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Epicardial collaterals: Off-piste CTO'ing
Cardiovascular Revascularization Medicine 18 (2017) 391–392
Contents lists available at ScienceDirect
Cardiovascular Revascularization Medicine
Editorial
Epicardial collaterals: Off-piste CTO'ing Percutaneous coronary interventions (PCI) of chronic total occlusions (CTO) are among the most technically demanding procedures. While CTOs are present in up to 20–30% [1] of patients undergoing coronary angiography, CTO PCI is only attempted in b 10% [2]. The most commonly cited reasons for the low attempt rate are the lower success rates with CTO PCI and higher procedural complication rates. Historical success rates in CTO recanalization ranged between 50 and 60% [3], but with the advent of the retrograde and hybrid approaches, success rates have increased to as high as 80–90% [4]. Studies have also demonstrated acceptably low complication rates of CTO PCI in the hands of experienced operators [4,5]. As a CTO operator progresses, there are advancing drifts in skill sets beginning with basic procedural preparation, including the use of routine dual injections and microcatheters, that translate to higher success rates. Successful recanalization continues to improve with refined antegrade wiring techniques and proper wire choices. These gradual drifts in success rates become shifts as the operator masters utilization of the subintimal space and controlled dissection re-entry with the Stingray system (Boston Scientific). As one continues to become a complete CTO operator, the most powerful addition to one's quest to achieve a 90% procedural success rate is employment of the retrograde strategy. While necessary for a higher success rate, retrograde CTO PCI has been shown to be associated with higher complication rates than antegrade CTO PCI [6]. A potential reason for the difference has been attributed to the manipulation of collaterals needed to accomplish retrograde CTO PCI. The only 3 options for retrograde CTO PCI are the use of the septal collaterals, bypass grafts, or epicardial collaterals (EC). While all retrograde approaches can be fraught with potential dangers and pitfalls, septal collaterals have traditionally been viewed as the safest channels to traverse during these procedures. Like the groomed slopes of a ski resort, the cascades of connections between the left anterior descending (LAD) artery and posterior descending artery (PDA) offer a certain degree of assurance of safe traveling with minimal opportunities for disastrous accidents. These avenues have been traveled so frequently during similar procedures, and the familiarity with the forgivingness of these connections confers a degree of comfort and confidence in their safety. When navigating retrograde, these potential avenues should be exhausted first before venturing off piste into the more unpredictable terrain of EC. The heterogeneity of epicardial connections is riddled with unknown hidden hazards of often extreme tortuosity, friability, and hidden side branches that may lead one to undesired location and consequence. While taking this way down the mountain may be successful and necessary in situations where other options do not exist, eventually, if selected frequently enough, collisions with buried rocks, unavoidable trees, or unstable snow will lead even the most expert professionals into perils that are often only recognized after the voyager's fate has already been determined. Perforation of these vessels is not infrequent, which can result in cardiac tamponade, hemodynamic compromise, and death if not immediately treated. Preparedness to deal
1553-8389/© 2017 Published by Elsevier Inc.
with these catastrophic consequences mandates that the operator be facile with and have a full arsenal of equipment, including 0.14 compatible coils, to actively treat and extinguish perforations. Until recently, the perceived difficulties and dangers in successfully using EC as opposed to the apparent forgivingness of septal collaterals, while accurate, has largely been anecdotal. Previously, there were no studies to objectively perform a head-to-head comparison of retrograde CTO PCI comparing the use of epicardial collaterals (EC) to non-epicardial collaterals (NEC). In the current issue of Cardiovascular Revascularization Medicine, Benincasa et al. compare the procedural and long-term clinical outcomes of retrograde CTO PCI via EC to NEC [7]. This is the first such study to do so. The main findings of the study are as follows: 1) CTO PCI via EC is associated with lower technical and procedural success rates; 2) numerically higher (although not statistically significant) perforations occur with CTO PCI via EC than NEC; and 3) major adverse cardiac events (MACE) at 2 years are numerically higher (but once again, not statistically significant) with CTO PCI via EC as compared to NEC. The major findings of the study confirm the anecdotal experience of most CTO PCI operators; namely, that technical and procedural outcomes are worse when EC are used (technical success: 35% EC vs. 76% NEC; procedural success: 30% vs. 76%, p b 0.001). While the perforation rates (3% EC vs. 0% NEC) and MACE rates (12.9% EC vs. 5.4% NEC) were not statistically significant between the two types, it is likely due to the small size of the study (75 patients). Given the numerically higher rate of perforations and MACE with EC, a larger patient population would have most likely borne a statistically significant difference. The authors should be commended for undertaking this worthwhile study. However, it should be noted that the study is single-center, single-operator with a small sample size. A larger, multi-center study is needed to confirm − as well as add to − the findings of this study. It should also be noted that epicardial collaterals are quite heterogeneous in terms of their anatomy and complexity. EC with significant redundancy and tortuosity are markedly more difficult to navigate, whereas larger, straighter-caliber EC vessels are easier to negotiate. Furthermore, it should be mentioned that AV groove collaterals are EC that have been shown to be more prone to vascular injury than traditional EC [8] and, therefore, felt by many to be associated with worse outcomes. While this study performed a basic angiographic assessment of collateral tortuosity, an objective assessment of epicardial vessel features was not performed. Future efforts need to focus on defining anatomical characteristics of EC that can predict which potential channels can be crossed successfully without consequential perforation with wires and microcatheters. Traditional concerning qualities of these connections, such as the number and frequency of redundant omega turns, vessel size, regions of angiographic invisibility, and particular anatomic connections need to be systematically databased with a standardized core lab. When such a study is completed, we can hope to develop a scoring mechanism to allow an operator to choose appropriately when it may be safe to travel off the traditional slopes of septal
392
Editorial
connections and venture into the out-of-bounds terrain that EC currently are. Without a clearer understanding of which EC are safe to use, offpiste adventures will continue to occasionally result in complications that will challenge even the most expert operators' abilities to maintain equanimity. William Nicholson, MD Department of Cardiology, York Hospital, York, PA, United States Corresponding author at: 1001 South George Street, York, PA 17403, United States. E-mail address: [email protected] Darshan Doshi, MD, MS Division of Cardiology, Columbia University, New York, NY, United States http://dx.doi.org/10.1016/j.carrev.2017.08.003 References [1] Fefer P, Knudtson ML, Cheema AN, Galbraith PD, Osherov AB, Yalonetsky S, et al. Current perspectives on coronary chronic total occlusions: the Canadian multicenter chronic Total occlusions registry. J Am Coll Cardiol 2012;59(11):991–7. [2] Brilakis ES, Banerjee S, Karmpaliotis D, Lombardi WL, Tsai TT, Shunk KA, et al. Procedural outcomes of chronic total occlusion percutaneous coronary intervention: a report from the NCDR (National Cardiovascular Data Registry). JACC Cardiovasc Interv 2015;8(2):245–53.
[3] Puma JA, Sketch MH Jr., Tcheng JE, Harrington RA, Phillips HR, Stack RS, et al. Percutaneous revascularization of chronic coronary occlusions: an overview. J Am Coll Cardiol 1995;26(1):1–11. [4] Karmpaliotis D, Michael TT, Brilakis ES, Papayannis AC, Tran DL, Kirkland BL, et al. Retrograde coronary chronic total occlusion revascularization: procedural and inhospital outcomes from a multicenter registry in the United States. JACC Cardiovasc Interv 2012;5(12):1273–9. [5] Sianos G, Barlis P, Di Mario C, Papafaklis MI, Büttner J, Galassi AR, et al. European experience with the retrograde approach for the recanalisation of coronary artery chronic total occlusions. A report on behalf of the euroCTO club. EuroIntervention 2008;4(1):84–92. [6] Patel VG, Brayton KM, Tamayo A, Mogabgab O, Michael TT, Lo N, et al. Angiographic success and procedural complications in patients undergoing percutaneous coronary chronic total occlusion interventions: a weighted meta-analysis of 18,061 patients from 65 studies. JACC Cardiovasc Interv 2013;6(2):128–36. [7] Benincasa S, Azzalini L, Carlino M, Bellini B, Giannini F, Zhao X, et al. Outcomes of the retrograde approach through epicardial versus non-epicardial collaterals in chronic total occlusion percutaneous coronary intervention. Cardiovasc Revasc Med 2017; 18(6):393–8. [8] Lee CK, Chen YH, Lin MS, Yeh CF, Hung CS, Kao HL, et al. Retrograde approach is as effective and safe as antegrade approach in contemporary percutaneous coronary intervention for chronic total occlusion: a Taiwan single-center registry study. Acta Cardiol Sin 2017;33(1):20–7.
Contents lists available at ScienceDirect
Cardiovascular Revascularization Medicine
Editorial
Epicardial collaterals: Off-piste CTO'ing Percutaneous coronary interventions (PCI) of chronic total occlusions (CTO) are among the most technically demanding procedures. While CTOs are present in up to 20–30% [1] of patients undergoing coronary angiography, CTO PCI is only attempted in b 10% [2]. The most commonly cited reasons for the low attempt rate are the lower success rates with CTO PCI and higher procedural complication rates. Historical success rates in CTO recanalization ranged between 50 and 60% [3], but with the advent of the retrograde and hybrid approaches, success rates have increased to as high as 80–90% [4]. Studies have also demonstrated acceptably low complication rates of CTO PCI in the hands of experienced operators [4,5]. As a CTO operator progresses, there are advancing drifts in skill sets beginning with basic procedural preparation, including the use of routine dual injections and microcatheters, that translate to higher success rates. Successful recanalization continues to improve with refined antegrade wiring techniques and proper wire choices. These gradual drifts in success rates become shifts as the operator masters utilization of the subintimal space and controlled dissection re-entry with the Stingray system (Boston Scientific). As one continues to become a complete CTO operator, the most powerful addition to one's quest to achieve a 90% procedural success rate is employment of the retrograde strategy. While necessary for a higher success rate, retrograde CTO PCI has been shown to be associated with higher complication rates than antegrade CTO PCI [6]. A potential reason for the difference has been attributed to the manipulation of collaterals needed to accomplish retrograde CTO PCI. The only 3 options for retrograde CTO PCI are the use of the septal collaterals, bypass grafts, or epicardial collaterals (EC). While all retrograde approaches can be fraught with potential dangers and pitfalls, septal collaterals have traditionally been viewed as the safest channels to traverse during these procedures. Like the groomed slopes of a ski resort, the cascades of connections between the left anterior descending (LAD) artery and posterior descending artery (PDA) offer a certain degree of assurance of safe traveling with minimal opportunities for disastrous accidents. These avenues have been traveled so frequently during similar procedures, and the familiarity with the forgivingness of these connections confers a degree of comfort and confidence in their safety. When navigating retrograde, these potential avenues should be exhausted first before venturing off piste into the more unpredictable terrain of EC. The heterogeneity of epicardial connections is riddled with unknown hidden hazards of often extreme tortuosity, friability, and hidden side branches that may lead one to undesired location and consequence. While taking this way down the mountain may be successful and necessary in situations where other options do not exist, eventually, if selected frequently enough, collisions with buried rocks, unavoidable trees, or unstable snow will lead even the most expert professionals into perils that are often only recognized after the voyager's fate has already been determined. Perforation of these vessels is not infrequent, which can result in cardiac tamponade, hemodynamic compromise, and death if not immediately treated. Preparedness to deal
1553-8389/© 2017 Published by Elsevier Inc.
with these catastrophic consequences mandates that the operator be facile with and have a full arsenal of equipment, including 0.14 compatible coils, to actively treat and extinguish perforations. Until recently, the perceived difficulties and dangers in successfully using EC as opposed to the apparent forgivingness of septal collaterals, while accurate, has largely been anecdotal. Previously, there were no studies to objectively perform a head-to-head comparison of retrograde CTO PCI comparing the use of epicardial collaterals (EC) to non-epicardial collaterals (NEC). In the current issue of Cardiovascular Revascularization Medicine, Benincasa et al. compare the procedural and long-term clinical outcomes of retrograde CTO PCI via EC to NEC [7]. This is the first such study to do so. The main findings of the study are as follows: 1) CTO PCI via EC is associated with lower technical and procedural success rates; 2) numerically higher (although not statistically significant) perforations occur with CTO PCI via EC than NEC; and 3) major adverse cardiac events (MACE) at 2 years are numerically higher (but once again, not statistically significant) with CTO PCI via EC as compared to NEC. The major findings of the study confirm the anecdotal experience of most CTO PCI operators; namely, that technical and procedural outcomes are worse when EC are used (technical success: 35% EC vs. 76% NEC; procedural success: 30% vs. 76%, p b 0.001). While the perforation rates (3% EC vs. 0% NEC) and MACE rates (12.9% EC vs. 5.4% NEC) were not statistically significant between the two types, it is likely due to the small size of the study (75 patients). Given the numerically higher rate of perforations and MACE with EC, a larger patient population would have most likely borne a statistically significant difference. The authors should be commended for undertaking this worthwhile study. However, it should be noted that the study is single-center, single-operator with a small sample size. A larger, multi-center study is needed to confirm − as well as add to − the findings of this study. It should also be noted that epicardial collaterals are quite heterogeneous in terms of their anatomy and complexity. EC with significant redundancy and tortuosity are markedly more difficult to navigate, whereas larger, straighter-caliber EC vessels are easier to negotiate. Furthermore, it should be mentioned that AV groove collaterals are EC that have been shown to be more prone to vascular injury than traditional EC [8] and, therefore, felt by many to be associated with worse outcomes. While this study performed a basic angiographic assessment of collateral tortuosity, an objective assessment of epicardial vessel features was not performed. Future efforts need to focus on defining anatomical characteristics of EC that can predict which potential channels can be crossed successfully without consequential perforation with wires and microcatheters. Traditional concerning qualities of these connections, such as the number and frequency of redundant omega turns, vessel size, regions of angiographic invisibility, and particular anatomic connections need to be systematically databased with a standardized core lab. When such a study is completed, we can hope to develop a scoring mechanism to allow an operator to choose appropriately when it may be safe to travel off the traditional slopes of septal
392
Editorial
connections and venture into the out-of-bounds terrain that EC currently are. Without a clearer understanding of which EC are safe to use, offpiste adventures will continue to occasionally result in complications that will challenge even the most expert operators' abilities to maintain equanimity. William Nicholson, MD Department of Cardiology, York Hospital, York, PA, United States Corresponding author at: 1001 South George Street, York, PA 17403, United States. E-mail address: [email protected] Darshan Doshi, MD, MS Division of Cardiology, Columbia University, New York, NY, United States http://dx.doi.org/10.1016/j.carrev.2017.08.003 References [1] Fefer P, Knudtson ML, Cheema AN, Galbraith PD, Osherov AB, Yalonetsky S, et al. Current perspectives on coronary chronic total occlusions: the Canadian multicenter chronic Total occlusions registry. J Am Coll Cardiol 2012;59(11):991–7. [2] Brilakis ES, Banerjee S, Karmpaliotis D, Lombardi WL, Tsai TT, Shunk KA, et al. Procedural outcomes of chronic total occlusion percutaneous coronary intervention: a report from the NCDR (National Cardiovascular Data Registry). JACC Cardiovasc Interv 2015;8(2):245–53.
[3] Puma JA, Sketch MH Jr., Tcheng JE, Harrington RA, Phillips HR, Stack RS, et al. Percutaneous revascularization of chronic coronary occlusions: an overview. J Am Coll Cardiol 1995;26(1):1–11. [4] Karmpaliotis D, Michael TT, Brilakis ES, Papayannis AC, Tran DL, Kirkland BL, et al. Retrograde coronary chronic total occlusion revascularization: procedural and inhospital outcomes from a multicenter registry in the United States. JACC Cardiovasc Interv 2012;5(12):1273–9. [5] Sianos G, Barlis P, Di Mario C, Papafaklis MI, Büttner J, Galassi AR, et al. European experience with the retrograde approach for the recanalisation of coronary artery chronic total occlusions. A report on behalf of the euroCTO club. EuroIntervention 2008;4(1):84–92. [6] Patel VG, Brayton KM, Tamayo A, Mogabgab O, Michael TT, Lo N, et al. Angiographic success and procedural complications in patients undergoing percutaneous coronary chronic total occlusion interventions: a weighted meta-analysis of 18,061 patients from 65 studies. JACC Cardiovasc Interv 2013;6(2):128–36. [7] Benincasa S, Azzalini L, Carlino M, Bellini B, Giannini F, Zhao X, et al. Outcomes of the retrograde approach through epicardial versus non-epicardial collaterals in chronic total occlusion percutaneous coronary intervention. Cardiovasc Revasc Med 2017; 18(6):393–8. [8] Lee CK, Chen YH, Lin MS, Yeh CF, Hung CS, Kao HL, et al. Retrograde approach is as effective and safe as antegrade approach in contemporary percutaneous coronary intervention for chronic total occlusion: a Taiwan single-center registry study. Acta Cardiol Sin 2017;33(1):20–7.