Evaluation of acute and midterm outcomes after complex combined antegrade/retrograde recanalization for occlusions of the femoropopliteal and infrapopliteal arteries.

BACKGROUND: When antegrade recanalization of femoropopliteal and/or infrapopliteal occlusions fails, retrograde access has become an established option. To evaluate the results of combined antegrade and retrograde recanalization of femoropopliteal and infrapopliteal occlusions, patients undergoing secondary retrograde recanalization attempts were analyzed retrospectively. METHODS: The primary end point was the success of the procedure (successful occlusion crossing using the antegrade/retrograde technique). Secondary end points include complication rate, primary patency and target lesion revascularization (TLR) rate, amputation rate, changes in ankle-brachial index, and Rutherford-Becker class. Predictors for procedure failure and TLR were analyzed. RESULTS: We included 888 patients: 362 with femoropopliteal (group 1), 353 with infrapopliteal (group 2), and 173 with multilevel (group 3) recanalization. Critical limb-threatening ischemia was present in group 1, 2, and 3 in 36%, 62%, and 76% of patients, respectively. The intervention was successful in 92.5%, 93.8%, and 90.8% of the respective cases (P = .455). The overall peri-interventional complication rate was 7.2%. At 6, 12, and 24 months, primary patency was highest in group 1 (63.9%, 45.8%, and 33.3%), followed by group 3 (59.8%, 46.1%, and 33.3%), and group 2 (58.5%, 43.1%, and 30.4%; P = .537). The risk of undergoing repeated TLR within 24 months was 31.4% for group 1, 39.1% for group 2, and 45.7% for group 3. At 24 months, the survival rates in groups 1, 2, and 3 were 93.8%, 79.4%, and 87.5%, respectively. Over 24 months, 75 patients (8.4%) had to undergo amputation. Significant improvements in both ankle-brachial index and Rutherford-Becker class were present at discharge as well as at 6, 12, and 24 months (P < .001). Dialysis dependency was a predictor of unsuccessful antegrade/retrograde recanalization (P = .048). Lesion length (P = .0043), dialysis (P = .033), and recanalization level (P = .013) increase the risk of TLR. CONCLUSIONS: Using a combined antegrade/retrograde access, recanalization of occluded femoropopliteal and/or infrapopliteal arteries can be achieved in a large number of cases. Owing to the high rate of repeated TLR across all lesion localizations, the indication for antegrade and retrograde recanalization may be limited to patients with critical limb-threatening ischemia.

DETOUR2 trial outcomes demonstrate clinical utility of percutaneous transmural bypass for the treatment of long segment, complex femoropopliteal disease.

OBJECTIVE: Percutaneous transmural arterial bypass (PTAB) using the DETOUR system aims to create a percutaneous, endovascular femoropopliteal bypass for the treatment of long segment, complex superficial femoral and proximal popliteal artery disease. The goal of the DETOUR2 study is to investigate the safety and effectiveness of the therapy in comparison with pre-established performance goals. METHODS: The DETOUR2 investigational device exemption study is a prospective, single-arm, multicenter, international trial of symptomatic peripheral arterial disease patients (Rutherford classes 3-5) undergoing the DETOUR procedure for long segment (>20 cm) superficial femoral artery disease. Prespecified end points included primary safety (composite of major adverse events) at 30 days, and effectiveness (primary patency defined as freedom from restenosis or clinically driven target lesion revascularization) at 1 year. RESULTS: We enrolled 202 patients at 32 sites with 200 treated with the DETOUR system. The mean lesion length was 32.7 cm, of which 96% were chronic total occlusions (CTO) and 70% were severely calcified. Technical success was achieved in 100% of treated patients. The primary safety end point was met with a 30-day freedom from major adverse event rate of 93.0%. The 1-year primary effectiveness end point was met with 72.1% primary patency at 12 months. Primary-assisted and secondary patency were 77.7% and 89.0%, respectively, at 12 months. The 12 month deep venous thrombosis incidence was 4.1% with no pulmonary emboli reported. Venous quality-of-life scores showed no significant changes from baseline. There was a Rutherford improvement of at least one class through 12 months in 97.2% of patients. The mean ankle-brachial index also improved from 0.61 to 0.95 during this period. There were marked improvements in quality-of-life and functional status measures. CONCLUSIONS: The DETOUR2 study met both the primary safety and effectiveness end points, demonstrating clinical usefulness of this novel therapeutic strategy in long femoropopliteal lesions.

Efficacy of revascularization in CTO patients based on hibernating myocardium therapy.

BACKGROUND: The effectiveness of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is still uncertain, especially for patients with ischemic left ventricular dysfunction. This study aimed to assess hibernating myocardium (HM), as determined by single-photon emission computed tomography (SPECT) and 18F-FDG positron emission tomography (PET), and to compare the benefits of PCI and optimal medical therapy (OMT). METHODS: A retrospective study collected data from 332 patients with CTO and ischemic left ventricular dysfunction. The study compared patients who underwent PCI or OMT via propensity score matching (PSM) analysis which was performed with a 1:2 matching protocol using the nearest neighbour matching algorithm. The primary endpoint of the study was the occurrence of major adverse cardiac events (MACE), defined as a composite of cardiac death, readmission for worsening heart failure (WHF), revascularization and myocardial infarction (MI). RESULTS: After PSM, there were a total of 246 individuals in the PCI and OMT groups. Following Cox regression, hibernating myocardium/total perfusion defect (HM/TPD) was identified as an independent risk factor (hazard ratio (HR): 1.03, 95% confidence interval (CI): 1.008-1.052, p = .007). The cut-off value of HM/TPD was 38%. The results of the subgroup analysis suggest that for patients with HM/TPD >38%, the OMT group had a greater risk of MACE (p = .035). A sensitivity analysis restricting patients with single-vessel CTO lesions, HM/TPD remained an independent predictor (HR 1.025, 95% CI 1.008-1.043, p = .005). CONCLUSION: HM/TPD is an independent predictor of MACE, and for patients with HM/TPD > 38%, CTO-PCI had a lower risk of MACE compared with OMT. However, further validation is still needed through large-scale studies.

International survey of chronic total occlusion percutaneous coronary intervention operators.

BACKGROUND: Contemporary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) practice has received limited study. AIM: To examine the contemporary CTO PCI practice. METHODS: We performed an online, anonymous, international survey of CTO PCI operators. RESULTS: Five hundred forty-five CTO PCI operators and 190 interventional cardiology fellows with an interest in CTO PCI participated in this survey. Almost half were from the United States (41%), most (93%) were men, and the median h/week spent in the hospital was 58. Median annual case numbers were 205 (150-328) for PCIs and 20 (5-50) for CTO PCIs. Almost one-fifth (17%) entered CTO cases into registries, such as PROGRESS-CTO (55%) and EuroCTO (20%). More than one-third worked at academic institutions (39%), 31% trained dedicated CTO fellows, and 22% proctored CTO PCI. One-third (34%) had dedicated CTO PCI days. Most (51%) never discharged CTO patients the same day, while 17% discharged CTO patients the same day >50% of the time. After successful guidewire crossing, 38% used intravascular imaging >90% of the time. Most used CTO scores including J-CTO (81%), PROGRESS-CTO (35%), and PROGRESS-CTO complications scores (30%). Coronary artery perforation was encountered within the last month by 19%. On a scale of 0-10, the median comfort levels in treating coronary artery perforation were: covered stents 8.8 (7.0-10), coil embolization 5.0 (2.1-8.5), and fat embolization 3.7 (0.6-7.3). Most (51%) participants had a complication cart/kit and 25% conducted regular complication drills with catheterization laboratory staff. CONCLUSION: Contemporary CTO PCI practices vary widely. Further research on barriers to following the guiding principles of CTO PCI may improve patient outcomes.

Applicability of J-CTO channel score to predict microcatheter tracking during retrograde percutaneous coronary intervention of chronic total occlusions: Insights from the SURFING MICRO registry.

BACKGROUND: The J-chronic total occlusion (CTO) channel score can predict guidewire tracking of the collateral channels (CCs), but its efficacy in predicting microcatheter tracking has never been tested in the setting of retrograde CTO-percutaneous coronary intervention (PCI). AIMS: Predicting microcatheter collateral tracking during retrograde CTO-PCIs. METHODS: A total of 189 patients undergoing retrograde CTO-PCI from April 2017 to August 2021 were screened. The primary outcome of interest was a correlation between J-CTO channel score and microcatheter tracking failure (MTF) after successful CC tracking by the guidewire. The independent association between anatomical features of the J-CTO channel score and the primary outcome of interest was explored. RESULTS: After adjustment, only small size (adjusted OR: 12.70, 95% confidence interval [CI]: 1.79-89.82; p = 0.01) and continuous bends (adjusted OR: 14.15, 95% CI: 2.77-72.34; p < 0.001) remained significantly associated with an increased risk of MTF for septal collaterals. The small size was the only predictor of the MTF for epicardial collaterals (OR: 6.39, 95% CI: 1.13-35.96; p = 0.020) at univariate analysis. Patients in the MTF group had a lower incidence of procedural success compared with patients in the microcatheter tracking success (MTS) group (40.0% vs. 93.9%, p < 0.001) and had a higher incidence of collateral perforations (20.0% vs. 3.0%, p < 0.001). CONCLUSION: Small and tortuous septal collaterals, identified by a score ≥3, are associated with an increased risk of MTF, lower incidence of procedural success, and higher risk of procedural complications driven by collateral perforations.

Intravascular ultrasound-guided STAR 2.0: A new technique for chronic total occlusion recanalization.

The use of the subintimal space has allowed a massive advancement in the field of chronic total occlusion percutaneous coronary intervention (PCI). The STAR technique is the first of subintimal techniques. Despite a high acute success rate, follow-up results showed unfavorable outcomes with half of the treated patients showing restenosis/reocclusion at 6 months. We present three cases in which a modification of the STAR technique guided by intravascular ultrasound (IVUS), namely the STAR 2.0, was used as a bailout for successful PCI of chronic total occlusions.

Management of iatrogenic ascending aortic dissection after percutaneous intervention of chronic total occlusion.

BACKGROUND: This study highlights the prevalence and conservative management strategies of iatrogenic ascending aortic dissection after percutaneous intervention (PCI) of chronic total occlusion (CTO). METHODS: Retrospective analysis on patients who underwent CTO PCI from one medical center from 2020 to 2022 was performed by two operators. Data was obtained from the Prospective Global Registry for the Study of CTO database. RESULTS: Out of 318 patients, there were six reported cases of iatrogenic ascending aortic dissection. The causes of dissection included guiding catheter trauma, antegrade injection, two retrograde injection, and two cases of balloon rupture after lithotripsy. IVUS-guided stenting of the coronary back to the origin to seal the entry of the dissection flap occurred in two patients. All patients had a conservative management approach. No patient had to undergo urgent surgery. CONCLUSION: While the incidence remains rare, complications, including aortic dissection, are more frequent in CTO PCI as compared to non-CTO PCI. IVUS can be used to complete coronary intervention so long as the patient remains clinically and hemodynamically stable. Patients should have formal imaging with either transesophageal echocardiogram or computed tomography angiography. The outcomes of patients who experience iatrogenic aortic dissection during CTO PCI with stable coronary disease seem to be better than in patients with acute coronary syndrome.

Intravascular lithotripsy in heavily calcified chronic total occlusion: procedural and one-year clinical outcomes.

BACKGROUND: Calcification within chronic total occlusions (CTO) is strongly associated with worse outcomes. Despite the excellent success and safety of intravascular lithotripsy (IVL) in heavily calcified lesions, evidence in CTO remains scarce. AIM: This study aimed to evaluate the procedural and long-term clinical outcomes of IVL in heavily calcified CTO. METHODS: Patients who underwent IVL between 2019 and 2024 from an ongoing prospective multicenter registry were eligible for inclusion. Patients were therefore classified in CTO and non-CTO groups. The efficacy and safety endpoints of CTO percutaneous coronary interventions were defined according to the CTO-ARC consensus. In-hospital major adverse cardiovascular events (MACE) included cardiac death, nonfatal myocardial infarction and target lesion revascularization (TVR). RESULTS: A total of 404 patients underwent IVL, of which the treated lesion was a CTO in 33 (8.2%). The mean J-CTO score was 2.3 ± 1.1. Device success showed no significant difference between CTO and non-CTO groups (100% vs 98.4%; p = 0.35). Comparable technical success with residual stenosis <30% was observed in both groups (90.1% in CTO vs 89.2% in non-CTO, p = 0.83). The incidence of MACE was similar across groups during hospital stays (CTO 6.0% vs. non-CTO 1.9%, p = 0.12), at 30-day (CTO 9.1% vs. non-CTO 3.0%, p = 0.07), and at 12-month follow-up (CTO 9.1% vs. non-CTO 7.3%, p = 0.70). CONCLUSION: IVL provides high procedural success and consistent clinical outcomes in both CTO and non-CTO cases, reinforcing its role in managing heavily calcified coronary lesions.

Manual Microcatheter-tip Modification: A bailout option for difficult "tip-in" technique during chronic total occlusion percutaneous coronary intervention.

The retrograde approach in chronic total occlusion (CTO) interventions often encounters significant challenges, particularly, when aligning the retrograde microcatheter (MC) with the antegrade system is difficult, complicating or even preventing standard externalization. To address these issues, techniques like the "tip-in" have proven to be effective backup strategies. We introduce the "Manual Microcatheter-tip Modification" (MMM) technique as an alternative when the "tip-in" method faces complications. We present a case of a left anterior descending CTO where MMM was successfully employed for the first time, enabling successful revascularization by manually modifying the MC tip to engage the retrograde guidewire. We explore the technical details within the framework of contemporary CTO PCI. This new technique could enhance the management of CTO interventions, offering innovative solutions when traditional externalization methods are problematic.

Challenges in the diagnosis and management of dry tamponade.

Dry tamponade is a rare complication of percutaneous coronary intervention. It encompasses a heterogenous pathophysiology and is used to describe hemodynamic compromise secondary to a coronary artery perforation, without free-flowing fluid in the pericardium. Tamponade physiology can result from compressive epicardial, intramyocardial, subepicardial hematomas, or dissecting intramyocardial hematomas. The diagnosis of dry tamponade requires hemodynamic derangement in the context of a compressive hematoma as demonstrated by imaging. Although echocardiography can often help identify dry tamponade, additional studies including right heart catheterization, computed tomography, or cardiac magnetic resonance imaging can inform the exact mechanism and help guide management. This article describes a case of dry tamponade, reviews the existing literature on the topic, and offers expert recommendations on diagnosis and management.

Safety and feasibility of rotational atherectomy (RA) versus conventional stenting in patients with chronic total occlusion (CTO) lesions: a systematic review and meta-analysis.

BACKGROUND AND AIM: Interventional cardiologists face challenges in managing chronic total occlusion (CTO) lesions, with conflicting results when comparing rotational atherectomy (RA) to conventional PCI. This meta-analysis aims to provide a critical evaluation of the safety and feasibility of RA in CTO lesions. METHODS: PubMed, Scopus, Web of Science, Ovid, and Cochrane central library until April 2023 were searched for relevant studies. MACE was our primary outcomes, other outcomes were all cause of death, cardiac death, MI, and TVR. Also, we reported angiographic outcomes as technical success, procedural success, and procedural complications in a random effect model. The pooled data was analyzed using odds ratio (OR) with its 95% CI using STATA 17 MP. RESULTS: Seven studies comprising 5494 patients with a mean follow-up of 43.1 months were included in this meta-analysis. Our pooled analysis showed that RA was comparable to PCI to decrease the incidence of MACE (OR = 0.98, 95% CI [0.74 to 1.3], p = 0.9). Moreover, there was no significant difference between RA and conventional PCI in terms of other clinical or angiographic outcomes. CONCLUSION: Our study showed that RA had comparable clinical and angiographic outcomes as conventional PCI in CTO lesions, which offer interventional cardiologists an expanded perspective when addressing calcified lesions. PROSPERO REGISTRATION: CRD42023417362.

The perspectives of Maori on community treatment orders: A thematic analysis.

AIM: To understand the themes for Maori subjected to compulsory community treatment orders. BACKGROUND: The Mental Health (Compulsory Assessment and Treatment) Act 1992 has been utilised in Aotearoa New Zealand for more than three decades. Despite Maori having higher rates of being subject to community treatment orders, there is little research examining their perspectives of its benefits and harms. METHODS: Thematic analysis of a purposive sample of Maori in Hawke's Bay, New Zealand. RESULTS: Five themes were developed. Maori described community treatment orders as restrictive and stigmatising. Some Maori described being poorly informed of the structures surrounding the use of community treatment orders and saw it as a mechanism to circumvent information-giving regarding treatment. Counterbalancing these, Maori described community treatment orders as mandating support and saw them as a mechanism to access care. Finally, some described their compulsory treatment status as unimportant and irrelevant. CONCLUSIONS: Thematic analysis identified five clear themes from interview participants. Conceptualisation of community treatment orders was largely negative, although Maori acknowledged that being subject to community treatment orders demanded more support from services. Themes of stigma and restriction are common in the literature, however, conception of the use of community treatment orders to bypass consent is novel. The literature describes community treatment orders as providing support, however, in this study, the interpretation suggests a need to lose personal autonomy to receive care, a potentially 'slippery slope' towards a two-tier type service. These findings remind services of the importance of attending to cultural elements of care, being clear around the process of consent. In terms of policy, weaving in cultural understanding appears to be important from an Indigenous perspective.

Coronary steal: how many thieves are out there?

The colorful term "coronary steal" arose in 1967 to parallel "subclavian steal" coined in an anonymous 1961 editorial. In both instances, the word "steal" described flow reversal in the setting of an interconnected but abnormal vascular network-in one case a left subclavian stenosis proximal to the origin of the vertebral artery and in the other case a coronary fistula. Over time, the term has morphed to include a larger set of pathophysiology without explicit flow reversal but rather with a decrease in stress flow due to other mechanisms. This review aims to shed light on this phenomenon from a clinical and a pathophysiological perspective, detailing the anatomical and physiological conditions that allow so-called steal to appear and offering treatment options for six distinct scenarios.

Chronic Total Occlusions: A State-of-the-Art Review.

The percutaneous management of chronic total occlusions (CTO) is a well-established sub-specialty of Interventional Cardiology, requiring specialist equipment, training, and techniques. The heterogeneity of approaches in CTO has led to the generation of multiple algorithms to guide operators in their management. The evidence base for management of CTOs has suffered from inconsistent descriptive and quantitative terminology in defining the nature of lesions and techniques utilised, as well as seemingly contradictory data about improvement in ventricular function, symptoms of angina, and mortality from large-scale registries and randomised controlled trials. Through this review, we explore the history of CTO management and its supporting evidence in detail, with an outline of limitations of CTO-percutaneous coronary intervention and a look at the future of this growing field within cardiology.

Naturalistic outcomes of patients discharged from a community treatment order: QA project.

OBJECTIVE: To study outcomes for patients after they are discharged from Community treatment orders (CTO) including rate of relapse, median time to relapse and to identify the risk factors associated with relapse. METHOD: The study population included patients discharged from CTO from July 2017 to December 2021, managed by a major metropolitan* case management team (CMT). The data were collected from electronic medical records (EMR). Descriptive analysis was conducted to study the sample characteristics. Logistic regression using univariate and multivariate analysis was performed to examine the associations between factors related to relapse. RESULTS: A total of 128 patients were studied. The relapse rate was 27.4% with median time to relapse of 72 days. Poor insight, poor treatment compliance, duration of CTO and number of CMT contacts were significantly associated with relapse while substance use, psychiatric comorbidities and psychosocial factors were not. CONCLUSIONS: The findings suggest that people who relapsed had poor insight and poor medication adherence, had CTO for a longer period and had frequent contact from CMT even after discharge from CTO.

Heart Failure-Related Outcomes in Patients with Left Ventricular Dysfunction Undergoing Percutaneous Chronic Total Occlusion Revascularization.

Background: The presence of a chronic total occlusion (CTO) and severe left ventricular (LV) systolic dysfunction are known negative prognostic factors in patients with coronary artery disease. Several studies have examined the effect of CTO revascularization on mortality, symptoms, occurrence of myocardial infarction (MI), and cardiac function in patients with normal or reduced LV function. However, the effect of CTO revascularization on heart failure-related events in patients with LV dysfunction, such as heart failure hospitalization (HFH), the occurrence of atrial fibrillation (AF), and a worsening renal function (WRF), has not yet been evaluated. To assess the success rate and safety of CTO percutaneous coronary interventions (PCIs) in coronary patients with LV ejection fractions of ≤ 40% and evaluate the impact of successful CTO revascularization on HFH, occurrence of AF, and WRF. Methods: Prospectively, data were collected from CTO PCIs performed at three referral centers and analyzed. From a total of 1435 CTO PCIs, 132 (9.2%) patients with a left ventricular ejection fraction (LVEF) of ≤ 40% were included in this analysis. The median follow-up duration was 23.18 months (interquartile range (IQR): 11.02-46.66 months). Results: A successful CTO PCI was achieved in 109 of these patients, while the procedure was unsuccessful in 23 patients (82.5% procedural success rate). Overall, the intervention had an acceptable number of peri-procedural (or in-hospital) complications (9.1%). During the follow-up period, the rates of all-cause death, cardiovascular death, and non-fatal MI were not significantly different between the two groups. The rates of HFH were significantly lower in the successful PCI group, while WRF and AF did not differ between successful and unsuccessful PCI groups. Successful PCI and higher estimated glomerular filtration rate (eGFR) were independent predictors of a lower risk of HFH, while prior stroke and diabetes were independent predictors of a higher risk of HFH. Conclusions: In patients with reduced LV systolic function (ejection fraction, EF ≤ 40%), CTO PCI is a safe and effective procedure and successful CTO PCI is independently associated with a lower risk of HFH during follow-up. Further expansion of this cohort is necessary to confirm these results.

Electrocautery-assisted re-entry to resolve bilateral aorto-ostial chronic total occlusions due to leaflet obstruction following transcatheter aortic valve replacement.

Coronary artery obstruction is a rare but life-threatening complication of transcatheter aortic valve replacement (TAVR). While urgent percutaneous coronary intervention has been described in cases of acute occlusion, little is known about the interventional management of obstruction once it has occurred in the chronic setting. We describe a case in which electrocautery-assisted re-entry was successfully utilized to manage the right coronary artery and left main chronic total occlusion due to leaflet-induced coronary artery obstruction after TAVR.

Stingray CART (K14 technique): A novel antegrade dissection reentry strategy.

A novel device based CART technique (K14 technique) has been described with 2 case examples to illustrate the same. This CART has been performed after ADR and Reverse-CART were unsuccessful.

The impact of chronic total occlusions in patients undergoing transcatheter aortic valve replacement: A systematic review and meta-analysis.

Coronary artery disease (CAD) is frequently encountered in patients evaluated for transcatheter aortic valve replacement (TAVR) due to severe aortic stenosis. The prognostic relevance of chronic total occlusions (CTOs) in this setting is poorly understood. We conducted a search of MEDLINE and EMBASE to identify studies evaluating patients who underwent TAVR and evaluated outcomes depending on the presence of coronary CTOs. Pooled analysis was performed to estimate the rate and risk ratio for mortality. Four studies involving 25,432 patients fulfilled the inclusion criteria. The follow up ranged from in-hospital outcomes to 8-years follow-up. Coronary artery disease was present in 67.8% to 75.5% of patients in 3 studies which reported this variable. The prevalence of CTOs varied between 2% and 12.6% in this cohort. The presence of CTOs was associated with increase in length of stay (8.1 ± 8.2 vs. 5.9 ± 6.5, p < 0.01), cardiogenic shock (5.1% vs. 1.7%, p < 0.01), acute myocardial infarction (5.8% vs. 2.8%, p = 0.02) and acute kidney injury (18.6% vs. 13.9%, p = 0.048). The pooled 1-year death rate revealed 41 deaths in 165 patients in the CTO group and 396 deaths in 1663 patients with no CTO ((24.8%) vs. (23.8%)). The meta-analysis of death with CTO versus no CTO showed a nonsignificant trend toward increased mortality with CTOs (risk ratio 1.11 95% CI 0.90-1.40, I2 = 0%). Our analysis suggests that concomitant CTO lesions in patients undergoing TAVR are common, and its presence was associated with increased in-hospital complications. However, CTO presence by itself was not associated with increased long-term mortality, only a nonsignificant trend toward an increased risk of death in patients with CTO was found. Further studies are warranted to assess the prognostic relevance of CTO lesion in TAVR patients.

Effectiveness, safety, and patient reported outcomes of a planned investment procedure in higher-risk chronic total occlusion percutaneous coronary intervention: Rationale and design of the invest-CTO study.

BACKGROUND: The anatomical complexity of a chronic total occlusion (CTO) correlates with procedural failure and complication rates. CTO modification after unsuccessful crossing has been associated with subsequent higher technical success rates, but complication rates remain high with this approach. While successful CTO percutaneous coronary intervention (PCI) has been associated with improved angina and quality of life (QOL) this has not been demonstrated in anatomically high-risk CTOs. Whether a planned CTO modification procedure, hereafter named Investment procedure, could improve patient outcomes has never been investigated. STUDY DESIGN: Invest-CTO is a prospective, single-arm, international, multicenter study, evaluating the effectiveness and safety of a planned investment procedure, with a subsequent completion CTO PCI (at 8-12 weeks), in anatomically high-risk CTOs. We will enroll 200 patients with CTOs defined as high-risk according to our Invest CTO criteria at centers in Norway and United Kingdom. Patients with aorto-ostial lesions, occlusion within a previous stent, or a prior attempt at target vessel CTO PCI within 6 months will be excluded. The co-primary endpoints are cumulative procedural success (%) after both procedures, and a composite safety endpoint at 30 days after completion CTO PCI. Patient reported outcomes (PROs), treatment satisfaction, and clinical endpoints will be reported. CONCLUSION: This study will prospectively evaluate the effectiveness and safety of a planned two staged PCI procedure in the treatment of high-risk CTOs and may have the potential to change current clinical practice.