Saphenous Vein Graft Intervention Research Articles

Long-term histological and immunohistochemical findings in human venous aorto-coronary bypass grafts

The aim of the present study was to analyse the long-term histology and immunohistochemistry of the plaque composition and cellular infiltration of SVGs (saphenous vein grafts) containing metallic stents. Percutaneous interventions in SVGs have a worse long-term clinical outcome compared with stenting of coronary arteries. Whether the pathological features of old degenerated SVGs condition the efficacy of drug-eluting stents is also unknown. Histology and immunohistochemistry of seven SVGs in the coronary circulation containing 12 metallic stents implanted 5 to 61 months before retrieval were analysed in patients undergoing a second aorto-coronary bypass surgery at a mean time of 11+/-6 years. The pathology of the old SVGs showed an important thrombotic and necrotic composition of the plaque, with plaque protrusion through the stent wires and a fragile media layer that could easily be damaged by stent placement with subsequent neointimal proliferation; indeed, stents with medial fracture had significantly greater mean neointimal thickness than those without (1.37+/-0.68 compared with 0.81+/-0.47 mm(2); P<0.02). Neointimal inflammatory cell density correlated with increased neointimal thickness in patent vessels (r(2)=0.43, P<0.001). Immunostaining showed the total absence of ERs (oestrogen receptors), a poor cellular proliferative state as indicated by the presence of the Ki-67 marker, and persistent inflammation close to the stent wires as revealed by KP-1 and ACE (angiotensin-converting enzyme) immunostaining in most inflammatory cells in contact with the metal. These pathological findings may contribute to the more severe progression of disease and worse clinical outcome observed after conventional stented angioplasty of SVGs and might also interfere with the efficacy of drug-eluting stents in this specific atherosclerotic milieu.

The pathogenesis and treatment of no-reflow occurring during percutaneous coronary intervention

No-reflow is one of the major causes of postinterventional rise of cardiac enzyme and myocardial infarction (MI). This complication is associated with substantial morbidity and mortality after percutaneous coronary intervention (PCI). During and after a no-reflow episode, the patient can suffer from severe chest pain, hypotension, bradycardia, hemodynamic collapse, MI, congestive heart failure, and death. Every effort should be taken to reduce the incidence of this complication. The distal embolic protection device has been shown to decrease this risk in saphenous vein graft (SVG) interventions but not in native coronaries. On the other hand, the use of glycoprotein IIb/IIIa receptor antagonists have been effective in reducing the occurrence of no-reflow during PCI of native coronaries but not during SVG interventions. The treatment of no-reflow is based on the intracoronary administrations of medications that induce maximal vasodilatation in small distal coronary vasculature. The most commonly used drugs in this setting are adenosine, nitroprusside, and verapamil. The goal of this study was to review the pathogenesis and treatment of no-reflow in patients undergoing PCI.

Impacto dos stents de nova geração no tratamento de enxertos venosos aortocoronários - comparação angiográfica e ultra-sonográfica de duas séries first-in-human: MGuard® vs. SESAME®

FUNDAMENTO: As intervencoes percutâneas em pontes de safena (PS) apresentam menores taxas de sucesso angiografico e maior risco de complicacoes, pelo risco aumentado de embolizacao dos fragmentos da placa aterosclerotica friavel. Com o advento dos dispositivos de protecao distal, observou-se maior eficacia e seguranca do procedimento. Nosso objetivo foi comparar os stents MGuard® e SESAME®, dedicados ao tratamento de PS, nos primeiros 30 dias de evolucao. METODO: Estudo retrospectivo, comparando as variaveis angiograficas e ultra-sonograficas e a evolucao clinica aos 30 dias de pacientes portadores de lesoes em PS tratados com stent balao-expansivel MGuard® (n = 11) vs. stent auto-expansivel SESAME® (n = 14). RESULTADOS: Os pacientes tratados com stents MGuard® e SESAME® demonstraram perfis clinicos superponiveis (media de idade, 69 anos; sexo masculino, 72%; diabeticos, 28%; tratados na vigencia de sindrome coronaria aguda, 44%), idade dos enxertos venosos aortocoronarios equivalentes (9,7 ± 6,2 anos vs. 10,1 ± 3,2 anos; p = 0,80) e PS com o mesmo grau de acometimento aterosclerotico. O sucesso angiografico pos-procedimento foi alcancado em todos os casos, porem com tendencia a melhor expansao do stent no grupo MGuard® (87% vs. 68%; p = 0,08). No seguimento clinico de 30 dias, os pacientes tratados com stent SESAME® apresentaram maior frequencia de eventos cardiacos maiores (dois casos de infarto do miocardio nao-Q e um caso de revascularizacao do vaso-alvo), comparativamente a nenhum evento no grupo MGuard®. CONCLUSOES: Nessa analise retrospectiva de pequena serie de pacientes pre-selecionados de duas series first-in-human, o stent balao-expansivel MGuard® mostrou-se superior ao stent auto-expansivel SESAME® nos primeiros 30 dias de acompanhamento clinico.

Flow Impairment During Saphenous Vein Graft Intervention is Associated With Greater Plaque Embolization Despite Use of Distal Protection Device

Backgroundandaims:Saphenousveingraft percutaneous coronary intervention (SVG-PCI) has a 10–30% risk of myocardial infarction (AMI) by the ‘slow or no-reflow’ phenomenon. This is partly mediated by the embolization of atheromatous material. We sought to identify factors associated with reduced flow as assessed by TIMI frame count (TFC) post SVG-PCI. Methods: Consecutive patients (n= 24, age 68± 9) undergoing SVG-PCI utilizing the distal protection device, FilterWire EZ (Boston Scientific, Natick, MA) were enrolled. Quantitative coronary analysis (QCA) and TFC were performed on all angiograms by two cardiologists. We evaluated patients in two groups defined as improved or impaired TFC post-procedure. Results:Themean age of SVGwas 14.4 (±4.4) years. A total of 26 lesions were analysed with a mean lesion length of 23.3 (±17.9) mm. The inter-observer variability in TFCwas 2.3%. Increased TFC post-PCI, a marker of reduced flow, w a p r s t F l g C u i fl s b

Embolic Tendency of Non-Calcified Plaques During Saphenous Vein Graft Intervention: Utility of Multi-Detector Computed Tomography

Embolic Tendency of Non-Calcified Plaques During Saphenous Vein Graft Intervention: Utility of Multi-Detector Computed Tomography

Embolic protection: the FilterWire EZ™ Embolic Protection System

The field of interventional cardiology has grown dramatically over the past 30 years, including recent advances in the area of peripheral vascular intervention. The phenomenon of no-reflow, characterized by a reduction in coronary blood flow during vascular intervention, has been associated with adverse outcomes in both saphenous vein graft and carotid artery interventions. Distal embolic protection devices, such as the FilterWire EZ™ System, have been shown to reduce the incidence of no-reflow and adverse cardiac events in patients undergoing saphenous vein graft interventions. Recently approved indications for the FilterWire EZ System include carotid artery stenting. With the definite reduction in adverse events from the use of distal protection, future advancements will focus on improved deliverability of such devices.

Fourteen Month Follow-up Angioscopic Findings of a Sirolimus-Eluting Stent Implanted in a 15-Year-Old Saphenous Vein Graft

Saphenous vein grafts (SVGs) are common, as is their degeneration and early failure after coronary artery bypass graft surgery (CABG). Percutaneous SVG intervention with drug-eluting stents (DES) was associated with superior short-term clinical outcomes. However, SVG intervention compared with coronary intervention often results in distal embolisation and periprocedural myocardial infarction. In this case, we discuss 9 and 14 month follow-up neointimal coverage of a DES implanted in a 15 year-old SVG and other morphological changes using angioscopy.

Management of ‘no‐reflow’ complicating reperfusion therapy

No-reflow phenomenon, defined as inadequate myocardial perfusion of the adequately dilated target vessel without evidence of angiographic mechanical obstruction. It is a multifactorial, well-recognised, secondary phenomenon following reperfusion therapy such as thrombolysis or percutaneous coronary interventions (PCI). The pathophysiological mechanisms leading to the no-reflow state are incompletely understood. Embolization of the atheromatous material to the distal vasculature and intense arteriole vasospasm caused by microembolization of platelet-rich thrombi that release vasoactive agents resulting in microvascular obstructions are likely mechanisms. Current prophylaxis and management strategies are derived from limited clinical data. Intracoronary verapamil, adenosine and nitroprusside have been most frequently studied and administered for angiographic no-reflow during PCI for acute myocardial infarction or saphenous vein graft (SVG) lesions and have been shown to improve epicardial flow and microvascular perfusion. The use of distal embolic protection devices in SVG interventions also provide microvascular protection and improve clinical outcomes. However, by far the most important measures are prevention and anticipation during PCI as once no-reflow established, complete reversal of the situation may not be possible.

Short- and Long-Term Outcomes After Stent-Assisted Percutaneous Treatment of Saphenous Vein Grafts in the Drug-Eluting Stent Era

Percutaneous treatment of saphenous vein graft (SVG) lesions has been associated with higher rates of periprocedural complications and restenosis compared with non-SVG lesions. Whether these outcomes are similar in contemporary clinical practice, particularly when drug-eluting stents are used, is unknown. We evaluated outcomes of 110 consecutive patients who were treated with stent-assisted percutaneous coronary intervention for 145 SVG lesions (drug-eluting stents used in 91.0% of lesions). Embolic protection devices were used in 52.1% of treated grafts. Adverse events were recorded up to 1 year. Major or minor periprocedural myocardial necrosis occurred in 11 patients (10.9%). At 1-year clinical follow-up, we observed 13 myocardial infarctions (13.7%), 8 target lesion revascularizations (8.4%), 18 target vessel revascularizations (19.0%), 2 stent thromboses (2.1%), and 7 deaths (7.4%). The incidence of major adverse cardiac events, defined as death, myocardial infarction, or target vessel revascularization, was 30.5% at 1 year. By multivariable analysis, the presence of thrombus inside the graft before the procedure and the length of the stented segment were independent predictors of major adverse cardiac events at 1 year (hazard ratio for thrombus 4.07, 95% confidence interval 1.90 to 8.68, p = 0.0003; hazard ratio per millimeter of stented length 1.02, 95% confidence interval 1.01 to 1.03, p = 0.025). In conclusion, our data show that patients with SVG lesions remain a high-risk subgroup with worse outcomes after percutaneous coronary intervention compared with native vessel disease even in the era of drug-eluting stents.

Long‐Term Clinical Benefit of Sirolimus‐Eluting Stents Compared to Bare Metal Stents in the Treatment of Saphenous Vein Graft Disease

The purpose of this study was to evaluate the efficacy of sirolimus-eluting stents (SES) in the treatment of saphenous vein graft (SVG) disease. Percutaneous coronary intervention (PCI) of SVG lesions with bare metal stents (BMS) is associated with frequent in-stent restenosis, progression of disease in nonstented SVG segments, and suboptimal clinical outcomes. While SES have been shown to reduce restenosis rates in various native lesion subsets, the long-term clinical impact of SES use in SVG lesions is less clear. We compared our first 59 patients who underwent SES implantation in SVGs with 50 consecutive patients who received BMS in an equivalent time period prior to SES availability. Clinical outcomes were compared in both groups. Baseline clinical variables between the two groups were similar. Mean graft age in the SES cohort was older than that in the BMS cohort (12.9 years vs. 9.4 years). At follow-up, the SES group had a 24.6% absolute lower incidence of major adverse cardiac events (MACE) (25.4% vs. 50.0%), driven by a 20.7% absolute lower incidence of target vessel revascularization (TVR) (15.3% vs. 36.0%). The SES treatment group had a 24.1% lower rate of clinical restenosis (11.9% vs. 36.0%). The use of a SES was an independent negative predictor of MACE at a mean follow-up of 20 months (odds ratio [OR]= 0.48,P = 0.03). Despite the placement of longer stents in patients with older, smaller SVGs, the use of SES in the treatment of SVG lesions appears to be safe and is associated with less clinical restenosis and more favorable long-term clinical outcomes as compared with BMS.

Outcomes of Stent Thrombosis and Restenosis During Extended Follow-Up of Patients Treated With Bare-Metal Coronary Stents

Concern regarding risk of late thrombosis after "off-label" treatment with drug-eluting stents has prompted increased use of bare-metal stents (BMS) in current practice. The sequelae of late BMS failures, however, have been poorly characterized. We performed a retrospective study of 4503 consecutive patients treated with at least 1 BMS and dual antiplatelet therapy between 1994 and 2000. The cumulative incidence of stent thrombosis was 0.5% at 30 days (95% CI, 0.3% to 0.7%), 0.8% at 1 year (95% CI, 0.6% to 1.1%), and 2.0% at 10 years (95% CI, 1.5% to 2.5%). Risk of late (30 days to 1 year) and very late (>1 year) BMS thrombosis was increased among patients considered off label for drug-eluting stent use (P=0.024). When saphenous vein graft interventions were excluded, however, risk after off-label use was not significantly increased (P=0.23). Other correlates included vein graft intervention, prior myocardial infarction (MI), peripheral vascular disease, and ulcerated lesion (P<0.001). Mortality was markedly increased after late and very late BMS thrombosis, particularly during the first 30 days (hazard ratios, 22 [95% CI, 3.1 to 159] and 40 [95% CI, 15 to 107], respectively). The 10-year incidence of clinical restenosis was 18.1% (95% CI, 16.5% to 19.7%), presenting with MI in 2.1% (95% CI, 1.6% to 2.6%). Restenosis presenting with MI was associated with increased mortality compared with no restenosis (hazard ratio, 2.37; P<0.001) and with restenosis with a non-MI presentation (hazard ratio, 2.42; P<0.001). The incidence of BMS thrombosis and of MI caused by restenosis during extended follow-up is significant. Both complications are associated with mortality.

The PROXIMAL Trial: Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System: A Randomized, Prospective, Multicenter Clinical Trial

To determine if outcomes could be further improved, we investigated an embolic protection device placed proximal to the target lesion that could provide protection before lesion instrumentation, allow the use of conventional guidewires, and permit embolic protection in anatomy unfavorable for distal devices. Embolic complications during stenting of degenerated saphenous vein coronary bypass grafts are reduced, but not eliminated, by distal protection. A total of 594 patients undergoing stenting of 639 saphenous vein grafts were prospectively randomized, using a noninferiority design, to compare 2 treatment strategies: control (distal protection whenever possible) or test (proximal protection when possible, distal when not). The primary composite end point of death, myocardial infarction, or target vessel revascularization at 30 days by intention to treat analysis occurred in 10.0% of control and 9.2% of test patients; difference = -0.8% (95% confidence interval [CI] -5.5% to 4.0%); p for noninferiority = 0.0061. In device specific analysis, this composite end point occurred in 11.7% of distal protection patients and 7.1% of proximal protection patients (difference = -4.6% [95% CI -9.6% to 0.3%]; p for superiority = 0.10, p for noninferiority = 0.001). Finally, in the subset of patients with lesions amenable to treatment with either proximal or distal protection devices (n = 410), the primary composite end point occurred in 12.2% of distal protection patients and 7.4% of proximal protection patients; difference = -4.7% (95% CI -10.4% to 1.0%), p for superiority = 0.14, p for noninferiority = 0.001. Using proximal embolic protection whenever possible during treatment of diseased saphenous vein grafts produced outcomes similar to those with distal embolic protection.

Utilization of Distal Embolic Protection in Saphenous Vein Graft Interventions (An Analysis of 19,546 Patients in the American College of Cardiology–National Cardiovascular Data Registry)

In clinical trials, the use of a distal embolic protection device (EPD) during saphenous vein graft (SVG) percutaneous intervention (PCI) decreases the incidence of major adverse events. However, the frequency of EPD use during SVG PCI in clinical practice is unknown. We evaluated 19,546 SVG PCI procedures in the American College of Cardiology-National Cardiovascular Data Registry from January 1, 2004, through March 30, 2006. EPD use was the primary outcome. Univariate and multivariable analyses were used to assess for characteristics associated with EPD use and to determine the association between EPD use and 2 outcomes: no-reflow and in-hospital mortality. EPDs were used in 22% of patients who underwent SVG PCI. Characteristics independently associated with EPD use were age (odds ratio [OR] 1.04, p = 0.03), male gender (OR 1.12, p = 0.02), older grafts (p <0.001 for the group), longer lesions (OR 1.16, p <0.001), and American College of Cardiology/American Heart Association class C lesions (OR 1.41, p <0.001). Patients were less likely to receive an EPD if they had class <3 grade flow according to Thrombolysis in Myocardial Infarction classification (p <0.001) or previously treated lesions (OR 0.55, p <0.001). There was a weak correlation between annual hospital PCI volume and EPD use (r = 0.2, p <0.001). Nineteen percent of centers did not use EPDs and 41% used them in <10% of cases. EPD use was independently associated with a lower incidence of no-reflow (OR 0.68, p = 0.032), but not in-hospital mortality (1.0% vs 0.9%, p = NS). In conclusion, in current practice, EPDs are used in <25% of SVG PCI procedures.

Percutaneous coronary intervention and the no-reflow phenomenon

No-reflow during percutaneous coronary intervention (PCI) is observed most commonly during saphenous vein graft intervention, rotational atherectomy and primary PCI for acute ST-elevation myocardial infarction. The contributions of distal embolization and ischemia/reperfusion injury to the pathogenesis of no-reflow vary in these settings, as does prevention and management. Prevention of no-reflow in these high-risk groups is the best treatment strategy, employing antiplatelet agents, vasodilators and/or mechanical devices to prevent distal embolization. Once mechanical factors are excluded as a cause for reduced epicardial flow, the treatment of established no-reflow is mainly pharmacologic, since the obstruction occurs at the level of the microvasculature. Compared with patients in whom no-reflow is transient, refractory no-reflow is associated with a markedly increased risk of 30-day mortality.

Percutaneous coronary intervention in two occluded arms of a saphenous ‘Y’‐graft: The importance of protecting both of your arms

Percutaneous intervention in saphenous vein grafts (SVG) carries a higher risk of distal embolization than intervention in a native vessel, and use of a distal protection device has been shown to improve the outcomes in SVG interventions. We describe an intervention done in an unexpected 'Y' SVG which required dual distal protection with Filterwires placed in both limbs of the diseased graft and which was performed via a 6 Fr guide catheter.

The role of distal myocardial protection devices during percutaneous coronary interventions

The success of intervention and clinical outcome is markedly reduced in patients who sustain distal embolization during percutaneous coronary intervention (PCI). Such embolization occurs in up to 15% of patients with acute myocardial infarction (AMI) undergoing PCI, and angiographic indicators of embolization are highly predictive of clinical and functional outcome. Saphenous vein graft (SVG) interventions carry a 20% risk of major adverse cardiac events (MACE), predominantly AMI, and significant risk of no-reflow. There are four types of embolic protection: distal occlusion/aspiration systems, filters, proximal occlusion/aspiration devices, and thrombectomy catheters. There seem to be no data to suggest that routine use of any embolic protection system is beneficial in patients with ST-elevation myocardial infarction (STEMI) undergoing PCI. The message from both the EMERALD and PROMISE trials is that embolic protection does not improve perfusion in the setting of AMI. Although pretreatment with thrombus aspiration before PCI improves angiographic reperfusion rates compared with standard PCI, enzymatic release and early clinical outcomes are not improved. Although the clinical implications of routine thrombus aspiration have yet to be established, selective use may be justified in patients with the highest thrombus burden. In addition, it should be considered in those with acute stent thrombosis and elective use of filter-based protection considered in very high risk vessel PCI (eg, last remaining conduit). There is no easy way to anticipate which SVG intervention will result in embolization. In SVG intervention, both balloon occlusion/aspiration and filter-based distal protection devices have significantly reduced the incidence of 30-day MACE, driven by AMI and should, I believe, be used routinely. Risk of complications is low with all the established devices. The profile and deliverability are continuing to improve with newer devices. Cost-effectiveness of selective use in high-risk graft cases has only recently been demonstrated.

Bifurcating saphenous vein and left internal thoracic graft anatomy: Treatment of a left main equivalent saphenous interposition vein graft lesion and virtual histology/grey scale IVUS characterization post-intervention

Saphenous vein graft interventions carry a significant risk of adverse events. We present a case in which a free left internal thoracic artery (LITA to the LAD) had been anastomosed to a saphenous vein graft (SVG) to an obtuse marginal (OM) as its proximal anastomosis. Due to surgical iatrogenic injury during a subsequent aortic valve replacement, the proximal portion of this dual graft was resected in error and then repaired using an interposed vein graft (vein patch). We present the first known case of percutaneous intervention to an interposition vein graft stenosis with left main equivalent anatomy. Virtual histology (VH™) and grey scale intravascular ultrasound (IVUS) were utilized to visualize plaque characteristics in this novel lesion.

Prediction of Distal Embolization During Percutaneous Coronary Intervention in Saphenous Vein Grafts

Distal protection devices have been proved to decrease distal embolization and improve outcome in unselected patients undergoing percutaneous coronary intervention (PCI) in saphenous vein grafts (SVGs). However, it remains uncertain whether distal protection is necessary in all patients. We investigated whether clinical or angiographic variables can predict distal embolization and, hence, need for a distal protection device. Fifty-eight consecutive SVGs that underwent PCI with a FilterWire distal protection device were studied. After the procedure, the FilterWire was fixed in formalin and photographed, and embolic debris area (square millimeters) was quantified by semi-automated edge-detection analysis. Debris area was correlated with 6 prespecified variables: clinical presentation, SVG age, reference lumen diameter, plaque volume, SVG degeneracy, and presence of a filling defect. Embolic debris was identified in 57 of 58 grafts (98%). Median debris area was 4.0 mm(2) (range 0.0 to 25.1). None of the prespecified variables predicted the occurrence of distal embolization or the amount of captured embolic debris. In conclusion, distal embolization during SVG PCI is universal. Embolic burden cannot be predicted by clinical or angiographic variables, and embolic protection should be used in all patients.

Thrombus predicts ischemic complications during percutaneous coronary intervention in saphenous vein grafts: Results from TARGET (do tirofiban and reopro give similar efficacy trial?)

Saphenous vein graft (SVG) percutaneous coronary intervention (PCI) carries a high risk of ischemic complications. However, there are scant recent data to identify which SVG lesions carry particularly high risk in recent years. We studied demographic and angiographic factors associated with ischemic complications after SVG PCI without distal protection in the TARGET (do tirofiban and reopro give similar efficacy trial?) study. TARGET was a multicenter double-dummy, double-blinded study randomizing 4,809 PCI patients to tirofiban or abciximab. Of these, 254 patients underwent PCI involving an SVG lesion. The primary endpoint of this analysis was major adverse cardiac events (MACEs) at 30 days, including death, nonfatal myocardial infarction (MI), and urgent target vessel revascularization. No demographic characteristic was associated with 30-day MACE. Lesion length > 20 mm (odds ratio [OR] = 2.7, P = 0.03), thrombus (OR = 3.9, P = 0.003), eccentricity (P = 0.001), thrombolysis in myocardial infarction flow < 3 post-procedure (OR = 5.6, P = 0.037), and >1 target lesion (OR = 2.5, P = 0.035) were univariate variables associated with 30-day MACE. Multivariate analysis associated only thrombus (OR = 3.8, P = 0.015) with 30-day MACE. No difference in outcomes was noted between patients receiving abciximab and tirofiban. SVG patients had lesser angiographic success (95.6% vs. 98%, P = 0.04) and increased 30-day Q-wave MI (2.5% vs. 0.9%, P = 0.039) compared with non-SVG patients, but a similar incidence of death (0% vs. 0.4%), non-Q-MI (5.9% vs. 4.5%), and target vessel revascularization (0.5% vs. 1%). In the era of routine stenting and GpIIb/IIIa inhibitors, thrombus is the angiographic characteristic most closely associated with adverse outcomes of SVG PCI.

Response to Letter Regarding Article, “Impact of Internal Mammary Artery Conduit on Long-Term Outcomes After Percutaneous Intervention of Saphenous Vein Graft”

We thank Drs Brilakis and Banerjee for their insightful comments concerning our recently published study.1 Our goal was to evaluate whether percutaneous interventions of saphenous vein graft (SVG) had any influence on long-term outcomes. In accordance with the retrospective and observational nature of our study, we used currently accepted methodology that included adjustments using a Cox proportional hazard model to account for differences in baseline confounders in the 4 groups. In …