Determinants and correlates of target lesion calcium in coronary artery disease: a clinical, angiographic and intravascular ultrasound study

Intravascular ICG-enhanced NIRF-IVUS imaging to assess progressive atherosclerotic lesions in excised human coronary arteries

Indocyanine green (ICG)-enhanced intravascular near-infrared fluorescence (NIRF) imaging enhances the information obtained with intravascular ultrasound (IVUS) by visualizing pathobiological characteristics of atherosclerotic plaques. To advance our understanding of this hybrid method, we aimed to assess the potential of NIRF-IVUS to identify different stages of atheroma progression by characterizing ICG uptake in human pathological specimens. After excision, 15 human coronary specimens from 13 adult patients were ICG-perfused and imaged with NIRF-IVUS. All specimens were then histopathologically and immunohistochemically assessed. NIRF-IVUS imaging revealed colocalization of ICG-deposition to plaque areas of lipid accumulation, endothelial disruption, neovascularization and inflammation. Moreover, ICG concentrations were significantly higher in advanced coronary artery disease stages (p < 0.05) and correlated significantly to plaque macrophage burden (r = 0.67). Current intravascular methods fail to detect plaque biology. Thus, we demonstrate how human coronary atheroma stage can be assessed based on pathobiological characteristics uniquely captured by ICG-enhanced intravascular NIRF.

Ostial right coronary artery lesion morphology and outcomes after treatment with drug-eluting stents

BACKGROUND

Outcomes after percutaneous coronary intervention (PCI) for de novo ostial right coronary artery (RCA) lesions are poor.

AIMS

We used intravascular ultrasound (IVUS) to clarify the morphological patterns of de novo ostial RCA lesions and their associated clinical outcome.

METHODS

Among 5,102 RCA IVUS studies, 170 de novo ostial RCA stenoses (within 3 mm from the aorto-ostium) were identified. These were classified as 1) isolated ostial lesions (no disease extending beyond 10 mm from the ostium and without a calcified nodule [CN]); 2) ostial CN, typically with diffuse disease (disease extending beyond 10 mm); and 3) ostial lesions with diffuse disease but without a CN. The primary outcome was target lesion failure (TLF: cardiac death, target vessel myocardial infarction, definite stent thrombosis, and ischaemia-driven target lesion revascularisation).

RESULTS

The prevalence of an isolated ostial lesion was 11.8% (n=20), 47.6% (n=81) were ostial CN, and 40.6% (n=69) were ostial lesions with diffuse disease. Compared to ostial lesions with diffuse disease, isolated lesions were more common in women (75.0% vs 42.0%; p=0.01), and CN were associated with older age (median [first, third quartile] 76 [70, 83] vs 69 [63, 81] years old; p=0.002). The Kaplan-Meier rate of TLF at 2 years was significantly higher in patients with CN (21.6%) compared to diffuse lesions (8.2%) (p=0.04), and patients with isolated lesions had no events. A multivariable Cox proportional hazard model revealed that CN were significantly associated with TLF (hazard ratio 6.63, 95% confidence interval: 1.28-34.3; p=0.02).

CONCLUSIONS

Ostial RCA lesions have specific morphologies - detectable by IVUS - that may be associated with long-term clinical outcomes.

Beyond the Basics: Unraveling the Complexity of Coronary Artery Calcification

Coronary artery calcification (CAC) is mainly associated with coronary atherosclerosis, which is an indicator of coronary artery disease (CAD). CAC refers to the accumulation of calcium phosphate deposits, classified as micro- or macrocalcifications, that lead to the hardening and narrowing of the coronary arteries. CAC is a strong predictor of future cardiovascular events, such as myocardial infarction and sudden death. Our narrative review focuses on the pathophysiology of CAC, exploring its link to plaque vulnerability, genetic factors, and how race and sex can affect the condition. We also examined the connection between the gut microbiome and CAC, and the impact of genetic variants on the cellular processes involved in vascular calcification and atherogenesis. We aimed to thoroughly analyze the existing literature to improve our understanding of CAC and its potential clinical and therapeutic implications.

Coronary artery calcification and plaque stability： an optical coherence tomography study

Background

Coronary artery calcification (CAC), a surrogate of atherosclerosis, is related to stent underexpansion and adverse cardiac events. However, the effect of CAC on plaque stability is still controversial and the morphological significance of CAC has yet to be elucidated.

Methods

A retrospective series of 419 patients with acute coronary syndrome (ACS) who underwent optical coherence tomography (OCT) were enrolled. Patients were classified into three groups based on the calcification size in culprit plaques and the features of the culprit and non-culprit plaques among these groups were compared. Logistic regression was used to analyze independent risk factors for culprit plaque rupture and the nonlinear relationship between calcification parameters and culprit plaque rupture. Furthermore, we compared the detailed calcification parameters of different kinds of plaques.

Results

A total of 419 culprit plaques and 364 non-culprit plaques were identified. The incidence of calcification was 53.9 % in culprit plaques and 50.3 % in non-culprit plaques. Compared with culprit plaques without calcification, plaque rupture, macrophages and cholesterol crystals were more frequently observed in the spotty calcification group, and the lipid length was longer; the incidence of macrophages and cholesterol crystals was higher in the macrocalcification group. Calcification tended to be smaller in ruptured plaques than in non-ruptured plaques. Moreover, the arc and length of calcification were greater in culprit plaques than in non-culprit plaques.

Conclusions

Vulnerable features were more frequently observed in culprit plaques with spotty calcification, whereas the presence of macrocalcification calcifications did not significantly increase plaque vulnerability. Calcification tends to be larger in culprit plaques than in non-culprit plaques.

Cationic proteins from eosinophils bind bone morphogenetic protein receptors promoting vascular calcification and atherogenesis

AIMS

Blood eosinophil count and eosinophil cationic protein (ECP) concentration are risk factors of cardiovascular diseases. This study tested whether and how eosinophils and ECP contribute to vascular calcification and atherogenesis.

METHODS AND RESULTS

Immunostaining revealed eosinophil accumulation in human and mouse atherosclerotic lesions. Eosinophil deficiency in ΔdblGATA mice slowed atherogenesis with increased lesion smooth muscle cell (SMC) content and reduced calcification. This protection in ΔdblGATA mice was muted when mice received donor eosinophils from wild-type (WT), Il4-/-, and Il13-/- mice or mouse eosinophil-associated-ribonuclease-1 (mEar1), a murine homologue of ECP. Eosinophils or mEar1 but not interleukin (IL) 4 or IL13 increased the calcification of SMC from WT mice but not those from Runt-related transcription factor-2 (Runx2) knockout mice. Immunoblot analyses showed that eosinophils and mEar1 activated Smad-1/5/8 but did not affect Smad-2/3 activation or expression of bone morphogenetic protein receptors (BMPR-1A/1B/2) or transforming growth factor (TGF)-β receptors (TGFBR1/2) in SMC from WT and Runx2 knockout mice. Immunoprecipitation showed that mEar1 formed immune complexes with BMPR-1A/1B but not TGFBR1/2. Immunofluorescence double-staining, ligand binding, and Scatchard plot analysis demonstrated that mEar1 bound to BMPR-1A and BMPR-1B with similar affinity. Likewise, human ECP and eosinophil-derived neurotoxin (EDN) also bound to BMPR-1A/1B on human vascular SMC and promoted SMC osteogenic differentiation. In a cohort of 5864 men from the Danish Cardiovascular Screening trial and its subpopulation of 394 participants, blood eosinophil counts and ECP levels correlated with the calcification scores of different arterial segments from coronary arteries to iliac arteries.

CONCLUSION

Eosinophils release cationic proteins that can promote SMC calcification and atherogenesis using the BMPR-1A/1B-Smad-1/5/8-Runx2 signalling pathway.

Non-traditional tools for predicting coronary artery disease

Background

The traditional coronary calcium score (CCS) is a time-tested tool for the evaluation of coronary atherosclerosis and predictor of future cardiovascular events. Non-traditional tools can also have a value in predicting and detecting subclinical coronary artery disease (CAD).

Methods

We studied the role of CCS, the traditional CAD risk predictor, and the less-recognized, non-traditional risk factors, i.e. epicardial fat volume (EFV) and thoracic extracoronary calcium (ECC), to assess the degree of subclinical CAD. In this cross-sectional observational study, we included 950 Indian patients (suspected to have CAD). Coronary computed tomography angiography was performed. Estimation of CCS, EFV and thoracic ECC was done.

Results

A CCS of 0 was seen in 583 patients (61.4%). Of these, 492 patients had normal coronary angiogram but 91 patients had CAD. The median values of EFV were statistically significantly higher in the ‘CAD present and CCS 0’ group compared to the ‘CAD absent and CCS 0’ group (p<0.001). The presence of thoracic ECC involving at least a single site was seen in only 6 of these 91 patients. When both EFV and CCS were considered together for the detection of CAD, the sensitivity and negative predictive value (NPV) were improved compared to either of these in isolation. When ECC was taken together with CCS and EFV, no further improvement in sensitivity or NPV was observed.

Conclusion

The combined use of traditional CCS along with non-traditional EFV may guide us in better profiling cardiovascular risk and supplement the various traditional cardiovascular risk factors/scores.

Obstructive coronary artery disease in symptomatic diabetics with zero coronary calcium score: are we missing something?

BACKGROUND

Prevalence and severity of coronary artery disease (CAD) in symptomatic patients with zero coronary artery calcium score (CACS) are unclear, particularly in regard to the diabetic population, which represents, per se, a subgroup at increased cardiovascular risk. The aim of this study was to investigate the prevalence and severity of CAD by coronary computed tomography angiography (CCTA) in a symptomatic diabetic cohort with zero CACS.

METHODS

All consecutive symptomatic diabetics referred for CAD suspicion were included in this study. All subjects underwent a noncontrast coronary artery calcium scan followed by CCTA. CACS was quantified using the Agatston method. CAD was defined as a total plaque score (TPS) greater than zero. Obstructive and severe obstructive CAD were defined respectively as luminal stenosis >50% and >70% in at least one coronary segment.

RESULTS

We identified 1722 symptomatic diabetics (mean age 62.5 ± 12.9 years, 62% men). One hundred and eleven subjects had zero CACS and TPS >0 (mean age was 49.5 ± 14.8, 58% women, 56% Hispanics). Sixty-five patients (58.5%) had one-vessel disease, followed by 30 (27%) with two-vessel disease and 14 (12.6%) with ≥ three-vessel disease. Obstructive CAD was found in 11 subjects and, among these, three were categorized as severe obstructive CAD.

CONCLUSION

In symptomatic diabetic patients with zero CACS, CAD, including obstructive disease, can still occur and is predominant in middle-aged adults, women and Hispanics. In symptomatic diabetics CCTA is a critical step for accurate risk stratification even when CACS would have placed some of these individuals in a lower-risk category.

Coronary Computed Tomography Angiography Analysis of Calcium Content to Identify Non-culprit Vulnerable Plaques in Patients With Acute Coronary Syndrome

Background

Aside from the culprit plaque, the presence of vulnerable plaques in patients with acute coronary syndrome (ACS) may be associated with future cardiac events. A link between calcification and plaque rupture has been previously described.

Aim

To assess whether analysis of the calcium component of coronary plaques using CT angiography, coronary computed tomographic angiography (CCTA) can help to detect additional vulnerable plaques in patients with non-ST elevation myocardial infarction (NSTEMI).

Materials And Methods

Cross sectional study of consecutive patients referred for NSTEMI from 30 July to 30 August 2018 with CCTA performed before coronary angiography with systematic optical coherence tomography (OCT) analysis of all coronary arteries within 24 h of clinical onset of NSTEMI. Three types of plaques were defined: culprit plaques defined by angiography (vulnerable culprit plaques–VCP) – plaques with a fibrous cap thickness < 65 microns or thrombus in OCT (vulnerable non-culprit plaque–VNCP) – plaques with a fibrous cap thickness ≥ 65 microns in OCT (stable plaque–SP).

Results

A total of 134 calcified plaques were identified in 29 patients (73% male, 59 ± 14 years) with 29(22%) VCP, 28(21%) VNCP and 77(57%) SP. Using CCTA analysis of the calcium component, factors associated with vulnerable plaques were longer calcification length, larger calcification volume, lower calcium mass, higher Agatston score plaque-specific (ASp), presence of spotty calcifications and an intimal position in the wall. In multivariate analysis, ASp, calcification length and spotty calcifications were independently associated to vulnerable plaques. There was no difference between VCP and VNCP.

Conclusions

CCTA analysis of calcium component of the plaque could help to identify additional vulnerable plaques in NSTEMI patients.

Clinical determinants of coronary artery disease burden and vulnerability using optical coherence tomography co-registered with intravascular ultrasound

OBJECTIVES

We investigated clinical determinants of disease burden and vulnerability using optical coherence tomography (OCT) co-registered with intravascular ultrasound (IVUS) in a large cohort of patients.

METHODS

A total of 704 patients [44.5% with acute coronary syndromes (ACS)] underwent coronary intervention. IVUS plaque burden and OCT lipid, macrophage and calcium indices and the presence of thrombus, plaque rupture and thin-cap fibroatheroma (TCFA) were analyzed.

RESULTS

Median patient age was 66 years with 81.8% men, 34.4% with diabetes mellitus and 15.5% with preadmission statins. Median lesion length was 25.7 mm, and 33.0% had a TCFA. Adjusted models indicated (1) older patient age was related to more calcium, but fewer macrophages; (2) men were related to more thrombus with plaque rupture while women had more thrombus without plaque rupture; (3) ACS presentation was related to morphological acute thrombotic events (more thrombus with/without rupture) and plaque vulnerability (more TCFA, more lipid and macrophages and larger plaque burden); (4) diabetes mellitus was related to a greater atherosclerotic disease burden (more lipid and calcium and larger plaque burden) and more thrombus without rupture; (5) hypertension was related to more macrophages; (6) current smoking was related to less calcium; and (7) renal insufficiency and preadmission statin therapy were not independently associated with IVUS or OCT plaque morphology.

CONCLUSION

Patient characteristics, especially diabetes mellitus and aging, affect underlying atherosclerotic burden, among which a greater lipidic burden along with sex differences influence local thrombotic morphology that affects clinical presentation.

Current and Future Applications of Artificial Intelligence in Coronary Artery Disease

Cardiovascular diseases (CVDs) carry significant morbidity and mortality and are associated with substantial economic burden on healthcare systems around the world. Coronary artery disease, as one disease entity under the CVDs umbrella, had a prevalence of 7.2% among adults in the United States and incurred a financial burden of 360 billion US dollars in the years 2016–2017. The introduction of artificial intelligence (AI) and machine learning over the last two decades has unlocked new dimensions in the field of cardiovascular medicine. From automatic interpretations of heart rhythm disorders via smartwatches, to assisting in complex decision-making, AI has quickly expanded its realms in medicine and has demonstrated itself as a promising tool in helping clinicians guide treatment decisions. Understanding complex genetic interactions and developing clinical risk prediction models, advanced cardiac imaging, and improving mortality outcomes are just a few areas where AI has been applied in the domain of coronary artery disease. Through this review, we sought to summarize the advances in AI relating to coronary artery disease, current limitations, and future perspectives.

Automatic detection of vessel structure by deep learning using intravascular ultrasound images of the coronary arteries

Intravascular ultrasound (IVUS) is a diagnostic modality used during percutaneous coronary intervention. However, specialist skills are required to interpret IVUS images. To address this issue, we developed a new artificial intelligence (AI) program that categorizes vessel components, including calcification and stents, seen in IVUS images of complex lesions. When developing our AI using U-Net, IVUS images were taken from patients with angina pectoris and were manually segmented into the following categories: lumen area, medial plus plaque area, calcification, and stent. To evaluate our AI's performance, we calculated the classification accuracy of vessel components in IVUS images of vessels with clinically significantly narrowed lumina (< 4 mm2) and those with severe calcification. Additionally, we assessed the correlation between lumen areas in manually-labeled ground truth images and those in AI-predicted images, the mean intersection over union (IoU) of a test set, and the recall score for detecting stent struts in each IVUS image in which a stent was present in the test set. Among 3738 labeled images, 323 were randomly selected for use as a test set. The remaining 3415 images were used for training. The classification accuracies for vessels with significantly narrowed lumina and those with severe calcification were 0.97 and 0.98, respectively. Additionally, there was a significant correlation in the lumen area between the ground truth images and the predicted images (ρ = 0.97, R2 = 0.97, p < 0.001). However, the mean IoU of the test set was 0.66 and the recall score for detecting stent struts was 0.64. Our AI program accurately classified vessels requiring treatment and vessel components, except for stents in IVUS images of complex lesions. AI may be a powerful tool for assisting in the interpretation of IVUS imaging and could promote the popularization of IVUS-guided percutaneous coronary intervention in a clinical setting.

Coronary Computer Tomography Angiography in 2021-Acquisition Protocols, Tips and Tricks and Heading beyond the Possible

Recent technological advances, together with an increasing body of evidence from randomized trials, have placed coronary computer tomography angiography (CCTA) in the center of the diagnostic workup of patients with coronary artery disease. The method was proven reliable in the diagnosis of relevant coronary artery stenosis. Furthermore, it can identify different stages of the atherosclerotic process, including early atherosclerotic changes of the coronary vessel wall, a quality not met by other non-invasive tests. In addition, newer computational software can measure the hemodynamic relevance (fractional flow reserve) of a certain stenosis. In addition, if required, information related to cardiac and valvular function can be provided with specific protocols. Importantly, recent trials have highlighted the prognostic relevance of CCTA in patients with coronary artery disease, which helped establishing CCTA as the first-line method for the diagnostic work-up of such patients in current guidelines. All this can be gathered in one relatively fast examination with minimal discomfort for the patient and, with newer machines, with very low radiation exposure. Herein, we provide an overview of the current technical aspects, indications, pitfalls, and new horizons with CCTA, providing examples from our own clinical practice.

Intravascular ultrasound-based deep learning for plaque characterization in coronary artery disease

BACKGROUND AND AIMS

Although plaque characterization by intravascular ultrasound (IVUS) is important for risk stratification, frame-by-frame analysis of a whole vascular segment is time-consuming. The aim was to develop IVUS-based algorithms for classifying attenuation and calcified plaques.

METHODS

IVUS image sets of 598 coronary arteries from 598 patients were randomized into training and test sets with 5:1 ratio. Each IVUS frame at a 0.4-mm interval was circumferentially labeled as one of three classes: attenuated plaque, calcified plaque, or plaque without attenuation or calcification. The model was trained on multi-class classification with 5-fold cross validation. By converting from Cartesian to polar coordinate images, the class corresponding to each array from 0 to 360° was plotted.

RESULTS

At the angle-level, Dice similarity coefficients for identifying calcification vs. attenuation vs. none by using ensemble model were 0.79, 0.74 and 0.99, respectively. Also, the maximal accuracy was 98% to classify those groups in the test set. At the frame-level, the model identified the presence of attenuation with 80% sensitivity, 96% specificity, and 93% overall accuracy, and the presence of calcium with 86% sensitivity, 97% specificity, and 96% overall accuracy. In the per-vessel analysis, the attenuation and calcification burden index closely correlated with human measurements (r = 0.89 and r = 0.95, respectively), as did the maximal attenuation and calcification burden index over 4 mm (r = 0.82 and r = 0.91, respectively). The inference times were 0.05 s per frame and 7.8 s per vessel.

CONCLUSIONS

Our deep learning algorithms for plaque characterization may assist clinicians in recognizing high-risk coronary lesions.

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

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

Resting Pd/Pa correlates with fractional flow reserve but not angiographic severity in calcified coronary arteries

OBJECTIVE

Study the effect of coronary artery calcium (CAC) on resting coronary physiological indices.

BACKGROUND

Prior studies found no correlation between angiographic stenosis and fractional flow reserve (FFR) in heavily calcified arteries.

METHODS

Two hundred consecutive patients undergoing whole-cycle resting Pd/Pa and FFR evaluation of a single lesion of intermediate severity (40-80%) had CAC quantified based upon radiopacities at the site of the stenosis, where 0 = none or mild calcium, 1 = moderate calcium, and 2 = severe calcium.

RESULTS

Mean age was 61 ± 11 years and 34% were female. The mean degree of stenosis, FFR, and resting Pd/Pa were 60 ± 12%, 0.83 ± 0.08, and 0.93 ± 0.05, respectively. Resting Pd/Pa correlated with degree of angiographic diameter stenosis (DS) as determined by quantitative coronary angiography (QCA) or visual estimation in arteries with calcium score of 0 or 1, but there was no correlation in severely calcified arteries. The diagnostic accuracy of DS ≥70% by QCA to predict hemodynamic significance was 68% with calcium scores of 0/1, but only 43% with calcium score = 2. Resting Pd/Pa was highly correlated with FFR irrespective of the degree of CAC (R² = 0.68, p < .001) and the sensitivity of resting Pd/Pa ≤0.91 for predicting an FFR ≤0.80 was 0.67 in arteries with calcium scores of 0 or 1 and 0.69 in arteries with a calcium score of 2.

CONCLUSIONS

There was no correlation between angiographic stenosis and either resting Pd/Pa or FFR in heavily calcified coronary artery lesions.

Calcium deposition within coronary atherosclerotic lesion: Implications for plaque stability

Atherosclerotic lesion progression is associated with intimal calcification. The earliest lesion that shows calcification is pathologic intimal thickening in which calcifications appear as microcalcifications that vary in size from <0.5 to 15 μm. The calcifications become larger as plaques progress, becoming punctate (>15 μm to 1 mm in diameter), fragmented (>1 mm), and eventually sheet-like calcification (>3 mm). When stratified by plaque type, maximum calcifications are observed in fibrocalcific plaques, followed by healed plaque ruptures. Lesions of acute thrombi, i.e., plaque rupture and erosions, which are the most frequent causes of acute coronary syndromes, show much less calcification than stable fibrocalcific plaques. Conversely, a calcified nodule, the least common lesion of acute thrombosis, occurs in highly calcified lesions. Pro-inflammatory cytokines observed in unstable plaques may provoke an early phase of osteogenic differentiation of smooth muscle cells (SMCs), a release of calcifying extracellular matrix vesicles, and/or induce apoptosis of macrophages and SMCs, which also calcify. Recent pathologic and imaging based studies indicate that lesions with dense calcifications are more likely to be stable plaques (fibrocalcific plaques), while micro, punctate, or fragmented calcifications are associated with either early stage plaques or unstable lesions (plaque rupture or erosion). Clinical non-invasive computed tomography (CT) studies show that the greater the calcium score, the higher the likelihood of patients developing future acute coronary events. This appears contradictory with the findings from pathologic autopsy studies. However, CT analysis of calcium subtypes is limited by resolution and blooming artifacts. Thus, areas of heavy calcification may not be the cause of future events as pathologic studies suggest. Rather, calcium may be an overall marker for the extent of disease. These types of discrepancies can perhaps be resolved by invasive or non-invasive high resolution imaging studies carried out at intervals in patients who present with acute coronary syndromes versus stable angina patients. Coronary calcium burden is greater in stable plaques than unstable plaques and there is a negative correlation between necrotic core area and area of calcification. Recent clinical studies have demonstrated that statins can reduce plaque burden by demonstrating a reduction in percent and total atheroma volume. However, calcification volume increases. In summary, pathologic studies show that sheet calcification is highly prevalent in stable plaques, while microcalcifications, punctate, and fragmented calcifications are more frequent in unstable lesions. Both pathologic and detailed analysis of imaging studies in living patients can resolve some of the controversies in our understanding of coronary calcification.

Intravascular Imaging to Guide Lithotripsy in Concentric and Eccentric Calcific Coronary Lesions

BACKGROUND

Calcified coronary lesions still represent a challenge for coronary angioplasty, with sub-optimal acute PCI results causing more frequent late stent failure.

PURPOSE

The study aimed at the evaluation of the immediate procedural outcome in a real-world consecutive population of a selective use of lithotripsy based on the intravascular imaging assessment with IVUS or OCT.

METHODS AND RESULTS

Thirty-one calcified stenoses (28 patients) out of a total of 455 lesions (370 patients) treated between November 2018 and May 2019 received IVL under intravascular imaging guidance. The majority of the IVL lesions had angiographically severe calcifications and were selected after intravascular imaging. A smaller group was identified by poor expansion after high-pressure balloon dilatation, in one case despite preliminary small burr Rotablation. After IVL, when OCT was performed calcium fractures were observed in 71% of cases. After OCT/IVUS guided stent optimization a satisfactory lumen enlargement (minimal stent area 7.09 ± 2.77 mm²) was observed with good stent expansion (residual area stenosis<20% in 29 lesions, 93.5%) Peri-procedural complications were limited to one dissection at the distal edge requiring an additional stent and 3 peri-procedural myocardial infarctions. There were no periprocedural coronary perforations or pericardial effusions, and no in-hospital or 30 days stent thrombosis. When patients were divided into two subgroups according to a calcium arc ≤180° (Group A: 10 lesions, calcium arc 140 ± 24°; Group B: 21 lesions, calcium arc 289 ± 53°), at OCT Group B presented also a higher number of calcium fractures post IVL than group A (group A: 38% vs group B: 92%, p = 0.03). The in-stent minimum lumen diameter (MSD), the in stent minimal lumen area (MSA) and the acute gain, however, were similar between the two groups (acute gain group A: 1.22 ± 0.29 mm; group B: 1.31 ± 0.52 mm, p = 0.63).

CONCLUSIONS

A standardized algorithm applying intravascular imaging guidance of IVL facilitated second generation DES expansion delivers excellent immediate lumen expansion and patient outcome, both in concentric and eccentric calcifications.

Association of mineral content outside of bone with coronary artery calcium and 1-year cardiovascular prognosis in maintenance hemodialysis patients

Coronary artery calcifications (CACs) are common among maintenance hemodialysis (MHD) patients and associated with increased morbidity and mortality due to cardiovascular events. The insight into chronic kidney disease‐mineral and bone disorder (CKD‐MBD) established a correlation between dysregulated mineral metabolism and CACs. This study aimed to identify the association of mineral content outside of bone (MCOB) with CACs and cardiovascular events in MHD patients. In the pilot prospective study with no intervention, patients underwent body composition assessment by body composition monitor after hemodialysis and computed tomography examination using the Agatston scoring method simultaneously within a week. The primary end point included cardiovascular events and cardiovascular death. Correlations and receiver operating characteristic analysis elucidated the associations of MCOB with CACs; multivariate analysis assessed the cardiovascular risk for groups with different MCOB. One hundred three eligible patients with an average age of 48 (35‐63) years old were enrolled and followed up to 12 (11‐12.5) months, among which 52.4% had detectable CACs at baseline. MCOB showed an inverse correlation with Agatston score and significantly discriminated the patients with Agatston score > 0 (AUC = 0.737; P < 0.001) and 400 (AUC = 0.733; P < 0.001). MCOB ≤ 9.2657 mg/kg was an independent risk factor for CACs (OR = 4.853; P = 0.044) and strong predictor for cardiovascular morbidity and mortality (HR = 10.108; P = 0.042), as well as rehospitalization (HR = 2.689; P = 0.004). MCOB inversely correlated with the presence and extent of CACs, and could discriminate Agatston score > 0 and 400, which also presented as an independent indicator for CKD‐MBD and 1‐year cardiovascular prognosis in adult MHD patients. Additional studies are required for identifying this issue.

Relationship between left main and left anterior descending arteries bifurcation angle and coronary artery calcium score in chronic kidney disease: A 3-dimensional analysis of coronary computed tomography

Background

A high coronary artery calcium score (CACS) predicts a poor prognosis in patients with coronary artery disease. We examined the relationship between the bifurcation angle and the CACS of the left main (LM) and left anterior descending (LAD) arteries in patients suffering from chronic kidney disease (CKD).

Methods

We analyzed the data of 121 patients who underwent coronary computed tomography between October 2014 and June 2015 and whose estimated glomerular filtration rate (eGFR) was <60 ml/min/1.73 m². The LM-LAD bifurcation angle was measured by 3-dimensional coronary computed tomography. The CACS of the LM-LAD arteries was also calculated. We excluded stent recipients and patient who had undergone coronary artery bypass graft surgery.

Results

In the overall sample, the mean ± standard deviation (range) LM-LAD bifurcation angle was 35.9 ± 11.4° (6.8–79.4°) and mean CACS was 227 ± 351 (0 to 1,695). The mean LM-LAD arteries angle was 40.3° ± 10.0° in 39 patients whose CACS was ≥200, versus 33.8° ± 11.6° in 82 patients with CACS <200 (p = 0.003). A weak, but positive correlation (r = 0.269, p = 0.003) was observed between the LM-LAD arteries angle and CACS of the LM-LAD arteries. By multiple variable analysis, hemoglobin A1c, triglycerides, eGFR and the LM-LAD arteries angle were independent predictors of a high CACS of the LM-LAD arteries.

Conclusion

In patients with CKD, a wide LM-LAD arteries angle was associated with a high CACS of the LM-LAD arteries. The prognostic value of this observation warrants further evaluation.

MicroRNA 8059 as a marker for the presence and extent of coronary artery calcification

Objective

MicroRNAs (miRNAs) may serve as potential biomarkers in a variety of pathologies. The aim of this study was to determine whether miRNAs could serve as blood-based markers of isolated coronary artery calcification (CAC) defined as CAC in the absence of an underlying metabolic abnormality.

Methods

24 age-matched and sex-matched patients who had been referred for elective CT coronary calcium score and angiography as part of investigation for cardiac chest pain were recruited. Peripheral venesection was performed and an Agatston calcium score was derived from the CT coronary angiogram using default software. RNA was extracted using the LeukoLOCK Total RNA Isolation System for Toray's microarray analysis and quantitative reverse transcription PCR (qRT-PCR).

Results

The patients were well matched for age, sex and conventional risk factors for coronary artery disease. Microarray analysis identified lower expression of miRNA-138-2-3p, miRNA-1181, miRNA-6816-3p and miRNA-8059 in patients with coronary artery calcium score (CACS)=0 vs CACS>100. qRT-PCR confirmed significant downregulation of miRNA-8059 in patients with CACS>100 (CACS=0 vs CACS>100; P=0.03).

Conclusion

miRNA-8059 may serve as a peripheral blood-based biomarker for the presence of CAC, as well as provide a platform for studying the pathophysiological basis of isolated CAC.

Trial registration number

NCT01992848; Results.

Features and Outcomes of Patients with Calcified Nodules at Culprit Lesions of Acute Coronary Syndrome: An Optical Coherence Tomography Study

Objectives: We sought to clarify clinical features and outcomes related to calcified nodules (CN) compared with plaque rupture (PR) and plaque erosion (PE) detected by optical coherence tomography (OCT) at the culprit lesions in patients with acute coronary syndrome (ACS). Methods: Based on OCT findings for culprit lesion plaque morphologies, ACS patients with analyzable OCT images (n = 362) were classified as CN, PR, PE, and other. Results: The prevalence of CN, PR, and PE was 6% (n = 21), 45% (n = 163), and 41% (n = 149), respectively. Patients with CN were older (median 71 vs. 65 years, p = 0.03) and more diabetic (71 vs. 35%, p = 0.002) than those without CN. In OCT findings, the distal reference lumen cross-sectional area (median 4.2 vs. 5.2 mm2, p = 0.048) and the postintervention minimum lumen cross-sectional area (median 4.5 vs. 5.3 mm2, p = 0.04) were smaller in lesions with CN than in those without. Kaplan-Meier estimate survival curves showed that the 500-day survival without target lesion revascularization (TLR) was lower (p = 0.011) for patients with CN (72.9%) than for those with PR (89.3%) or PE (94.8%). Conclusions: ACS patients with CN at the culprit lesion had more TLR compared to those with PR or PE.

Comparative analysis of high-sensitivity cardiac troponin I and T for their association with coronary computed tomography-assessed calcium scoring represented by the Agatston score

Background

This study evaluates the association between high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) and coronary calcium concentration (CAC) detected by coronary computed tomography (CCT) and evaluated with the Agatston score in patients with suspected coronary artery disease (CAD).

Methods

Patients undergoing CCT during routine clinical care were enrolled prospectively. CCT was indicated for patients with a low to intermediate pretest probability for CAD. Within 24 h of CCT examination, peripheral blood samples were taken to measure cardiac biomarkers hs-cTnI and hs-cTnT.

Results

A total of 76 patients were enrolled including 38% without detectable CAC, 36% with an Agatston score from 1 to 100, 17% from 101 to 400, and 9% with values ≥ 400. hs-cTnI was increasing alongside Agatston score and was able to differentiate between different groups of Agatston scores. Both hs-cTn discriminated values greater than 100 (hs-cTnI, AUC = 0.663; p = 0.032; hs-cTnT, AUC = 0.650; p = 0.048). In univariate and multivariate logistic regression models, hs-cTnT and hs-cTnI were significantly associated with increased Agatston scores. Patients with hs-cTnT ≥ 0.02 µg/l and hs-cTnI ≥ 5.5 ng/l were more likely to reveal values ≥ 400 (hs-cTnT; OR = 13.4; 95% CI 1.545–116.233; p = 0.019; hs-cTnI; OR = 8.8; 95% CI 1.183–65.475; p = 0.034).

Conclusion

The present study shows that the Agatston score was significantly correlated with hs cardiac troponins, both in univariable and multivariable linear regression models. Hs-cTnI is able to discriminate between different Agatston values. The present results might reveal potential cut-off values for hs cardiac troponins regarding different Agatston values.

Trial registration Cardiovascular Imaging and Biomarker Analyses (CIBER), NCT03074253 https://clinicaltrials.gov/ct2/show/record/NCT03074253

Calcifying Matrix Vesicles and Atherosclerosis

Artery calcification is a well-recognized predictor of late atherosclerotic complications. In the intima media, calcification starts with apoptosis of vascular smooth muscle cells (VSMCs) and the release of calcifying matrix vesicles with diameter of 0.5–15 μm that can be observed microscopically. In complicated plaques, calcification is generally less frequent. Calcifying vesicles are released by proatherosclerotic VSMCs into the collagen-rich matrix. The vesicles can penetrate into the intima media and protrude into the arterial lumen and thereby may represent a potential cause of atherothrombosis. In calcified fibrolipid plaques, the rate of calcification is increased but is followed with healing of a lesion rupture and exhibited by further erosion and/or intimal thickening. Generally, calcification directly correlates with the apoptosis of VSMCs and macrophages accompanied by the release of osteogenic matrix vesicles. This is a hallmark of atherosclerosis-related apoptosis of VSMCs that is commonly released in plaque stabilization.

Web-based accurate measurements of carotid lumen diameter and stenosis severity: An ultrasound-based clinical tool for stroke risk assessment during multicenter clinical trials

BACKGROUND

This pilot study presents a completely automated, novel, smart, cloud-based, point-of-care system for (a) carotid lumen diameter (LD); (b) stenosis severity index (SSI) and (c) total lumen area (TLA) measurement using B-mode ultrasound. The proposed system was (i) validated against manual reading taken by the Neurologist and (ii) benchmarked against the commercially available system.

METHOD

One hundred patients (73 M/27 F, mean age: 68 ± 11 years), institutional review board approved, written informed consent, consisted of left/right common carotid artery (200 ultrasound scans) were acquired using a 7.5-MHz linear transducer.

RESULTS

The measured mean LD for left and right carotids were (in mm): (i) for proposed system (6.49 ± 1.77, 6.66 ± 1.70); and (ii) for manual (6.29 ± 1.79, 6.45 ± 1.63), respectively and coefficient of correlation between cloud-based automated against manual were 0.98 (P < 0.0001) and 0.99 (P < 0.0001), respectively. The corresponding TLA error, Precision-of-Merit, and Figure-of-Merit when measured against the manual were: 4.56 ± 3.54%, 96.18 ± 3.21%, and 96.85%, respectively. The AUC for the receiving operating characteristics for the cloud-based system was: 1.0. Four statistical tests such as: Two-tailed z-test, Mann-Whitney test, Kolmogorov-Smirnov (KS) and one-way ANOVA were performed to demonstrate consistency and reliability.

CONCLUSIONS

The proposed system is reliable, accurate, fast, completely automated, anytime-anywhere solution for multi-center clinical trials and routine vascular screening.

Carotid plaque instability is not related to quantity but to elemental composition of calcification

BACKGROUND AND AIMS

Recent studies highlighted the role of calcification processes in the clinical progression of chronic cardiovascular diseases. In this study we investigated the relationship between the chemical composition of calcification and atherosclerotic plaque stability in carotid arteries.

METHODS AND RESULTS

To this end, we characterized the calcification on 229 carotid plaques, by morphology, immunohistochemistry, transmission electron microscopy and energy dispersive X-ray microanalysis. Plaques were classified into two categories: unstable and stable. No significant differences were found in the incidence of the various risk factors between patients with and without carotid calcification, with the exception of diabetes. The energy dispersive X-ray microanalysis allowed us to identify two types of calcium salts in the atheromatous plaques, hydroxyapatite (HA) and calcium oxalate (CO). Our results showed that calcification is a common finding in carotid plaques, being present in 77.3% of cases, and the amount of calcium is not a factor of vulnerability. Noteworthy, we observed an association between HA calcification and unstable plaques. On the contrary, CO calcifications were mainly detected in stable plaques.

CONCLUSIONS

The presence of different types of calcification in atheromatous plaques may open new perspectives in understanding the molecular mechanisms of atheroma formation and plaque instability.

Does calcium burden impact culprit lesion morphology and clinical results? An ADAPT-DES IVUS substudy

BACKGROUND

Increasing coronary lesion calcification is thought to be associated with adverse percutaneous coronary intervention (PCI) and clinical outcomes. We investigated the effects of calcium burden on culprit lesion morphology and clinical events after intravascular ultrasound (IVUS)-guided PCI in the ADAPT-DES study.

METHODS

ADAPT-DES was a prospective, multicenter registry of 8582 consecutive patients undergoing successful PCI using DES. A pre-specified virtual histology (VH)-IVUS substudy of 638 culprit lesions (638 patients) had both pre- and post-PCI VH-IVUS. We divided lesions into tertiles according to pre-PCI percent dense calcium volume (DCV%=dense calcium/plaque volume×100).

RESULTS

Compared with low and intermediate DCV% tertiles, patients in the high DCV% tertile had the largest arc of superficial calcium, highest percentage of necrotic core volume, and smallest remodeling index; they were also more likely to have advanced lesion morphology such as attenuated plaque and VH thin-cap fibroatheromas. In the high DCV% tertile IVUS guidance was associated with a minimum stent area that was smaller than tertiles with less calcium (p=0.01), but acceptable range, and similar stent expansion (73.8±16.8% vs. 74.0±19.2% vs. 72.4±17.3%, p=0.62) after more frequent use of rotational atherectomy and higher maximum inflation pressure. There was no significant association between pre-PCI DCV% and 2-year target lesion revascularization or major adverse cardiac events (cardiac death, myocardial infarction, or stent thrombosis).

CONCLUSIONS

Increasing coronary artery calcification burden was associated with more advanced, complex VH-IVUS lesion morphology, but not with adverse clinical outcomes, perhaps due to more aggressive PCI techniques that optimized stent expansion.

High Sensitivity Troponins Discriminate Different Morphologies of Coronary Artery Plaques Being Assessed by Coronary Computed Tomography Angiography

BACKGROUND

This study evaluates the association between high sensitivity troponin I (hsTnI) and T (hsTnT) and the morphology of coronary artery plaques detected by coronary computed tomography angiography (CCTA) in patients with suspected coronary artery disease (CAD).

METHODS

Patients undergoing CCTA were prospectively enrolled. CCTA was indicated by a low to intermediate pretest probability for CAD during routine clinical care. Within 24 hours of CCTA examination, peripheral blood samples were taken to measure hsTnI, hsTnT, and N-terminal probrain natriuretic peptide (NT-proBNP).

RESULTS

A total of 99 patients were enrolled with 43% without CAD, 9% with noncalcified plaques, 28% with calcified plaques, and 19% with mixed type plaque lesions. Both hsTnI and hsTnT levels were able to discriminate significantly between the groups, especially in the presence of mixed coronary plaques (AUC range: 0.741-0.752; p = 0.0001). In multivariate logistic regression models, hsTnT, but not hsTnI, was still significantly associated with mixed coronary plaque morphology (odds ratio = 8.968; 95% CI 1.999-40.241; p = 0.004).

CONCLUSIONS

Both hsTnI and hsTnT are able to discriminate between different coronary artery plaques morphologies, whereas hsTnT was significantly associated with mixed coronary plaques in patients with suspected CAD. This trial is registered with NCT03074253.

Relationship between Automated Coronary Calcium Volumes and a Set of Manual Coronary Lumen Volume, Vessel Volume and Atheroma Volume in Japanese Diabetic Cohort

INTRODUCTION

A high degree of correlation exists between Coronary Artery Diseases (CAD) and calcification of the vessel wall. For Percutaneous Coronary Interventional (PCI) planning, it is essential to have an exact understanding of the extent to which calcium volume is correlated to the lumen, vessel, and atheroma volume regions in the coronary artery, which is unclear in recent studies.

AIM

Four automated Coronary Calcium Volume (aCCV) measurement methods {threshold, Fuzzy c-Means (FCM), K-means, and Hidden Markov Random Field (HMRF)} and its correlation with three manual (experts) coronary parameters namely: Coronary Vessel Volume (mCVV), Coronary Lumen Volume (mCLV), and Coronary Atheroma Volume (mCAV), was determined in a Japanese diabetic cohort.

MATERIALS AND METHODS

Intravascular Ultrasound (IVUS) image dataset from 19 patients (around 40,090 frames) was collected using 40 MHz IVUS catheter (Atlantis^® SR Pro, Boston Scientific^®, pullback speed of 0.5 mm/sec). The methodology consisted of automatically computing the calcium volume in the entire IVUS coronary videos using FCM, K-means, and HMRF based pixel classification and comparing it against the previously published threshold-based method. The Coefficient of Correlation (CC) was then established between the four aCCV and three manually (experts) coronary parameters: mCVV, mCLV, and mCAV computed using iMAP software Boston Scientific^®. Statistical tests (Two-tailed paired Student t-test, Wilcoxon signed rank test, Mann-Whitney test, Chi-square test, and Kolmogorov-Smirnov KS-test) were performed to demonstrate consistency, reliability, and accuracy of the proposed work.

RESULTS

Correlation coefficient of: (a) automated threshold-based volume; (b) automated FCM based volume; (c) automated K-means based volume; and (d) automated HMRF based volume and corresponding three manually (expert's) coronary parameters (mCLV, mCVV, mCAV) were: (0.51, 0.40, 0.48), (0.52, 0.38, 0.49), (0.56, 0.45, 0.52), and (0.57, 0.42, 0.56), respectively. The CC between age and haemoglobin was 0.50.

CONCLUSION

Automated coronary volume measurement using HMRF method is more accurate compared to threshold, FCM, and K-means-based method, since it is more strongly correlated with three expert's readings.

Dense calcium and lesion-specific ischemia: A comparison of CCTA with fractional flow reserve

BACKGROUND AND AIMS

Studies evaluating the relationship between dense coronary calcium (DC) and myocardial ischemia have had incongruent results. We sought to clarify whether DC, as detected by computed coronary tomographic angiography (CCTA), is an independent predictor of ischemia as measured by invasive fractional flow reserve (FFR).

METHODS

In total, 249 (399 lesions) stable patients undergoing CCTA and invasive FFR were enrolled for this post-hoc analysis. DC was defined as plaque with ≥350 HU using quantification software, and ischemia was defined as FFR ≤0.80. We evaluated the relationship of dense calcium volume (DCV), lesion plaque volume (LPV), non-calcified plaque volume (NCV), and area stenosis (AS) with ischemia using logistic regression reporting odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

Mean age was 63.0 ± 8.6 years, and 73 (29.3%) were female. Mean DCV was higher in lesions with FFR ≤0.80 (57.0 ± 54.7 mm³vs. 37.6 ± 49.5 mm³, [p < 0.001]). DCV and LPV were closely correlated (Pearson's coefficient = 0.49 [p < 0.001]). After adjustment for AS, LPV (OR 1.01, 95% CI 1.00-1.04, p < 0.001) but not DCV (OR 1.01, 95% CI 0.96-1.06, p = 0.69) was independently associated with ischemia.

CONCLUSIONS

Dense calcium is not an independent predictor of ischemia, but rather a marker of aggregate LPV, which in turn, is predictive of ischemia.

The Role of a Coronary Artery Calcium Scan in Type 1 Diabetes

The coronary artery calcium (CAC) scan has recently emerged as a reproducible noninvasive test to detect asymptomatic atherosclerotic coronary artery disease. It has several advantages over the traditional cardiac stress testing modalities, including lower cost, greater sensitivity for nonobstructing coronary artery lesions, and excellent prognostic value when combined with the Framingham risk parameters. Its chief disadvantage is that it does not identify obstructing coronary artery lesions or noncalcified coronary artery plaque. A CAC scan utilizes a chest computed tomogram and computer software to calculate the amount of calcium in the four main coronary vessels. Calcium is deposited in coronary plaques so that the greater the calcium score, the greater the plaque burden. This, in turn, is the basis for predicting a 10-15-year risk of a cardiovascular event. Individuals with a zero calcium score have a very low 10-year risk of a cardiovascular event. Obtaining a calcium score in a diabetic patient permits rational decisions for prescribing statin therapy. In patients with a zero score, the initiation of statin therapy is not recommended because the 5-year incidence of atherosclerotic cardiovascular disease is so low. In patients with diabetes, it is recommended to repeat the calcium scan in 4-5 years to permit timely therapy in the event that the score becomes positive. Since statins mildly increase coronary calcium as part of the stabilization of plaque, a reduction in the calcium score should not be anticipated. However, progression of the calcium score by more than 15%/year (calculated from a repeat CAC scan) provides additional prognostic information of an indication of progression of atherosclerosis. In summary, the coronary calcium score is a major clinical advance for noninvasively detecting coronary artery disease and managing antiatherosclerotic therapy in type 1 diabetes.

Tracking Progression of Heart Disease with Cardiac Computed Tomography

The ability to follow changes in atherosclerotic plaque burden over time should provide an accurate measure of efficacy for different cardiovascular therapies. Coronary calcifications are associated with atherosclerotic coronary artery plaque, and the amount of coronary calcifications has been shown to correlate with the overall coronary plaque burden. The presence and extent of coronary calcifications can be assessed noninvasively by monitoring the progression of coronary calcification with electron beam tomography. With annual progression rates of 22% to 52% and a median interscan variability of only 5% to 8%, this technology provides an opportunity to monitor patients to assess the clinical efficacy of medical therapies in studies as short as 1 year. Several studies have demonstrated that the successful pharmacologic reduction of low-density lipoprotein cholesterol significantly mitigated the progression of the calcium score. Studies using serial computed tomographic scans indicate that the annual progression of coronary calcium varies between 30% and 50% in symptomatic or high-risk individuals and from 0% to 20% in patients treated effectively with lipid-lowering medication. An increased rate of progression of coronary calcium seems to indicate a substantially increased risk for adverse cardiac events, suggesting that this modality can be used to monitor the efficacy of therapy.

Progression of CAC Score and Risk of Incident CVD

OBJECTIVES

The authors sought to determine the relative contributions of baseline coronary artery calcification (CAC), follow-up CAC, and CAC progression on incident cardiovascular disease (CVD).

BACKGROUND

Repeat CAC scanning has been proposed as a method to track progression of total atherosclerotic burden. However, whether CAC progression is a useful predictor of future CVD events remains unclear.

METHODS

This was a prospective observational study of 5,933 participants free of CVD who underwent 2 examinations, including CAC scores, and subsequent CVD event assessment. CAC progression was calculated using the square root method. The primary outcome was total CVD events (CVD death, nonfatal myocardial infarction, nonfatal atherosclerotic stroke, coronary artery bypass surgery, percutaneous coronary intervention). Secondary outcomes included hard CVD events, total coronary heart disease (CHD) events, and hard CHD events.

RESULTS

CAC was detected at baseline in 2,870 individuals (48%). The average time between scans was 3.5 ± 2.0 years. After their second scan, 161 individuals experienced a total CVD event during a mean follow-up of 7.3 years. CAC progression was significantly associated with total CVD events (hazard ratio: 1.14, 95% confidence interval: 1.01 to 1.30 per interquartile range; p = 0.042) in the model including baseline CAC, but the contribution of CAC progression was small relative to baseline CAC (chi-square 4.16 vs. 65.92). Furthermore, CAC progression was not associated with total CVD events in the model including follow-up CAC instead of baseline CAC (hazard ratio: 1.05, 95% confidence interval: 0.92 to 1.21; p = 0.475). A model that included follow-up CAC alone performed as well as the model that included baseline CAC and CAC progression.

CONCLUSIONS

Although CAC progression was independently, but modestly, associated with CVD outcomes, this relationship was no longer significant when including follow-up CAC in the model. These findings imply that if serial CAC scanning is performed, the latest scan should be used for risk assessment, and in this context, CAC progression provides no additional prognostic information.

Progression of coronary artery calcification at the crossroads: sign of progression or stabilization of coronary atherosclerosis?

Coronary artery calcification (CAC) has been strongly established as an independent predictor of adverse events, with a significant incremental prognostic value over traditional risk stratification algorithms. CAC progression has been associated with a higher rate of events. In parallel, several randomized studies and meta-analysis have shown the effectiveness of statins to slow progression and even promote plaque regression. However, evidence regarding the effect of routine medical therapy on CAC has yielded conflicting results, with initial studies showing significant CAC regression, and contemporaneous data showing rather the opposite. Accordingly, there is currently a great controversy on whether progression of CAC is a sign of progression or stabilization of coronary artery disease (CAD). The finding of inexorable CAC progression despite the implementation of intensive contemporaneous medical therapy suggests that further understanding of this phenomenon should be undertaken before the implementation of CAC as a surrogate endpoint for longitudinal studies, or for prospective follow-up of patients under routine medical treatment.

Defining the non-vulnerable and vulnerable patients with computed tomography coronary angiography: evaluation of atherosclerotic plaque burden and composition

The shift from coronary plaque stability to plaque instability remains poorly understood despite enormous efforts and expenditures have been assigned to the study of the subject. On the other hand, there have been serious advances in imaging helping us to characterizenon-vulnerable patients The latter has much more value in the clinical decision-making process since it provides high certainty that the patient's probability of a future acute event is low and treatment decisions should be made accordingly. Although coronary plaque rupture is still recognized as the main source of acute thrombotic events, numerous studies have shown that the prediction of events on an individual basis is far more complex and demands a more open approach aimed at characterizing patient risk rather than assessing the risk of thrombosis of a single plaque. Computed tomography coronary angiography (CTCA) has the ability to evaluate non-invasively the extent, burden, severity, and characteristics of coronary artery disease (CAD) and has a close relationship to intravascular ultrasound. On the basis of an excellent negative predictive value with an annualized event rate of ∼0.20% assessed over more than 6000 patients, thus providing a 5-year warranty period, CTCA has been identified as the finest non-invasive tool to exclude CAD. This means that CTCA is able to reliably characterize the non-vulnerable patient. Conversely, in the past few years, several studies have attempted to establish CTCA-derived predictors of acute coronary syndromes, both from a lesion level and a patient level basis with very low positive predictive value, thus questioning the vulnerable patient/plaque concept.

Intravascular imaging of coronary calcification and its clinical implications

Calcium impacts the natural history and treatment of coronary artery disease in many ways. Intravascular imaging studies, mostly intravascular ultrasound, but more recently studies using optical coherence tomography, have been instrumental in increasing our understanding of the relationship between calcium and coronary atherosclerosis, the predictors, the natural history of this relationship, and the impact on treatment. On one hand, stable coronary lesions are associated with more calcium than unstable lesions; and the amount of calcium may affect the success of percutaneous coronary intervention. On the other hand, calcium correlates with plaque burden; unstable lesions are associated with focal calcium deposits; and calcific nodules are one of the morphologies of vulnerable plaque. This review focuses on more than 20 years of intravascular imaging studies of the relationship between calcium and coronary atherosclerosis.

Enhanced characterization of calcified areas in intravascular ultrasound virtual histology images by quantification of the acoustic shadow: validation against computed tomography coronary angiography

We enhance intravascular ultrasound virtual histology (VH) tissue characterization by fully automatic quantification of the acoustic shadow behind calcified plaque. VH is unable to characterize atherosclerosis located behind calcifications. In this study, the quantified acoustic shadows are considered calcified to approximate the real dense calcium (DC) plaque volume. In total, 57 patients with 108 coronary lesions were included. A novel post-processing step is applied on the VH images to quantify the acoustic shadow and enhance the VH results. The VH and enhanced VH results are compared to quantitative computed tomography angiography (QTA) plaque characterization as reference standard. The correlation of the plaque types between enhanced VH and QTA differs significantly from the correlation with unenhanced VH. For DC, the correlation improved from 0.733 to 0.818. Instead of an underestimation of DC in VH with a bias of 8.5 mm(3), there was a smaller overestimation of 1.1 mm(3) in the enhanced VH. Although tissue characterization within the acoustic shadow in VH is difficult, the novel algorithm improved the DC tissue characterization. This algorithm contributes to accurate assessment of calcium on VH and could be applied in clinical studies.

Association between serum gamma-glutamyltransferase and the progression of coronary artery calcification

BACKGROUND

Elevated serum gamma-glutamyltransferase (GGT) has been demonstrated to be associated with coronary artery calcification (CAC). CAC progression is an important marker of atherosclerosis and correlates with future cardiovascular risk. However, there is a lack of research that directly examines the association between serum GGT and CAC progression. The aim of this study was to elucidate the association between serum GGT activity and CAC progression.

METHODS

We enrolled 1246 asymptomatic participants who underwent repeated CAC score measurement during routine health examinations. To eliminate the dependence of the inter scan variability on the baseline CAC scores, square root-transformed CAC scores were used to analyze CAC progression. In addition, the annualized rate of change in CAC scores was computed.

RESULTS

Serum GGT activities were significantly higher in "progressors" than "nonprogressors". The prevalence of progression increased with the GGT tertile (11.9%, 20.1% and 27.9% in the 1st, 2nd, and 3rd GGT tertiles, respectively; p < 0.001). In the multivariate logistic regression analysis, the odds ratio (95% confidence interval) for CAC score progression was 1.85 (1.14-3.00) in the highest GGT tertile group. By multivariate linear regression analysis, baseline serum GGT activity demonstrated a positive association with the annualized change in CAC score (β = 0.002; p = 0.006) after adjusting for cardiovascular risk factors.

CONCLUSION

Elevated serum GGT levels are independently associated with CAC progression. Serum GGT levels may be a potential biomarker of future coronary atherosclerosis and prognosis.

Current and future trends in multimodality imaging of coronary artery disease

Nowadays, there is a wide array of imaging studies available for the evaluation of coronary artery disease, each with its particular indications and strengths. Cardiac single photon emission tomography is mostly used to evaluate myocardial perfusion, having experienced recent marked improvements in image acquisition. Cardiac PET has its main utility in perfusion imaging, atherosclerosis and endothelial function evaluation, and viability assessment. Cardiovascular computed tomography has long been used as a reference test for non-invasive evaluation of coronary lesions and anatomic characterization. Cardiovascular magnetic resonance is currently the reference standard for non-invasive ventricular function evaluation and myocardial scarring delineation. These specific strengths have been enhanced with the advent of hybrid equipment, offering a true integration of different imaging modalities into a single, simultaneous and comprehensive study.

Coronary Artery Calcium Assessment in CKD: Utility in Cardiovascular Disease Risk Assessment and Treatment?

Coronary artery calcification (CAC) is a strong predictor of cardiovascular event rates in the general population, and scoring with multislice computed tomography commonly is used to improve risk stratification beyond clinical variables. CAC is accelerated in chronic kidney disease, but this occurs as a result of 2 distinct pathologic processes that result in medial (arteriosclerosis) and intimal (atherosclerosis) deposition. Although there are data that indicate that very high CAC scores may be associated with increased risk of death in hemodialysis, average CAC scores in most patients are elevated at a level at which discriminatory power may be reduced. There is a lack of data to guide management strategies in these patients based on CAC scores. There are even fewer data available for nondialysis patients, and it is uncertain whether CAC score confers an elevated risk of premature cardiovascular morbidity and mortality in such patients. In this article, we review the evidence regarding the utility of CAC score for noninvasive cardiovascular risk assessment in individuals with chronic kidney disease, using a clinical vignette that highlights some of the limitations in using CAC score and considerations in risk stratification.