changes (0.28 ± 0.43 mm vs. 0.22 ± 1.30 mm, p = 0.48). There was no association between degree of in-stent narrowing and changes in distal lumen diameter (Spearman r = -0.02, p = 0.59). Multivariate logistic regression for the predictors of greater lumen enlargement indicated that patients with left ventricle dysfunction (ejection fraction ≤45%) had greater enlargement [odds ratio (OR): 2.53, 95% confidence interval (CI): 1.23-5.23, p = 0.01]. Conversely, a low hematocrit (male <40%, and female <35%) was associated with attenuated lumen enlargement (OR: 0.68 95% CI: 0.47-0.98; p = 0.04).

CONCLUSIONS

Lumen diameter distal to CTO lesions significantly increased following successful revascularization, regardless of diseased status of the distal bed or degree of in-stent narrowing. These findings implicate appropriate determination of stent size, stent coverage length, as well as management strategies of distal vessels.

Impact of myocardial bridge on late lumen enlargement in distal reference segments after recanalization of coronary chronic total occlusion

Successful recanalization of coronary chronic total occlusion (CTO) can induce subsequent positive vascular remodeling. Although myocardial bridge (MB) is known to alter endothelial function and wall shear stress, the impact of MB on late lumen enlargement in the distal segment is unclear. A total of 59 patients who underwent successful percutaneous coronary intervention (PCI) for CTO in the left anterior descending artery (LAD) under intravascular ultrasound (IVUS) guidance and follow-up angiography at 8-12 months were included. Gray-scale IVUS images were analyzed and MB was detected. Lumen diameter (LD) at distal reference at post-PCI was quantitatively compared with corresponding LD at follow-up coronary angiography to assess late lumen enlargement. MB on IVUS was detected in 17 patients (29%). The length from LAD ostium to the entry of CTO was shorter (11.7 ± 13.9 vs. 22.8 ± 13.4 mm, p = 0.006) and LD at distal reference at post-PCI was smaller (1.65 ± 0.54 vs. 1.97 ± 0.56 mm, p = 0.049) in patients with MB than those without. At the mean follow-up of 10.4 ± 2.4 months, LD at distal reference was significantly increased by 25% from baseline to follow-up in the overall population (1.88 ± 0.57 vs. 2.21 ± 0.41 mm, p < 0.001), with a greater increase in patients with MB compared to those without (46 ± 31% vs. 17 ± 29%, p < 0.001). Multivariable analysis indicated MB as an independent predictor of late lumen enlargement. In patients with MB on IVUS, CTO was located in more proximal segment of LAD than those without. Late lumen enlargement at follow-up was greater in patients with MB compared to the counterpart.

Mechanisms and diagnostic evaluation of persistent or recurrent angina following percutaneous coronary revascularization

Persistence or recurrence of angina after a percutaneous coronary intervention (PCI) may affect about 20-40% of patients during short-medium-term follow-up. This appears to be true even when PCI is 'optimized' using physiology-guided approaches and drug-eluting stents. Importantly, persistent or recurrent angina post-PCI is associated with a significant economic burden. Healthcare costs may be almost two-fold higher among patients with persistent or recurrent angina post-PCI vs. those who become symptom-free. However, practice guideline recommendations regarding the management of patients with angina post-PCI are unclear. Gaps in evidence into the mechanisms of post-PCI angina are relevant, and more research seems warranted. The purpose of this document is to review potential mechanisms for the persistence or recurrence of angina post-PCI, propose a practical diagnostic algorithm, and summarize current knowledge gaps.

Coronary physiology before and after chronic total occlusion treatment: what does it tell us?

Studies performed in the last two decades demonstrate that after successful percutaneous coronary intervention (PCI) of a chronically occluded coronary artery, the physiology of the chronic total occlusion (CTO) vessel and dependent microvasculature does not normalise immediately but improves significantly over time. Generally, there is an increase in fractional flow reserve (FFR) in the CTO artery, a decrease in collateral blood supply and an increase in FFR in the donor artery accompanied by an increase in blood flow and decrease in microvascular resistance in the myocardium supplied by the CTO vessel. Analogous to these physiological changes, positive remodelling of the distal CTO artery also occurs over time, and intravascular imaging can be helpful for analysing distal vessel parameters. Follow-up coronary angiography with physiological measurements after several weeks to months can be helpful and informative in a subset of patients in order to decide upon the necessity for treatment of residual coronary artery stenosis in the vessel distal to the CTO or in the contralateral donor artery, as well as in deciding whether stent optimisation is indicated. We suggest that such physiological guidance of CTO procedures avoids unnecessary overtreatment during the initial procedure, guides interventions at follow-up, and improves our understanding of what PCI in CTO means.

Recovery of Absolute Coronary Blood Flow and Microvascular Resistance After Chronic Total Occlusion Percutaneous Coronary Intervention: An Exploratory Study

Background

This study aimed to investigate longitudinal physiological changes in the recanalized coronary chronic total occlusion (CTO) vessel and its dependent myocardium after successful percutaneous coronary intervention (PCI).

Methods and Results

In this pilot study, 25 patients scheduled for elective CTO PCI with viable myocardium and angiographically visible collaterals were included. Absolute coronary blood flow and absolute microvascular resistance were measured invasively using continuous thermodilution. Measurements were performed immediately after successful CTO PCI and at short‐term follow‐up. In a subgroup of patients, physiological measurements were performed at the predominant donor vessel before CTO PCI, immediately afterwards, and at follow‐up. Absolute coronary blood flow in the recanalized CTO artery increased from 148±53 mL/min immediately after PCI to 221±77 mL/min at follow‐up (P<0.001). In agreement, absolute resistance in the myocardial territory perfused by the CTO artery, decreased from 545±255 Wood units immediately after the procedure to 387±128 Wood units at follow‐up (P=0.014). There were no significant changes in the absolute coronary blood flow and resistance in the predominant donor between baseline and follow‐up. Positive remodeling of the distal CTO vessel with an increase in lumen diameter was observed.

Conclusions

After successful CTO PCI, blood flow in the recanalized artery and microvascular function of the dependent myocardium are not immediately normal but recover over time.

A comparison of procedural success rate and long-term clinical outcomes between in-stent restenosis chronic total occlusion and de novo chronic total occlusion using multicenter registry data

Background

There have been little data about outcomes of percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) chronic total occlusion (CTO) in the drug eluting stent (DES) era. This study aimed to compare the procedural success rate and long-term clinical outcomes of ISR CTO and de novo CTO.

Methods and results

Patients who underwent PCI for ISR CTO (n = 164) versus de novo CTO (n = 1208) were enrolled from three centers in Korea between January 2008 and December 2014. Among a total of ISR CTO, a proportion of DES ISR CTO was 79.3% (n = 130). The primary outcome was major adverse cardiac events (MACEs); a composite of all-cause death, non-fatal myocardial infarction (MI), or target lesion revascularization (TLR). Following propensity score-matching (1:3), the ISR CTO group (n = 156) had a higher success rate (84.6% vs. 76.0%, p = 0.035), mainly driven by high success rate of PCI for DES ISR CTO (88.6%), but showed a higher incidence of MACEs [hazard ratio (HR): 2.06; 95% confidence interval (CI) 1.37–3.09; p < 0.001], mainly driven by higher prevalence of MI [HR: 9.71; 95% CI 2.06–45.81; p = 0.004] and TLR [HR: 3.04; 95% CI 1.59–5.81; p = 0.001], during 5 years of follow-up after successful revascularization, as compared to the de novo CTO group (n = 408).

Conclusion

The procedural success rate was higher in the ISR CTO than the de novo CTO, especially in DES ISR CTO. However, irrespective of successful revascularization, the long-term clinical outcomes for the ISR CTO were significantly worse than those for the de novo CTO, in terms of MI and TLR.

Graphic abstract

Guiding Principles for Chronic Total Occlusion Percutaneous Coronary Intervention

Outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have improved because of advancements in equipment and techniques. With global collaboration and knowledge sharing, we have identified 7 common principles that are widely accepted as best practices for CTO-PCI.  1. Ischemic symptom improvement is the primary indication for CTO-PCI.  2. Dual coronary angiography and in-depth and structured review of the angiogram (and, if available, coronary computed tomography angiography) are key for planning and safely performing CTO-PCI.  3. Use of a microcatheter is essential for optimal guidewire manipulation and exchanges.  4. Antegrade wiring, antegrade dissection and reentry, and the retrograde approach are all complementary and necessary crossing strategies. Antegrade wiring is the most common initial technique, whereas retrograde and antegrade dissection and reentry are often required for more complex CTOs.  5. If the initially selected crossing strategy fails, efficient change to an alternative crossing technique increases the likelihood of eventual PCI success, shortens procedure time, and lowers radiation and contrast use.  6. Specific CTO-PCI expertise and volume and the availability of specialized equipment will increase the likelihood of crossing success and facilitate prevention and management of complications, such as perforation.  7. Meticulous attention to lesion preparation and stenting technique, often requiring intracoronary imaging, is required to ensure optimum stent expansion and minimize the risk of short- and long-term adverse events. These principles have been widely adopted by experienced CTO-PCI operators and centers currently achieving high success and acceptable complication rates. Outcomes are less optimal at less experienced centers, highlighting the need for broader adoption of the aforementioned 7 guiding principles along with the development of additional simple and safe CTO crossing and revascularization strategies through ongoing research, education, and training.

Coronary chronic total occlusion intervention: A pathophysiological perspective

Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) is the last frontier in coronary intervention. PCI of CTO carries multiple advantages, such as significant improvement in symptoms, improvement in abnormal wall motion and left ventricular function and, possibly, increased long-term survival. As of today the procedural success is markedly improved because of technical innovations and is limited to highly experienced operators. To enhance the overall success rate from a worldwide perspective, a thorough understanding of its pathophysiology is critical to further development of newer techniques and technologies. In this review, the author outlines in-depth the evidence that underpins our understanding of CTO pathophysiology and its insight into CTO intervention that incorporates various steps and techniques to cross the lesion.

Pattern of vascular remodeling of distal reference segment after recanalization of chronic total occlusion, long-term angiographic follow-up

Chronic total occlusion (CTO) is probably caused by thrombus and lipid-rich cholesterol esters that are replaced over time by collagen and calcium deposition. Experimental models showed endothelial cell necrosis in response to vessel ligation, whereas more recent models suggest that the endothelium might retain viability guiding the subsequent development of CTO, including CTO neo-revascularization, which occurs within the lumen and in various layers of the vessel wall, by the release of paracrine substances. It is uncertain whether after CTO recanalization the recovery of anterograde reverses endothelial dysfunction, thus promoting vasodilation and positive remodeling.

Full stent expansion of chronic total occlusion lesions requires prolonged inflation

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has been associated in some studies with higher target vessel revascularization (TVR) rates than non-CTO PCI. Optimal stent inflation time and its effect on TVR in CTO PCI is unknown. We investigated the time required for stent deployment using the previously described pressure optimized protocol (POP), which uses stent balloon pressure stability rather than an arbitrary inflation time as an end point for balloon deflation. We also compared TVR with CTO PCI vs non-CTO using the POP protocol in both groups.

METHODS

Patients with successful CTO PCI using POP between 2012 and 2015 were included. Patients having non-CTO PCI using POP and matched for stent diameter and length and temporal proximity constituted the control group to compare inflation time (n=83 each). TVR at 1year was compared between PCI during the time period using POP (CTO=83, non-CTO=263).

RESULTS

Stent inflation time to achieve optimal stent inflation using POP was longer in CTO vs non-CTO lesions (136±60 vs 108±51s, p=0.001). TVR at 365days was similar in CTO and non-CTO cohorts (2.4% vs 2.6%, p=0.9).

CONCLUSION

Stent expansion using POP in CTO lesions requires longer inflation duration but leads to similar TVR rates at 1year in CTO PCI compared with non-CTO PCI.

Utility of Intravascular Ultrasound in Percutaneous Revascularization of Chronic Total Occlusions: An Overview

Intravascular ultrasound has been used for >20 years to guide percutaneous coronary intervention in different subsets of coronary lesions. During the last decade, the interest in percutaneous coronary intervention for chronic total occlusion (CTO) has increased dramatically, leading to high success rates. Failure of guidewire crossing is the most common reason for failed CTO attempts. Certain angiographic features, such as blunt proximal CTO cap, tortuosity, heavy calcification, and lack of visibility of path in the distal vessel, increase procedural difficulty. A better understanding of the behavior of the guidewire within the CTO segment may represent a key issue to achieve successful outcome. In this respect, intravascular ultrasound imaging might have potential roles in the recanalization of CTOs. In this paper, we focused on the usefulness and the applications of intravascular ultrasound imaging in percutaneous CTO recanalization, underlying its impact on clinical outcome.

Everolimus-eluting bioresorbable vascular scaffolds for treatment of complex chronic total occlusions

AIMS

Bioresorbable vascular scaffolds (BVS) represent a novel therapeutic option for the treatment of coronary artery diseases. The objective of this study was to evaluate the feasibility of BVS implantation in complex chronic total occlusions (CTO).

METHODS AND RESULTS

The present report is a multicentre registry evaluating results after BVS deployment in challenging CTO lesions, defined as J-CTO score ≥2 (difficult or very difficult). A total of 105 patients were included in the present analysis. The mean J-CTO score was 2.61 (difficult 52.4%, very difficult 47.6%). Device success and procedural success rates were 98.1% and 97.1%, respectively. The retrograde approach was used in 25.7% of cases. After wire crossing, predilatation was performed in all cases with a mean predilatation balloon diameter of 2.73±0.43 mm. The mean scaffold length was 59.75±25.85 mm, with post-dilatation performed in 89.5% of the cases and a mean post-dilatation balloon diameter of 3.35±0.44 mm. Post-PCI minimal lumen diameter was 2.50±0.51 mm and percentage diameter stenosis 14.53±10.31%. At six-month follow-up, a total of three events were reported: one periprocedural myocardial infarction, one late scaffold thrombosis and one additional target lesion revascularisation.

CONCLUSIONS

The present report suggests the feasibility of BVS implantation in complex CTO lesions, given adequate lesion preparation and post-dilatation, with good acute angiographic results and midterm clinical outcomes.

Rationale and design of the SYNTAX II trial evaluating the short to long-term outcomes of state-of-the-art percutaneous coronary revascularisation in patients with de novo three-vessel disease

AIMS

The applicability of the results of the SYNTAX trial comparing percutaneous coronary intervention (PCI) using first-generation drug-eluting stents (DES) with coronary artery bypass graft (CABG) surgery for the treatment of patients with complex coronary artery disease (CAD) has been challenged by recent major technical and procedural developments in coronary revascularisation. Functional assessment of coronary lesions has contributed to marked improvements in both safety and efficacy of DES implantation. In addition, the recent development of the SYNTAX score II, a clinical tool based on anatomical and clinical factors, allows individualised objective decision making regarding the optimal revascularisation modality in patients with complex CAD. The ongoing SYNTAX II trial is currently evaluating the effectiveness of the clinical and technological advances in the treatment of patients with complex (de novo three-vessel) CAD.

METHODS AND RESULTS

The SYNTAX II trial is a multicentre, all-comers, open-label, single-arm trial aiming to recruit 450 patients with de novo three-vessel CAD in approximately 25 European interventional cardiology centres. All patients will be selected and treated following the SYNTAX II strategy, which includes: a) establishing the appropriateness of revascularisation utilising the SYNTAX score II as a clinical tool to allow objective decision making by the Heart Team, b) ischaemia-driven revascularisation based on functional intracoronary assessment, c) implantation of the new-generation everolimus-eluting platinum chromium coronary stent with thin struts and abluminal bioabsorbable polymer coating to promote rapid vessel healing, d) intravascular ultrasound-guided DES implantation, and e) treatment at centres with expertise in CTO recanalisation. The primary endpoint is a composite of the major adverse cardiac and cerebral events (MACCE) rate at one-year follow-up compared to the historical PCI arm of the SYNTAX trial. An exploratory endpoint will be MACCE at five-year follow-up compared to the historical surgical arm of the SYNTAX trial.

CONCLUSIONS

The SYNTAX II trial will provide valuable information on outcomes of state-of-the-art PCI for the contemporary management of complex (de novo three-vessel) CAD. SYNTAX II will be of critical value in the design of future trials in this arena.

Usefulness and Safety of a Novel Modification of the Retrograde Approach for the Long Tortuous Chronic Total Occlusion of Coronary Arteries

The aim of this study was to evaluate the feasibility and efficacy of the Guidezilla guide extension catheter in a reverse controlled antegrade and retrograde subintimal tracking (CART) technique for chronic total occlusion (CTO) recanalization.We retrospectively collected 80 CTO cases using reverse CART technology from January 2015 to October 2015 and 20 CTO cases using Guidezilla reverse-CART technology from October 2015 to March 2016. Guidezilla was applied in cases when it was difficult to advance a retro-guidewire through an occlusion segment into the antegrade guide catheter.The Guidezilla group had more cases with an occlusion longer > 20 mm (100.0% versus 72.5%, P = 0.005) and "bending > 45°" (90.0% versus 63.7%, P = 0.029) than the non-Guidezilla group, while the non-Guidezilla group had more retry lesions (25.0% versus 63.8%, P = 0.002). The septal collateral channel was the preferred choice for retro-recanalization in both groups (90.0% in Guidezilla group and 68.8% in non-Guidezilla group). All cases in the Guidezilla group achieved technical success with a TIMI 3 flow in the distal true lumen (100.0% versus 75.0% in non-Guidezilla group, P = 0.010). Cardiac tamponade and perforation in the epicardial artery was observed in 1 case each in the Guidezilla group. In the non-Guidezilla group, 19 complications occurred during the PCI procedure. No target vessel revascularization or in-hospital death occurred in either group.CTO lesions using the Guidezilla guide extension catheter to facilitate entry to an antegrade catheter in reverse CART technology is convenient and safe with a high success rate.

One-year outcomes after successful chronic total occlusion percutaneous coronary intervention: The impact of dissection re-entry techniques

We aimed to determine clinical outcomes 1 year after successful chronic total occlusion (CTO) PCI and, in particular, whether use of dissection and re-entry strategies affects clinical outcomes. Hybrid approaches have increased the procedural success of CTO percutaneous coronary intervention (PCI) but longer-term outcomes are unknown, particularly in relation to dissection and re-entry techniques. Data were collected for consecutive CTO PCIs performed by hybrid-trained operators from 7 United Kingdom (UK) centres between 2012 and 2014. The primary endpoint (death, myocardial infarction, unplanned target vessel revascularization) was measured at 12 months along with angina status. One-year follow up data were available for 96% of successful cases (n = 805). In total, 85% of patients had a CCS angina class of 2-4 prior to CTO PCI. Final successful procedural strategy was antegrade wire escalation 48%; antegrade dissection and re-entry (ADR) 21%; retrograde wire escalation 5%; retrograde dissection and re-entry (RDR) 26%. Overall, 47% of CTOs were recanalized using dissection and re-entry strategies. During a mean follow up of 11.5 ± 3.8 months, the primary endpoint occurred in 8.6% (n = 69) of patients (10.3% (n = 39/375) in DART group and 7.0% (n = 30/430) in wire-based cases). The majority of patients (88%) had no or minimal angina (CCS class 0 or 1). ADR and RDR were used more frequently in more complex cases with greater disease burden, however, the only independent predictor of the primary endpoint was lesion length. CTO PCI in complex lesions using the hybrid approach is safe, effective and has a low one-year adverse event rate. The method used to recanalize arteries was not associated with adverse outcomes. © 2017 Wiley Periodicals, Inc.

Clinical Utility of the Japan-Chronic Total Occlusion Score in Coronary Chronic Total Occlusion Interventions: Results from a Multicenter Registry

BACKGROUND

The performance of the Japan-chronic total occlusion (J-CTO) score in predicting success and efficiency of CTO percutaneous coronary intervention has received limited study.

METHODS AND RESULTS

We examined the records of 650 consecutive patients who underwent CTO percutaneous coronary intervention between 2011 and 2014 at 6 experienced centers in the United States. Six hundred and fifty-seven lesions were classified as easy (J-CTO=0), intermediate (J-CTO=1), difficult (J-CTO=2), and very difficult (J-CTO≥3). The impact of the J-CTO score on technical success and procedure time was evaluated with univariable logistic and linear regression, respectively. The performance of the logistic regression model was assessed with the Hosmer-Lemeshow statistic and receiver operator characteristic curves. Antegrade wiring techniques were used more frequently in easy lesions (97%) than very difficult lesions (58%), whereas the retrograde approach became more frequent with increased lesion difficulty (41% for very difficult lesions versus 13% for easy lesions). The logistic regression model for technical success demonstrated satisfactory calibration and discrimination (P for Hosmer-Lemeshow =0.743 and area under curve =0.705). The J-CTO score was associated with a 2-fold increase in the odds of technical failure (odds ratio 2.04, 95% confidence interval 1.52-2.80, P<0.001). Procedure time increased by ≈20 minutes for every 1-point increase of the J-CTO score (regression coefficient 22.33, 95% confidence interval 17.45-27.22, P<0.001).

CONCLUSIONS

J-CTO score was strongly associated with final success and efficiency in this study, supporting its expanded use in CTO interventions.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02061436.

Serial Intravascular Ultrasound Findings After Treatment of Chronic Total Occlusions Using Drug-Eluting Stents

Morphologic changes after chronic total occlusion (CTO) treatment with drug-eluting stents (DESs) have not been assessed in detail. Our aim was to use both baseline and follow-up intravascular ultrasound studies to evaluate the morphologic changes and, especially, the changes in distal vessel size and the effect of subintimal stenting after treatment of CTOs with DES. We analyzed serial follow-up intravascular ultrasound (baseline and follow-up at 9 ± 2 months) after DES implantation into 40 CTOs. Overall, 33 CTOs were treated by the anterograde approach; and 7 were treated by the retrograde approach. Minimum lumen cross-sectional area (CSA) trended toward a decrease from baseline to follow-up (4.8 ± 1.7 vs 4.5 ± 1.7 mm(2), p = 0.10), although the minimum stent CSA (4.8 ± 1.7 vs 4.9 ± 1.7 mm(2), p = 0.26) did not change. The distal reference, but not the proximal reference lumen CSA, increased significantly at follow-up (3.8 ± 2.0 to 5.1 ± 2.3 mm(2), p = 0.0004). Late-acquired stent malapposition was seen in 17 patients (42.5%). In 8 CTOs (20%), a part of the stent was implanted into a subintimal space; in these 8 patients, maximum percent neointimal hyperplasia and minimum lumen area was similar in the subintimal segment compared with the adjacent intraplaque segment. The frequency of late-acquired stent malapposition was similar. In conclusion, after CTO treatment with DES, distal vessel enlargement was detected. Subintimal stenting after recanalization of CTO was not inferior compared with stenting within the plaque in terms of long-term morphologic impact.

Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization

OBJECTIVES

The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient

BACKGROUND

Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading.

METHODS

After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels.

RESULTS

After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference -1.36 mm Hg/cm/s (-2.33 to -0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference -0.20 (-0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002).

CONCLUSIONS

BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance. © 2016 Wiley Periodicals, Inc.

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.