Coronary Chronic Occlusion Research Articles

Endovascular myocardial revascularization in patients with multivessel coronary artery disease with chronic total occlusion and high surgical risk

The main reason for incomplete myocardial revascularization is the presence of chronic coronary total occlusion (CTO), which is detected in every fourth patient during coronary angiography. At the same time, a generally accepted approach to the treatment of CTO has not yet been developed.Aim. To assess the rationale of complete myocardial revascularization in patients with multivessel coronary artery disease (CAD) with chronic total occlusion and high surgical risk.Material and methods. This retrospective, open-label, non-randomized clinical trial was carried out included 180 patients multivessel CAD and CTO. The patients underwent endovascular surgery for complete myocardial revascularization. Depending on the success of surgery, the patients were divided into groups of complete and incomplete myocardial revascularization. Endpoints were death, acute coronary syndrome, re-revascularization after 1-year follow-up. Left ventricular (LV) contractility and clinical status of patients in the study groups after 1 year of observation was assessed.Results. The median follow-up was 12,1 months. The successful rate of revascularization was 79,4%. The incidence of main composite endpoint in the group of complete myocardial revascularization was 5,59%, while in the group of incomplete revascularizations — 21,6% (p=0,005).Conclusion. The study showed that low incidence of intraoperative complications and a high successful rate of revascularization are characteristic of complete myocardial revascularization in patients at high surgical risk with multivessel CAD and CTO. Complete myocardial revascularization leads to a significant decrease in the incidence of major coronary events.

Abstract 16567: 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) with ticagrelor vs. clopidogrel. 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). A higher 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±24206.06 vs. AUC 22712.47±13768.95; 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 may maintain a higher CBF in a recanalized CTO as compared to clopidogrel, whose treated patients exhibit a lower CBF immediately after PCI with slight increase at follow-up. The clinical value of such sustained higher coronary flow should be evaluated in a larger group of patients.

Japanese multicenter registry evaluating the antegrade dissection reentry with cardiac computed tomography for chronic coronary total occlusion

Abstract Objective This study was performed to evaluate the efficacy of cardiac computed tomography (CT) for antegrade dissection re-entry (ADR) technique in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Background Although PCI of CTO is a rapidly evolving field, procedure success rate remains suboptimal. Recently, ADR with Stingray device for CTO-PCI has also evolved to one of the pillar technique of the hybrid algorithm. Although the success rate of the device could be improved, it also remains not always high especially as first crossing strategy. Methods Forty eight patients with total occlusion suitable for revascularization evaluated by baseline coronary angiography and cardiac CT were enrolled in this study from April 2017 to April 2019 from 30 enrolled centers. The primary observation was procedural success. Furthermore, all puncture point with Stingray were analyzed by cardiac CT. In each point, 1) plaques on the isolated myocardial side at distal puncture site (+1 point), 2) any plaques excluded above definition at distal puncture site (+2 points), 3) calcification on both 1 and 2 at distal puncture site (+1 point) were analyzed and calculated the score (Score 0–3) (Figure 1). Results Overall procedure success rate was 95.8% (46/48) and antegrade success rate was 91.3% (42/46). Sixteen cases were succeeded with single guidewire escalation and 32 cases were attempted ADR with Stingray system. Within them, 25 cases were succeeded and 7 cases were observed puncture failure. And 3cases were succeeded with IVUS guide and 2 cases were with retrograde appTechnical success rate with stingray was 78.1% (25/32). Cardiac CT was analyzed 60 puncture sites in 32 cases which were attempted ADR with stingray system (1.88 sites/case). CT score at ADR success point was significantly smaller compare to that at ADR failure point (0.68±1.09 vs 1.77±1.09, p<0.0001). Conclusions Pre procedure Cardiac CT and CT score might be useful for ADR technique in CTO PCI not only for case selection but also for puncture site selection. Figure 1 Funding Acknowledgement Type of funding source: None

Viability and functional recovery after chronic total occlusion percutaneous coronary intervention

Abstract Background Current guidelines advocate viability assessment to guide percutaneous coronary intervention (PCI) of chronic coronary total occlusions (CTO). Purpose Aim of the present study was to evaluate viability as well as global and regional functional recovery after successful CTO PCI using quantitative cardiac magnetic resonance (CMR) imaging. Methods 132 patients with sequential CMR at baseline and 3-months after successful CTO PCI were prospectively recruited between 2013 and 2018. Segmental wall thickening (SWT) and percentage late gadolinium enhancement (LGE) were quantitatively measured per segment. Viability was defined as dysfunctional myocardium (<2.84mm SWT) with no or limited scar (≤50% LGE). Results Significant improvements in left ventricular (LV) ejection fraction (from 48.1±11.8 to 49.5±12.1%, p<0.01), LV end-diastolic volume (from 99.1±31.8 to 95.7±30.2ml, p<0.01), and LV end-systolic volume (from 54.4±30.5 to 51.2±29.3ml, p<0.01) were observed after CTO PCI. CTO segments with viability (N=216, (31%)) demonstrated a significantly higher increase in SWT (0.80±1.39mm) compared to CTO segments with pre-procedural preserved function (N=456 (65%), 0.07±1.43mm, p<0.01) or extensive scar (LGE >50%, N=26 (4%), −0.08±1.09mm, p<0.01). Improvement in SWT was comparable between segments with viability if further stratified to 0, >0–25, and >25–50% hyperenhancement (p=0.94). Patients with ≥2 CTO segments viability showed more SWT increase in the CTO territory compared to patients with 0–1 segment viability (0.49±0.93 vs. 0.12±0.98mm, p=0.03). Conclusions Improvements in LV function and volumes were significant but modest following CTO PCI. Detection of dysfunctional myocardial segments without extensive scar (≤50% LGE) as a marker for viability may aid in identifying subjects with significant regional functional recovery after CTO PCI. Funding Acknowledgement Type of funding source: None

Prediction-Determining Outcomes and Their Predictors in Atrial Fibrillation Patients Receiving Multicomponent Antithrombotic Therapy in Real Clinical Practice.

Aim Searching for clinical, angiographic, and biochemical predictors of cardiovascular complications (CVC) and hemorrhagic complications in patients with atrial fibrillation (AF) receiving a multicomponent antithrombotic therapy (MAT) for an elective percutaneous coronary intervention (PCI). Patients with ischemic heart disease (IHD) and AF who require MAT for PCI are at a high risk of thrombotic complications (stroke, systemic embolism, coronary events) and hemorrhage. This warrants searching for new risk factors determining prediction of the outcome.Materials and methods This study included 207 patients (146 males aged 70.1±8.3 years) with IHD and AF who received direct oral anticoagulants (DOAC) as a part of their MAT therapy. Median duration of the follow-up was 12 [8.0; 12.0] months. The efficacy endpoint was a sum of CVCs combining cardiovascular death, ischemic stroke, venous thromboembolic complications, acute coronary syndrome (ACS), and requirement for an unscheduled PCI. "Coronary events", including ACS and requirement for an unscheduled PCI were analyzed separately. The safety endpoint was BARC type 2-5 bleeding. Upon admission, biomarkers (growth-differentiation factor 15 (GDF-15), D-dimer, thrombin-activated fibrinolysis inhibitor (TAFI), and plasminogen activator inhibitor-1 (PAI-1)) were measured for all patients. Searching for prognostically significant indexes was performed with the Cox proportional hazards regression.Results Incidence of all CVCs was 16.4 %. Independent predictors of CVC included the DOAC treatment at a reduced dose (odds ratio (OR) 2.5 at 95 % confidence interval (CI) 1.02-6.15; p=0.0454), GDF-15 >1191 pg /ml (OR 3.76 at 95 % CI, 1.26-11.18; p=0.0172), PAI-1 >13.2 U/ml (OR 2.67 at 95 % CI, 1.13-6,26; p=0.0245). Incidence of coronary complications was 9.2 %. Independent predictors of coronary complications included a SYNTAX index >26.5 (OR 4.5 at 95 % CI, 1.45-13.60; p=0.0090), PCI for chronic coronary occlusion (OR 3.21 at 95 % CI, 1.10-9.33; p=0.0326), a GDF-15 >1191 pg/ml (ОR 4.70 at 95 % CI, 1.32-16.81; p=0.0172). Incidence of BARC type 2-5 bleeding was 26.1 %. The only independent predictor for hemorrhage complications was the total PRECISE-DAPT score >30 (ОR 3.22; 95 % CI, 1.89-5.51; р<0.0001).Conclusion Three independent predictors of CVC were identified for patients with IHD and AF treated with MAT following an elective PCI: treatment with a reduced dose of DOAC, GDF-15 >1191 pg /ml, and PAI-1>13.2 U/ml. Independent predictors of coronary complications included a SYNTAX index >26.5, PCI for chronic coronary occlusion, and GDF-15 >1191 pg/ml. The factor associated with a risk of bleeding was the total PRECISE-DAPT score >30.

Examining the Relevance of Chronic Coronary Occlusion in Patients Undergoing TAVR

Examining the Relevance of Chronic Coronary Occlusion in Patients Undergoing TAVR

Ischaemic burden and changes in absolute myocardial perfusion after chronic total occlusion percutaneous coronary intervention.

The aim of this study was to explore the relationships between ischaemic burden and changes in absolute myocardial perfusion following chronic coronary total occlusion (CTO) percutaneous coronary intervention (PCI). A total of 193 consecutive patients underwent [15O]H2O positron emission tomography prior to and three months after successful CTO PCI. Change in perfusion defect size, quantitative hyperaemic myocardial blood flow (MBF) and coronary flow reserve (CFR) within the CTO area were compared among patients with limited (0-1 segment, N=15), moderate (2-3 segments, N=61) and large (≥4 segments, N=117) perfusion defects. Median reductions in defect size were 1 [0-1], 2 [1-3], and 4 [2-5] segments in patients with a limited, moderate and large defect (all comparisons p<0.01). Hyperaemic MBF and CFR improved significantly regardless of baseline defect size (overall between groups p=0.45 and p=0.55). After stratification of patients to a low, intermediate or high tertile according to baseline hyperaemic MBF or CFR levels, changes in hyperaemic MBF and CFR after CTO PCI were comparable between tertiles (overall p=0.75 and p=0.79). Major reductions in ischaemic burden can be achieved following CTO PCI, with more defect size reduction in patients with a larger perfusion defect, whereas hyperaemic MBF and CFR improve significantly irrespective of their baseline values or perfusion defect size.

Coronary computed tomography angiography and [15O]H2O positron emission tomography perfusion imaging for the assessment of coronary artery disease.

Determining the anatomic severity and extent of coronary artery disease (CAD) by means of coronary computed tomography angiography (CCTA) and its effect on perfusion using myocardial perfusion imaging (MPI) form the pillars of the non-invasive imaging assessment of CAD. This review will 1) focus on CCTA and [15O]H2O positron emission tomography MPI as stand-alone imaging modalities and their combined use for detecting CAD, 2) highlight some of the lessons learned from the PACIFIC trial (Comparison of Coronary CT Angiography, SPECT, PET, and Hybrid Imaging for Diagnosis of Ischemic Heart Disease Determined by Fractional Flow Reserve (FFR) (NCT01521468)), and 3) discuss the use of [15O]H2O PET MPI in the clinical work-up of patients with a chronic coronary total occlusion (CTO).

Coronary collaterals and myocardial viability in patients with chronic total occlusions.

This study aimed to evaluate associations between coronary collaterals and myocardial viability as assessed by quantitative cardiac magnetic resonance (CMR) imaging in patients with a chronic coronary total occlusion (CTO). A total of 218 patients with a CTO who underwent CMR between 2013 and 2018 were included. A concomitant collateral connection (CC) score 2 and Rentrop grade 3 defined well-developed collaterals in 146 (67%) patients, whereas lower CC scores or Rentrop grades characterised poorly developed collaterals. Dysfunctional myocardium (<3 mm segmental wall thickening [SWT]) and ≤50% late gadolinium enhancement (LGE) defined viability. Extensive scar (LGE >50%) was observed in only 5% of CTO segments. In the CTO territory, SWT was greater (3.72±1.51 vs 3.05±1.60 mm, p<0.01) and the extent of scar was less (7.0 [0.1-16.7] vs 13.1% [2.8-22.2], p=0.048) in patients having well-developed versus poorly developed collaterals. Viability was more prevalent in CTO segments among patients with poorly developed versus well-developed collaterals (44% vs 30% of segments, p<0.01), predominantly due to a higher prevalence of dysfunctional myocardium (51% vs 34% of segments, p<0.01) in the poorly developed collateral group. The infarcted area in myocardium subtended by a CTO is generally limited. Well-developed collaterals are associated with less myocardial scar and enhanced preserved function. However, viability was regularly present in patients with poorly developed collaterals.

Current algorithms for the treatment of chronic coronary total occlusions

Chronic coronary total occlusions (CTOs) represent the most complex group of lesions in interventional cardiology, and technical success in their treatment depends on not only the characteristics of the lesions themselves but also the experience of the operator.Over the past few years, many CTO recanalisation techniques have been proposed, leading to the need for standardisation to achieve a higher success rate. As a result, a number of algorithms that allow the surgeon to choose one or another recanalisation technique depending on the angiographic features of the vessel have been proposed.This article provides an overview of the main algorithms for choosing a CTO recanalisation strategy and considers the clinical and angiographic characteristics that form the basis of the algorithms. The possibility of their use in clinical practice has also been evaluated.Received 7 April 2020. Revised 27 April 2020. Accepted 27 April 2020.Funding: The study did not have sponsorship.Conflict of interest: Authors declare no conflict of interest.Author contributionsConception and design: O.V. Krestyaninov, D.A. KhelimskiiDrafting the article: O.V. Krestyaninov, D.A. Khelimskii, A.G. Badoian, R.A. Naydenov, R.U. IbragimovCritical revision of the article: R.A. Naydenov, R.U. IbragimovFinal approval of the version to be published: O.V. Krestyaninov, D.A. Khelimskii, A.G. Badoian, R.A. Naydenov, R.U. Ibragimov

The Relationship of HSP-70 with Calcineurin, Sod and Catalase Post-Acute Myocardial Infarction in Wistar Rats Model

Background: HSP-70s help to reduce infarct area through unclear mechanism. It appears that HSP-70 activates calcineurin and induce antioxidant enzymes such as Superoxide Dismutase (SOD) and catalase. Therefore, we sought to investigate the relationship of HSP-70 with calcineurin, SOD and catalase post-Acute Myocardial Infarction (AMI). Methods: An experimental study involved 24 Wistar rats as models of chronic coronary occlusion. The rats were randomly divided into 4 groups: no-intervention after AMI (N), sedentary intervention after AMI (S), exercise intervention after AMI (E), and sham (C). Intervention consisted of 2 weeks of recovery then 4 weeks of sedentary for group S or exercise for group E. HSP-70, calcineurin, SOD, and catalase expression in heart were evaluated the difference among groups. Correlation between HSP-70 to other proteins was analysed also. Results: HSP-70 and calcineurin was higher in group S and E compared to group N and C. HSP-70 (MD=0.97, 95% CI 0.60 to 1.34), calcineurin (MD=1.25, 95% CI 0.68 to 1.82, p<0.05), catalase (MD=0.57, 95% CI 0.25 to 0.88, p<0.05), and SOD (0.42, 95% CI 0.14 to 0.69, p<0.05) significantly higher in Group E compared to S. Sham group had higher SOD and catalase activity than group E. HSP-70 was correlated with calcineurin (r=0.856, p<0.05). HSP-70 was correlated with catalase and SOD when the analysis included only groups who had intervention. Conclusion: HSP-70 correlated with calcineurin and stimulated an increase in calcineurin activity.

Correlation of angiographic scoring system with percutaneous revascularization success in chronic coronary total occlusion patients

Correlation of angiographic scoring system with percutaneous revascularization success in chronic coronary total occlusion patients

Coexistence and outcome of coronary artery disease in Takotsubo syndrome.

Takotsubo syndrome (TTS) is an acute heart failure syndrome, which shares many features with acute coronary syndrome (ACS). Although TTS was initially described with angiographically normal coronary arteries, smaller studies recently indicated a potential coexistence of coronary artery disease (CAD) in TTS patients. This study aimed to determine the coexistence, features, and prognostic role of CAD in a large cohort of patients with TTS. Coronary anatomy and CAD were studied in patients diagnosed with TTS. Inclusion criteria were compliance with the International Takotsubo Diagnostic Criteria for TTS, and availability of original coronary angiographies with ventriculography performed during the acute phase. Exclusion criteria were missing views, poor quality of angiography loops, and angiography without ventriculography. A total of 1016 TTS patients were studied. Of those, 23.0% had obstructive CAD, 41.2% had non-obstructive CAD, and 35.7% had angiographically normal coronary arteries. A total of 47 patients (4.6%) underwent percutaneous coronary intervention, and 3 patients had acute and 8 had chronic coronary artery occlusion concomitant with TTS, respectively. The presence of CAD was associated with increased incidence of shock, ventilation, and death from any cause. After adjusting for confounders, the presence of obstructive CAD was associated with mortality at 30 days. Takotsubo syndrome patients with obstructive CAD were at comparable risk for shock and death and nearly at twice the risk for ventilation compared to an age- and sex-matched ACS cohort. Coronary artery disease frequently coexists in TTS patients, presents with the whole spectrum of coronary pathology including acute coronary occlusion, and is associated with adverse outcome. ClinicalTrials.gov number: NCT01947621.

Management of coronary perforations during angioplasty

Coronary perforation represents a terrible complication of percutaneous coronary intervention (PCI) which, if not promptly recognized and treated, can lead to catastrophic consequences for the patient. Hence, acquisition of the basic techniques for the treatment of coronary perforations is critical for the interventional cardiologist in order to safely perform PCIs. Although the incidence of coronary perforations remains low during PCI, it is possible to recognize some subgroups of patients and some types of coronary lesions, such as chronic coronary total occlusions, that are associated with increased risk. The treatments currently available depend on the type and site of coronary perforation, therefore timely recognition is of paramount importance in order to be able to quickly establish the most appropriate treatment.

Exercise Training Restores K+ Channel Contributions to Hydrogen Peroxide‐Mediated Dilation Independent of PKG Dimerization in Collateral‐Dependent Coronary Arterioles

In coronary artery disease (CAD), the ability of the coronary circulation to deliver blood to meet oxygen demands of the heart is often impaired. Exercise training has been established to mitigate the negative effects of CAD by preserving reactivity of the coronary microcirculation. We have previously reported that exercise increases the contribution of hydrogen peroxide (H2O2) to enhanced endothelium‐dependent vasodilation in collateral‐dependent coronary arterioles. Others have shown that cGMP‐dependent protein kinase (PKG) can be activated via oxidation by H2O2, inducing dimer formation. The PKG dimer has been shown to act on substrates, such as K+ channels, to contribute to vascular smooth muscle relaxation and vasodilation. In the current study, we tested the hypothesis that exercise training‐enhanced H2O2‐induced vasodilation is mediated through enhanced PKG dimerization and subsequent activation of Kv and BKca channels in coronary arterioles isolated from ischemic myocardium. An ameroid occluder was surgically placed on the proximal left circumflex coronary artery of female Yucatan miniature swine to induce gradual occlusion while the left anterior descending artery was left unoccluded to serve as a control. Eight weeks postoperatively, pigs were assigned to sedentary (n=14) or exercise training (n=13; progressive treadmill training for 13 weeks) regimens. Coronary arterioles (75–150 μm) and small arteries (250–400 um) were isolated from myocardium of the left circumflex and left anterior descending regions. Immunoblot analysis indicated that H2O2 induced PKG dimer formation in both porcine coronary arterioles and small arteries. Chronic coronary artery occlusion appeared to diminish H2O2‐mediated PKG dimer formation in collateral‐dependent arterioles and the reduced dimerization persisted with exercise training. H2O2‐mediated vasodilation tended to be impaired in arterioles isolated from the collateral‐dependent regions of sedentary pigs and was partially restored with exercise training. It also appears that both Kv and BKCa channels contributed to H2O2‐mediated dilation after exercise training. Our data demonstrate that H2O2 stimulates PKG dimer formation in both porcine coronary arterioles and small arteries. Contrary to our hypothesis, H2O2‐induced PKG dimerization is not enhanced by exercise training in either nonoccluded or collateral‐dependent arterioles. However, both Kv and BKCa channels appear to contribute to exercise training‐enhanced H2O2‐mediated dilation in collateral‐dependent coronary arterioles.Support or Funding InformationNational Institutes of Health R01‐HL139903

Хроническая коронарная окклюзия в стенте. Эффективность реваскуляризации и техника выполнения

Хроническая коронарная окклюзия в стенте. Эффективность реваскуляризации и техника выполнения

ASSOCIATION BETWEEN CORONARY COLLATERALS AND MYOCARDIAL VIABILITY IN PATIENTS WITH A CHRONIC TOTAL OCCLUSION

Current guidelines advocate viability assessment before revascularization of chronic coronary total occlusions (CTO). The present study evaluated associations between coronary collaterals and myocardial viability assessed by cardiac magnetic resonance (CMR) imaging in patients with a CTO. Patients

Prospective, Multicentric Observational Study Evaluating the Management of Chronic Coronary Occlusions In France

Prospective, Multicentric Observational Study Evaluating the Management of Chronic Coronary Occlusions In France

Clinical case of retrograde endovascular recanalization of chronic coronary occlusion

Coronary chronic occlusion (CCO) occurs in ~20% of cases when coronary angiography is performed in patients with coronary artery disease. According to large observational studies and registries, it is known that most patients with CCO receive only drug therapy. Only 20-22% of patients with CCO undergo surgical myocardial revascularization. Such a low percentage can be explained by a low success rate and a large number of complications during recanalization of CCO at the development stage of endovascular surgery. The accumulation of experience and the improvement of technical equipment has significantly increased the success rate of endovascular revascularization of CCO and reduced the number of complications. More and more scientific evidence has appeared in favor of the recanalization of CCO. It is known that the myocardium in the area of the occluded artery is in ischemia. The presence of a developed system of collateral circulation allows us to ensure sufficient blood flow in the myocardium only at rest, but with a load of collateral blood supply is not enough. Recanalization of CCO can eliminate myocardial ischemia, improve systolic function of the left ventricular myocardium, increase exercise tolerance and improve the quality of life of patients.

P5748Impact of specific crossing techniques in chronic total occlusion percutaneous coronary intervention on recovery of absolute myocardial perfusion

Abstract Background Multiple techniques in chronic coronary total occlusion (CTO) percutaneous coronary intervention (PCI) have been developed to cross CTOs. Purpose To compare recovery of quantitative myocardial blood flow (MBF) after different CTO PCI techniques. Methods Consecutive patients with [15O]H2O positron emission tomography perfusion imaging before and three months after successful CTO PCI were included. Change in quantitative hyperemic MBF, coronary flow reserve (CFR) and perfusion defect size were compared between antegrade wire escalation (AWE), retrograde wire escalation (RWE), antegrade dissection and reentry (ADR) and retrograde dissection and reentry (RDR), and further between specific subintimal crossing and reentry techniques. Results 193 patients were treated with AWE (N=90), RWE (N=24), ADR (N=35) and RDR (N=44). Significant improvements (all p&lt;0.01) in hyperemic MBF (1.19±0.77, 0.94±0.65, 1.09±0.63, and 1.02±0.75 mL min–1 g–1, respectively), CFR (1.34±1.08, 1.14±1.09, 1.31±0.96, and 1.24±0.99, respectively), and perfusion defect size (3.17±2.13, 3.00±2.21, 2.74±2.09, and 2.93±1.92 segments, respectively) were comparable between the four approaches (p=0.40, p=0.84, and p=0.77, respectively). Recovery of hyperemic MBF was less pronounced after subintimal crossing with a knuckle-wire-technique compared to the use of CrossBoss in controlled ADR and RDR (p=0.02), and less after reentry with subintimal tracking and reentry (STAR) in ADR compared with controlled ADR (Stingray) or limited antegrade subintimal tracking (LAST) (p=0.02 and p&lt;0.01). Conclusions Recovery of hyperemic MBF, CFR, and perfusion defect size was significant after CTO PCI and comparable between different crossing techniques. Improvement of hyperemic MBF was inferior after using the knuckle-wire subintimal crossing technique and STAR compared to other subintimal crossing and reentry techniques. Acknowledgement/Funding None