Characterization of the unstable lesion by angiography, angioscopy, and intravascular ultrasound

Comprehensive analysis of clinico-pathological data reveals heterogeneous relations between atherosclerosis and cancer

AIMS

Atherosclerosis and cancer share common risk factors and involve similar molecular pathomechanisms. Most clinical and epidemiological studies show a positive correlation between atherosclerosis and smoking-related cancers and heterogeneous results for non-smoking-related cancers. However, up-to-date large-scale autopsy studies including a detailed analysis of cancer types are lacking. Therefore, we sought to investigate the relation between major cancer types and the grade of atherosclerosis in a recent well-powered autopsy cohort.

METHODS

In 2101 patients, both autopsy data and clinical data including demographics, disease groups, tumour type, cause of death and grade of atherosclerosis were reviewed and statistically analysed.

RESULTS

We found cancer in general is associated with less atherosclerosis (OR 0.60, p<0.0001). In particular, haematological neoplasm and sarcomas were associated with much less atherosclerosis (OR=0.45, p<0.0001 and OR=0.43, p=0.087), while carcinomas were associated with moderately less atherosclerosis (OR=0.72, p=0.002). Furthermore, non-smoking-related cancers were associated with much less atherosclerosis (OR=0.41, p<0.0001), while possibly smoking-related cancer and smoking-related cancer showed no significant association. In a comprehensive analysis of 21 cancer types, biliary tract cancer, lymphomas/lymphoid leukaemias and kidney cancer were associated with much less atherosclerosis (OR=0.19, p<0.0001; OR=0.41, p<0.0001; and OR=0.48, p=0.029). In an exploratory analysis of treatment strategies, we found that tumours with a recommendation of oxazaphosphorines and pyrimidine antagonist treatment were significantly associated with less atherosclerosis (OR=0.33, p=0.0068 and OR=0.58, p=0.012).

CONCLUSIONS

In conclusion, the study showed an inverse association between cancer and atherosclerosis postmortem that depends on the cancer type and suggests a possible impact of chemotherapy regimens.

The appropriateness of single page of activation of the cardiac catheterization laboratory by emergency physician for patients with suspected ST-segment elevation myocardial infarction: a cohort study

Background

The early use of reperfusion therapy has a significant effect on the prognosis of patients with ST-segment elevation myocardial infarction (STEMI), and it is recommended that emergency department (ED) physicians activate the cardiac catheterization laboratory (CCL) as soon as possible to treat these patients. The aim of this study was to examine the appropriateness of emergency physician activation of the CCL for patients with suspected STEMI. Inappropriate activations (i.e., false positive activations) were identified according to a variety of criteria.

Methods

All patients with emergency physician CCL activations between August 2009 and April 2011 were included in the study. False positive cases were defined according to ECG criteria and cardiologists' reviews of patients' initial clinical information.

Results

ED physicians used a STEMI page to activate the CCL 117 times. According to reviews by cardiologists, this activation was appropriate 89.8% of the time (in 105/117 cases). Truly unnecessary activation (i.e., cases in which STEMI was not identified by the cardiologists, no clear culprit coronary artery was present, no significant coronary artery disease and cardiac biomarkers were negative) occurred 5.1% of the time (in 6/117 cases).

Conclusions

CCL activation was appropriate for most patients and was unnecessary in a relatively small percentage of cases. This result supports the current recommendation for CCL activation by emergency physicians. Such early activation is a key strategy in the reduction of door-to-balloon time.

Assessment of atherosclerotic plaques in a rabbit model by delayed-phase contrast-enhanced CT angiography: comparison with histopathology

The aim of this study was to compare delayed-phase computed tomography angiography (CTA) attenuation values with histopathology, in ability to differentiate between fibrous and lipid-rich plaques in an experimental rabbit model. Twelve atherosclerotic rabbits underwent CTA of the abdominal aorta. The scan protocol included early-phase scans (EP), delayed scans at 90 s after contrast injection (DP(90s)), delayed scans at 10 min after contrast injection (DP(10min)), and delayed scan with saline infusion (DP(Saline)). Plaque composition was analyzed by histopathology (% of lipid-rich, fibrous and macrophage areas) and CT attenuation values in Hounsfield units. Using histopathology as the reference standard (n = 119), the overall sensitivity, specificity and accuracy of 64-slice CTA for the detection of plaques was 59, 100 and 79% for the EP scans; 88, 100 and 94% for the DP(90s) scans; 81, 100 and 90% for the DP(10min) scans; and 53, 100 and 76% for the DP(Saline) scans. CT density measurements showed a substantial overlap between fibrous and lipid-rich plaques, and poor correlations with the percentage of macrophage areas in both fibrous and lipid-rich plaques (r = 0.408, and r = 0.333). In delayed-phase 64-slice CTA, DP(90s) images have the best diagnostic performance for the detection of aortic plaques.

Quantification and characterization of obstructive coronary plaques using 64-slice computed tomography: a comparison with intravascular ultrasound

PURPOSE

The aim of this study was to determine the diagnostic accuracy of 64-slice computed tomography (CT) coronary angiography in the quantification and characterization of obstructive coronary plaques in comparison with intravascular ultrasound (IVUS).

MATERIALS AND METHODS

Thirty-nine patients were selected who underwent both CT coronary angiography (CTCA) and IVUS. For each stenotic site (n = 61), the maximum vessel cross-sectional area, lumen cross-sectional area, plaque area, and percentage of luminal obstruction were measured. Plaque composition was analyzed according to IVUS (plaque echogenicity and classified into several types: calcified, mixed, fibrous, and soft plaques) and CTCA criteria (Hounsfield units [HU]). The correlation between CTCA and IVUS measurements was determined using Pearson correlation coefficient. The statistical significance of differences in the CT densities of plaques among plaque types determined by IVUS was assessed using the Scheffe method.

RESULTS

The correlation coefficients for the measurements of the lumen, vessel, plaque area, and percentage of luminal obstruction were r = 0.712, r = 0.654, r = 0.753, and r = 0.799, respectively. The mean CT density values for soft (n = 10), fibrous (n = 11), mixed (n = 31), and calcified plaques (n = 9) were 54 +/- 13 HU, 82 +/- 17 HU, 162 +/- 57 HU, and 392 +/- 155 HU, respectively. Computed tomography density measurements were not significantly different between soft and fibrous plaques (P = 0.224).

CONCLUSIONS

Sixty-four-slice CTCA is a noninvasive modality that allows quantification of coronary artery plaques. However, reliable classification of noncalcified plaques as vulnerable or stable plaques based on CT density measurements is currently limited.

Optical coherence tomography for imaging the vulnerable plaque

While our understanding of vulnerable coronary plaque is still at an early stage, the concept that certain types of plaques predispose patients to developing an acute myocardial infarction continues to be at the forefront of cardiology research. Intracoronary optical coherence tomography (OCT) has been developed to both identify and study these lesions due to its distinct resolution advantage over other imaging modalities. We review clinical research conducted at the Massachusetts General Hospital over the past five years to develop, validate, and utilize this technology to improve our understanding of vulnerable plaque. Our results show that intracoronary OCT may be safely conducted in patients and that it provides abundant information regarding plaque microscopic morphology, which is essential to the identification and study of high-risk lesions. Even though many basic biological, clinical, and technological challenges must be addressed prior to widespread use of this technology, the unique capabilities of OCT ensure that it will have a prominent role in shaping the future of cardiology.

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.

Visualising noncalcified coronary plaques by CT

Due to a rapid improvement of the new generation submillimetre multislice CT-technology noninvasive tomographic imaging of the coronary vessel wall has become reality. First clinical studies have shown the ability in particular of 16-slice CT to determine plaque burden, plaque composition and compensatory vessel-wall remodelling. These novel findings already constitute an important step forward to assess coronary atherosclerosis noninvasively in a detailed manner which opens promising new opportunities for a better understanding and riskstratification of coronary atherosclerosis. Current limitations, mainly the insufficient accuracy to detect small lesions in distal coronary segments, might be overcome by improved spatial and temporal resolution of the new generation scanners operating with 64 and more detectors.

Markers of inflammation and multiple complex stenoses (pancoronary plaque vulnerability) in patients with non-ST segment elevation acute coronary syndromes

OBJECTIVE

To assess the relation between markers of inflammation and the presence of multiple vulnerable plaques in patients with non-ST segment elevation acute coronary syndromes.

DESIGN

Prospective cohort study of 55 patients with non-ST segment elevation acute coronary syndromes and angiographically documented coronary disease. Blood samples were obtained at study entry for the assessment of high sensitivity C reactive protein (CRP), neopterin, and neutrophil count. Coronary stenoses were assessed by quantitative computerised angiography and classified as "complex" (irregular borders, ulceration, or filling defects) or "smooth" (absence of complex features). Extent of disease was also assessed by a validated angiographic score.

RESULTS

Neutrophil count (r = 0.36, p = 0.007), CRP concentration (r = 0.33, p = 0.02), and neopterin concentration (r = 0.45, p < 0.001) correlated with the number of complex stenoses. Patients with multiple (three or more) complex stenoses, but not patients with multiple smooth lesions, had a higher neutrophil count (5.9 (1.4) x 10(9)/l v 4.8 (1.4) x 10(9)/l, p = 0.02), CRP concentration (log transformed) (1.08 (0.63) v 0.6 (0.6), p = 0.03), and neopterin concentration (log transformed) (0.94 (0.18) v 0.79 (0.15), p = 0.002). Multiple regression analysis showed that neopterin concentration (B = 4.8, 95% confidence interval (CI) 1.9 to 7.7, p = 0.002) and extent of coronary artery disease (B = 0.6, 95% CI 0.03 to 1.2, p = 0.04) were independently associated with the number of complex stenoses.

CONCLUSIONS

Acute inflammatory markers such as high neutrophil count, CRP concentration, and neopterin concentration correlate with the presence of multiple angiographically complex coronary stenoses. Neopterin concentration was a stronger predictor of multiple complex plaques than were neutrophil count and CRP concentration. These findings suggest that a relation exists between inflammation and pancoronary plaque vulnerability.

Accuracy of multidetector spiral computed tomography in identifying and differentiating the composition of coronary atherosclerotic plaques

OBJECTIVES

We evaluated the accuracy of contrast-enhanced multidetector spiral computed tomography (MDCT) for the noninvasive detection and classification of coronary plaques and compared it with intracoronary ultrasound (ICUS).

BACKGROUND

Noninvasive determination of plaque composition and plaque burden may be important to improve risk stratification and to monitor progression of coronary atherosclerosis.

METHODS

We included 46 consecutive patients with a distinctive risk profile, who were investigated by ICUS (Goldvision, 20 MHz, Jomed Inc., Rancho Cordova, California). Due to the inability to slow the heart rate below 65 beats/min (n = 7) and due to renal insufficiency (n = 2), nine of 46 consecutive patients could not be studied by MDCT (Sensation 16, Siemens, Forchheim, Germany).

RESULTS

In the remaining 37 patients, 68 vessels were investigated by ICUS, and 58 of these vessels were visualized by MDCT with image quality sufficient for analysis. In these vessels that were divided in 3-mm sections, MDCT correctly classified 62 of 80 (78%) sections containing hypoechoic plaque areas, 87 of 112 (78%) sections containing hyperechoic plaque areas, and 150 of 158 (95%) sections containing calcified plaque tissue. In 484 of 525 (92%) sections, atherosclerotic lesions were correctly excluded. The MDCT-derived density measurements within coronary lesions revealed significantly different values for hypoechoic (49 HU [Hounsfield Units] +/- 22), hyperechoic (91 HU +/- 22), and calcified plaques (391 HU +/- 156, p < 0.02).

CONCLUSIONS

This study demonstrates that, in the case of diagnostic image quality, contrast-enhanced MDCT permits an accurate identification of coronary plaques and that computed tomography density values measured within plaques reflect echogenity and plaque composition.

Deletion of the p66Shc longevity gene reduces systemic and tissue oxidative stress, vascular cell apoptosis, and early atherogenesis in mice fed a high-fat diet

Several experimental and clinical studies have shown that oxidized low-density lipoprotein and oxidation-sensitive mechanisms are central in the pathogenesis of vascular dysfunction and atherogenesis. Here, we have used p66(Shc-/-) and WT mice to investigate the effects of high-fat diet on both systemic and tissue oxidative stress and the development of early vascular lesions. To date, the p66(Shc-/-) mouse is the unique genetic model of increased resistance to oxidative stress and prolonged life span in mammals. Computer-assisted image analysis revealed that chronic 21% high-fat treatment increased the aortic cumulative early lesion area by approximately 21% in WT mice and only by 3% in p66(Shc-/-) mice. Early lesions from p66(Shc-/-) mice had less content of macrophage-derived foam cells and apoptotic vascular cells, in comparison to the WT. Furthermore, in p66(Shc-/-) mice, but not WT mice, we found a significant reduction of systemic and tissue oxidative stress (assessed by isoprostanes, plasma low-density lipoprotein oxidizability, and the formation of arterial oxidation-specific epitopes). These results support the concept that p66(Shc-/-) may play a pivotal role in controlling systemic oxidative stress and vascular diseases. Therefore, p66(Shc) might represent a molecular target for therapies against vascular diseases.

Intracoronary ultrasound in acute coronary syndromes: from characterization of vulnerable plaques to guidance of percutaneous treatment of complex stenoses

Our current knowledge on the substrate and genesis of acute coronary syndromes (ACS) results from the integration of pathological, angiographic, and intracoronary imaging techniques. To summarize briefly the current paradigm, eight differentiated stages of development of atherosclerotic lesions are currently accepted, defined not only by the cellular elements involved, but also by the appearance of sudden alterations of plaque structure and coronary thrombosis. The latter constitutes not only the dominant substrate for the most devastating manifestations of coronary artery disease, but also accelerates plaque size at a faster pace than in earlier stages. The composition of atherosclerotic plaque varies significantly along the different evolutive stages, and thus includes cellular (macrophage, smooth muscle cells) and noncellular elements (glicosaminglycan or collagen-rich cellular matrix, extracellular lipid deposits, calcification, fresh, or organized thrombus) in a varying proportion. Furthermore, a dynamic process of vessel remodeling occurs along the atherosclerotic process, resulting, in most cases, in a protective mechanism against myocardial ischemia by preserving luminal dimensions during plaque enlargement. Intravascular ultrasound (IVUS) is one of the intracoronary imaging techniques that has contributed to the understanding of these changes in man. In addition, IVUS has the potential of being a useful clinical tool for predicting the chances of future acute coronary events by identifying vulnerable plaques, of characterizing which is the culprit lesion in ACS, and in guiding revascularization procedures in the treacherous field of thrombotic coronary syndromes. In this article, we review the current evidence on the potential of IVUS imaging for fulfilling these purposes.

Angiographic correlates of a positive troponin T test in patients with unstable angina

OBJECTIVE

To study the angiographic correlates of cardiac troponin T (cTnT)-positive and -negative patients with unstable angina pectoris.

BACKGROUND

A positive cTnT test identifies a high-risk subgroup of unstable angina pectoris patients. Only the high-risk cTnT-positive patients seem to benefit from a more aggressive antithrombotic treatment regimen. The underlying coronary pathology in cTnT-positive and -negative patients that explains the predictive power of cTnT on prognosis and response to antithrombotic therapy is largely unknown.

METHODS

A total of 197 subsequently admitted patients with unstable angina pectoris underwent cTnT testing by a rapid bedside assay and early qualitative and quantitative angiography. Long-term follow-up was 12 months.

RESULTS

Patients with cTnT-positive tests revealed more critical stenoses of culprit lesions (p =.041), more severe reductions of thrombolysis in myocardial infarction flow grades (p <.037), a higher prevalence of intracoronary thrombus (p =.079), and a poorer left ventricular function (p =.047). The odds ratio of cTnT was 5.8 (p <.0001) for presence of thrombus, reduced thrombolysis in myocardial infarction flow, and/or critical stenosis (>90%), and was 3.1 (p =.005) for presence of three-vessel disease, left main disease, and/or reduced left ventricular ejection fraction. Coronary bypass grafting was more frequently performed in the cTnT-positive group. However, event-free survival was not different in our cohort characterized by a high rate of percutaneous coronary interventions.

CONCLUSIONS

A positive cTnT test in patients with unstable angina pectoris indicates presence of more severe coronary artery disease and poorer left ventricular function. This finding could explain the differences in short- and long-term outcome and treatment responses to antithrombotic regimens.