Search

Background: Antegrade wiring is the most commonly used chronic total occlusion (CTO) crossing technique., Methods: Using data from the PROGRESS CTO registry (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; Clinicaltrials.gov identifier: NCT02061436), we examined the clinical and angiographic characteristics and procedural outcomes of CTO percutaneous coronary interventions (PCIs) performed using a primary antegrade wiring strategy., Results: Of the 13 563 CTO PCIs performed at 46 centers between 2012 and 2023, a primary antegrade wiring strategy was used in 11 332 (83.6%). Upon multivariable logistic regression analysis, proximal cap ambiguity (odds ratio [OR]: 0.52; 95% CI, 0.46-0.59), side branch at the proximal cap (OR: 0.85; 95% CI, 0.77-0.95), blunt/no stump (OR: 0.52; 95% CI: 0.47-0.59), increasing lesion length (OR [per 10 mm increase]: 0.79; 95% CI, 0.76-0.81), moderate to severe calcification (OR: 0.73; 95% CI, 0.66-0.81), moderate to severe proximal tortuosity (OR: 0.67; 95% CI, 0.59-0.75), bifurcation at the distal cap (OR: 0.66; 95% CI, 0.59-0.73), left anterior descending artery CTO (OR [vs right coronary artery]: 1.44; 95% CI, 1.28-1.62) and left circumflex CTO (OR [vs right coronary artery]: 1.22; 95% CI, 1.07-1.40), non-in-stent restenosis lesion (OR: 0.56; 95% CI, 0.49-0.65), and good distal landing zone (OR: 1.18; 95% CI, 1.06-1.32) were independently associated with primary antegrade wiring crossing success., Conclusions: The use of antegrade wiring as the initial strategy was high (83.6%) in our registry. We identified several parameters associated with primary antegrade wiring success.

Background: There is variability in clinical and lesion characteristics as well as techniques in chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We analyzed patient and lesion characteristics, techniques, and outcomes in 11 503 CTO-PCI procedures performed in North America (NA) and in the combined regions of Europe, Asia, and Africa from 2017 to 2023 as documented in the PROGRESS-CTO registry., Results: Eight thousand four hundred seventy-nine (74%) procedures were performed in NA. Compared with non-NA patients, NA patients were older, with higher body mass index and higher prevalence of diabetes, hypertension, dyslipidemia, family history of coronary artery disease, prior history of PCI, coronary artery bypass graft surgery and heart failure, cerebrovascular disease, and peripheral arterial disease. Their CTOs were more complex, with higher J-CTO (2.56 ± 1.22 vs 1.81 ± 1.24; P less than .001) and PROGRESS-CTO (1.29 ± 1.01 vs 1.07 ± 0.95; P less than .001) scores, longer length, and higher prevalence of proximal cap ambiguity, blunt/no stump, moderate to severe calcification, and proximal tortuosity. Retrograde (31.0% vs 22.1%; P less than .001) and antegrade dissection and re-entry (ADR) (21.2% vs 9.2%; P less than .001) were more commonly used in NA centers, along with intravascular ultrasound (69.0% vs 10.1%; P less than .001). Procedure and fluoroscopy times were longer in NA, while contrast volume and radiation dose were lower. Technical (86.7% vs 86.8%; P > .90) and procedural (85.4% vs 85.8%; P = .70) success and in-hospital major adverse cardiovascular events (MACE) (1.9% vs 1.7%; P = .40) were similar in NA and non-NA centers., Conclusions: Compared with non-NA patients, NA patients undergoing CTO PCI have more comorbidities, higher CTO lesion complexity, are more likely to undergo treatment with retrograde and ADR, and have similar technical success and MACE.

Successful collateral channel (CC) crossing is essential for the success of retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Based on the Japanese CTO PCI expert registry, the J-Channel score was developed to predict CC crossing. We examined the performance of the J-Channel score in patients who underwent retrograde CTO-PCI at 31 centers between 2013-2023 as part of the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO). We observed an association between successful CC crossing and the J-Channel score, its predictive efficacy was modest for both wire and microcatheter crossing.

Ranolazine is an anti-anginal medication given to patients with chronic angina and persistent symptoms despite medical therapy. We examined 11 491 chronic total occlusion (CTO) percutaneous coronary interventions (PCI) that were performed at 41 US and non-US centers between 2012 and 2023 in the PROGRESS-CTO Registry. Patients on ranolazine at baseline had more comorbidities, more complex lesions, lower procedural and technical success (based on univariable but not multivariable analysis), and higher incidence of major adverse cardiac events (MACE) (on both univariable and multivariable analysis).

Background: There is limited data on equipment loss or entrapment during chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We analyzed the baseline clinical and angiographic characteristics and outcomes of equipment loss/entrapment at 43 US and non-US centers between 2017 and 2023., Results: Equipment loss/entrapment was reported in 40 (0.4%) of 10 719 cases during the study period. These included guidewire entrapment/fracture (n = 21), microcatheter entrapment/fracture (n = 11), stent loss (n = 8) and balloon entrapment/fracture/rupture (n = 5). The equipment loss/entrapment cases were more likely to have moderate to severe calcification, longer lesion length, higher J-CTO and PROGRESS-CTO complications scores, and use of the retrograde approach compared with the remaining cases. Retrieval was attempted in 71.4% of the guidewire, 90.9% of the microcatheter, 100% of the stent loss, and 100% of the balloon cases, and was successful in 26.7%, 30.0%, 50%, and 40% of the cases, respectively. Procedures complicated by equipment loss/entrapment had higher procedure and fluoroscopy time, contrast volume and patient air kerma radiation dose, lower procedural (60.0% vs 85.6%, P less than .001) and technical (75.0% vs 86.8%, P = .05) success, and higher incidence of major adverse cardiac events (MACE) (17.5% vs 1.8%, P less than .001), acute MI (7.5% vs 0.4%, P less than .001), emergency coronary artery bypass graft (CABG) (2.5% vs 0.1%, P = .03), perforation (20.0% vs 4.9%, P less than .001), and death (7.5% vs 0.4%, P less than .001)., Conclusions: Equipment loss is a rare complication of CTO PCI; it is more common in complex CTOs and is associated with lower technical success and higher MACE.

Objectives: There is limited data on race and outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The authors sought to evaluate CTO PCI techniques and outcomes in different racial groups., Methods: We examined the baseline characteristics and procedural outcomes of 11 806 CTO PCIs performed at 44 US and non-US centers between 2012 and March 2023. In-hospital major adverse cardiac events (MACE) included death, myocardial infarction, repeat target-vessel revascularization, pericardiocentesis, cardiac surgery, and stroke prior to discharge., Results: The most common racial group was White (84.5%), followed by Black (5.7%), "Other" (3.9%), Hispanic (2.9%), Asian (2.4%), and Native American (0.7%). There were significant differences in the baseline characteristics between different racial groups. When compared with non-White patients, the retrograde approach and antegrade dissection re-entry were more likely to be the successful crossing strategies in White patients without any significant differences in technical success (86.4% vs 86.4%; P = .93), procedural success (84.8% vs 85.0%; P = .79), and in-hospital MACE (2.0% vs 1.5%; P = .15) between the 2 groups. The technical success rate was significantly higher in the "Other" racial group (91.0% vs 86.4% in White, 86.9% in Asian, 84.5% in Black, 84.5% in Hispanic, and 83.3% in Native American; P = .03) without any significant differences in procedural success or in-hospital MACE rates between the groups., Conclusions: Despite differences in baseline characteristics and procedural techniques, the procedural success and in-hospital MACE of CTO PCI were not significantly different between most racial groups.

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) continues to evolve. This review summarizes recent publications categorized by outcomes, techniques, complications, and ongoing studies in this rapidly growing area.

Background: The optimal range of activated clotting time (ACT) in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study., Methods: We examined the association between ACT and in-hospital ischemic and bleeding outcomes in patients who underwent CTO PCI in the Prospective Global Registry for the Study of CTO Intervention., Results: ACT values were available for 4377 patients who underwent CTO PCI between 2012 and 2023 at 29 centers. The mean ACT distribution was less than 250 seconds (19%), 250 to 349 seconds (50%), and greater than or equal to 350 seconds (31%). The incidence of ischemic events, bleeding events, and net adverse cardiovascular events (NACE) was 0.8%, 3.0%, and 3.8%, respectively. In multiple logistic regression analysis, increasing nadir ACT was associated with decreasing ischemic events (adjusted odds ratio [aOR] per 50-second increments: 0.69 [95% confidence interval (CI), 0.50-0.94; P=.017]; and increasing peak ACT was associated with increasing bleeding events (aOR per 50-second increments: 1.17 [95% CI ,1.01-1.36; P=.032]). A U-shaped association was seen between mean ACT and NACE, where restricted cubic spline analysis demonstrated that patients with a low ( less than 200 seconds) or high ( greater than 400 seconds) ACT had increasing NACE risk compared with an ACT of 200 to 400 seconds (aOR 2.06, 95% CI 1.18-3.62; P=.012)., Conclusions: Among patients who underwent CTO PCI, mean ACT had a U-shaped relationship with NACE, where patients with a low ( less than 200 seconds) ACT (driven by ischemic events) or high ( greater than 400 seconds) ACT (driven by bleeding) had higher NACE compared with an ACT of 200 to 400 seconds.

Objectives: Ostial CTOs can be challenging to revascularize. We aim to describe the outcomes of ostial chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We examined the clinical and angiographic characteristics and procedural outcomes of 8788 CTO PCIs performed at 35 US and non-US centers between 2012 and 2022. In-hospital major adverse cardiac events (MACE) included death, myocardial infarction, urgent repeat target-vessel revascularization, tamponade requiring pericardiocentesis or surgery, and stroke., Results: Ostial CTOs constituted 12% of all CTOs. Patients with ostial CTOs had higher J-CTO score (2.9 ± 1.2 vs 2.3 ± 1.3; P less than .01). Ostial CTO PCI had lower technical (82% vs. 86%; P less than .01) and procedural (81% vs. 85%; P less than .01) success rates compared with non-ostial CTO PCI. Ostial location was not independently associated with technical success (OR 1.03, CI 95% 0.83-1.29 P =.73). Ostial CTO PCI had a trend towards higher incidence of MACE (2.6% vs. 1.8%; P =.06), driven by higher incidence of in-hospital death (0.9% vs 0.3% P less than.01) and stroke (0.5% vs 0.1% P less than .01). Ostial lesions required more often use of the retrograde approach (30% vs 9%; P less than .01). Ostial CTO PCI required longer procedure time (149 [103,204] vs 110 [72,160] min; P less than .01) and higher air kerma radiation dose (2.3 [1.3, 3.6] vs 2.0 [1.1, 3.5] Gray; P less than .01)., Conclusions: Ostial CTOs are associated with higher lesion complexity and lower technical and procedural success rates. CTO PCI of ostial lesions is associated with frequent need for retrograde crossing, higher incidence of death and stroke, longer procedure time and higher radiation dose.

Background: There is limited information on the impact of the target vessel on the procedural techniques and outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We analyzed the baseline clinical and angiographic characteristics and procedural outcomes of 11,580 CTO PCIs performed between 2012 and 2022 at 44 centers., Results: The most common CTO target vessel was the right coronary artery (RCA) (53.1%) followed by the left anterior descending artery (LAD) (26.0%) and the left circumflex artery (LCX) (19.8%). RCA CTOs were longer and more complex, with a higher Japanese CTO score compared with LAD or LCX CTOs. Technical success was higher among LAD (88.8%) lesions when compared with RCA (85.7%) or LCX (85.8%) lesions (P less than .001). The incidence of major adverse cardiovascular events (MACE) was overall 1.9% (n = 220) and was similar among target vessels (P=.916). There was a tendency toward more frequent utilization of the retrograde approach for more proximal occlusions in all 3 target vessels. When compared with all other RCA lesions combined, distal RCA lesions had higher technical success (87.7% vs 85.3%; P=.048). Technical success was similar between various locations of LAD CTOs (P=.704). First/second/third obtuse marginal branch had lower technical success when compared with all other LCX lesion locations (82.7% vs 86.8%; P=.014). There was no association between MACE and CTO location in all 3 target vessels., Conclusions: LAD CTO PCIs had higher technical and procedural success rates among target vessels. The incidence of MACE was similar among target vessels and among various locations within the target vessel.

Background: We examined the effect of atrial fibrillation on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We examined the baseline characteristics and procedural outcomes of 9,166 CTO PCIs performed at 39 US and non-US centers between 2012 and 2023., Results: Atrial fibrillation was present in 1122 (12%) patients. These patients were older and had a higher incidence of comorbidities, such as hypertension, dyslipidemia, heart failure, cerebrovascular disease, and peripheral arterial disease, lower left ventricular ejection fraction, and lower eGFR. Their CTOs were more likely to have moderate to severe calcification and longer lesion length. They also had higher mean J-CTO and PROGRESS-CTO complications (Acute MI, MACE, Mortality, Perforation, and Pericardiocentesis) scores. Patients with atrial fibrillation had higher prevalence of uncrossable and undilatable CTO lesions and required longer procedure (107 vs 119 min; P less than .001) and fluoroscopy (40 vs 43 min; P=.005) time. Technical success and MACE, including procedural/in-hospital bleeding, were similar in patients with and without atrial fibrillation. Although the crude incidence of MACE on follow-up (median 61 days) was significantly higher in patients with atrial fibrillation, the latter was not independently associated with adverse events on Cox proportional hazards analysis., Conclusions: Patients with atrial fibrillation undergoing CTO PCI are older, have more comorbidities, higher lesion complexity, and longer procedure time, but similar technical success and in-hospital MACE. They have higher MACE and mortality during follow-up, but the difference is not significant after adjusting for potential confounding variables.

Background: Although discouraged, ad hoc chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is occasionally performed., Methods: We examined the clinical, angiographic characteristics, and procedural outcomes of patients who underwent ad hoc CTO PCI in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO, NCT02061436)., Results: Of the 10,998 patients included in the registry, 899 (8.2%) underwent ad hoc CTO PCI. The incidence of ad hoc CTO PCI decreased from 18% in 2016 to 3% in 2022. Ad hoc CTO PCI patients had a lower prevalence of comorbidities and less complex angiographic characteristics demonstrated by lower J-CTO score (1.9±1.2 vs 2.4±1.3, P < .001). In these patients, PROGRESS-CTO major adverse cardiovascular events (MACE) (1.9±1.4 vs 2.5±1.7), mortality (1.2±1.0 vs 1.6±1.1), and perforation (1.5±1.2±2.2 vs 1.5) scores were lower (P < .001). Technical success was similar between the groups (86%). MACE were lower in the ad hoc CTO PCI group (.8% vs 2.0%, P=.009). Ad hoc CTO PCI was not associated with MACE after adjusting for potential confounders, odds ratio: .69 (95% confidence interval, .30-1.57). In patients with higher J-CTO scores, planned CTO PCI was associated with higher technical success (P < .001)., Conclusion: Approximately 8% of CTO PCI procedures are performed ad hoc, usually in less complex lesions and patients with lower complication risk. While ad hoc CTO PCI might be appropriate for carefully selected cases, a staged approach is recommended for most CTO PCI.

Background: Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) lesions can be challenging to perform. In the present review we summarize recent publications in this rapidly evolving area grouped according to indications, outcomes, technique, and complications.

Background: There are limited data on the use of bivalirudin for chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We compared CTO-PCIs performed using bivalirudin vs unfractionated heparin in the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO; NCT02061436). The primary endpoint was net adverse cardiac events (NACE), defined as major adverse cardiac events (MACE) and vascular complications., Results: Between 2012 and 2022, a total of 73 of 9723 procedures (0.75%) were performed using bivalirudin. The J-CTO score (2.4 ± 1.2 vs 2.4 ± 1.3; P=.73) and the PROGRESS-CTO score (1.4 ± 0.9 vs 1.2 ± 1.0; P=.31) were similar in both groups, and the retrograde approach was used less often in the bivalirudin group (15% vs 30%; P<.01). Procedural success (89% vs 85%; P=.35), in-hospital NACE (1.4% vs 2.1%; P>.99), incidence of MACE (0% vs 0.76%; P=.64), and vascular access complications (1.4% vs 0.9%; P=.48) were not different between the 2 groups. On multivariable analysis, use of bivalirudin was not associated with an increased risk of NACE (odds ratio, 0.99; 95% confidence interval, 0.13-7.27)., Conclusion: Bivalirudin is infrequently used during retrograde CTO-PCI. While the incidence of adverse events was similar with unfractionated heparin, larger studies are needed to assess the safety of bivalirudin.

Background: Guidewires and microcatheters are critical to the success of chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We examined equipment utilization in 11,202 CTO-PCIs performed in 10,952 patients at 42 United States (US) and non-US centers between 2012 and 2022., Results: Antegrade-only crossing was attempted in 7628 CTO-PCIs (68%) and the retrograde approach was used in 3574 CTO-PCIs (32%). The median number of guidewires used during antegrade wiring increased with lesion complexity from 3 (interquartile range [IQR], 2-4) for J-CTO score of 0 to 5 (IQR, 4-7) for J-CTO score of 5 (P<.001). Antegrade-only procedures had higher technical (90% vs 79%; P<.001) and procedural success (89% vs 77%; P<.001) compared with retrograde procedures. In antegrade-only cases, Pilot 200 (28%; Abbott Vascular) and Fielder XT (24%; Asahi Intecc) were the most frequently used guidewires, while Corsair (21%; Asahi Intecc) and Turnpike Spiral (20%; Vascular Solutions) were the most commonly used microcatheters. In retrograde cases, Sion (32%; Asahi Intecc) was the most common guidewire used, followed by Sion Black (22%; Asahi Intecc), Pilot 200 (22%), and Suoh 03 (19%; Asahi Intecc), while Corsair (16%) and Turnpike LP (11%) were the most commonly used microcatheters. The most successful guidewire for collateral crossing was the Sion (32%), followed by Sion Black (15%) and Suoh 03 (11%)., Conclusion: Polymer-jacketed guidewires are the most commonly used guidewires for antegrade wiring, while non-polymer-jacketed, torquable guidewires are the most frequently used guidewires for retrograde techniques. Turnpike and Corsair are the most commonly used microcatheters in CTO-PCI.

Background: The prevalence and outcomes of patients who presented with an acute coronary syndrome (ACS) and underwent chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have received limited study., Methods: We examined the clinical characteristics and procedural outcomes of ACS patients who underwent CTO-PCI in the Prospective Global Registry for the Study of CTO Intervention (PROGRESS-CTO; NCT02061436)., Results: Of the 8826 patients who underwent CTO-PCI between 2012 and 2022 at 38 centers, 558 (6.3%) presented with ACS. ACS presentation was with non-ST-segment elevation myocardial infarction (MI) in 54%, unstable angina in 33%, and ST-segment elevation MI in 6.5%. ACS patients were older (66 ± 11 years vs 64 ± 10 years; P<.001) and had higher prevalence of comorbidities such as diabetes mellitus (48% vs 42%; P=.02), prior MI (52% vs 45%; P<.01), and lower left ventricular ejection fraction (49 ± 14% vs 51 ± 13%; P<.01). While the PROGRESS-CTO score (1.4 ± 1.0 vs 1.2 ± 1.0; P<.001) was higher in the ACS group, the J-CTO score was comparable (2.3 ± 1.2 vs 2.4 ± 1.3; P=.68). Technical success (88% vs 86%; P=.12) and the incidence of in-hospital major adverse cardiovascular event (MACE) (0.9% vs 2.1%; P=.06) and adverse events at 3-month follow-up (3.4% vs 7.2%; Kaplan-Meier log-rank P=.16) were similar between ACS and non-ACS patients, respectively., Conclusion: Approximately 6% of patients who underwent CTO-PCI presented with an ACS. Technical success, in-hospital MACE, and the incidence of adverse events up to 3 months were similar between patients who presented with vs without an ACS.

Objectives: There are limited data on the association of operator volume with the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI)., Methods: We analyzed the association between operator volume and procedural outcomes of 7035 CTO-PCIs performed between 2012 and February 2021 at 30 centers., Results: The study population was divided into 3 groups based on annual operator CTO-PCI volume: low-volume operators (LVO: &lt;30 cases/year; 39.7% of the cases); medium-volume operators (MVO: 30-60 cases/year; 25.7% of the cases); and high-volume operators (HVO: &gt;60 cases/ year; 34.6% of the cases). Mean patient age was 64.4 ± 10 years and 82% were men. Cases performed by HVOs were more complex, with higher J-CTO score compared with cases performed by MVOs and LVOs (2.72 ± 1.27 vs 2.39 ± 1.19 vs 2.12 ± 1.27, respectively; P&lt;.001). Moderate/severe proximal vessel tortuosity (35% vs 23% vs 20%; P&lt;.001) and proximal cap ambiguity (44% vs 34% vs 32%; P&lt;.001) was also more common in the HVO group. Cases performed by HVOs had higher technical success rates (87.9% vs 86.9% vs 82.6%; P&lt;.001), but also higher rates of periprocedural major cardiac adverse events compared with MVOs and LVOs (3.08% vs 2.71% vs 1.50%; P&lt;.01). On multivariable analyses, HVOs and MVOs were associated with higher technical success., Conclusions: In a contemporary, multicenter registry, 40% of CTO-PCI cases are performed by LVOs performing &lt;30 cases per year. Cases performed by HVOs were associated with higher technical and procedural success, but also higher periprocedural major complication rates, potentially due to higher lesion complexity.

Background: The retrograde approach to coronary chronic total occlusions (CTOs) can be used as the initial crossing strategy (primary retrograde) or after failure of antegrade crossing attempts (secondary retrograde)., Methods: We compared baseline clinical and angiographic characteristics and procedural outcomes of primary vs secondary retrograde crossing for CTO percutaneous coronary intervention (PCI) among 2789 procedures performed at 34 centers between 2012 and 2021., Results: Retrograde CTO-PCI was performed as the primary crossing strategy in 1086 cases (38.9%) and as a secondary approach in 1703 cases (61.1%). Patients in the primary group had slightly lower left ventricular ejection fraction (49.1% vs 50.4%; P=.02), were more likely to have had prior coronary artery bypass graft surgery (52.9% vs 38.4%; P&lt;.001), and had higher J-CTO (3.31 ± 0.98 vs 2.99 ± 1.09; P&lt;.001) and PROGRESS-CTO scores (1.47 ± 0.92 vs 1.29 ± 0.99; P&lt;.001). Technical (81.4% vs 77.3%; P=.01) and procedural success rates (78.6% vs 74.1%; P&lt;.01) were higher in the primary retrograde group, with no difference between in-hospital major adverse event rates (4.3% vs 4.0%; P=.66). Contrast volume (250 mL [interquartile range (IQR), 176-347] vs 270 mL [IQR, 190-367]; P&lt;.001) and procedure time (175 minutes [IQR, 127-233] vs 180 minutes [IQR, 142-236]; P&lt;.001) were lower in the primary group., Conclusions: Use of retrograde approach as the primary crossing strategy is associated with higher rates of technical and procedural success and similar rates of in-hospital major adverse cardiac events compared with secondary retrograde CTO-PCI.

Background: The use of retrograde crossings in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) provides higher technical success rates in CTO-PCI. However, the use of epicardial collaterals carries a higher complication risk., Methods and Results: In this study, we aimed to investigate the temporal trends in retrograde crossing of epicardial collaterals, introduction of new guidewires, in-hospital major adverse cardiovascular events (MACE), and technical success rates in a large, multinational registry. We demonstrate that technical success rates increased substantially from about 5%-10% to 76% in the past decade without a concomitant increase in MACE rate (~3% to 4%), likely associated with increased operator experience and introduction of new guidewires. In addition, we show that while high-volume centers have higher technical success, they also have higher perforation rates.