Risk assessment of slow or no-reflow phenomenon in aortocoronary vein graft percutaneous intervention

Relationship between systemic immune-inflammation index and no-reflow in percutaneous coronary intervention for saphenous grafts

Objective: In this study, we investigated the occurrence of no-reflow (NR) in percutaneous coronary intervention (PCI) for saphenous vein grafts (SVGs) and its relationship with a new systemic immune-inflammation index (SII) that determines inflammation. Methods: We studied 303 patients with acute coronary syndrome without ST elevation who underwent PCI for SVG disease. Results: NR formation during SVG PCI was significantly higher in patients with high SII (p < 0.001). NR occurrence was 12.8% when SII was ≤548 and 41.9% when SII was >548. Conclusion: Our study is the first to investigate SII as the state of inflammation and its effect on the SVG PCI. Patients with higher SII have a higher risk of NR during an SVG for PCI.

Advances in the Post-coronary Artery Bypass Graft Management of Occlusive Coronary Artery Disease

Revascularisation of chronic total occlusion (CTO) represents one of the most challenging aspects of percutaneous coronary intervention, but advances in equipment and an understanding of CTO revascularisation techniques have resulted in considerable improvements in success rates. In patients with prior coronary artery bypass grafting (CABG) surgery, additional challenges are encountered. This article specifically explores these challenges, as well as antegrade methods of CTO crossing. Techniques, equipment that can be used and reference texts are highlighted with the aim of providing potential CTO operators adequate information to tackle additional complexities likely to be encountered in this cohort of patients. This review forms part of a wider series where additional aspects of patients with prior CABG should be factored into decisions and methods of revascularisation.

[Our enemy : the clot. Coronary thrombosis : strategy and therapeutic arsenal]

Intra coronary thrombus is  frequently encountered during acute coronary syndromes revascularisation procedures. It can also be encountered during angioplasty procedures in a stable angina context, although at a much lesser frequency.In both situations, it harbors a risk of poor angiographic result and poor prognosis. Intracoronnary thrombus may cause coronary occlusion at the angioplasty site or distal embolic  flow obstruction. Per procedure thrombus prevention rests on an prior optimal anti thrombotic treatment and in some circumstances the choice to defer the revascularisation procedure in the complex high risk setting. Treating the initiated thrombus remains controversial concerning thrombectomy and GPIIBIIIa inhibitors which are still in use in common practice. No reflow phenomenon is a particularly complex setting during cornary angioplasties, partially but not solely related to a thrombotic complication. It's treatment remains unclear in the absence of related oriented studies.The current mechanical and pharmacological antithrombotic therapies must remain common practice and used appropriately as of the clinical and angiographic setting, until further scientific outbrakes.

Association of CHA2DS2-VASc score with thrombus burden in patients with acute myocardial infarction undergoing SVG-PCI

BACKGROUND

The rate of saphenous vein graft (SVG) occlusion within the first year of bypass graft surgery is 15%. The CHA₂DS₂-VASc score is used to predict the risk of thromboembolic events in patients with nonvalvular atrial fibrillation. We aimed to evaluate the predictive role of the CHA₂DS₂-VASc score in the estimation of intracoronary thrombus burden in patients with acute myocardial infarction (AMI) who underwent SVG-PCI.

METHODS

We retrospectively evaluated 221 patients who were admitted with AMI and underwent PCI of SVGs at the Department of Cardiology in the Turkiye Yuksek Ihtisas Education and Research Hospital between 2012 and 2018. The study population was divided into two groups according to their Thrombolysis in Myocardial Infarction (TIMI) thrombus grade: low thrombus burden (LTB; TIMI 0-3) and high thrombus burden (HTB; TIMI 4 and 5).

RESULTS

The study included 221 patients with a mean age of 63.3 ± 6.7 years. The patients with HTB had significantly higher CHA₂DS₂-VASc scores (p < 0.001) compared with LTB patients. Univariate and multivariate regression analysis demonstrated that both CHA₂DS₂-VASc score (OR: 1.573, 95% CI: 1.153-2.147, p = 0.004) as a continuous variable and a binary cut-off level of the CHA₂DS₂-VASc score > 3 (OR: 3.876, 95% CI: 1.705-8.808, p = 0.001) were significantly associated with HTB. The ability of the CHA₂DS₂-VASc score to predict HTB burden was evaluated by receiver-operating characteristics analysis curve analysis. The optimum cut-off value of the CHA₂DS₂-VASc score for predicting HTB was 3 (with a sensitivity of 67.9% and a specificity of 69.3%) according to the Youden index.

CONCLUSION

The CHA₂DS₂-VASc score can be used as an easy practical tool to predict HTB in AMI patients undergoing SVG-PCI.

Plateletcrit may predict no-reflow after saphenous vein graft interventions in patients with non-ST elevation myocardial infarction

Saphenous vein graft (SVG) percutaneous coronary interventions (PCIs) are procedures with potential complications such as distal embolization, slow or no-reflow phenomenon. Platelets are the main factors in development of thrombus and no-reflow phenomenon. There have been multiple studies that identified the association between plateletcrit (PCT) and cardiovascular outcomes. The aim of the study was to investigate whether PCT can predict the development of no-reflow in patients with non-ST elevation myocardial infarction (NSTEMI) undergoing PCI for SVG disease. A total of 181 patients who underwent PCI for SVG disease with NSTEMI were included retrospectively. Platelet indices on admission were recorded. Patients were divided into two groups according to the development of no-reflow during the procedure: no-reflow (n = 32; 18%) and normal reflow (n = 149; 82%). PCT and platelet count were higher in the no-reflow group (0.254 vs. 0.224, P = 0.020; 265.4 vs. 233, P = 0.011, respectively). The PCT cut-off value for predicting no-reflow was calculated as 0.230 by ROC curve analysis with 68.8% sensitivity and 51.0% specificity. Multivariate logistic regression analysis showed that PCT was an independent predictor of no-reflow (odds ratio: 5.091, confidence interval: 1.356-19.116, P = 0.016). PCT may be useful in identifying patients at risk for developing no-reflow in patient with NSTEMI undergoing SVG PCI.

Complications and failure modes of coronary embolic protection devices: Insights from the MAUDE database

BACKGROUND

There is limited data on complications associated with the use of coronary embolic protection devices (EPDs).

METHODS

We queried the Manufacturer and User Facility Device Experience database between November 2010 and November 2020 for reports on coronary EPDs: Spider FX (Medtronic, Minneapolis, MN) and Filterwire EZ (Boston Scientific, Natick, MA).

RESULTS

We retrieved 119 reports on coronary EPD failure (Spider FX n = 33 and Filterwire EZ n = 86), most of which (78.2%) occurred during saphenous vein graft interventions. The most common failure mode was inability to retrieve the EPD (49.6%), with the filter trapped against stent struts in 76.2% of the cases. Other device complications included filter fracture (28.6%), failure to cross (7.6%), failure to deploy (7.6%), and failure to recapture the filter (3.4%). Filter fracture (54.5 vs. 29.1%) and failure to recapture (9.1 vs. 2.1%) were more commonly reported, while failure to deploy the filter (0 vs. 10.5%) was less commonly reported with the Spider-FX.

CONCLUSIONS

The most common modes of failure of coronary EPDs are the failure of retrieval (49.6%), followed by the filter fracture (28.6%). When using EPDs, careful attention to the technique is essential to avoid failures and subsequent complications.

Predictors of Microvascular Reperfusion After Myocardial Infarction

Purpose of Review

In acute ST-segment elevation myocardial infarction (STEMI), successful restoration of blood flow in the infarct-related coronary artery may not secure effective myocardial reperfusion. The mortality and morbidity associated with acute MI remain significant. Microvascular obstruction (MVO) represents failed microvascular reperfusion. MVO is under-recognized, independently associated with adverse cardiac prognosis and represents an unmet therapeutic need.

Recent Findings

Multiple factors including clinical presentation, patient characteristics, biochemical markers, and imaging parameters are associated with MVO after MI.

Summary

Impaired microvascular reperfusion is common following percutaneous coronary intervention (PCI). New knowledge about disease mechanisms underpins precision medicine with individualized risk assessment, investigation, and stratified therapy. To date, there are no evidence-based therapies to prevent or treat MVO post-MI. Identifying novel therapy for MVO is the next frontier.

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.

Long-Term Clinical Outcomes of Percutaneous Coronary Intervention in Saphenous Vein Grafts in a Low to Middle-Income Country

Background Revascularization of saphenous vein grafts (SVGs) is challenging and debated for the last few decades. The percutaneous revascularization of SVGs was reported to have poorer long-term outcomes than native coronary artery revascularization. Purpose We aim to study the peri-procedural complications and long-term outcomes of the percutaneous revascularization of SVGs in a low-middle-income country. Methods In this retrospective study, we included 110 patients who underwent percutaneous revascularization from January 2011 to March 2020 and followed them retrospectively for long-term outcomes and major adverse cardiovascular events. Results The mean age was 71 ±9, and 81% were male. The most common reason for the presentation was non-ST segment elevation myocardial infarction (NSTEMI) (46%). The mean follow-up period of the study was 48±27 months. The most common comorbidity was hypertension (86%). A drug-eluting stent (80%) was placed in most of the patients, followed by a bare-metal stent (BMS) (14%) and percutaneous balloon angioplasty (POBA) (6%). We did not find any significant difference in major adverse cardiac events (MACE) (P=0.48), target vessel revascularization (TVR) (p=0.69), and target lesion revascularization (TLR) (p=0.54) with drug-eluting stent (DES) as compared to either BMS or POBA. The mean period from coronary artery bypass grafting (CABG) to SVG percutaneous coronary intervention (PCI) was 15± 5.5 years. Multivariate Cox regression analysis showed that an acute coronary syndrome (ACS) event, stroke, and female sex were independently associated with MACE. Conclusion The long-term outcomes of SVG PCI are not affected by the types of stents. Female gender, ACS, and stroke are the independent predictors of MACE after SVG PCI, and statin therapy has a positive impact on the long-term outcomes of SVG PCI.

Orbital Atherectomy and Heavily Calcified Saphenous Vein Graft Intervention

Percutaneous coronary intervention in the diseased saphenous vein graft differs significantly from that in the diseased native coronary artery. After being exposed to arterial pressures over time, vein grafts have substantially different plaque characteristics, with more inflammatory cells, more diffuse disease, and less calcification. Severe calcification of saphenous vein grafts, although uncommon, poses a high risk of stent underexpansion. Orbital atherectomy for treatment of de novo calcified coronary lesions has been associated with better outcomes at 5-year follow-up. However, there are no published data on the use of orbital atherectomy to treat severely calcified saphenous vein graft lesions. We present the case of a 77-year-old woman with non-ST-segment-elevation myocardial infarction who underwent successful orbital atherectomy to prepare a severely calcified saphenous vein graft lesion for stent implantation.

Prediction of Major Adverse Cardiovascular Events and Slow/No-Reflow by Virtual Histology Imaging After Percutaneous Interventions on Saphenous Vein Grafts

Saphenous vein grafts disease (SVGD) is a common complication after coronary artery bypass graft (CABG) and usually treated by percutaneous coronary intervention (PCI). In this prospective cohort study, we performed virtual histology-intravascular ultrasound to investigate whether plaque composition and morphological characteristics were associated with post-PCI major adverse cardiac events (MACEs) and slow/no-reflow in patients with SVGD. Patients (n = 90) were studied (76.7% men, mean age 64.9 ± 8.2 years and mean duration of SVG 8.0 ± 3.6 years). There were 77.8% lesions with a plaque burden of at least 70%; 18 MACE incidences accumulated in 14 patients over 12 months post-PCI and slow/no-reflow was observed in 12 patients. On adjusted multivariate analysis, lesion length (hazard ratio [HR] = 1.05; 95% confidence interval [CI]: 1.01-1.08]); age of CABG (HR = 1.51 [95% CI: 1.11-2.05], and absolute necrotic core (NC) area (HR = 8.04 [95% CI: 1.86-34.73]) were independently associated with MACEs. Factors independently associated with slow/no-reflow post-PCI were preprocedure systolic blood pressure (odds ratio [OR] = 0.98; 95% CI: 0.96-0.99) and absolute NC area (OR = 2.47 (95% CI: 1.14-5.36). A cutoff value of absolute NC area at ≥1.1 mm² may serve as a significant risk predictor for no-reflow after SVG-PCI. Factors associated with MACEs and the slow/no-reflow phenomenon following PCI of the SVG can be used in risk assessment of SVG.

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.

Contemporary Use of Embolic Protection Devices During Saphenous Vein Graft Intervention

BACKGROUND

Guidelines recommend use of embolic protection devices during percutaneous coronary intervention of saphenous vein grafts, but the use of these devices in contemporary practice is unclear. We thus sought to evaluate the patient characteristics and clinical outcomes associated with embolic protection device use during contemporary saphenous vein graft percutaneous coronary intervention.

METHODS AND RESULTS

We identified patients undergoing isolated saphenous vein graft percutaneous coronary intervention in the Veterans Affairs Healthcare System from January 2008 to June 2017. Patient and procedural characteristics associated with embolic protection device use were assessed, as well as unmeasured site variation. A propensity-matched cohort was constructed to compare outcomes at 30 days, including unsuccessful intervention, periprocedural myocardial infarction, and death. We identified 7266 vein graft interventions, and embolic protection was used in 37.9% of cases, with a significant decline over time ( P=0.001) that was most pronounced from 2014 to 2017 ( P<0.001). There was significant institutional variation in the use of embolic protection, with a 15.50 (95% credible interval, 9.21-29.71)-fold difference in odds of device use by changing facilities independent of patient or procedural factors. Use of embolic protection was associated with reduced risk of unsuccessful intervention (odds ratio, 0.27; 95% credible interval, 0.17-0.42) and 30-day mortality (odds ratio, 0.56; 95% credible interval, 0.36-0.87).

CONCLUSIONS

Use of embolic protection is decreasing with time and occurs in less than half of vein graft interventions. There is significant site variation in the use of embolic protection independent of patient characteristics, suggesting opportunities for the development of uniform practices to improve outcomes among those undergoing saphenous vein graft percutaneous coronary intervention.

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.

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.

Sealing Intermediate Nonobstructive Coronary Saphenous Vein Graft Lesions With Drug-Eluting Stents as a New Approach to Reducing Cardiac Events

Background—

The objective of this study was to assess the efficacy of sealing intermediate nonobstructive coronary saphenous vein graft (SVG) lesions with drug-eluting stents (DES; paclitaxel- or everolimus-eluting stents) for reducing major adverse cardiac events (MACE).

Methods and Results—

This was a randomized controlled multicenter clinical trial that enrolled patients with a previous coronary artery bypass graft who had developed at least 1 intermediate nonobstructive SVG lesion (30%–60% diameter stenosis by visual estimation). Patients were randomized (1:1) to DES implantation (SVG-DES) or medical treatment (SVG-MT) of the target SVG lesion. The primary efficacy outcome was the first occurrence of MACE defined as the composite of cardiac death, myocardial infarction, or coronary revascularization related to the target SVG during the duration of follow-up (minimum of 2 years). Secondary efficacy outcomes included MACE related to the target SVG lesion and overall MACE. A total of 125 patients (mean age 70±9 years, 87% men) were included, with a mean time from coronary artery bypass graft of 12±5 years. Sixty and 65 patients were allocated to the SVG-DES and SVG-MT groups, respectively. There were no events related to the target SVG at 30 days. After a median follow-up of 3.4 (interquartile range: 2.8–3.9) years, the MACE rate related to the target SVG was not significantly different in the 2 groups (SVG-DES: 15.0%, SVG-MT: 20.0%; hazard ratio, 0.65; 95% confidence interval, 0.23–1.53; P =0.33). There were no significant differences between groups in MACE related to the target SVG lesion (SVG-DES: 10.0%, SVG-MT: 16.9%; hazard ratio, 0.53; 95% confidence interval, 0.20–1.43; P =0.21) or global MACE (SVG-DES: 36.7%, SVG-MT: 44.6%; hazard ratio, 0.73; 95% confidence interval, 0.42–1.27; P =0.26).

Conclusions—

Sealing intermediate nonobstructive SVG lesions with DES was safe but was not associated with a significant reduction of cardiac events at 3-year follow-up.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01223443.

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.

Impact of lesion location on intravascular ultrasound findings and short-term and five-year long-term clinical outcome after percutaneous coronary intervention for saphenous vein graft lesions

BACKGROUND

Little is known about intravascular ultrasound (IVUS) findings and acute post-percutaneous coronary intervention (PCI) outcome and long-term clinical outcome between aorto-ostial lesion and shaft lesion after PCI for saphenous vein graft (SVG) lesions.

METHODS

Aorto-ostial lesion was defined as those arising within 3mm of the origin of SVG and shaft lesion was defined as those arising in remaining portion of SVG. We evaluated pre- and post-PCI IVUS images of 311 SVG lesions and compared IVUS findings and acute post-PCI outcome and 5-year clinical outcome between aorto-ostial lesion (n=64) and shaft lesion (n=247).

RESULTS

The presence of positive remodeling (40% vs. 22%, p=0.026), hypoechoic plaque (47% vs. 36%, p=0.035), plaque rupture (23% vs. 8%, p=0.008), multiple plaque rupture (9% vs. 2%, p=0.038), and an intraluminal mass (54% vs. 25%, p<0.001) were significantly more common in shaft lesion than in aorto-ostial lesion. Post-PCI no-reflow (15% vs. 5%, p=0.033), post-PCI tissue prolapse (TP) (40% vs. 23%, p=0.014), and post-PCI creatine kinase-MB elevation more than 3 times normal (14% vs. 8%, p=0.047) were observed more frequently after PCI for shaft lesion than for aorto-ostial lesion. At 5-year clinical follow-up, the incidences of death (25% vs. 13%, p=0.036) and myocardial infarction (24% vs. 11%, p=0.028), but not the rate of target vessel revascularization (36% vs. 25%, p=0.096), were significantly higher in patients with shaft lesion compared with those with aorto-ostial lesion.

CONCLUSIONS

SVG shaft lesion has more unstable plaque morphology and this may contribute to the worse acute PCI outcomes and long-term outcomes.

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.

No-Reflow Phenomenon: Pathophysiology, Diagnosis, Prevention, and Treatment. A Review of the Current Literature and Future Perspectives

No-reflow is responsible for 40% of the primary percutaneous coronary intervention without complete myocardial reperfusion despite successful reopening of the infarct-related artery. This review describes the main pathophysiological mechanisms of no-reflow, its clinical manifestation, including the strong association with increased in-hospital mortality, malignant arrhythmias, and cardiac failure as well as the diagnostic methods. The latter ranges from simple angiographic thrombolysis in myocardial infarction grade score to more complex angiographic indexes, imaging techniques such as myocardial contrast echo or cardiac magnetic resonance, and surrogate clinical end points such as ST-segment resolution. This review also summarizes the strategies of prevention and treatment of no-reflow, considering the most recent studies results regarding medical therapy and devices.

Intravascular ultrasound analysis of plaque characteristics and postpercutaneous coronary intervention catheterization outcomes according to the remodeling pattern in narrowed saphenous vein grafts

We assessed the plaque characteristics and postpercutaneous coronary intervention (PCI) outcome according to the remodeling pattern (positive remodeling [PR], n = 113; and intermediate/negative remodeling [IR/NR], n = 198) in 311 saphenous vein graft lesions using intravascular ultrasound. The remodeling index was the ratio of the lesion site saphenous vein graft area to the mean of the proximal and distal references (PR/remodeling index >1.05, IR 0.95 to 1.05, and NR <0.95). Tissue prolapse was defined as tissue extrusion through the stent strut after PCI, and the tissue prolapse volume was calculated by subtracting the lumen volume from the stent volume. The presence of hypoechoic plaque (59% vs 36%, p = 0.001), plaque rupture (26% vs 16%, p = 0.042), multiple plaque rupture (12% vs 5%, p = 0.020), and an intraluminal mass (59% vs 41%, p = 0.002) were more common in the PR lesions than in the IR/NR lesions. The plaque cavity area was significantly greater in the PR lesions than in the IR/NR lesions (0.83 ± 1.43 mm(2) vs 0.42 ± 1.07 mm(2), p = 0.009). Post-PCI no-reflow (19% vs 9%, p = 0.019) and post-PCI tissue prolapse (53% vs 27%, p <0.001) were observed more frequently, and the tissue prolapse volume was significantly greater after PCI for PR lesions than for IR/NR lesions (0.86 ± 1.30 mm(3) vs 0.34 ± 0.74 mm(3), p <0.001). PR was the independent predictor of post-PCI no-reflow (odds ratio 2.58, 95% confidence interval 1.25 to 5.64, p = 0.040) and post-PCI tissue prolapse (odds ratio 2.45, 95% confidence interval 1.46 to 5.41, p = 0.045). In conclusion, saphenous vein graft lesions with PR have vulnerable plaque and are associated with no-reflow and tissue prolapse after PCI.

Intravascular ultrasound findings that are predictive of no reflow after percutaneous coronary intervention for saphenous vein graft disease

The aim of this study was to investigate the relation between intravascular ultrasound (IVUS) findings and the no-reflow phenomenon and long-term outcome after percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) lesions. No reflow was defined as Thrombolysis In Myocardial Infarction grade 0, 1, or 2 flow after PCI. Of 311 patients who underwent IVUS before and after stenting, no reflow was observed in 39 patients (13%). Degenerated SVG (62% vs 36%, p = 0.002), IVUS-detected intraluminal mass (82% vs 43%, p <0.001), culprit lesion multiple plaque ruptures (23% vs 6%, p <0.001), and tissue prolapse (51% vs 35%, p = 0.043) were observed more frequently in patients with no reflow. In multivariate logistic regression analysis, an intraluminal mass (odds ratio [OR] 4.84, 95% confidence interval [CI] 1.98 to 10.49, p = 0.001), culprit lesion multiple plaque ruptures (OR 3.46, 95% CI 1.46 to 8.41, p = 0.014), and degenerated SVGs (OR 3.17, 95% CI 1.17 to 6.56, p = 0.024) were the independent predictors of no reflow after PCI. At 5-year clinical follow-up, rates of death (14, 36%, vs 55, 20%, p = 0.036) and myocardial infarction (13, 33%, vs 52, 19%, p = 0.039) were significantly higher in the no-reflow group. However, rate of target vessel revascularization was not significantly different between the 2 groups (15, 38%, vs 90, 33%, p = 0.3). IVUS-detected intraluminal mass, multiple plaque ruptures, and degenerated SVGs were associated with no reflow in SVG lesions after PCI. In conclusion, no reflow was associated with poor long-term clinical outcomes after PCI for SVG lesions.

Saphenous vein graft intervention

Saphenous vein grafts are commonly used conduits for surgical revascularization of coronary arteries but are associated with poor long-term patency rates. Percutaneous revascularization of saphenous vein grafts is associated with worse clinical outcomes including higher rates of in-stent restenosis, target vessel revascularization, myocardial infarction, and death compared with percutaneous coronary intervention of native coronary arteries. Use of embolic protection devices is a Class I indication according to the American College of Cardiology/American Heart Association guidelines to decrease the risk of distal embolization, no-reflow, and periprocedural myocardial infarction. Nonetheless, these devices are underused in clinical practice. Various pharmacological agents are available that may also reduce the risk of or mitigate the consequences of no-reflow. Covered stents do not decrease the rates of periprocedural myocardial infarction and restenosis. Most available evidence supports treatment with drug-eluting stents in this high-risk lesion subset to reduce angiographic and clinical restenosis, although large, randomized trials comparing drug-eluting stents and bare-metal stents are needed.

Acute vasomotor paralysis and potential downstream effects of paclitaxel from stents implanted for saphenous vein aorto-coronary bypass stenosis

Implantation of bare metal stents (BMS) induces the release not only of particulate debris, but also of soluble vasoconstrictors which contribute to microvascular impairment. So this study aimed at addressing the potential attenuation of such vasoconstriction using paclitaxel eluting stents (PES). Using a distal protection/aspiration device, coronary arterial blood was retrieved before and during stent [n = 14 BMS, n = 14 PES, n = 3 sirolimus eluting stents (SES)] implantation in patients with saphenous vein aorto-coronary bypass stenosis and analyzed for plasma serotonin and thromboxane B(2) concentrations. The vasoconstriction of rat mesenteric arteries with intact (+E) and denuded (-E) endothelium in response to coronary arterial or aspirate plasma was quantified and normalized to that by potassium chloride (KCl(max) = 100%). Coronary arterial plasma before stent implantation induced a vasoconstriction of 30-43%, which was independent of endothelial integrity. Serotonin-release was 2.2 ± 0.5 μmol/l with BMS and 2.0 ± 0.4 μmol/l with PES, thromboxane B(2)-release was 26 ± 5 pg/ml with BMS and 22 ± 8 pg/ml with PES. BMS- and SES-aspirate plasma induced a vasoconstriction of 68 ± 18% (+E)/93 ± 14% (-E) and 81 ± 17% (+E)/124 ± 14% (-E), respectively. In contrast, PES-aspirate plasma induced only minor vasoconstriction of 8 ± 3% (+E)/12 ± 5% (-E). Addition of paclitaxel to BMS-aspirate plasma attenuated vasoconstriction. PES-aspirate induced microtubular condensation in immunofluorescence microscopy. Results indicate that aspirate from PES implantation attenuates vasoconstriction, possibly secondary to microtubular stabilization. Such acute downstream vascular paralysis could be beneficial in preventing a no-reflow phenomenon in patients undergoing stenting.

Vasoconstrictor Potential of Coronary Aspirate From Patients Undergoing Stenting of Saphenous Vein Aortocoronary Bypass Grafts and Its Pharmacological Attenuation

Rationale:

Stent implantation into atherosclerotic plaques releases, apart from particulate debris, soluble substances that contribute to impaired microvascular perfusion.

Objective:

To quantify the release of vasoconstrictors and to determine the efficacy of coronary dilators to attenuate their action.

Methods and Results:

Using a distal protection/aspiration device, coronary arterial blood was retrieved before and during stenting in 22 patients with severe saphenous vein aorto-coronary bypass stenoses. The release of catecholamines, endothelin, serotonin, thromboxane B 2 , and tumor necrosis factor (TNF)α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma was normalized to that by KCl. Responses to selective receptor blockade, adenosine, nitroprusside, and verapamil against the aspirate-induced constriction were determined. The coronary arterial plasma withdrawn before stenting induced 21±5% and the aspirate plasma after stenting induced 95±8% of maximum KCl-induced vasoconstriction. Serotonin, thromboxane B 2 , and TNFα release into aspirate plasma increased by 1.9±0.2 μmol/L, 25.6±3.1 pg/mL, and 19.7±6.1 pg/mL, respectively, during stenting. The aspirate-induced vasoconstriction was largely antagonized by selective serotonin receptor blockade, with little further antagonism by additional thromboxane receptor blockade. TNFα did not induce constriction per se but potentiated the constriction with serotonin and the thromboxane-analog U-46619 in arteries +E. The concentrations to induce half-maximal vasodilation were comparable for nitroprusside (+E, 3.3×10 −8 ; −E, 1.9×10 −8 mol/L) and verapamil (+E, 8.3×10 −8 ; −E, 7.8×10 −8 mol/L), and the vasoconstriction was eventually eliminated. The vasodilator response to adenosine was dependent on functional endothelium and weaker.

Conclusion:

Serotonin is the main coronary vasoconstrictor after stenting, and thromboxane and TNFα somewhat potentiate the serotonin response. Nitroprusside and verapamil are more potent than adenosine to attenuate the aspirate plasma-induced vasoconstriction, and they are not dependent on functional endothelium.

Comparison of Plaque Sealing With Paclitaxel-Eluting Stents Versus Medical Therapy for the Treatment of Moderate Nonsignificant Saphenous Vein Graft Lesions: The Moderate VE in Graft LE sion Stenting With the T axus Stent and I ntravascular Ultrasound (VELETI) Pilot Trial

Background— The presence of moderate saphenous vein graft (SVG) lesions is a major predictor of cardiac events late after coronary artery bypass grafting. We determined the effects of sealing moderate nonsignificant SVG lesions with paclitaxel-eluting stents (PES) on the prevention of SVG atherosclerosis progression.

Methods and Results— Patients with at least 1 moderate SVG lesion (30% to 60% diameter stenosis) were randomized either to stenting the moderate SVG lesion with a PES (n=30, PES group) or to medical treatment alone (n=27, medical treatment group). Patients had an angiographic and intravascular ultrasound evaluation of the SVG at baseline and at 12-month follow-up. The primary end points were (1) the ultrasound SVG minimal lumen area at follow-up and (2) the changes in ultrasound atheroma volume in an angiographically nondiseased SVG segment. Mean time from coronary artery bypass grafting was 12±6 years, and mean low-density lipoprotein cholesterol level was 73±31 mg/dL. A total of 70 moderate SVG lesions (39±7% diameter stenosis) were evaluated. Significant disease progression occurred in the medical treatment group at the level of the moderate SVG lesion (decrease in minimal lumen area from 6.3±3.0 to 5.6±3.1 mm 2 ; P <0.001), leading to a severe flow-limiting lesion or SVG occlusion in 22% of the patients compared with none in the PES group ( P =0.014). In the PES group, mean minimal lumen area increased ( P <0.001) from 6.1±2.2 to 8.6±2.9 mm 2 at follow-up ( P =0.001 compared with the medical treatment group at 12 months). There were no cases of restenosis or stent thrombosis. No significant atherosclerosis progression occurred at the nonstented SVG segments. At 12-month follow-up, the cumulative incidence of major adverse cardiac events related to the target SVG was 19% in the medical treatment group versus 3% in the PES group ( P =0.091).

Conclusions— Stenting moderate nonsignificant lesions in old SVGs with PES was associated with a lower rate of SVG disease progression and a trend toward a lower incidence of major adverse cardiac events at 1-year follow-up compared with medical treatment alone, despite very low low-density lipoprotein cholesterol values. This pilot study supports further investigation into the role of plaque sealing in SVGs.

Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT002289835.

Angiographic and clinical outcome following paclitaxel-eluting stent (taxus) implantation: a single center experience

Coronary stents dramatically improve acute outcomes of percutaneous coronary interventions but also induce abundant intraluminal neointimal growth. Drug-eluting stents reduce intimal hyperplasia, the main cause of in-stent restenosis. The safety and beneficial effects of paclitaxel-eluting stents (Taxus) in patients treated in daily practice remains to be defined. The aim of this study was to report the late outcomes of Taxus implantation in patients with coronary artery disease. The study population consisted of 151 patients (202 stents) who had undergone coronary Taxus stent implantation between March 2003 and May 2005. Patients were eligible for enrollment if there was symptomatic coronary artery disease or positive functional testing, and angiographic evidence of single or multivessel disease with a target lesion stenosis of 70% in a 2.0 mm vessel. The control coronary angiographies were performed after stent deployment at 12 +/- 2.8 months, and approximately 2 years of follow-up was completed. The polymer-based paclitaxel-eluting stent has been shown to be effective in reducing restenosis. Patients were followed-up for 16.7 +/- 7.4 months. All patients survived after stent implantation, but 2 (1.3%) patients experienced acute myocardial infarction after 3 and 9 months following angioplasty. Recurrent angina pectoris was observed in 3 patients. Angiographic evidence of restenosis was observed in these 5 patients. Three patients underwent angioplasty because of re- stenosis, and coronary artery bypass grafting was conducted in the other 2 patients. The results indicate that Taxus stents can be implanted with a very high success rate and have encouraging long-term angiographic and clinical results.

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.

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.

Angiographic and clinical outcome following sirolimus-eluting stent (Cypher) implantation. A single center experience

OBJECTIVES

To investigate the late outcomes of sirolimus-eluting stent implantation in patients with coronary artery disease.

BACKGROUND

Drug-eluting stents reduce intimal hyperplasia, which is the main cause of in-stent restenosis. Sirolimus-eluting stents significantly reduce clinical and angiographic restenosis and improve event-free survival.

METHODS

The study population consisted of 207 patients (273 stents) who had undergone coronary Cypher stent implantation. Patients were eligible for enrollment if there was symptomatic coronary artery disease or positive exercise testing, and angiographic evidence of single or multivessel disease with a target lesion stenosis of > or = 70% in a > or = 2.25 mm vessel. Follow-up coronary angiography was performed 18 months after stent deployment. Patients were followed-up for a mean of 24.7 +/- 7.4 months.

RESULTS

All patients survived after stent implantation, but 5 (2.4%) patients experienced acute ST elevation myocardial infarction and 4 (1.9%) patients developed non-Q wave myocardial infarction following angioplasty. Recurrent angina pectoris was observed in 16 (7.7%) patients (11 stable angina pectoris and 5 unstable angina pectoris). Angiographic evidence of restenosis was observed in these 20 (9.66%) patients. The 5 other patients had noncritical angiographic restenosis. Eleven (5.3%) patients underwent angioplasty because of restenosis, and coronary artery bypass grafting was conducted in the other 9 (4.3%) patients.

CONCLUSION

The results of the present study indicate that Cypher stents could be implanted with a very high success rate and have encouraging long-term angiographic and clinical results.

Percutaneous Saphenous Vein Graft Intervention—A Review

Re-do coronary artery bypass graft (CABG) surgery carries significant risk to the patient and existing patent internal thoracic artery grafts. Stenting stenotic saphenous vein grafts (SVGs) with drug-eluting stents (DES) using embolic protection devices (EPDs) is therefore probably the optimum treatment. However, this is fraught with challenges such as distal embolisation and restenosis which may result in peri-procedural myocardial infarction and target vessel failure, respectively. This review focuses on the nature of SVG disease, percutaneous intervention utilising embolic protection and future directions aimed at combating the disappointingly high procedural complication rate and long-term recurrence in this group.

Intravascular ultrasonic differences between aorto-ostial and shaft narrowing in saphenous veins used as aortocoronary bypass grafts

Previous studies have reported differences in interventional complication rates that depend on saphenous vein graft (SVG) lesion location. However, little is known about morphologic differences between lesions in different SVG locations. We evaluated preintervention intravascular ultrasound (IVUS) images of 75 de novo SVG lesions (aorto-ostial, n = 15; shaft, n = 60) in 63 patients. IVUS data were measured at the minimal lumen area and at 2 proximal and 2 distal references. Positive remodeling was defined as a lesion site SVG area that was larger than the average of the 2 distal references. Shaft lesions more often contained soft plaque (60.0% vs 26.7%, p = 0.02). Minimal lumen areas were identical (4.5 +/- 2.9 vs 4.3 +/- 1.5 mm2, p = 0.3); however, plaque burden at the minimal lumen area was greater in shaft locations (79.3 +/- 9.4% vs 72.1 +/- 9.2%, p = 0.01). The frequency of positive remodeling in shaft versus aorto-ostial lesions was 70.2% versus 26.7% (p = 0.002). SVG shaft lesions have more soft plaque and larger plaque burdens and undergo positive remodeling more frequently than SVG aorto-ostial lesions. These IVUS differences may account for some of the location-specific differences in interventional complications.

Percutaneous coronary intervention of or through saphenous vein grafts or internal mammary arteries: the impact of stents, adjunctive pharmacology, and multicomponent distal protection

We hypothesized that the use of stents and aggressive adjunctive pharmacotherapies has been associated with lower rates of complicating myocardial infarction (MI) and improved long-term outcomes compared to either previous balloon-only percutaneous coronary intervention (PCI) or atheroablative intervention for lesions of or through saphenous vein grafts (SVGs) and/or internal mammary arteries (IMAs). PCI of SVG has been complicated by relatively high rates of procedural MI and less favorable long-term outcomes than native vessel PCI, stimulating the development and application of an array of technologies. This study was based on retrospective review of stent-era (1999-2004) 5-year experience of a single center with 95 SVG procedures in 85 patients and 20 IMA procedures in 20 patients. These cases were compared with the previously published experience of one of the operators during the balloon-only period and literature review of the application of multiple technologies to SVG intervention, as well as consideration of the reoperation alternative. There was one in-hospital death each in the SVG cohort (1%) and in the IMA cohort (5%). There were SIX procedural MIs (6%), defined by total CK > normal, and 19 procedural MIs (20%) based on troponin-I > 1.0. Follow-up has been from 4 months to 5 years (average, 2.5 years), with 91% survival and one late CABG in the IMA group. SVG PCI with stents and adjunctive pharmacotherapies is associated with relatively low rates of procedural MI and favorable long-term outcomes.

Immediate and one-year outcome of percutaneous intervention of saphenous vein graft disease with paclitaxel-eluting stents

The aim of this study was to evaluate the outcome after paclitaxel-eluting stent implantation in 40 patients with 52 saphenous vein graft lesions. By Kaplan-Meier estimates, the probability of major adverse cardiac event-free survival for 1 year was 92.5%. A paclitaxel-eluting stent for saphenous vein graft disease appears to be feasible and safe, with a low rate of reintervention at 1 year, but late follow-up is needed to confirm these observations.

GuardWire emboli protection device is associated with improved myocardial perfusion grade in saphenous vein graft intervention

BACKGROUND

Use of emboli protection devices (EPD) during saphenous vein graft percutaneous coronary intervention (SVG-PCI) has been proven to reduce major adverse cardiac events (MACE). However, the impact of EPD on the microcirculation using Thrombolysis in Myocardial Infarction myocardial perfusion grade (TMP) has not been fully characterized. We sought to analyze TMP after SVG-PCI with and without EPD and determine its impact on inhospital MACE.

METHODS

From August 2001 to December 2002, 305 patients had SVG-PCI suitable for EPD; 210 (69%) had an angiogram appropriate for TMP evaluation. Of those, 46 (22%) had an EPD (GuardWire, Medtronic, Minneapolis, Minn) deployed during the coronary intervention. Both groups were similar with regard to most demographic and clinical features.

RESULTS

A TMP score of 2.5 or 3 was obtained in 98% of the EPD group versus 85% of the unprotected SVG-PCI (P = .01). There was a trend towards reduction in MACE when using EPD (15% vs 27%, respectively, P = .07). Peak postprocedural creatine kinase-MB was somewhat lower in the EPD group (6.03 +/- 7.8 ng/mL vs 14.87 +/- 42 ng/mL, P = .17) Patients with a TMP grade of 2.5 or 3 had a statistically significant reduction in MACE (OR 0.36, 95% CI 0.14-0.87, P = .02).

CONCLUSIONS

Compared with SVG-PCI without emboli protection, EPD significantly improved TMP and trended towards a reduction in MACE.

Procedural results and distal embolization after saphenous vein graft stenting and angioplasty for in-stent restenosis of grafts

Saphenous vein graft (SVG) angioplasty is associated with frequent periprocedural complications due to distal embolization and a high risk of restenosis. The purpose of this single-center, retrospective study was to determine the distal embolization incidences and outcomes of stenting for SVG lesions and percutaneous angioplasty for in-stent restenosis of these SVGs. We studied 48 consecutive patients (mean age, 62 +/- 7 years, 92% men) who had prior CABG and underwent stent deployment to SVG lesions detected at our institution over a period of 4 years. Mean lesion length was 12.4 +/- 3.2 mm. The minimal lumen diameter increased from 0.7 +/- 0.3 mm to 3.2 +/- 0.4 mm after stenting. Distal embolization as no reflow/slow flow phenomenon occurred in 5 (10%) patients. Angiographic success was achieved in 98% of the patients. Procedural success was achieved in 96% of the patients. No reflow/slow flow phenomenon was observed, particularly in patients with acute coronary syndrome. During the follow-up, 11 patients (23%) had angiographic evidence of restenosis. Lesions were treated with balloon angioplasty and the minimal lumen diameter increased from 2.6 +/- 1.1 mm to 3.1 +/- 0.3 mm. The angiographic and procedural success rates were both 100%. There were no cases of "no" reflow/slow flow. Restenosis was particularly frequent in patients with diabetes mellitus, hypercholesterolemia, and acute coronary syndrome. Stent implantation in patients with de novo SVG lesions can be achieved with a high rate of angiographic and procedural success. The distal embolization risk is lower during angioplasty of in-stent restenosis lesions of SVGs compared to de novo SVG lesions.