Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators

Outcome of Saphenous Vein Graft Percutaneous Coronary Intervention Using Contemporary Drug-Eluting Stents: A SCAAR Report

Background

Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVG) is associated with poor outcomes and is often regarded as inferior to native vessel PCI. We investigated clinical outcomes of SVG-PCI using contemporary drug-eluting stents (DES), in a complete, nationwide population.

Methods

The complete Swedish Coronary Angiography and Angioplasty Registry (SCAAR) was used to identify all patients in Sweden who underwent SVG-PCI with a contemporary DES between 2013 and 2020. Baseline characteristics, procedures, and outcomes were described.

Results

A total of 2198 SVG-PCI procedures with 3106 contemporary DES were included. Patients had a high incidence of comorbidities such as diabetes (40%), prior myocardial infarction (MI) (69%), and acute coronary syndrome (74%) at presentation. SVG-PCI procedures commonly involved multiple DES (41%). Native vessel PCI, in addition to SVG-PCI, was performed in only 13% of procedures. At 1 year, adverse clinical outcomes were frequent as exemplified by any death (9.2%), MI (9.1%), or revascularization (21.1%), whereas stent and lesion-related outcomes on a patient level were less common: stent thrombosis (1.2%), in-stent restenosis (4.3%) and target lesion revascularization (4.3%). Similarly, at 3 years, clinical outcomes were frequent: death (19.8%), MI (21.1%), revascularization (32.8%); and stent-related outcomes were less common: stent thrombosis (2.9%), restenosis (10.8), and target lesion revascularization (13.6%).

Conclusions

In this nationwide cohort of patients who underwent SVG-PCI with contemporary DES, patients were characterized by a high-risk profile and high rates of adverse clinical events. However, the incidence of stent and lesion-related events was low.

Pathophysiology and management of saphenous vein graft disease

INTRODUCTION

The saphenous vein graft (SVG) is the most used conduit in CABG. With standardization of its use as a conduit came an understanding of its accelerated atherosclerosis, known as saphenous vein graft disease (SVGD). Given its extensive use, a review of the pathophysiology and management of SVGD is important as we optimize its use.

AREAS COVERED

For this review, an extensive literature search was completed to identify and examine the evolution of SVG in CABG, mechanisms driving SVGD, and methods developed to prevent and manage it. This includes a review of relevant major papers and trials in this space.

EXPERT OPINION

Eras of evolution in SVG usage in CABG include an experimental era, era of SVG dominance in CABG, and the current era of mixed venous and arterial grafting. As SVGD was studied, the mechanisms behind it became more understood, and prevention and management methods were developed. As advances in surgical techniques and pharmacotherapy continue to reduce occurrence and severity of SVGD, long-term patency of SV grafts continues to improve and remain excellent in optimized settings. With continued innovation and improvement in operative techniques, the SVG conduit is and will remain an important player in the field of coronary bypass.

Contemporary coronary artery bypass graft surgery and subsequent percutaneous revascularization

Patients who have undergone coronary artery bypass graft (CABG) surgery are susceptible to bypass graft failure and progression of native coronary artery disease. Although the saphenous vein graft (SVG) was traditionally the most-used conduit, arterial grafts (including the left and right internal thoracic arteries and the radial artery) have improved patency rates. However, the need for secondary revascularization remains common, and percutaneous coronary intervention (PCI) has become the most common modality of secondary revascularization after CABG surgery. Procedural characteristics and clinical outcomes differ considerably from those associated with PCI in patients without previous CABG surgery, owing to altered coronary anatomy and differences in conduit pathophysiology. In particular, SVG PCI carries an increased risk of complications, and operators are shifting their focus towards embolic protection strategies and complex native-vessel interventions, increasingly using SVGs as conduits to facilitate native-vessel PCI rather than pursuing SVG PCI. In this Review, we discuss the differences in conduit pathophysiology, changes in CABG surgery techniques, and the latest evidence in terms of PCI in patients with previous CABG surgery, with a particular emphasis on safety and long-term efficacy. We explore the subject of contemporary CABG surgery and subsequent percutaneous revascularization in this complex patient population.

In-Stent Restenosis in Saphenous Vein Grafts (from the DIVA Trial)

Saphenous vein grafts (SVGs) have high rates of in-stent restenosis (ISR). We compared the baseline clinical and angiographic characteristics of patients and lesions that did develop ISR with those who did not develop ISR during a median follow-up of 2.7 years in the DIVA study (NCT01121224). We also examined the ISR types using the Mehran classification. ISR developed in 119 out of the 575 DIVA patients (21%), with similar incidence among patients with drug-eluting stents and bare-metal stents (BMS) (21% vs 21%, p = 0.957). Patients in the ISR group were younger (67 ± 7 vs 69 ± 8 years, p = 0.04) and less likely to have heart failure (27% vs 38%, p = 0.03) and SVG lesions with Thrombolysis In Myocardial Infarction 3 flow before the intervention (77% vs 83%, p <0.01), but had a higher number of target SVG lesions (1.33 ± 0.64 vs 1.16 ± 0.42, p <0.01), more stents implanted in the target SVG lesions (1.52 ± 0.80 vs 1.31 ± 0.66, p <0.01), and longer total stent length (31.37 ± 22.11 vs 25.64 ± 17.42 mm, p = 0.01). The incidence of diffuse ISR was similar in patients who received drug-eluting-stents and BMS (57% vs 54%, p = 0.94), but BMS patients were more likely to develop occlusive restenosis (17% vs 33%, p = 0.05).

Percutaneous coronary intervention of totally occluded coronary venous bypass grafts: An exercise in futility?

BACKGROUND

Percutaneous coronary intervention (PCI) of diseased saphenous vein grafts (SVG) continues to pose a clinical challenge. Current PCI guidelines give a class III recommendation against performing PCI on chronically occluded SVG. However, contemporary outcomes after SVG intervention have incrementally improved with distal protection devices, intracoronary vasodilators, drug-eluting stents, and prolonged dual antiplatelet therapy.

AIM

To reassess the procedural and long-term outcomes of PCI for totally occluded SVG with contemporary techniques.

METHODS

This was a retrospective observational study conducted at a single university hospital. The study population consisted of 35 consecutive patients undergoing PCI of totally occluded SVG. Post-procedure dual antiplatelet therapy was continued for a minimum of one year and aspirin was continued indefinitely. Clinical outcomes were assessed at a mean follow-up of 1221 ± 1038 d. The primary outcome was freedom from a major adverse cardiac event (MACE) defined as the occurrence of any of the following: death, myocardial infarction, stroke, repeat bypass surgery, repeat PCI, or graft reocclusion.

RESULTS

The study group included 29 men and 6 women with a mean age of 69 ± 12 years. Diabetes was present in 14 (40%) patients. All patients had Canadian Heart Classification class III or IV angina. Clinical presentation was an acute coronary syndrome in 34 (97%) patients. Mean SVG age was 12 ± 5 years. Estimated duration of occlusion was acute (< 24 h) in 34% of patients, subacute (> 24 h to 30 d) in 26%, and late (> 30 d) in 40%. PCI was initially successful in 29/35 SVG occlusions (83%). Total stent length was 52 ± 35 mm. Intraprocedural complications of distal embolization or no-reflow occurred in 6 (17%) patients. During longer term follow-up, MACE-free survival was only 30% at 3 years and 17% at 5 years.

CONCLUSION

PCI of totally occluded SVG can be performed with a high procedural success rate. However, its clinical utility remains limited by poor follow-up outcomes.

Mechanisms, Prevention and Treatment of Saphenous Vein Graft Disease

Saphenous vein grafts are imperfect yet indispensable conduits commonly used for coronary artery bypass grafting. Their degeneration ultimately leading to occlusion results from the pathological response of the vein to altered blood rheology and several types of vascular injury. Surgical techniques minimizing vessel damage, and prolonged antiplatelet and lipid-lowering treatment are established methods of mitigating the degeneration process hence preventing graft occlusions. Percutaneous interventions in degenerated vein grafts carry high risk of embolization, periprocedural myocardial infarction and restenosis. Thus, native vessel should be the preferred treatment target in case of graft failure whenever technically feasible.

Saphenous Vein Graft Failure: From Pathophysiology to Prevention and Treatment Strategies

Saphenous vein grafts (SVGs) remain the most frequently used conduits in coronary artery bypass graft surgery (CABG). Despite advances in surgical techniques and pharmacotherapy, SVG failure rates remain high, often leading to repeat coronary revascularization. The no-touch SVG harvesting technique (minimal graft manipulation with preservation of vasa vasorum and nerves) reduces the risk of SVG failure, whereas the effect of the off-pump technique on SVG patency remains unclear. Use of buffered storage solutions, intraoperative graft flow measurement, careful selection of the target vessels, and physiological assessment of the native coronary circulation before CABG may also reduce the incidence of SVG failure. Perioperative aspirin and high-intensity statin administration are the cornerstones of secondary prevention after CABG. Dual antiplatelet therapy is recommended for off-pump CABG and in patients with a recent acute coronary syndrome. Intermediate (30%-60%) SVG stenoses often progress rapidly. Stenting of intermediate SVG stenoses failed to improve outcomes; hence, treatment focuses on strict control of coronary artery disease risk factors. Redo CABG is associated with higher perioperative mortality compared with percutaneous coronary intervention (PCI); hence, the latter is preferred for most patients requiring repeat revascularization after CABG. SVG PCI is limited by high rates of no-reflow and a high incidence of restenosis during follow-up. Drug-eluting and bare metal stents provide similar long-term outcomes in SVG PCI. Embolic protection devices reduce no-reflow and should be used when feasible. PCI of the corresponding native coronary artery is associated with better short- and long-term outcomes and is preferred over SVG PCI, if technically feasible.

In-hospital outcomes and usage of embolic protection devices in percutaneous coronary intervention for coronary artery bypass grafts: Insights from a Japanese nationwide registry

OBJECTIVES

We evaluated the in-hospital outcomes of percutaneous coronary intervention (PCI) for bypass graft vessels (GV-PCI) compared with those of PCI for native vessels (NV-PCI) using data from the Japanese nationwide coronary intervention registry.

METHODS

We included PCI patients (N = 748,229) registered between January 2016 and December 2018 from 1,123 centers. We divided patients into three groups: GV-PCI (n = 2,745); NV-PCI with a prior coronary artery bypass graft (pCABG) (n = 23,932); and NV-PCI without pCABG (n = 721,552).

RESULTS

GV-PCI implementation was low, and most cases of PCI in pCABG patients were performed in native vessels (89.7%) in contemporary Japanese practice. The risk profile of patients with pCABG was higher than that of those without pCABG. Consequently, GV-PCI patients had a significantly higher in-hospital mortality than NV-PCI patients without pCABG after adjusting for covariates (odds ratio [OR] 2.36, 95% confidence interval [CI] 1.66-3.36, p < .001). Of note, embolic protection devices (EPDs) were used in 18% (n = 383) of PCIs for saphenous vein grafts (SVG-PCI) with a significant variation in its use among institutions (number of PCI: hospitals that had never used an EPD vs. EPD used one or more times = 240 vs. 345, p < .001). The EPDs used in the SVG-PCI group had a significantly lower prevalence of the slow-flow phenomenon after adjusting for covariates (OR 0.45, 95% CI 0.21-0.91, p = .04).

CONCLUSION

GV-PCI is associated with an increased risk of in-hospital mortality. EDP use in SVG-PCI was associated with a low rate of the slow-flow phenomenon. The usage of EPDs during SVG-PCI is low, with a significant variation among institutions.

Coronary Artery Bypass: Review of Surgical Techniques and Impact on Long-Term Revascularization Outcomes

Coronary revascularization for multivessel disease remains a common and costly source of hospitalizations in the United States. Surgical techniques influence outcomes for coronary bypass and also affect the need for percutaneous coronary intervention in the future. As more radial access has been used for coronary angiography, consideration for use of the radial artery as a surgical conduit remains unclear. Saphenous vein grafts are commonly used for coronary bypass, however long-term patency remains suboptimal, and is also associated with a higher risk of adverse events with percutaneous coronary intervention. Thus, understanding the interplay between coronary bypass techniques and percutaneous coronary intervention has become increasingly important.

Long-term outcomes of percutaneous coronary interventions within coronary artery bypass grafts

INTRODUCTION

The long-term outcomes of percutaneous coronary interventions (PCIs) within coronary artery bypasses are still poor as compared to those within native coronary arteries. Thus, we aimed to assess predictors of long-term clinical outcomes after PCIs of coronary bypasses.

MATERIAL AND METHODS

We enrolled 194 patients after PCIs of coronary artery bypasses at the mean age of 69.5 ±8.3 years (73.2% male). The primary study endpoint was a combination of target-vessel revascularization (TVR), target-lesion revascularization (TLR), myocardial infarction (MI), stroke, coronary artery bypass grafting (CABG) and death. The mean follow-up was 964 ±799.1 days and was completed among 156 patients. Multivariate analysis was used to assess determinants of study endpoints during follow-up. Moreover, we compared survival curves according to the type of PCI and presence of anti-embolic protection.

RESULTS

The primary endpoint of the study occurred in 59.7% of patients after the mean time of 669.6 ±598.7 days. The TVR occurred in 37.9% of individuals, TLR in 24.2%, MI in 26.3%, stroke in 4.2%, CABG in 2.1% and death in 30.5% of patients. In Cox multivariate analysis, PCI of two or more bypasses (p < 0.01), post-dilatation (p < 0.05) and no-reflow (p < 0.05) were the independent determinants of the primary study endpoint. No significant impact of anti-embolic protection devices on long-term outcomes was observed.

CONCLUSIONS

Percutaneous coronary interventions of two or more bypasses, post-dilatation and no-reflow are predictors of worse outcome in patients undergoing PCI within coronary artery bypass grafts.

Care of the Post-CABG Patient

An estimated 400,000 coronary artery bypass graft operations are performed annually in the United States. Saphenous vein grafts are the most commonly used conduits; however, graft failure is common. In contrast, left internal mammary artery grafts have more favorable long-term patency rates. Guidelines recommend aggressive secondary prevention. In the 2 decades following surgery, 16% of patients require repeat revascularization, and percutaneous coronary intervention accounts for 98% of procedures performed. Post-coronary artery bypass graft patients presenting with symptoms of acute coronary syndrome or progressive heart failure should undergo early coronary angiography given the high likelihood that such a presentation represents graft failure. Percutaneous coronary intervention in degenerated saphenous vein grafts is associated with embolization that may cause the "no-reflow phenomenon," which can be avoided with the use of embolic protection devices. Hybrid revascularization procedures are a promising emerging strategy to avoid the placement of vein grafts.

Drug-Eluting Stents Versus Bare-Metal Stents in Saphenous Vein Graft Intervention

Background Percutaneous coronary intervention with drug-eluting stents (DES) has been increasingly used for revascularization of saphenous vein graft stenosis without strong clinical evidence favoring their use. Randomized controlled trials comparing DES versus bare-metal stents (BMS) in saphenous vein graft-percutaneous coronary intervention have been inconclusive. Methods and Results We performed a comprehensive literature search through May 15, 2018, for all eligible studies comparing DES versus BMS in patients with saphenous vein graft stenosis in PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov. Clinical outcomes included all-cause mortality, cardiovascular mortality, major adverse cardiovascular events, myocardial infarction, stent thrombosis, and target vessel revascularization. Six randomized controlled trials were eligible and included 1582 patients, of whom 797 received DES and 785 received BMS. The follow-up period ranged from 18 months to 60 months. There was no statistically significant difference between DES and BMS for all-cause mortality (risk ratio [RR],1.11; 95% CI, 0.0.77-1.62; P=0.57), cardiovascular mortality (RR, 1.00; 95% CI, 0.64-1.57; P=0.99), major adverse cardiovascular events (RR, 0.83; 95% CI, 0.63-1.10; P=20), target vessel revascularization (RR, 0.73; 95% CI, 0.48-1.11; P=0.14), myocardial infarction (RR, 0.74; 95% CI, 0.48-1.16; P=0.19), or stent thrombosis (RR, 1.06; 95% CI, 0.42-2.65; P=0.90). Conclusions In patients undergoing percutaneous coronary intervention for saphenous vein graft lesions, our results showed that there was no significant difference between DES and BMS for mortality, major adverse cardiovascular events, target vessel revascularization, myocardial infarction, or stent thrombosis.

Internal mammary artery graft failure: Clinical features, management, and long-term outcomes

Objective

Data on long-term outcomes after internal mammary artery (IMA) coronary graft failure are scarce. Our objective was to describe the clinical characteristics, management, and prognosis after angiographically confirmed IMA graft failure following coronary revascularization.

Methods

A three-hospital retrospective registry, observational and descriptive, with prospective follow-up of all consecutive cases of IMA graft failure between 2004 and 2014 was conducted. After treatment, clinical and procedural features were compared between those with and without cardiovascular events.

Results

Fifty-seven patients were included (89% male, mean age: 62 years, at surgery) in the registry. Most patients underwent an IMA angioplasty (percutaneous coronary intervention [PCI], 74%). In nine cases, the PCI failed at the graft level, and seven underwent a native vessel revascularization. Native vessel treatment was performed in 20% of the study subjects, all with stents. Finally, medical management was decided in three cases. Events after treatment for IMA graft failure were frequent (50.8%), during a median follow-up of 7.5 years. Acute presentation (hazard ratio_MACE = 1.35; 95% confidence interval (CI): 1.12–3.00, p < 0.01), age of the patient (hazard ratio_MACE = 1.85, 95% CI: 1.17–2.11, p < 0.01), presence of diabetes mellitus (hazard ratio_MACE = 2.75, 95% CI: 1.13–6.69, p = 0.02), and the management modality used (IMA-simple angioplasty VS IMA-stenting: hazard ratio_MACE = 5.5, 95% CI: 1.40–21.15, p = 0.01) displayed prognostic relevance on multivariate analysis. All-cause mortality occurred in 21.1% and presentation as infarction (hazard ratio_DEATH = 1.05, 95% CI: 1.01–2.17, p = 0.01), age (hazard ratio_DEATH = 9.08, 95% CI: 2.52–32.69, p < 0.01), and left ventricular ejection fraction (hazard ratio_DEATH = 3.68, 95% CI: 1.65–8.18, p < 0.01) were independent predictors of the same.

Conclusions

In this long-term registry, most patients presented with an acute condition (myocardial infarction, progressive angina) within 12 months after surgery. Acute presentation, age, diabetes mellitus, reduced left ventricular ejection fraction, IMA graft failure segment affected, and the management strategy were related with long-term prognosis.

Predictors of periprocedural complications in patients undergoing percutaneous coronary interventions within coronary artery bypass grafts

BACKGROUND

During the first decade following the coronary bypass grafting, at least ten percent of the patients require percutaneous coronary interventions (PCI) due to graft failure. Saphenous vein grafts (SVG) are innately at a higher risk of periprocedural complications. The present study aimed to investigate predictors of periprocedural complications of PCI within coronary artery bypass grafts.

METHODS

This study analyzed data gathered in the Polish National Registry (ORPKI) between January 2015 and December 2016. Of the 221,195 patients undergoing PCI, data on 2,616 patients after PCI of SVG and 442 patients after internal mammary artery (IMA) were extracted. The dissimilarities in periprocedural complications between the SVG, IMA and non-IMA/SVG groups and their predictors were investigated.

RESULTS

Patients in the SVG group were older (p < 0.001), with a higher burden of concomitant disease and differing clinical presentation. The rate of de-novo lesions was lower, while restenosis was higher at baseline in the SVG (p < 0.001). The rate of no-reflows (p < 0.001), perforations (p = 0.01) and all periprocedural complications (p < 0.01) was higher in the SVG group, while deaths were lower (p < 0.001). Among the predictors of no-reflows, it was found that acute coronary syndromes (ACS), thrombectomy and past cerebral stroke, while the complications included arterial hypertension, Thrombolysis in Myocardial Infarction (TIMI) flow before PCI and thrombectomy.

CONCLUSIONS

Percutaneous coronary interventions of SVG is associated with increased risk of specific periprocedural complications. The ACS, slower TIMI flow before PCI and thrombectomy significantly increase the periprocedural complication rate in patients undergoing PCI of SVG.

Polymeric endovascular strut and lumen detection algorithm for intracoronary optical coherence tomography images

Polymeric endovascular implants are the next step in minimally invasive vascular interventions. As an alternative to traditional metallic drug-eluting stents, these often-erodible scaffolds present opportunities and challenges for patients and clinicians. Theoretically, as they resorb and are absorbed over time, they obviate the long-term complications of permanent implants, but in the short-term visualization and therefore positioning is problematic. Polymeric scaffolds can only be fully imaged using optical coherence tomography (OCT) imaging-they are relatively invisible via angiography-and segmentation of polymeric struts in OCT images is performed manually, a laborious and intractable procedure for large datasets. Traditional lumen detection methods using implant struts as boundary limits fail in images with polymeric implants. Therefore, it is necessary to develop an automated method to detect polymeric struts and luminal borders in OCT images; we present such a fully automated algorithm. Accuracy was validated using expert annotations on 1140 OCT images with a positive predictive value of 0.93 for strut detection and an R2 correlation coefficient of 0.94 between detected and expert-annotated lumen areas. The proposed algorithm allows for rapid, accurate, and automated detection of polymeric struts and the luminal border in OCT images.

Percutaneous Coronary Intervention of Saphenous Vein Graft

BACKGROUND

Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVGs) has historically been associated with a high risk of adverse ischemic events, but there is a paucity of contemporary data on the second-generation drug-eluting stent use within SVG, and the relative importance of high platelet reactivity (HPR) in SVG PCI versus native lesion PCI is unknown. We studied ischemic and bleeding events after SVG PCI and their association with HPR.

METHODS AND RESULTS

Subjects in the prospective, multicenter ADAPT-DES study (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) were stratified according to whether they had PCI of an SVG or a non-SVG lesion. Two-year outcomes were compared between groups using univariate and multivariable Cox proportional hazards models. HPR was defined as on-clopidogrel P2Y12 platelet reaction units >208 as measured by the VerifyNow assay; major adverse cardiac events were defined as the composite of cardiac death, myocardial infarction, or stent thrombosis. Among 8582 subjects in ADAPT-DES, 405 (4.7%) had SVG PCI. SVG PCI was independently associated with a higher 2-year risk of major adverse cardiac events (adjusted hazard ratio, 2.34; 95% confidence interval, 1.69-3.23; P<0.0001), ischemia-driven target vessel revascularization (adjusted hazard ratio, 1.82; 95% confidence interval, 1.37-2.42; P<0.0001), and stent thrombosis (adjusted hazard ratio, 2.26; 95% confidence interval, 1.42-3.59; P=0.0006), but not of bleeding (adjusted hazard ratio, 0.99; 95% confidence interval, 0.68-1.46; P=0.97). There was no statistical interaction between HPR and SVG PCI in regard to major adverse cardiac events (adjusted P_interaction=0.99).

CONCLUSIONS

SVG PCI is associated with a considerably higher risk of 2-year adverse ischemic events, with HPR conferring similar risk in SVG and non-SVG PCI. More potent and longer antiplatelet therapy may be beneficial for patients undergoing SVG PCI.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00638794.

Comparison between the STENTYS self-apposing bare metal and paclitaxel-eluting coronary stents for the treatment of saphenous vein grafts (ADEPT trial)

AIMS

To describe the safety and performance of STENTYS self-expandable bare metal stents (BMS) versus paclitaxel-eluting stents (PES) in saphenous vein grafts (SVGs).

METHODS AND RESULTS

A randomised controlled trial was performed in four hospitals in three European countries between December 2011 and December 2013. Patients with de novo lesions (>50% stenosis) in an SVG with a diameter between 2.5-6 mm were included. Primary endpoint was late lumen loss at 6 months. Secondary endpoints included procedural success and the occurrence of major adverse cardiac events (MACE) at 12 months. A total of 57 patients were randomised to STENTYS self-apposing BMS (n = 27) or PES (n = 30). Procedural success was obtained in 89.5%. No significant differences in late lumen loss were found between BMS and PES at 6 months (0.53 mm vs 0.47; p = 0.86). MACE rates at 12 months were comparable in both groups (BMS 22.2% vs. PES 26.7%; p = 0.70).

CONCLUSIONS

Treatment of SVGs with STENTYS self-expandable stents is safe and effective. No significant differences were found in late lumen loss and MACE between BMS and PES.

Current State of the Art in Approaches to Saphenous Vein Graft Interventions

Saphenous vein grafts (SVGs), used during coronary artery bypass graft surgery for severe coronary artery disease, are prone to degeneration and occlusion, leading to poor long-term patency compared with arterial grafts. Interventions used to treat SVG disease are susceptible to high rates of periprocedural MI and no-reflow. To minimise complications seen with these interventions, proper stents, embolic protection devices (EPDs) and pharmacological selection are crucial. Regarding stent selection, evidence has demonstrated superiority of drug-eluting stents over bare-metal stents in SVG intervention. The ACCF/AHA/SCA American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Society for Cardiovascular Angiography and Interventions guidelines recommend the use of EPDs during SVG intervention to decrease the risk of periprocedural MI, distal embolisation and no-reflow. The optimal pharmacological treatment for slow or no-reflow remains unclear, but various vasodilators show promise.

Management and Prevention of Saphenous Vein Graft Failure: A Review

Coronary artery bypass grafting (CABG) remains a vital treatment for patients with multivessel coronary artery disease (CAD), especially diabetics. The long-term benefit of the internal thoracic artery graft is well established and remains the gold standard for revascularization of severe CAD. It is not always possible to achieve complete revascularization through arterial grafts, necessitating the use of saphenous vein grafts (SVG). Unfortunately, SVGs do not have the same longevity, and their failure is associated with significant adverse cardiac outcomes and mortality. This paper reviews the pathogenesis of SVG failure, highlighting the difference between early, intermediate, and late failure. It also addresses the different surgical techniques that affect the incidence of SVG failure, as well as the medical and percutaneous prevention and treatment options in contemporary practice.

Ten Years of Advancements in Interventional Cardiology

The past decade has seen the evolution of an exciting technology that has changed forever the treatment of aortic aneurysmal disease. From rather crude homemade stent-grafts constructed in the surgical suite to elegant commercially manufactured devices in a variety of configurations and sizes, the aortic endograft has experienced a meteoric rise in popularity to become a beneficial, minimally invasive therapy that can obviate the risk of rupture and death. There are now 3 approved endovascular devices on the market for infrarenal abdominal aortic aneurysm repair, and it is likely that additional and improved devices will become available in the future. This review revisits the developmental history of the aortic endograft, noting the ongoing refinements that have arisen from our experiences with the growing population of stent-graft patients. Although research continues to search for solutions to the problems of endoleak and migration, long-term results even with the earlier second and third-generation devices are better than has been achieved with open surgical repair.

Drug-eluting versus bare metal stent in treatment of patients with saphenous vein graft disease: A meta-analysis of randomized controlled trials

Drug-eluting stent (DES) and bare metal stent (BMS) are effective treatments for preventing vascular disease, but whether using DES is associated with positive clinical outcomes compared with BMS in patients with saphenous vein graft disease (SVGD) has not been established. Three electronic databases including PubMed, EmBase, and the Cochrane Central Register of Controlled Trials were searched to identify potentially includible studies. We did a random-effects meta-analysis of randomized controlled trials (RCTs) to obtain summary effect estimates for the clinical outcomes with the use of relative risk calculated from the raw data of individual trial. Among 812 patients from 4 RCTs, DES was associated with lower risk of short-term major cardiovascular events (MACEs) when compared with BMS, whereas no significant effect on the risk of long-term MACEs. Furthermore, there was no significant difference between DES and BMS for short-term myocardial infarction (MI) and long-term MI. Similarly, DES was not associated with risk of short- and long-term mortality risk as compared with BMS. In addition, DES has no significant effect on the risk of cardiac death and stent thrombosis. Finally, DES therapy significantly reduced the risk of TLR, TVF, and TVR. SVGD patients received DES can minimize the risk of short-term MACEs, TLR, TVF, and TVR when compared with BMS. However, it does not effect on the incidence of long-term MACEs, MI, mortality, cardiac death, and stent thrombosis.

Vein graft failure: from pathophysiology to clinical outcomes

Occlusive arterial disease is a leading cause of morbidity and mortality worldwide. Aside from balloon angioplasty, bypass graft surgery is the most commonly performed revascularization technique for occlusive arterial disease. Coronary artery bypass graft surgery is performed in patients with left main coronary artery disease and three-vessel coronary disease, whereas peripheral artery bypass graft surgery is used to treat patients with late-stage peripheral artery occlusive disease. The great saphenous veins are commonly used conduits for surgical revascularization; however, they are associated with a high failure rate. Therefore, preservation of vein graft patency is essential for long-term surgical success. With the exception of 'no-touch' techniques and lipid-lowering and antiplatelet (aspirin) therapy, no intervention has hitherto unequivocally proven to be clinically effective in preventing vein graft failure. In this Review, we describe both preclinical and clinical studies evaluating the pathophysiology underlying vein graft failure, and the latest therapeutic options to improve patency for both coronary and peripheral grafts.

Second-generation versus first-generation drug-eluting stents in saphenous vein graftdisease: A meta-analysis of randomized controlled trials

BACKGROUND

Second-generation drug-eluting stents (DESs) have become increasingly popular devices for patients with saphenous vein graft (SVG) disease. Second-generation DESs were designed to have more safety and efficacy than first-generation DES, but clinical outcomes in SVG disease remain conflicting.

METHODS AND RESULTS

Randomized controlled trials (RCTs) were identified when comparing second- versus first-generation DESs in SVG disease. The main endpoint was all-cause death. The time of follow-up was at least 30days. The secondary endpoints were major adverse cardiovascular events (MACEs), target vessel revascularization (TVR), target lesion revascularization (TLR), myocardial infarction (MI), and stent thrombosis. These endpoints were assessed at 30days, 12months and 24months. Four RCTs with 1077 SVG patients undergoing the implantation of DES were collected in the current meta-analysis. As a result, second-generation DES-treated patients had the significantly lower MACE rates at 12months (P=0.03; OR: 0.69, 95% CI: 0.49,0.97). No differences in two groups were seen in all-cause death, MI, TVR, stent thrombosis and TLR.

CONCLUSIONS

Our limited evidence indicated that, second-generation DES in SVG patients, compared with first-generation DES, offered similar levels of safety, but were more effective than the former one.

Saphenous Vein Graft Interventions

Saphenous vein graft interventions compose a small but important subset of percutaneous coronary revascularization. Because of their unique biology, percutaneous angioplasty and stenting require tailored patient and lesion selection and modification of intervention technique to optimize outcomes. The use of embolic protection and appropriate adjunctive pharmacology can help minimize periprocedural complications, such as the no-reflow phenomenon. Recommendations for best practice in saphenous vein graft interventions continue to evolve with emerging research and therapy.

Paclitaxel-eluting nanofiber-covered self-expanding nonvascular stent for palliative chemotherapy of gastrointestinal cancer and its related stenosis

Self-expanding non-vascular metal stents (SEMS) is now a choice of treatment for tumor-induced obstructive symptoms of gastrointestinal tract. But in-growing tumor causes re-stenosis. Here, we studied a paclitaxel-eluting nanofiber-covered stent for palliative chemotherapy of gastrointestinal cancer and its related stenosis. In vivo and in vitro feasibility of nanofiber-covered nonvascular stent was evaluated in this study. Nanofiber-covered stent released paclitaxel (PTX) in controlled manner for 30 days. PTX-NFM significantly inhibited the growth of CT-26 colon cancer in comparison with PTX injection. PTX maintained higher tumor concentrations over 1.0 μg/ml for more than 14 days without systemic exposure. TUNEL and H&E staining proved locally concentrated PTX induced the higher apoptosis than PTX injection. In this way, PTX-eluting nanofiber-covered stent possibly inhibits in-growth of cancer and extends patency of stent. Clinical feasibility of PTX-eluting nanofiber nonvascular stent for cholangiocarcinoma and gastrointestinal cancers will be investigated in further studies.

An update on coronary bypass graft intervention

Coronary artery bypass grafting (CABG) remains one of the most common surgical procedures. In spite of great advancements like arterial grafts and off-pump bypass procedure, recurrent ischaemia may ensue with the lesions of the graft. Early postoperative ischaemia (<30 days) is due to graft occlusion or stenosis, and percutaneous coronary intervention (PCI) is frequently feasible. Late postoperative ischaemia (>3 years) is most often due to a saphenous vein graft (SVG) lesion. Multiple diseased grafts, reduced left ventricular function, and available arterial conduits favour repeat CABG, whereas, a patent left internal mammary artery to left anterior descending favours PCI. Embolic protection reduces atheroembolic myocardial infarction during PCI of SVG and should be routinely used in treatment of SVG lesions. A variety of vasodilators may reduce the risk of or mitigate the consequences of no-reflow. Drug-eluting stents reduce restenosis in SVG grafts, and have become the default strategy for many interventionalists.

Differential 1-year clinical outcomes for ST-segment elevation myocardial infarction related to stent thrombosis or saphenous vein graft thrombosis

AIM

Thrombosis of stents and of saphenous vein grafts (SVG) remains a severe complication of either revascularization techniques that often are present as ST elevation myocardial infarction (STEMI). The aim of this longitudinal cohort study was to compare the 1-year clinical outcomes among STEMI patients requiring primary PCI due to stent thrombosis and graft occlusion presenting with STEMI.

METHODS AND RESULTS

We prospectively collected data on all patients undergoing primary PCI at the Montreal Heart Institute between April 1, 2007 and March 30, 2008. Study patients were grouped according to the etiology of the STEMI: stent thrombosis, graft thrombosis, or atherosclerosis-related STEMIs (control group). The primary combined end-point, major adverse cardiac events (MACE), was defined as death, myocardial infarction, and target vessel revascularization within 12 months as primary end point. Of the 489 STEMI patients included in the study, 23 were due to stent thrombosis, 22 to graft thrombosis, and 444 in the control group. Stent and graft thromboses were associated with a higher MACE rates, 26.1 and 22.7%, respectively, compared to the control group, 9.3% (P = 0.004). Moreover, only stent thrombosis was associated with an increased risk of MACE (HR 2.57, confidence interval 95% 1.08-6.08.

CONCLUSION

Patients with stent thrombosis present with higher rate of reinfarction while graft thrombosis is associated with an increase in 1-year cardiac mortality. Using multivariate analysis, higher MACE rates were associated with stent thrombosis as compared to graft thrombosis.

Two-year follow-up of outcomes of second-generation everolimus-eluting stents versus first-generation drug-eluting stents for stenosis of saphenous vein grafts used as aortocoronary conduits

Second-generation everolimus-eluting stents (EESs) have demonstrated superiority in efficacy and safety compared with first-generation drug-eluting stents (DESs) in the treatment of native coronary artery lesions. The present study evaluated and compared the safety and efficacy of EESs and first-generation DESs in saphenous vein graft lesions. The EES group consisted of 88 patients with 96 lesions, and the first-generation DES group consisted of 243 patients with 317 lesions (sirolimus-eluting stents, n = 212; paclitaxel-eluting stents, n = 105). The end points included target lesion revascularization, target vessel revascularization, major adverse cardiovascular events (composite of all-cause death, myocardial infarction, and target vessel revascularization), and definite stent thrombosis at 2 years. The groups had similar baseline characteristics and graft ages (128.1 ± 77.5 vs 132.4 ± 90.8 months, p = 0.686). The EES group had more type C lesions and less embolic protection device use. The peak postprocedure values of creatinine kinase-MB and troponin I were similar between the 2 groups. Overall, major adverse cardiovascular events occurred in 18.2% of EES patients and 35.0% of first-generation DES patients (p = 0.003), mainly driven by a lower target vessel revascularization rate (6.8% vs 24.5%, p <0.001). The target lesion revascularization rate was lower in the EES group (1.1% vs 11.6%, p = 0.005). Stent thrombosis was low and similar between the 2 groups (0% vs 0.8%, p = 1.000). On multivariate analysis, the type of DES implanted and graft age were the only independent predictors of major adverse cardiovascular events. In conclusion, the superiority of EESs compared with first-generation DESs shown in native artery lesions has been extended to saphenous vein graft lesions and should be considered as the DES of choice for this lesion type.

Current percutaneous treatment strategies for saphenous vein graft disease

Coronary artery bypass graft surgery remains one of the most widely performed surgical procedures in North America and aortocoronary saphenous vein grafts (SVG) are the most frequently used surgical conduits. SVG disease (SVGD) remains the leading cause of symptomatic coronary artery disease postcoronary artery bypass graft. When optimal medical therapy is ineffective, repeat surgery is associated with higher mortality combined with less favorable clinical and angiographic results, thus percutaneous revascularization on SVG is currently the standard of care for the revascularization of SVGD. Balloon angioplasty, bare metal stents, polytetrafluoroethylene-covered stents, and drug-eluting stents have been extensively investigated for SVG interventions. Multiple recent randomized trials and meta-analyses have confirmed the pathophysiologic and clinical differences between SVGD and coronary artery disease. Decisions such as patient selection, premedication, stent, and protection device characteristics should be carefully considered to achieve optimal procedural and clinical results. Acute coronary syndromes due to SVG involvement, chronic total occlusions, retrograde approaches, and SVG perforation management are newer fields requesting additional research.

Saphenous vein graft failure after coronary artery bypass surgery: pathophysiology, management, and future directions

OBJECTIVE

To review our current understanding of the epidemiology and pathogenesis of vein graft failure (VGF), give an overview of current preventive and interventional measures, and explore strategies that may improve vein graft patency.

BACKGROUND

VGF and progression of native coronary artery disease limit the long-term efficacy of coronary artery bypass graft surgery.

METHODS

We reviewed the published literature on the pathophysiology, prevention, and/or treatment of VGF by searching the MEDLINE (January 1, 1966-January 1, 2012), EMBASE (January 1, 1980-January 1, 2012), and Cochrane (January 1, 1995-January 1, 2012) databases. In addition, we reviewed references from the selected articles for studies not identified in the initial search. Basic science and clinical studies were included; non-English language publications were excluded.

RESULTS

Acute thrombosis, neointimal hyperplasia, and accelerated atherosclerosis are the 3 mechanisms that lead to VGF. Preventive measures include matching and quality assessment of conduit and target vessel, lipid-lowering drugs, antithrombotic therapy, and cessation of smoking. Treatment of VGF includes medical therapy, percutaneous intervention, and redo coronary artery bypass graft surgery. In patients undergoing graft intervention, the use of drug-eluting stents, antiplatelet agents, and embolic protection devices may improve clinical outcomes.

CONCLUSIONS

Despite advances in management, VGF remains one of the leading causes of poor in-hospital and long-term outcomes after coronary artery bypass graft surgery. New developments in VGF prevention such as gene therapy, external graft support, fully tissue-engineered grafts, hybrid grafts, and synthetic conduits are promising but unproven. Future efforts to reduce VGF require a multidisciplinary approach with a primary focus on prevention.

Embolic Protection Devices for Saphenous Vein Graft Percutaneous Coronary Interventions

Saphenous vein graft (SVG) percutaneous coronary interventions (PCIs) are associated with adverse clinical events caused by distal embolization in 10% to 20% of cases. Various embolic protection devices (EPDs) have been developed to lower the risk of distal embolization during SVG PCI: distal balloon occlusive devices, distal embolic filters, and proximal balloon occlusive devices. Despite evidence for improved outcomes and cost-effectiveness, rates of national EPD use remain low, the main cause of underutilization being operator preference. With increasing familiarity of operators with EPDs, their use should continue to increase in SVG PCI and lead to better outcomes.

Drug-Eluting Stents Versus Bare Metal Stents in Saphenous Vein Graft Intervention

Percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) is associated with higher adverse event rates, lower procedural success, and inferior longterm patency rates compared with native vessel PCI. The ability to comply with dual antiplatelet therapy, and whether the patient will need an interruption in dual antiplatelet therapy, should be considered when deciding whether to implant a drug-eluting stent (DES) or bare metal stent (BMS) in an SVG. DES should be used for SVG PCI because they seem to reduce target vessel revascularization. This article reviews the evolution and contemporary evidence regarding use of DES versus BMS in SVG PCI.

Degenerated Saphenous Vein Graft Intervention: Should We Target the Native Vessel instead?

Coronary interventions of degenerated saphenous vein grafts (SVGs) continue to present a management challenge. Although repeat coronary artery bypass grafting (CABG) remains a significant risk factor for operative mortality, percutaneous coronary intervention (PCI) is still associated with a high risk for periprocedural events. There is a lack of consensus on the optimal treatment strategy for patients with severe stenosis of SVGs. It is imperative to review the characteristics of native versus SVG disease, risk factors for complications after SVG intervention, procedural treatment strategies important to the decision on which therapeutic strategy to follow, and measures to mitigate the risks of periprocedural complications.

Management of Complications During Saphenous Vein Graft Interventions

Because of greater patient comorbidities, more diffusely diseased vessels, and the greater possibility of mechanical complications, saphenous vein graft interventions are fraught with complications. The greatest risk is a higher risk of periprocedural myocardial infarction due to distal embolization of microemboli. The risk for noreflow in a patient with concomitant native critical vessel disease can have grave consequences. Minimizing the risk of periprocedural myocardial infarction with the use of distal embolic protection, understanding the role of adjunctive pharmacotherapy, and learning how to manage less common but serious mechanical complications during saphenous vein graft interventions are important to ensure optimal patient outcomes.

Optimal Stenting in Saphenous Vein Graft Intervention

Percutaneous interventions of (usually degenerated) saphenous vein grafts (SVG) are associated with higher risk of distal embolization and worse clinical outcomes, including target vessel revascularization, myocardial infarction, and death, as compared with percutaneous coronary intervention of native coronary arteries. Embolic protection devices have demonstrated value in reducing the risk of embolization and postprocedural enzyme elevation after SVG interventions. Frequently, however, such devices are not used or cannot be used. As a result, novel stenting strategies intended to decrease the risk of periprocedural myocardial infarction seem to play a major role in enhancing the results following SVG interventions.