Prevention of distal embolization during coronary angioplasty in saphenous vein grafts and native vessels using porous filter protection

A fresh look at coronary microembolization

Mechanical stress from haemodynamic perturbations or interventional manipulation of epicardial coronary atherosclerotic plaques with inflammatory destabilization can release particulate debris, thrombotic material and soluble substances into the coronary circulation. The physical material obstructs the coronary microcirculation, whereas the soluble substances induce endothelial dysfunction and facilitate vasoconstriction. Coronary microvascular obstruction and dysfunction result in patchy microinfarcts accompanied by an inflammatory reaction, both of which contribute to progressive myocardial contractile dysfunction. In clinical studies, the benefit of protection devices to retrieve atherothrombotic debris during percutaneous coronary interventions has been modest, and the treatment of microembolization has mostly relied on antiplatelet and vasodilator agents. The past 25 years have witnessed a relative proportional increase in non-ST-segment elevation myocardial infarction in the presentation of acute coronary syndromes. An associated increase in the incidence of plaque erosion rather than rupture has also been recognized as a key mechanism in the past decade. We propose that coronary microembolization is a decisive link between plaque erosion at the culprit lesion and the manifestation of non-ST-segment elevation myocardial infarction. In this Review, we characterize the features and mechanisms of coronary microembolization and discuss the clinical trials of drugs and devices for prevention and treatment.

LDL-C and Total Stent Length are Independent Predictors of Periprocedural Myocardial Injury and Infarction for Unstable Angina Patients Undergoing Elective Percutaneous Coronary Intervention

Background

To investigate the predictive value of low-density lipoprotein cholesterol (LDL-C), total stent length and number of implanted stents in patients with unstable angina (UA) regarding myocardial injury and infarction during perioperative period.

Methods

Three hundred and fifteen consecutive UA patients between January 2015 and June 2018 were retrospectively recruited from two cardiac centers of Hebei Province, China. These patients had normal preprocedural cardiac troponin I (cTnI) and underwent uneventful revascularizations. The predictive value of baseline LDL-C level and total stent length was investigated by linking to post procedural cTnI value in this cohort. Meanwhile, other related clinical and procedural variables were analyzed.

Results

Baseline LDL-C level or LDL-C grade was correlated with post percutaneous coronary intervention (PCI) cTnI levels (r = 0.120, P = 0.01; r = 0.157, P = 0.004). LDL-C grade was an independent risk factor of perioperative myocardial injury and infarction (P < 0.05) after multivariable adjustment. The risk increased with the elevation of baseline LDL-C level. Compared to the lowest level group (<70 mg/dl), the group with 70–99 mg/dl carried three times higher risk (OR = 3.318; 95% CI: 1.167–9.436; P < 0.05). And, patients with LDL-C level ≥100 mg/dl had the worst prognosis (OR = 4.783; 95% CI: 1.736–13.180; P = 0.002). Besides, the study also found that the total length of stent was predictive of perioperative myocardial injury and infarction independently (OR = 1.037; 95% CI: 1.017–1.058; P = 0.001).

Conclusion

Baseline LDL-C level and total stent length were independent predictors of periprocedural myocardial injury and infarction in UA patients undergoing elective PCI.

Residual stenosis after carotid artery stenting: Effect on periprocedural and long-term outcomes

Objective

This study investigated the effect of residual stenosis after carotid artery stenting (CAS) on periprocedural and long-term outcomes.

Methods

Patients treated with CAS for symptomatic or asymptomatic carotid arterial stenosis were consecutively enrolled. Residual stenosis was estimated from post-procedure angiography findings. The effects of residual stenosis on 30-day periprocedural outcome and times to restenosis and clinical outcome were analyzed using logistic regression models and Wei-Lin-Weissfeld models, respectively.

Results

A total of 412 patients (age, 64.7 ± 17.0 years; male, 82.0%) were enrolled. The median baseline stenosis was 80% (interquartile range [IQR], 70–90%), which improved to 10% (0–30%) for residual stenosis. Residual stenosis was significantly associated with periprocedural outcome (adjusted odds ratio, 0.983; 95% confidence interval [CI], 0.965–0.999, P = 0.01) after adjustment for baseline stenosis, age, hypertension, symptomaticity, and statin use. Over the 5-year observation period, residual stenosis did not increase the global hazard for restenosis and clinical outcome (adjusted hazard ratio, 1.011; 95% CI, 0.997–1.025. In the event-specific model, residual stenosis increased the hazard for restenosis (adjusted hazard ratio, 1.041; 1.012–1.072) but not for clinical outcome (adjusted hazard ratio, 1.011; 0.997–1.025).

Conclusions

Residual stenosis after carotid artery stenting may be useful to predict periprocedural outcome and restenosis.

Periprocedural Myocardial Infarction in Contemporary Practice

"Periprocedural myocardial infarction (MI) occurs infrequently in the current era of percutaneous coronary interventions (PCI) and is associated with an increased risk of mortality and morbidity. Periprocedural MI can occur due to acute side branch occlusion, distal embolization, slow flow or no reflow phenomenon, abrupt vessel closure, and nonidentifiable mechanical processes. Therapeutic strategies to reduce the risk of periprocedural MI include dual antiplatelet therapy, intravenous cangrelor in the periprocedural setting, intravenous glycoprotein IIb/IIIa inhibitor in high-risk patients, anticoagulation with unfractionated heparin, low-molecular-weight heparin or bivalirudin, and embolic protection devices during saphenous vein graft interventions."

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.

Microvascular Alterations After Temporary Coronary Artery Occlusion: The No-Reflow Phenomenon

In experimental models of temporary coronary artery occlusion, tissue perfusion at the microvascular level remains incomplete even after patency of the infarct-related epicardial coronary artery is established, and distinct perfusion defects develop within the risk zone. This no-reflow phenomenon can be regarded as a basic cardiac response to ischemia-reperfusion. Perfusion defects observed in the clinical realm after reperfusion therapy for myocardial infarction may substantially be related to this mechanism in addition to microembolization and activation of platelets, as suggested in several recent studies. A major determinant of the amount of no-reflow seems to be infarct size itself. Reperfusion-related expansion of noreflow zones occurs within the first hours after the reopening of the coronary artery with a parallel reduction of regional myocardial flow, resulting in a potential therapeutic window. With various cardioprotective interventions, a close correlation between the size of the anatomic no-reflow and necrosis is a reproducible feature, which suggests a causal link between both entities of ischemic cardiac damage. Although vasodilating interventions failed to uncouple no-reflow zones from necrosis, the steps in the causal chain between microvascular and myocardial damage remain to be identified. On a long-term basis, tissue perfusion after ischemia-reperfusion remains markedly compromised for at least 4 weeks. Recent morphometric cardiac analyses suggested that the level of tissue perfusion after 4 weeks is a significant predictor of various indices of infarct healing, such as scar thickness, and infarct expansion index. As a consequence, improving tissue perfusion might concomitantly improve the healing process, which may provide the pathoanatomic basis for prognostic implications of no-reflow.

Spontaneous and procedural plaque embolisation in native coronary arteries: pathophysiology, diagnosis, and prevention

The detachment of atherothrombotic material from the atherosclerotic coronary plaque and downstream embolisation is an underrecognized phenomenon and it causes different degrees of impairment of the coronary microcirculation. During treatment of obstructive atherosclerotic plaque by percutaneous coronary intervention (PCI) distal embolisation (DE) is considered to be inevitable and it is associated with potential clinical and prognostic implications. This review aims to assess the main aspects of both spontaneous and procedural DE, analyze their different pathophysiology, provide specific insights on the main diagnostic tools for their identification, and finally focus on the main strategies for their treatment and prevention.

Aspirate from human stented native coronary arteries vs. saphenous vein grafts: more endothelin but less particulate debris

Stent implantation into atherosclerotic coronary arteries releases particulate debris and soluble substances that contribute to impaired microvascular perfusion. Here we addressed the potential for microvascular obstruction in patients with stenotic native right coronary arteries (nRCA) compared with saphenous vein grafts on right coronary arteries (SVG-RCA). We enrolled symptomatic, male patients with stable angina pectoris and a flow-limiting stenosis in their nRCA or SVG-RCA ( n = 18/18). Plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Coronary aspirate was retrieved during stent implantation under protection with a distal occlusion/aspiration device and divided into particulate debris and plasma. The release of catecholamines, endothelin, serotonin, thromboxane B2, and tumor necrosis factor-α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma (without and with selective endothelin receptor blockade) was normalized to that by potassium chloride (KClmax = 100%). Plaque volume and composition were not different between nRCA and SVG-RCA. There was less particulate debris (65 ± 8 vs. 146 ± 23 mg; P < 0.05) and more endothelin release (5.8 ± 0.8 vs. 1.3 ± 0.7 pg/ml; P < 0.05) in nRCA than in SVG-RCA, whereas the release of the other mediators was not different. Aspirate from nRCA induced stronger vasoconstriction than that from SVG-RCA [nRCA, 78 ± 6% (+E)/84 ± 5% (−E); SVG-RCA, 59 ± 6% (+E)/68 ± 3% (−E); P < 0.05 nRCA vs. SVG-RCA], which was attenuated by a nonspecific endothelin and a specific endothelin receptor A antagonist. Thus coronary aspirate from stented nRCA is characterized by less debris but more endothelin and stronger vasoconstrictor response than that from SVG-RCA.

Treating thrombus in the coronary arteries

Primary percutaneous coronary intervention (PCI) has greatly improved outcomes in patients with ST-elevation myocardial infarction (STEMI) and has, therefore, become the preferred reperfusion strategy for this patient group. The goal of primary PCI is to achieve a thrombolysis in myocardial infarction (TIMI) 3 flow and also to restore adequate perfusion at the myocardial level. Distal thrombus embolization during primary PCI occurs frequently and is also associated with compromised long-term outcomes. In this article, we provide an overview of the treatment of thrombus and the role of thrombectomy in PCI for STEMI.

The comparison in reduction of QT dispersion after primary percutaneous coronary intervention according to existence of thrombectomy in ST-segment elevation myocardial infarction

BACKGROUND

Primary percutaneous coronary intervention (PPCI) is the standard treatment in patients with ST-segment elevation myocardial infarction (STEMI). Thrombectomy devices are used to remove thrombus or to prevent embolization of thrombus and plaque during PPCI. QT dispersion (the difference between maximal and minimal QT interval calculated on a standard 12-lead electrocardiogram) represents the regional nonuniformity of ventricular repolarization. It may reflect early coronary reperfusion in reducing electrophysiological instability by decreasing QT dispersion in the recovery phase after acute STEMI.

HYPOTHESIS

Our aim was to show whether an additional effect of thrombectomy on reducing QT dispersion will be seen in patients undergoing PPCI for STEMI.

METHODS

The study population included 80 consecutive patients who were admitted to the hospital within 12 hours after the onset of acute STEMI and angiographic evidence of intraluminal thrombus in the infarct-related artery. Patients with atrial fibrillation or flutter, intraventricular conduction abnormalities, pre-excitation, cardiogenic shock, cardiomyopathy, ventricular hypertrophy, and severe valvular heart disease were excluded from the study.

RESULTS

There were no significant differences between groups regarding gender, age, cardiovascular risk factors, and time from symptom onset to treatment, except for smoking, which was much higher in the PPCI plus thrombectomy group. Infarct-related artery distribution (left anterior descending artery [LAD] to non-LAD), and neither the rate of balloon predilatation nor stent implantation were different between groups. Successful coronary patency was achieved in each case. QT interval measurements were similar between groups at admission. However, at 24 hours, QT and QTc dispersions were less in the PPCI plus thrombectomy group (41 ± 9 vs 33 ± 7 ms, P < 0.05 and 45 ± 8 vs 35 ± 7 ms, P = 0.03, respectively), but not in the other QT interval measurements. When patients were divided into 2 groups according to infarct-related artery (LAD and non-LAD groups), QT interval measurement parameters did not show any significant differences.

CONCLUSIONS

Thrombectomy additional to PPCI helps more effective reperfusion at the microvascular level and provides additional prognostic information.

Bimodal response to aspirin loading in acute ST-elevation myocardial infarction

Patients with stable coronary disease who exhibit platelet hypo-responsiveness to aspirin (ASA) have worse outcomes. Little data exist regarding platelet response to ASA in ST-elevation myocardial infarction (STEMI) patients. Our objective was to assess acute platelet response to ASA loading in STEMI patients undergoing primary percutaneous coronary intervention (PCI). The study comprised 102 consecutive patients with STEMI. All patients received a loading dose of 300 mg chewable ASA upon admission. Platelet reactivity was assessed immediately prior to primary PCI, at a median of 95(63 139) minutes after ASA loading. A bimodal response to arachidonic acid (AA) stimulation was observed, such that two distinct populations could be discerned: "good responders" had a mean AA-induced platelet aggregation of 36 ± 11% vs. 79 ± 9% for "poor responders." Despite equivalent demographic, clinical, and angiographic characteristics, good responders were significantly more likely to demonstrate early ST-segment resolution ≥70% after primary PCI (80% vs. 48%, p = 0.001), suggestive of better myocardial reperfusion. Early inhibition of AA-induced platelet aggregation post-ASA loading in the setting of STEMI is associated with better tissue reperfusion; however, a sizeable proportion of patients do not achieve significant inhibition of AA-induced platelet aggregation in response to ASA loading at the time of primary PCI.

Coronary microvascular dysfunction in the clinical setting: from mystery to reality

Far more extensive than the epicardial coronary vasculature that can be visualized angiographically is the coronary microcirculation, which foregoes routine imaging. Probably due to the lack of techniques able to provide tangible evidence of its crucial role, the clinical importance of coronary microvascular dysfunction is not fully appreciated. However, evidence gathered over the last several decades indicates that both functional and structural abnormalities of the coronary microvasculature can lead to myocardial ischaemia, often comparable with that caused by obstructive coronary artery disease. Indeed, a marked increase in coronary microvascular resistance can impair coronary blood flow and trigger angina pectoris, ischaemic ECG shifts, and myocardial perfusion defects, and lead to left ventricular dysfunction in patients who otherwise have patent epicardial coronary arteries. This condition--often referred to as 'chest pain with normal coronary arteries' or 'cardiac syndrome X'--encompasses several pathogenic mechanisms involving the coronary microcirculation. Of importance, coronary microvascular dysfunction can occur in conjunction with several other cardiac disease processes. In this article, we review the pathogenic mechanisms leading to coronary microvascular dysfunction and its diagnostic assessment, as well as the different clinical presentations and prognostic implications of microvascular angina. As such, this review aims to remove at least some of the mystery surrounding the notion of coronary microvascular dysfunction and to show why it represents a true clinical entity.

National trends in carotid artery revascularization surgery

Object

Several randomized trials have emerged with conflicting data on the overall safety of carotid artery stenting (CAS) in comparison with carotid endarterectomy (CEA). The authors hypothesize that changes in national trends correspond to publication of randomized trials, including an increase in utilization of CAS after publication of trials favorable to CAS (for example, Carotid and Vertebral Artery Transluminal Angioplasty Study [CAVATAS] and Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy [SAPPHIRE]) and decrease in utilization of CAS after publication of trials favorable to CEA (for example, Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis [EVA3-S] and Stent-Supported Percutaneous Angioplasty of the Carotid Artery versus Endarterectomy [SPACE]).

Methods

The Nationwide Inpatient Sample was obtained for the years 1998–2008. Individual cases were isolated for principal diagnosis of unilateral or bilateral carotid artery stenosis or occlusion undergoing CEA or CAS. The percentage of CAS for all carotid revascularization procedures was calculated for each year. Perioperative inpatient morbidity, including stroke or death, were calculated and compared.

Results

The percentage of patients undergoing CAS increased yearly from the start of the observed period to the end, with the exception of a decrease in 2007. The peak utilization of CAS for carotid artery revascularization procedures was 15% of all cases in 2006. The stroke or death rate was consistent at 5% among all patients undergoing CEA for all years, while the incidence of stroke or death decreased among patients undergoing CAS from 9% in 1998 to 5% in 2008.

Conclusions

The practice of CAS in the US is expanding, from less than 3% of all carotid artery revascularization procedures to 13% in 2008. The utilization of CAS was seen to correlate with publication of randomized trials. Utilization nearly doubled in 2005 after publication of the CAS-favorable SAPPHIRE in 2004, and decreased by 22% after publication of the CEA-favorable EVA-3S and SPACE in 2007. With the publication of Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST), the authors predict a resultant increase in the rate of CAS for carotid artery disease in the upcoming years.

Lessons from human coronary aspirate

The interventional implantation of a stent into an atherosclerotic coronary artery is a unique and paradigmatic scenario of plaque rupture in humans. The use of protection devices not only prevents the released plaque particles and the superimposed thrombotic material from being washed and embolized into the coronary microcirculation of the individual patient, but permits also the retrieval and ex vivo analysis of particulate plaque debris and soluble substances. The particulate debris comprises typical cholesterol crystals, foam cells, hyalin material and calcium deposits from the atheroma as well as platelets and coagulation material; soluble substances include vasoconstrictors, such as serotonin and thromboxane, as well as inflammatory mediators, such as TNFα which amplifies vasoconstriction by inducing endothelial dysfunction. The vasoconstriction observed in a bioassay ex vivo correlates to clinical symptoms, angiographic stenosis and plaque burden, as assessed by intravascular ultrasound. The release of TNFα into the aspirate correlates to restenosis. Detailed analysis of the human coronary aspirate may promote a better understanding of the pathophysiology of the vulnerable atherosclerotic plaque and help to better antagonize the microvascular consequences of coronary microembolization, including the no reflow phenomenon. This article is part of a Special Issue entitled "Coronary Blood Flow."

Coronary microembolization causes long-term detrimental effects on regional left ventricular function

OBJECTIVES

To investigate whether coronary microemboli have long-term effects on left ventricular (LV) function in an experimental model. Furthermore, to determine if first-pass perfusion and late gadolinium enhancement (LGE) patterns differs between small- and large-sized microemboli.

DESIGN

Six pigs underwent left anterior descending (LAD)-coronary microembolization with small-sized (40-120 μm, n ∼ 250 000) microemboli using a combined x-ray and MRI-system. MR-images before, one hour after and 7-8 weeks after microembolization were obtained. Results were compared to MRI obtained by large-sized (100-300 μm, n ∼ 7200) microemboli.

RESULTS

Cine MRI showed an acute drop in ejection fraction (from 49.5 ± 2.6% to 32.5 ± 2.8) that substantially recovered at 7-8 weeks (47.5 ± 3.2%). Regional LV-function assessed as circumferential, longitudinal and radial strain declined in both microinfarcts and remote regions followed by partial recovery at 7-8 weeks. The decline in LV function and the severe perfusion deficit from the small microemboli was similar to the large microemboli at one hour. There was a significant recovery in perfusion at 7-8 weeks in the microinfarcts. LGE demonstrated the microinfarcts at 7-8 weeks but not at one hour and the microinfarcts were confirmed by histopathology.

CONCLUSION

Microembolization causes long-term, regional LV dysfunction and this study confirmed the need of a comprehensive MRI-protocol for the detection of microinfarcts. These findings suggest that even small microemboli (40-120 μm in diameter), which may escape the distal protective devices influence cardiac function.

Serum N-terminal pro-B-type natriuretic peptide levels at the time of hospital admission predict of microvascular obstructions after primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction

BACKGROUND

Significant microvascular obstruction (MVO) during primary percutaneous coronary intervention (PCI) may suggest severe myocardial damage. The predictive value of N-terminal pro-B-type natriuretic peptide levels (NT-proBNP) for MVO has not been previously evaluated.

HYPOTHESIS

The purpose of the study was to determine whether NT-proBNP levels measured upon hospital admission of ST-segment elevation myocardial infarction (STEMI) patients receiving primary PCI have predictive value for MVO.

METHODS

NT-proBNP levels were obtained upon admission to the emergency department, for 41 acute STEMI patients. Cardiac contrast-enhanced magnetic resonance imaging (CE-MRI) was performed within 4 days after PCI. The optimal cut-off value to predict grade 3 MVO was determined using a receiver operating characteristic (ROC) curve. Multivariate regression analysis was performed to determine predictors for grade 3 MVO.

RESULTS

MVO grade correlated with left ventricular ejection fraction (LVEF; r =-0.383, P = 0.013), peak serum creatine kinase MB iso-enzyme (CK-MB; r = 0.470, P = 0.002), and NT-proBNP levels (r = 0.357, P = 0.022). The optimal cut-off value to predict grade 3 MVO was an NT-proBNP level of ≥80 pg/mL. Multivariate regression analysis, including LVEF, peak CK-MB, and an NT-proBNP ≥80 pg/mL revealed that only an NT-proBNP ≥80 pg/mL was an independent factor related to grade 3 MVO.

CONCLUSION

NT-proBNP levels upon hospital admission have a predictive value for MVOs. Further study is needed to determine if protective treatment strategies are warranted in STEMI patients with high NT-proBNP levels at presentation.

Peri-procedural myocardial injury during percutaneous coronary intervention: an important target for cardioprotection

Percutaneous coronary intervention (PCI) has become the predominant procedure for coronary revascularization in patients with both stable and unstable coronary artery disease (CAD). Over the past two decades, technical advances in PCI have resulted in a better and safer therapeutic procedure with minimal procedural complications. However, about 30% of patients undergoing elective PCI sustain myocardial injury arising from the procedure itself, the extent of which is significant enough to carry prognostic importance. The peri-procedural injury which accompanies PCI might therefore reduce some of the beneficial effects of coronary revascularization. The availability of more sensitive serum biomarkers of myocardial injury such as creatine phosphokinase MB isoenzyme (CK-MB), Troponin T, and Troponin I has enabled the quantification of previously undetectable myocardial injury. Peri-procedural myocardial injury (PMI) can also be visualized by cardiac magnetic resonance imaging, a technique which allows the detection and quantification of myocardial necrosis following PCI. The identification of CAD patients at greatest risk of sustaining PMI during PCI would allow targeted treatment with novel therapies capable of limiting the extent of PMI or reducing the number of patients experiencing PMI.

Manual aspiration prior to stenting does not reduce the incidence of filter no reflow in saphenous vein graft lesions protected by FilterWire EX/EZ

BACKGROUND

The beneficial role of manual thrombus aspiration in thrombus-containing lesions has been proven in acute myocardial infarction but data is lacking in saphenous vein graft lesions.

METHODS

From January 2004 to December 2008, 74 consecutive post-bypass patients underwent percutaneous coronary interventions to 76 saphenous vein graft lesions under the protection of FilterWire EX/EZ. Among them, the latest 25 consecutive patients with 25 lesions were treated with manual aspiration before stenting. The incidence of filter no reflow was compared between patients with and without manual aspiration pretreatment.

RESULTS

No major difference in demography, clinical, lesion, and procedure characteristics, and in-hospital outcome has been observed between the two patient groups. Most importantly, the incidence of filter no reflow has not been reduced (32.0% versus 19.6%, P = 0.26) by manual aspiration, even among thrombus-containing lesions (63.2% versus 64.7%, P = 1.00). The absence of diabetes mellitus is found to be the independent predictor for the occurrence of filter no reflow.

CONCLUSIONS

Adjunctive manual thrombus aspiration fails to reduce the filter no reflow, and probably has no additional benefit in saphenous vein graft lesions already protected by FilterWire EX/EZ.

Initial clinical experience with distal embolic protection using "Filtrap", a novel filter device with a self-expandable spiral basket in patients undergoing percutaneous coronary intervention

We developed a new filter-type distal protection guide wire, Filtrap, that uses a polyurethane filter with 1834 100-μm micropores covering the distal half of a spindle-shaped spiral Ni-Ti basket. The basket is 5 mm in diameter, self-expandable, and is mounted at the distal end of the system. This study aimed to assess the usefulness and safety of Filtrap during percutaneous coronary intervention (PCI). Early angiographic and in-hospital outcomes were reviewed in 14 patients, including 9 acute coronary syndrome patients, treated with Filtrap during PCI. All lesions were located in native coronary arteries but one was located in a saphenous vein graft. The Filtrap was successfully delivered and deployed distal to the lesion in 13 of 14 patients (93%). All PCI procedures including stent implantation were successfully completed except for 2 AMI patients, who ended up with Thrombolysis in Myocardial Infarction (TIMI) 2 coronary flow. One of these 2 patients had a distal embolization which occurred after thrombectomy before Filtrap insertion. The mean time of device insertion was 9.4 ± 3.2 min. Five patients showed transient no-reflow that was completely restored immediately with removal of the device. Embolic debris was entrapped in 8 (62%) of these cases. All patients were free from in-hospital events except for one patient with a large anterior acute myocardial infarction who received an emergency surgery due to a free wall cardiac rupture. These results suggest that the Filtrap is a practical and safe device for embolic protection during PCI.

Virtual histology by intravascular ultrasound study on degenerative aortocoronary saphenous vein grafts

Data of virtual histology (VH) acquired by intravascular ultrasound (IVUS) on saphenous vein graft (SVG) lesions is lacking. This study sought to report the VH IVUS findings in degenerative aortocoronary SVG lesions and correlate various types of plaque compositions (fibrous, fibro-fatty, dense calcium, and necrotic core) with different clinical and lesion characteristics. Virtual histology IVUS was performed on SVG in 38 symptomatic patients with a history of coronary artery bypass grafting, who underwent percutaneous coronary intervention on either native vessels or SVG. Measurements were made at the image slice with the smallest lumen. A total of 54 SVG lesions were analyzed; the mean graft age was 13.7 +/- 4.0 years. The mean vessel size was 5.0 +/- 1.0 mm; plaque area was 13.4 +/- 7.3 mm(2), and plaque burden was 63.0% +/- 15.0%. Fibrous tissue represented the major plaque component (62.1% +/- 17.1%). Lesions with a plaque burden of >or=70% were associated with positive remodeling, larger vessel size, higher percentage of fibro-fatty tissue, but lower percentage of dense calcium. Plaque burden was found to be positively correlated with remodeling index (r = 0.37, P = 0.01) and % fibro-fatty tissue (r = 0.49, P < 0.001) but negatively correlated with % dense calcium (r= -0.31, P = 0.03). The severity of SVG atherosclerosis paralleled with a proportional increase in fibro-fatty tissue. Unstable plaques in SVG were associated with positive remodeling, lipid-rich atheroma, and less calcium deposition, similar to the VH IVUS findings in native coronary arteries.

Contemporary incidence and predictors of major adverse cardiac events after saphenous vein graft intervention with embolic protection (an AMEthyst trial substudy)

The incidence and predictors of major adverse cardiac events after percutaneous coronary intervention of saphenous vein grafts have not been evaluated in the era of routine embolic protection device (EPD) use and the current standards of antiplatelet therapy. The Assessment of the Medtronic AVE Interceptor Saphenous Vein Graft Filter System (AMEthyst) is the largest randomized trial of vein graft intervention comparing the Interceptor EPD and either the GuardWire or FilterWire EPD as the control. The baseline demographic, procedural, and clinical characteristics and the 30-day major adverse cardiac events ([MACE] death, myocardial infarction, and repeat revascularization [either surgery or percutaneous coronary intervention] of the target vessel) were recorded for 748 patients who had undergone vein graft intervention with distal embolic protection. At 30 days, MACE had occurred in 58 patients (7.8%). The univariate predictors of MACE at 30 days included plaque volume (odds ratio 1.005/mm(3), p <0.0001), target lesion length (odds ratio 1.046/mm, p <0.001), vein graft degeneration score (odds ratio 1.631, p = 0.001), coronary narrowing classification (odds ratio 1.697, p = 0.004), reference vessel diameter (odds ratio 1.689, p = 0.004), and male gender (odds ratio 2.406, p = 0.046) and was independent of device type (p = 0.74). The plaque volume was the most important and only multivariate predictor of MACE. The highest quartile of plaque volume defined a subset at particular risk, despite EPD use (MACE 15.8% vs 5.0%, p <0.001). In conclusion, in a patient population in which EPD and preprocedure thienopyridine therapy were uniformly implemented, MACE occurred with an incidence of 7.8% at 30 days. An increasing plaque volume was the most important determinant of MACE and defined a population at particular risk.

Tranilast stabilizes the accumulation and degranulation of resident mast cells while reducing cardiomyocyte apoptosis in a swine model of coronary microembolisation

1. Coronary microembolisation (CME) is associated with progressive myocardial dysfunction, and mast cells (MC) might have an important role in myocardial apoptosis after CME. We investigated whether the MC stabilizer tranilast suppresses the accumulation and degranulation of MC while reducing cardiomyocyte apoptosis after CME. 2. We induced CME in miniswine by selective infusion of 15 x 10(4) microspheres (diameter 45 microm) into the left anterior descending artery. Some CME-induced miniswine were treated with the MC stabilizer tranilast (50 mg/kg, p.o., b.d.) beginning 2 weeks before CME, and thereafter throughout the experimental period; others received tranilast without CME; and sham-operated animals without CME served as controls. After 30 days, we assessed cardiomyocyte apoptosis by TUNEL assay and by the total number of MC and the number of degranulating MC using histology and transmission electron microscopy. The wall motion score index and left ventricular ejection fraction were studied by dobutamine stress echocardiography. 3. Coronary microembolisation was associated with increases in the total number of MC, the number of degranulating MC, and myocyte apoptosis. The number of total MC and degranulating MC and apoptotic cardiomyocytes over the anterior embolized myocardium after CME were significantly higher than those over the posterior control myocardium and anterior segments per animal without CME (P < 0.01). Tranilast administration to CME miniswine suppressed cardiomyocyte apoptosis while maintaining regional and global function, which was associated with reductions in the accumulation and degranulation of MC. 4. These findings suggest that tranilast suppresses the accumulation and degranulation of MC while reducing cardiomyocyte apoptosis after CME.

The results of a new distal protection method in intervention for chronic total occlusion of the superficial femoral artery

Aims. To determine the efficacy of a new distal protection method in SFA CTO interventions. Methods and Results. From June 2003 to February 2009, ninety-two consecutive, chronic total occlusions of superficial femoral arteries were treated with catheter-based intervention using a bidirectional approach. Nine of these cases were managed with our original, distal protection method, based on symptoms, angiographic images, wire resistance, and intravascular ultrasound images. The average age was 73 years; eight patients were male. The mean occlusion length was 17.1 cm. A distal protection balloon was inserted from the retrograde sheath in the popliteal artery and placed distal to the occluded lesion after successful wire crossing. Lesion dilatation with a balloon was performed antegradely and debris was removed by 6Fr. guiding catheter. Debris was retrieved from all lesions, consisting mainly of thrombus. Where we decided not to use the distal protection method, there was no distal thromboembolism. Conclusion. In SFA-CTO intervention, the risk of distal embolization is 10%, which can be anticipated and eliminated by the distal protection method.

Oral administration of glycine in the prevention of restenosis after coronary angioplasty. A double blind placebo controlled randomized feasibility trial evaluating safety and efficacy of glycine in the prevention of restenosis after angioplasty

OBJECTIVES

Evaluation of safety, feasibility, and efficacy of oral administered glycine in prevention of angiographic restenosis six months after percutaneous coronary intervention (PCI).

BACKGROUND

The amino acid glycine modulates immunological response and enhances the production of endothelial derived nitric oxide (EDNO) factor. This factor has been shown to possess anti-atherosclerotic properties, actions of which are thought to reduce neo-intimal hyperplasia. Furthermore, glycine significantly elevates arginine serum levels. This amino acid has been extensively studied for its effects on the endothelium, nitric oxide (NO) metabolism and effects on several biochemical pathways interfering with the process of restenosis after PCI.

METHODS

A prospective double blind placebo controlled randomized study evaluated safety and feasibility of chronic oral administration of glycine. In addition, the efficacy was determined by evaluation of six months angiographic restenosis rates.

RESULTS

214 patients scheduled for elective PCI were randomized to receive glycine or placebo. At follow-up, there was no significant difference in side effects and in major adverse cardiac events (MACE) between both groups. Six-month angiograms revealed similar restenosis rates for the glycine group (17.5%) and for the placebo group (20.2%) (P = 0.82).

CONCLUSION

Chronic oral administration of glycine was safe and feasible and had similar side effects compared to placebo. However, chronic oral administration of glycine did not lead to a significant reduction in restenosis rates at six months after elective PCI.

Embolic protection: Limitations of current technology and novel concepts

Distal embolic event is one of the major limitations of coronary and non-coronary vascular interventions. Balloon and filter-based Embolic Protection Devices (EPDs) are a new class of interventional devices, used to prevent consequential morbidity and mortality of the distal embolic events. Data from first generation EPD supply proof of concept and show approximately 40% reduction in mortality and morbidity, when EPDs are used during saphenous vein grafts (SVGs) interventions. Current limitations of all first generation EPD technology taper their penetration. With breakthroughs in embolic protection technology, it is estimated that, in the near future, EPDs will be used with stenting in all high-risk lesions (SVGs, carotid arteries and acute coronary syndromes), become the standard of care and even be used in low risk cases.

Clinical experiences using the FilterWire EX for distal embolic protection during complex percutaneous coronary interventions

BACKGROUND

Distal embolization during coronary angioplasty may result in vessel occlusion, no reflow and myonecrosis. This study tested the authors' clinical experiences using a guidewire system designed to preserve distal flow during angioplasty.

METHODS AND RESULTS

The FilterWire EX trade mark (Boston Scientific, Natick, MA, USA) consists of a 0.014-inch guidewire on which an expandable loop structure is attached to a porous polyurethane membrane. The assembly is delivered across the target lesion, followed by deployment of the filter distal to the lesion. Procedural and angiographic outcome data were obtained from patients undergoing saphenous vein grafts (SVGs) (n = 16) or native coronary (n = 4) interventions. The mean age was 62 +/- 10 years. All four patients with native coronary lesions sustained acute myocardial infarction while 15/16 patients with degenerated SVGs presented with accelerated angina pectoris. The mean proximal reference diameter was 3.62 +/- 0.32 mm, percentage diameter stenosis was 72 +/- 13%, and lesion length was 16.3 +/- 5.7 mm. Angiographic visible thrombus was detected in 12/20 (60%) cases. Stents were used in 19/20 patients (95%) with average stent diameter/length equal to 3.81 +/- 0.42/23 +/- 7 mm. Overall procedural success was obtained in 93.3% as no-reflow and total CK elevation occurred in 1/16 treated patients (6.7%) despite distal embolic filtration. In-hospital and 30-day survival was 100% with no episodes of target vessel thrombosis and/or myocardial infarction.

CONCLUSIONS

The use of the FilterWire EX seems to be feasible and safe in suitable lesion subsets and in relatively large-sized vessels among patients who are at high risk for distal embolization.

Comparison of myocardial reperfusion in patients with fasting blood glucose < or =100, 101 to 125, and >125 mg/dl and ST-elevation myocardial infarction with percutaneous coronary intervention

Diabetes and impaired fasting glucose (FG) were associated with worse outcomes in patients with acute myocardial infarction (MI). Because the underlying mechanism is not entirely clear, 376 consecutive patients with ST-elevation MI who underwent primary percutaneous coronary intervention (PPCI) were investigated. Patients were divided into 3 groups based on FG < or =100, FG of 101 to 125, and FG >125 mg/dl or previously diagnosed diabetes mellitus (DM) and studied for electrocardiographic signs of myocardial reperfusion (both spontaneous and after PPCI) and clinical outcomes. Clinical reperfusion was less likely with increasing FG: FG < or =100 mg/dl, 26%; FG of 101 to 125, 19%; and FG >125 and/or DM, 16% (p for trend = 0.03). Accordingly, angiographic TIMI grade 3 flow on initial angiography was 22% for FG < or =100 mg/dl, 13% for FG of 101 to 125, and 14% for FG >125 and/or DM (p for trend = 0.05). Despite similar TIMI flow after PPCI, early ST-segment resolution (> or =70%) was noted in 76%, 63%, and 60% in patients with FG < or =100 mg/dl, FG of 101 to 125, and FG >125 and/or DM, respectively (p for trend <0.01). Peak creatine phosphokinase (CPK) increased gradually, whereas left ventricular ejection fraction decreased with increased FG. Worse outcomes were observed with increasingly higher FG for heart failure (9%, 23%, and 26%; p for trend <0.01), cardiogenic shock (5%, 7%, and 13%; p for trend = 0.02), in-hospital mortality (1%, 2%, and 6%; p for trend = 0.01), and long-term mortality (2.5%, 4.5%, and 12%; p for trend <0.01) for patients with FG < or =100 mg/dl, FG of 101 to 125, and FG >125 and/or DM, respectively. In conclusion, increased FG and previously diagnosed DM were associated with less spontaneous reperfusion and less myocardial reperfusion after PPCI, resulting in worse clinical outcomes.

Microscopic and macroscopic evaluation of emboli captured during angioplasty and stent procedures in extracranial vertebral and internal carotid arteries

PURPOSE

To compare the quantities of emboli dislodged during percutaneous transluminal angioplasty/stenting in the vertebral artery (VA) with those released during stent placement in the internal carotid artery (ICA).

METHODS

Macroscopic images of distal protection devices (DPD) used during 30 stent procedures in 16 ICAs (11 men; mean age 64.6+/-10.6 years) and 14 VAs (9 men; mean age 67.1+/-9.8 years) were reviewed. The amount of captured embolic debris was calculated and expressed as a proportion to the size of the filter. Histological examinations were performed to characterize the material trapped in the filters.

RESULTS

Relative to the size of the filter, the proportion of captured debris ranged from 0.1% to approximately 22% in the ostial VA filters and from 0.1% to approximately 21% in the filters used in the ICA procedures (p = NS). Plaque fragments with or without thrombus were discovered in the histological examinations of captured material. There were no significant differences in the characteristics of the debris between the 2 vascular regions, nor did sex, race, or plaque morphology correlate significantly with the proportion of captured debris. However, the severity of stenosis was significantly (p<0.029) greater in the ICA (73%+/-0.11%) than the VA (63%+/-0.09%) territory.

CONCLUSION

The study suggests that the frequency and amount of captured emboli during stent procedures in ICA and ostial VAs are comparable. Therefore, the use of a DPD for stent placement in the vertebral artery may be advisable.

Procedural outcome and midterm result of carotid stenting in high-risk patients

Carotid endarterectomy is the standard treatment for carotid stenosis, but carotid artery stenting has emerged as a potential alternative. Elective carotid artery stenting was performed in 42 patients aged 42 to 79 years (mean, 67.05 +/- 8.67 years) after ultrasonography, computed tomography, magnetic resonance angiography and a neurological evaluation. There was bilateral carotid stenosis in 23 patients (55%), with > 90% stenosis in 18 vessels. All patients had significant associated coronary lesions. An emboli protection device and self-expanding stents were used. One year later, the patients were evaluated by Doppler sonography and selective angiography. Technical success was achieved in all procedures. During follow-up, 1 (2.4%) patient died from myocardial infarction, 1 underwent coronary artery bypass and 14 (40%) had minor complaints including occasional dizziness. No other neurological events were noted. Restenosis was found in one case, but selective angiography ruled out a significant lesion. One patient suffered embolization, but recovered completely within 24 hours. In 7 (17%) patients with type C arch interruption and a tortuous carotid course, stenting was successful and they had no embolization or restenosis. Carotid artery stenting is recommended in high-risk patients.

New universal definition of myocardial infarction: What is the difference?

<zakljucak> Ucinjene su brojne izmene univerzalne definicije infarkta miokarda u odnosu na verziju iz 2000. godine, ali troponin ostaje zlatni standard za opstu definiciju u miljeu karakteristicnog klinickog scenarija za ishemiju miokarda i tipicnih EKG promena. Svako povecanje troponina ne znaci istovremeno i definitivno infarkt miokarda. Postoje i mnogi drugi uzroci porasta troponina. Nekroza miokarda nije uvek posledica ishemije, vec postoje i druge nokse koje mogu dovesti do smrti celija miokarda. U novim preporukama navodi se da je troponin 'izabrani' marker, ali i drugi biomarkeri, pre svega MB frakcija kreatinin kinaze, mogu biti dovoljni, ako nije dostupan test sa troponinom. Ostale inovacije ukljucuju kriterijume za infarkt miokarda kao uzrocnika naprasne smrti i posebna tezina koja se daje nalazima dobijenim ehokardiografski, perfuzionom scintigrafijom i ostalim neinvazivnim metodama. Jedan od ciljeva ovog konsenzusa je da se utvrde specificni kriterijumi za postavljenje dijagnoze infarkta miokarda koji ce biti moderni, prakticni i relevantni u svakoj prilici sirom sveta. Ideja je bila da se definicija standardizuje tako da sve klinicke studije i svi ljudi u bolnicama sirom sveta budu 'na istoj talasnoj duzini'.

Carotid artery stenting in octogenarians is associated with increased adverse outcomes

BACKGROUND

Carotid artery stenting is an increasingly common endovascular treatment of carotid artery stenosis advocated in high-risk patients despite reports of increased adverse periprocedural outcomes in patients aged >80 years. We sought to evaluate our single institution experience with octogenarians and whether they have an increased incidence of major complications with carotid artery stenting.

METHODS

Three hundred eighty-six patients, including 260 patients from 10 regulatory trials, who underwent carotid artery stenting between June 1996 and March 2004 for symptomatic or asymptomatic carotid stenosis were reviewed from a prospectively maintained database. Periprocedural (< or =30 days after carotid artery stenting) cerebrovascular accident, transient ischemic attack, myocardial infarction, and death outcomes were compared between 87 octogenarians and 295 nonoctogenarians. Univariate and multivariate analysis was performed for confounding factors. Kaplan-Meier analysis of stroke and death outcomes was performed for a 1-year follow-up.

RESULTS

All adverse outcomes were significantly higher in octogenarians compared with younger patients: 30-day stroke rate, 8.0% vs 2.7% (P = .02); 30-day stroke, myocardial infarction, or death, 9.2% vs 3.4% (P = .02). Cohorts were similar in terms of gender, comorbidities, antiplatelet medications, symptomatic status, and use of cerebral protection. Octogenarians had a greater incidence of contralateral internal carotid artery occlusion (26% vs 12%, P = .001), atrial fibrillation (21% vs 8%, P = .001), and congestive heart failure (28% vs 15%, P = .007), but a lower incidence of hypercholesterolemia (53% vs 72%, P = .001) and active smoking (8% vs 24%, P = .001). Multivariate analysis of 30-day major adverse outcomes demonstrated an association between age > or =80 and adverse outcome (odds ratio, 2.85; P = .043) as well as a protective effect of the preprocedural use of aspirin (odds ratio, 0.30, P = .027). At 1-year follow-up, only 75% of octogenarians and 87% of nonoctogenarians were free from stroke, myocardial infarction, or death (P = 005, Kaplan-Meier analysis).

CONCLUSIONS

Octogenarians undergoing carotid artery stenting are at higher risk than nonoctogenarians for periprocedural complications, including neurologic events and death. Major event-free survival at 1 year is also significantly better in nonoctogenarians. These risks should be weighed when considering carotid stenting in elderly patients.

Coronary microembolization

Atherosclerotic plaque rupture is the key event in the pathogenesis of acute coronary syndromes and it also occurs during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the epicardial coronary artery with subsequent impending myocardial infarction, but may in milder forms result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. This review summarizes the present experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and highlights the main consequences of coronary microembolization--reduced coronary reserve, microinfarction, inflammation and oxidative modification of contractile proteins, contractile dysfunction and perfusion-contraction mismatch.Furthermore, the review presents the available clinical evidence for coronary microembolization in patients and compares the clinical observations with observations in the experimental model.

Coronary Arterial Plaque Characterized by Multislice Computed Tomography Predicts Complications Following Coronary Intervention

BACKGROUND

A reliable, noninvasive assessment of plaque configuration would constitute an important step forward for predicting complications following percutaneous coronary intervention (PCI). Multislice computed tomography (MSCT) holds promise with respect to allowing for differentiation of coronary lesion configuration. However, it has not yet been clarified whether the characteristics of coronary artery plaque measured by MSCT predict complications after PCI. The aim of this study was to investigate the relationship between plaque configuration and complications after coronary intervention in patients with stable angina pectoris.

METHODS

MSCT was performed in patients with angina pectoris who were scheduled for PCI prospectively, and 26 patients (70 +/- 11 years, 18 males) with coronary artery plaque in a stenotic coronary artery measured by MSCT were recruited for this study. Thirty-five plaques in the stenotic coronary lesions were divided into 3 groups based on the CT density as soft, intermediate, and hard, and were compared with the complications after PCI.

RESULTS

The soft plaque group before PCI (n = 11) was significantly associated with the appearance of slow flow (n = 4) or a compromised side branch (n = 1) after PCI, whereas the hard plaque group before PCI (n = 17) was associated with the appearance of dissection (n = 2) or perforation (n = 1) after PCI (P = 0.004). The intermediate plaque group (n = 7) had only one complication, a compromised side branch (n = 1).

CONCLUSION

Coronary arterial plaque characterized by MSCT can predict intervention-related complication. It may be important for the risk stratification of the patients scheduled to undergo PCI to investigate plaque configuration by MSCT.

New distal embolic protection device the FiberNet® 3 dimensional filter: First carotid human study

OBJECTIVE

Evaluate the performance and safety of the FiberNet Embolic Protection System during carotid artery intervention.

BACKGROUND

Carotid Angioplasty and Stenting (CAS) can be proposed to treat the majority of carotid stenoses. Brain embolization takes place and routine use of Embolic Protection Devices (EPD) is warranted. Many EPDs have significant limitations, which may be addressed by a new EPD, the FiberNet (Lumen Biomedical, Plymouth, MN).

METHODS

The system consists of a 3-dimensional expandable filter made of fibers, which expand radially, mounted onto a 0.014'' wire and retrieval catheter. FiberNet can capture particles as small as 40 microm without compromising flow.

RESULTS

35 lesions treated in 34 patients. Male 67.6%. Age: 71.4 +/- 8.8 (50-85). Average stenosis 84.5% +/- 7.9 (70-99). 29.4% were symptomatic. Technical success: 34/35 (97%). No stroke or death within 30 days. Neurological events: two permanent amaurosis, one amaurosis fugax. All samples visually contained significant amounts of emboli. The mean surface area of debris caught was 63.8 mm(2) (37.7-107.5). Comparisons were made with other EPDs. The mean surface area of debris caught was 12.2 mm(2) (2.7-34.3). No changes were noted in CT/MRI at 30-day post procedure.

CONCLUSION

The first human use of this new novel EPD in carotid artery stenting is encouraging. The FiberNet was easy to use and confirmed the ability to capture particles less than 100 microm. The feasibility of the FiberNet has been demonstrated. Additional patients will demonstrate the overall safety and efficacy of this new EPD device.