Percutaneous recanalization of chronically occluded coronary arteries: Procedural techniques, devices, and results

Percutaneous coronary intervention (PCI) of chronically occluded coronary arteries represents the greatest technical challenge for the interventional cardiologist 1, 2. Compared to intervention of nonoccluded stenoses, recanalization of chronic total occlusions (CTOs) requires more operator skill and procedural time, increases radiation exposure to the patient, physician, and catheterization laboratory staff, and consumes significantly greater resources. In no other lesion subset does the procedural success rate vary as much from physician to physician as with intervention in CTOs, and a definite learning curve exists in which technical success rates for individual operators continue to improve after the performance of hundreds of CTO procedures 3. Moreover, until recently, the clinical benefits of CTO recanalization had not been clearly demonstrated, which, in concert with the technical complexity of the procedure, resulted in many patients with CTOs being either treated medically or referred to bypass graft surgery. There is now an increasing body of published evidence demonstrating that successful percutaneous recanalization of occluded coronary vessels subtending viable myocardium not only reduces angina and improves quality of life, but also improves left ventricular function and is strongly associated with enhanced survival 4-6. Moreover, long-term patency and freedom from restenosis after successful recanalization of CTOs may be greatly enhanced by implantation of drug-eluting stents. As a result, tremendous interest has recently emerged among interventional cardiologists to learn the principles and develop the advanced skills required to maximize procedural outcomes in chronic coronary occlusions. In the first decade after the introduction of balloon angioplasty, technical success rates for PCI in true CTOs were achieved in only 40–57% of cases, reflecting the reliance on suboptimal guidewires, catheters, and dilatation equipment 7-10. In the last 20 years, the procedural outcomes of intervention for CTOs have increased significantly as a function of improved guidewires and devices, as well as operator technique and experience, such that successful recanalization of true CTOs may now be achieved in approximately 80% of lesions 4, 5. In order to achieve consensus on the techniques, methods, and devices required to maximize the likelihood of successful recanalization, an international group of 47 physicians from nine countries was convened in New York City in January 2004, representing many of the world's leading operators and thought leaders in the subspecialty of CTO intervention. Over a 2-day period, collective experiences were evaluated in detail and procedural outcomes were examined though a series of didactic lectures, roundtable discussions, breakout focus groups, and the performance of 14 live case demonstrations of complex angioplasty in occluded coronary arteries. Summarizing the lessons and guidelines generated from this summit, the present article will review the basic principles and advanced techniques required to develop expertise in CTO angioplasty and highlight the major innovations responsible for the current progress being achieved in the percutaneous revascularization of chronic total coronary occlusions. Appropriate patient selection is dependent on the experience of the operator in relation to the clinical and anatomic complexity of the CTO. Traditional predictors of lesion success have included shorter duration of the occlusion (< 3 months), functional total occlusions (those with TIMI 1 flow, which are no longer considered true CTOs), shorter lesion length, presence of a tapered or funneled stump, absence of a side branch at the occlusion site, minimal vessel and lesion tortuosity, absence of calcification, nonostial occlusion location, and a well-formed ipsilateral or contralateral collateral supply clearly delineating the vessel course distal to the occlusion 4, 11-16. Conversely, the presence of bridging collaterals has traditionally been the strongest correlate of procedural failure 3, 4, 11, 12, 16. However, with improvements in guidewire technology and procedural technique and experience, even bridging collaterals no longer represent the harbinger of procedural failure as once believed 2, 4, 10. As a operators with occlusions of tapered and absence of bridging and to more complex as the CTO the only is the absence of a distal is to success rates of CTO operator review of the occluded vessel in by as well as collateral vessels contralateral required to a of the the and the vessel course and side as well as as an of vessel the CTO is and bridging collaterals have is to the true of a functional occlusion which may be and from or of a bridging which be or with patient, the of be to the the of contralateral may be an the to technique the of to 1 patients PCI be treated with at of at to the CTO angioplasty is an procedure, with a of at the in of implantation the is are for PCI of nonoccluded stenoses, that and are of the increased procedural of may be angioplasty once the guidewire has the lesion and to be the may be to achieve an of approximately until the guidewire has the after which be dilatation to achieve an of a is not be angioplasty, and the as as the a is be after successful PCI of a and are the as PCI of a nonoccluded vessel for a of after a 3 after a and after a requires of and the likelihood of devices or or an balloon the lesion is a balloon a CTO be is for CTO angioplasty by with of for though may be considered for occlusions or by operators with catheters, the to more a a that be with PCI of CTOs a is for contralateral a or be the contralateral or either though from the ipsilateral may be an by 1 and to the the may be an for CTO angioplasty by operators in cases, a no is the distal vessel is from ipsilateral collateral flow, the of the occlusion is or and in the presence of the left coronary left are catheters, which are associated with success with occlusions. the coronary left in the are with a or though may be considered for the with or or for have side to of the and of the of the or not with the may the coronary a that be and guidewire of the CTO is the of the and the at which success or failure is There are to a the the body of the CTO to the distal and the distal guidewire selection and technique are procedural success rates are to be of guidewires are which may be for CTO the of which are in for CTOs be or guidewires and may be with and with tapered to has and for CTOs, and has present the consensus is for operators to with but to or at for is true or operators guidewires for CTO intervention. are more to and to to more the but the in of the and the as the tapered with or have even a CTO. greater of is to the distal of a CTO and not a as the but is to the to a are 3 with of more to is and the operators tapered the which to and in greater from to with the to of and the technical success of from to and the occluded In a PCI of CTO revascularization with tapered guidewires, technical success was achieved in of in the presence of a the success rates from to with distal in also and the vessel and be by of and with minimal and even and in vessels to may be more in a true after a Conversely, in a true are more to and not as and not the of once in a a may be for to a greater to that also to and more may be to to also more bridging collaterals and the dilatation of which may in and the operator to that a has a or branch and a and is to the distal course of in at and a balloon the balloon and are in the true a of operators as of for CTOs the to the success or are the the in from the to the with increasing the and and the and and the but also the with the As with are with to guidewires in guidewires to the occlusion is In such cases, the may be to with a which be for a for CTO after an balloon angioplasty to the of the such as the may also be a is with an that may to the distal be in this not to a a case a the is a that to and is at the the as the the vessel and the body of the occlusion at the distal of and tapered this is in and be for CTO a guidewire or has the occlusion and has been the distal vessel and the lesion with an balloon dilatation be and a to the of distal or to CTO intervention is the of a balloon angioplasty balloon or an the or technique improves and or In CTOs be first with the guidewires for PCI in nonoccluded As many as of CTOs that are believed to be or may be with by the by the balloon to the the of the may be the occlusion is the course of the vessel and a curve of the are to the may be in the to the to the of the guidewire increasing the the the may be for a with a greater the is the be the body of the CTO to the distal which requires experience and reliance on of the course of the as well as collateral of the distal or occluded as to the vessel an in the the be the curve to an occlusion on a the coronary the to the of the curve in a be the curve of the vessel occlusions 3 at the to a of the distal for the of distal is the In the to to the distal is on the and the of lesions the technique to occlusions be to a side branch at the of the CTO. that the side branch may the operator the true vessel the guidewire will the side and may be to the As a last dilatation of the with a angioplasty balloon in the side branch may the and to the to be the vessel and the to the true the a to the true will an that of the true and of the Moreover, and the which reduces and may a that the true has been the has a the technique is the to the true the of and In the a is to have a is left in to the and a and with a and by an balloon is the to the first with to the first in also the of in the vessel and a to the the of a or more may be In a the are by angioplasty and are to the occlusion to the true a at the of the distal coronary is left in as a and a in this with a and curve is in and the of an occluded coronary first has a the a by an balloon is to the true In cases, the CTO be from an but the true be from a a collateral vessel a or a bypass graft that with the distal is the distal vessel the occlusion and to the of the distal which is more from either as a or a that be to of a in an the CTO be the collateral or a have that of a guidewire a is a to recanalization of CTOs a true from a by side only from the true and and the true but not the the guidewire has the true from a case with a by is in have also that the major that is to the distal the true is that the guidewire to a not of or in to the that is in a chronic total occlusion of the left coronary guidewire was first and was a to the is in the true was this and of the and of demonstrating that the is in the true and by first is the of is to be in the true as by a side branch the and distal of a chronic total and at of a chronic total occlusion of at the of the left after with a is at the of the and a were at the distal was to the true at the distal of occlusion as the guidewire the distal a also be in the of a CTO the is occluded or the is In such cases, the be a side branch to the of the occlusion and of the of this of to a CTO is in of the of in the of an occlusion of the of an branch of the is with at a demonstrating the absence of a side demonstrating the occluded branch by an the the in the branch in the left a is to the is to the of the to the of the the is the body of the first to a CTO be with an balloon dilatation with a tapered and a to even occlusions. and have an from balloon to operators an which but may not as and of course the dilatation function of a balloon angioplasty and contralateral is the distal is in the true the balloon may be the occlusion to the and the distal vessel is not the balloon may be the the guidewire and a of the guidewire distal be as a of last as will either of the or a the the occlusion is and with the the true of the CTO may be and balloon angioplasty and implantation with be that in the distal vessel is after CTO recanalization, and of or other the true vessel is not the CTO with a balloon angioplasty may be in to of cases, to the presence of is that may be considered for such of and more introduction of a a branch to the occlusion to the of the or in the true to the first to the of the which is of an angioplasty balloon either in the vessel or in a side branch to the and of have not a for of CTOs to restenosis or may balloon or of CTOs is the guidewire with the and an is not required as a is in this is an a is not of this requires the occlusion with a such a will be to the guidewire by the an was to the is with an the lesion be with a balloon angioplasty with and stents. angioplasty or be is that the is in the true with is to to occlusions is the of the in which of an with on the distal of the which may be the CTO. Compared to nonoccluded stenoses, CTOs are by greater length, calcification, and that restenosis rates after have the chronic of balloon angioplasty and implantation after successful recanalization of CTOs in a total of patients In the rates of restenosis were from after balloon angioplasty to after the rates of were from to and the to vessel revascularization rates were from to of in patency of the vessel to balloon angioplasty has been to for or more restenosis and rates after implantation in CTOs have been to in as many as and of In this experience with and in CTOs that long-term clinical and outcomes may be improved to In a experience at the in the revascularization was required in only of patients with CTOs in were 1 case of from major at 1 was significantly improved to the from a group of patients treated in the with In a in which were in CTOs, the rates of restenosis and major were only and in clinical and restenosis rates in CTOs after with to with have also been intervention at 1 was required in only of patients with CTOs in the international in were at a has not been to the and of drug-eluting in CTOs, that devices are to patency rates and freedom from angina and the for vessel revascularization after PCI in occluded coronary arteries to with or greater benefits in nonoccluded of the of the occlusion and distal is after PCI of chronically occluded As a result, after intervention in occluded which the of in in approximately of with in balloon be strongly considered to PCI of occluded the is left ventricular is is in not by the a occlusion is with successful guidewire the challenge is to and the at of had success rates of but were associated with a rate of and and the technique is to a distal with of the to and the has been a balloon is first the of the graft and the the this will a of treated with a are with a balloon is to a that of a distal to implantation of the or as either a or in with distal PCI of occluded is There is no evidence that are in intervention and are not though have not been PCI of occluded the technical and associated with PCI of chronically occluded be to the coronary vessel in of the occluded However, of bypass the coronary in lesions in the that are the vessel of the occluded is associated with success and As was more a decade angioplasty of occluded in a challenge CTO angioplasty is considered to be a procedure, an by the that the presence of an occluded and vessel is a that the be that increasing procedural success rates with CTO angioplasty in patients a at the the major rates time, which at was to the rate in a of patients PCI of nonoccluded after PCI intervention in this series included in of in in bypass in and angioplasty in that may with greater after PCI of occluded to nonoccluded the collateral occlusion of side at the of the left or coronary or guidewire and vessel with [1, a CTO is to the operator the likelihood of success with the of that an but as the of radiation exposure of or in a patient with much in patients to the of a is of collaterals in of of the distal and patient or operator after a CTO to vessel may be successful in of the of failure is and a has been As is from this the skill required to in CTO angioplasty is significantly from that for PCI of in CTO recanalization Conversely, complex CTOs not be until the learning curve has been As a a for CTOs may be to patient selection and for of experience PCI of a CTO is at a more operator a in to vessel and of to of a CTO have the to major a to and and the to even and either or an devices have been to many of which have of which are in current and of which are lessons may be by the failure of to was to CTOs with the of such as that were associated with in the of a of or in with a distal of or was for to of the the leading to or this in CTOs success in of with the in to a success rate of in CTO lesions treated at the with with the was to to the occlusion in of and to with a balloon or the lesion in a of procedures included in bypass in and in rate of with the was the occlusions that not be with the were successful with the occlusions with a the was successful in In a patient of the techniques which was the success rate was in the group In the success rate after was also this was or and the to of a with a at the distal which was by an at a of to a in the the and was in patients with the in in the of the as well as to and distal of this was of to a distal of at to In a series of occlusions that not be the success rate with the was in of cases, which was with patients bypass surgery. of this was not of a of in with improved with a distal was the with of and a rate of In the patients with CTOs were to either the or lesion was achieved in of the in the of the was to be to in in the and to of a in a in the rate of was not significantly the and were no of was not to the of this and the of to devices were to for the recanalization of CTOs to the guidewires of the the and had the to major was the of a to the to that the devices are in in the for CTOs, the guidewire and the guidewire the of a guidewire with that the operator the 1 of the vessel In is to the of from of the from and vessel to the a in from the in the and In this the operator to of the vessel and the to the vessel is not the also be to a of to the to the occluded with and the is in with the only the curve and the is the 1 of the vessel the curve a at the vessel and the in to the operator not to the the has been to at the vessel such that the to and is in for be and the advanced experiences the of this was in the of a in patients with CTOs to a with guidewires occlusion duration was of CTOs were more 1 with lesion of in of of success with guidewires were a to the occluded in and bridging collaterals in success of guidewire in the distal was achieved in of and was of vessel location, occlusion lesion and collateral in of of There were no or bypass in patients of which was to be to the with to the of after the had to is to and an a CTO distal is and as the is the and recanalization for the as has to and with patient outcomes from at the of this patients in the the with an of patients in a a more with an of and patients the current with a distal a with a that was from of the and of the technique is to the occlusion a by the are advanced the lesion and and the of the occlusion is until the either to the distal true or that may be for a guidewire to the recanalization balloon angioplasty by implantation is CTO was coronary left and the in the was in of success of a was achieved in of in the in the and with the current duration of was rates were in the left and with the but were in the coronary a in to the lesion in coronary rates were of lesion length, have been in of has also been to be in patients with CTOs, the to and the the occlusion may be successful in in which guidewires have with an However, the not with and were to the introduction of the current of guidewires, which have clearly enhanced success has achieved at the of and but improvements have enhanced procedural success rates for for the of devices after a minimal with guidewires major vessel and after or more with no consensus be the for devices, though after failure to the CTO with with devices is with to and are being for has been for more a decade as a to occlusions a of and to the of the as a to the occlusion the at or the CTO are to in of to as the and to a by of in concert with of of from the though the in the of or is not and may be by In and in have that is not to and In is does not in or and of are in to CTOs was first in in 14 patients at clinical with the 20 success was in included and and procedural complexity of this recently, a 20 is is and has a this has been in patients with CTOs to a with a success rate of with an major with in the is is a technique to guidewire which has been coronary guidewire is an that of the from the distal the of the is to the angioplasty a that a of and in the with of of the the balloon is advanced to the of the the for the of of increasing may be of is and guidewire techniques and vessel is guidewire and has been in coronary CTOs at either as or after techniques had with angioplasty have been from the cases, in which technical and success rates of and were achieved of failure included duration of the occlusion lesion and the of and were in and of cases, but no In a angioplasty was to be to guidewires success rates is the of angioplasty and techniques in with guidewires is also of and a is the failure for CTO intervention. a is may be to the true even for the the represents a to the true from a has a tapered that a with a which for as well as of the is the a and and the true is and the the has the true a is the is and angioplasty is to the the with the true is to the was in a but to the current has been only in total with a technical success rate from to with an the a that is the true However, chronic patency rates with angioplasty and have been long-term also be and and improved devices are to be for coronary occlusions. and of in patients with an are also the has also been to an and a in coronary or an to revascularization of patients with which is of this is true percutaneous in coronary bypass which, though has been in patients that many CTOs represent of has to of to the that of patients with CTOs to with be after an of of that after an to increased by 1 TIMI in of CTOs to techniques, and that PCI was successful in have been achieved with from have been required in of patients with this are at with success rates and the for a successful to techniques will be required to of this of is the to successful guidewire In this is that the success of in CTOs may be to of such as this examined the of to the of chronically occluded arteries to recanalization a occlusions were in New and to for coronary CTOs, as a chronic occlusion with no with and that to with guidewires were for to an balloon with either a or of of In a in occluded was a in guidewire at in to arteries and evidence of of the in the vessels There were no in or of the and was present in the with this technique is with the of that a of approximately in the of the be in the of guidewires or to with greater and with the distal guidewire to or of occlusions and to after the distal the the to the physician to the and in the were or to a have been with this in CTOs has not been and in this may on other guidewire required for CTO recanalization the introduction of such as the and CTO be major challenge the guidewire the true an by the of a to the true of the have been considered the to the success rates of CTO guidewire recanalization In this of was more a decade with a which a of the In the last years, interest has to and progress has been with a 20 technology that may have of and on the of a to be presence of or more CTOs that are to be is the that patients are referred to bypass PCI the last of guidewires that with increasing operator experience and procedural techniques, has significantly the of CTOs that now be considered success rates for CTOs will continue to improve with the and of and As in this a of skills and are required to develop expertise in the subspecialty of CTO of in CTO intervention requires exposure to complex cases, which be a of at live case CTOs and performance of complex CTO with operators have the learning operators learn individual experience in complex with an on patient is that a of the principles will as a for and a to the interventional experience required in occluded coronary arteries to the challenge of the last of percutaneous coronary intervention.