Angiographic evolution of coronary artery morphology in unstable angina

Prognostic Value of Multiple Complete Blood Count-Derived Indices in Intermediate Coronary Lesions

Complete blood count (CBC)-derived indices have been proposed as reliable inflammatory biomarkers to predict outcomes in the context of coronary artery disease. These indices have yet to be thoroughly validated in patients with intermediate coronary stenosis. Our study included 1527 patients only with intermediate coronary stenosis. The examined variables were neutrophil-lymphocyte ratio (NLR), derived NLR, monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), systemic immune inflammation index (SII), system inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI). The primary endpoint was the composite of major adverse cardiovascular events (MACEs), including all-cause death, non-fatal myocardial infarction, and unplanned revascularization. Over a follow-up of 6.11 (5.73-6.55) years, MACEs occurred in 189 patients. Receiver operator characteristic curve analysis showed that SIRI outperformed other indices with the most significant area under the curve. In the multivariable analysis, SIRI (hazard ratio [HR] 1.588, 95% confidence interval [CI] 1.138-2.212) and AISI (HR 1.673, 95% CI 1.217-2.300) were the most important prognostic factors among all the indices. The discrimination ability of each index was strengthened in patients with less burden of modifiable cardiovascular risk factors. SIRI also exhibited the best incremental value beyond the traditional cardiovascular risk model.

In Search of Coronary Thrombosis as the Cause of Myocardial Infarction: Unraveling a 20th-Century Mystery

For the greater part of the 20th century, the pathophysiology of acute myocardial infarction regarding whether thrombosis was either present or primary was debated until 1973 when pathologists and clinicians met and by consensus, finally decided that the data supported that transmural infarction (what we now refer to as ST elevation myocardial infarction or STEMI) was caused by thrombus in the vessel supplying the infarcted territory. As the data for this consensus came from pathological analysis, it took another 7 years until angiographic and interventional data in humans with acute presentations of transmural infarction convincingly indicated that thrombus was indeed responsible. Subsequently, in patients presenting with either syndromes of unstable angina or nontransmural (later called non-ST elevation) myocardial infarction, it was established through angiographic and other interventional approaches that thrombus formation was also causative in a substantial proportion of these patients. This article reviews the history and this search for causation of myocardial infarction that now has resulted in present therapies that have saved innumerable lives over the last 30 to 40 years.

Multi-modality intravascular imaging for guiding coronary intervention and assessing coronary atheroma: the Novasight Hybrid IVUS-OCT system

Intravascular imaging has evolved alongside interventional cardiology as an adjunctive tool for assessing plaque pathology and for guiding and optimising percutaneous coronary intervention (PCI) in challenging lesions. The two modalities which have dominated the field are intravascular ultrasound (IVUS), which relies on sound waves and optical coherence tomography (OCT), relying on light waves. These approaches however have limited efficacy in assessing plaque morphology and vulnerability that are essential for guiding PCI in complex lesions and identifying patient at risk that will benefit from emerging therapies targeting plaque evolution. These limitations are complementary and, in this context, it has been recognised and demonstrated in multi-modality studies that the concurrent use of IVUS and OCT can help overcome these deficits enabling a more complete and accurate plaque assessment. The Conavi Novasight Hybrid IVUS-OCT catheter is the first commercially available device that is capable of invasive clinical coronary assessment with simultaneously acquired and co-registered IVUS and OCT imaging. It represents a significant evolution in the field and is expected to have broad application in clinical practice and research. In this review article we present the limitations of standalone intravascular imaging techniques, summarise the data supporting the value of multimodality imaging in clinical practice and research, describe the Novasight Hybrid IVUS-OCT system and highlight the potential utility of this technology in coronary intervention and in the study of atherosclerosis.

Low Plasma Adiponectin Levels Are Associated With Vulnerable Plaque Features in Patients With Acute Coronary Syndrome: An Optical Coherence Tomography Study

BACKGROUND

Vulnerable plaques are the primary cause of acute coronary syndrome (ACS). The association between in-vivo plaque vulnerability and adiponectin levels in ACS still remains to be determined.

OBJECTIVE

The purpose of this study was to investigate the correlation between adiponectin levels and vulnerable plaque features in ACS patients.

METHODS

We enrolled 107 ACS patients admitted to our institution; 83 with Non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation myocardial infarction (STEMI). Adiponectin levels were measured in these patients. Coronary angiography and subsequent optical coherence tomography (OCT) analysis of culprit lesions were performed.

RESULTS

Adiponectin level was lower in patients with complex angiographic lesions, compared to those with non-complex lesions (7.13 ± 3.04 vs. 8.94 ± 2.84 μg/ml, P = 0.002). Adiponectin level was lower in patients with plaque rupture (PR), micro-thrombi, and thin cap fibroatheroma (TCFA), compared to those with non-vulnerable features (7.19 ± 2.95 vs 8.79 ± 3.02 μg/ml, P = 0.007 & 7.29 ± 2.97 vs 8.44 ± 3.09 μg/ml, P = 0.04 and 4.76 ± 0.65 vs 9.74 ± 2.35 μg/ml, P < 0.001 μg/ml respectively). There was a significant negative correlation between adiponectin levels and lipid rich plaque extent and maximum lipid arc (r = -0.05, P < 0.001 & r = -0.03, P = 0.03, respectively). However, a significant positive correlation was observed between adiponectin levels and fibrous cap thickness (r = 0.95, P < 0.001).

CONCLUSION

Low adiponectin levels were associated with complex angiographic lesions and vulnerable plaque features in ACS patients, where there was a significant correlation between it and PR, TCFA, and lipid rich plaque.

Prevalence and clinical significance of totally occluded infarct-related arteries in patients with non-ST-segment elevation acute coronary syndromes

Background Seemingly conflicting findings exist regarding the prognostic impact of totally occluded infarct-related arteries (oIRA) in non-ST elevation acute coronary syndromes (NSTE-ACS). Methods Retrospective analysis of prospective multicenter registry data comprising a single-center NSTE-ACS cohort, aimed at assessing the impact of occluded (TIMI flow 0/1) versus patent culprit vessels (pIRA, TIMI flow 2/3) on the composite endpoint of all-cause death and cardiogenic shock events at 30 days. Results Of 568 patients, 183 (32.5%) had oIRA. Male sex, refractory angina, ECG suggestive of multivessel or left main disease, and larger infarct sizes with inferior/posterolateral wall involvement, were identified as highly specific markers of oIRA. Successful culprit-lesion revascularization occurred more frequently in patent than in oIRA (90% vs. 96%; P = 0.013). Conversely, patients with oIRA more frequently achieved successful revascularization of concurrent non-IRAs including chronic total occlusions than did those with pIRA (28% vs. 3%; P = 0.0005). Multivariate analysis revealed neutral effects of oIRA on outcomes and identified incomplete revascularization as a powerful predictor of mortality. Moderation analysis revealed a significant interaction between completeness of revascularization and IRA patency, whereby among the incompletely revascularized patients, those with oIRA enjoyed a significant survival advantage over their counterparts with pIRA (11.8% vs. 28%, adjusted OR 0.34; 95% CI 0.10-0.73; P_interaction = 0.012). Conclusions Approximately one third of NSTE-ACS patients in this cohort had oIRA. However, compared with pIRA, the occurrence of oIRA did not portend poor outcomes, likely resulting from the higher rate of incomplete revascularization and increased risk of subsequent mortality in patients with pIRA. These exploratory findings warrant further investigation.

Clinical outcome according to spasm type of single coronary artery provoked by intracoronary ergonovine tests in patients without significant organic stenosis

BACKGROUND

This study aimed to evaluate clinical implications of single vessel coronary spasm provoked by intracoronary ergonovine provocation test in Korean population.

METHOD

A total of 1248 patients who presented with single vessel coronary artery spasm induced by intracoronary ergonovine provocation test, excluding 1712 with negative spasms, multiple and mixed coronary artery spasms and missing data among 2960 patients in the VA-KOREA (Vasospastic Angina in Korea) registry, were classified into diffuse (n=705) and focal (n=543) groups.

RESULTS

The 24-month incidences of a composite primary endpoints (cardiac death, new-onset arrhythmia, and acute coronary syndrome) were determined. Over a median follow-up of 30months, the composite primary end point occurred more frequently in the focal type patients than in the diffuse type patients (primary endpoint: adjusted hazard ratio [aHR], 1.658; 95% confidence interval [CI] 1.272 to 2.162, P<0.001). Especially, unstable angina in ACS components played a major role in this effect (hazard ratio [HR], 2.365; 95% confidence interval [CI] 1.100 to 5.087, P=0.028).

CONCLUSION

Focal type of single vessel coronary artery spasm in vasospastic angina (VSA) patients is found to be associated with worse clinical outcomes. It is thought that the effect is stemmed from unstable angina among ACS rather than the other components of primary endpoint. Therefore, focal type of single vessel coronary artery spasm in patients with VSA should be more carefully assessed and managed with appropriate medication.

Presence of multiple coronary angiographic characteristics for the diagnosis of acute coronary thrombus

BACKGROUND

Coronary angiography is frequently employed to aid in the diagnosis of acute coronary thrombosis, but there is limited data to support its efficacy. The aim of the study was to evaluate sensitivity and specificity of five commonly used angiographic characteristics for diagnosis of acute coronary thrombosis: Ambrose complex lesion morphology; spherical, ovoid, or irregular filling defect; abrupt vessel cutoff; intraluminal staining; and any coronary filling defect.

METHODS

Coronary angiography of 80 acute myocardial infarction or stable coronary artery disease subjects were assessed in blinded fashion, for the presence or absence of five angiographic characteristics. Only lesions of ≥ 10% stenosis were included in the analysis. Presence or absence of each angiographic characteristic was compared between lesions with or without the following study defined outcomes: 1) histologically confirmed thrombus, 2) highly probable thrombus, and 3) highly unlikely thrombus.

RESULTS

A total of 323 lesions were evaluated. All studied angiographic characteristics were associated with histologically confirmed and highly probable thrombotic lesions vs. lesions not meeting criteria for these outcomes (p < 0.03), except for complex Ambrose morphology which was not associated with any of the study outcomes (p > 0.05). Specificity for identifying histologically confirmed or highly probable thrombotic lesion was high (92-100%), especially for spherical, ovoid, or irregular filling defect (99-100%) and intraluminal staining (99%). Sensitivity for identification of histologically confirmed or highly probable thrombotic lesions was low for all tested angiographic characteristics (17-60%).

CONCLUSIONS

The presence of spherical, ovoid, or irregular filling defect or intraluminal staining was highly suggestive of coronary thrombus. However, none of the evaluated angiographic characteristics were useful for ruling out the presence of coronary thrombus. If confirmed in an independent cohort, these angiographic characteristic will be of significant value in confirming the diagnosis of acute coronary thrombosis.

Therapy of unstable angina with the low molecular weight heparins

Unstable angina is in most cases caused by partial or complete coronary artery occlusion due to the disruption of an atherosclerotic plaque and to thrombus formation. An immediate antithrombotic approach is essential to prevent fatal and non-fatal myocardial infarction, and the combination of aspirin and unfractionated heparin has played a pivotal role in the past years. Low molecular weight heparins have improved pharmacokinetic and pharmaco-dynamic properties over unfractionated heparin that have resulted in greater efficacy and safety in the field of venous thromboembolism. Low molecular weight heparins can be administered by once or twice daily subcutaneous injections at fixed, weight-adjusted doses without the need for monitoring. Because of their potential, many recent clinical trials have evaluated their efficacy and safety in the management of patients with unstable angina. Three low molecular weight heparins have so far been tested: nadroparin, dalteparin and enoxaparin. The results of the published trials confirm that the newer compounds are at least as safe and effective as unfractionated heparin, and offer considerable therapeutic advantages. Nevertheless, the different properties of the three compounds and perhaps the different designs of the clinical trials have led to not entirely comparable findings.

Serum macrophage migration inhibitory factor levels are associated with angiographically complex coronary lesions in patients with coronary artery disease

BACKGROUND

Rupture of vulnerable plaque with subsequent thrombus formation has been implicated as the most common pathogenic mechanism responsible for acute coronary syndrome (ACS). Angiographic coronary lesion complexity has been reported to reflect plaque vulnerability. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine and might be involved in the pathophysiology of atherosclerotic plaque destabilization.

OBJECTIVE

This study was designed to investigate if serum MIF levels are associated with angiographic coronary lesion complexity in patients with coronary artery disease (CAD).

MATERIALS AND METHODS

A total of 232 consecutive CAD patients and 76 controls were recruited. CAD patients were subdivided according to the presence of ACS (n=138) or stable angina pectoris (SAP) (n=98). Coronary lesion morphology was assessed by coronary angiography. Serum MIF levels were measured by an enzyme-linked immunosorbent assay.

RESULTS

SAP patients had significantly higher serum MIF levels compared with healthy controls, and ACS patients had significantly higher serum MIF levels compared with SAP patients. In SAP patients, serum MIF levels were independently associated with the presence of complex coronary lesion. In ACS patients, serum MIF levels increased in conjunction with the extent of complex lesions.

CONCLUSIONS

Serum MIF levels are a potential biomarker for reflecting the presence and severity of angiographically complex coronary lesion in CAD patients.

Arteriosclerosis: facts and fancy

Arterial vascular diseases comprise the leading cause of death in the industrialized world. Every physician learns about the pathology of these diseases in medical school. All pathologists evaluate arterial disease in surgical pathology and/or autopsy specimens. All clinicians encounter patients with clinical manifestations of these diseases. With such a common and clinically-important group of entities one would think there would be a general understanding of the "known" information that exists. That is, physicians and scientists should be able to separate what is fact and what is fancy. This review article is intended to generate thought in this regard.

Optical coherence tomography features of angiographic complex and smooth lesions in acute coronary syndromes

Plaque rupture (PR) and superimposed thrombosis have been shown as the most frequent underlying substrate in acute coronary syndromes (ACS). Coronary angiography is a luminogram not able to define in vivo features of the culprit plaques. The aim of the study was to use optical coherence tomography (OCT) to investigate the pathology underlying complex (CL) and non-complex angiographic lesions (NCL). We retrospectively enrolled 107 ACS patients admitted to our institution; 83 with non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation myocardial infarction. Coronary angiography was performed and culprit lesions were classified according to Ambrose criteria into NCL (n = 47) and CL (n = 60). OCT imaging was then performed to better identify plaque morphology; either PR or intact fibrous cap, the presence of superimposed thrombosis, lipid rich plaque, and thin cap fibroatheroma (TCFA). OCT analysis showed that 58 lesions (54.2%) were classified as PR and 48 lesions (44.9%) were associated with thrombi. Lipid rich plaques were identified in 62 lesions (57.9%). PR, intracoronary thrombi, lipid rich plaques and TCFA were more frequent in CL compared with NCL (71.7 vs 31.9%, 63.3 vs 21.3%, 71.7 vs 40.4% and 46.7 vs 21.3% respectively), but PR with superimposed thrombus may be also detected in NCL. OCT demonstrates PR and thrombosis in the majority of ACS patients presenting with CL. However, one-third of NCL show PR by OCT, suggesting that additional intracoronary imaging by OCT may better identify the underlying mechanism of coronary instability than coronary angiography alone.

Understanding the role of B cells in atherosclerosis: potential clinical implications

Atherosclerosis is a progressive inflammatory disease of the medium to large arteries that is the largest contributor to cardiovascular disease. B-cell subsets have been shown in animal models of atherosclerosis to have both atherogenic and atheroprotective properties. In this review, we highlight the research that developed our understanding of the role of B cells in atherosclerosis both in humans and mice. From this we discuss the potential clinical impact B cells could have both as diagnostic biomarkers and as targets for immunotherapy. Finally, we recognize the inherent difficulty in translating findings from animal models into humans given the differences in both cardiovascular disease and the immune system between mice and humans, making the case for greater efforts at addressing the role of B cells in human atherosclerosis.

Recent progress in the treatment of cardiovascular disease using olmesartan

Angiotensin II (Ang II) evokes inflammatory responses and plays a central role in atherosclerosis mediated by Ang II type 1 (AT1) receptor. AT1 receptor blockers (ARBs) prevent the diverse effects of Ang II. Unique molecule-specific, or off-target effects of ARBs are due to their slightly different structures, although all ARBs have common, or class, effects. In nonsignificant coronary stenotic lesions, it is important that we use aggressive medical treatments using ARBs in addition to statins and oral hypoglycemic agents, to induce the regression and stabilization of coronary plaque. This review focuses on current evidence regarding the molecule-specific effects of ARB olmesartan to prevent the increase in coronary atheroma volume.

Prognosis of patients with mild-moderate coronary artery stenosis detected by coronary computed tomography angiography

BACKGROUND

In addition to the diagnostic performance, coronary computed tomography angiography (CTA) can give important data regarding the prognosis of coronary artery disease (CAD). In this study we aimed to evaluate the prognostic role of coronary CTA in patients with suspected CAD and mild-moderate coronary stenosis.

METHODS

A total of 1115 patients (602 male, 54%; age 58.4 ± 11.4) without previous CAD were enrolled. Patients underwent coronary CTA imaging using dual-source 64-slice CT scanner. For categorization of the coronary atherosclerotic plaques (CAP), the coronary system was divided into 16 separate segments. For each segment, CAPs were categorized as: calcified, noncalcified and mixed.

RESULTS

During follow-up of 29.7 ± 13.2 months, cardiovascular events defined as ST segment elevation myocardial infarction (4 patients), non-ST segment elevation myocardial infarction (5 patients) and unstable angina pectoris (20 patients) requiring revascularization or hospital admission were recorded. Cox hazard regression analysis revealed an association between the severity of luminal stenosis (HR: 4.73, 95% CI: 1.36-16.47, p<0.05) and extent (HR: 1.10, 95% CI: 1.00-1.22, p=0.051) and the adverse coronary events in the follow-up. Multivariate Cox hazard regression analysis revealed that nonobstructive (≤ 50%) lesions were the only factor causing increased probability of coronary events in the follow-up (HR: 4.77, 95% CI: 1.36-16.74, p<0.05).

CONCLUSION

The presence and severity of luminal stenosis shown by coronary CTA were associated with prognosis of coronary events in the follow-up. These results may improve the risk stratification in patients evaluated by coronary CTA and provide strategies for the individualized prevention programs.

Histopathologic characteristics of atherosclerotic coronary disease and implications of the findings for the invasive and noninvasive detection of vulnerable plaques

OBJECTIVES

The goal of this study was to identify histomorphologic characteristics of atherosclerotic plaques and to determine the amenability of some of these components to be used as markers for invasive and noninvasive imaging.

BACKGROUND

Rupture of the atherosclerotic plaques is responsible for the majority of acute coronary events, and the culprit lesions demonstrate distinct histopathologic features. It has been tacitly believed that plaque rupture (PR) is associated with angiographically minimally occlusive lesions.

METHODS

We obtained 295 coronary atherosclerotic plaques, including stable (fibroatheroma [FA]; n = 105), vulnerable (thin-cap fibroatheroma [TCFA]; n = 88), and disrupted plaques (plaque rupture [PR]; n = 102) from the hearts of 181 men and 32 women who had died suddenly. The hierarchical importance of fibrous cap thickness, percent luminal stenosis, macrophage area, necrotic core area, and calcified plaque area was evaluated by using recursive partitioning analysis. Because clinical assessment of fibrous cap thickness is not possible by noninvasive imaging, it was excluded from the second set of partitioning analysis.

RESULTS

Thickness of the fibrous cap emerged as the best discriminator of plaque type; the cap thickness measured <55 μm in ruptured plaques, and all FA were associated with >84-μm cap thickness. Although the majority of TCFA were found in the 54- to 84-μm thickness group, those with <54-μm thickness were more likely to show <74% luminal stenosis (area under the curve: FA, 1.0; TCFA, 0.89; PR, 0.90). After exclusion of cap thickness, analysis of the plaque characteristics revealed macrophage infiltration and necrotic core to be the 2 best discriminators of plaque types (area under the curve: FA, 0.82; TCFA, 0.58; PR, 0.72). More than 75% cross-section area stenosis was seen in 70% of PR and 40% of TCFA; only 5% PR and 10% TCFA were <50% narrowed.

CONCLUSIONS

This postmortem study defines histomorphologic characteristics of vulnerable plaques, which may help develop imaging strategies for identification of such plaques in patients at a high risk of sustaining acute coronary events.

Multimarker approach for the prediction of cardiovascular events in patients with mild to moderate coronary artery lesions. A 3-year follow-up study

Few studies have assessed the incremental usefulness of multimarkers as predictors of cardiovascular events in patients with mild to moderate coronary artery lesions.We examined 9 plasma inflammatory cytokines (cathepsin S, CXCL16, sopluble CD40 ligand, interleukin-10, placental growth factor, GDF15, matrix metalloproteinase 9, monocyte chemoattractant protein-1, and high-sensitivity C-reactive protein) in 964 patients showing mild to moderate lesions and assessed their association with risk of cardiovascular events during 3 years of follow-up (median 17 months).In a backward Cox regression procedure, Cystatin S (hazard ratio [HR]: 1.788, 95% CI: 1.233 to 2.593, P = 0.02), soluble CD40 ligand (HR: 1.255, 95% CI: 1.054 to 1.494, P = 0.011), placental growth factor (HR: 1.194, 95% CI: 0.976 to 1.461, P = 0.035), and GDF15 (HR: 0.725, 95% CI: 0.550 to 0.956, P = 0.023) were significantly related to cardiovascular events. Compared with multimarker score (according to regression coefficients of significant biomarkers) in the lowest two quintiles, patients in the highest quintile had a higher risk of cardiovascular events after adjustment for traditional risk factors (HR: 2.77, 95% CI: 1.30 to 5.87, P = 0.008). Adding the multimarker score to traditional risk factors contributed significantly to the prediction of cardiovascular events (AUC increased from 0.67 to 0.72).A multimarker approach added to the predictive information obtained from traditional risk factors in patients with mild to moderate coronary artery lesions.

Pathophysiology of coronary thrombus formation and adverse consequences of thrombus during PCI

Atherosclerosis is a systemic vascular pathology that is preceded by endothelial dysfunction. Vascular inflammation "fuels" atherosclerosis and creates the milieu for episodes of intravascular thromboses. Thrombotic events in the coronary vasculature may lead to asymptomatic progression of atherosclerosis or could manifest as acute coronary syndromes or even sudden cardiac death. Thrombus encountered in the setting of acute coronary syndromes has been correlated with acute complications during percutaneous coronary interventions such as no-reflow, acute coronary occlusion and long term complications such as stent thrombus. This article reviews the pathophysiology of coronary thrombogenesis and explores the complications associated with thrombus during coronary interventions.

A comparison of intracoronary with intravenous glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention in patients with acute coronary syndrome: a meta-analysis of randomized controlled trials

BACKGROUND

It is still debatable whether intracoronary (IC) administration of glycoprotein IIb/IIIa inhibitors (GPIs) is superior to intravenous (IV) administration for patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI).

METHODS

We performed a meta-analysis of randomized controlled clinical trials. A literature search was conducted for relevant trials. Primary end-points were short-term (1-3 months) and mid-/long-term (6/12 months) major adverse cardiovascular events (MACEs) (mortality, reinfarction, target vessel revascularization [TVR]). Secondary end-points were thrombolysis in myocardial infarction (TIMI) grade flow, TIMI myocardial perfusion grade (TMPG) flow, left ventricular ejection fraction (LVEF) within 2 weeks, and bleeding complication.

RESULTS

Twelve studies were included in the meta-analysis. IC administration of GPIs did not decrease short-term mortality (OR: 0.71, 95% CI: 0.41-1.23, P = 0.22) and reinfarction rate (OR: 0.76, 95% CI: 0.45-1.29, P = 0.31) compared with IV administration. There was a trend toward reduction of short-term TVR rate in IC group compared with IV group but not reaching statistical significance (OR: 0.57, 95% CI: 0.31-1.04, P = 0.07). IC administration of GPIs significantly increased TIMI grade 3 flow (OR: 1.48, 95% CI: 1.06-2.06, P = 0.02) and TMPG grade 2-3 flow (OR: 2.63, 95% CI: 1.53-4.51, P = 0.0004) compared with IV administration. No significant difference was observed in long-term MACEs rate, LVEF, and bleeding complication between the 2 groups.

CONCLUSION

IC administration of GPIs in patients with ACS undergoing PCI can significantly increase target coronary flow and myocardial reperfusion without increasing the risk of bleeding complication, but cannot improve clinical outcome compared with IV administration.

Imaging assessment of cardiovascular risk in asymptomatic adults

OBJECTIVE

This article will address the role of coronary artery calcium (CAC) and carotid intima-media thickness screening in asymptomatic at-risk adults and the broader concept of vulnerable plaque as it applies to this population.

CONCLUSION

Imaging for assessment of cardiovascular risk in asymptomatic adults has been the subject of considerable interest and some controversy. The incorporation of CAC and carotid intima-media thickness assessment into recent guidelines reflects the growing evidence base for these applications.

Noncalcified plaque: relationship between results of multislice computed tomography, risk factors, and late clinical outcome

BACKGROUND

Contrast-enhanced multislice computed tomographic angiography (MSCTA) detects noncalcified plaque (NCP) in coronary arteries and associated coronary stenoses. However, the clinical relevance of NCP is poorly defined.

OBJECTIVES

Our goal was to examine the relationship NCP, risk factors (RFs), and clinical follow-up in unselected outpatients undergoing MSCTA.

METHODS

Five hundred six patients undergoing contrast MSCTA were evaluated for NCP (intraluminal density 25 < Hounsfield units < 130). One hundred twenty-four patients (24.5%) had calcium scores (CAC) of zero. Of these, 111 patients were examined for RFs and followed clinically for a mean of 34 months.

RESULTS

Of 124 patients with zero CAC, 111 (89.5%) included 52 (46.8%) with no NCP, 40 (36.0%) with NCP, and mild luminal stenosis, 14 (12.6%) and 5 (4.5%) with NCP causing significant and severe stenosis, respectively. Patients in each group were similar in age but differed significantly in number of RFs. Current or former smokers, hypertensive, and obese patients had more NCP and associated stenosis. At a mean of 34 months, there were no events in the no NCP group, 2/54 (3.7%) events in the NCP without severe stenosis group (one sudden cardiac death and one ventricular tachycardia), and 2/5 (40.0%) patients had revascularization in the NCP with severe stenosis group.

CONCLUSIONS

(1) In patients with zero CAC, presence of NCP on MSCTA was associated with more RFs, especially smoking, obesity, and hypertension. (2) NCP can result in severe coronary stenosis. (3) NCP detected by MSCTA in patients with zero CAC may identify patients with late cardiac events.

Coronary multidetector computed tomographic angiography to evaluate coronary artery disease in liver transplant candidates: methods, feasibility and initial experience

AIMS

In patients undergoing orthotopic liver transplantation (OLT), coronary artery disease (CAD), obstructive and nonobstructive, is associated with high morbidity and mortality. In OLT candidates, stress testing for detecting ischemia is often inaccurate, and this patient population often has relative contraindications for cardiac catheterization. The objective of this study was to describe the methods, assess the feasibility and determine the extent and severity of CAD in OLT candidates without a prior history of CAD using coronary multidetector computer tomographic angiography (MDCTA).

METHODS

Sixty-five OLT candidates without known CAD underwent coronary MDCTA with dual source cardiac computed tomography (Siemens Definition). Coronary arteries were divided into 17 segments based on American Heart Association guidelines and evaluated independently by two blinded reviewers. Image quality of coronary MDCTA was assessed on a four-point Likert scale (0 = poor, 1 = fair, 2 = good, and 3 = excellent). Atherosclerotic lesions were evaluated for severity [mild (0-50%), moderate (51-70%), and severe (71-100%)], morphology, extent, location and consistency.

RESULTS

Image quality was graded as good or excellent in 73.8%. In this cohort of OLT candidates without known CAD, 9% had normal coronary arteries, 58% had mild CAD and 34% had moderate to severe CAD. Plaque severity and burden scores were high.

CONCLUSION

The prevalence of asymptomatic CAD is high in OLT candidates. Coronary MDCTA is feasible in OLT candidates and appears to be a useful technique to diagnose occult CAD in this patient population.

Lipid-lowering therapy with statins for the primary and secondary prevention of cardiovascular disease

Cardiovascular disease (CVD) still ranks as the top cause of mortality worldwide. Lipid-modifying therapy has revolutionized the treatment of the disease and is partly responsible for the recent decline in deaths due to CVD. Treatment strategies have evolved since the introduction of the earlier lipid-lowering agents (fibrates, niacin, bile acid resins) to the advent of statins, which have become the standard drugs in cholesterol therapy. The strategy of using high-intensity statin therapy as the initial treatment approach in high-risk individuals, rather than focusing on specific cholesterol levels alone, remains a subject of debate.

Prognostic value of coronary computed tomographic angiography in comparison with calcium scoring and clinical risk scores

BACKGROUND

Several studies have demonstrated a high accuracy of coronary computed tomography angiography (CCTA) for detection of obstructive coronary artery disease (CAD), whereas some studies have also shown a good prediction of cardiac events. However, it remains to be proven whether CCTA is better predictive of events than conventional risk scores or calcium scoring. Therefore, we compared CCTA with calcium scoring and clinical risk scores for the ability to predict cardiac events.

METHODS AND RESULTS

Patients (n=2223) with suspected CAD undergoing CCTA were followed up for a median of 28 months. The end point was the occurrence of cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and coronary revascularization later than 90 days after CCTA). Patients with obstructive CAD had a significantly higher event rate (2.9% per year; 95% confidence interval, 2.1 to 4.0) than those without obstructive CAD, having an event rate 0.3% per year (95% confidence interval, 0.1 to 0.5; hazard ratio, 13.5; 95% confidence interval, 6.7 to 27.2; P<0.001). CCTA had significant incremental predictive value when compared with calcium scoring, both with scores assessing the degree of stenosis (P<0.001) and with scores assessing the number of diseased coronary segments (P=0.027).

CONCLUSIONS

In patients with suspected CAD, CCTA not only detects coronary stenosis but also improves prediction of cardiac events over and above conventional risk scores and calcium scoring. This may result in a reclassification of cardiovascular risk in a substantial proportion of patients.

Prognostic value of coronary computed tomographic angiography in asymptomatic patients

To assess the value of coronary computed tomographic angiography (CCTA) in the prediction of cardiac events in asymptomatic patients, 451 consecutive asymptomatic patients who underwent CCTA from December 2003 to November 2007 were retrospectively analyzed. The primary end point of the study was the occurrence of cardiac events, defined as cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and late revascularization (>90 days after CCTA) during a median follow-up period of 27.5 months. Secondary end points were the prevalence of nonobstructive coronary lesions and the number of patients reclassified regarding their cardiovascular risk. Two hundred twenty-nine patients (54%) had nonobstructive coronary lesions, and 107 patients (24%) obstructive coronary artery disease. During follow-up, there were 2 cases of unstable angina and 8 revascularizations for stable angina. Patients with obstructive coronary artery disease had a significantly higher event rate than those without obstructive CAD (risk ratio 13.9, 95% confidence interval 4.0 to 48.0). In 217 patients (48%), the clinically assessed cardiovascular risk could be reclassified by CCTA from intermediate or high to low risk. In conclusion, although the event rate was low in asymptomatic patients, CCTA could reliably predict further cardiac events and could reclassify 2/3 of patients regarding their cardiovascular risk.

Optical molecular imaging in atherosclerosis

Current imaging techniques focus on evaluating the anatomical structure of blood vessel wall and atherosclerotic plaque. These techniques fail to evaluate the biological processes which take place in the vessel wall and inside the plaque. Novel imaging techniques like optical imaging can evaluate the biological and cellular processes inside the plaque and provide information which can be vital for better patient risk stratification. This review highlights the various optical imaging techniques and their application in assessing biological processes in atherosclerosis.

Prognostic value of coronary computed tomographic angiography for prediction of cardiac events in patients with suspected coronary artery disease

OBJECTIVES

We assessed the rate of cardiac events after detection or exclusion of obstructive coronary artery disease (CAD) by coronary computed tomography angiography (CCTA).

BACKGROUND

Several studies have demonstrated a high diagnostic accuracy of CCTA for detection of obstructive CAD compared with invasive angiography, but data regarding the clinical prognostic value of CCTA are limited.

METHODS

In all, 1,256 consecutive patients with suspected CAD undergoing 64-slice CCTA in our institution between October 2004 and September 2006 were observed prospectively for the occurrence of severe cardiac events (cardiac death, myocardial infarction, or unstable angina requiring hospitalization: primary study end point) and all cardiac events (additionally including revascularization >90 days after CCTA). The observed rate of all cardiac events was compared with the event rate predicted by the Framingham risk score. Obstructive CAD was defined as > or = 50% diameter stenosis in any coronary artery.

RESULTS

During a median follow-up of 18 months (interquartile range 14 to 25 months), the overall rates of severe and all cardiac events were 0.6% and 1.8%, respectively. In 802 patients without obstructive CAD, there were 4 cardiac events, of which 1 was severe, whereas in 348 patients with obstructive CAD, there were 17 cardiac events, of which 5 were severe. The difference between the 2 groups was highly significant both for severe events (odds ratio: 17.3, 95% confidence interval: 3.6 to 82.5) and for all cardiac events (odds ratio: 16.1, 95% confidence interval: 7.2 to 36.0; both p < 0.001). The rate of all cardiac events in patients without obstructive CAD was significantly lower than predicted by the Framingham risk score (p = 0.01).

CONCLUSIONS

In patients with suspected CAD, CCTA has a significant prognostic impact on the prediction of cardiac events for the subsequent 18 months. The exclusion of obstructive CAD by CCTA identifies a patient population with an event risk lower than predicted by conventional risk factors.

Detection of the vulnerable coronary atheromatous plaque. Where are we now?

Atherosclerosis is a progressive process with potentially devastating consequences and has been identified as the leading cause of morbidity and mortality, especially in the industrial countries. The underlying mechanisms include endothelial dysfunction, lipid accumulation and enhanced inflammatory involvement resulting in plaque disruption or plaque erosion and subsequent thrombosis. However, it has been made evident, that the majority of rupture prone plaques that produce acute coronary syndromes are not severely stenotic. Conversely, lipid-rich plaques with thin fibrous cap, heavily infiltrated by inflammatory cells have been shown to predispose to rupture and thrombosis, independently of the degree of stenosis. Therefore, given the importance of plaque composition, a continuously growing interest in the development and improvement of diagnostic modalities will promptly and most importantly, accurately detect and characterize the high-risk atheromatous plaque. Use of these techniques may help risk stratification and allow the selection of the most appropriate therapeutic approach.

Optical and multimodality molecular imaging: insights into atherosclerosis

Imaging approaches that visualize molecular targets rather than anatomic structures aim to illuminate vital molecular and cellular aspects of atherosclerosis biology in vivo. Several such molecular imaging strategies stand ready for rapid clinical application. This review describes the growing role of in vivo optical molecular imaging in atherosclerosis and highlights its ability to visualize atheroma inflammation, calcification, and angiogenesis. In addition, we discuss advances in multimodality probes, both in the context of multimodal imaging as well as multifunctional, or "theranostic," nanoparticles. This review highlights particular molecular imaging strategies that possess strong potential for clinical translation.

Comparison of Methods for Magnetic Resonance-Guided [18-F]Fluorodeoxyglucose Positron Emission Tomography in Human Carotid Arteries

Background and Purpose— Inflammation is a major risk factor for atherosclerotic plaque rupture and clinical events. Previous studies have shown that plaque [ 18 F]fluorodeoxyglucose (FDG) uptake correlates with macrophage content. In this study we examined the reproducibility of 3 methods of quantifying plaque FDG uptake in the carotid arteries using positron emission tomography (PET). The correlation between 2 simplified uptake parameters (standardized uptake value [SUV], vessel wall-to-blood ratio [VBR]) and a gold standard technique (influx rate [K i ]) was also determined. We used MRI to correct carotid plaque FDG uptake for partial volume error.

Methods— Seven patients with a recent carotid territory transient ischemic attack underwent imaging twice within 8 days using MR and FDG-PET. MR coregistered to PET was used to delineate regions of interest, and to facilitate partial volume correction (PVC).

Results— SUV was the most reproducible parameter irrespective of whether it was normalized by body surface area (BSA), lean body mass, or weight (intraclass correlation coefficient=0.85, 0.88, and 0.90, respectively). VBR correlated better to K i than SUV ( r =0.58 VBR, r =0.46 SUV BSA ). PVC improved these correlations to r =0.81 VBR and r =0.76 SUV BSA , and only slightly degraded the reproducibility of SUV (intraclass correlation coefficient=0.83–0.85).

Conclusions— MR-guided FDG-PET is a highly reproducible technique in the carotid artery and the excellent anatomic detail provided by MR facilitates PVC. Of the methods examined, SUV BSA PVC appears to represent the best compromise between reproducible and accurate determination of FDG metabolism in carotid artery vessel wall.

Inflammation and plaque vulnerability

Development of a thrombus at the site of an atherosclerotic plaque initiates abrupt arterial occlusion and is the proximate event responsible for the vast majority of acute ischemic syndromes. In nearly 75% of cases thrombus overlies a disrupted or ruptured plaque whereas the remainder of the thrombi overly an intact plaque with superficial endothelial erosion. Over the past several years, it has been recognized that plaque composition rather than plaque size or stenosis severity is important for plaque rupture and subsequent thrombosis. Ruptured plaques, and by inference, plaques prone to rupture, tend to be large in size with associated expansive arterial remodeling, thin fibrous cap with a thick or large necrotic lipid core with immuno-inflammatory cell infiltration in fibrous cap and adventitia and increased plaque neovascularity and intraplaque hemorrhage. The size of the necrotic lipid core and extent and location of plaque inflammation appear to be key factors in determining plaque instability. Inflammation and immune cell activation appears to play a key role in the loss of collagen in the fibrous cap, a prelude to fibrous cap rupture, through release of collagen degrading enzymes. Furthermore, inflammation may also play a key role in the death of collagen synthesizing smooth muscle cells which further contributes to loss of fibrous cap integrity. Inflammation also is likely a key player in the ensuing thrombosis that follows plaque disruption through the elaboration of the pro-coagulant protein, tissue factor. An improved understanding of the pathophysiology of plaque vulnerability and subsequent athero-thrombosis should provide novel insights into improved prevention of athero-thrombotic cardiovascular events.

Low utilisation of cardiovascular risk reducing therapy in patients with acute coronary syndromes and non-obstructive coronary artery disease

BACKGROUND

Between 6-25% of patients undergoing coronary angiography for acute coronary syndrome (ACS) have non-obstructive coronary artery disease (NOCAD).

METHODS

One-hundred and eighty patients presenting with an ACS who were taking part in a risk factor modification study and had undergone coronary angiography were examined. We compared baseline characteristics, medical treatment and 12-month outcome in patients with NOCAD (<50% lumen diameter stenosis at coronary angiography) and obstructive CAD (> or = 50% lumen diameter stenosis at coronary angiography).

RESULTS

There were 29 (16%) patients with NOCAD and 151 (84%) with obstructive CAD (CAD). Patients with NOCAD were significantly younger, more likely to be female, had higher mean total cholesterol and LDL levels, and fewer received cardiac rehabilitation, treatment with statins, aspirin, ACE inhibitors, beta-blockers or clopidogrel. Over the next 12-months, there was no mortality or myocardial infarction in the NOCAD group compared to 2% in the CAD group, but 14% with NOCAD were readmitted for a cardiovascular cause including 2 patients (7%) who underwent percutaneous coronary intervention (PCI).

CONCLUSIONS

Patients presenting with ACS and NOCAD may not have a completely benign prognosis, and preventative strategies and therapies such as statins in this group of patients appear to be under-utilised.