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

Clinical factors associated with slow flow in left main coronary artery-acute coronary syndrome without cardiogenic shock

Since slow flow can be a fatal complication in left main coronary artery (LMCA)-acute coronary syndrome (ACS) patients, it should be important to anticipate and prepare slow flow during primary PCI for LMCA-ACS. We hypothesized that intravascular ultrasound (IVUS) findings would be useful to predict slow flow for LMCA-ACS patients without cardiogenic shock (CS). The purpose of this study was to investigate clinical factors associated with slow flow in LMCA-ACS patients without CS. We included 60 LMCA-ACS patients without CS, and divided into the slow flow group (n = 18) and the non-slow flow group (n = 42). Slow flow was defined as either transient or persistent TIMI flow grade ≤ 2. The prevalence of ST-segment elevation myocardial infarction (STEMI) was significantly higher in the slow flow group (55.6%) than in the non-slow flow group (11.9%) (p = 0.002). In the IVUS analysis, remodeling index was significantly greater in the slow flow group (1.15 ± 0.17) than in the non-slow flow group (0.99 ± 0.11) (p = 0.001). The multivariate logistic regression analyses in the IVUS factors revealed that remodeling index was significantly associated with slow flow (0.1 increase: OR 2.238, 95% CI 1.144-4.379, p = 0.019). In conclusion, remodeling index was significantly associated with slow flow. Our results suggest that the remodeling index determined by IVUS would be useful to find high-risk features of slow flow in LMCA-ACS patients without CS.

Changes in the Common Carotid Artery after Radiotherapy: Wall Thickness, Calcification, and Atherosclerosis

BACKGROUND AND PURPOSE

Since the long-term survival rate has improved in laryngeal cancer patients who receive radiotherapy, concerns about postradiation complications (including carotid atherosclerosis) have increased. We followed changes in the common carotid artery (CCA) after radiotherapy and identified the underlying risk factors.

METHODS

Consecutive patients with laryngeal cancer who underwent radiotherapy between January 1999 and December 2009 and who had received computed tomography (CT) both pre- and postradiotherapy were enrolled. Changes in the wall thickness and in the vessel and lumen areas as well as the presence of calcification or atherosclerosis were investigated. Demographics and risk factors were compared between patients with and without atherosclerosis at follow-up CT.

RESULTS

In total, 125 patients were enrolled. The wall thickness had increased and the lumen area had decreased several months after radiotherapy. These changes were not associated with vascular risk factors and were not progressive. Calcification and atherosclerosis were observed in 37 (29.6%) and 71 (56.8%) patients, respectively. Diabetes was associated with calcification (p=0.02). The prevalence of hyperlipidemia was higher in patients with atherosclerosis (28.2% vs. 11.1%, p=0.02) and for a longer period postradiation [62.7±32.1 vs. 40.0±24.2 months (mean±SD), p<0.001]. Atherosclerosis occurred mostly in the middle portion of the CCA (n=31, 24.6%), followed by the proximal CCA at the intrathoracic level (n=26, 20.6%) and the distal CCA (n=6, 4.8%). Positive remodeling was also observed, but this was less common in patients with calcification (p=0.02).

CONCLUSIONS

Various types of postradiation changes occur in the CCA and can be easily observed in postradiation CT. The prevalence and burden of postradiation atherosclerosis increased in a close relationship with baseline cholesterol levels and the time after radiotherapy. Postradiation atherosclerosis was observed at unusual sites of the CCA.

Coronary plaque characteristics that indicate distal embolization during percutaneous coronary intervention in patients with stable angina-virtual histology intravascular ultrasound study

Distal embolization (DE) is a serious complication of percutaneous coronary intervention (PCI) in patients with stable angina. The purpose of this study was to evaluate the coronary plaque characteristics that indicate DE during PCI in patients with stable angina using virtual histology intravascular ultrasound (VH-IVUS). Three hundred and sixty-four consecutive stable angina patients who underwent PCI were enrolled in this study. The patients were divided into two groups as follows: patients exhibiting DE (DE group, n = 10) and patients without DE (non-DE group, n = 354). Coronary plaque compositions were assessed by VH-IVUS. The fibro-fatty (FF) ratio (28 ± 17 vs. 11 ± 9 %, p < 0.0001) was higher in the DE group compared with the non-DE group. The best cut-off value of FF ratio for prediction of DE was 20 %, with a sensitivity of 0.80 and a specificity of 0.81 (odds ratio; 17.1, 95 % confidence interval 3.56-82.5, p = 0.0004). Coronary plaques with a high FF ratio may be the predictor of indicating DE in patients with stable angina during PCI.

Positive remodeling is associated with vulnerable coronary plaque components regardless of clinical presentation: virtual histology-intravascular ultrasound analysis

OBJECTIVE

We used virtual histology-intravascular ultrasound (VH-IVUS) to evaluate the relation between coronary artery remodeling pattern and plaque components in 1133 patients.

METHODS

We divided the patients into two groups according to the remodeling pattern as positive remodeling (PR, remodeling index>1.05) (n=192) and intermediate remodeling (IR, remodeling index ≤ 1.05 and ≥ 0.95)/negative remodeling (NR, remodeling index<0.95) (n=941). VH-IVUS analysis classified the color-coded tissue into four major components: green (fibrotic, FT); yellow-green (fibro-fatty); white (dense calcium); and red (necrotic core, NC). Thin-cap fibroatheroma (TCFA) was defined as focal, NC-rich (≥ 10% of the cross-sectional area) plaques being in contact with the lumen in a plaque burden ≥ 40%.

RESULTS

At the minimum lumen site, PR group had greater plaque plus media area (12.8 ± 4.9 vs. 9.9 ± 3.8mm(2), p<0.001) and greater %NC area (21.7 ± 12.3 vs. 18.2 ± 11.6%, p<0.001) and smaller %FT area (57.0 ± 14.5 vs. 59.4 ± 14.6%, p=0.037) compared with IR/NR group. PR group had greater plaque volume (188 ± 150 vs. 135 ± 130 mm(3), p<0.001) and greater %NC volume (19.1 ± 9.6 vs. 16.6 ± 9.2%, p=0.001) and smaller %FT volume (58.3 ± 11.7 vs. 60.6 ± 11.0%, p=0.009) compared with IR/NR group. PR group had more TCFA compared with IR/NR group (21% vs. 13%, p=0.006). Similar findings about plaque components were observed in terms of greater %NC volume and smaller %FT volume in PR group compared with IR/NR group in patients with both acute coronary syndrome and stable angina.

CONCLUSIONS

VH-IVUS analysis demonstrates that PR was associated with more vulnerable plaque components compared with IR/NR regardless of their clinical presentation.

Relationships between inflammatory mediators and coronary plaque composition in patients with stable angina investigated by ultrasound radiofrequency data analysis

Inflammation has been recognized as a critical process in the progression of coronary atherosclerosis. Virtual Histology-intravascular ultrasound (VH-IVUS) has been reported to be a useful tool for tissue characterization of coronary atherosclerotic plaque. We investigated relationships between plaque composition and inflammation-related factors possibly contributing to atheromatous plaque formation and progression, since these are largely unknown. Using VH-IVUS, we measured plaque volume and composition at the culprit lesions in patients with stable angina undergoing elective percutaneous coronary intervention (n = 33, 39 de novo lesions), and then analyzed correlations between plaque components and serum levels of inflammatory factors in both aorta and culprit coronary artery obtained by aspiration using a distal protection device. Linear regression analysis revealed that both aortic and coronary LDL cholesterol levels correlated with %plaque burden along the culprit lesions (r = 0.535 and 0.539, respectively), but with none of the plaque components. Of %plaque components, fibro-fatty (FF) correlated positively with both aortic and coronary T cell/B cell ratios (r = 0.335 and 0.359, respectively) whereas necrotic core (NC) correlated negatively with both aortic and coronary T cell/B cell ratios (r = -0.373 and -0.483, respectively). These results suggest that LDL cholesterol may be a good marker for total coronary plaque volume whereas the lymphocyte subset of T cell/B cell ratios may be a good marker for plaque composition, especially FF and NC components volume.

Difference of culprit plaque composition between patients with and without pre-infarction angina: an intravascular ultrasound radiofrequency analysis

AIMS

This study was performed to assess the differences in culprit plaque composition between patients with and without pre-infarction angina (PA) by using spectral analysis of intravascular ultrasound (IVUS) radiofrequency (RF) data.

METHODS AND RESULTS

Of 57 patients consecutively admitted to our institution with acute myocardial infarction, pre-intervention IVUS RF data of culprit plaques were obtained and analysed in 35 patients after percutaneous aspiration thrombectomy. Among the 35 patients, 21 patients had PA. Culprit plaques of patients without PA consisted of a higher percentage of the necrotic core component than those with PA (minimum lumen area [MLA]) site, 21.2+/-8.9% versus 9.9+/-9.8%, p=0.0015; entire culprit lesion, 18.9+/-6.3% versus 12.0+/-9.6%, p=0.023). In contrast, culprit plaques of patients with PA contained a higher percentage of the fibrofatty component than those without PA (MLA site, 21.0+/-12.0% versus 11.5+/-7.6%, p=0.013; entire culprit lesion, 16.8+/-7.9% versus 12.1+/-5.5%, p=0.062). There was no significant difference in quantitative parameters between the patients with and without PA.

CONCLUSIONS

Culprit plaques of patients with PA were different from those without PA. Plaque composition may play an important role in the occurrence of PA.

Characterization of hyperintense plaque with noncontrast T(1)-weighted cardiac magnetic resonance coronary plaque imaging: comparison with multislice computed tomography and intravascular ultrasound

OBJECTIVES

This study sought to characterize coronary hyperintense plaques (HIP) using noncontrast T(1)-weighted imaging (T1WI) in cardiac magnetic resonance, which was then compared with multislice computed tomography and intravascular ultrasound.

BACKGROUND

Carotid plaque components such as intraplaque hemorrhages and/or lipid-rich necrotic cores can be detected as HIP by noncontrast T1WI. Although coronary HIPs have been successfully detected using this technique, the properties of hyperintense signals in coronary plaques have not yet been systematically evaluated.

METHODS

Thirty-eight lesions from 37 patients with angina pectoris who demonstrated >70% coronary stenosis on multislice computed tomography were evaluated by noncontrast T1WI using a 1.5-T magnetic resonance imager, and 25 lesions were evaluated by intravascular ultrasound. Signal intensity of coronary plaque to cardiac muscle ratio >1.0 was defined as HIP. We divided 25 lesions into the 2 groups, according to the presence or absence of HIP: HIP (n = 18) and non-HIP (n = 7) groups.

RESULTS

In comparison with the non-HIP group, the HIP group demonstrated significantly higher coronary plaque to cardiac muscle ratio (1.7 +/- 0.7 vs. 0.9 +/- 0.1, p < 0.01), higher frequency of positive remodeling as observed by both multislice computed tomography (89% vs. 0%, p<0.0001) and intravascular ultrasound (94% vs. 14%, p < 0.001) and ultrasound attenuation (100% vs. 14.3%, p < 0.0001). The frequency of spotty calcification tended to be higher in HIP (89% vs. 50%, p = 0.079). The HIP group also exhibited a significantly lower computed tomography density (-23.2 +/- 20.7 Hounsfield units [HU] vs. 9.6 +/- 20.5 HU, p < 0.01). In addition, the incidence of transient slow-flow phenomena was significantly higher in the HIP group than in the non-HIP group (83% vs. 14%, p < 0.01).

CONCLUSIONS

The typical HIP case was associated with ultrasound attenuation, positive remodeling, remarkably low computed tomography density, and a high incidence of slow-flow phenomena. Noncontrast T1WI in cardiac magnetic resonance imaging may be useful for the assessment of coronary plaque characterization in patients with coronary artery disease.

Pulse pressure and coronary atherosclerosis in asymptomatic type 2 diabetes mellitus: a 64 channel cardiac computed tomography analysis

BACKGROUND

Identification of high risk sub-groups for early initiation of preventive medical therapy requires widespread population screening using simple, inexpensive tests. High pulse pressure has been shown to predict adverse coronary events. We examined if this correlation was related to a greater coronary plaque burden in patients with high pulse pressure using 64 channel coronary computed tomographic angiography (CCTA) in patients with type 2 diabetes mellitus.

METHODS

The study included 427 consecutive asymptomatic diabetic patients with no history of coronary disease, (age 55-74 years, 58% women), undergoing CCTA as part of a prospective outcomes study.

RESULTS

Coronary atheroma was present in 76.6% of patients, multivessel coronary atheroma in 55.1% and luminal stenosis (>or=50% of diameter) in 22.9%. Pulse pressure (adjusted for age, gender, mean blood pressure and heart rate) correlated with number of coronary arteries with atheroma (p=0.005) and with multivessel coronary atheroma (odds ratio 1.24 95%CI 1.06-1.43 for each 10 mm Hg pulse pressure, p=0.009). The correlation was independent of Framingham and United Kingdom Prospective Diabetic Study risk scores (p=0.027 and p=0.036 respectively). Adjusted pulse pressure also correlated with quartiles of coronary artery calcium score (p=0.009).

CONCLUSION

Elevated pulse pressure was a useful independent marker of presence and extent of pre-clinical coronary artery disease in an asymptomatic diabetic population.

Tissue characterization of coronary plaques: comparison of integrated backscatter intravascular ultrasound with virtual histology intravascular ultrasound

BACKGROUND

Integrated backscatter (IB) intravascular ultrasound (IVUS) and IVUS Virtual Histology (VH) have been developed for tissue characterization, but have never been compared directly. The purpose of this study was to compare the overall agreement between IB-IVUS and IVUS-VH in the tissue characterization of plaques from the same coronary arterial cross-section.

METHODS AND RESULTS

Images were acquired from 46 coronary arteries from 25 cadavers. Of a total of 392 histology/IVUS image pairs, 152 pairs were diagnosed as Stary's type III, IV, Va, Vb and Vc, and compared for IB-IVUS, IVUS-VH and histology. In the qualitative comparison, the overall agreement between histological and IB-IVUS diagnoses was higher (kappa = 0.81, 95% confidence interval (CI): 0.74-0.89) than that of the IVUS-VH diagnoses (kappa = 0.66, 95%CI: 0.56-0.75). The % fibrosis area determined by IB-IVUS was significantly correlated with the relative area of fibrosis based on histology (r = 0.67, p < 0.001). In the quantitative comparison, the overall agreement between the histological and IB-IVUS diagnoses was higher (kappa = 0.83, 95% CI: 0.75-0.91) than that of the IVUS-VH diagnoses (kappa = 0.73, 95% CI: 0.63-0.83).

CONCLUSION

Based on histology as the gold standard, IB-IVUS provided higher diagnostic accuracy than IVUS-VH for tissue characterization of coronary plaques.