In vivo validation of compensatory enlargement of atherosclerotic coronary arteries

Assessment of the Severity of Left Anterior Descending Coronary Artery Stenoses by Enhanced Transthoracic Doppler Echocardiography: Validation of a Method Based on the Continuity Equation

BACKGROUND

To verify whether the severity of coronary stenosis could be non-invasively assessed by enhanced transthoracic coronary echo Doppler in convergent color Doppler mode (E-Doppler TTE) over a wide range of values (from mild to severe).

METHODS

Color-guided pulsed wave Doppler sampling in the left anterior descending coronary artery (LAD) was performed in 103 diseased LAD segments (corresponding to 94 patients examined) as assessed by quantitative coronary angiography (QCA) or intracoronary ultrasound (IVUS). The E-Doppler TTE examinations consisted of measuring the velocity (vel) at the stenosis site and a reference adjacent segment. Then the continuity equation (C-Eq) was applied to calculate the percent cross-sectional area reduction (%CSA) at the stenosis site. The applied formula was: %CSA = 100 × (1 - [TVIref × 0.5]/TVIs). TVI = the time velocity integral at the stenosis [s] and the reference site [ref], respectively); 0.5 = the correcting factor for a parabolic profile was used only when the % accelerated stenotic flow was >122% (AsF = diastolic peak vel at first site - diastolic peak vel at second site/diastolic peak vel at second site × 100).

RESULTS

E-Doppler TTE feasibility was 100%. Doppler and QCA/IVUS-derived %CSA stenosis showed very good agreement over a large range of values (from mild to severe), with no significant bias; the maximum difference between QCA/IVUS and transthoracic Doppler %CSA was mostly around 20% with a few patients exceeding this limit (limits of agreement = -27.53 to 23.5%). The scattering was slightly larger for the non-significant stenoses. The correlation was strong (r = 0.89, p < 0.001).

CONCLUSION

E-Doppler TTE is a feasible and reliable method for assessing the severity of LAD stenosis by applying the C-Eq.

Measurement of compensatory arterial remodelling over time with serial coronary computed tomography angiography and 3D metrics

AIMS

The magnitude of alterations in which coronary arteries remodel and narrow over time is not well understood. We aimed to examine changes in coronary arterial remodelling and luminal narrowing by three-dimensional (3D) metrics from serial coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

From a multicentre registry of patients with suspected coronary artery disease who underwent clinically indicated serial CCTA (median interscan interval = 3.3 years), we quantitatively measured coronary plaque, vessel, and lumen volumes on both scans. Primary outcome was the per-segment change in coronary vessel and lumen volume from a change in plaque volume, focusing on arterial remodelling. Multivariate generalized estimating equations including statins were calculated comparing associations between groups of baseline percent atheroma volume (PAV) and location within the coronary artery tree. From 1245 patients (mean age 61 ± 9 years, 39% women), a total of 5721 segments were analysed. For each 1.00 mm3 increase in plaque volume, the vessel volume increased by 0.71 mm3 [95% confidence interval (CI) 0.63 to 0.79 mm3, P < 0.001] with a corresponding reduction in lumen volume by 0.29 mm3 (95% CI -0.37 to -0.21 mm3, P < 0.001). Serial 3D arterial remodelling and luminal narrowing was similar in segments with low and high baseline PAV (P ≥ 0.496). No differences were observed between left main and non-left main segments, proximal and distal segments and side branch and non-side branch segments (P ≥ 0.281).

CONCLUSIONS

Over time, atherosclerotic coronary plaque reveals prominent outward arterial remodelling that co-occurs with modest luminal narrowing. These findings provide additional insight into the compensatory mechanisms involved in the progression of coronary atherosclerosis.

Positive Remodeling – a Major Feature of Vulnerability in Patients with Non-Obstructive Coronary Artery Disease

The most common cause of acute coronary syndrome is thrombosis of an atheromatous plaque. Positive remodeling is the compensatory dilatation of the plaque-containing section of the vessel wall. Plaques are most commonly characterized as vulnerable when possessing some of the following features: fibrous cap thickness <65 µm, large necrotic lipid core, high degrees of inflammatory infiltrates, positive remodeling, intraplaque hemorrhage, or neoangio-genesis. The presence of these plaque features is associated with high cardiovascular risk. In the initial stage of vasculopathy, due to positive remodeling, lumen reduction is not typical; it only develops in the advanced phase of the disease, due to which, based on a lumenogram, the vascular system may appear intact. Therefore, coronary angiography can easily miss the diagnosis or underestimate its extent, since it does not inform us of the composition of the arterial wall, because the contrast agent is just filling the vessel lumen. Coronary CT angiography may fill this diagnostic gap, since changes of the vessel wall can directly be visualized. To increase diagnostic accuracy, invasive coronary angiography can be completed by intravascular ultrasound and optical coherence tomography.

Assessment of New Coronary Features on Quantitative Coronary Angiographic Images With Innovative Unsupervised Artificial Adaptive Systems: A Proof-of-Concept Study

Background and Purpose: The Active Connection Matrixes (ACMs) are unsupervised artificial adaptive systems able to extract from digital images features of interest (edges, tissue differentiation, etc.) unnoticeable with conventional systems. In this proof-of-concept study, we assessed the potentiality of ACMs to increase measurement precision of morphological structures (e.g., stenosis and lumen diameter) and to grasp morphological features (arterial walls) from quantitative coronary angiography (QCA), unnoticeable on the original images. Methods: Archive images of QCA and intravascular ultrasound (IVUS) of 10 patients (8 men, age 69.1 ± 9.7 years) who underwent both procedures for clinical reasons were retrospectively analyzed. Arterial features derived from "IVUS images," "conventional QCA images," and "ACM-reprocessed QCA images" were measured in 21 coronary segments. Portions of 1-mm length (263 for lumen and 526 for arterial walls) were head-to-head compared to assess quali-quantitative between-methods agreement. Results: When stenosis was calculated on "ACM-reprocessed QCA images," the bias vs. IVUS (gold standard) did not improve, but the correlation coefficient of the QCA-IVUS relationship increased from 0.47 to 0.83. When IVUS-derived lumen diameters were compared with diameters obtained on ACM-reprocessed QCA images, the bias (-0.25 mm) was significantly smaller (p < 0.01) than that observed with original QCA images (0.58 mm). ACMs were also able to extract arterial wall features from QCA. The bias between the measures of arterial walls obtained with IVUS and ACMs, although significant (p < 0.01), was small [0.09 mm, 95% CI (0.03, 0.14)] and the correlation was fairly good (r = 0.63; p < 0.0001). Conclusions: This study provides proof of concept that ACMs increase the measurement precision of coronary lumen diameter and allow extracting from QCA images hidden features that mirror well the arterial walls derived by IVUS.

Expansive carotid artery remodeling: possible marker of vulnerable plaque

OBJECTIVE

Accumulated findings in the pathophysiology of atherosclerosis have demonstrated that not only luminal narrowing but also plaque characteristics influence the risk of future ischemic events. The morphology of the carotid artery (CA) changes in response to atherosclerotic development by expansive remodeling (ER), the clinical significance of which remains unclear. This study aimed to define associations between ER and local risk factors, including CA geometry and traditional systemic risk factors for ischemic events, to determine whether ER could serve as a clinical marker of carotid vulnerable plaque.

METHODS

The authors retrospectively analyzed 66 patients with CA stenosis who were scheduled to undergo carotid endarterectomy or CA stenting. They calculated ER ratios in the internal CA (ICA) from long-axis MR images and as the maximal distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA/the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis. Relative overall signal intensity (roSI) was calculated to assess intraplaque hemorrhage and defined as the signal intensity of plaque on an axial T1-weighted image with maximal stenosis relative to that of the adjacent sternocleidomastoid muscle. The authors evaluated CA geometry by calculating the angles between the common CA (CCA) and ICA, and between the CCA and external CA (ECA) using digital subtraction angiography. The ER ratios, age, sex, percentage of stenosis, roSI, hypertension, hyperlipidemia, low-density lipoprotein, statin medication, diabetes, smoking habit, and ischemic heart disease were compared between 33 symptomatic and 33 asymptomatic patients. The authors also compared symptomatic status, age, sex, percentage of stenosis, ICA angle, ECA angle, roSI, and other traditional atherosclerotic risk factors between groups with extensive and slight ER.

RESULTS

The ER ratio was significantly greater in symptomatic than in asymptomatic patients (1.91 ± 0.46 vs 1.68 ± 0.40, p < 0.05). The ICA angle was significantly larger in the group with extensive ER than in those with slight ER (33.9° ± 20.2° vs 21.7° ± 13.8°, p < 0.01). The roSI, ECA angle, percentage stenosis, or any other traditional vascular risk factors were not associated with ER.

CONCLUSIONS

Carotid ER might be an independent indicator of carotid vulnerable plaque, which should be validated in a longitudinal study of patients with carotid atherosclerosis, including those with nonstenotic to moderate stenosis.

Calcification in Atherosclerotic Plaque Vulnerability: Friend or Foe?

Calcification is a clinical marker of atherosclerosis. This review focuses on recent findings on the association between calcification and plaque vulnerability. Calcified plaques have traditionally been regarded as stable atheromas, those causing stenosis may be more stable than non-calcified plaques. With the advances in intravascular imaging technology, the detection of the calcification and its surrounding plaque components have evolved. Microcalcifications and spotty calcifications represent an active stage of vascular calcification correlated with inflammation, whereas the degree of plaque calcification is strongly inversely related to macrophage infiltration. Asymptomatic patients have a higher content of plaque calcification than that in symptomatic patients. The effect of calcification might be biphasic. Plaque rupture has been shown to correlate positively with the number of spotty calcifications, and inversely with the number of large calcifications. There may be certain stages of calcium deposition that may be more atherogenic. Moreover, superficial calcifications are independently associated with plaque rupture and intraplaque hemorrhage, which may be due to the concentrated and asymmetrical distribution of biological stress in plaques. Conclusively, calcification of differential amounts, sizes, shapes, and positions may play differential roles in plaque homeostasis. The surrounding environments around the calcification within plaques also have impacts on plaque homeostasis. The interactive effects of these important factors of calcifications and plaques still await further study.

Molecular and Nonmolecular Magnetic Resonance Coronary and Carotid Imaging

Atherosclerosis is the leading cause of cardiovascular morbidity and mortality. Over the past 2 decades, increasing research attention is converging on the early detection and monitoring of atherosclerotic plaque. Among several invasive and noninvasive imaging modalities, magnetic resonance imaging (MRI) is emerging as a promising option. Advantages include its versatility, excellent soft tissue contrast for plaque characterization and lack of ionizing radiation. In this review, we will explore the recent advances in multicontrast and multiparametric imaging sequences that are bringing the aspiration of simultaneous arterial lumen, vessel wall, and plaque characterization closer to clinical feasibility. We also discuss the latest advances in molecular magnetic resonance and multimodal atherosclerosis imaging.

Long-Term Evolutionary Change in the Lumen of Intracranial Atherosclerotic Stenosis Following Angioplasty and Stenting

BACKGROUND

Angioplasty and stenting is a recognized treatment option for patients with intracranial atherosclerosis.

OBJECTIVE

To evaluate the long-term evolutionary luminal changes of intracranial atherosclerosis after angioplasty and stenting.

METHODS

This was a retrospective study with patient consent. Eighty-two patients presenting with acute and minor cerebral ischemia due to stenosis ≥70%, who had received medical therapy with or without stenting (Wingspan), were invited. Luminal imaging was provided using 3-dimensional rotational angiography (3-DRA) at baseline and 12 mo, and cone-beam computed tomography angiography with intravenous contrast (CBCT) was provided at follow-up (median 82.4 mo [interquartile range 61.9-96.9 mo]).

RESULTS

Thirty-six patients in the stenting group and 26 patients in the medical group were recruited and completed the study. There was no statistically significant difference in demographics between the 2 patient groups. The luminal gain at 12 or 80 mo as compared to baseline in the stenting group was significantly greater than that in the medical group (12 mo: median gain 30% vs 7.2%, P < .001; 80 mo: median gain 42.9% vs 7.2%, P < .0001). Luminal loss or unchanged lumen was correlated with recurrent ischemic event. The differences in the stenosis degree assessment between CBCT and 3-DRA in the same 10 patients with or without stenting were 1.2 ± 0.6% or 0.2 ± 0.06%, respectively. There was a correlation between recurrent ischemic events and luminal loss.

CONCLUSION

Arterial lumen after angioplasty and stenting can probably be well maintained and delayed luminal gain does occur, long-term luminal loss is associated with recurrent ischemic events, CBCT might be useful as a less-invasive means for long-term assessment.

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.

The use of echocardiography for the non-invasive evaluation of coronary artery disease

In the Western world, there are now millions of patients who undergo clinical procedures that evaluate coronary artery status each year. Methods span from direct imaging using angiography, computerized tomography, to nuclear magnetic imaging as well as to functional studies, such as positron emission tomography. These techniques have provided significant information to physicians, but there is still need for an improved accessibility. Angiographic methods are expensive and expose the patient to significant amounts of radiation, undesirable in younger patients. Among the novel technologies for coronary diagnostics, transthoracic echocardiography (TTE) of coronary arteries has provided an important alternative, particularly in everyday practice. Diagnostic arterial TTE can allow determination of the coronary wall lumen in at least three major coronary segments (left main [LM], left arterial descending [LAD] and right coronary artery [RCA]). Coronary wall thickness using the LAD has been preliminarily shown to be related to the risk of coronary events. Since it is well ascertained that coronary lesions found in any location indicate that at least 80% of the coronary tree is affected, this is very important clinical information. Evaluation of coronary status by TTE is a novel technology providing important information in ischemic syndromes, in cases of coronary malformations and other coronary diseases. KEY MESSAGES Coronary evaluation can be carried out by a variety of both invasive and non-invasive methods, many requiring radiation exposure or patient immobility. Transthoracic echocardiography (TTE) of the coronaries can, in particular, evaluate the coronary wall thickness, and this may be directly related to the coronary disease risk. TTE is a useful method for the monitoring of coronary flow reserve and can allow the detection of coronary malformations.

Relation between baseline plaque features and subsequent coronary artery remodeling determined by optical coherence tomography and intravascular ultrasound

Atherosclerosis often leads to myocardial infarction and stroke. We examined the influence of baseline plaque characteristics on subsequent vascular remodeling in response to changes in plaque size. Using optical coherence tomography (OCT) and intravascular ultrasound (IVUS), we examined 213 plaques from 138 patients with acute coronary syndrome at baseline and repeated IVUS at the 12-month follow-up. The change in external elastic membrane (EEM) area for each 1 mm2 change in plaque area (i.e., the slope of the regression line) was calculated as a measure of vascular remodeling capacity. In plaques with static positive remodeling, the slope was smaller than in plaques without static positive remodeling. In addition, the slope of the regression line for lesions with a large plaque burden was much smaller than that for lesions with a small plaque burden. Multivariate linear regression analysis showed that diabetes, calcification and static positive remodeling were inversely and independently associated with the level of change in EEM area/change in plaque area. Lesions with a large plaque burden, calcifications or static positive remodeling had less remodeling capacity, and calcification and static positive remodeling were independent predictors of reduced subsequent remodeling. Therefore, calcifications and static positive remodeling could be used as morphological biomarkers to predict decreased subsequent arterial remodeling.

Characterization of intracranial atherosclerotic stenosis using high-resolution MRI study--rationale and design

BACKGROUND

Intracranial atherosclerosis is a leading cause of stroke, but little is known about the composition of the intracranial atherosclerotic lesion and how intracranial plaque morphology is related to the risk of stroke. High-resolution magnetic resonance imaging (HR MRI) has been used in patients with extracranial carotid atherosclerosis as an in vivo tool to identify, with high-interrater agreement, histologically defined plaque components (i.e., intraplaque hemorrhage, fibrous cap, and lipid core), which have been shown to be predictors of recurrent stroke. With careful imaging the components of atherosclerotic plaque can be visualized in the intracranial arteries using HR MRI, but there are no reports of reproducibility or interrater reliability.

METHODS/STUDY DESIGN

The Characterization of intracranial atherosclerotic stenosis using high-resolution MRI (CHIASM) study is a single-center NIH-funded prospective observational study, to (1) demonstrate high -interrater agreement for identifying intracranial plaque components on HR MRI, (2) determine the frequency of these components in symptomatic versus asymptomatic plaques, and (3) estimate the 1-year rate of stroke in the territory of high-risk plaque components. CHIASM will recruit 90 patients with 50-99% intracranial atherosclerosis to undergo HRMRI of the intracranial artery plaque at enrollment and 1-year follow-up. Both symptomatic and asymptomatic subjects will be recruited.

CONCLUSION

Determination of good interrater reliability is an important first step in the development of HR MRI as a tool to predict risk in patients with intracranial atherosclerosis. This study will inform the design of future multicenter studies to determine the prevalence and prognosis of intracranial atherosclerotic plaque components. Such studies could lead to new understanding of the pathophysiological mechanisms of cerebral ischemia in patients with atherosclerotic intracranial stenosis, improvements in risk stratification, and potentially to new treatments of this common and serious disease.

Intravascular Ultrasonic Imaging of Coronary Arterial Remodeling in Heart Transplant Recipients

The purpose of this study was to evaluate long-term changes of transplant coronary arteries, including vessel, plaque, and lumen areas. There are limited long-term data on vessel remodeling after heart transplantation. We analyzed serial intravascular ultrasound images of the left anterior descending coronary artery (LAD) in 54 heart transplantation recipients. Nine patients (16.7%) had a history of rejection. Proximal left anterior descending artery segments were matched among time points, a ≥20-mm long segment was analyzed every 1 mm, and results were normalized for analysis length and reported as mm(3)/mm. During follow-up, vessel area decreased (-0.48 ± 1.3 mm(3)/mm/year), and plaque area did not change (-0.01 ± 0.47 mm(3)/mm/year). As a result, lumen area decreased (-0.52 ± 1.34 mm(3)/mm/year). The change in mean lumen area was well correlated to the change in mean vessel area (r = 0.94, p <0.01) but not to the change in mean plaque area (r = -0.27, p = 0.05). In conclusion, lumen loss occurred during long-term follow-up of patients who underwent heart transplantation, primarily secondary to negative remodeling (decrease in vessel dimensions).

The association between expansive arterial remodeling detected by high-resolution MRI in carotid artery stenosis and clinical presentation

OBJECT

The purpose of the present study was to investigate the association between carotid artery (CA) expansive remodeling (ER) and symptoms of cerebral ischemia.

METHODS

One hundred twenty-two consecutive CAs scheduled for CA endarterectomy (CEA) or CA stent placement (CAS) were retrospectively studied. After excluding 22 CAs (2 were contraindicated for MRI, 8 had near-occlusion, 6 had poor image quality, and 6 had restenosis after CEA or CAS), there were 100 CAs (100 patients) included in the final analysis. The study included 50 symptomatic patients (mean age 73.6 ± 8.9 years, 6 women, mean stenosis 68.5% ± 21.3%) and 50 asymptomatic patients (mean age 72.0 ± 5.9 years, 5 women, mean stenosis 79.4% ± 8.85%). Expansive remodeling was defined as enlargement of the internal carotid artery (ICA) with outward plaque growth. The ER ratio was calculated by dividing the maximum distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA by the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis using long-axis, high-resolution MRI.

RESULTS

The ER ratio of the atherosclerotic CA was significantly greater than that of normal physiological expansion (carotid bulb; p < 0.01). The ER ratio of symptomatic CA stenosis (median 1.94, interquartile range [IQR] 1.58–2.23) was significantly greater than that of asymptomatic CA stenosis (median 1.52, IQR 1.34–1.81; p = 0.0001). When the cutoff value of the ER ratio was set to 1.88, the sensitivity and specificity to detect symptoms were 0.6 and 0.78, respectively. The ER ratio of symptomatic patients was consistently high regardless of the degree of stenosis.

CONCLUSIONS

There was a significant correlation between ER ratio and ischemic symptoms. The ER ratio might be a potential indicator of vulnerable plaque, which requires further validation by prospective observational study of asymptomatic patients.

Compensatory Enlargement of Ossabaw Miniature Swine Coronary Arteries in Diffuse Atherosclerosis

Studies in human and non-human primates have confirmed the compensatory enlargement or positive remodeling (Glagov phenomenon) of coronary vessels in the presence of focal stenosis. To our knowledge, this is the first study to document arterial enlargement in a metabolic syndrome animal model with diffuse coronary artery disease (DCAD) in the absence of severe focal stenosis. Two different groups of Ossabaw miniature pigs were fed a high fat atherogenic diet for 4 months (Group I) and 12 months (Group II), respectively. Group I (6 pigs) underwent contrast enhanced computed tomographic angiography (CCTA) and intravascular ultrasound (IVUS) at baseline and after 4 months of high fat diet, whereas Group II (7 pigs) underwent only IVUS at 12 months of high fat diet. IVUS measurements of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries in Group I showed an average increase in their lumen cross-sectional areas (CSA) of 25.8%, 11.4%, and 43.4%, respectively, as compared to baseline. The lumen CSA values of LAD in Group II were found to be between the baseline and 4 month values in Group I. IVUS and CCTA measurements showed a similar trend and positive correlation. Fractional flow reserve (FFR) was 0.91 ± 0.07 at baseline and 0.93 ± 0.05 at 4 months with only 2.2%, 1.6% and 1% stenosis in the LAD, LCX and RCA, respectively. The relation between percent stenosis and lumen CSA shows a classical Glagov phenomenon in this animal model of DCAD.

Clinical study of the hypothesis of endogenous collateral wind on acute coronary syndrome: a review

BACKGROUND

Acute Coronary Syndrome (ACS), is a serious threat to people's health, and life, and in recent years, the incidence has increased yearly. This study was to propose the hypothesis of "endogenous collateral wind" based on the patho-mechanism of thrombogenesis complicated by ruptured plaque on ACS, and the theory of traditional Chinese medicine.

MATERIALS AND METHODS

Through successful coronary angiography (CAG), and intravascular ultrasound (IVUS), patients with coronary artery disease were made the differential diagnosis such as blood stasis, blood stasis due to phlegm obstruction, and endogenous collateral wind. The levels of plasma inflammatory marker were measured to study on the characteristics of "endogenous collateral wind". Luo heng dripping pills with promoting blood circulation to expel wind-evil, and remove wetness were made based on the hypothesis of "endogenous collateral wind" on ACS. Patients with unstable angina were randomly divided into 3, groups based on therapeutic methods: conventional therapy group, Luo Heng dripping pills group and Tongxinluo caps. Differences among groups were compared.

RESULTS

There were great changes in number and degree of coronary arteriostenosis confirmed by CAG, the types of ACC/AHA lesion and Levin lesion confirmed by CAG, remodeling index, positive or negative remodeling percentage measured by IVUS, the plasma levels of plasma inflammatory marker measured by ELLSA in the patients with endogenous collateral wind, compared with patients with blood stasis and blood stasis due to phlegm obstruction. The total effective rate of improved angina in Luo Heng dripping pills group was significantly higher than those in other two groups. The levels of plasma inflammatory marker were significantly lower in Luo Heng dripping pills group.

CONCLUSION

There were some pathological basis which were found about the hypothesis of "endogenous collateral wind" on acute coronary syndrome. It provided evidences for patients with coronary artery disease treated by medicines with expelling evil-wind, and removing wetness.

TGFB1 genetic polymorphisms and coronary heart disease risk: a meta-analysis

BACKGROUND

Genetic variations in TGFB1 gene have been studied in relation to coronary heart disease (CHD) risk, but the results were inconsistent.

METHODS

We performed a systematic review of published studies on the potential role of TGFB1 genetic variation in CHD risk. Articles that reported the association of TGFB1 genetic variants with CHD as primary outcome were searched via Medline and HuGE Navigator through July 2011. The reference lists from included articles were also reviewed.

RESULTS

Data were available from 4 studies involving 1777 cases and 7172 controls for rs1800468, 7 studies involving 5935 cases and 10677 controls for rs1800469, 7 studies involving 6634 cases and 9620 controls for rs1982073, 5 studies involving 5452 cases and 9999 controls for rs1800471, and 4 studies involving 5143 cases and 4229 controls for rs1800472. The pooled odds ratios (ORs) for CHD among minor T allele carriers of rs1800469, minor C allele carriers of rs1982073, and minor C allele carriers of rs1800471 versus homozygous major allele carriers was 1.14 (95% confidence interval [CI]: 1.05-1.24), 1.18 (95% CI: 1.04-1.35), and 1.16 (95% CI: 1.02-1.32), respectively. No substantial heterogeneity for ORs was detected among the included Caucasian populations for all SNPs. However, for rs1800471, the statistical significance disappeared after adjusting for potential publication bias. No significant association was found between rs1800468 and rs1800472 variants and CHD risk.

CONCLUSION

Minor allele carriers of two genetic variants (rs1800469 and rs1982073) in TGFB1 have a 15% increased risk of CHD.

Correlation between high density lipoprotein-cholesterol and remodeling index in patients with coronary artery disease: IDEAS (IVUS diagnostic evaluation of atherosclerosis in Singapore)-HDL study

Serum level of high density lipoprotein (HDL)-cholesterol is associated with risk of coronary artery disease. We correlated the serum level of cholesterol with coronary artery remodeling index of patients with coronary artery disease. A total of 120 patients with de novo lesions located in native coronary artery were studied. Remodeling index was based on intravascular ultrasound (IVUS) interrogation of the lesions using the static approach, and was defined as external elastic membrane (EEM) area at lesion/average EEM area at proximal and distal reference segments. The average remodeling index was 0.9 (SD: 0.2). The remodeling index was not associated with any of the demographic and coronary risk factors. Stable angina was associated with a low remodeling index. Remodeling index correlated with white blood cell count and HDL-cholesterol, but not with total cholesterol, LDL-cholesterol and triglyceride. In the multiple linear regression analysis, HDL-cholesterol and procedure indication were the only 2 significant predictors of remodeling index. An increase of 1 mg/dL of HDL-cholesterol resulted in a decrease of 0.003 (95% CI: 0.0001, 0.007; P = 0.046) in remodeling index, after adjusting for procedural indications. When stratified according to diabetic status, the negative correlation persisted in non-diabetic (P = 0.023), but not in diabetic, patients (P = 0.707). We found a negative correlation between HDL-cholesterol level and remodeling index. Diabetic status may have an influence on the observed relationship.

Phase-sensitive black-blood coronary vessel wall imaging

Black-blood MR coronary vessel wall imaging may become a powerful tool for the quantitative and noninvasive assessment of atherosclerosis and positive arterial remodeling. Although dual-inversion recovery is currently the gold standard, optimal lumen-to-vessel wall contrast is sometimes difficult to obtain, and the time window available for imaging is limited due to competing requirements between blood signal nulling time and period of minimal myocardial motion. Further, atherosclerosis is a spatially heterogeneous disease, and imaging at multiple anatomic levels of the coronary circulation is mandatory. However, this requirement of enhanced volumetric coverage comes at the expense of scanning time. Phase-sensitive inversion recovery has shown to be very valuable for enhancing tissue-tissue contrast and for making inversion recovery imaging less sensitive to tissue signal nulling time. This work enables multislice black-blood coronary vessel wall imaging in a single breath hold by extending phase-sensitive inversion recovery to phase-sensitive dual-inversion recovery, by combining it with spiral imaging and yet relaxing constraints related to blood signal nulling time and period of minimal myocardial motion.

Chemotactic Preferences and Strain Variation in the Response of Phytophthora sojae Zoospores to Host Isoflavones

The zoospores of Phytophthora sojae are chemotactically attracted to the isoflavones genistein and daidzein that are released by soybean roots. In this study we have examined the response of P. sojae zoospores to a wide range of compounds having some structural similarity to genistein and daidzein, including isoflavones, flavones, chalcones, stilbenes, benzoins, benzoates, benzophenones, acetophenones, and coumarins. Of 59 compounds examined, 43 elicited some response. A comparison of the chemotactic responses elicited by the various compounds revealed a primary role for the phenolic 4(prm1)- and 7-hydroxyl groups on the isoflavone structure. A few compounds acted as repellents, notably methylated flavones with a hydrophobic B ring. The chemotactic response to many of the analogs was markedly different among different strains of P. sojae.

Positive remodeling of the coronary arteries detected by magnetic resonance imaging in an asymptomatic population: MESA (Multi-Ethnic Study of Atherosclerosis)

OBJECTIVES

The purpose of this study was to assess coronary arterial remodeling as a marker of subclinical atherosclerosis using coronary wall magnetic resonance imaging (MRI) in an asymptomatic population-based cohort.

BACKGROUND

In early atherosclerosis, compensatory enlargement of both the outer wall of the vessel as well as the lumen, termed compensatory enlargement or positive remodeling, occurs before luminal narrowing.

METHODS

One hundred seventy-nine participants in the MESA (Multi-Ethnic Study of Atherosclerosis) trial were evaluated using black-blood coronary wall MRI. Coronary cross-sectional area (vessel size), lumen area, and mean wall thickness of the proximal coronary arteries were measured.

RESULTS

Men had a greater vessel size, lumen area, and mean wall thickness than women (38.3 +/- 11.3 mm2 vs. 32.6 +/- 9.4 mm2, 6.7 +/- 3.2 mm2 vs. 5.3 +/- 2.4 mm2, and 2.0 +/- 0.3 mm vs. 1.9 +/- 0.3 mm, respectively, p < 0.05). No significant coronary artery narrowing was present by magnetic resonance angiography. Overall, coronary vessel size increased 25.9 mm2 per millimeter increase in coronary wall thickness, whereas lumen area increased only slightly at 3.1 mm2 for every millimeter increase in wall thickness (difference in slopes, p < 0.0001). Adjusting for age and sex, participants with an Agatston score >0 were more likely to have wall thickness >2.0 mm (odds ratio: 2.0, 95% confidence interval: 1.01 to 3.84).

CONCLUSIONS

Coronary wall MRI detected positive arterial remodeling in asymptomatic men and women with subclinical atherosclerosis.

Effort angina in a patient with advanced coronary artery disease. Role played by coronary angiography, Ivus and cardiac CT: case report

Coronary angiography is considered to be the gold standard technique for assessing the severity of obstructive luminal narrowing; however, in a few circumstances it may be misleading. In these cases, cardiac computed tomography (CT) and intravascular ultrasound (IVUS) may help to give a correct interpretation.

In this report, we describe the case of a 62-year-old man whose effort angina was first evaluated with coronary angiography, but whose severe stenosis of the right coronary artery was only observed on cardiac CT and IVUS. This additional diagnosis promptly resulted in a therapeutic approach with percutaneous transluminal coronary angioplasty (PTCA).

Changes in left anterior descending coronary artery wall thickness detected by high resolution transthoracic echocardiography

Recently, it has been demonstrated that high-resolution transthoracic echocardiography (HRTTE) is able to detect differences in the wall thickness of the left anterior descending coronary artery (LAD) between patients with coronary artery disease (CAD) and normal volunteers. The aim of this study was to further validate this technique. One hundred ten volunteers, 58 patients with angiographically proved CAD and 52 control subjects, underwent assessments of their LADs using HRTTE. Anterior and posterior wall thicknesses differed between subjects in the CAD group and controls (1.9 +/- 0.6 vs 1.2 +/- 0.3 mm, p <0.001, and 1.8 +/- 0.5 vs 1.2 +/- 0.3 mm, p <0.001, respectively). External LAD diameter was also greater in subjects in the CAD group compared with controls (5.2 +/- 1.9 vs 4.4 +/- 0.9 mm, respectively, p = 0.01). However, there was no difference in luminal diameter between subjects in the CAD group and the controls (1.9 +/- 0.9 vs 2.1 +/- 0.8 mm, respectively, p = 0.3). In conclusion, HRTTE demonstrated that LAD wall thicknesses and external diameters in patients with CAD were significantly larger than in normal volunteers. Luminal diameter, however, was maintained in the 2 groups, indicating that subjects in the CAD group had undergone positive remodeling at the site measured. This objectively visualized evidence of coronary atherosclerosis with HRTTE would likely be undetected during coronary angiography.

Relationship between degree of remodeling and CT attenuation of plaque in coronary atherosclerotic lesions: An in-vivo analysis by multi-detector computed tomography

Multi-detector CT (MDCT) permits non-invasive visualization of the coronary arteries. Coronary plaque can be visualized, and earlier studies have indicated that the CT attenuation measured in atherosclerotic plaques is influenced by plaque composition. Also, MDCT has been shown to permit assessment of remodeling of coronary atherosclerotic lesions. It is assumed that both lipid-rich plaques and those that display positive remodeling are more prone to rupture and erosion. We thus evaluated the relationship between remodeling and CT attenuation of coronary atherosclerotic plaque by MDCT.

METHODS

Seventy-six patients were investigated by contrast-enhanced 64-slice CT. One-hundred twelve atherosclerotic lesions without substantial calcification and visualized with high image quality were selected. Multiplanar reconstructions orthogonal to the coronary artery were rendered at the lesion and the proximal reference site. Cross-sectional vessel areas were measured to determine the remodeling index (RI: lesion vessel area/reference vessel area) and the CT attenuation of plaque was measured by fitting a region of interest to the plaque area. CT attenuation of plaque was correlated to the presence of positive remodeling index (RI>1.05).

RESULTS

The mean cross-sectional vessel area in the lesion was 0.25+/-0.08 cm(2), the mean reference vessel area was 0.22+/-0.09 cm(2). The mean CT attenuation of the atherosclerotic plaque in the lesions was 71+/-26 HU. CT attenuation of plaque was significantly lower in 72 lesions that displayed positive remodeling (59+/-22 HU) than in 40 lesions with no or with negative remodeling (91+/-20 HU, p<0.001).

CONCLUSIONS

Positive remodeling of coronary atherosclerotic lesions correlates to lower CT attenuation of plaque, which has been demonstrated to be associated with lipid-rich plaque. Both characteristics indicate increased risk for plaque rupture and subsequent events and could thus prove useful when the use of CT imaging for the detection of "vulnerable plaque" is considered.

Alloimmune-mediated vascular remodeling of human coronary artery grafts in immunodeficient mouse recipients is independent of preexisting atherosclerosis

Vascular remodeling rather than intimal thickening is the most important determinant of luminal loss in cardiac graft arteriosclerosis. The impact of donor-transmitted atherosclerotic lesions on alloimmune-mediated arterial injury in an experimental setting is not known. We investigated this issue in a chimeric model of human coronary artery grafts to immunodeficient mouse recipients reconstituted with allogeneic human peripheral blood mononuclear cells. Rejecting grafts demonstrated robust intimal expansion, outward vascular remodeling, and variable lumen loss. There was no significant relationship between preexistent atherosclerosis, gender, and age of the artery donors vs. the degree of alloimmune-induced changes in vessel morphology. Our experimental findings, in a system without the potentially confounding variable of immunosuppressive drugs, are in agreement with the majority of clinical studies that alloimmune-mediated intimal injury and vascular remodeling is independent of preexisting coronary atherosclerosis. Our results support the concept of extending the criteria for organ donors to include modest coronary atherosclerosis.

Relationship Between Coronary Artery Remodeling and Plaque Composition in Culprit Lesions An Intravascular Ultrasound Radiofrequency Analysis

BACKGROUND

The relationship between coronary artery remodeling and culprit plaque composition in vivo has not been fully evaluated by spectral analysis of intravascular ultrasound (IVUS) radiofrequency (RF) data.

METHODS AND RESULTS

IVUS RF analyses were performed for 56 consecutive de novo culprit lesions of 52 patients undergoing percutaneous coronary intervention. Remodeling of culprit lesions was determined using the remodeling index (RI), calculated as the external elastic membrane area of the minimum lumen area (MLA) site divided by that of the proximal reference site. Positive remodeling was defined as RI >1.05, intermediate remodeling as 0.95< or = RI < or =1.05 and negative remodeling as RI <0.95. Among the 56 lesions, positive remodeling was detected in 24, intermediate remodeling in 16, and negative remodeling in 16. At MLA sites, positive remodeling lesions had a larger percentage of the fibrofatty component than negative remodeling lesions (22.5+/-10.3% vs 10.4+/-6.6%, p=0.0001), whereas the latter contained a larger percentage of the dense calcium component than the former (2.8+/-2.9% vs 8.4+/-7.0%, p=0.016).

CONCLUSIONS

Culprit plaques with positive remodeling have a large lipid burden, whereas those with negative remodeling contain a large amount of calcium.

Oxidized low-density lipoprotein and high-density lipoprotein cholesterol modulate coronary arterial remodeling: an intravascular ultrasound study

BACKGROUND

Oxidized low-density lipoprotein (oxLDL) not only plays an important role in plaque formation, but also impairs the endothelium-dependent relaxation. Constrictive remodeling rather than intimal hyperplasia mainly contributes to restenosis after balloon angioplasty. Probucol (powerful antioxidant) reduced restenosis rate by improving constrictive remodeling. Thus, oxLDL may modulate coronary arterial remodeling.

HYPOTHESIS

The study was designed for using intravascular ultrasound to test the hypothesis that arterial constrictive remodeling (CR) was associated with oxLDL in patients with coronary artery disease.

METHODS

Intravascular ultrasound was performed in 36 patients with de novo atherosclerotic coronary. Remodeling was defined and evaluated as follows: remodeling index (RI) = lesion vessel area (VA)/(proximal reference VA + distal reference VA)/2. Constrictive remodeling (CR) was defined as remodeling index (RI) < 0.9. Neutral and expansive remodeling (NER) was defined as RI > or = 0.9. The level of plasma ox-LDL was measured by sandwich ELISA using the monoclonal antibody (DLH3)-recognized oxidatively modified lipoproteins and the antihuman apoprotein B monoclonal antibody.

RESULTS

Neutral and expansive remodeling was found in 24 lesions, and CR in 12 lesions. Remodeling index was significantly lower in the CR group than in the NER group (0.8 +/- 0.1 vs. 1.0 +/- 0.1, p < 0.001). The level of oxLDL in the CR group was significantly higher than that in the NER group (24.0 +/- 12.1 vs. 16.4 +/- 6.2 U/ml, p < 0.05). The level of high-density lipoprotein-cholesterol (HDL-C) in the CR group was significantly lower than that in the NER group (40.5 +/- 4.8 vs. 46.2 +/- 10.6 mg/ml, p < 0.05). There was a statistically significant correlation between the value of HDL-C/ ox-LDL and the RI (r = -0.48, p < 0.005).

CONCLUSIONS

Oxidized LDL and HDL-C were associated with arterial remodeling in de novo atherosclerotic lesions.

Prospective comparison of coronary artery remodeling between acute coronary syndrome and stable angina in single-vessel disease: correlation between C-reactive protein and extent of arterial remodeling

BACKGROUND

Retrospective intravascular ultrasound (IVUS) studies showed that positive remodeling of coronary artery was associated with unstable clinical presentation. However, no prospective IVUS study has been performed to demonstrate such relationship. The relationship between C-reactive protein (CRP) and coronary artery remodeling is unknown.

HYPOTHESIS

Positive remodeling might be related with acute coronary syndrome in the prospective IVUS study. C-reactive protein levels might be associated with coronary artery remodeling.

METHODS

Preintervention IVUS images were prospectively obtained in 93 patients with single-vessel disease (30 for acute coronary syndrome and 63 for stable angina). Serum sample for CRP measurement was collected 24 h prior to coronary intervention. The remodeling index was defined as a ratio of (lesion/average reference) external elastic membrane area. Positive remodeling was defined as a remodeling index > 1.05 and negative remodeling as a remodeling index < 0.95.

RESULTS

The remodeling index was 0.99 +/- 0.13 in acute coronary syndrome versus 0.95 +/- 0.12 in stable angina (p = 0.048). Positive remodeling was associated with acute coronary syndrome (43 vs. 19%), whereas negative remodeling was more frequent in stable angina (49 vs. 33%) (p = 0.047). C-reactive protein levels were significantly higher in acute coronary syndrome than in stable angina (1.4 +/- 2.0 vs. 0.5 +/- 0.6 mg/dl, respectively, p = 0.002). However, there was no significant correlation between CRP levels and remodeling index (r = 0.078, p = 0.475).

CONCLUSIONS

Positive remodeling may be related with acute coronary syndrome in the prospective IVUS analysis. C-reactive protein levels may not predict the extent of arterial remodeling.

Low levels of high-density lipoprotein cholesterol are associated with vascular remodeling in cardiac transplant recipients

BACKGROUND

Early atherosclerosis may be associated with compensatory vessel enlargement, termed positive remodeling. Enlarged brachial artery diameter has been reported in patients with risk factors for atherosclerosis and in individuals with coronary atherosclerosis, indicating that brachial artery enlargement is a marker for the presence of atherosclerotic changes. Cardiac transplant recipients often have abnormal lipid levels, but the effect of specific lipid abnormalities on vascular remodeling in this population has not been evaluated. This study examined the relationship between lipid levels and brachial artery diameter in cardiac transplant recipients.

METHODS

Thirty-five stable cardiac transplant recipients underwent high-resolution brachial artery ultrasound to evaluate resting brachial artery diameter. Levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides were determined and the presence of other cardiac risk factors was assessed.

RESULTS

Brachial artery diameter was larger (4.3 +/- 0.1 mm) in subjects with low levels of HDL-C (< 40 mg/dL, n = 11) compared to subjects with high HDL-C (> or = 40 mg/dL, n = 24), who had a mean brachial artery diameter of 3.7 +/- 0.1 mm (P = .006). Neither high LDL-C (> or = 100 mg/dL) nor high triglycerides (> or = 200 mg/dL) were associated with differences in brachial artery diameter. Multivariate analysis demonstrated that the relationship between low HDL-C and increased brachial artery diameter was independent of body surface area or statin use.

CONCLUSIONS

Low levels of HDL-C are an independent predictor of brachial artery enlargement in stable cardiac transplant recipients. These findings suggest that suboptimal HDL-C levels may be associated with the development of vascular remodeling and atherosclerosis in this population.

Impact of histological plaque characteristics on intravascular ultrasound parameters at culprit lesions in coronary artery disease

Prior intravascular ultrasound (IVUS) studies have demonstrated that a positive remodeling pattern of a culprit lesion is observed more frequently in acute coronary syndrome (ACS) than stable angina (SA). However, the relationship between the plaque morphology detected by IVUS and the histological type of atherosclerotic plaque has not been well defined. This is a prospective study on 37 consecutive patients who underwent directional coronary atherectomy. The 37 patients were divided into 2 groups; 21 patients with SA and 16 with ACS. Vessel and plaque cross sectional area were measured at the culprit lesion and the remodeling index (RI) was calculated by IVUS. The plaque tissue was assessed for the presence of inflammatory cells and lipids, and the presence of each was scored as 0 (absent), 1 (sparse), 2 (dense), or 3 (predominant). The RI of the patients with ACS was higher than that of SA. Inflammatory cells were present to a greater extent in patients with ACS. Inflammatory cells and lipids were significantly correlated with the RI (Inflammatory cell score grade > or = 2 patients; 1.14 +/- 0.13 versus grade 0 patients; 0.87 +/- 0.24, and grade 1 patients; 0.93 +/- 0.17, P < 0.01 and lipid score grade > or = 2 patients; 1.13 +/- 0.17 versus grade 0 patients; 0.85 +/- 0.18, P < 0.001 and grade 1 patients; 0.95 +/- 0.19, P < 0.05). The results clearly indicate that the evaluation of vessel morphology by vascular imaging is an important indicator of plaque instability.

Association of coronary shear stress with endothelial function and vascular remodeling in patients with normal or mildly diseased coronary arteries

BACKGROUND

The relationship between coronary remodeling, shear stress and endothelial function remains unclear.

OBJECTIVE

The present study investigated the effects of mechanical factors on structure and function of epicardial coronary arteries.

METHODS

Patients (group 1: %area stenosis<40%, n=55; or group 2: %area stenosis>or=40%, n=17) with a discrete mildly stenotic lesion (%diameter stenosis<30%) underwent intravascular ultrasound examination of the left anterior descending coronary artery for determination of vessel area, lumen area, plaque area, cross-sectional areas at reference segments, and remodeling index (the ratio of vessel area at the culprit lesion to vessel area at the proximal reference site). Further, vascular reactivity was examined using intracoronary administration of acetylcholine, papaverine, and nitroglycerin.

RESULTS

Vessel area significantly correlated with plaque area in both groups (r=0.65, P<0.0001 and r=0.85, P<0.0001). Group 1 showed significantly greater acetylcholine-induced percentage changes in coronary blood flow (67+/-70 vs. 16+/-75%, P<0.05) and coronary artery diameter (-7+/-18 vs.-32+/-31%, P<0.01) and also significantly smaller coronary wall shear stress (65+/-27 vs. 81+/-32 dynes/cm, P<0.05) than group 2. The percentage increase in coronary blood flow induced by acetylcholine was significantly and positively correlated with remodeling index in group 1 (r=0.64, P<0.0001) but not in group 2 (r=-0.03, P=0.90) and was also significantly and positively correlated with coronary wall shear stress in group 1 (r=0.46, P<0.001) but not in group 2 (r=-0.33, P=0.19).

CONCLUSIONS

Endothelium-dependent vasodilation in the resistance coronary artery correlates with remodeling via increased wall shear stress when target lesions %area stenosis is <40%.

Some thoughts on the vasculopathy of women with ischemic heart disease

Considerable experimental and clinical data indicate that sex has an important influence on cardiovascular physiology and pathology. This report integrates selected literature with new data from the Women's Ischemia Syndrome Evaluation (WISE) on vascular findings in women with ischemic heart disease (IHD) and how these findings differ from those in men. A number of common vascular disease-related conditions are either unique to (e.g., hypertensive disorders of pregnancy, gestational diabetes, peripartum dissection, polycystic ovarian syndrome, etc.) or more frequent (e.g., migraine, coronary spasm, lupus, vasculitis, Raynaud's phenomenon, etc.) in women than men. Post-menopausal women more frequently have many traditional vascular disease risk conditions (e.g., hypertension, diabetes, obesity, inactivity, and so on), and these conditions cluster more frequently in them than men. Considerable evidence supports the notion that, with these requisite conditions, women develop a more severe or somewhat different form of vascular disease than men. Structurally, women's coronary vessels are smaller in size and appear to contain more diffuse atherosclerosis, their aortas are stiffer (fibrosis, remodeling, and so on), and their microvessels appear to be more frequently dysfunctional compared with men. Functionally, women's vessels frequently show impaired vasodilator responses. Limitations of existing data and higher risks in women with acute myocardial infarction, need for revascularization, or heart failure create uncertainty about management. A better understanding of these findings should provide direction for new algorithms to improve management of the vasculopathy underlying IHD in women.

Angiogenesis occurs within the intimal proliferation that characterizes transplant coronary artery vasculopathy

BACKGROUND

Vascular remodeling is central to the development of transplant coronary artery vasculopathy (CAV). For remodeling to occur, a sustained blood and nutrient supply is essential. Here we report on the presence of angiogenesis within the neointima of coronary arteries from cardiac transplant recipients.

METHODS

Coronary arteries from 57 cardiac transplant recipients with CAV were analyzed. Immunocytochemistry with antibodies raised against endothelial cells (CD31, CD34, and vWF), vascular smooth muscle cells (SmA), and activated endothelial cells (MHC 2, P-SEL, E-SEL, and VCAM-1) was performed.

RESULTS

A total of 89% of patients had significant angiogenesis. These vessels appeared as endothelial lined channels and were present in a concentric circumferential pattern within the mid portion of the neointima. These new vessels were present at an interface between an area of intimal hyperplasia and below an area of fibrous regeneration. These 2 distinct zones were present in 64% of the cases, and were clearly demonstrated with an elastic van Gieson (EVG) stain and are distinctly different from that seen in native atherosclerosis. Endothelial activation markers were strongly expressed by the endothelial cells lining new vessels, suggesting that they are functional and may aid in the recruitment of inflammatory cells.

CONCLUSIONS

These data suggest that angiogenesis is present within the intima of CAV lesions and may contribute to the continued obliteration of the vessel lumen. The vessels appear to originate in the intima and may represent the location of the donor endothelium before transplantation. Inhibition of endothelial damage may provide therapeutic options to prevent the progression of CAV.

Compensatory enlargement of human coronary arteries identified by magnetic resonance imaging

The aim of the present study was to evaluate the role of magnetic resonance imaging (MRI) for the non-invasive detection of coronary abnormalities and specifically the remodeling process in patients with coronary artery disease (CAD). MRI was performed in 10 control healthy subjects and 26 patients with angiographically proven CAD of the right coronary (RCA) or left anterior descending (LAD) artery; 23 patients were within two months of acute coronary syndromes, and 3 had stable angina with a positive test for ischemia. Wall thickness (WT), vessel wall area (VWA), total vessel area (TVA), and luminal area (LA) were measured. There were significant increases in WT (mean +/- SEM, RCA: 2.62 +/- 0.75 vs 0.53 +/- 0.15 mm; LAD: 2.21 +/- 0.69 vs 0.62 +/- 0.24 mm) and in VWA (RCA: 30.96 +/- 17.57 vs 2.1 +/- 1.2 mm(2); LAD: 19.53 +/- 7.25 vs 3.6 +/- 2.0 mm(2)) patients compared to controls (P < 0.001 for each variable). TVA values were also greater in patients compared to controls (RCA: 44.56 +/- 21.87 vs 12.3 +/- 4.2 mm(2); LAD: 31.89 +/- 11.31 vs 17.0 +/- 6.2 mm(2); P < 0.001). In contrast, the LA did not differ between patients and controls for RCA or LAD. When the LA was adjusted for vessel size using the LA/TVA ratio, a significant difference was found: 0.33 +/- 0.16 in patients vs 0.82 +/- 0.09 in controls (RCA) and 0.38 +/- 0.13 vs 0.78 +/- 0.06 (LAD) (P < 0.001). As opposed to normal controls, positive remodeling was present in all patients with CAD, as indicated by larger VWA. We conclude that MRI detected vessel wall abnormalities and was an effective tool for the noninvasive evaluation of the atherosclerotic process and coronary vessel wall modifications, including positive remodeling that frequently occurs in patients with acute coronary syndromes.

Cytomegalovirus aggravates intimal hyperplasia in rats by stimulating smooth muscle cell proliferation

Epidemiological and animal studies suggest a role for cytomegalovirus (CMV) in restenosis. Previously, we demonstrated that proliferating smooth muscle cells (SMCs) in the injured arterial wall are particularly susceptible to CMV-induced effects. Therefore, we hypothesised that, depending on the time point of infection after vascular injury, CMV infection may affect cell proliferation either in the media or in the neointima, thereby aggravating the process of restenosis. In the present study, we focused on the individual layers of the arterial wall by evaluating, besides the neointima-to-media ratio, the medial and neointimal area and cellularity in the rat femoral artery. Vascular injury was photochemically induced in rat femoral arteries. Immediately or 14 days thereafter, rats were infected with rat CMV (RCMV) or mock infected. The presence of RCMV in the vascular wall was determined at 3, 5, 14 and 35 days after infection by quantitative real-time PCR. When rats were infected immediately after injury, a significant increase was seen only in the medial but not in the neointimal cross-sectional area. On the other hand, when rats were infected 14 days after the initial injury, a significant increase was only seen in the neointimal area, thereby confirming our hypothesis that RCMV infection primary affects proliferating SMCs. As the mean number of SMCs per microm2 in both cell layers was unchanged despite an increase in cross-sectional area, this implies that RCMV stimulated SMC proliferation. Furthermore, these vascular effects were observed without the virus being abundantly present in the vascular wall, suggesting that inflammatory and immune-mediated responses to RCMV infection are more important in aggravating the response to vascular injury than the virus itself.

Low variation and high reproducibility in plaque volume with intravascular ultrasound

BACKGROUND

Intravascular ultrasound (IVUS) has several advantages compared to angiography when evaluating coronary atherosclerosis in the vessel wall.

METHODS

The accuracy, reproducibility, and short-time spontaneous variation in volume of vessel, plaque and lumen were studied by electrocardiographic-gated three-dimensional (3D) IVUS in 20 male patients with ischaemic heart disease (IHD).

RESULTS

The study lesions were angiographically insignificant, with a length of the analysed segment on 11.4+/-5.9 mm. At baseline the mean minimal lumen diameter was 2.41+/-0.59 mm, minimal lumen area 4.82+/-2.38 mm2, and maximal plaque burden 65.61+/-9.57%. Mean reference diameter was 3.1+/-0.6 mm. No significant changes were observed in volumes of total vessel, lumen or plaque. The coefficient of variation (CV) for two volume measurements at baseline was: vessel 0.8%, plaque 1.3%, and lumen 1.4%. For measurements recorded at baseline and after 12.6+/-1.5 weeks, CV was respectively 3.5%, 3.3% and 6.6%. Reproducibility and interobserver and intraobserver variation showed very high correlations. A linear correlation was present in percent changes over 12.6+/-1.5 weeks between vessel volume and lumen volume (r=0.804; p<0.001) and between percent changes in plaque volume and vessel volume (r=0.581; p=0.007). No correlation was found between changes in plaque volume and lumen volume (r=0.015; p=0.950).

CONCLUSION

ECG-gated 3D IVUS is a highly reproducible method when applied on coronary artery atherosclerosis. CV for lumen volume over 12.6+/-1.5 weeks is twice that of plaque volume indicating the superiority of the 3D IVUS compared to coronary angiography (CAG).

Novel insights into coronary lumen preservation during progression of coronary atherosclerosis in coronary atherosclerosis-prone rabbits

BACKGROUND

In coronary atherosclerosis-prone Watanabe heritable hyperlipidaemic (WHHLCA) rabbits, an animal model for low-density lipoprotein receptor deficiency and spontaneous coronary atherosclerosis, the coronary arteries show compensatory remodelling during the progression of atherosclerosis. Therefore, we analysed coronary remodelling of WHHLCA rabbits quantitatively using a method that eliminates the limitations of previous analytical methods.

METHODS

Arterial remodelling was evaluated in perfusion-fixed coronary arteries of 11 WHHLCA rabbits using both new and previous analyses. With the improved methods removing limitations on quantitative analysis of arterial remodelling, we evaluated how lumen area or arterial size changed with accumulating atherosclerotic plaques compared to before plaque development. The original lumen area before plaque development was calculated using the diameter-length relationship. Wall shear stress change ratio was calculated from changes in arterial size.

RESULTS

Using the old analytical method (and as seen in similar human studies), lumen area increased up to a level of 29% of cross-sectional narrowing. However, with the improved analysis, in cross-sectioning narrowing at levels below 10%, the lumen area modestly decreased, and when the cross-sectional narrowing ranged from 10-68%, the lumen area remained constant, and diminished sharply despite continued remodelling when cross-sectional narrowing reached 70% or above. Arterial remodelling progressed quantitatively to a slight increase in arterial wall shear stress as well as lumen area up to a level of 70% cross-sectional narrowing.

CONCLUSIONS

These findings demonstrate marked influences of arterial tapering and individual variation of arterial size on quantitative analysis of arterial remodelling, and provide the novel insight that coronary compensatory remodelling in atherosclerosis maintains the lumen size up to levels of 70% cross-sectional narrowing in proportion to wall shear stress.

Insights into the pathogenesis of vein graft disease: lessons from intravascular ultrasound

The success of coronary artery bypass grafting (CABG) is limited by poor long-term graft patency. Saphenous vein is used in the vast majority of CABG operations, although 15% are occluded at one year with as many as 50% occluded at 10 years due to progressive graft atherosclerosis. Intravascular ultrasound (IVUS) has greatly increased our understanding of this process. IVUS studies have shown that early wall thickening and adaptive remodeling of vein grafts occurs within the first few weeks post implantation, with these changes stabilising in angiographically normal vein grafts after six months. Early changes predispose to later atherosclerosis with occlusive plaque detectable in vein grafts within the first year. Both expansive and constrictive remodelling is present in diseased vein grafts, where the latter contributes significantly to occlusive disease. These findings correlate closely with experimental and clinicopathological studies and help define the windows for prevention, intervention or plaque stabilisation strategies. IVUS is also the natural tool for evaluating the effectiveness of pharmacological and other treatments that may prevent or slow the progression of vein graft disease in clinical trials.

Intravascular ultrasound assessment of atherosclerosis

Atherosclerosis imaging has taken on increasing importance in the understanding of the natural history of coronary artery disease and the processes leading to luminal narrowing, as well as the assessment of disease burden and therapy efficacy. Intravascular ultrasound (IVUS) has emerged as the new gold standard for atherosclerosis imaging because it provides cross-sectional images of both the arterial wall and lumen with excellent resolution, reveals the diffuse nature of atherosclerosis and the involvement of reference segments, and takes into account vessel wall remodeling. In addition to its clinical indications, IVUS is now widely used as the primary efficacy assessment measure of several antiatherosclerotic approaches in randomized clinical trials. Advantages of IVUS include its ability to reveal antiatherosclerotic effects within a relatively short period of time and with a reasonable sample size, which is in contrast to trials assessing angiographic changes or clinical events. IVUS can also help to determine dose-response relationships in the development of novel pharmacologic agents. IVUS is currently the ideal imaging modality for clinical trials of atherosclerosis progression/regression.

assessment of coronary remodeling in stenotic and nonstenotic coronary atherosclerotic lesions by multidetector spiral computed tomography

OBJECTIVES

This study was designed to investigate whether contrast-enhanced multidetector spiral CT (MDCT) permits assessment of remodeling in coronary atherosclerotic lesions.

BACKGROUND

With sufficient image quality, MDCT permits noninvasive visualization of the coronary arteries, but its ability to assess remodeling has not been evaluated.

METHODS

Out of 102 patients in whom MDCT (16-slice scanner, intravenous contrast, 0.75-mm collimation, 420 ms rotation) was performed before invasive coronary angiography, 44 patients with high-quality MDCT data sets showing atherosclerotic plaque in a proximal coronary artery segment were chosen for evaluation. In multiplanar reconstructions orthogonal to the coronary artery, the cross-sectional vessel area was measured for the respective lesion and for a reference segment proximal to the lesion. The "Remodeling Index" was calculated by dividing the vessel area in the lesion by the reference segment. Results were correlated to the presence of stenosis (>50% diameter reduction) in invasive angiography. In a subset of 13 patients, MDCT measurements were verified by IVUS.

RESULTS

Reference vessel area was not significantly different between nonstenotic versus stenotic lesions (20 +/- 8 mm(2), n = 23 vs. 22 +/- 8 mm(2), n = 21). The mean Remodeling Index was significantly higher in nonstenotic than in stenotic lesions (1.3 +/- 0.2 vs. 1.0 +/- 0.2, p < 0.001). In five stenotic lesions, "negative remodeling" (Remodeling Index < or = 0.95) was observed. Cross-sectional vessel areas and Remodeling Indices measured by MDCT correlated closely to IVUS (r(2) = 0.77 and r(2) = 0.82, respectively).

CONCLUSIONS

Multidetector spiral CT may permit assessment of remodeling of coronary atherosclerotic lesions in selected data sets of sufficient quality.

Angiographically silent left main disease detected by intravascular ultrasound: a marker for future adverse cardiac events

BACKGROUND

Concomitant moderate obstructive left main (LM) disease is associated with future cardiac events and poor prognosis in patients undergoing percutaneous intervention (PCI). Whether prognosis is similarly effected by LM disease not detected by angiography, but evident on intravascular ultrasound (IVUS) imaging, is not known. The purpose of this study was to evaluate the long-term prognosis of patients with angiographically insignificant LM coronary artery disease undergoing PCI.

METHODS AND RESULTS

One hundred and seven consecutive patients undergoing PCI with angiographically normal or mild LM disease had 2- and 3-dimensional IVUS imaging. IVUS images were digitized, and 3-dimensional reconstruction was performed. Percent diameter and area stenosis by angiography were 4.8% +/- 3.5% and 18.2% +/- 9.8%, respectively. IVUS mean luminal area and area stenosis were 17.9 +/- 5.6 mm2 and 30.2% +/- 14.7%, respectively. Long-term follow-up was available in 102 (95%) patients at a median of 29 (range 8-52) months. Major adverse cardiac events, defined as death (6), myocardial infarction (4), repeat PCI (13), or CABG (16), were associated with female sex (P =.04), diabetes (P =.02), angiographic minimum lumen diameter (P =.04), and IVUS minimum (P =.01) and mean (P =.01) lumen area. Multivariate predictors of late cardiac events were diabetes (hazard ratio 2.69, P =.014) and minimum lumen area by IVUS (hazard ratio 0.59, P =.015).

CONCLUSIONS

Despite being angiographically silent, LM disease detected by IVUS is an independent predictor of cardiac events and may serve as a marker for such events. These data extend the spectrum of LM disease severity and its relationship to cardiac prognosis in patients undergoing PCI.