Saphenous vein graft disease treatment: Difference between revisions
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==Treatment Options== | ==Treatment Options== | ||
There are many different choices to consider when deciding the most appropriate treatment for [[SVG]] [[stenosis]], including conventional balloon angioplasty ([[PTCA]]), [[PCI]] with [[bare metal stent|bare metal]] or [[drug-eluting stents]], [[PCI]] with covered [[stents]], embolic protection devices, [[debulking]]/[[thrombus]] removal, and surgical [[revascularization]]. | There are many different choices to consider when deciding the most appropriate treatment for [[SVG]] [[stenosis]], including conventional balloon angioplasty ([[PTCA]]), [[PCI]] with [[bare metal stent|bare metal]] or [[drug-eluting stents]], [[PCI]] with covered [[stents]], embolic protection devices, [[debulking]]/[[thrombus]] removal, and surgical [[revascularization]]. | ||
===Conventional Percutaneous Transluminal Coronary Angioplasty (PTCA) or (POBA)=== | ===Conventional Percutaneous Transluminal Coronary Angioplasty (PTCA) or (POBA)=== | ||
[[PTCA]] has high initial [[revascularization]] success rates in the treatment of SVG [[stenosis]]. However, it is also associated with high rates of periprocedural complications, including acute vessel closure secondary to [[dissection]] and in-situ [[thrombosis]]. Additional complications include [[embolism|distal embolization]] and [[no reflow]], which can lead to periprocedural [[infarction]]. | [[PTCA]] has high initial [[revascularization]] success rates in the treatment of SVG [[stenosis]]. However, it is also associated with high rates of periprocedural complications, including acute vessel closure secondary to [[dissection]] and in-situ [[thrombosis]]. Additional complications include [[embolism|distal embolization]] and [[no reflow]], which can lead to periprocedural [[infarction]]. | ||
In modern [[interventional cardiology]], [[PTCA]] is not often used as the sole means of treatment for SVG [[stenosis]]. Instead, [[stenting]] has become the cornerstone of treatment, while the use of [[PTCA]] has been limited to pre-dilation and post-dilation. An exception would be a scenario in which a stent cannot be advanced through the saphenous vein graft to the lesion. | In modern [[interventional cardiology]], [[PTCA]] is not often used as the sole means of treatment for SVG [[stenosis]]. Instead, [[stenting]] has become the cornerstone of treatment, while the use of [[PTCA]] has been limited to pre-dilation and post-dilation. An exception would be a scenario in which a stent cannot be advanced through the saphenous vein graft to the lesion. | ||
===PCI with Bare Metal Stents (BMS) or Drug-eluting Stents (DES)=== | ===PCI with Bare Metal Stents (BMS) or Drug-eluting Stents (DES)=== | ||
Most current vein graft treatment strategies utilize PCI with stents ([[BMS]] or [[DES]]), since stenting is a superior treatment when compared to [[PTCA]] alone. As demonstrated in the SAVED (Saphenous Vein De Novo) Trial<ref name="pmid9287229">{{cite journal |author=Savage MP, Douglas JS, Fischman DL, ''et al.'' |title=Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators |journal=N. Engl. J. Med. |volume=337 |issue=11 |pages=740–7 |year=1997 |month=September |pmid=9287229 |doi= |url=}}</ref>, the use of [[stents]] is associated with higher [[revascularization]] success rates, decreased [[restenosis]] rates, and improved clinical outcomes when compared to [[PTCA]]. Generally, [[DES]] are preferred over [[BMS]], since [[DES]] are associated with reduced rates of [[restenosis]] and target vessel [[revascularization]]. | Most current vein graft treatment strategies utilize PCI with stents ([[BMS]] or [[DES]]), since stenting is a superior treatment when compared to [[PTCA]] alone. As demonstrated in the SAVED (Saphenous Vein De Novo) Trial<ref name="pmid9287229">{{cite journal |author=Savage MP, Douglas JS, Fischman DL, ''et al.'' |title=Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators |journal=N. Engl. J. Med. |volume=337 |issue=11 |pages=740–7 |year=1997 |month=September |pmid=9287229 |doi= |url=}}</ref>, the use of [[stents]] is associated with higher [[revascularization]] success rates, decreased [[restenosis]] rates, and improved clinical outcomes when compared to [[PTCA]]. Generally, [[DES]] are preferred over [[BMS]], since [[DES]] are associated with reduced rates of [[restenosis]] and target vessel [[revascularization]]. | ||
Despite their higher success rates, stents are not immune to [[restenosis]]. Predictors for [[restenosis]] include long [[stent]] length, multiple [[stents]], overlapping [[stents]], smaller vessel size, [[diabetes mellitus]], and [[stenosis]] at the coronary or aortic [[anastomosis]]. | Despite their higher success rates, stents are not immune to [[restenosis]]. Predictors for [[restenosis]] include long [[stent]] length, multiple [[stents]], overlapping [[stents]], smaller vessel size, [[diabetes mellitus]], and [[stenosis]] at the coronary or aortic [[anastomosis]]. | ||
===PCI with Covered Stents=== | ===PCI with Covered Stents=== | ||
Theoretically, [[stents]] covered with a polymer membrane would have higher success rates than standard [[BMS]] and [[DES]]. One would expect covered stents to effectively trap friable [[atheroma]] and isolate the graft [[Lumen (anatomy)|lumen]] from the diseased wall, thereby reducing incidence of [[restenosis]], distal [[embolization]], and [[no reflow]] in comparison to traditional [[stents]]. However, the RECOVERS (The Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts)<ref name="pmid12821546">{{cite journal |author=Stankovic G, Colombo A, Presbitero P, ''et al.'' |title=Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial |journal=Circulation |volume=108 |issue=1 |pages=37–42 |year=2003 |month=July |pmid=12821546 |doi=10.1161/01.CIR.0000079106.71097.1C |url=}}</ref> and STING (STents IN Grafts)<ref name="pmid14563575">{{cite journal |author=Schächinger V, Hamm CW, Münzel T, ''et al.'' |title=A randomized trial of polytetrafluoroethylene-membrane-covered stents compared with conventional stents in aortocoronary saphenous vein grafts |journal=J. Am. Coll. Cardiol. |volume=42 |issue=8 |pages=1360–9 |year=2003 |month=October |pmid=14563575 |doi= |url=}}</ref> trials did not show any advantage in using covered [[stents]] when compared to [[bare metal stents]] for [[SVG lesions]]. | Theoretically, [[stents]] covered with a polymer membrane would have higher success rates than standard [[BMS]] and [[DES]]. One would expect covered stents to effectively trap friable [[atheroma]] and isolate the graft [[Lumen (anatomy)|lumen]] from the diseased wall, thereby reducing incidence of [[restenosis]], distal [[embolization]], and [[no reflow]] in comparison to traditional [[stents]]. However, the RECOVERS (The Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts)<ref name="pmid12821546">{{cite journal |author=Stankovic G, Colombo A, Presbitero P, ''et al.'' |title=Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial |journal=Circulation |volume=108 |issue=1 |pages=37–42 |year=2003 |month=July |pmid=12821546 |doi=10.1161/01.CIR.0000079106.71097.1C |url=}}</ref> and STING (STents IN Grafts)<ref name="pmid14563575">{{cite journal |author=Schächinger V, Hamm CW, Münzel T, ''et al.'' |title=A randomized trial of polytetrafluoroethylene-membrane-covered stents compared with conventional stents in aortocoronary saphenous vein grafts |journal=J. Am. Coll. Cardiol. |volume=42 |issue=8 |pages=1360–9 |year=2003 |month=October |pmid=14563575 |doi= |url=}}</ref> trials did not show any advantage in using covered [[stents]] when compared to [[bare metal stents]] for [[SVG lesions]]. | ||
===Embolic Protection Devices=== | ===Embolic Protection Devices=== | ||
During [[PCI]] of [[SVGs]], [[Atheroembolism|atheroembolic]] debris can be liberated. This debris contains [[vasoactive]] substances that can contribute to [[no reflow]], which can in turn considerably increase the risk of major adverse clinical events (MACE)<ref name="pmid16264199">{{cite journal |author=Salloum J, Tharpe C, Vaughan D, Zhao DX |title=Release and elimination of soluble vasoactive factors during percutaneous coronary intervention of saphenous vein grafts: analysis using the PercuSurge GuardWire distal protection device |journal=J Invasive Cardiol |volume=17 |issue=11 |pages=575–9 |year=2005 |month=November |pmid=16264199 |doi= |url=}}</ref>. Fortunately, embolic protection devices help capture this debris and improve outcomes in [[PCI]] for [[SVG]] [[stenosis]]. Therefore, it is recommended that these devices should be utilized in the intervention of most [[SVG]] lesions. | During [[PCI]] of [[SVGs]], [[Atheroembolism|atheroembolic]] debris can be liberated. This debris contains [[vasoactive]] substances that can contribute to [[no reflow]], which can in turn considerably increase the risk of major adverse clinical events (MACE)<ref name="pmid16264199">{{cite journal |author=Salloum J, Tharpe C, Vaughan D, Zhao DX |title=Release and elimination of soluble vasoactive factors during percutaneous coronary intervention of saphenous vein grafts: analysis using the PercuSurge GuardWire distal protection device |journal=J Invasive Cardiol |volume=17 |issue=11 |pages=575–9 |year=2005 |month=November |pmid=16264199 |doi= |url=}}</ref>. Fortunately, embolic protection devices help capture this debris and improve outcomes in [[PCI]] for [[SVG]] [[stenosis]]. Therefore, it is recommended that these devices should be utilized in the intervention of most [[SVG]] lesions. | ||
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The FDA-approved proximal occlusion device is called the Proxis® device. Some advantages of this decide are that its deployment does not require crossing the [[stenosis]], it provides superior support that is helpful where balloon or [[stent]] delivery is difficult, and it provides protected crossing of the [[lesion]], if required. However, as shown by the PROXIMAL (Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System) trial<ref name="pmid17919563">{{cite journal |author=Mauri L, Cox D, Hermiller J, ''et al.'' |title=The PROXIMAL trial: proximal protection during saphenous vein graft intervention using the Proxis Embolic Protection System: a randomized, prospective, multicenter clinical trial |journal=J. Am. Coll. Cardiol. |volume=50 |issue=15 |pages=1442–9 |year=2007 |month=October |pmid=17919563 |doi=10.1016/j.jacc.2007.06.039 |url=}}</ref>, in terms of overall outcomes, there is no significant difference in death, [[MI]], or target vessel [[revascularization]] (TVR) between distal and proximal [[embolic]] protection devices. | The FDA-approved proximal occlusion device is called the Proxis® device. Some advantages of this decide are that its deployment does not require crossing the [[stenosis]], it provides superior support that is helpful where balloon or [[stent]] delivery is difficult, and it provides protected crossing of the [[lesion]], if required. However, as shown by the PROXIMAL (Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System) trial<ref name="pmid17919563">{{cite journal |author=Mauri L, Cox D, Hermiller J, ''et al.'' |title=The PROXIMAL trial: proximal protection during saphenous vein graft intervention using the Proxis Embolic Protection System: a randomized, prospective, multicenter clinical trial |journal=J. Am. Coll. Cardiol. |volume=50 |issue=15 |pages=1442–9 |year=2007 |month=October |pmid=17919563 |doi=10.1016/j.jacc.2007.06.039 |url=}}</ref>, in terms of overall outcomes, there is no significant difference in death, [[MI]], or target vessel [[revascularization]] (TVR) between distal and proximal [[embolic]] protection devices. | ||
===Debulking/Thrombus Removal=== | ===Debulking/Thrombus Removal=== | ||
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* Laser atherectomy uses [[monochromatic]] light energy to disrupt [[plaques]]. Despite this approach's innovation, there is no evidence that this strategy improves outcomes in lesions, and it has been complicated by high rates of [[dissection]] and [[perforation]]. | * Laser atherectomy uses [[monochromatic]] light energy to disrupt [[plaques]]. Despite this approach's innovation, there is no evidence that this strategy improves outcomes in lesions, and it has been complicated by high rates of [[dissection]] and [[perforation]]. | ||
===Surgical Revascularization=== | ===Surgical Revascularization=== | ||
Given increased perioperative [[mortality]] in a "re-do" case, surgical revascularization is not an optimal treatment strategy, as many patients with [[graft disease]] are poor surgical candidates. However, surgery may be required in patients with multi-vessel disease and when [[PCI]] fails. | Given increased perioperative [[mortality]] in a "re-do" case, surgical revascularization is not an optimal treatment strategy, as many patients with [[graft disease]] are poor surgical candidates. However, surgery may be required in patients with multi-vessel disease and when [[PCI]] fails. | ||
It should also be noted that reoperation often does not provide the same level of [[revascularization]] and resolution of [[angina]] as the initial procedure. Furthermore, a [[LIMA]] may be jeopardized in a reoperation. | It should also be noted that reoperation often does not provide the same level of [[revascularization]] and resolution of [[angina]] as the initial procedure. Furthermore, a [[LIMA]] may be jeopardized in a reoperation. | ||
==Adjunctive Pharmacotherapy== | ==Adjunctive Pharmacotherapy== | ||
Zoghbi et al. conducted a study to investigate the role of pretreatment with [[nitroprusside]] before [[SVG]] intervention<ref name="pmid19182287">{{cite journal |author=Zoghbi GJ, Goyal M, Hage F, ''et al.'' |title=Pretreatment with nitroprusside for microcirculatory protection in saphenous vein graft interventions |journal=J Invasive Cardiol |volume=21 |issue=2 |pages=34–9 |year=2009 |month=February |pmid=19182287 |doi= |url=}}</ref>. They studied sixty-four consecutive patients with normal preprocedural cardiac [[enzymes]] that underwent [[SVG]] [[PCI]], without the use of [[embolic]] protection devices. They found that pretreatment with [[nitroprusside]] results in a lower magnitude and frequency of post-procedural cardiac [[enzyme]] elevation. Thus, it is important to consider [[nitroprusside]] use. | Zoghbi et al. conducted a study to investigate the role of pretreatment with [[nitroprusside]] before [[SVG]] intervention<ref name="pmid19182287">{{cite journal |author=Zoghbi GJ, Goyal M, Hage F, ''et al.'' |title=Pretreatment with nitroprusside for microcirculatory protection in saphenous vein graft interventions |journal=J Invasive Cardiol |volume=21 |issue=2 |pages=34–9 |year=2009 |month=February |pmid=19182287 |doi= |url=}}</ref>. They studied sixty-four consecutive patients with normal preprocedural cardiac [[enzymes]] that underwent [[SVG]] [[PCI]], without the use of [[embolic]] protection devices. They found that pretreatment with [[nitroprusside]] results in a lower magnitude and frequency of post-procedural cardiac [[enzyme]] elevation. Thus, it is important to consider [[nitroprusside]] use. | ||
Finally, while [[Glycoprotein IIb/IIIa inhibitors|GP IIb/IIIa inhibitors]] are frequently used in the setting of [[SVG]] intervention, their benefit has not been fully evaluated in randomized trials of this lesion subset. | Finally, while [[Glycoprotein IIb/IIIa inhibitors|GP IIb/IIIa inhibitors]] are frequently used in the setting of [[SVG]] intervention, their benefit has not been fully evaluated in randomized trials of this lesion subset. | ||
===Complications of SVG PCI=== | ===Complications of SVG PCI=== | ||
Risk factors for complications include: | Risk factors for complications include: | ||
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As mentioned above, prevention of [[no reflow]] should be attempted with [[embolic]] protection devices, pretreatment using [[nitroprusside]] or [[verapamil]] and the avoidance of high-pressure inflations and unnecessary pre/post-dilation and oversizing. However, in the event that [[no reflow]] develops, it should be aggressively managed with intracoronary [[vasodilators]] (i.e. [[diltiazem]], [[nicardipine]], [[adenosine]], and [[nitroprusside]]). | As mentioned above, prevention of [[no reflow]] should be attempted with [[embolic]] protection devices, pretreatment using [[nitroprusside]] or [[verapamil]] and the avoidance of high-pressure inflations and unnecessary pre/post-dilation and oversizing. However, in the event that [[no reflow]] develops, it should be aggressively managed with intracoronary [[vasodilators]] (i.e. [[diltiazem]], [[nicardipine]], [[adenosine]], and [[nitroprusside]]). | ||
==Follow Up Care== | ==Follow Up Care== | ||
Regardless of treatment choice, all patients should be given [[statins]] and [[aspirin]] (begun immediately following [[CABG]]), which are effective in the secondary prevention of [[SVG]] [[stenosis]]. | Regardless of treatment choice, all patients should be given [[statins]] and [[aspirin]] (begun immediately following [[CABG]]), which are effective in the secondary prevention of [[SVG]] [[stenosis]]. | ||
==2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (DO NOT EDIT)<ref name="pmid22070837">{{cite journal |author=Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH |title=2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions |journal=[[Journal of the American College of Cardiology]] |volume=58 |issue=24|pages=2550–83 |year=2011|month=December|pmid=22070837|doi=10.1016/j.jacc.2011.08.006|url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(11)02875-0|accessdate=2011-12-08|url=http://content.onlinejacc.org/cgi/reprint/58/24/2550.pdf|PDF}}</ref>== | |||
===Saphenous Vein Grafts (DO NOT EDIT)<ref name="pmid22070837">{{cite journal|author=Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH |title=2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions |journal=[[Journal of the American College of Cardiology]]|volume=58 |issue=24 |pages=2550–83|year=2011|month=December|pmid=22070837|doi=10.1016/j.jacc.2011.08.006|url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(11)02875-0|accessdate=2011-12-08|url=http://content.onlinejacc.org/cgi/reprint/58/24/2550.pdf|PDF}}</ref>=== | |||
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| colspan="1" style="text-align:center; background:LightGreen"|[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class I]] | |||
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| bgcolor="LightGreen"|<nowiki>"</nowiki>'''1.''' Embolic protection devices should be used during [[saphenous vein graft|saphenous vein graft PCI]] when technically feasible.<ref name="pmid11901037">{{cite journal |author=Baim DS, Wahr D, George B, Leon MB, Greenberg J, Cutlip DE, Kaya U, Popma JJ, Ho KK, Kuntz RE |title=Randomized trial of a distal embolic protection device during percutaneous intervention of saphenous vein aorto-coronary bypass grafts |journal=[[Circulation]] |volume=105 |issue=11 |pages=1285–90|year=2002 |month=March |pmid=11901037 |doi=|url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=11901037 |accessdate=2011-12-15}}</ref><ref name="pmid18212287">{{cite journal|author=Coolong A, Baim DS, Kuntz RE, O'Malley AJ, Marulkar S, Cutlip DE, Popma JJ, Mauri L|title=Saphenous vein graft stenting and major adverse cardiac events: a predictive model derived from a pooled analysis of 3958 patients |journal=[[Circulation]] |volume=117 |issue=6|pages=790–7|year=2008 |month=February |pmid=18212287 |doi=10.1161/CIRCULATIONAHA.106.651232|url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=18212287|accessdate=2011-12-15}}</ref><ref name="pmid17919563">{{cite journal |author=Mauri L, Cox D, Hermiller J, Massaro J, Wahr J, Tay SW, Jonas M, Popma JJ, Pavliska J, Wahr D, Rogers C |title=The PROXIMAL trial: proximal protection during saphenous vein graft intervention using the Proxis Embolic Protection System: a randomized, prospective, multicenter clinical trial |journal=[[Journal of the American College of Cardiology]] |volume=50 |issue=15 |pages=1442–9 |year=2007 |month=October|pmid=17919563|doi=10.1016/j.jacc.2007.06.039|url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(07)02300-5|accessdate=2011-12-15}}</ref><ref name="pmid12874191">{{cite journal |author=Stone GW, Rogers C, Hermiller J, Feldman R, Hall P, Haber R, Masud A, Cambier P, Caputo RP, Turco M, Kovach R, Brodie B, Herrmann HC, Kuntz RE, Popma JJ, Ramee S, Cox DA |title=Randomized comparison of distal protection with a filter-based catheter and a balloon occlusion and aspiration system during percutaneous intervention of diseased saphenous vein aorto-coronary bypass grafts |journal=[[Circulation]]|volume=108 |issue=5 |pages=548–53 |year=2003 |month=August|pmid=12874191|doi=10.1161/01.CIR.0000080894.51311.0A |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=12874191|accessdate=2011-12-15}}</ref> ''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: B]])''<nowiki>"</nowiki> | |||
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|colspan="1" style="text-align:center; background:LightCoral"|[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class III]] (No Benefit) | |||
|- | |||
|bgcolor="LightCoral"|<nowiki>"</nowiki>'''1.''' [[Glycoprotein IIb/IIIa inhibitors|Platelet GP IIb/IIIa inhibitors]] are not beneficial as adjunctive therapy during [[saphenous vein graft|saphenous vein graft PCI]].<ref name="pmid17148711">{{cite journal |author=Eisenstein EL, Anstrom KJ, Kong DF, Shaw LK, Tuttle RH, Mark DB, Kramer JM, Harrington RA, Matchar DB, Kandzari DE, Peterson ED, Schulman KA, Califf RM|title=Clopidogrel use and long-term clinical outcomes after drug-eluting stent implantation|journal=[[JAMA : the Journal of the American Medical Association]] |volume=297 |issue=2|pages=159–68 |year=2007 |month=January |pmid=17148711|doi=10.1001/jama.297.2.joc60179|url=http://jama.ama-assn.org/cgi/pmidlookup?view=long&pmid=17148711|accessdate=2011-12-15}}</ref><ref name="pmid18534267">{{cite journal |author=Brar SS, Kim J, Brar SK, Zadegan R, Ree M, Liu IL, Mansukhani P, Aharonian V, Hyett R, Shen AY|title=Long-term outcomes by clopidogrel duration and stent type in a diabetic population with de novo coronary artery lesions|journal=[[Journal of the American College of Cardiology]] |volume=51 |issue=23 |pages=2220–7|year=2008 |month=June |pmid=18534267|doi=10.1016/j.jacc.2008.01.063|url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(08)01051-6|accessdate=2011-12-15}}</ref><ref name="pmid12473552">{{cite journal |author=Roffi M, Mukherjee D, Chew DP, Bhatt DL, Cho L, Robbins MA, Ziada KM, Brennan DM, Ellis SG, Topol EJ |title=Lack of benefit from intravenous platelet glycoprotein IIb/IIIa receptor inhibition as adjunctive treatment for percutaneous interventions of aortocoronary bypass grafts: a pooled analysis of five randomized clinical trials |journal=[[Circulation]] |volume=106|issue=24 |pages=3063–7 |year=2002|month=December |pmid=12473552 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=12473552|accessdate=2011-12-15}}</ref><ref name="pmid9822087">{{cite journal|author=Ellis SG, Lincoff AM, Miller D, Tcheng JE, Kleiman NS, Kereiakes D, Califf R, Topol EJ|title=Reduction in complications of angioplasty with abciximab occurs largely independently of baseline lesion morphology. EPIC and EPILOG Investigators. Evaluation of 7E3 for the Prevention of Ischemic Complications. Evaluation of PTCA To Improve Long-term Outcome with abciximab GPIIb/IIIa Receptor Blockade |journal=[[Journal of the American College of Cardiology]] |volume=32|issue=6|pages=1619–23 |year=1998 |month=November |pmid=9822087 |doi=|url=http://linkinghub.elsevier.com/retrieve/pii/S0735109798004033|accessdate=2011-12-15}}</ref>''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: B]])''<nowiki>"</nowiki> | |||
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|colspan="1" style="text-align:center; background:LightCoral"|[[ACC AHA guidelines classification scheme#Classification of Recommendations|Class III]] (Harm) | |||
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|bgcolor="LightCoral"|<nowiki>"</nowiki>'''1.''' PCI is not recommended for [[saphenous vein graft#Saphenous Vein Graft Failure and Patency|chronic saphenous vein graft occlusions]].<ref name="pmid21126616">{{cite journal|author=Al-Lamee R, Ielasi A, Latib A, Godino C, Ferraro M, Arioli F, Mussardo M, Piraino D, Figini F, Carlino M, Montorfano M, Chieffo A, Colombo A |title=Clinical and angiographic outcomes after percutaneous recanalization of chronic total saphenous vein graft occlusion using modern techniques|journal=[[The American Journal of Cardiology]] |volume=106 |issue=12 |pages=1721–7 |year=2010|month=December |pmid=21126616|doi=10.1016/j.amjcard.2010.08.013|url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9149(10)01616-4|accessdate=2011-12-15}}</ref><ref name="pmid2525867">{{cite journal |author=de Feyter PJ, Serruys P, van den Brand M, Meester H, Beatt K, Suryapranata H |title=Percutaneous transluminal angioplasty of a totally occluded venous bypass graft: a challenge that should be resisted |journal=[[The American Journal of Cardiology]] |volume=64 |issue=1 |pages=88–90 |year=1989 |month=July|pmid=2525867 |doi=|url=http://linkinghub.elsevier.com/retrieve/pii/0002-9149(89)90658-9|accessdate=2011-12-15}}</ref><ref name="pmid8496517">{{cite journal|author=de Feyter PJ, van Suylen RJ, de Jaegere PP, Topol EJ, Serruys PW |title=Balloon angioplasty for the treatment of lesions in saphenous vein bypass grafts |journal=[[Journal of the American College of Cardiology]]|volume=21 |issue=7 |pages=1539–49 |year=1993 |month=June|pmid=8496517 |doi=|url=http://linkinghub.elsevier.com/retrieve/pii/0735-1097(93)90366-9 |accessdate=2011-12-15}}</ref>''([[ACC AHA guidelines classification scheme#Level of Evidence|Level of Evidence: C]])''<nowiki>"</nowiki> | |||
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'''1 | |||
==Guideline Resources== | ==Guideline Resources== | ||
*[http://content.onlinejacc.org/cgi/reprint/58/24/2550.pdf 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions]<ref name="pmid22070837">{{cite journal |author=Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH |title=2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions |journal=[[Journal of the American College of Cardiology]] |volume=58 |issue=24 |pages=2550–83 |year=2011 |month=December |pmid=22070837 |doi=10.1016/j.jacc.2011.08.006 |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(11)02875-0 |accessdate=2011-12-08}}</ref> | *[http://content.onlinejacc.org/cgi/reprint/58/24/2550.pdf 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions]<ref name="pmid22070837">{{cite journal |author=Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH |title=2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions |journal=[[Journal of the American College of Cardiology]] |volume=58 |issue=24 |pages=2550–83 |year=2011 |month=December |pmid=22070837 |doi=10.1016/j.jacc.2011.08.006 |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(11)02875-0 |accessdate=2011-12-08}}</ref> | ||
==Related Chapters== | ==Related Chapters== | ||
*[[Percutaneous Coronary Intervention (PCI): Basic Principles and Guidelines]] | *[[Percutaneous Coronary Intervention (PCI): Basic Principles and Guidelines]] | ||
Latest revision as of 18:43, 5 November 2012
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Saphenous vein graft intervention is a high risk interventional cardiology procedure which is intended to improve flow in a partially obstructed saphenous vein graft which is anastomosed to a native coronary artery. Intervention in a totally occluded saphenous vein graft is a "tempatation best left avoided" given the potential for extensive embolization into the native circulation. Based upon the SAFER trial, percutaneous coronary intervention in a saphenous vein graft is usually performed in conjunction with distal protection to minimize the embolic potential. For most SVG lesions, PCI with stenting appears to be the therapy of choice. DES are associated with a decreased restenosis rate over BMS, and should be used preferentially if the patient is able to tolerate dual platelet therapy for a minimum of a year. Furthermore, embolic protection devices should be strongly considered for all SVG lesions, especially those with high risks for distal embolization. In cases in which stent delivery and expansion may be difficult due to heavily calcified and stenotic lesions, atherectomy devices, used with stenting, may be considered. Furthermore, these devices can be useful in lesions that are aorto-ostial.
Timing of SVG Intervention
The goal of SVG intervention is to perform it early on in the development of ischemia while the SVG is still patent. Although intervention on a chronic total occlusion of a SVG may seem like an effective treatment strategy, it is "a temptation best avoided". Indeed one of the goals of SVG intervention is to minimize embolic potential. Thus, at the earliest signs of recurrent ischemia, it is important to strongly consider the possibility of a patent but stenosed SVG, so that the graft lesion can be treated before the graft becomes completely occluded. Prompt treatment is essential, since a graft is lost once it becomes completely occluded.
Treatment Options
There are many different choices to consider when deciding the most appropriate treatment for SVG stenosis, including conventional balloon angioplasty (PTCA), PCI with bare metal or drug-eluting stents, PCI with covered stents, embolic protection devices, debulking/thrombus removal, and surgical revascularization.
Conventional Percutaneous Transluminal Coronary Angioplasty (PTCA) or (POBA)
PTCA has high initial revascularization success rates in the treatment of SVG stenosis. However, it is also associated with high rates of periprocedural complications, including acute vessel closure secondary to dissection and in-situ thrombosis. Additional complications include distal embolization and no reflow, which can lead to periprocedural infarction.
In modern interventional cardiology, PTCA is not often used as the sole means of treatment for SVG stenosis. Instead, stenting has become the cornerstone of treatment, while the use of PTCA has been limited to pre-dilation and post-dilation. An exception would be a scenario in which a stent cannot be advanced through the saphenous vein graft to the lesion.
PCI with Bare Metal Stents (BMS) or Drug-eluting Stents (DES)
Most current vein graft treatment strategies utilize PCI with stents (BMS or DES), since stenting is a superior treatment when compared to PTCA alone. As demonstrated in the SAVED (Saphenous Vein De Novo) Trial[1], the use of stents is associated with higher revascularization success rates, decreased restenosis rates, and improved clinical outcomes when compared to PTCA. Generally, DES are preferred over BMS, since DES are associated with reduced rates of restenosis and target vessel revascularization.
Despite their higher success rates, stents are not immune to restenosis. Predictors for restenosis include long stent length, multiple stents, overlapping stents, smaller vessel size, diabetes mellitus, and stenosis at the coronary or aortic anastomosis.
PCI with Covered Stents
Theoretically, stents covered with a polymer membrane would have higher success rates than standard BMS and DES. One would expect covered stents to effectively trap friable atheroma and isolate the graft lumen from the diseased wall, thereby reducing incidence of restenosis, distal embolization, and no reflow in comparison to traditional stents. However, the RECOVERS (The Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts)[2] and STING (STents IN Grafts)[3] trials did not show any advantage in using covered stents when compared to bare metal stents for SVG lesions.
Embolic Protection Devices
During PCI of SVGs, atheroembolic debris can be liberated. This debris contains vasoactive substances that can contribute to no reflow, which can in turn considerably increase the risk of major adverse clinical events (MACE)[4]. Fortunately, embolic protection devices help capture this debris and improve outcomes in PCI for SVG stenosis. Therefore, it is recommended that these devices should be utilized in the intervention of most SVG lesions.
Currently, the FDA has approved five embolic protection devices in the United States. Specifically, these devices include one distal occlusion device, three filters, and one proximal occlusion device.
The FDA-approved distal occlusion device is called the PercuSurge Guardwire®, which involves inflating a balloon distal to the stenosis to occlude flow, thereby trapping the debris and vasoactive substances and preventing them from flowing downstream. Due to its small size, it requires little landing zone to deploy. The SAFER (Saphenous vein graft Angioplasty Free of Emboli Randomized) trial[5] showed that when compared to conventional guidewires, balloon occlusion devices (PercuSurge Guardwire®) reduced the rates of infarction and no-reflow after intervention. Despite these advantages, the PercuSurge Guardwire® may not be the best option for all, as some patients may not tolerate the necessary 3-5 minutes of ischemic time associated with this device. Additionally, it is known to cause both hemodynamic and arrhythmic complications.
Filter devices allow continual distal perfusion while macroscopic emboli are trapped in the filter. The FIRE (FilterWire EX During Transluminal Intervention of Saphenous Vein Grafts) trial[6][7] showed that FilterWire may be preferred over PercuSurge Guardwire® due to improved clinical outcomes. While they may reduce ischemic time, filter devices are associated with their own set of potential complications. They are more difficult to deliver than balloon occlusion devices, so their own delivery may lead to distal embolization, and they may not trap microscopic mediators of no reflow. Additionally, they require a significant landing zone distal to the lesion for the filter placement, which can be problematic for certain distal lesions that do not have enough room. There have also been case reports of filter entrapment in the graft after the completion of the PCI.
The FDA-approved proximal occlusion device is called the Proxis® device. Some advantages of this decide are that its deployment does not require crossing the stenosis, it provides superior support that is helpful where balloon or stent delivery is difficult, and it provides protected crossing of the lesion, if required. However, as shown by the PROXIMAL (Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System) trial[8], in terms of overall outcomes, there is no significant difference in death, MI, or target vessel revascularization (TVR) between distal and proximal embolic protection devices.
Debulking/Thrombus Removal
Data has not demonstrated a durable clinical benefit associated with debulking/thrombus removal. However, there are certain situations in which debulking techniques may be useful when treating saphenous vein grafts. For instance, severely calcified and stenotic lesions can make regular stent insertion especially difficult. When SVG lesions are too calcified to be crossed by a balloon or adequately dilated prior to stent placement, debulking and thrombus removal can change the compliance of the vessel wall. In addition, this technique is also useful if a lesion is at the aorto-ostial junction. Adjunctive stenting leads to better short and long term results.
There are several debulking/thrombus removal techniques, including directional coronary atherectomy, transluminal extraction catheter thrombectomy, rotational atherectomy, and laser atherectomy.
- Directional coronary atherectomy (DCA) uses a circular cutting blade that excises atheroma into a chamber for removal. It is useful for aorto-ostial lesions and focal lesions in large vessels. However, due to its bulky nature, it is generally not used in vessels with angulation, tortuosity, or heavy calcification. CAVEAT II (Coronary Angioplasty Versus Excisional Atherectomy Trial)[9] examined how PTCA and DCA compared in the treatment of patients with coronary artery bypass graft stenoses. This study demonstrated that DCA was associated with higher initial angiographic success rates and larger acute luminal dimensions in comparison to PTCA. However, despite these successes, DCA also displayed an increased rate of non-Q wave myocardial infusion and distal embolization than PTCA. Furthermore, both techniques displayed similar restenosis rates.
- Additionally, a retrospective study compared DCA vs. PTCA alone vs. PCI with stenting in SVG lesions. It showed no differences in mortality, angina, infarction, or repeat revascularization among the different methods. However, this study displayed increased angiographic complications with DCA use.
- Transluminal extraction catheter (TEC) thrombectomy is designed to remove thrombus from SVGs prior to stenting. It operates through the use of cutting blades with a rotating catheter and an external suction device. However, because the TEC Best trial showed no benefit of TEC prior to the stenting of SVGs, this technique has fallen out of favor. Furthermore, TEC is also associated with a significant incidence of distal embolization and no reflow.
- Rotational atherectomy (RA) uses a rotating cutting blade to grind calcified atheroma. Despite its ability to grind calcification, this method is associated with high rates of no reflow, distal embolization, perforation, and dissection. Furthermore, this method is contraindicated for lesions located in the body of SVGs or in degenerated vein grafts.
- Laser atherectomy uses monochromatic light energy to disrupt plaques. Despite this approach's innovation, there is no evidence that this strategy improves outcomes in lesions, and it has been complicated by high rates of dissection and perforation.
Surgical Revascularization
Given increased perioperative mortality in a "re-do" case, surgical revascularization is not an optimal treatment strategy, as many patients with graft disease are poor surgical candidates. However, surgery may be required in patients with multi-vessel disease and when PCI fails.
It should also be noted that reoperation often does not provide the same level of revascularization and resolution of angina as the initial procedure. Furthermore, a LIMA may be jeopardized in a reoperation.
Adjunctive Pharmacotherapy
Zoghbi et al. conducted a study to investigate the role of pretreatment with nitroprusside before SVG intervention[10]. They studied sixty-four consecutive patients with normal preprocedural cardiac enzymes that underwent SVG PCI, without the use of embolic protection devices. They found that pretreatment with nitroprusside results in a lower magnitude and frequency of post-procedural cardiac enzyme elevation. Thus, it is important to consider nitroprusside use.
Finally, while GP IIb/IIIa inhibitors are frequently used in the setting of SVG intervention, their benefit has not been fully evaluated in randomized trials of this lesion subset.
Complications of SVG PCI
Risk factors for complications include:
Although PCI with stenting is effective for focal lesions, there is uncertainty regarding the best treatment for diffusely degenerated SVGs. In these cases, it is often a better choice to abandon the graft and intervene on the native vessel instead.
As mentioned above, prevention of no reflow should be attempted with embolic protection devices, pretreatment using nitroprusside or verapamil and the avoidance of high-pressure inflations and unnecessary pre/post-dilation and oversizing. However, in the event that no reflow develops, it should be aggressively managed with intracoronary vasodilators (i.e. diltiazem, nicardipine, adenosine, and nitroprusside).
Follow Up Care
Regardless of treatment choice, all patients should be given statins and aspirin (begun immediately following CABG), which are effective in the secondary prevention of SVG stenosis.
2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (DO NOT EDIT)[11]
Saphenous Vein Grafts (DO NOT EDIT)[11]
| Class I |
| "1. Embolic protection devices should be used during saphenous vein graft PCI when technically feasible.[5][12][8][6] (Level of Evidence: B)" |
| Class III (No Benefit) |
| "1. Platelet GP IIb/IIIa inhibitors are not beneficial as adjunctive therapy during saphenous vein graft PCI.[13][14][15][16](Level of Evidence: B)" |
| Class III (Harm) |
| "1. PCI is not recommended for chronic saphenous vein graft occlusions.[17][18][19](Level of Evidence: C)" |
Guideline Resources
- 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions[11]
Related Chapters
References
- ↑ Savage MP, Douglas JS, Fischman DL; et al. (1997). "Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators". N. Engl. J. Med. 337 (11): 740–7. PMID 9287229. Unknown parameter
|month=ignored (help) - ↑ Stankovic G, Colombo A, Presbitero P; et al. (2003). "Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial". Circulation. 108 (1): 37–42. doi:10.1161/01.CIR.0000079106.71097.1C. PMID 12821546. Unknown parameter
|month=ignored (help) - ↑ Schächinger V, Hamm CW, Münzel T; et al. (2003). "A randomized trial of polytetrafluoroethylene-membrane-covered stents compared with conventional stents in aortocoronary saphenous vein grafts". J. Am. Coll. Cardiol. 42 (8): 1360–9. PMID 14563575. Unknown parameter
|month=ignored (help) - ↑ Salloum J, Tharpe C, Vaughan D, Zhao DX (2005). "Release and elimination of soluble vasoactive factors during percutaneous coronary intervention of saphenous vein grafts: analysis using the PercuSurge GuardWire distal protection device". J Invasive Cardiol. 17 (11): 575–9. PMID 16264199. Unknown parameter
|month=ignored (help) - ↑ 5.0 5.1 Baim DS, Wahr D, George B; et al. (2002). "Randomized trial of a distal embolic protection device during percutaneous intervention of saphenous vein aorto-coronary bypass grafts". Circulation. 105 (11): 1285–90. PMID 11901037. Unknown parameter
|month=ignored (help) - ↑ 6.0 6.1 Stone GW, Rogers C, Hermiller J; et al. (2003). "Randomized comparison of distal protection with a filter-based catheter and a balloon occlusion and aspiration system during percutaneous intervention of diseased saphenous vein aorto-coronary bypass grafts". Circulation. 108 (5): 548–53. doi:10.1161/01.CIR.0000080894.51311.0A. PMID 12874191. Unknown parameter
|month=ignored (help) - ↑ Halkin A, Masud AZ, Rogers C; et al. (2006). "Six-month outcomes after percutaneous intervention for lesions in aortocoronary saphenous vein grafts using distal protection devices: results from the FIRE trial". Am. Heart J. 151 (4): 915.e1–7. doi:10.1016/j.ahj.2005.09.018. PMID 16569562. Unknown parameter
|month=ignored (help) - ↑ 8.0 8.1 Mauri L, Cox D, Hermiller J; et al. (2007). "The PROXIMAL trial: proximal protection during saphenous vein graft intervention using the Proxis Embolic Protection System: a randomized, prospective, multicenter clinical trial". J. Am. Coll. Cardiol. 50 (15): 1442–9. doi:10.1016/j.jacc.2007.06.039. PMID 17919563. Unknown parameter
|month=ignored (help) - ↑ Holmes DR, Topol EJ, Califf RM; et al. (1995). "A multicenter, randomized trial of coronary angioplasty versus directional atherectomy for patients with saphenous vein bypass graft lesions. CAVEAT-II Investigators". Circulation. 91 (7): 1966–74. PMID 7895354. Unknown parameter
|month=ignored (help) - ↑ Zoghbi GJ, Goyal M, Hage F; et al. (2009). "Pretreatment with nitroprusside for microcirculatory protection in saphenous vein graft interventions". J Invasive Cardiol. 21 (2): 34–9. PMID 19182287. Unknown parameter
|month=ignored (help) - ↑ 11.0 11.1 11.2 Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH (2011). "2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention: Executive Summary A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions" (PDF). Journal of the American College of Cardiology. 58 (24): 2550–83. doi:10.1016/j.jacc.2011.08.006. PMID 22070837. Retrieved 2011-12-08. Text "PDF" ignored (help); Unknown parameter
|month=ignored (help) - ↑ Coolong A, Baim DS, Kuntz RE, O'Malley AJ, Marulkar S, Cutlip DE, Popma JJ, Mauri L (2008). "Saphenous vein graft stenting and major adverse cardiac events: a predictive model derived from a pooled analysis of 3958 patients". Circulation. 117 (6): 790–7. doi:10.1161/CIRCULATIONAHA.106.651232. PMID 18212287. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ Eisenstein EL, Anstrom KJ, Kong DF, Shaw LK, Tuttle RH, Mark DB, Kramer JM, Harrington RA, Matchar DB, Kandzari DE, Peterson ED, Schulman KA, Califf RM (2007). "Clopidogrel use and long-term clinical outcomes after drug-eluting stent implantation". JAMA : the Journal of the American Medical Association. 297 (2): 159–68. doi:10.1001/jama.297.2.joc60179. PMID 17148711. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ Brar SS, Kim J, Brar SK, Zadegan R, Ree M, Liu IL, Mansukhani P, Aharonian V, Hyett R, Shen AY (2008). "Long-term outcomes by clopidogrel duration and stent type in a diabetic population with de novo coronary artery lesions". Journal of the American College of Cardiology. 51 (23): 2220–7. doi:10.1016/j.jacc.2008.01.063. PMID 18534267. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ Roffi M, Mukherjee D, Chew DP, Bhatt DL, Cho L, Robbins MA, Ziada KM, Brennan DM, Ellis SG, Topol EJ (2002). "Lack of benefit from intravenous platelet glycoprotein IIb/IIIa receptor inhibition as adjunctive treatment for percutaneous interventions of aortocoronary bypass grafts: a pooled analysis of five randomized clinical trials". Circulation. 106 (24): 3063–7. PMID 12473552. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ Ellis SG, Lincoff AM, Miller D, Tcheng JE, Kleiman NS, Kereiakes D, Califf R, Topol EJ (1998). "Reduction in complications of angioplasty with abciximab occurs largely independently of baseline lesion morphology. EPIC and EPILOG Investigators. Evaluation of 7E3 for the Prevention of Ischemic Complications. Evaluation of PTCA To Improve Long-term Outcome with abciximab GPIIb/IIIa Receptor Blockade". Journal of the American College of Cardiology. 32 (6): 1619–23. PMID 9822087. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ Al-Lamee R, Ielasi A, Latib A, Godino C, Ferraro M, Arioli F, Mussardo M, Piraino D, Figini F, Carlino M, Montorfano M, Chieffo A, Colombo A (2010). "Clinical and angiographic outcomes after percutaneous recanalization of chronic total saphenous vein graft occlusion using modern techniques". The American Journal of Cardiology. 106 (12): 1721–7. doi:10.1016/j.amjcard.2010.08.013. PMID 21126616. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ de Feyter PJ, Serruys P, van den Brand M, Meester H, Beatt K, Suryapranata H (1989). "Percutaneous transluminal angioplasty of a totally occluded venous bypass graft: a challenge that should be resisted". The American Journal of Cardiology. 64 (1): 88–90. PMID 2525867. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help) - ↑ de Feyter PJ, van Suylen RJ, de Jaegere PP, Topol EJ, Serruys PW (1993). "Balloon angioplasty for the treatment of lesions in saphenous vein bypass grafts". Journal of the American College of Cardiology. 21 (7): 1539–49. PMID 8496517. Retrieved 2011-12-15. Unknown parameter
|month=ignored (help)