Pre-existing arterial remodeling is associated with in-hospital and late adverse cardiac events after coronary interventions in patients with stable angina pectoris

Characteristics of basilar artery atherosclerotic plaques in pontine infarctions: A high-resolution magnetic resonance imaging study

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This study used a 3.0T high-resolution magnetic resonance imaging to explore basilar artery plaque characteristics in patients suffering from acute isolated pontine infarction.

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The study also used plaque analysis software to calculate the properties of the plaques and to fully analyze and compare the differences between two types of pontine infarction.

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The result may account for the different prognosis associated with these two types of pontine infarction.

Objective

This study used a 3.0T high-resolution magnetic resonance imaging approach to explore basilar artery plaque characteristics in patients suffering from acute isolated pontine infarction.

Materials and methods

30 consecutive patients suffering from acute isolated pontine infarction were enrolled in this study and underwent examinations including high-resolution MRI assessment of the basilar artery within 7 days following infarction.

Results

The basilar artery plaque burden of 16 patients with paramedian pontine infarction was 0.26±0.085, while the reconstruction index and enhancement rate index values in these patients were 1.097±0.133 and 1.750±0.447, respectively. In the 14 patients suffering from deep pontine infarction, these three values were 0.21±0.055, 0.896±0.223, and 1.285±0.611, respectively.These values differed significantly when comparing patients suffering from paramedian pontine infarction to those suffering from deep pontine infarction.

Conclusion

This study suggests that the characteristics of basilar artery plaques differ between the two subtypes of pontine infarctions, which may account for the differences in prognosis associated with these two infarct subtypes.

Morphologic characteristics of severe basilar artery atherosclerotic stenosis on 3D high-resolution MRI

Background

Two-dimensional high-resolution MRI (2D HRMRI) faces many technical challenges for fully assessing morphologic characteristics of inherent tortuous basilar arteries. Our aim was to investigate remodeling mechanisms and plaque distribution in symptomatic patients with basilar artery stenosis on three-dimensional (3D) HRMRI.

Methods

Forty-six consecutive patients with symptomatic basilar artery atherosclerotic stenosis on MRA (70–99%) were enrolled. The remodeling index (RI) was the ratio of vessel area at the maximal-lumen-narrowing (MLN) site to reference vessel area. RI ≥ 1.05 was defined as positive remodeling (PR), RI ≤ 0.95 as negative remodeling (NR), and 0.95 < RI < 1.05 as intermediate remodeling (IR). The remodeling patterns were divided into two groups (PR and non-PR [NR and IR]). The cross-sectional and longitudinal distribution of BA plaques were evaluated.

Results

Two patients were excluded because of poor-quality images. Images of 44 patients were available for measurements. PR was found in 23 (52.3%) patients, and non-PR in 21 (47.7%) patients. At the MLN sites, vessel area, wall area, plaque size and percentage of plaque burden of PR group were significantly greater than non-PR group (p < .001). Most plaques (90.9%) of the 44 patients were located at the dorsal, left and right walls. For the longitudinal distribution of plaque, 8 (18.2%) and 36 (81.8%) plaques were located in BA proximal and distal to AICA, respectively. Most plaques (68.2%) were eccentrically distributed.

Conclusions

3D HRMRI with postprocessing multiple planar reconstruction is able to evaluate the remodeling pattern and plaque distribution of basilar artery atherosclerotic stenosis, which might be used to guide intracranial intervention.

Smaller outer diameter of atherosclerotic middle cerebral artery associated with RNF213 c.14576G>A Variant (rs112735431)

Background:

Intracranial atherosclerosis (ICAS) involves diverse histologies and several remodeling patterns. Ring finger protein 213 (RNF213) c.14576G>A variant (rs112735431), recently reported to be associated with ICAS, may be linked with negative remodeling (outer diameter – reducing morphological alteration) of intracranial arteries. This study investigated the outer diameter of atherosclerotic middle cerebral artery (MCA).

Methods:

Patients with unilateral atherosclerotic MCA stenosis/occlusion were enrolled in this single-hospital-based case-control study at The University of Tokyo Hospital. The patients were divided into two groups by the presence of RNF213 c.14576G>A (variant group and wild-type group) and the outer diameter of the MCA was measured with high-resolution magnetic resonance imaging.

Results:

Twenty-eight patients with the wild type and 19 patients with the variant type were included. The outer diameter of the stenotic side MCA was smaller in the variant group than in the wild-type group (P = 8.3 × 10^-6). The outer diameter of the normal side MCA was also smaller in the variant group than in the wild-type group (P = 5.2 × 10^-3). The ratio of stenotic side to normal side was also smaller in the variant group than in the wild-type group (P = 1.5 × 10^-5).

Conclusions:

This study indicates that RNF213 c.14576G>A is associated with negative remodeling of ICAS.

High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

OBJECTIVE

To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.

DATE SOURCES

We retrieved information from PubMed database up to December 2015, using various search terms including vessel wall imaging (VWI), high-resolution magnetic resonance imaging, intracranial arterial stenosis, black blood, and intracranial atherosclerosis.

STUDY SELECTION

We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI. We organized this data to explain the value of VWI in clinical application.

RESULTS

VWI with black blood technique could provide high-quality images with submillimeter voxel size, and display both the vessel wall and lumen of intracranial artery simultaneously. Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening, enhancement, and vessel remodeling on VWI. This technique could be used for determining causes of stenosis, identification of stroke mechanism, risk-stratifying patients, and directing therapeutic management in clinical practice. In addition, a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.

CONCLUSIONS

This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

Patterns and Implications of Intracranial Arterial Remodeling in Stroke Patients

BACKGROUND AND PURPOSE

Preliminary studies suggest that intracranial arteries are capable of accommodating plaque formation by remodeling. We sought to study the ability and extent of intracranial arteries to remodel using 3-dimensional high-resolution black blood magnetic resonance imaging and investigate its relation to ischemic events.

METHODS

Forty-two patients with cerebrovascular ischemic events underwent 3-dimensional time-of-flight magnetic resonance angiography and contrast-enhanced black blood magnetic resonance imaging examinations at 3 T for intracranial atherosclerotic disease. Each plaque was classified by location (eg, posterior versus anterior circulation) and its likelihood to have caused a stroke identified on magnetic resonance imaging (culprit, indeterminate, or nonculprit). Lumen area, outer wall area, and wall area were measured at the lesion and reference sites. Plaque burden was calculated as wall area divided by outer wall area. The arterial remodeling ratio (RR) was calculated as outer wall area at the lesion site divided by outer wall area at the reference site after adjusting for vessel tapering. Arterial remodeling was categorized as positive if RR>1.05, intermediate if 0.95≤RR≤1.05, and negative if RR<0.95.

RESULTS

One hundred and thirty-seven plaques were identified in 42 patients (37% [50] posterior and 63% [87] anterior). Compared with anterior circulation plaques, posterior circulation plaques had a larger plaque burden (77.7±15.7 versus 69.0±14.0; P=0.008), higher RR (1.14±0.38 versus 0.95±0.32; P=0.002), and more often exhibited positive remodeling (54.0% versus29.9%; P=0.011). Positive remodeling was marginally associated with downstream stroke presence when adjusted for plaque burden (odds ratio 1.34, 95% confidence interval: 0.99-1.81).

CONCLUSIONS

Intracranial arteries remodel in response to plaque formation, and posterior circulation arteries have a greater capacity for positive remodeling and, consequently, may more likely elude angiographic detection. Arterial remodeling may provide insight into stroke risk.

Morphologic characteristics of atherosclerotic middle cerebral arteries on 3T high-resolution MRI

BACKGROUND AND PURPOSE

There are limited studies on the morphologic characteristics of MCA atherosclerotic stenosis. Our aim was to quantitatively assess the remodeling pattern and plaque distribution of atherosclerotic MCAs with 3T high-resolution MR imaging.

MATERIALS AND METHODS

Eighty-seven consecutive patients with symptomatic atherosclerotic stenoses at the M1 segment of the MCA on DSA (50%-99%) were enrolled. The remodeling index was calculated as the Vessel Area at Maximal Lumen Narrowing/Reference Vessel Area. A remodeling index ≥ 1.0 was defined as positive remodeling, and a remodeling index < 1.0, as negative remodeling. Plaque distribution at the maximal lumen narrowing site was classified on the basis of the involvement of the superior, inferior, dorsal, or ventral MCA wall.

RESULTS

Forty-three of 87 patients were excluded due to poor imaging quality (n = 8) or scan plane obliquity secondary to a tortuous M1 segment of the MCA or an MCA ostium lesion or angled lesion (n = 35). Of 44 patients in the final analysis, negative remodeling was found in 19 (43.2%) lesions, and positive remodeling, in 25 (56.8%) lesions. At maximal lumen narrowing sites, lesions with negative remodeling had less vessel area, wall area, and percentage of plaque burden (P < .0001) and a lower eccentricity index (P = .023), compared with lesions with positive remodeling. The plaque involved the superior and dorsal walls in 15 (34.1%) of 44 patients.

CONCLUSIONS

2D high-resolution MR imaging can help assess the remodeling pattern and plaque distribution of MCA stenosis, but the imaging and postprocessing protocol for remodeling assessment needs to be improved in the tortuous course of the MCA and in MCA ostium or angled lesions.

Effect of culprit-lesion remodeling versus plaque rupture on three-year outcome in patients with acute coronary syndrome

To investigate intravascular ultrasound predictors of long-term clinical outcome in patients with acute coronary syndrome, 94 patients with a first acute coronary syndrome with both preintervention intravascular ultrasound imaging and long-term follow-up were enrolled in this study. Remodeling index was defined as external elastic membrane cross-sectional area at the target lesion divided by that at the proximal reference. Arterial remodeling was defined as either positive (PR: remodeling index >1.05) or intermediate/negative remodeling (remodeling index < or =1.05). Clinical events were death, myocardial infarction, and target-lesion revascularization. Patients were followed up for a mean of 3 years. PR was observed in 50 (53%), and intermediate/negative remodeling, in 44 (47%). During the 3-year follow-up, there were 20 target-lesion revascularization events and 5 deaths (2 cardiac and 3 noncardiac), but no myocardial infarctions. Patients with PR showed significantly lower major adverse cardiac event (MACE; death, myocardial infarction, and target-lesion revascularization)-free survival (log-rank p = 0.03). However, patients with plaque rupture showed a nonsignificant trend toward lower MACE-free survival (p = 0.13), but there were no significant differences in MACE-free survival between those with single versus multiple plaque ruptures. Using multivariate logistic regression analysis, only culprit lesion PR was an independent predictor of MACEs (p = 0.04). In conclusion, culprit-lesion remodeling rather than the presence or absence of culprit-lesion plaque rupture was a strong predictor of long-term (3-year) clinical outcome in patients with acute coronary syndrome.

Impact of arterial remodelling and plaque rupture on target and non-target lesion revascularisation after stent implantation in patients with acute coronary syndrome: an intravascular ultrasound study

OBJECTIVES

To investigate the impact of arterial remodelling on long-term clinical outcome after stent implantation in patients with acute coronary syndrome (ACS).

METHODS

134 patients with ACS were enrolled. External elastic membrane (EEM) cross-sectional area (CSA) and lumen CSA were measured. Plaque and media CSA was calculated as EEM minus lumen CSA. Final minimal stent area (MSA) was also measured after stenting. Positive remodelling (PR) was defined as the ratio of the EEM CSA at the target lesion to that at the proximal reference of >1.05, and intermediate or negative remodelling (IR/NR) was defined as that of < or =1.05.

RESULTS

Although final MSA was similar, target lesion revascularisation (TLR) rates at 2 years were significantly higher in patients with PR (33.7%) than in those with IR/NR (13.7%; p = 0.01). In addition, non-TLR rates were also significantly higher in patients with PR (42.2%) than in those with IR/NR (23.5%; p = 0.03). Cardiac event-free survival (for events such as death, myocardial infarction, TLR and non-TLR) was significantly lower in patients with PR than in those with IR/NR (log rank, p = 0.001). By multivariate logistic regression analysis, PR (chi2 6.57, OR 2.70; 95% CI, 1.27 to 5.78; p = 0.01) and plaque rupture (chi2 4.17, OR 2.38; 95% CI, 1.04 to 5.45; p = 0.04) were independent predictors of cardiac events.

CONCLUSION

In patients with ACS, PR and intravascular ultrasound findings that may correspond with plaque rupture predict cardiac events including both TLR and non-TLR at 2 years.

Elevated homocysteine levels might be associated with coronary artery remodeling in patients with stable angina: an intravascular ultrasound study

BACKGROUND

The relationship between plasma biologic markers and coronary artery remodeling is unknown.

HYPOTHESIS

Plasma biologic markers are associated with coronary artery remodeling.

METHODS

Preintervention intravascular ultrasound images were obtained in 44 patients with chronic stable angina. Plasma samples were collected 24 h before coronary intervention. The biologic markers included total cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, lipoprotein(a) [LP(a)], C-reactive protein (CRP), and homocysteine. The remodeling index (RI) was defined as a ratio of the (lesion/proximal reference) external elastic membrane cross-sectional area. Positive remodeling was defined as an RI > 1.05, negative remodeling as an RI <0.95, and intermediate remodeling as an RI between 0.95 and 1.05.

RESULTS

Total cholesterol level (r = 0.092, p = 0.557), LDL cholesterol level (r = 0.123, p = 0.426), triglyceride level (r = 0.020, p = 0.901), HDL cholesterol level (r = 0.042, p = 0.789), LP(a) level (r = 0.062, p = 0.729), and CRP level (r = 0.266, p = 0.089) did not significantly correlate with the RI. However, the plasma homocysteine level positively correlated with the RI (r = 0.398, p = 0.008). The plasma homocysteine level was significantly lower in the lesions with negative remodeling and higher in the lesions with positive remodeling (10.8 +/- 0.7 micromol/l in negative remodeling, 13.1 +/- 0.6 micromol/l in intermediate remodeling, and 18.1 +/- 2.8 micromol/l in positive remodeling, p = 0.021).

CONCLUSIONS

Elevated homocysteine levels might be associated with coronary artery remodeling in patients with stable angina.

Remodeling Index Compared to Actual Vascular Remodeling in Atherosclerotic Left Main Coronary Arteries as Assessed With Long-Term (≥12 Months) Serial Intravascular Ultrasound

OBJECTIVES

We present the remodeling index (RI) versus serial intravascular ultrasound (IVUS) data.

BACKGROUND

The RI, derived by comparing lesion external elastic membrane (EEM) cross-sectional area versus the reference at one time point, is used in various IVUS studies as a substitute of true remodeling (change in EEM over time), assuming that it represents true remodeling.

METHODS

We studied 46 non-stenotic left main arteries using serial IVUS (follow-up 18 +/- 8 months). Plaques were divided into subgroups according to the follow-up RI: follow-up RI >1 (n = 27) versus follow-up RI < or =1 (n = 19).

RESULTS

Lesions with a follow-up RI >1 had an increase in lumen despite an increase in plaque because of an increase in EEM. Conversely, lesions with a follow-up RI < or =1 had a reduction in lumen as a result of both a plaque increase and EEM decrease. Overall, the follow-up RI correlated directly with changes in lesion site EEM (baseline-to-follow-up). Although there was no correlation between the follow-up RI and changes in reference EEM area, changes in reference EEM area did correlate directly with changes in lesion EEM area. In nearly 90% of lesions with a follow-up RI >1, there was a previously documented increase in EEM area. Using multivariate linear regression analysis, the follow-up RI was dependent on the baseline RI, the increase in lesion EEM area, and the decrease in reference EEM area. The follow-up RI was not dependent on changes in lesion plaque area.

CONCLUSIONS

The vast majority of left main lesions with a remodeling index >1 had evidence of a previous increase in lesion-site EEM area.

Study of the Predictors and Lesion Characteristics of Ischemic Heart Disease Patients With False Negative Results in Stress Myocardial Perfusion Single-Photon Emission Tomography

BACKGROUND

The predictors and lesion morphology of patients with ischemic heart disease testing false negative results in stress myocardial perfusion single-photon emission computed tomography (SPECT) was investigated.

METHODS AND RESULTS

Subjects were 58 consecutive patients who underwent coronary angiography (CAG), even though they showed normal findings in stress myocardial perfusion SPECT. Age, gender, methods of stress, perfusion agent, coronary risk factors, angina symptoms, and electrocardiographic changes were investigated as predictors by multivariate analysis. For lesion morphology, significant stenotic lesions were studied for morphological characteristics and reference diameter (RD), percentage diameter stenosis (%DS), minimum lumen diameter (MLD), and lesion length (LL) were measured. CAG revealed 30 significant stenotic lesions in 18 patients. Logistic regression analysis revealed significant predictors to be age (odds ratio (OR) 1.118, p<0.05), typical anginal pain (OR 21.09, p<0.01), and hypertension (OR 8.336, p<0.05). For lesion morphology, there were only 2 diffuse lesions and the mean RD, %DS, MLD, and LL were 3.03+/-0.9 mm, 63.1 +/-9.3%, 1.13+/-0.49 mm, and 13.2+/-7.0 mm, respectively.

CONCLUSION

Sufficient caution is believed necessary in the interpretation of normal findings of stress myocardial perfusion SPECT when the patient is elderly, complains of typical anginal pain, or has hypertension. In regard to characteristics of lesion morphology, there were hardly any diffuse lesions.

Impact of intravascular ultrasound lesion characteristics on neointimal hyperplasia following sirolimus-eluting stent implantation

The effect of lesion characteristics on neointimal hyperplasia after sirolimus-eluting stent implantation was examined in 45 patients who underwent successful preinterventional intravascular ultrasound. There were no differences in neointimal hyperplasia between the moderate/severe calcified lesion group (calcium arc >120 degrees ) and the non/mild calcified lesion group or between the positive vessel remodeling group (external elastic membrane area at the minimal lumen area site larger than that at the proximal reference site) and negative vessel remodeling group. No correlation between preinterventional plaque burden and neointimal hyperplasia was found. In patients who have coronary artery disease, sirolimus-eluting stents continue to demonstrate striking suppression of neointimal proliferation, irrespective of lesion characteristics previously associated with greater restenotic risk.

Cumulative incidence of coronary lesions with vulnerable characteristics in patients with stable angina pectoris: an intravascular ultrasound and angiographic study

BACKGROUND

Development of vulnerable lesion may take place simultaneously at many sites of coronary vasculature, therefore causing multisite instability. The prevalence of the phenomenon in stable angina (SA) patients remains unknown. The aim of our study was to assess, in patients with stable angina, the prevalence of coronary plaques with vulnerable characteristics and to ascertain whether the number of such lesions may accumulate.

METHODS

Vulnerable plaques are characterised by positive remodelling on intravascular ultrasound (IVUS) and with complex appearance on angiography. We performed preprocedural IVUS in target lesion of 67 patients with SA (46 males, age 55.9). Remodelling index (RI) defined as vessel area at the target lesion divided by that of average reference segments > or = 1.05 was assumed as positive remodelling. Plaques of > or = 30% stenosis on angiography were classified into complex or smooth groups.

RESULTS

Positive remodelling was found in 30 (44.8%) and complex plaque in 16 (23.9%) of 67 target lesions. Multiple complex plaques were present in 21 (31.3%) patients. Plaques with positive remodelling more often were complex on angiography (12/30 vs. 4/37, respectively; p=0.005) and were more often associated by complex plaques at other sites (35/30 vs. 23/37; p=0.04) than the remaining lesions. Moreover, the presence of positive remodelling predicted multiple complex lesions at other sites (OR 5.6; 95% CI 1.7-18.3).

CONCLUSION

Multiple coronary plaques with vulnerable characteristics are present in nearly one third of patients with stable angina. Incidence of vulnerable lesions may have cumulative character, i.e. the presence of one vulnerable lesion predicts occurrence of further vulnerable plaques.

Impact of different definitions on the interpretation of coronary remodeling determined by intravascular ultrasound

The objective of this study was to compare the categorizations and determinants related to remodeling by the three definitions commonly used. Several morphological and intravascular ultrasound (IVUS) studies have demonstrated the fundamental importance of arterial remodeling in atherosclerosis. However, lack of consensus on how to define remodeling has led to conflicting analyses of factors that influence this process. Analysis of pre-interventional IVUS images of 514 lesions in native coronary arteries was performed. Arterial remodeling was defined as outward by definition 1, when [cross-sectional area (CSA) of the external elastic membrane (EEM) at the lesion site (EEM(lesion))]/[EEM CSA either at the proximal (EEM(prox ref)) or distal (EEM(distal ref)) reference site with the least amount of plaque] was > 1.05, intermediate when this ratio was between 0.95 and 1.05, and inward when < 0.95. Remodeling was defined as outward by definition 2 when EEM(lesion) > both EEM(prox ref) and EEM(distal ref), inward when EEM(lesion) < both EEM(prox ref) and EEM(distal ref), and intermediate when EEM(lesion) was intermediate between EEM(prox ref) and EEM(distal ref). By definition 3, vessel remodeling was defined as outward when EEM(lesion) > (EEM(prox ref) + EEM(distal ref))/2 and intermediate/inward when EEM(lesion) < or = (EEM(prox ref) + EEM(distal ref))/2. The frequency of outward remodeling was significantly higher by definitions 1 and 3 than by definition 2, whereas a higher frequency of inward remodeling was observed in definition 1, resulting in significantly different remodeling distributions between the three definitions (P < 0.0001). By multivariate logistic analysis, the only clinical determinants related to outward remodeling was younger age, and only by definition 3. IVUS determinants varied significantly between the three definitions. The only consistent determinants among the three definitions were smaller lumen CSA at the reference site and larger plaque + media CSA at the lesion site. This study demonstrates the significant impact of different remodeling definitions on the incidence and determinants of remodeling patterns. The marked variability in categorization of remodeling underscores the importance of developing a standard methodology.

Metabolic syndrome-mediated inflammation following elective percutaneous coronary intervention

There are few data concerning the relationship between diabetes mellitus, the metabolic syndrome and inflammation following elective percutaneous coronary intervention (PCI). The purpose of this study was to assess basal and peak levels of candidate cytokines in 40 patients undergoing elective PCI. Patients were categorised as having diabetes mellitus, the metabolic syndrome, or neither. Patients with the metabolic syndrome exhibited significantly greater levels of tumour necrosis factor-alpha over the study period, although this was unrelated to PCI. There was a trend for increased levels of interleukin-6 following PCI, primarily among patients with metabolic syndrome. Basal levels of monocyte chemoattractant protein-1 (MCP-1) were not different among study groups; however, the metabolic syndrome cohort had a trend towards increased circulating levels of MCP-1 after PCI. In this patient population, the metabolic syndrome correlates with a heightened inflammatory response following elective PCI.

Expansive arterial remodeling: location, location, location

The artery is a dynamic organ capable of changing its geometry in response to atherosclerotic plaque formation. Expansion of the vessel diameter retards luminal narrowing and is considered a compensatory response. However, the expansive remodeling response is a "wolf in sheep's clothes," because expansion is associated with the presence of inflammatory cells, proteolysis, and a thrombotic plaque phenotype. The prevalence and clinical presentation of expansively remodeled lesions may differ among vascular beds. However, it is evident that all types of atherosclerotic arterial expansive lesions share the presence of inflammatory cells and subsequent protease activities. The potential role of inflammation and protease activity in the development of the different remodeling modes is discussed.

Effect of preintervention remodeling type on subsequent coronary artery behavior after directional atherectomy

To evaluate the influence of preintervention remodeling on subsequent vessel behavior after directional coronary atherectomy (DCA) under intravascular ultrasound (IVUS) guidance, serial (before and after DCA and at 6-month follow-up) IVUS data were analyzed for 246 lesions that were classified into 2 categories: positive remodeling (PR) in 77 lesions versus intermediate or negative remodeling in 169 lesions. Although the 2 groups had similar baseline characteristics, IVUS data showed that the PR group had a greater acute lumen area (LA) gain without an increased late LA loss, resulting in a greater net (acute plus late) LA gain and follow-up LA. This suggests that IVUS-guided DCA may neutralize the negative impact of preintervention PR on late vessel patency.

Association between plasmin activation system and intravascular ultrasound signs of plaque instability in patients with unstable angina and non-st-segment elevation myocardial infarction

BACKGROUND

The association between intravascular ultrasound (IVUS) signs of plaque instability and plasma levels of biomarkers was determined in patients with unstable angina and non-ST-segment elevation myocardial infarction (UA/NSTEMI).

METHODS

Fifty-two patients underwent coronary angiography and IVUS 8 +/- 5 hours after the onset of chest pain. IVUS analysis included plaque morphology, disruption, thrombi and eccentricity, lumen, external elastic membrane, and plaque plus media areas of culprit lesion and reference segments and arterial remodeling. Plasma levels of the thrombin activation system (thrombin-antithrombin complex [TAT], tissue factor pathway inhibitor [TFPI], and prothrombin fragments 1+2 [F1+2]) and plasmin activation system (tissue and urokinase-type plasminogen activator [t-PA and u-PA], plasminogen activator inhibitor-1 [PAI-1], and D-dimer) were measured with enzyme-linked immunosorbent assay kits before angiography.

RESULTS

Elevated levels of TAT (7.2 +/- 6.0 microg/L), F1+2 (1.8 +/- 1.0 nmol/L), TFPI (179.1 +/- 131.0 ng/mL), PAI-1 (95.4 +/- 54.6 ng/mL), t-PA (10.6 +/- 8.8 ng/mL), and u-PA (2.6 +/- 0.9 ng/mL) were found in patients with UA/NSTEMI. The serum levels of D-dimer (40.0 +/- 39.5 ng/mL) remained in reference range. Expansive and constrictive remodeling were found in 18 (35%) and 12 (23%) patients, respectively. Expansive remodeling of the culprit lesion was associated with significantly higher plasma levels of PAI-1 (121.6 +/- 55.0 vs 87.7 +/- 61.5 and 77.4 +/- 42.8 ng/ml, P =.039), and u-PA (3.0 +/- 1.2 vs 2.2 +/- 0.5 and 2.5 +/- 0.7 ng/mL, P =.026) as compared with constrictive and neutral remodeling. Increased plasma levels of u-PA were associated with plaque rupture (3.0 +/- 0.7 vs 2.5 +/- 0.9 ng/mL, P =.062). Plasma levels of PAI-1 and u-PA correlated positively with plaque plus media (P =.0297 and P =.0093) and external elastic membrane areas (P =.010 and P =.0002).

CONCLUSIONS

Elevated levels of biomarkers of plasmin activation system are associated with signs of plaque instability of culprit lesion in UA/NSTEMI and might therefore serve as non-invasive determinants of the population that is at high risk for subsequent adverse events.

Coronary plaque burden detected by multislice computed tomography after acute myocardial infarction with near-normal coronary arteries by angiography

Nonsignificant coronary artery plaque rupture or erosion may be the origin of acute myocardial infarction (AMI). The aim of our study was to assess the ability of multislice computed tomography (MSCT) to detect coronary plaques responsible for near normal coronary angiography AMI. Eight patients with presentation of AMI and no significant coronary narrowing by angiography were enrolled. Two groups were defined: (1) true AMI and (2) myocarditis. MSCT was able to detect nonsignificant coronary soft plaques responsible for AMI and has provided information on plaque volume, eccentricity, and density. In patients with myocarditis, there was no evidence of plaque.

Impact of preinterventional arterial remodeling on neointimal hyperplasia after implantation of (non-polymer-encapsulated) paclitaxel-coated stents: a serial volumetric intravascular ultrasound analysis from the ASian Paclitaxel-Eluting Stent Clinical Trial (ASPECT)

BACKGROUND

This study used serial volumetric intravascular ultrasound (IVUS) to evaluate the effect of preinterventional arterial remodeling on in-stent intimal hyperplasia (IH) after implantation of non-polymer-encapsulated paclitaxel-coated stents.

METHODS AND RESULTS

Patients were randomized to placebo or one of two doses of paclitaxel (low dose, 1.28 microg/mm2; high dose, 3.10 microg/mm2). Complete preinterventional, post-stent implantation, and follow-up IVUS were available in 18 low-dose and 21 high-dose patients. IH volumes were similar in low-dose and high-dose patients: 17.6+/-15.1 mm3 in low-dose patients and 13.1+/-13.3 mm3 in high-dose patients (P=0.3). Therefore, IVUS findings in low- and high-dose patients were combined. Preinterventional remodeling was assessed by comparing lesion site to proximal and distal reference arterial area: positive remodeling (lesion>proximal reference, n=13), intermediate remodeling (distal reference<lesion<proximal reference, n=13), and negative remodeling (lesion<distal reference, n=13). During follow-up, there was a decrease in lumen volume in positive remodeling lesions (from 106+/-30 to 90+/-27 mm3; P=0.0067) and in intermediate remodeling lesions (from 97+/-28 to 76+/-31 mm3; P=0.0004), but not in negative remodeling lesions (99+/-27 versus 92+/-32 mm3; P=0.15). The follow-up IH volume was lower in negative remodeling lesions (5+/-7 mm3) compared with positive remodeling (20+/-14 mm3; P=0.0051) and intermediate remodeling lesions (20+/-15 mm3; P=0.0043); however, IH volume was virtually identical in positive and intermediate remodeling lesions. Multivariate linear regression analysis determined that remodeling and inflation pressure were independent predictors of IH volume; variables tested in the model included diabetes, acute coronary syndromes, dose, remodeling, and preinterventional plaque burden.

CONCLUSIONS

Preinterventional arterial remodeling, especially negative remodeling, influences neointimal hyperplasia suppression after implantation of non-polymer-encapsulated paclitaxel-coated stents.

Preintervention arterial remodeling affects vessel stretch and plaque extrusion during coronary stent deployment as demonstrated by three-dimensional intravascular ultrasound

The mechanisms of lumen enlargement during stent implantation may be significantly affected by arterial remodeling. To assess effects of lesion remodeling, we performed 3-dimensional intravascular ultrasound (IVUS) analyses in 55 coronary lesions before and after deployment of balloon-expandable stents. Standard quantitative analysis was performed, and arterial remodeling was assessed by the remodeling index (target site divided by mean of proximal and distal reference segment vessel areas), which classified lesions into group A (remodeling index < or =1, negative or intermediate remodeling, n = 40) or group B (remodeling index >1, positive remodeling, n = 15) lesions. Characteristics of the 55 patients and the interventional procedures were similar in the 2 groups. IVUS demonstrated that stenting resulted in increased lumen and vessel dimensions and in a reduced plaque size (p < or =0.001 each) in both group A and group B lesions. The extent of lumen increase inside the stents was almost identical, but resulted from different mechanisms: (1) vessel stretch was greater in group A (p <0.002 at minimum lumen site); (2) plaque compression (or embolization) tended to be greater in group B (p = 0.05, along entire stented segment); (3) plaque redistribution within the stent was observed in both groups (p <0.005 both); and (4) significant (p <0.01) plaque extrusion into the distal reference segment was found in group B only. Thus, the remodeling pattern of coronary lesions has a significant impact on the mechanisms of lumen enlargement during stent deployment. Lesions with positive remodeling show more plaque extrusion into the distal reference and less stent-induced vessel stretch than those with negative remodeling.

Coronary arterial remodeling: from bench to bedside

Coronary arterial remodeling describes changes of vessel size at the site of atherosclerotic lesions. Positive remodeling (expansion) of early lesions maintains lumen size despite plaque accumulation. In contrast, negative remodeling (shrinkage) contributes to luminal stenosis independent of plaque accumulation. Because of these adaptive changes, plaque progression/regression is not closely reflected in luminal size. Histologic studies have demonstrated that the pathophysiologic role of arterial remodeling is more complex than a mere compensatory process. Surprisingly, there is a consistent association between positive arterial remodeling, local inflammatory response, and plaque vulnerability. In vivo tomographic imaging techniques, in particular intravascular ultrasound, and potentially computed tomography and magnetic resonance imaging, allow the observation of remodeling in clinical settings. The integration of basic knowledge about arterial remodeling with clinical observations from in vivo imaging could lead to a better understanding of plaque progression, regression, and vulnerability and may eventually have implications for disease prevention.

Increased intimal apoptosis in coronary atherosclerotic vessel segments lacking compensatory enlargement

OBJECTIVES

In a histopathologic study, we assessed the balance of cell proliferation and apoptosis by counting the number of apoptotic and proliferating cell nuclear antigen-positive cells in freshly harvested atherectomy specimens from 34 patients.

BACKGROUND

Remodeling of human coronary arteries is an adaptive process that alters vascular lumen size.

METHODS

Intravascular ultrasound was performed prior to atherectomy. Total vessel area (area within the external elastic lamina [EEL]), lumen area and plaque area were measured at the region of interest (ROI), and at a proximal and distal reference segment, utilizing the formula Delta(%)=100x(ROI-reference segment)/reference segment. Positive arterial remodeling (R+) resulting in luminal expansion was defined as DeltaEEL >10%. Absence of remodeling (0 < DeltaEEL <10%) and constrictive arterial remodeling (DeltaEEL <0) were considered as neutral remodeling (R0) and negative remodeling (R-), respectively.

RESULTS

In R- lesions, apoptotic indices (APO) were significantly elevated (17.17 +/- 2.19%) compared with R+ lesions (4.89 +/- 1.7%; p = 0.0007). In a rabbit iliac percutaneous transluminal coronary angioplasty model intimal apoptosis was increased four weeks after balloon angioplasty injury (APO 8.8 +/- 0.03%) compared with contralateral untreated segments (APO 3.0 +/- 0.04%, n = 6). Lesions with an EEL/intimal area <3.0 showed significantly more intimal apoptosis than untreated lesions (p = 0.02).

CONCLUSIONS

The data indicate that constrictive remodeling of atherosclerotic coronary lesions is associated with increased apoptosis of intimal cells. We speculate that increased apoptosis is due to extensive plaque healing after episodes of symptomatic or asymptomatic plaque rupture.

What has intravascular ultrasound taught us about plaque biology?

Intravascular ultrasound (IVUS) has a defined role in the cardiac catheterization laboratory to assess lesion severity and the procedural success of vascular interventions. However, IVUS has also contributed to our understanding of the biology of atherosclerosis and restenosis. In acute coronary syndromes, IVUS has revealed varying degrees of stenosis, thrombosis, and plaque derangement typical of the plaque disruption seen in many pathologic studies of patients who have died of this condition. IVUS has demonstrated that the culprit lesions of patients surviving acute coronary syndromes also tend to be softer, with less calcium, and tend to have more plaque with positive arterial remodeling (compensatory enlargement) than lesions causing stable coronary syndromes. Arterial remodeling is also an important component of restenosis after coronary interventions. IVUS has suggested that interventions that reduce restenosis tend to have a greater impact on preventing negative remodeling (constriction) rather than reducing neointimal proliferation. Oxidant stress may be an important contributor to negative remodeling, as IVUS has demonstrated this anatomy at sites of coronary artery spasm. Positive remodeling seen by IVUS is also associated with impaired endothelial vasomotor dysfunction, and IVUS studies have demonstrated the contribution of vasomotor tone to arterial elasticity. Future directions include integrating IVUS with other imaging modalities, such as angiography, to study the interaction of anatomic and physiologic factors in atherosclerosis progression, and using the raw ultrasound signal to distinguish plaque components and differences in wall strain that may identify vulnerable plaques.

Directional coronary atherectomy: the Vienna experience

BACKGROUND

Several multicenter trials have shown excellent results for directional coronary atherectomy (DCA) in a selected patient cohort. To prove the applicability of this method in daily clinical routine and a nonselected patient cohort, we analyzed 46 consecutive cases performed at our catheterization lab.

METHODS

DCA was performed as a routine procedure in 45 suitable patients. Balloon dilatation or stent implantation postprocedure was accomplished only in case of unsatisfactory results. Quantitative coronary angiography was achieved pre- and postprocedure as well as at 6-month follow-up.

RESULTS

Optimal atherectomy < 20% residual stenosis was reached in 24 (52%) of 46 target lesions and a residual stenosis < 50% in 46 (100%) lesions. Procedure-related complications occurred in three (6%) patients (one major complication, death, < 24 hours, 2%; two minor complications, pseudoaneurysm, 4%). The 6-month angiographic follow-up revealed a binary restenosis rate of 29% (n = 11). Ten out of 11 restenotic lesions required revascularization. When patients were stratified in two groups according to their preprocedural minimal lumen diameter (MLD), this parameter proved to be a very strong predictor of outcome. The percentage of restenosis was significantly higher in patients with an MLD > 1.60 mm compared to patients with a smaller MLD (54% vs 19.3%; P < 0.0001). Reference vessel diameter preprocedure did not differ significantly.

CONCLUSIONS

Our study demonstrated that DCA is a suitable technique for the daily clinical routine, as the rates of complications and restenosis were similar to that in a highly selective patient cohort. Additionally, our study showed that patient selection should include preprocedural analysis of MLD in order to achieve optimal results. Therefore, atherectomy yielded comparable results to other conventional techniques and may be used instead of or in combination with them.