Role of the retrograde Carlino technique for chronic total occlusion percutaneous coronary intervention.

BACKGROUND: There is scarce data on the outcomes of the Carlino technique for chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We aimed to investigate the indications and outcomes of the Carlino technique as performed in the context of the retrograde approach. METHODS: We pooled CTO PCI cases where a retrograde Carlino technique was performed from high-volume operators at four centers. The Carlino technique was characterized according to its indication (achieving plaque/cap modification, clarifying microcatheter location within the vessel, resolving distal cap ambiguity) and was considered successful when it led to the desired outcome. RESULTS: A total of 43 patients were included. Occlusion complexity was very high (mean J-CTO score 3.3 ± 0.8). The two most common indications were understanding the anatomy of the occlusion and clarifying gear location (37.2%) and impenetrable distal cap (34.9%). The Carlino technique was successful in 88.4% of cases. Overall technical and procedural success was 86.0%. The most common successful crossing technique was reverse controlled antegrade and retrograde subintimal tracking (70.3%). No complications were attributed to the Carlino technique. CONCLUSIONS: We observed a high success rate of the retrograde Carlino technique, as well as overall technical and procedural success rates. No Carlino technique-related complications were observed. Additional data from larger registries are warranted to further confirm the safety and efficacy of this technique.

STAR procedure becomes SAFER: First-in-man case series of a new antegrade dissection re-entry technique.

INTRODUCTION: Antegrade dissection and re-entry (ADR) is an integral part of the hybrid algorithm, which has allowed for improved outcomes in chronic total occlusion (CTO) coronary intervention (PCI). METHODS: A new ADR method, Subintimal Antegrade FEnestration and Re-entry (SAFER), is described. The results of a first-in-man series are presented. RESULTS: SAFER was performed on seven consecutive patients with angiographic and clinical success in all patients. CONCLUSIONS: This first-in-man study has shown that the SAFER technique is feasible and effective with the possibility of improving the antegrade PCI CTO success rate.

Wire-based antegrade dissection re-entry technique for coronary chronic total occlusions percutaneous revascularization: Experience from the ERCTO Registry.

BACKGROUND: The recent development and widespread adoption of antegrade dissection re-entry (ADR) techniques have been underlined as one of the antegrade strategies in all worldwide CTO consensus documents. However, historical wire-based ADR experience has suffered from disappointing long-term outcomes. AIMS: Compare technical success, procedural success, and long-term outcome of patients who underwent wire-based ADR technique versus antegrade wiring (AW). METHODS: One thousand seven hundred and ten patients, from the prospective European Registry of Chronic Total Occlusions (ERCTO), underwent 1806 CTO procedures between January 2018 and December 2021, at 13 high-volume ADR centers. Among all 1806 lesions attempted by the antegrade approach, 72% were approached with AW techniques and 28% with wire-based ADR techniques. RESULTS: Technical and procedural success rates were lower in wire-based ADR than in AW (90.3% vs. 96.4%, p < 0.001; 87.7% vs. 95.4%, p < 0.001, respectively); however, wire-based ADR was used successfully more often in complex lesions as compared to AW (p = 0.017). Wire-based ADR was used in most cases (85%) after failure of AW or retrograde procedures. At a mean clinical follow-up of 21 ± 15 months, major adverse cardiac and cerebrovascular events (MACCEs) did not differ between AW and wire-based ADR (12% vs. 15.1%, p = 0.106); both AW and wire-based ADR procedures were associated with significant symptom improvements. CONCLUSIONS: As compared to AW, wire-based ADR is a reliable and effective strategy successfully used in more complex lesions and often after the failure of other techniques. At long-term follow-up, patient's MACCEs and symptoms improvement were similar in both antegrade techniques.

Gender differences in percutaneous coronary intervention for chronic total occlusions from the ERCTO study.

BACKGROUND: Gender-specific data addressing percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) in female patients are scarce and based on small sample size studies. AIMS: We aimed to analyze gender-differences regarding in-hospital clinical outcomes after CTO-PCI. METHODS: Data from 35,449 patients enrolled in the prospective European Registry of CTOs were analyzed. The primary outcome was the comparison of procedural success rate in the two cohorts (women vs. men), defined as a final residual stenosis less than 20%, with Thrombolysis In Myocardial Infarction grade flow = 3. In-hospital major adverse cardiac and cerebrovascular events (MACCEs) and procedural complications were deemed secondary outcomes. RESULTS: Women represented 15.2% of the entire study population. They were older and more likely to have hypertension, diabetes, and renal failure, with an overall lower J-CTO score. Women showed a higher procedural success rate (adjusted OR [aOR] = 1.115, confidence interval [CI]: 1.011-1.230, p = 0.030). Apart from previous myocardial infarction and surgical revascularization, no other significant gender differences were found among predictors of procedural success. Antegrade approach with true-to-true lumen techniques was more commonly used than retrograde approach in females. No gender differences were found regarding in-hospital MACCEs (0.9% vs. 0.9%, p = 0.766), although a higher rate of procedural complications was observed in women, such as coronary perforation (3.7% vs. 2.9%, p < 0.001) and vascular complications (1.0% vs. 0.6%, p < 0.001). CONCLUSIONS: Women are understudied in contemporary CTO-PCI practice. Female sex is associated with higher procedural success after CTO-PCI, yet no sex differences were found in terms of in-hospital MACCEs. Female sex was associated with a higher rate of procedural complications.

External validation of the PROGRESS-CTO perforation risk score: Individual patient data pooled analysis of three registries.

BACKGROUND: Coronary artery perforation is one of the most feared and common complications of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: To assess the usefulness of the recently developed PROGRESS-CTO (NCT02061436) perforation risk score in independent cohorts. Individual patient-level data pooled analysis of three registries was performed. RESULTS: Of the 4566 patients who underwent CTO PCI at 25 centers, 196 (4.2%) had coronary artery perforation. Patients with perforations were older (69 ± 10 vs. 65 ± 10, p < 0.001), more likely to be women (19% vs. 13%, p = 0.009), more likely to have a history of prior coronary artery bypass graft (34% vs. 20%, p < 0.001), and unfavorable angiographic characteristics such as blunt stump (62% vs. 48%, p < 0.001), proximal cap ambiguity (52% vs. 34%, p < 0.001), and moderate-severe calcification (60% vs. 49%, p = 0.002). Technical success was lower in patients with perforations (73% vs. 88%, p < 0.001). The area under the receiver operating characteristic curve of the PROGRESS-CTO perforation risk model was 0.76 (95% confidence interval [CI], 0.72-0.79), with good calibration (Hosmer-Lemeshow p = 0.97). We found that the CTO PCI perforation risk increased with higher PROGRESS-CTO perforation scores: 0.3% (score 0), 2.3% (score 1), 3.1% (score 2), 5.5% (score 3), 7.5% (score 4), 14.6% (score 5). CONCLUSION: Given the good discriminative performance, calibration, and the ease of calculation, the PROGRESS-CTO perforation score may facilitate assessment of the risk of perforation in patients undergoing CTO PCI.

The origin of the popular iconic heart symbol: fiction or facts?

The heart is generally perceived as the core of emotion, affection, and love. Its universally accepted iconic representation is everywhere these sentiments have to be depicted. However, the question is: where does the popular heart shape comes from? In fact, it is difficult to relate this symbol to the real heart shape. With possible early examples or direct predecessors in the 13th to 14th century, the familiar symbol of the heart representing love developed in the 15th century, and became popular in Europe during the 16th. While performing several coronary total occlusion recanalization procedures, it has become excitingly evident that, during contemporaneous dual injections of both right and left coronary arteries, the iconic shadow of the heart can be effectively observed. The possibility that the evidence of this cardiac shape could already be visible to the eyes of people living at the time of the first iconic appearances of the heart image is difficult to surmise. How could our ancestors connect the iconic form to the real heart shape? In the present article, we discuss how this iconic shape could have been derived from anatomical observations made in the ancient world.

Definitions and Clinical Trial Design Principles for Coronary Artery Chronic Total Occlusion Therapies: CTO-ARC Consensus Recommendations.

Over the past 2 decades, chronic total occlusion (CTO) percutaneous coronary intervention has developed into its own subspecialty of interventional cardiology. Dedicated terminology, techniques, devices, courses, and training programs have enabled progressive advancements. However, only a few randomized trials have been performed to evaluate the safety and efficacy of CTO percutaneous coronary intervention. Moreover, several published observational studies have shown conflicting data. Part of the paucity of clinical data stems from the fact that prior studies have been suboptimally designed and performed. The absence of standardized end points and the discrepancy in definitions also prevent consistency and uniform interpretability of reported results in CTO intervention. To standardize the field, we therefore assembled a broad consortium comprising academicians, practicing physicians, researchers, medical society representatives, and regulators (US Food and Drug Administration) to develop methods, end points, biomarkers, parameters, data, materials, processes, procedures, evaluations, tools, and techniques for CTO interventions. This article summarizes the effort and is organized into 3 sections: key elements and procedural definitions, end point definitions, and clinical trial design principles. The Chronic Total Occlusion Academic Research Consortium is a first step toward improved comparability and interpretability of study results, supplying an increasingly growing body of CTO percutaneous coronary intervention evidence.

A new combined antegrade and retrograde approach for chronic total occlusion recanalization: Facilitated antegrade fenestration and re-entry.

While antegrade techniques remain the cornerstone of chronic total occlusion (CTO) percutaneous coronary intervention (PCI), operators have often to resort to the retrograde approach in complex occlusions. In particular, lesions with proximal cap ambiguity, unclear vessel course and/or poor distal landing zone are difficult to tackle with either antegrade wiring or antegrade dissection and re-entry (ADR), and often require the retrograde approach. After collateral channel crossing, the retrograde approach usually culminates with either reverse controlled antegrade and retrograde subintimal tracking (CART) or retrograde true lumen crossing. Both techniques usually involve the use of an externalization wire, which requires keeping a higher activate clotting time to prevent thrombosis of the retrograde channel and is potentially associated with risk for donor vessel injury. In 2018, we described antegrade fenestration and re-entry (AFR), a targeted ADR technique in which fenestrations between the false and true lumen are created by antegrade balloon dilatation in the extraplaque space at the level of the distal cap, which are subsequently engaged by a polymer-jacketed wire to achieve re-entry. We hypothesized that AFR can also expedite antegrade crossing of the CTO after a wire has reached the distal vessel in a retrograde fashion. In this report, we present two cases in which we successfully achieved antegrade CTO crossing with AFR following retrograde advancement of a guidewire to the distal cap, in new variant of the technique, which we called "facilitated AFR".

Clinical outcomes of double stent strategy for unprotected left main distal bifurcation lesions using current generation drug eluting stent comparing to early generation drug eluting stent; The Milan and New Tokyo (MITO) registry.

BACKGROUND: There are only little data available on the comparison of clinical outcomes between a early generation drug eluting stent (eDES) and a current generation drug eluting stent (cDES) for percutaneous coronary intervention (PCI) with double stent strategy (DSS) for unprotected distal left main disease (ULMD). METHODS: Between April 2005 and December 2015, we recruited 452 consecutive ULMD patients treated with DSS (eDES, 236 patients; cDES, 216 patients). In this study, eDES included Cipher, Taxus, and Endeavor and cDES included Ultimaster, Resolute family, Xience family, Promus family, Synergy, and Nobori. The primary endpoint was target lesion failure (TLF) defined as a composite of cardiac death, target lesion revascularization (TLR) and myocardial infarction (MI) during the median follow-up period of 1,809(IQR: 1,190-2,510) days. RESULTS: In entire population, the rate of overall TLR was significantly lower in cDES group than that in eDES group (adjusted HR 0.62, 95% CI 0.40-0.96, p = .032). The rate of TLR for the ostium of LCX was significantly lower in cDES group than that in eDES group (adjusted HR 0.63, 95% CI 0.39-0.99, p = .047). Cardiac mortality, the rate of TLR for LM-LAD, MI and definite/probable ST did not significantly differ between both groups. The results were preserved in the propensity adjusted population. CONCLUSIONS: cDES significantly improved the clinical outcomes in population treated with DSS mainly driven by the reduction of TLR for the ostium of LCX.

Cardiac and sudden death after chronic total occlusion percutaneous coronary intervention: Prognostic role of the target vessel.

BACKGROUND: The role of the target vessel in percutaneous revascularization of chronic total occlusion (CTO) is unclear. OBJECTIVE: We sought to assess the long-term results of percutaneous coronary intervention (PCI) for CTO lesions in each coronary artery and to investigate the impact of successful revascularization and previous myocardial infarction (MI) in the territory of the target vessel. METHODS AND RESULTS: Cohort observational study on 1,124 patients who have undergone CTO PCI attempt: 371 on left anterior descending artery (LAD), 485 right coronary artery, and 268 left circumflex. Patients were further stratified by successfully revascularized and not-revascularized CTO (CTO-NR). Vessels affected by a previous MI were defined as infarct-related artery (IRA). The primary endpoint was cardiac death; the secondary endpoint was the combined rate of sudden cardiac-death and sustained ventricular-arrhythmias (SCD/SVAs). Propensity score-matching was performed to evaluate LAD versus NON-LAD CTO. Up to 12-year follow-up, the clinical benefit associated with successful PCI was consistent across the three groups. CTO-NR had the greatest association with cardiac death and SCD/SVAs in each coronary artery and in IRA-CTO patients. CONCLUSIONS: Unsuccessful percutaneous CTO revascularization was associated with lower cardiac survival and freedom from SCD/SVAs, irrespective of the vessel treated. This result was mainly driven by patients with an IRA CTO.

Multicenter experience with the antegrade fenestration and reentry technique for chronic total occlusion recanalization.

OBJECTIVES: We aimed to evaluate the efficacy and safety of antegrade fenestration and reentry (AFR) for chronic total occlusion (CTO) recanalization in a multicenter registry. BACKGROUND: Adoption of antegrade dissection/reentry (ADR) for CTO recanalization has been limited, and novel ADR techniques are needed. METHODS: AFR involves the balloon-induced creation of multiple fenestrations between the false and true lumen. A targeted true lumen reentry is subsequently achieved with a low tip-load polymer-jacketed guidewire. Following the initial description and dissemination of AFR, patients undergoing AFR-based CTO recanalization at nine centers were included in the present registry. Study endpoints were AFR success, procedural success, and target-lesion failure (TLF) on follow-up. RESULTS: We included 41 patients. Mean J-CTO score was 2.5 ± 1.4. In 80.5% of cases, AFR was performed after failed antegrade wire escalation. Another ADR technique was used before AFR in one-third of cases. AFR achieved distal true lumen reentry in n = 27/41 (65.9%) cases. In n = 14/41 (34.1%) cases with AFR failure, use of alternative techniques led to successful CTO recanalization in eight additional patients. The overall technical and procedural success rates were 85.4% and 82.9%, respectively. No AFR-related complications were observed. One-year TLF rate was 8.3% overall, with no differences between successful and failed AFR. CONCLUSIONS: We report on AFR feasibility in a multicenter registry of patients undergoing CTO recanalization. We observed a moderate success rate, coupled with the absence of complications. Moreover, even a failed AFR attempt did not preclude the use of alternative techniques to achieve recanalization. Further studies should confirm and extend our findings.

Guiding Principles for Chronic Total Occlusion Percutaneous Coronary Intervention.

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

Long-term clinical effects of recanalization of chronic coronary total occlusions in patients with left ventricular systolic dysfunction.

OBJECTIVES: The aim of the present analysis is to evaluate the clinical impact of chronic total occlusions (CTOs) recanalization in patients with left ventricular (LV) systolic dysfunction. BACKGROUND: According to contemporary knowledge, patient selection for percutaneous CTO revascularization is not yet standardized. In particular, data on outcomes in patients with LV systolic dysfunction undergoing percutaneous coronary intervention (PCI) for CTO are scarce. METHODS: From a total of 2,421 consecutive patients with at least one CTO, 436 patients with ejection fraction (EF) ≤45%, who were referred for coronary angiography between January 1998 and September 2014, were selected. Patients with successful recanalization of the target CTO were assigned to CTO-revascularized group and those with failed or not attempted recanalization to the CTO-not revascularized (CTO-NR) group. Study endpoints were all-cause death, cardiac death, and occurrence of myocardial infarction on follow-up. RESULTS: Out of 436 CTO patients with reduced EF, 228 (52.3%) were successfully recanalized and 208 patients (47.7%) were not, either due to CTO-PCI failure (n = 106, 24.3%) or because CTO-PCI was not attempted (n = 102, 23.4%). At long-term follow-up, CTO-NR patients had significantly higher rate of overall (p = .021) and cardiac mortality (p = .035) compared to those successfully revascularized. CONCLUSION: In patients with systolic LV dysfunction (EF ≤ 45%), CTO revascularization was associated with significant lower rate of total and cardiac mortality compared to those with nonrevascularized CTO.

Conventional vascular access site approach versus fully trans-wrist approach for chronic total occlusion percutaneous coronary intervention: a multicenter registry.

OBJECTIVES: To evaluate the incidence of vascular complication and major bleeding in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI) with a fully trans-wrist access (TWA) approach versus a conventional approach based on trans-femoral access (TFA). BACKGROUND: TFA is the preferred vascular access in CTO PCI, but it has been associated with a non-negligible risk of complications. METHODS: This retrospective registry included all patients undergoing CTO PCI at five institutions between July 2011 and October 2018. Patients were divided into two groups: Conventional (patients treated with at least one TFA) and Fully TWA (subjects exclusively treated with one or two TWA). The primary safety endpoint was a composite of vascular complications and major bleeding. The primary efficacy endpoint was procedural success. RESULTS: We included 1,900 patients (Conventional n = 1,496 and Fully TWA n = 404). Conventional patients showed higher occlusion complexity (J-CTO score 2.1 ± 1.2 vs. 1.5 ± 1.1, p < .001). Procedural success showed no significant difference between both groups (85.7 vs. 83.0%, p = .17). The primary safety endpoint occurred more frequently in the Conventional group (10.3 vs. 4.5%, p < .001), driven by vascular complications (9.4 vs. 3.7%, p < .001). On multivariate analysis, not using a Fully TWA approach was an independent predictor of the study endpoint, after adjusting for age, sex, diabetes, body mass index, chronic kidney disease, prior coronary artery bypass graft, and J-CTO score. CONCLUSIONS: Embracing a Fully TWA approach for CTO PCI might be associated with lower incidence of a composite endpoint of vascular complications and major bleeding, compared with a Conventional approach.

Contrast modulation in chronic total occlusion percutaneous coronary intervention.

The intraplaque injection of contrast media in the recanalization of coronary chronic total occlusions (CTO) has witnessed a dynamic journey since its initial formulation. Contrast-guided subintimal tracking and re-entry (STAR) was the first contrast modulation technique for CTO percutaneous coronary intervention (PCI). With this technique, a forceful injection of a large volume of contrast (3-4 mL) was performed in order to achieve hydraulic recanalization of the vessel. This approach was associated with extensive vessel injury and unpredictable true lumen re-entry, which were in turn linked to high rates of restenosis on follow-up. In the subsequent iteration, called the "microchannel technique", a smaller amount of contrast media (1 mL) was gently injected inside the plaque to modify its compliance by softening and recruiting loose tissue, which facilitated subsequent true-to-true lumen crossing with a polymer-jacketed wire along paths of least resistance. The microchannel technique has later evolved into what is currently known as the "Carlino technique", where a minimal volume of contrast media (<0.5 mL) is gently injected inside the occlusion, with the goal of modifying plaque compliance to facilitate guidewire and microcatheter advancement through a fibrocalcific plaque. The Carlino technique is now widely utilized to allow negotiation of difficult-to-cross occlusions, particularly by the "hybrid operators", with high success rates and low incidence of complications. The purpose of this article is to provide a historical perspective on the use of contrast modulation in CTO PCI, its pathophysiological basis, as well as technical recommendations on how and when to perform these maneuvers.

Long-term follow-up of covered stent implantation for various coronary artery diseases.

OBJECTIVES: The aims of this study were to evaluate the long-term clinical outcomes after coronary covered stent (CS) implantation and to compare the results according to the indications. BACKGROUND: To date, data on the long-term follow-up of coronary CS are limited, and no studies have been conducted to compare outcomes on the basis of specific lesions treated. METHODS: A total of 190 consecutive patients (212 lesions) implanted with CS and surviving until discharge between May 1997 and February 2017 were enrolled in this retrospective study. Clinical outcomes were evaluated and compared using the Gehan-Breslow-Wilcoxon test. RESULTS: CS was mainly used for the treatment of a saphenous vein graft (SVG) (51.4%), followed by coronary artery perforation (CAP) (25.0%) and coronary artery aneurysm (CAA) (11.8%). The median follow-up duration was 6.0 (interquartile range: 1.6-13.5) years. Target vessel myocardial infarction (MI), target vessel occlusion, target lesion revascularization, and stent thrombosis, frequently occurred in the early follow-up period (7.3%, 16.6%, 21.5%, and 8.9% at 1 year, respectively) and continued to increase throughout the long-term follow-up (14.8%, 38.6%, 38.7%, and 17.8% at 10 years, respectively). Target vessel occlusion, target vessel MI, and ST were not identified in CAA with superiority to CAP (Gehan-Breslow-Wilcoxon p-value = 0.010, 0.047, and 0.046, respectively). SVG had a higher rate of target vessel occlusion than CAA (p = 0.004). CONCLUSIONS: Clinical events after CS implantation frequently occurred in the early period and steadily increased in the long-term period. CS implantation in CAA was associated with fewer adverse cardiac events and may lead to safe and acceptable outcomes. However, CS implanted in CAP and SVG are associated with a high risk of long-term cardiac events.

Rotational atherectomy in the subadventitial space to allow safe and successful chronic total occlusion recanalization: Pushing the limit further.

Dissection and re-entry (DR) techniques have played a key role in the increase of success rates of chronic total occlusion (CTO) recanalization. DR usually allows wiring complex occlusions, even in case of important calcification. In extreme cases, such as in balloon failure-to-cross, rotational atherectomy (RA) might be decisive. However, according to experts' recommendations, RA should not be performed in dissection planes because of the high risk of perforation and further extending the dissection, so that its use after DR might be limited. Here, we describe a case of successful right coronary artery CTO recanalization in which, after failure of several antegrade and retrograde techniques, RA was safely performed antegradely in the subadventitial space, thus eventually enabling reverse controlled antegrade and retrograde subintimal tracking (CART). Although the feasibility of RA in CTO percutaneous coronary intervention had already been suggested, this case reports on the novel use of RA to allow further manipulation of the subadventitial space (reverse CART) prior to successful recanalization. © 2017 Wiley Periodicals, Inc.

Intracoronary snaring of the retrograde guidewire: How to overcome extreme takeoff angles in chronic total occlusion percutaneous coronary intervention.

Extreme angulation of coronary artery takeoff represents a challenge for wiring and device advancement in percutaneous coronary intervention (PCI). This anatomic feature is particularly adverse in cases of chronic total occlusion (CTO) of the ostial-proximal segment of the target vessel. In this setting, the retrograde approach can help getting access to the occlusion. However, difficulties might arise at the critical step of wire externalization, due to the need to overcome the extreme ostial angle. Here, we describe a case of successful CTO PCI of the proximal circumflex artery, which presented an extreme angle at its takeoff. Due to inability to perform antegrade wiring of the occlusion, the retrograde approach was undertaken via epicardial collaterals from the right coronary artery. Since conventional attempts at re-entering the antegrade guiding catheter failed due to the aforementioned extreme angle, the retrograde wire was snared in the mid left anterior descending artery, and externalization was performed. This case demonstrates the usefulness of coronary snares in the CTO operator's toolkit and shows how such devices can be used to safely and successfully complete challenging retrograde procedures.

Antegrade fenestration and re-entry: A new controlled subintimal technique for chronic total occlusion recanalization.

OBJECTIVES: To describe and evaluate the efficacy of a novel antegrade dissection/re-entry (ADR) technique, called antegrade fenestration and re-entry (AFR), for chronic total occlusions (CTO) percutaneous coronary intervention (PCI). BACKGROUND: The widespread adoption of ADR is limited by several technical, logistic, and financial factors. Therefore, novel ADR techniques are needed. METHODS: AFR consists in creating multiple fenestrations of the dissection flap separating the false and true lumen. This is achieved by advancing a balloon (sized 1:1 with the artery diameter) onto the antegrade wire into the subintimal space, and inflating it at the level of the distal cap. A soft polymer-jacketed guidewire is then advanced across the fenestrations created by balloon inflation from the subintimal space into the true lumen. Following its theoretical formulation, patients undergoing ADR-based CTO recanalization at our institution were considered for AFR treatment. RESULTS: Between November 2015 and October 2017, 279 CTO PCIs were performed. Of those, ADR was utilized in 33 (12%) cases, of whom AFR was used in 6 (18%). In all but one cases, AFR was performed after failed true-to-true lumen crossing, while in the remainder it was utilized after extensive subintimal space disruption following alternative ADR techniques. AFR was successful in all six cases and no complications were observed. CONCLUSIONS: We have developed a novel ADR technique which aims at complementing the CTO operator's armamentarium. AFR does not preclude alternative bailout techniques, and is inexpensive and easy to perform. A dedicated study should confirm our findings in a large cohort.

Microcatheter knuckle technique: A novel technique for negotiating the subintimal space during chronic total occlusion recanalization.

OBJECTIVES: To establish if novel microcatheter knuckle technique (MKT) is feasible and efficacious in negotiating the subintimal space in difficult lesions during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). BACKGROUND: CTOs remain one of the most challenging lesion subsets in PCI. Guidewire manipulation and advancement of equipment within the subintimal space is sometimes challenging and aggressive manipulation in the subintimal space is feared, because of concern of vessel disruption and perforation. Here we introduce the MKT, for negotiating the subintimal space during challenging CTO PCI. METHODS: MKT is performed by creating a wire knuckle with polymer-jacketed guidewire and positioned in the subintimal space. Subsequently, a tapered-tip, kink-resistant microcatheter is advanced towards the knuckled tip of guidewire and the guidewire is simultaneously withdrawn; creating a knuckle-shaped microcatheter tip. The MKT was considered in CTO PCIs that involved subintimal techniques where resistance to guidewire knuckle advancement was encountered. Procedures were performed between March 2013 and June 2017 at our institution. RESULTS: During the study period, a total of 440 CTO PCIs were performed, from which seven were treated with MKT. MKT was successful in six patients and technical success was achieved in all seven patients. The MKT was successfully performed with both the antegrade and retrograde approach. CONCLUSION: We present a novel technique for negotiating the subintimal space in CTO PCI for cases where significant resistance is experienced restricting guidewire or material advancement in antegrade or retrograde dissection. The MKT appears to be efficacious complementing the CTO operator's armamentarium.