Bifurcation CAD: Current Techniques and Future Directions
Bifurcation CAD: Current Techniques and Future Directions
The treatment of bifurcation coronary artery disease is a common challenge facing the interventional cardiologist. There have been major advances in techniques as well as more widespread use of drug-eluting stents; both appear to have contributed to the realization of single-digit target lesion revascularization rates as well as improvement in short-term complications such as stent thrombosis. Adequate treatment of the side branch ostium, the site most frequently described as being susceptible to restenosis, has become the focus of newer bifurcation techniques as well as dedicated devices for the treatment of this complex lesion subset. Since main branch reintervention rates are sufficiently low and silent restenosis of the side branch ostium is an all-too-common finding, there is no clear consensus on the optimal treatment strategy for bifurcation coronary disease. The following is a comprehensive review of those commonly used techniques as well as dedicated devices currently under development for the treatment of bifurcation coronary artery disease.
Published randomized trials of drug-eluting stents (DES) have shown reduced rates of restenosis and target lesion revascularization (TLR) in noncomplex lesions compared to bare-metal stents (BMS).Given this documented success of the antiproliferative therapies in relatively simple lesions, interventional cardiologists have developed techniques and devices hoping to demonstrate similarly durable results in more complex lesion subsets. Bifurcation coronary artery disease (CAD) comprises an important subset of lesions inadequately studied and thus far unapproved for DES use. The optimal management strategy for this complex set of lesions continues to be the focus of intense interventional research and debate.
(Enlarge Image)
High-intensity Faxitron radiographic imaging showing the results of provisional side branch stenting performed in beating heart swine models. Standard bifurcation stent techniques often result in "gaps" in stent coverage at the side branch ostium.
(Enlarge Image)
Following main branch and side branch stenting of a bifurcation lesion, intravascular ultrasound demonstrates the limited ability to achieve complete stent coverage at the carina of the bifurcated vessel.
The results of recent bifurcation trials have been disappointing, irrespective of the stent platform or dedicated device used. Relative to percutaneous revascularization of non-bifurcated lesions, higher restenosis rates and unacceptable procedural complications have characterized the bifurcation studies. One of the most frequently cited procedural shortcomings has been the inability to adequately cover the side branch ostium. Depicted angiographically (Figure 1) and also with intravascular ultrasound (IVUS) (Figure 2), this problem has led to an increased incidence of ostial side branch restenosis and subsequent TLR. In addition to gaps in stent coverage at the side branch ostium, the success of current techniques has been limited by such angiographic predictors of failure as stent distortion and redundancy of metal at the carina of the lesion (Figure 3). Both of these have been implicated in the need for TLR, and in the increased incidence of stent thrombosis.
(Enlarge Image)
(A and B) High-intensity Faxitron radiographic imaging from beating heart swine models demonstrates the effect of crush and other standard bifurcation techniques leading to stent disruption and distortion. The effect of this, seen in panel A, is easily appreciated at both the acute and obtuse angles of the side branch origin. Though there may be adequate side branch ostial coverage, a redundant layer of metal at the vessel carina is shown. In panel B, stent disruption can lead to large gaps in stent coverage of the main branch, seen just proximal to the carina. The effect of "stent lift" can be seen on the main branch vessel, contralateral to the side branch origin. This can be seen, as in this swine model, when there is failure to perform final kissing balloon dilatation after bifurcation stent implantation.
The following is a review of those strategies currently being employed in the management of bifurcation CAD. In addition, we will review those dedicated bifurcation devices currently in developmental and testing stages. Bifurcation disease remains a tremendous challenge. As this review will show, success in this arena remains elusive, but the potential for success appears great.
The treatment of bifurcation coronary artery disease is a common challenge facing the interventional cardiologist. There have been major advances in techniques as well as more widespread use of drug-eluting stents; both appear to have contributed to the realization of single-digit target lesion revascularization rates as well as improvement in short-term complications such as stent thrombosis. Adequate treatment of the side branch ostium, the site most frequently described as being susceptible to restenosis, has become the focus of newer bifurcation techniques as well as dedicated devices for the treatment of this complex lesion subset. Since main branch reintervention rates are sufficiently low and silent restenosis of the side branch ostium is an all-too-common finding, there is no clear consensus on the optimal treatment strategy for bifurcation coronary disease. The following is a comprehensive review of those commonly used techniques as well as dedicated devices currently under development for the treatment of bifurcation coronary artery disease.
Published randomized trials of drug-eluting stents (DES) have shown reduced rates of restenosis and target lesion revascularization (TLR) in noncomplex lesions compared to bare-metal stents (BMS).Given this documented success of the antiproliferative therapies in relatively simple lesions, interventional cardiologists have developed techniques and devices hoping to demonstrate similarly durable results in more complex lesion subsets. Bifurcation coronary artery disease (CAD) comprises an important subset of lesions inadequately studied and thus far unapproved for DES use. The optimal management strategy for this complex set of lesions continues to be the focus of intense interventional research and debate.
(Enlarge Image)
High-intensity Faxitron radiographic imaging showing the results of provisional side branch stenting performed in beating heart swine models. Standard bifurcation stent techniques often result in "gaps" in stent coverage at the side branch ostium.
(Enlarge Image)
Following main branch and side branch stenting of a bifurcation lesion, intravascular ultrasound demonstrates the limited ability to achieve complete stent coverage at the carina of the bifurcated vessel.
The results of recent bifurcation trials have been disappointing, irrespective of the stent platform or dedicated device used. Relative to percutaneous revascularization of non-bifurcated lesions, higher restenosis rates and unacceptable procedural complications have characterized the bifurcation studies. One of the most frequently cited procedural shortcomings has been the inability to adequately cover the side branch ostium. Depicted angiographically (Figure 1) and also with intravascular ultrasound (IVUS) (Figure 2), this problem has led to an increased incidence of ostial side branch restenosis and subsequent TLR. In addition to gaps in stent coverage at the side branch ostium, the success of current techniques has been limited by such angiographic predictors of failure as stent distortion and redundancy of metal at the carina of the lesion (Figure 3). Both of these have been implicated in the need for TLR, and in the increased incidence of stent thrombosis.
(Enlarge Image)
(A and B) High-intensity Faxitron radiographic imaging from beating heart swine models demonstrates the effect of crush and other standard bifurcation techniques leading to stent disruption and distortion. The effect of this, seen in panel A, is easily appreciated at both the acute and obtuse angles of the side branch origin. Though there may be adequate side branch ostial coverage, a redundant layer of metal at the vessel carina is shown. In panel B, stent disruption can lead to large gaps in stent coverage of the main branch, seen just proximal to the carina. The effect of "stent lift" can be seen on the main branch vessel, contralateral to the side branch origin. This can be seen, as in this swine model, when there is failure to perform final kissing balloon dilatation after bifurcation stent implantation.
The following is a review of those strategies currently being employed in the management of bifurcation CAD. In addition, we will review those dedicated bifurcation devices currently in developmental and testing stages. Bifurcation disease remains a tremendous challenge. As this review will show, success in this arena remains elusive, but the potential for success appears great.
Source...