Calcified Chronic Total Occlusion Research Articles

A case report of ventricular fibrillation following Shockwave intravascular lithotripsy during percutaneous coronary intervention

BackgroundShockwave intravascular lithotripsy (S-IVL) is widely used during percutaneous coronary intervention (PCI) of calcified coronary arteries. Ventricular capture beats during S-IVL are common but arrhythmias are rare.Case presentationA 75-year-old woman was scheduled for PCI to a short, heavily calcified chronic total occlusion of the right coronary artery. After wiring of the occlusion, S-IVL was used to predilated the calcified stenosis. During S-IVL, the patient developed ventricular fibrillation twice.ConclusionTo our knowledge, this is only the second reported case of VF during S-IVL. Although very rare, it is important to be aware of this potential and serious complication.

Role of intravascular ultrasound for the technical assessment of endovascular reconstruction of the aortic bifurcation

ObjectiveThe aim of this study was to evaluate the role of intravascular ultrasound (IVUS) for the technical assessment of kissing stents (KSs) and covered endovascular reconstruction of the aortic bifurcation (CERAB) in the treatment of aortoiliac obstructive disease involving the aortic bifurcation. MethodsWe conducted a single-center retrospective review of patients undergoing endovascular treatment of severe aorto-iliac obstructive disease (2019-2023). IVUS was performed in patients treated by KSs or CERAB according to preoperative indications, in cases of moderate/severe calcifications, mural thrombus, total occlusions, and lesion extension towards the proximity of renal or hypogastric arteries. Indications for IVUS-guided intraoperative revisions were residual stenosis or compression >30%, incomplete stent-to-wall apposition, or flow-limiting dissection at the landing site. Follow-up assessment was performed at 6 and 12 months, and then yearly. Thirty-day outcomes and 2-year patency rates were evaluated. Logistic regression was used to identify factors associated with significant technical defects detected by IVUS needing intraoperative revision. ResultsIVUS was used for the technical assessment of 102 patients treated by KSs (n = 57; 56%) or CERAB (n = 45; 44%) presenting with severe intermittent claudication (39%), rest pain (39%), or ischemic tissue loss (25%). Twenty-nine significant technical defects were identified by IVUS in 25 patients (25%) who then had successful intraoperative correction by additional ballooning (n = 23; 80%) or stenting (n = 6; 20%). Patients with a severely calcified chronic total occlusion (odds ratio, 1.85; 95% confidence interval, 1.01-5.27; P = .044) or severely calcified narrow aortic bifurcation with <12 mm diameter (odds ratio, 2.34; 95% confidence interval, 1.10-8.64; P = .032) were at increased risk for IVUS-guided intraoperative revision. There were no postoperative deaths and no major adverse events. Two-year primary patency was 100%. ConclusionsIVUS was used for the technical assessment of KSs/CERAB in a selected cohort of patients with severe aorto-iliac obstructive disease. This allowed the identification and intraoperative correction of a significant technical defect not detected by completion angiogram in one-quarter of patients, achieving optimal 2-year results. IVUS assessment of KSs/CERAB may be considered especially in patients with a calcified total occlusion or narrow aortic bifurcation.

Abstract 12812: Temporal Trends of Calcium Modification Therapies in Chronic Total Occlusion Percutaneous Coronary Intervention

Introduction: Various techniques with different mechanisms of action are presently available for the modification of coronary calcium in chronic total occlusions (CTOs). Hypothesis: We sought to examine the temporal trends in the use of calcium modification therapies in a large multicenter CTO percutaneous coronary intervention (PCI) registry. Methods: We analyzed data from 13,079 CTO PCIs performed in 12,799 patients at 46 US and non-US centers between 2012 and 2023. Calcification was assessed by angiography as mild (spots), moderate (involving ≤50% of the reference lesion diameter), or severe (involving &gt;50% of the reference lesion diameter). Results: Moderate or severe calcification was present in 6,094 CTOs (46.6%). Among CTO lesions with moderate or severe calcium, one or more calcium modification techniques was used in 1,006 cases (16.9%); rotational atherectomy (7.2%, n=434), laser atherectomy (3.4%, n=203), intravascular lithotripsy (IVL) (3.4%, n=200), scoring balloon (3.0%, n=178), cutting balloon (1.8%, n=109), orbital atherectomy (1.5%, n=91), and Chocolate balloon (Teleflex, 0.3%, n=15). Over time, the use of calcium modification techniques for lesions with moderate to severe calcification increased from 2.5% in 2012 to 25.7% in 2023 (p for trend &lt;0.001), with a significant increase in the use of IVL (from 0.6% in 2020 to 16.6% in 2023; p for trend &lt;0.001) (Central Illustration). In the last 2 years (2021-2023), IVL was the most commonly used calcium modification technique followed by rotational atherectomy. Conclusions: The use of calcium modification techniques for calcified CTO lesions increased over time, with a significant increase in the use of IVL in the last years.

Abstract 16998: A Novel Preclinical Model of Calcified Coronary Chronic Total Occlusion

Introduction: These is significant research into the development of new medications and devices to treat chronic total occlusions (CTO). However, there is a lack of large animal models which reproduce the anatomy of clinical CTOs. Aim: Create an experimental model that mimics the anatomic features of human CTOs. Methods: CTOs were created in coronary arteries of live Yorkshire pigs (weight 80-120 lbs). The bioactive dental plug material (OsteoGen® Plug, Impladent Ltd) was implanted into the middle segment of one of coronary arteries (LAD, LCX or RCA). Angiography (C- Arm, Siemens) was performed before, immediately after plug implantation and before autopsy to confirm the presence of a CTO lesion. Animals were sacrificed at 9 hours to 3 months (n=12) and all coronary arteries underwent histopathological examination. Results: Histopathologic assessment confirmed that the bioactive plug composed of calcium apatite crystals and bovine collagen matrix mimics the pathological appearances of human CTOs. Serial histological sections showed complete resorption of the collagen matrix with replacement by fibrotic tissue 2 months after plug implantation, while the calcium content remains in the CTO. Conclusions: We have developed a reproducible model of calcified CTOs in pigs. Our model can provide a platform for evaluation of new drugs and devices for the treatment of calcified CTOs as well as to serve as a live model for training interventional cardiologists learning to cross CTOs.

Shockwave intravascular lithotripsy as a novel strategy for balloon undilatable heavily calcified chronic total occlusion lesions.

The successful percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) improves the long-term outcome in patients with coronary artery disease (CAD). Heavy calcification remains one of the strongest predictors of an unfavorable outcome of PCI. In this case series study, shockwave intravascular lithotripsy (S-IVL)-a novel balloon-based coronary system facilitating modification of calcified coronary lesions was evaluated. The study population consisted of five heavily calcified, undilatable-CTOs lesions treated with S-IVL selected out of all consecutive CTO-PCI patients performed at two high-volume cardiac centers. The registry included 5 patients successful CTO - S-IVL procedures with an average J-CTO of 2.6 points. In the short-term follow-up period, including the first 30 days, no cases of acute in-stent thrombosis, target lesion failure, or major adverse cardiac and cerebrovascular events were noted. The present data suggest that this approach can be safe and useful in the treatment of complex calcified CTO lesions.

Contemporary issues of percutaneous coronary intervention in heavily calcified chronic total occlusions: an expert review from the European CTO Club.

Severe calcification is frequent in coronary chronic total occlusions (CTO), and its presence has been associated with increased procedural complexity and poor long-term outcomes following percutaneous coronary intervention (PCI) in an already challenging anatomical setting. The diagnostic characterisation of heavily calcified CTOs using non-invasive and invasive imaging tools can lead to the application of different therapeutic options during CTO PCI, in order to achieve adequate lesion preparation and optimal stent implantation. In this expert review, the European Chronic Total Occlusion Club provides acontemporary, methodological approach, specifically addressing heavily calcified CTOs, suggesting an integration of evidence-based diagnostic methods to tailored, up-to-date percutaneous therapeutic options.

Long-Term Outcomes after Rotational Atherectomy for Calcified Chronic Total Occlusion versus Nonchronic Total Occlusion Coronary Lesions.

The role of rotational atherectomy (RA) in contemporary percutaneous coronary intervention (PCI) is expanding to include certain chronic total occlusion (CTO) lesions. However, the long-term outcome of RA in CTOs is still unclear. To investigate in-hospital and long-term outcomes after RA for CTO compared to non-CTO calcified lesions. Moreover, this report evaluates the role of the elective RA approach in calcified CTOs. This study enrolled 812 patients (869 lesions; CTO, n = 80 versus non-CTO, n = 789). The mean age of the study population was 73.1 ± 8.6 years, the baseline characteristics were comparable in both groups. Balloon-resistant CTO lesions represented the main indication for RA in CTO patients (61.2%). The mean J-CTO score was 2.42 ± 0.95. The angiographic success rate was lower in CTO patients (88.8% vs 94.9%; p = 0.022). In-hospital major adverse cardiac events (MACE) rate was comparable in both groups (CTO 8.8% vs 7.0% in non-CTO;p = 0.557). At two-year follow-up, a higher target lesion failure (TLF) was observed in CTO group (25.5% vs 15.1%, log rank p = 0.041), driven by higher cardiac mortality while the clinically driven target lesion revascularisation (TLR) was comparable between the study groups. Elective RA for CTO had a shorter procedural time and lower rate of dissection (7.5% vs 25%; p = 0.030) compared to bail-out RA with similar long-term outcomes. Compared to non-CTO, RA for CTO can be performed with a high procedural success rate and comparable in-hospital outcomes. Apart from higher cardiac mortality in the CTO group, the long-term outcomes are comparable in both groups. Elective RA is a feasible and beneficial approach to be used in CTO intervention.

Dual-Resonance (16/32 MHz) Piezoelectric Transducer With a Single Electrical Connection for Forward-Viewing Robotic Guidewire.

Peripheral artery disease (PAD) affects more than 200 million people globally. Minimally invasive endovascular procedures can provide relief and salvage limbs while reducing injury rates and recovery times. Unfortunately, when a calcified chronic total occlusion is encountered, ~25% of endovascular procedures fail due to the inability to advance a guidewire using the view provided by fluoroscopy. To enable a sub-millimeter, robotically steerable guidewire to cross these occlusions, a novel single-element, dual-band transducer is developed that provides simultaneous multifrequency, forward-viewing imaging with high penetration depth and high spatial resolution while requiring only a single electrical connection. The design, fabrication, and acoustic characterization of this device are described, and proof-of-concept imaging is demonstrated in an ex vivo porcine artery after integration with a robotically steered guidewire. Measured center frequencies of the developed transducer were 16 and 32 MHz, with -6 dB fractional bandwidths of 73% and 23%, respectively. When imaging a 0.2-mm wire target at a depth of 5 mm, measured -6 dB target widths were 0.498 ± 0.02 and 0.268 ± 0.01 mm for images formed at 16 and 32 MHz, respectively. Measured SNR values were 33.3 and 21.3 dB, respectively. The 3-D images of the ex vivo artery demonstrate high penetration for visualizing vessel morphology at 16 MHz and ability to resolve small features close to the transducer at 32 MHz. Using images acquired simultaneously at both frequencies as part of an integrated forward-viewing, guidewire-based imaging system, an interventionalist could visualize the best path for advancing the guidewire to improve outcomes for patients with PAD.

Plaque modification in calcified chronic total occlusions: the PLACCTON study

Introduction and objectivesSevere calcification is present in> 50% of coronary chronic total occlusions (CTOs) undergoing percutaneous intervention. We aimed to describe the contemporary use and outcomes of plaque modification devices (PMDs) in this context. MethodsPatients were included in the prospective, consecutive Iberian CTO registry (32 centers in Spain and Portugal), from 2015 to 2020. Comparison was performed according to the use of PMDs. ResultsAmong 2235 patients, wire crossing was achieved in 1900 patients and PMDs were used in 134 patients (7%), requiring more than 1 PMD in 24 patients (1%). The selected PMDs were rotational atherectomy (35.1%), lithotripsy (5.2%), laser (11.2%), cutting/scoring balloons (27.6%), OPN balloons (2.9%), or a combination of PMDs (18%). PMDs were used in older patients, with greater cardiovascular burden, and higher Syntax and J-CTO scores. This greater complexity was associated with longer procedural time but similar total stent length (52 vs 57mm; P=.105). If the wire crossed, the procedural success rate was 87.2% but increased to 96.3% when PMDs were used (P=.001). Conversely, PMDs were not associated with a higher rate of procedural complications (3.7 vs 3.2%; P=.615). Despite the worse baseline profile, at 2 years of follow-up there were no differences in the survival rate (PMDs: 94.3% vs no-PMDs: 94.3%, respectively; P=.967). ConclusionsFollowing successful wire crossing in CTOs, PMDs were used in 7% of the lesions with an increased success rate. Mid-term outcomes were comparable despite their worse baseline profile, suggesting that broader use of PMDs in this setting might have potential technical and prognostic benefits.

Intravascular Lithotripsy for Calcium Modification in Chronic Total Occlusion Percutaneous Coronary Intervention.

Intravascular lithotripsy (IVL) has been shown to be safe and effective for calcium modification in nonocclusive coronary artery disease (CAD), but there are only case reports of its use in calcified chronic total occlusions (CTO). We report data from an international multicenter registry of IVL use during CTO percutaneous coronary intervention (PCI) and provide provisional data regarding its efficacy and safety. During the study period, IVL was used in 55 of 1053 (5.2%) CTO PCI procedures. IVL was used within the occluded segment after successful CTO crossing in 53 procedures and during incomplete CTO crossing in 2 cases. The mean J-CTO score was 3.1. CTO PCI technical and procedural success was achieved in 53 (96%) and 51 (93%) cases. Six patients had a procedural complication, with 3 main vessel perforations (5%). Two had covered stent implantation, one required pericardiocentesis, and one was managed conservatively. All had combination therapy with another calcium modification device. Two patients had a procedural myocardial infarction (PMI) (4%), and two others had a major adverse cardiovascular event (MACE) (4%) at a median follow-up of 13 (4–21) months. IVL can effectively facilitate calcium modification during CTO PCI. More data are required to establish the efficacy and safety of IVL and other calcium modification devices when used extraplaque or in combination during CTO PCI.

Endovascular revascularization of heavily calcified occlusion in superior mesenteric artery using Transcollateral approach

BackgroundMesenteric ischaemia is often a manifestation of severe vascular disease involving the superior mesenteric artery (SMA). Endovascular revascularization is challenging in a chronic total occlusion (CTO) of SMA.Case presentationA-73-year-old male patient was referred to our hospital because of a 2-year history of post prandial abdominal angina. Computed tomography (CT) images revealed a heavily calcified CTO in the ostium of SMA and three-dimensional CT (3D-CT) detected pancreaticoduodenal arcade with filling from the celiac artery. Then, endovascular procedure was attempted; however, angiography did not show the collateral route suitable for transcollateral approach. As demonstrated on the CT, we were successful in passing a guidewire through the SMA-CTO via the celiac trunk transcollateral route. After pull-through of the guidewire, two balloon-expandable stents were deployed in the ostium of SMA. During 3 months after stent implantation, the patient had no further episodes of abdominal angina on dual-anti-platelet therapy.ConclusionWe demonstrate a case of a heavily calcified SMA occlusion successfully treated with endovascular stenting employing a transcollateral approach, guided by 3D-CT.

Successful Peripheral Vascular Intervention in Patients with High-risk Comorbidities or Lesion Characteristics.

Certain comorbidities and lesion characteristics are associated with increased risk for procedural complications, limb events, and cardiovascular events following peripheral vascular intervention (PVI) in patients with peripheral arterial disease (PAD). The purpose of this review is to provide an overview of high-risk modifiable and unmodifiable patient characteristics and its relative impact on clinical outcomes such as amputation risk and mortality. Furthermore, general approaches to potentially mitigating these risks through pre-intervention planning and use of modern devices and techniques are discussed. Diabetes, tobacco use, and older age remain strong risk factors for the development of peripheral arterial disease. Recent data highlight the significant risk of polyvascular disease on major limb and cardiac events in advanced PAD, and ongoing studies are assessing this risk specifically after PVI. Challenging lesion characteristics such as calcified disease and chronic total occlusions can be successfully treated with PVI by utilizing novel devices (e.g., intravascular lithotripsy, re-entry devices) and techniques (e.g., subintimal arterial "flossing" with antegrade-retrograde intervention). Understanding high-risk patient comorbidities and lesion characteristics will improve our ability to counsel and manage patients with advanced PAD. Continued device innovation and novel techniques will aid in procedural planning for successful interventions to improve clinical outcomes.

Sharp recanalization of peripheral arterial chronic total occlusions.

Peripheral arterial chronic total occlusions (CTOs) usually have calcified caps at either ends. When attempting endovascular recanalization, these calcified CTO caps may prevent the interventionist in crossing the lesion with conventional catheter and guidewire techniques. Using specialized CTO devices or re-entry devices can help crossing the CTO, but such devices are usually expensive, not always readily available and require specialist training prior to usage."Sharp recanalization" is an alternative method of crossing the CTOs. If it is not possible to cross the CTO with conventional catheter and guidewire technique, one can take out the floppy end of the guidewire and use the stiff or the "sharp" end of the guidewire to break the hard CTO cap. Once the CTO cap is broken, the stiff end is replaced by the floppy end of the guidewire again to proceed with balloon angioplasty and/or stenting.In order to safely use the sharp recanalization technique while minimizing the risk of perforation, sharp recanalization should only be attempted once conventional methods have failed. The interventionist should plan sharp recanalization with the vascular path in mind and decide in advance how far s/he will proceed. It can be helpful to set a time limit together with the intervention team, past which the sharp recanalization attempt will be abandoned. Using straight catheters can help directing the stiff guidewire tip to the center of the vascular lumen and reduce the risk of sub intimal dissection or arterial wall perforation.

A calcified chronic total occlusion preclinical model.

To create an experimental chronic total occlusion (CTO) model with calcification by dietary modification (cholesterol, calcium carbonate, vitamin D) and local injection of pro-calcification factors (dipotassium phosphate, calcium chloride, and bone morphogenetic protein-2 [BMP-2]). Percutaneous revascularization of CTOs frequently fails in heavily calcified occlusions. Development of novel approaches requires a reproducible preclinical model of calcified CTO. CTOs were created in 18 femoral arteries of 9 New Zealand White rabbits using the thrombin injection model. Dietary interventions included a high cholesterol diet (0.5% or 0.25%), calcium carbonate (150 mg × 3-5 days/week), and vitamin D (50,000 U × 3-5 days/week). In selected animals, BMP-2 (1-4 μg), dipotassium phosphate, and calcium chloride were injected locally at the time of CTO creation. Animals were sacrificed at 2 weeks (n = 4 arteries), 6 weeks (n = 4 arteries), and 10-12 weeks (n = 14 arteries). CTOs showed evidence of chronic lipid feeding (foam cells) and chronic inflammation (intimal/medial fibrosis and microvessels, inflammatory cells, internal elastic lamina disruption). In calcium/vitamin D supplemented rabbits, mineralization (calcification and/or ossification) was evident as early as 2 weeks post CTO creation, and in 78% of the overall arteries. Mineralization changes were not present in the absence of calcium/vitamin D dietary supplements. Mineralization occurred in 85% of BMP-treated arteries and 60% of arteries without BMP. Complex mineralization occurs in preclinical CTO models with dietary supplementation of cholesterol with vitamin D and calcium.

TCTAP C-145 Rota Burr Incarceration (Entrapment) During Percutaneous Coronary Intervention for a Long, Calcified Chronic Total Occlusion of Right Coronary Artery

### Patient Initials or Identifier Number ABC ### Relevant Clinical History and Physical Exam A 63 years male, hypertensive, diabetic presented with chronic stable angina for 6 months. An echocardiogram was showing good left ventricular systolic function (EF-65%) and no regional wall motion

TCTAP C-188 Double Layer Stents Technique to Conquer the Severe Recoil Phenomenon After Recanalization of Severe Calcified Chronic Total Occlusion of Left Superficial Femoral Artery

TCTAP C-188 Double Layer Stents Technique to Conquer the Severe Recoil Phenomenon After Recanalization of Severe Calcified Chronic Total Occlusion of Left Superficial Femoral Artery

Percutaneous intentional intra-luminal-assisted recanalization (PILAR technique) of challenging chronic total occlusions using a high-frequency vibration device.

Recanalization of peripheral chronic total occlusions (CTO) is technically challenging especially in cases of in-stent and/or pre-stent and heavily calcified lesions. A high-frequency vibrational device (HFVD) was first used as a secondary-intention device in CTO recanalizations when they were refractory to a guidewire. The aim of this study was to assess the safety and efficacy of the HFVD as a first-line treatment for challenging CTOs and thus to define the percutaneous intentional intraluminal-assisted recanalization (PILAR) technique. Fifty-two patients were treated with the HFVD. Only challenging CTOs were included: 7 pre-stent, 7 in-stent, and 38 highly calcified CTOs. Technical success was defined as the ability to cross the CTO using the HFVD. Secondary outcome was defined as successful intraluminal crossing. Safety endpoints were procedure-related thromboembolism or perforation. Patients were followed up at 3 months and 1 year. The technical success rate for recanalization was 90%, of which 83% were intraluminal. The mean recanalized length was 91 ± 44 mm. One thromboembolic complication occurred, which was subsequently treated with thromboaspiration. Three-month and 1-year primary patency rates were 92% and 79%, respectively. HFVD-based PILAR is a safe and effective technique for in-stent or pre-stent CTO recanalization of long and calcified lesions. • Intraluminal recanalization is the preferred procedure in heavily calcified or pre-/in-stent CTO. • First-line use of assisted intraluminal recanalization for CTO defines the PILAR technique. • HFVD-based PILAR is safe and provides a high success rate for challenging CTO recanalization.

TCTAP C-085 The Stepwise Performing Percutaneous Coronary Intervention in Calcified Chronic Total Occlusion Lesion with Rich Collateral Using Simple Tool: Impossible or I'm Possible?

### Patient Initials or Identifier Number Mr. D. P ### Relevant Clinical History and Physical Exam A 47 years old male, came to the hospital with a chief complaint of chest pain while doing moderate activity. It relieved with sublingual nitrate. The symptom was on and off every day. Two years ago

Endovascular Crossing of Chronic Total Occlusions Using an Impulse: An Explorative Design Study

In this study we investigated whether exerting an impulse on a Chronic Total Occlusion (CTO) improves the success rate of CTO crossing as compared to the currently used method of statically pushing the guidewire against the CTO. A prototype (Ø2 mm) was developed that generates translational momentum using a spring-loaded indenter and converts it to an impulse during impact. Mechanical performance was evaluated by measuring the peak force and momentum for different spring compressions and strike distances in air and blood-mimicking fluid. Puncture performance, in terms of number of punctures, number of strikes to puncture, and energy transfer from the indenter to the CTO, was assessed for six tip shapes (stamp, wedge, spherical, pointed, hollow spherical, and ringed) on three CTO models with different weight percentages of gelatin and calcium. As a control, a Ø0.4 mm rigid rod was tested. A maximum indenter momentum of 1.3 mNs (velocity of 3.4 m/s), a peak force of 19.2 N (vs. 1.5 N reported in literature and 2.7 N for the control), and CTO displacement of 1.4 mm (vs. 2.7 mm for the control) were measured. The spherical and ringed tips were most effective, with on average 2.3 strikes to puncture the most calcified CTO model. The prototype generated sufficient peak forces to puncture highly calcified CTO models, which are considered most difficult to cross during PCI. Furthermore, CTO displacement was minimized, resulting in a more effective procedure. In future, a smaller, faster, and flexible clinical prototype will be developed.

Impact of Calcium on Chronic Total Occlusion Percutaneous Coronary Interventions

We sought to examine the impact of calcific deposits on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The outcomes of 1,476 consecutive CTO PCIs performed in 1,453 patients (65.5 ± 10years, 85% male) between 2012 and 2016 at 11 US centers were evaluated. Moderate or severe quantity of calcium was present in 58% of target lesions. Calcified lesions were more tortuous and more likely to have proximal cap ambiguity and interventional collaterals. PCI of moderately/severely calcified CTOs more often required use of the retrograde approach (54% vs 30%, p <0.001) and was associated with longer procedure and fluoroscopy time and higher air kerma radiation dose and contrast volume. Moderate/severe quantity of calcium was associated with lower technical (86.6% vs 93.8%, p <0.001) and procedural (84.4% vs 92.7%, p <0.001) success rates and higher incidence of major adverse cardiac events (3.7% vs 1.8%, p=0.033). On multivariate analysis, the presence of moderate/severe quantity of calcium was not independently associated with technical success. Balloon angioplasty was the most common lesion preparation technique for calcified lesions, followed by rotational atherectomy and laser. To conclude, in a contemporary, multicenter registry, moderate/severe calcific deposits were present in 58% of attempted CTO lesions and were associated with higher use of the retrograde approach, lower success, and higher complication rates. However, on multivariable analysis, the amount of calcium was not independently associated with technical success.